Agenda packet — Lake Forest City Council, March 17, 2026 (part 6 of 9)

10.9 8.6

8.9 7.6
BC=12
19 48
BC=38
50/5"
BC=50/6"
BC=50/6"
BC=50/2"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-11

LABORATORY RESULTS
Lithologic Description
BORING LOG B-10
PAGE:

BORING LOG B-10
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67706°
Longitude: -117.66989°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1549
123.6
108.7
17 Asphalt: approximately 4"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
non-plastic to low plasticity, brown, moist,
trace subrounded gravel
Silty SAND (SM): fine to medium sand, olive
gray, moist, trace clay
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
gray, decrease in fines
excavates as poorly graded sand (SP)
olive gray
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
11"
5"
3"
5"

12.1 12.4

9.2 9.3
BC=20
15 22
BC=28
50/5"
BC=50/5"
BC=50/3"
BC=50/5"
Hand auger 5ft bgs
Corrosion Test
Modified Proctor
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-12

LABORATORY RESULTS
Lithologic Description
BORING LOG B-11
PAGE:

BORING LOG B-11
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67763°
Longitude: -117.66833°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1550
124.0
108.7
Asphalt: approximately 2.5"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist
gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as poorly graded sand with silt
(SP-SM)
excavates as silty sand (SM)
increase in sand, trace coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
11"
6"
6"
4"

13.0 9.9

9.8 8.7
BC=8
16 33
BC=33
50/5"
BC=50/6"
BC=50/6"
BC=50/4"
NP
Hand auger 5ft bgs
NP
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-13

LABORATORY RESULTS
Lithologic Description
BORING LOG B-12
PAGE:

BORING LOG B-12
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67733°
Longitude: -117.66861°
Ground Surface Elevation (ft.): 778.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1551
123.8
Asphalt: approximately 3.5"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace subangular gravel up to

0.5"
Silty SAND (SM): fine to medium sand, light
gray, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace clay
decrease in fines, trace coarse sand
increase in fines, fine to coarse sand
olive gray, increase in fines, fine sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
5"
7"
9"
12"

10.3 9.7

8.2 BC=8
18 40
BC=50/5"
BC=37
50/1"
BC=26
50/3"
BC=25
50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-14

LABORATORY RESULTS
Lithologic Description
BORING LOG B-13
PAGE:

BORING LOG B-13
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67742°
Longitude: -117.66823°
Ground Surface Elevation (ft.): 780.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1552
121.4
116.8
15 Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
olive gray, medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
decrease in fines
excavates as silty clayey sand (SC-SM),
non-plastic to low plasticity
excavates as silty sand (SM)
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
12"
3"
3"
6"

13.9 13.5

7.8 4.3
BC=4
5 9
BC=13
50/6"
BC=50/3"
BC=50/3"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-15

LABORATORY RESULTS
Lithologic Description
BORING LOG B-14
PAGE:

BORING LOG B-14
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67711°
Longitude: -117.66847°
Ground Surface Elevation (ft.): 777.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1553
121.3
116.3
Asphalt: approximately 2.5"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist
olive gray, medium dense, increase in fines
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as pooly graded sand with silt
(SP-SM), light gray
excavates as pooly graded sand (SP)
excavates as silty sand (SM)
excavates as pooly graded sand with silt
(SP-SM), light gray
18"
6"
6"
10"
4"
3"
6"

12.4 7.9

9.8 10.8
BC=25
18 19
BC=50/6"
BC=50/6"
BC=30
50/4"
BC=50/4"
BC=50/3"
BC=50/6"
NP
Hand auger 5ft bgs
NP
1 of 2

FIELD EXPLORATION
A-16

LABORATORY RESULTS
Lithologic Description
BORING LOG B-15
PAGE:

BORING LOG B-15
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67720°
Longitude: -117.66806°
Ground Surface Elevation (ft.): 779.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1554
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as silty sand (SM), fine sand
excavates as pooly graded sand (SP), light
gray
The boring was terminated at approximately
49 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
6"
4"
6"
4"
BC=50/6"
BC=50/4"
BC=50/6"
BC=50/4"
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
2 of 2

FIELD EXPLORATION
A-17

LABORATORY RESULTS
Lithologic Description
BORING LOG B-15
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
40 45
50 55
60 65
Elevation (feet)
740
735
730
725
720
715
710
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
8 9
10 11
PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1555
125.1
115.7
14 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Silty SAND (SM): fine to medium sand, olive
gray, moist, trace clay
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist. highly
weathered, very weak (R1)
decrease in fines
excavates as poorly graded sand with silt
(SP-SM)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
12"
6"

10.1 11.0

9.0 8.9
BC=10
20 36
BC=32
50/6"
BC=50/6"
Hand auger 5ft bgs
Corrosion Test
Modified Proctor
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-18

LABORATORY RESULTS
Lithologic Description
BORING LOG B-16
PAGE:

BORING LOG B-16
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67661°
Longitude: -117.66814°
Ground Surface Elevation (ft.): 776.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1556
122.6
109.0
22 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, brown, moist, angular to
subangular gravel up to 0.5"
Capistrano Formation
SANDSTONE: excavates as sity sand (SM),
light gray, fine to medium sand, highly
weathered, very weak (R1)
trace clay
excavates as clayey sand (SC), low plasticity
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
17"
16"
6"

13.6 10.3

19.7 BC=10
36 50/5"
BC=25
36 50/4"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-19

LABORATORY RESULTS
Lithologic Description
BORING LOG B-17
PAGE:

BORING LOG B-17
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67632°
Longitude: -117.66782°
Ground Surface Elevation (ft.): 775.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1557
114.7
Asphalt: approximately 3.5"
Aggregate Base: approximately 4"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist
Silty SAND (SM): fine to coarse sand, gray,
moist
fine to medium sand
Capistrano Formation
SANDSTONE: excavates as poorly graded
sand (SP-SM), light gray, fine to medium
sand, highly weathered, very weak (R1)
excavates as sity sand (SM)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
6"
6"

11.7 9.3

9.1 BC=16
24 44
BC=50/6"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-20

LABORATORY RESULTS
Lithologic Description
BORING LOG B-18
PAGE:

BORING LOG B-18
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67659°
Longitude: -117.66719°
Ground Surface Elevation (ft.): 776.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1558
121.9
Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Silty Clayey SAND (SC-SM): fine to medium
sand, brown, moist, trace angular fine gravel
Silty SAND (SM): fine sand, light gray, moist
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
6"
12"

12.9 10.8

10.6 BC=7
14 23
BC=50/6"
BC=31
50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-21

LABORATORY RESULTS
Lithologic Description
BORING LOG B-19
PAGE:

BORING LOG B-19
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67708°
Longitude: -117.66777°
Ground Surface Elevation (ft.): 780.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1559
122.0
22 Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, olive gray, moist
Silty SAND (SM): fine to medium sand, olive
gray, moist
Capistrano Formation
SANDSTONE (SM): light gray, moist,
excavates as silty sand (SM), light gray, fine to
coarse sand, highly weathered, very weak
(R1)
excavates as poorly graded sand (SP)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
6"
5"

9.6 16.3

10.6 8.7
BC=4
5 15
BC=50/6"
BC=50/5"
30 Hand auger 5ft bgs
8 R-Value Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-22

LABORATORY RESULTS
Lithologic Description
BORING LOG B-20
PAGE:

BORING LOG B-20
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67742°
Longitude: -117.66756°
Ground Surface Elevation (ft.): 782.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1560
18 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as clayey sand
(SC), light gray, fine to medium sand, moist,
highly weathered, very weak (R1)
excavates as silty sand (SM), olive
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
1"
NR
11"

9.8 8.9
BC=50/1"
BC=50/1"
BC=24
50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-23

LABORATORY RESULTS
Lithologic Description
BORING LOG B-21
PAGE:

BORING LOG B-21
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67781°
Longitude: -117.66755°
Ground Surface Elevation (ft.): 784.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1561
121.4
117.9
17 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, trace
clay, highly weathered, very weak (R1)
increase in fines, fine sand
excavates as clayey sand (SC), light gray, fine
sand, low plasticity
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
12"
9"
3"

13.0 9.8

10.2 BC=17
50/6"
BC=24
50/3"
BC=50/3"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-24

LABORATORY RESULTS
Lithologic Description
BORING LOG B-22
PAGE:

BORING LOG B-22
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67793°
Longitude: -117.66812°
Ground Surface Elevation (ft.): 783.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1562
123.3
Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace fine subrounded gravel
Capistrano Formation
SANDSTONE: excavates as silty sad (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace clay
olive gray
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
12"
16"
2"

11.7 12.6

10.6 7.3
BC=16
50/6"
BC=40
37 50/4"
BC=50/6"
31 Hand auger 5ft bgs
11 R-Value Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-25

LABORATORY RESULTS
Lithologic Description
BORING LOG B-23
PAGE:

BORING LOG B-23
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67842°
Longitude: -117.66787°
Ground Surface Elevation (ft.): 787.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
785
780
775
770
765
760
755
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1563
116.8
17 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
dark brown, moist, trace fine gravel
Capistrano Formation
SANDSTONE: excavates silty sand (SM),
light gray, fine to medum sand, moist, highly
weathered, very weak (R1)
decrease in fines
increase in fines, fine sand
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
6"
14"

10.9 10.4

9.4 BC=13
30 40
BC=50/6"
BC=30
38 50/2"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-26

LABORATORY RESULTS
Lithologic Description
BORING LOG B-24
PAGE:

BORING LOG B-24
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67844°
Longitude: -117.66842°
Ground Surface Elevation (ft.): 785.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1564
122.8
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace fine gravel
Capistrano Formation
SANDSTONE: excavates silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace coarse sand
decrease in fines
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
6"
8"
1"

12.7 10.7

4.3 BC=50/6"
BC=25
50/2"
BC=50/1"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-27

LABORATORY RESULTS
Lithologic Description
BORING LOG B-25
PAGE:

BORING LOG B-25
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67723°
Longitude: -117.66720°
Ground Surface Elevation (ft.): 781.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1565
118.9
25 Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, light gray, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, higly
weatheres, very weak (R1)
decrease in fines
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
4"
8"
6"

10.6 10.5

8.8 BC=50/4"
BC=27
50/2"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-28

LABORATORY RESULTS
Lithologic Description
BORING LOG B-26
PAGE:

BORING LOG B-26
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67695°
Longitude: -117.66739°
Ground Surface Elevation (ft.): 779.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1566
124.4
117.8
114.9
Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND with Gravel (SM): fine to medium
sand, brown, moist
Capistrano Formation
SANDSTONE: excavaes as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
increase in fines
fine sand
decrease in fines
increase in fines
excavates as poorly graded sand with silt
(SP-SM)
excavates as poorly graded sand (SP), fine
sand
excavates as silty sand (SM)
The boring was terminated at approximately
26 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
9"
12"
6"
12"
6"
6"
5"
11"

10.0 9.6

9.7 12.8

11.2 BC=25
50/3"
BC=23
50/6"
BC=50/6"
BC=14
50/6"
BC=50/6"
BC=50/6"
BC=50/5"
BC=31
50/5"
NP
Hand auger 5ft bgs
NP Corrosion Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-29

LABORATORY RESULTS
Lithologic Description
BORING LOG B-27
PAGE:

BORING LOG B-27
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67696°
Longitude: -117.66696°
Ground Surface Elevation (ft.): 779.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 8
9 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1567
114.1
113.5
112.6
22 Asphalt: approximately 3.5"
Aggregate Base: approximately 4"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, brown, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
yellow, fine to medium sand, moist, highly
weathered, very weak (R1)
decrease in fines
excavates as clayey sand (SC), gray, fine
sand, low to medium plasticity
excavates as silty sand (SM), light gray, fine to
medium sand, trace clay
fine to coarse sand, decrease in fines
fine to medium sand
decrease in fines
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand
excavates as poorly graded sand (SP), fine to
coarse sand
The boring was terminated at approximately
25 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
10"
5"
9"
6"
12"
6"
11"
2"

8.8 11.0

9.6 7.6

8.2 BC=34
50/4"
BC=50/5"
BC=34
50/3"
BC=50/6"
BC=27
50/6"
BC=50/6"
BC=25
50/5"
BC=50/2"
Hand auger 5ft bgs
Direct Shear Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-30

LABORATORY RESULTS
Lithologic Description
BORING LOG B-28
PAGE:

BORING LOG B-28
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67686°
Longitude: -117.66706°
Ground Surface Elevation (ft.): 778.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 8
PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1568
97 19
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Silty Clayey SAND (SC-SM): fine to medium
sand, brown, moist
The boring was terminated at approximately 5
ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.

Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-31

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-1
PAGE:

BORING LOG INF-1
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67731°
Longitude: -117.67016°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1569
100 20
Asphalt: approximately 5"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace angular gavel
light gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
gray, fine to medium sand, moist, trace clay,
highly weathered, very weak (R1)
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
11"
BC=8
14 12
BC=39
50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-32

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-2
PAGE:

BORING LOG INF-2
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67685°
Longitude: -117.66987°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1570
99 15
Asphalt: approximately 5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist
olive
The boring was terminated at approximately 5
ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.

Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-33

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-3
PAGE:

BORING LOG INF-3
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67648°
Longitude: -117.66952°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1571
100 7.5
Asphalt: approximatey 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace angular gravel
ollive gray
Capistrano Formation
SANDSTONE: excavates as well graded
sand with silt (SW-SM), olive gray, fine to
medium sand, moist highly weathered, very
weak (R1)
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
18"
BC=7
10 12
BC=18
34 50
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-34

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-4
PAGE:

BORING LOG INF-4
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67622°
Longitude: -117.66915°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1572
25003229.001A/LH25R178197 April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com

APPENDIX B

LABORATORY TESTING
Item: 11
1573
25003229.001A/LH25R178197 Page B-1 April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com

APPENDIX B

LABORATORY TESTING

GENERAL
Laboratory tests were performed on selected samples as an aid in classifying the soils and to evaluate physical properties of the soils that may affect foundation design and construction procedures. Laboratory testing was performed by both Kleinfelder and AP Engineering and Testing, Inc. of Pomona, California. The tests were performed in general conformance with the current ASTM or Caltrans standards. A description of the laboratory-testing program is presented below.

MOISTURE AND UNIT WEIGHT
Moisture content and dry unit weight testing was performed on a selected sample recovered from our borings. Moisture contents were determined in general accordance with ASTM Test Method D2216; dry unit weight was calculated using the entire weight of the samples collected in general accordance with ASTM Test Method D7263. Results of these tests are presented on the boring logs in Appendix A.

WASH SIEVE
Selected soil samples were tested for the percent passing the No. 200 sieve, which was performed by wash sieving in accordance with ASTM Standard Test Method D1140. Results of these tests are presented on the boring logs in Appendix A.

SIEVE AND HYDROMETER ANALYSIS
Sieve analysis of selected samples was performed to evaluate the grain size distribution of the onsite soils and to aid in classification of the soils. Sieve analysis and hydrometer analysis was performed in accordance with ASTM Standard Test Method D6913. The results of the tests are presented on the boring logs in Appendix A and as an attachment in this appendix.

DIRECT SHEAR
Direct shear testing was performed on a relatively undisturbed sample to evaluate the shear strength characteristics of the onsite soils. Direct shear testing was performed in general accordance with ASTM Standard Test Method D3080. The results of the testing are presented as an attachment in this appendix.

Item: 11
1574
25003229.001A/LH25R178197 Page B-2 April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com

MODIFIED PROCTOR
Modified Proctor (maximum dry density and optimum moisture content) testing was performed on two select bulk samples of the near surface soils to evaluate the compaction characteristics of the onsite soils. The testing was performed in general accordance with ASTM Standard Test Method D1557. The test results are attached to this appendix.

R-VALUE
Resistance value (R-value) tests were performed on two select bulk soil samples to evaluate pavement support characteristics of the near-surface onsite soils. R-value tests were performed in accordance with ASTM Standard Test Method D2844. The test results are attached to this appendix.

SOIL CORROSIVITY TESTS
A series of chemical tests were performed on selected samples of the near-surface soils to estimate pH, resistivity and sulfate and chloride contents. The samples were tested for pH and minimum resistivity, soluble chlorides, and soluble sulfates, respectively. The tests were performed by AP Engineering and Testing, Inc. Test results may be used by a qualified corrosion engineer to evaluate the general corrosion potential with respect to construction materials. The results of the tests are presented in the body of the report and are attached to this appendix.

Item: 11
1575
SYMBOL
1 GRAVEL

3.5 0.0

1.2 SAMPLE
NO.

SAMPLE IDENTIFICATION
BORING
NO.

INF-1
INF-2
INF-3

4.5-5

8.5 4.5-5

PERCENTAGES
1 2
NM
DEPTH
(ft.) FINES

18.6 20.3

15.3 SAND

77.9 79.7

83.5 NM

SOIL CLASSIFICATION
Silty Sand (SM)
Silty Sand (SM)
Silty Sand (SM)
PI

ATTERBERG LIMITS
LL
NM NM
NM
NM
PL
NM
NM NM
INF-4 2 8.5 0.0 92.5 7.5 NM NM NM Well Graded Sand with Silt (SW) 0 10
20 30
40 50
60 70
80 90
100
100.000 10.000 1.000 0.100 0.010 0.001

CUMULATIVE PERCENT PASSING

GRAIN SIZE IN MILLIMETERS

SILT CLAY

COBBLE GRAVEL SAND SILT CLAY

GRAIN SIZE DISTRIBUTION
Proposed Costco Wholesale Warehouse and
Fuel Facility
26602 Towne Centre Drive
2/10/2025 Foothill Ranch, California
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Well Graded Sand with Silt (SW-SM) Silty Clayey Sand (SC-SM) Clayey Sand (SC) Silty Sand (SM) Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1576
Testing performed in general accordance with ASTM D4318 1 1
5 5

7.5 Silty Sand (SM)
Silty Sand (SM)
SYMBOL
25 22 3

N/A N/A N/A
27 22 5
5 B-5 1
B-1 1
B-3 2
B-7
B-9

SOIL CLASSIFICATION

SAMPLE IDENTIFICATION
Silty Sand (SM)
Silty Sand (SM)
30 25 5
29 26 3

ATTERBERG LIMITS

LL PL PI BORING
NO.

SAMPLE
NO. DEPTH (ft)
5 Silty Sand (SM)
MH or OH
ML or OL
CH or OH
CL-ML
CL or OL
0 10
20 30
40 50
60 0 10 20 30 40 50 60 70 80 90 100 110

PLASTICITY INDEX (PI)

LIQUID LIMIT (LL)
PROJECT NO.:

TESTED BY:

DATE:

CHECKED BY:

DATE:

FIGURE
0 PROJECT NO.: 25003229.001A
TESTED BY: N.Brown
DATE: 2/5/2025
CHECKED BY: M.Magaña
DATE: 2/10/2025
Proposed Costco Wholesale Warehouse
and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
PLASTICITY TESTING KLEINFELDER - 620 South Magnolia Ave, Bldg G | Ontario, CA | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive

NP NP NP
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1577
Testing performed in general accordance with ASTM D4318

SOIL CLASSIFICATION

SAMPLE IDENTIFICATION
Silty Sand (SM)
Silty Sand (SM)

N/A N/A N/A

ATTERBERG LIMITS

LL PL PI BORING
NO.

SAMPLE
NO. DEPTH (ft)
0-5 Silty Sand with Gravel (SM)
SYMBOL
30 22 8
31 20 11

N/A N/A N/A
0-5
B-20 1
B-12 1
B-15 1
B-23
B-27
0-5
5 5
Clayey Sand (SC)
Clayey Sand (SC)
1 1
MH or OH
ML or OL
CH or OH
CL-ML
CL or OL
0 10
20 30
40 50
60 0 10 20 30 40 50 60 70 80 90 100 110

PLASTICITY INDEX (PI)

LIQUID LIMIT (LL)
FIGURE
0 PROJECT NO.: 25003229.001A
TESTED BY: N.Brown
DATE: 2/10/2025
CHECKED BY: M.Magaña
DATE: 2/11/2025
Proposed Costco Wholesale Warehouse
and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California

PLASTICITY TESTING
KLEINFELDER - 620 South Magnolia Ave, Bldg G | Ontario, CA | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive

NPNPNP NPNPNP NPNPNP
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1578
Project Name: Costco Foothill Ranch, CA GEO Tested By: ST Date: 01/27/25 Project No.: 25003229.001A Computed By: JP Date: 02/03/25 Boring No.: B‐28 Checked by: AP Date: 02/03/25
Sample No.: 4 Depth (ft): 12.5
Sample Type: Mod. Cal.

Soil Description: Silty Sand
Test Condition: Inundated Shear Type: Regular
Wet
Unit Weight
(pcf)
Dry
Unit Weight
(pcf)
Initial
Moisture
Content (%)
Final
Moisture
Content (%)
Initial Degree
Saturation
(%)
Final Degree
Saturation
(%)
Normal
Stress
(ksf)
Peak
Shear
Stress (ksf)
Ultimate
Shear
Stress (ksf)
1 1.058 0.718
2 2.196 1.476
4 3.744 2.580
90 DIRECT SHEAR TEST RESULTS
ASTM D 3080
122.2 113.5 7.6 16.1 43
0 1
2 3
4 5
0 0.1 0.2 0.3
Shear Stress (ksf)
Shear Deformation (Inches)
1 ksf 2 ksf 4 ksf
0 1
2 3
4 5
6 0 1 2 3 4 5 6 7 8 9 10 11 12
Shear Stress (ksf)
Normal Stress (ksf)
Peak: C=200 psf; ɸ=42˚
Ultimate: C=100 psf; ɸ=32˚
Normal Stress:

Item: 11
1579
Boring No.: B-11
Sample No.: 1
Depth: 0-5
Material Description: Clayey Sand (SC)
Maximum Dry Unit Weight (pcf)
Optimum Water Content (%)
Oversize Fraction, retained on 3/8 (%)
Tested in accordance with: ASTM D1557, Method B
na
<5
Bulk Specific Gravity of Oversize Fraction na

7.6 Uncorrected Corrected
129.5 na
na = not applicable
Compaction Curve
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive 2/10/2025
25003229.001A
D.Montemayor II
2/4/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:
100
110
120
130
140

0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Unit Weight (pcf)
Water Content (%)

2.75 2.70

2.65 2.60
Compaction Curve
Compaction Curve, Corrected
KLEINFELDER - 620 South Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1580
Boring No.: B-16
Sample No.: 1
Depth: 0-5
Material Description: Clayey Sand (SC)
Maximum Dry Unit Weight (pcf)
Optimum Water Content (%)
Oversize Fraction, retained on 3/8 (%)
Tested in accordance with: ASTM D1557, Method B
na
<5
Bulk Specific Gravity of Oversize Fraction na

8.9 Uncorrected Corrected
128 na
na = not applicable
Compaction Curve
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive 2/10/2025
25003229.001A
D.Montemayor II
2/4/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:
100
110
120
130
140

0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Unit Weight (pcf)
Water Content (%)

2.75 2.70

Sample No.:

Depth:

Material Description:

Test Procedure: ASTM D2844
Specimen No. B
Moisture at Test (%)
Dry Unit Weight at Test (pcf)
Expansion Pressure (psf)
19 15

21.6 568.4
A

10.2 123.6

0.0 792.0
B-20
Exudation Pressure (psi)
Resistance Value
R - VALUE AT 300 PSI EXUDATION PRESSURE
1 10.6
Clayey Sand (SC)
C
119.3

11.5 123.0
0-5

26.0 212.4
1430
0 10
20 30
40 50
60 70
80 90
100
050100150200250300350400450500550600650700750800
R-Value
Exudation Pressure (psi)

R-VALUE
Proposed Costco Wholesale Warehouse and Fuel
Facility
26602 Towne Centre Drive
Foothill Ranch, California 2/11/2025
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1582
Boring No.:

Sample No.:

Depth:

Material Description:

Test Procedure: ASTM D2844
Specimen No. B
Moisture at Test (%)
Dry Unit Weight at Test (pcf)
Expansion Pressure (psf)
18 16

21.6 543.2
A

11.6 118.3

0.0 260.0
B-23
Exudation Pressure (psi)
Resistance Value
R - VALUE AT 300 PSI EXUDATION PRESSURE
1 11.1
Clayey Sand (SC)
C
119.1

10.6 119.6
0-5

26.0 641.2
2016
0 10
20 30
40 50
60 70
80 90
100
050100150200250300350400450500550600650700750800
R-Value
Exudation Pressure (psi)

R-VALUE
Proposed Costco Wholesale Warehouse and Fuel
Facility
26602 Towne Centre Drive
Foothill Ranch, California 2/11/2025
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1583

CORROSION TEST RESULTS
Client Name: Kleinfelder AP Job No.: 25-1060
Project Name: Costco Foothill Ranch, CA GEO Date: 01/28/25 Project No.: 25003229.001A
Boring Sample Depth Soil pH Sulfate Content Chloride Content No. No. (feet) Description (ppm) (ppm)
B-2 1 0-5 Sandy Clay 8.0 37 6
B-11 1 0-5 Sandy Clay 8.0 8 4
B-16 1 0-5 Clayey Sand 8.4 119 12
B-27 1 0-5 Clayey Sand 8.7 101 9

NOTES: Resistivity Test and pH: California Test Method 643 Sulfate Content : California Test Method 417
Chloride Content : California Test Method 422
ND = Not Detectable
NA = Not Sufficient Sample
NR = Not Requested
Minimum
(ohm-cm)
2,767
Resistivity
3,147
1,907
2,048
Item: 11
1584
25003229.001A/LH25R178197 April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com

APPENDIX C

INFILTRATION TEST RESULTS
Item: 11
1585
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-1
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 3.05 3.25 0.20 12.5 0.4
30 60 3.05 3.20 0.15 16.7 0.3
30 90 3.10 3.25 0.15 16.7 0.3
30 120 3.10 3.25 0.15 16.7 0.3
30 150 3.05 3.15 0.10 25.0 0.2
30 180 3.10 3.25 0.15 16.7 0.3
30 210 3.10 3.25 0.15 16.7 0.3
30 240 3.10 3.20 0.10 25.0 0.2
30 270 3.05 3.20 0.15 16.7 0.3
30 300 3.10 3.25 0.15 16.7 0.3
30 330 3.05 3.20 0.15 16.7 0.3
30 360 3.10 3.25 0.15 16.7 0.3

2.0 5.0

1.8 2
8 Boring Percolation Test Method Figure
25003229.001A
Proposed Costco Wholesale Warehouse and Fuel Facility
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):
26602 Towne Centre Drive
Foothill Ranch, California
Project No.:

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1586
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-2
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 8.05 8.10 0.05 50.0 0.1
30 60 8.05 8.10 0.05 50.0 0.1
30 90 8.05 8.10 0.05 50.0 0.1
30 120 8.05 8.10 0.05 50.0 0.1
30 150 8.05 8.10 0.05 50.0 0.1
30 180 8.05 8.10 0.05 50.0 0.1
30 210 8.05 8.10 0.05 50.0 0.1
30 240 8.05 8.10 0.05 50.0 0.1
30 270 8.05 8.10 0.05 50.0 0.1
30 300 8.05 8.10 0.05 50.0 0.1
30 330 8.05 8.10 0.05 50.0 0.1
30 360 8.05 8.10 0.05 50.0 0.1

5.0 10.0

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1587
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-3
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 3.05 3.10 0.05 50.0 0.1
30 60 3.05 3.10 0.05 50.0 0.1
30 90 3.05 3.10 0.05 50.0 0.1
30 120 3.05 3.10 0.05 50.0 0.1
30 150 3.05 3.07 0.02 125.0 0.04
30 180 3.05 3.10 0.05 50.0 0.1
30 210 3.05 3.07 0.02 125.0 0.04
30 240 3.05 3.07 0.02 125.0 0.04
30 270 3.05 3.10 0.05 50.0 0.1
30 300 3.05 3.10 0.05 50.0 0.1
30 330 3.05 3.10 0.05 50.0 0.1
30 360 3.05 3.10 0.05 50.0 0.1

2.0 5.1

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1588
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-4
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 7.70 7.75 0.05 50.0 0.1
30 60 7.70 7.75 0.05 50.0 0.1
30 90 7.70 7.75 0.05 50.0 0.1
30 120 7.65 7.67 0.02 125.0 0.03
30 150 7.65 7.70 0.05 50.0 0.1
30 180 7.65 7.70 0.05 50.0 0.1
30 210 7.65 7.70 0.05 50.0 0.1
30 240 7.65 7.70 0.05 50.0 0.1
30 270 7.65 7.70 0.05 50.0 0.1
30 300 7.65 7.70 0.05 50.0 0.1
30 330 7.65 7.70 0.05 50.0 0.1
30 360 7.65 7.70 0.05 50.0 0.1

5.0 10.1

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1589
PC Attachment 5.4
Item: 11
1590
Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix G
Appendix G – WQMP

Item: 11
1591
Santa Ana Region
Priority Project
Preliminary Water Quality
Management Plan
(PWQMP)
Project Name:

Costco Foothill Ranch
26602 TOWNE CENTRE DRIVE, FOOTHILL RANCH, CA
612-093-13
Prepared for:

Costco Wholesale
9 Corporate Park, Suite 230
Irvine, CA 92606
(760) 707-9124
Prepared by:

Kimley-Horn and Associates, Inc
Ahmed Zuwawa, PE
1100 Town and Country Rd, Suite 700
Orange, CA 92868
(714) 705-1366
Submittal Date: May 18,2025
Revision Date: September 19,2025
Revision Date: November 3,2025
Approval Date:

Item: 11
1592
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Owner’s Certification
Costco Foothill Ranch WQMP November 2025 Page i
This Water Quality Management Plan (WQMP) has been prepared for Costco Wholesale by Kimley-Horn and Associates, Inc. The WQMP is intended to comply with the requirements of the County of Orange NPDES Stormwater Program requiring the preparation of the plan.

The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this plan , including the ongoing operation and maintenance of all best management practices (BMPs), and will ensure that this plan is amended as appropriate to reflect up-to-date conditions on the site consistent with the current Orange County Drainage Area Management Plan (DAMP) and the intent of the non-point source NPDES Permit for Waste Discharge Requirements for the County of Orange, Orange County Flood Control District and the incorporated Cities of Orange County within the Santa Ana Region. Once the undersigned transfers its interest in the property, its successors-in-interest shall bear the aforementioned responsibility to implement and amend the WQMP. An appropriate number of approved and signed copies of this document shall be available on the subject site in perpetuity.

Owner: Costco Wholesale
Title Pari Holliday, Development Director
Company Costco Wholesale
Address 9 Corporate Park, Suite 300, Irvine, CA 92606
Email [email protected]
Telephone # (760) 707-9124
I understand my responsibility to implement the provisions of this WQMP including the ongoing operation and maintenance of the best management practices (BMPs) described herein.

Owner
Signature Date
Project Owner’s Certification
Planning Application No.
(If applicable) SDP 05-25-5800 Grading Permit No. TBD
Tract/Parcel Map and
Lot(s) No.

Building Permit No. TBD
Address of Project Site and APN
26602 Towne Centre Drive, Foothill Ranch, CA
612-093-13
(If no address, specify Tract/Parcel Map and Lot Numbers) Item: 11
1593
Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Owner’s Certification
Costco Foothill Ranch WQMP November 2025 Page ii
Preparer (Engineer): Ahmed Zuwawa, PE
Title Professional Engineer PE Registration # C92059
Company Kimley-Horn and Associates,Inc
Address 1100 W Town and Counry Rd, Suite 700, Orange, CA 92868 Email [email protected]
Telephone # (714) 705-1366
I hereby certify that this Water Quality Management Plan is in compliance with, and meets the requirements set forth in, Order No. R8-2009-0030/NPDES No. CAS618030, of the Santa Ana Regional Water Quality Control Board.

Preparer
Signature Date
Place
Stamp
Here
Item: 11
1594
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Table of Contents
Costco Foothill Ranch WQMP November 2025 Page iii
Contents Page No.

Section I Permit(s) and Water Quality Conditions of Approval or Issuance........... 1 Section II Project Description .................................................................................... 3 Section III Site Description.......................................................................................... 8 Section IV Best Management Practices (BMPs) ....................................................... 10 Section V Inspection/Maintenance Responsibility for BMPs ................................. 24 Section VI BMP Exhibit (Site Plan) ........................................................................... 26 Section VII Attachments............................................................................................. 27 Attachments
Attachment A ...................................................................................................Site Map Attachment B ................................................................................................HCOC MAP Attachment C ............................................................................................. Calculations Attachment D ........................................................................................BMP Fact Sheet Attachment E ................................................................................Geotechnical Report Attachment F ..............................................................................Educational Materials Item: 11
1595
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section I
Costco Foothill Ranch WQMP November 2025 Page 1
Section I Permit(s) and Water Quality Conditions of Approval or Issuance
Provide discretionary or grading/building permit information and water quality conditions of approval, or permit issuance, applied to the project. If conditions are unknown, please request applicable conditions from staff. Refer to Section 2.1 in the Technical Guidance Document (TGD) available on the OC Planning website (ocplanning.net).

Project Infomation
Permit/Application No.
(If applicable) SDP-05-25-5800
Grading or Building
Permit No.
(If applicable)
TBD
Address of Project Site (or
Tract Map and Lot
Number if no address)
and APN
26602 Towne Centre Dr, Foothill Ranch, CA 92610
612-093-13
Water Quality Conditions of Approval or Issuance
Water Quality
Conditions of Approval
or Issuance applied to
this project.
(Please list verbatim.)
The project is subject to the water quality conditions set forth by the City of Lake Forest Municipal Code (15.14.040), which requires all construction projects, new development and significant redevelopment with the City to be undertaken in accordance with the best management practices for pollution prevention, the City’s NPDES permit for discharges into and from its MS4, the DAMP, and any other conditions, requirements and water quality management plans adopted by the City.

Conceptual WQMP
Was a Conceptual Water
Quality Management Plan
previously approved for
this project?
No
Item: 11
1596
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section I
Costco Foothill Ranch WQMP November 2025 Page 2
Watershed-Based Plan Conditions
Provide applicable
conditions from watershed -
based plans including
WIHMPs and TMDLS.

Applicable TMDLs are Indicator Bacteria found in Serrano Creek, San Diego Reach 2, and San Diego Reach 1.

Item: 11
1597
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section II
Costco Foothill Ranch WQMP November 2025 Page 3
Section II Project Description
II.1 Project Description
Provide a detailed project description including:
• Project areas;
• Land uses;
• Land cover;
• Design elements;
• A general description not broken down by drainage management areas (DMAs).

Include attributes relevant to determining applicable source controls. Refer to Section 2.2 in the Technical Guidance Document (TGD) for information that must be included in the project description.

Description of Proposed Project
Development Category
(From Model WQMP,
Table 7.11-2; or -3):

Retail Business
Project Area (ft2): 709,157 Number of Dwelling Units: _____0_____ SIC Code: 5399 Project Area
Pervious Impervious
Area
(acres or sq ft)
Percentage
Area
(acres or sq ft)
Percentage
Pre-Project Conditions 38,180 sq ft 5% 670,976 sq ft 95% Post-Project Conditions 46,721 sq ft 7% 662,435 sq ft 93% Drainage
Patterns/Connections
Item: 11
1598
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section II
Costco Foothill Ranch WQMP November 2025 Page 4
Narrative Project
Description:
(Use as much space as
necessary.)
Project scope includes the demolition of approximately 16.3 acres of the existing asphalt pavement and landscaping, and removal of one (1) building located within the Foothill Towne Center. Proposed improvements include construction of a new ground up Wholesale Membership Warehouse Building. The 35-foot-tall building will have a footprint of approximately 161,295 square feet with architectural enhancements.

The parking lot will consist of mainly surface parking and landscape planters.

Existing underground utilities will also be removed to install new underground utilities to meet the project site demands as it relates to stormwater, domestic water, fire water, sanitary sewer, and dry utilities.

The existing site is currently draining to the south towards existing catch basins and valley gutters. In proposed conditions, the site will continue to mainly drain to the south where water will be captured by grate inlet or catch basins and piped to our proposed EcoStream systems. From there the treated water will then be piped to our detention basin and overflow will connect to the existing onsite storm drain system.

Item: 11
1599
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section II
Costco Foothill Ranch WQMP November 2025 Page 5
II.2 Potential Stormwater Pollutants
Determine and list expected stormwater pollutants based on land uses and site activities. Refer to Section 2.2.2 and Table 2.1 in the Technical Guidance Document (TGD) for guidance.

Pollutants of Concern
Pollutant
Check One for
each:

E=Expected to
be of concern
N=Not Expected
to be of concern
Additional Information and Comments
Suspended-Solid/ Sediment E N
Driveways, rooftops, sidewalks, paved areas,
and landscape
Nutrients E N Fertilizers, food waste, and garbage
Heavy Metals E N Cars, trucks and parking areas
Pathogens (Bacteria/Virus) E N Wld Birds and Pet Waste, Garbage Pesticides E N Landscape Area
Oil and Grease E N Leaking vehicles and Parking areas
Toxic Organic Compounds E N Cars and truck
Trash and Debris E N Parking Areas
II.3 Hydrologic Conditions of Concern
Determine if streams located downstream from the project area are potentially susceptible to hydromodification impacts. Refer to Section 2.2.3.1 in the Technical Guidance Document (TGD) for North Orange County or Section 2.2.3.2 for South Orange County.

Item: 11
1600
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section II
Costco Foothill Ranch WQMP November 2025 Page 6
No – Show map
Yes – Describe applicable hydrologic conditions of concern below. Refer to Section 2.2.3 in the Technical Guidance Document (TGD).

HCOCs are considered to exist if any streams located downstream from the project are determined to e potentially susceptible to hydromodification impacts and either of the following conditions exist:
1) Post-development runoff volume for the 2-yr, 24-hr storm event exceeds the pre-development runoff volume for the 2-yr, 24-hr storm by more than 5 percent. 2) Time of concentration of post-development runoff for the 2-yr, 24-hr event exceeds time of the concentration of the pre-development conditions for the 2-yr, 24-hr storm event by more than 5 percent.

Provide values and results to determine if an HCOC exist. Reference Attachment C for calculations.

II.4 Post Development Drainage Characteristics
Describe post development drainage characteristics. Refer to Section 2.2.4 in the Technical Guidance Document (TGD).

Post conditions are designed such that stormwater runoff goes to nearby inlets that route to the EcoStream for treatment. Treated runoff goes to a detention system for peak flow mitigation prior to being discharged into the existing storm drain system. The existing storm drain system eventually outfalls to Serrano Creek to San Diego Reach 2 to San Diego Reach 1 to Newport Bay upper to Newport Bay, lower. There is no offsite run-on for this site due to existing curb and gutter systems and slope of our site and surrounding sites.

Item: 11
1601
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section II
Costco Foothill Ranch WQMP November 2025 Page 7
II.5 Property Ownership/Management
Describe property ownership/management. Refer to Section 2.2.5 in the Technical Guidance Document (TGD).

The maintenance of the proposed development is the responsibility of the owner until the property is sold to a new owner and then they assume responsibility of the BMP maintenance and management. There is no homeowner’s or property owner’s association set up for this proposed development. All of the BMP’s are the responsibility of the owner to maintain. BMPs include but are not limited to BMP maintenance, e.g. inspection, storm drain stenciling, efficient irrigation and landscape maintenance, BMP maintenance of infiltration systems, and junction structures.

No infrastructure will be transferred to a public agency after project completion.

Owner: Costco Wholesale
Owner Contact: Pari Holliday
9 Corporate Park, Suite 230
Irvine, CA 92606
[email protected]
760-707-9124
Item: 11
1602
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch

COSTCO WHOLESALE Section III
Costco Foothill Ranch WQMP November 2025 Page 8
Section III Site Description
III.1 Physical Setting
Fill out table with relevant information. Refer to Section 2.3.1 in the Technical Guidance Document (TGD).

Name of Planned
Community/Planning
Area (if applicable)
FOOTHILL RANCH SPC, TOWNE CENTRE – COSTCO

WHOLESALE
Location/Address
26602 Towne Centre Dr
Foothill Ranch, CA 92610
General Plan Land Use
Designation Retail Business
Zoning Mixed Use 43 (MU 43)
Acreage of Project Site 15.93
Predominant Soil Type Type C
III.2 Site Characteristics
Fill out table with relevant information and include information regarding BMP sizing, suitability, and feasibility, as applicable. Refer to Section 2.3.2 in the Technical Guidance Document (TGD).

Site Characteristics
Precipitation Zone The 85th percentile storm depth = 0.23in Topography
The site is currently designed to be flat with no steep slopes.

The site elevation ranges approximately from 775.00 to 785.00.

Item: 11
1603
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section III
Costco Foothill Ranch WQMP November 2025 Page 9
Drainage
Patterns/Connections
Site currently draining to the south where it ultimately outfalls to Serrano Creek. From Serrano Creek, the storm water drains to San Diego Reach 2, to San Diego Reach 1, to Newport bay upper, to Newport bay lower.

Soil Type, Geology, and
Infiltration Properties Majority soil type C, and does not infiltrate Hydrogeologic
(Groundwater)
Conditions
Per Geotechnical study, ground water was not encountered for 49.5 feet depth.

Geotechnical Conditions
(relevant to infiltration) Per Geotechnical study, the site cannot infiltrate.

Off-Site Drainage Due to existing grades, the site does not receive any offsite runon.

Utility and Infrastructure
Information
Existing project site has inlets around the site to collect storm water runoff, where the water is piped southward towards neighboring storm drain system.

Project proposes new utilities for water, electric, telecom, gas, irrigation water, fire water, sanitary sewer, and storm water. The new storm drain line, similar existing, captures storm water run off with proposed grate inlets around the site. This then gets piped to proposed EcoStreams for treatment and then pipe to a detention system. From the detention system the water is piped to join the existing system.

III.3 Watershed Description
Fill out table with relevant information and include information regarding BMP sizing, suitability, and feasibility, as applicable. Refer to Section 2.3.3 in the Technical Guidance Document (TGD).

Receiving Waters Serrano Creek, San Diego Reach 2, San Diego Reach 1, Newport Bay Upper, Newport Bay Lower
303(d) Listed Impairments
Serrano Creek
• Ammonia (Unionized), Benthic Community Effects, Indicator Bacteria, Toxicity, pH
San Diego Reach 2
• Benthic Community Effects, Indicator Bacteria, Nutrients, sedimentation/Siltation, Toxicity
San Diego Reach 1
Item: 11
1604
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section III
Costco Foothill Ranch WQMP November 2025 Page 10
• Benthic Community Effects, DDT
(Dichlorodiphenyltrichloroethane), Indicator Bacteria, Malathion, Nutrients, Sedimentation/Siltation, Selenium, Toxaphene, Toxicity Newport Bay Upper
• Chlordane, copper, DDT (Dichlorodiphenyltrichloroethane), Indicator Bacteria, Malathion, Nutrients, PCBs (polychlorinated biphenyl), sedimentation/siltation, toxicity
Newport Bay Lower
• Chlordane, copper, DDT (Dichlorodiphenyltrichloroethane), indicator bacteria, nutrients, PCBs (polychlorinated biphenyl), toxicity
Applicable TMDLs
Serrano Creek – Indicator Bacteria
San Diego Reach 2 – Indicator Bacteria
San Diego Reach 1 – Indicator Bacteria
Pollutants of Concern for
the Project San Diego Reach 1 – Bacteria Indicators/pathogens Environmentally Sensitive
and Special Biological
Significant Areas
N/A, project site does not fall within the project category.

Item: 11
1605
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 11
Section IV Best Management Practices (BMPs)
IV. 1 Project Performance Criteria
Describe project performance criteria. Several steps must be followed in order to determine what performance criteria will apply to a project. These steps include:
• If the project has an approved WIHMP or equivalent, then any watershed specific criteria must be used and the project can evaluate participation in the approved regional or subregional opportunities. (Please ask your assigned planner or plan checker regarding whether your project is part of an approved WIHMP or equivalent.) • Determine applicable hydromodification control performance criteria. Refer to Section 7.II2.4.2.2 of the Model WQMP. • Determine applicable LID performance criteria. Refer to Section 7.II-2.4.3 of the Model WQMP. • Determine applicable treatment control BMP performance criteria. Refer to Section 7.II-3.2.2 of the Model WQMP.
• Calculate the LID design storm capture volume for the project. Refer to Section 7.II-2.4.3 of the Model WQMP.
(NOC Permit Area only) Is there an approved WIHMP or equivalent for the project area that includes more stringent LID feasibility criteria or if there are opportunities identified for implementing LID on regional or sub-regional basis?
YES NO
If yes, describe WIHMP
feasibility criteria or
regional/sub-regional LID
opportunities.

N/A
Item: 11
1606
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 12
Project Performance Criteria
If HCOC exists,
list applicable
hydromodification
control
performance
criteria (Section

7.II-2.4.2.2 in
MWQMP)
-On-site / Distributed Controls
- Detention / Retention Basin
-in-stream controls
-drop structures
-grade control structures
-bed and bank reinforcements
-Project is located within an area that is exempt from hydromodification.

List applicable LID
performance
criteria (Section

7.II-2.4.3 from
MWQMP)
Infiltration BMPs, bioinfiltration systems (engineered landscaped areas that promote infiltration but include underdrains), harvest and use systems, green roofs, biofiltration systems (e.g., bioretention with underdrains, vegetated swales) and regional constructed wetland treatment systems.

To meet the performance criteria, the project proposes a detention basin to mitigate peak flows.

List applicable
treatment control
BMP performance
criteria (Section

7.II-3.2.2 from
MWQMP)
Treatment control BMPs are structural, engineered facilities that are designed to remove pollutants from stormwater runoff using treatment processes that do not incorporate significant biological methods
-Sand Filters (media bed filters)
- Cartridge Media Filters
To meet the performance criteria, the project proposes 4 Ecostreams to treat storm water runoff.

Calculate LID
design storm
capture volume
for Project.

Refer to Worksheet B in the Appendix for calculations of DCV.

DMA A DCV = 39,147 cu-ft
DMA B DCV = 8,873 cu-ft
Total DCV = 48,020 cu-ft
The project proposes to use flow based BMPs to treat the storm water runoff. For DMA A we are proposing 3 Ecostreams ( ES128E) to treat the combined peak flow of 2.61. For DMA B we are proposing 1 Ecostream (ES96E) to treat the peak flow of 0.59.

Item: 11
1607
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 13
IV.2. Site Design and Drainage
Describe site design and drainage including
• A narrative of site design practices utilized or rationale for not using practices; • A narrative of how site is designed to allow BMPs to be incorporated to the MEP • A table of DMA characteristics and list of LID BMPs proposed in each DMA. • Reference to the WQMP “BMP Exhibit.”
• Calculation of Design Capture Volume (DCV) for each drainage area. • A listing of GIS coordinates for LID and Treatment Control BMPs.

Refer to Section 2.4.2 in the Technical Guidance Document (TGD).

The site was designed to try and maintain the existing drainage conditions. The site was split into 2 sub DMAs where the water sheet flows to proposed grate inlets and catch basins. DMA A’s water is piped to EcoStream#1- 3 in parallel for treatment then piped to the proposed detention basin. DMA B’s water is piped to EcoStream#4 for treatment and then piped to the same proposed detention basin. The proposed detention basin was designed to mitigate peak flow, where it will ultimately discharge into the existing onsite storm drain system. *Pending more information on existing storm drain system* Item: 11
1608
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 14
IV.3 LID BMP Selection and Project Conformance Analysis Each sub-section below documents that the proposed design features conform to the applicable project performance criteria via check boxes, tables, calculations, narratives, and/or references to worksheets. Refer to Section 2.4.2.3 in the Technical Guidance Document (TGD) for selecting LID BMPs and Section 2.4.3 in the Technical Guidance Document (TGD) for conducting conformance analysis with project performance criteria.

IV.3.1 Hydrologic Source Controls (HSCs)
If required HSCs are included, fill out applicable check box forms. If the retention criteria are otherwise met with other LID BMPs, include a statement indicating HSCs not required.

Name Included?
Localized on-lot infiltration
Impervious area dispersion (e.g. roof top
disconnection)
Street trees (canopy interception)
Residential rain barrels (not actively managed)
Green roofs/Brown roofs
Blue roofs
Impervious area reduction (e.g. permeable
pavers, site design)
Other:

Other:

Item: 11
1609
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 15
IV.3.2 Infiltration BMPs
Identify infiltration BMPs to be used in project. If design volume cannot be met, state why.

Name Included?
Bioretention without underdrains
Rain gardens
Porous landscaping
Infiltration planters
Retention swales
Infiltration trenches
Infiltration basins
Drywells
Subsurface infiltration galleries
French drains
Permeable asphalt
Permeable concrete
Permeable concrete pavers
Other:

Other:

Show calculations below to demonstrate if the LID Design Strom Capture Volume can be met with infiltration BMPs. If not, document how much can be met with infiltration and document why it is not feasible to meet the full volume with infiltration BMPs.

Item: 11
1610
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 16
Per geotechnical report, infiltration is deemed to be infeasible.

IV.3.3 Evapotranspiration, Rainwater Harvesting BMPs
If the full Design Storm Capture Volume cannot be met with infiltration BMPs, describe any evapotranspiration and/or rainwater harvesting BMPs included.

Show calculations below to demonstrate if the LID Design Storm Capture Volume can be met with evapotranspiration and/or rainwater harvesting BMPs in combination with infiltration BMPs. If not, document below how much can be met with either infiltration BMPs, evapotranspiration, rainwater harvesting BMPs, or a combination, and document why it is not feasible to meet the full volume with these BMP categories.

No harvest/reuse is proposed. The detention basin is only used to mitigate peak flow.

Item: 11
1611
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 17
IV.3.4 Biotreatment BMPs
If the full Design Storm Capture Volume cannot be met with infiltration BMPs, and/or evapotranspiration and rainwater harvesting BMPs, describe biotreatment BMPs included. Include sections for selection, suitability, sizing, and infeasibility, as applicable.

Name Included?
Bioretention with underdrains
Stormwater planter boxes with underdrains
Rain gardens with underdrains
Constructed wetlands
Vegetated swales
Vegetated filter strips
Proprietary vegetated biotreatment systems
Wet extended detention basin
Dry extended detention basins
Other:

Other:

Show calculations below to demonstrate if the LID Design Storm Capture Volume can be met with infiltration, evapotranspiration, rainwater harvesting and/or biotreatment BMPs. If not, document how much can be met with either infiltration BMPs, evapotranspiration, rainwater harvesting BMPs, or a combination, and document why it is not feasible to meet the full volume with these BMP categories.

Using AES to determine pre- and post- conditions of our site, we were able to determine that we needed to retain about 0.77 cfs from the 100-year storm. We based our calculations off this to mitigate the peak flow. Prior to entering the basin, the water will be treated through the respective EcoStream. DMA A will use 3 Ecostreams (ES128E) to treat the flow of 2.61 and DMA B will use 1 Ecostream (ES96E) to treat the flow of 0.59. Please refer to Attachment C – Calculations for more information.

Item: 11
1612
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 18
IV.3.5 Hydromodification Control BMPs
Describe hydromodification control BMPs. See Section 5 of the Technical Guidance Document (TGD).

Include sections for selection, suitability, sizing, and infeasibility, as applicable. Detail compliance with Prior Conditions of Approval (if applicable).

Hydromodification Control BMPs
BMP Name BMP Description
Underground detention system MC-3500 ADS
IV.3.6 Regional/Sub-Regional LID BMPs
Describe regional/sub-regional LID BMPs in which the project will participate. Refer to Section 7.II2.4.3.2 of the Model WQMP.

Regional/Sub-Regional LID BMPs
N/A
Item: 11
1613
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 19
IV.3.7 Treatment Control BMPs
Treatment control BMPs can only be considered if the project conformance analysis indicates that it is not feasible to retain the full design capture volume with LID BMPs. Describe treatment control BMPs including sections for selection, sizing, and infeasibility, as applicable.

Treatment Control BMPs
BMP Name BMP Description
EcoStream #1 ADS Ecostream Model # ES128E
EcoStream #2 ADS Ecostream Model # ES128E
Ecostream #3 ADS Ecostream Model # ES128E
EcoStream #4 ADS Ecostream Model # ES96E
Item: 11
1614
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 20
IV.3.8 Non-structural Source Control BMPs
Fill out non-structural source control check box forms or provide a brief narrative explaining if nonstructural source controls were not used.

Non-Structural Source Control BMPs
Identifier Name
Check One
If not applicable, state brief
reason Included Not
Applicable
N1 Education for Property Owners,
Tenants and Occupants
N2 Activity Restrictions
N3 Common Area Landscape
Management
N4 BMP Maintenance
N5 Title 22 CCR Compliance (How
development will comply)
N6 Local Industrial Permit Compliance
N7 Spill Contingency Plan
N8 Underground Storage Tank
Compliance
No proposed underground
storage tank.

N9 Hazardous Materials Disclosure
Compliance
No proposed hazardous
material on site.

N10 Uniform Fire Code Implementation
N11 Common Area Litter Control
N12 Employee Training
N13 Housekeeping of Loading Docks
N14 Common Area Catch Basin Inspection
N15 Street Sweeping Private Streets and
Parking Lots
N16
Retail Gasoline Outlets
No proposed fuel station for
this site.

Item: 11
1615
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 21
IV.3.9 Structural Source Control BMPs
Fill out structural source control check box forms or provide a brief narrative explaining if structural source controls were not used.

Structural Source Control BMPs
Identifier Name
Check One
If not applicable, state brief
reason Included Not
Applicable
S1 Provide storm drain system stenciling
and signage
S2
Design and construct outdoor material
storage areas to reduce pollution
introduction
No outdoor storage areas are
proposed.

S3
Design and construct trash and waste
storage areas to reduce pollution
introduction
S4
Use efficient irrigation systems &
landscape design, water conservation,
smart controllers, and source control
S5 Protect slopes and channels and
provide energy dissipation
There are no steep slopes on the
site.

Incorporate requirements applicable to
individual priority project categories
(from SDRWQCB NPDES Permit)
S6 Dock areas
S7 Maintenance bays
The project will not have
maintenance bays.

S8 Vehicle wash areas
The project will not have vehicle
washing
S9 Outdoor processing areas
The project will not have outdoor
processing areas.

S10 Equipment wash areas
The project will not include
equipment wash areas.

S11 Fueling areas
The project will not include fueling
areas.

S12 Hillside landscaping
There are no areas with steep
slopes onsite
S13 Wash water control for food
preparation areas
S14 Community car wash racks
There are no community car wash
racks onsite.

Item: 11
1616
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 22
IV.4 Alternative Compliance Plan (If Applicable) – N/A
Describe an alternative compliance plan (if applicable). Include alternative compliance obligations (i.e., gallons, pounds) and describe proposed alternative compliance measures. Refer to Section 7.II

3.0 in the WQMP.

IV.4.1 Water Quality Credits
Determine if water quality credits are applicable for the project. Refer to Section 3.1 of the Model WQMP for description of credits and Appendix VI of the Technical Guidance Document (TGD) for calculation methods for applying water quality credits.

Description of Proposed Project
Project Types that Qualify for Water Quality Credits (Select all that apply): N/A Redevelopment
projects that reduce the
overall impervious
footprint of the project
site.

Brownfield redevelopment, meaning
redevelopment, expansion, or reuse of real
property which may be complicated by the
presence or potential presence of hazardous
substances, pollutants or contaminants, and
which have the potential to contribute to
adverse ground or surface WQ if not
redeveloped.

Higher density development projects which
include two distinct categories (credits can only
be taken for one category): those with more
than seven units per acre of development (lower
credit allowance); vertical density
developments, for example, those with a Floor
to Area Ratio (FAR) of 2 or those having more
than 18 units per acre (greater credit allowance).

Mixed use development, such as a
combination of residential, commercial,
industrial, office, institutional, or other land
uses which incorporate design principles that
can demonstrate environmental benefits that
would not be realized through single use
projects (e.g. reduced vehicle trip traffic with
the potential to reduce sources of water or air
pollution).

Transit-oriented developments, such as a
mixed use residential or commercial area
designed to maximize access to public
transportation; similar to above criterion, but
where the development center is within one
half mile of a mass transit center (e.g. bus, rail,
light rail or commuter train station). Such
projects would not be able to take credit for
both categories, but may have greater credit
assigned
Redevelopment projects
in an established historic
district, historic
preservation area, or similar
significant city area
including core City Center
areas (to be defined through
mapping).

Developments with
dedication of
undeveloped portions to
parks, preservation
areas and other pervious
uses.

Developments
in a city center
area.

Developments
in historic
districts or
historic
preservation
areas.

Live-work
developments, a variety of
developments designed to
support residential and
vocational needs together –
similar to criteria to mixed
use development; would not
be able to take credit for
both categories.

In-fill projects, the
conversion of empty lots
and other underused spaces
into more beneficially used
spaces, such as residential
or commercial areas.

Item: 11
1617
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section IV
Costco Foothill Ranch WQMP November 2025 Page 23
Calculation of
Water Quality
Credits
(if applicable)
N/A
IV.4.2 Alternative Compliance Plan Information
Describe an alternative compliance plan (if applicable). Include alternative compliance obligations (i.e., gallons, pounds) and describe proposed alternative compliance measures. Refer to Section 7.II

3.0 in the Model WQMP.

N/A
Item: 11
1618
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section V
Costco Foothill Ranch WQMP November 2025 Page 24
Section V Inspection/Maintenance Responsibility for BMPs Fill out information in table below. Prepare and attach an Operation and Maintenance Plan. The owner will be responsible for funding the maintenance of the BMPs. Inspection and maintenance records must be kept for a minimum of five years for inspection by the regulatory agencies. Refer to Section 7.II 4.0 in the Model WQMP.

BMP Inspection/Maintenance
BMP
Reponsible
Party(s)
Inspection/
Maintenance
Activities
Required
Minimum
Frequency of
Activities
MWS #1-3
ADS – ECOSTREAM
ES128E

PARI HOLLIDAY

COSTCO WHOLESALE
9 CORPORATE PARK,
SUITE 230, IRVINE,
CA 92606
(760) 707-9124
Inspect manhole for
trash/debris and
replace mulch.

See manufacturer
recommendations in
O&M plan for more
information.
48 HOURS AFTER
STORM EVENT / 6

MONTH PERIOD
MWS #4

ADS-ECOSTREAM
ES96E

PARI HOLLIDAY

COSTCO WHOLESALE
9 CORPORATE PARK,
SUITE 230, IRVINE,
CA 92606
(760) 707-9124
Inspect manhole for
trash/debris and
replace mulch.

See manufacturer
recommendations in
O&M plan for more
information.
48 HOURS AFTER
STORM EVENT / 6

MONTH PERIOD
Item: 11
1619
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VI
Costco Foothill Ranch WQMP November 2025 Page 25
Section VI BMP Exhibit (Site Plan)
VI.1 BMP Exhibit (Site Plan)
Include a BMP Exhibit (Site Plan), at a size no less than 24” by 36,” which includes the following minimum information:
• Insert in the title block (lower right hand corner) of BMP Exhibit: the WQMP Number (assigned by staff) and the grading/building or Planning Application permit numbers • Project location (address, tract/lot number(s), etc.) • Site boundary
• Land uses and land covers, as applicable
• Suitability/feasibility constraints
• Structural BMP locations
• Drainage delineations and flow information
• Delineate the area being treated by each structural BMP • GIS coordinates for LID and Treatment Control BMPs
• Drainage connections
• BMP details
• Preparer name and stamp
Please do not include any areas outside of the project area or any information not related to drainage or water quality. The approved BMP Exhibit (Site Plan) shall be submitted as a plan sheet on all grading and building plan sets submitted for plan check review and approval. The BMP Exhibit shall be at the same size as the rest of the plan sheets in the submittal and shall have an approval stamp and signature prior to plan check submittal.

VI.2 Submittal and Recordation of Water Quality Management Plan Following approval of the Final Project-Specific WQMP, three copies of the approved WQMP (including BMP Exhibit, Operations and Maintenance (O&M) Plan, and Appendices) shall be submitted. In addition, these documents shall be submitted in a PDF format.

Each approved WQMP (including BMP Exhibit, Operations and Maintenance (O&M) Plan, and Appendices) shall be recorded in the Orange County Clerk-Recorder’s Office, prior to close-out of grading and/or building permit. Educational Materials are not required to be included.

Item: 11
1620
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 26
Section VII Educational Materials (To Be Prepared in Final Engineering) Refer to the Orange County Stormwater Program (ocwatersheds.com) for a library of materials available. Please only attach the educational materials specifically applicable to this project. Other materials specific to the project may be included as well and must be attached.

Education Materials
Residential Material
(http://www.ocwatersheds.com)
Check If
Applicable
Business Material
(http://www.ocwatersheds.com)
Check If
Applicable
The Ocean Begins at Your Front Door Tips for the Automotive Industry Tips for Car Wash Fund-raisers Tips for Using Concrete and Mortar Tips for the Home Mechanic Tips for the Food Service Industry Homeowners Guide for Sustainable
Water Use
Proper Maintenance Practices for Your
Business
Household Tips
Other Material
Check If
Attached Proper Disposal of Household
Hazardous Waste
Recycle at Your Local Used Oil
Collection Center (North County)
Recycle at Your Local Used Oil
Collection Center (Central County)
Recycle at Your Local Used Oil
Collection Center (South County)
Tips for Maintaining a Septic Tank
System
Responsible Pest Control
Sewer Spill
Tips for the Home Improvement
Projects
Tips for Horse Care
Tips for Landscaping and Gardening
Tips for Pet Care
Tips for Pool Maintenance
Tips for Residential Pool, Landscape
and Hardscape Drains
Tips for Projects Using Paint
Item: 11
1621
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 27
Attachment A – Site Plan
Item: 11
1622
v v v ENTRY EXIT
RESTRICTED ELECTRIC VEHICLES ONLY RESTRICTED ELECTRIC VEHICLES ONLY v A 12.92 B 3.01 HYDROLOGY INFORMATION LEGEND X XXX COSTCO - FOOTHILL RANCH POST-DEVELOPMENT WQMP EXHIBIT © TOWNE CENTRE AND MARKET 1 DRAINAGE NOTES NORTH Know what's before you dig. below. Call 811 R WQMP SUMMARY Δ

TOWNE CENTRE DR

MARKET (PRIVATE ROAD)

FOOTHILL TRANSPORTATION CORRIDOR
1623
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 28
Attachment B – HCOC MAP
Item: 11
1624

APPROXIMATE

PROJECTLOCATION
1625
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 29
HCOC Calculation Summary Table
TC2-YEAR (Min) Q2-YEAR(CFS) V2-YEAR,24-HOUR (CF)
Pre-Development 9.03 23.72 96,268
Post-Development 9.51 24.04 104,108
HCOC Requirment
(0.95*Post-Pre)
N/A

0.88 (Amount of runoff to
mitigate)
2,635
(Required Retention)
Basin Requirement - 23.16 2,635
Post-Development
Condition with BMPs - - 3,332
Item: 11
1626
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 30
Attachment C – Calculations
Item: 11
1627
Item: 11
1628
Item: 11
1629
Item: 11
1630
Item: 11
1631
Item: 11
1632
Item: 11
1633
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
(c) Copyright 1983-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* EXISTING 2 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRME2YR.DAT
TIME/DATE OF STUDY: 11:11 09/17/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 2.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) I ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1634
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 314.00
ELEVATION DATA: UPSTREAM(FEET) = 783.30 DOWNSTREAM(FEET) = 775.81 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.399
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.965
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.45 0.25 0.100 50 6.40
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.53
TOTAL AREA(ACRES) = 1.45 PEAK FLOW RATE(CFS) = 2.53
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 301.00
ELEVATION DATA: UPSTREAM(FEET) = 787.52 DOWNSTREAM(FEET) = 782.97 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.893
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.883
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.04 0.25 0.100 50 6.89
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 3.41
TOTAL AREA(ACRES) = 2.04 PEAK FLOW RATE(CFS) = 3.41
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 782.97 DOWNSTREAM(FEET) = 776.77 CHANNEL LENGTH THRU SUBAREA(FEET) = 301.00 CHANNEL SLOPE = 0.0206 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
Item: 11
1635
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.634
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 4.14 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 6.41
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.60 AVERAGE FLOW DEPTH(FEET) = 0.13 TRAVEL TIME(MIN.) = 1.93 Tc(MIN.) = 8.82
SUBAREA AREA(ACRES) = 4.14 SUBAREA RUNOFF(CFS) = 6.00
EFFECTIVE AREA(ACRES) = 6.18 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.2 PEAK FLOW RATE(CFS) = 8.95
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.16 FLOW VELOCITY(FEET/SEC.) = 2.82
LONGEST FLOWPATH FROM NODE 2.10 TO NODE 2.30 = 602.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 189.00
ELEVATION DATA: UPSTREAM(FEET) = 782.48 DOWNSTREAM(FEET) = 778.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.268
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.197
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.58 0.25 0.100 50 5.27
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 3.09
TOTAL AREA(ACRES) = 1.58 PEAK FLOW RATE(CFS) = 3.09
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.16 DOWNSTREAM(FEET) = 774.54 CHANNEL LENGTH THRU SUBAREA(FEET) = 189.00 CHANNEL SLOPE = 0.0192 CHANNEL BASE(FEET) = 85.00 "Z" FACTOR = 99.000
Item: 11
1636
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.809
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.90 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 4.63
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.48 AVERAGE FLOW DEPTH(FEET) = 0.04 TRAVEL TIME(MIN.) = 2.12 Tc(MIN.) = 7.39
SUBAREA AREA(ACRES) = 1.90 SUBAREA RUNOFF(CFS) = 3.05
EFFECTIVE AREA(ACRES) = 3.48 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.5 PEAK FLOW RATE(CFS) = 5.59
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.04 FLOW VELOCITY(FEET/SEC.) = 1.53
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 378.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 329.00
ELEVATION DATA: UPSTREAM(FEET) = 777.53 DOWNSTREAM(FEET) = 776.74 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 10.320
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.493
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.64 0.25 0.100 50 10.32
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 0.85
TOTAL AREA(ACRES) = 0.64 PEAK FLOW RATE(CFS) = 0.85
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.74 DOWNSTREAM(FEET) = 776.52 CHANNEL LENGTH THRU SUBAREA(FEET) = 168.00 CHANNEL SLOPE = 0.0013 Item: 11
1637
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.216
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.23 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.51
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 0.63 AVERAGE FLOW DEPTH(FEET) = 0.13 TRAVEL TIME(MIN.) = 4.45 Tc(MIN.) = 14.77
SUBAREA AREA(ACRES) = 1.23 SUBAREA RUNOFF(CFS) = 1.32
EFFECTIVE AREA(ACRES) = 1.87 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.9 PEAK FLOW RATE(CFS) = 2.00
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.15 FLOW VELOCITY(FEET/SEC.) = 0.69
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 497.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.52 DOWNSTREAM(FEET) = 774.63 CHANNEL LENGTH THRU SUBAREA(FEET) = 272.00 CHANNEL SLOPE = 0.0069 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.085
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.15 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.03
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.40 AVERAGE FLOW DEPTH(FEET) = 0.12 TRAVEL TIME(MIN.) = 3.24 Tc(MIN.) = 18.01
SUBAREA AREA(ACRES) = 2.15 SUBAREA RUNOFF(CFS) = 2.05
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.0 PEAK FLOW RATE(CFS) = 3.83
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.13 FLOW VELOCITY(FEET/SEC.) = 1.56
Item: 11
1638
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 769.00 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 4.0 TC(MIN.) = 18.01
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 3.83
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1639
____________________________________________________________________________ ****************************************************************************

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* EXISTING 100 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRME2YR.DAT
TIME/DATE OF STUDY: 11:21 09/17/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 100.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) III ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1640
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 314.00
ELEVATION DATA: UPSTREAM(FEET) = 783.30 DOWNSTREAM(FEET) = 775.81 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.399
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.371
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.45 0.25 0.100 86 6.40
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 6.98
TOTAL AREA(ACRES) = 1.45 PEAK FLOW RATE(CFS) = 6.98
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 301.00
ELEVATION DATA: UPSTREAM(FEET) = 787.52 DOWNSTREAM(FEET) = 782.97 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.893
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.148
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.04 0.25 0.100 86 6.89
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 9.40
TOTAL AREA(ACRES) = 2.04 PEAK FLOW RATE(CFS) = 9.40
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 782.97 DOWNSTREAM(FEET) = 776.77 CHANNEL LENGTH THRU SUBAREA(FEET) = 301.00 CHANNEL SLOPE = 0.0206 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
Item: 11
1641
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.599
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 4.14 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 17.96
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.35 AVERAGE FLOW DEPTH(FEET) = 0.21 TRAVEL TIME(MIN.) = 1.50 Tc(MIN.) = 8.39
SUBAREA AREA(ACRES) = 4.14 SUBAREA RUNOFF(CFS) = 17.04
EFFECTIVE AREA(ACRES) = 6.18 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.2 PEAK FLOW RATE(CFS) = 25.44
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.24 FLOW VELOCITY(FEET/SEC.) = 3.70
LONGEST FLOWPATH FROM NODE 2.10 TO NODE 2.30 = 602.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 189.00
ELEVATION DATA: UPSTREAM(FEET) = 782.48 DOWNSTREAM(FEET) = 778.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.268
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.005
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.58 0.25 0.100 86 5.27
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 8.50
TOTAL AREA(ACRES) = 1.58 PEAK FLOW RATE(CFS) = 8.50
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.16 DOWNSTREAM(FEET) = 774.54 CHANNEL LENGTH THRU SUBAREA(FEET) = 189.00 CHANNEL SLOPE = 0.0192 CHANNEL BASE(FEET) = 85.00 "Z" FACTOR = 99.000
Item: 11
1642
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.218
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.90 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 12.97
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.15 AVERAGE FLOW DEPTH(FEET) = 0.07 TRAVEL TIME(MIN.) = 1.46 Tc(MIN.) = 6.73
SUBAREA AREA(ACRES) = 1.90 SUBAREA RUNOFF(CFS) = 8.88
EFFECTIVE AREA(ACRES) = 3.48 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.5 PEAK FLOW RATE(CFS) = 16.27
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.07 FLOW VELOCITY(FEET/SEC.) = 2.40
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 378.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 329.00
ELEVATION DATA: UPSTREAM(FEET) = 777.53 DOWNSTREAM(FEET) = 776.74 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 10.320
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.085
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.64 0.25 0.100 86 10.32
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.34
TOTAL AREA(ACRES) = 0.64 PEAK FLOW RATE(CFS) = 2.34
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.74 DOWNSTREAM(FEET) = 776.52 CHANNEL LENGTH THRU SUBAREA(FEET) = 168.00 CHANNEL SLOPE = 0.0013 Item: 11
1643
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 3.476
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.23 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 4.26
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 0.83 AVERAGE FLOW DEPTH(FEET) = 0.20 TRAVEL TIME(MIN.) = 3.36 Tc(MIN.) = 13.68
SUBAREA AREA(ACRES) = 1.23 SUBAREA RUNOFF(CFS) = 3.82
EFFECTIVE AREA(ACRES) = 1.87 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.9 PEAK FLOW RATE(CFS) = 5.81
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.23 FLOW VELOCITY(FEET/SEC.) = 0.90
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 497.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.52 DOWNSTREAM(FEET) = 774.63 CHANNEL LENGTH THRU SUBAREA(FEET) = 272.00 CHANNEL SLOPE = 0.0069 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 3.169
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.15 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 8.85
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.89 AVERAGE FLOW DEPTH(FEET) = 0.19 TRAVEL TIME(MIN.) = 2.40 Tc(MIN.) = 16.07
SUBAREA AREA(ACRES) = 2.15 SUBAREA RUNOFF(CFS) = 6.08
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.0 PEAK FLOW RATE(CFS) = 11.38
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.22 FLOW VELOCITY(FEET/SEC.) = 1.99
Item: 11
1644
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 769.00 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 4.0 TC(MIN.) = 16.07
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 11.38
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1645
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA A 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 1.45
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.250
TIME OF CONCENTRATION(MIN.) = 6.40

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.22
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.03
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0002 0.04 Q . . . .

0.21 0.0006 0.04 Q . . . .

Item: 11
1646

0.32 0.0009 0.04 Q . . . .

0.43 0.0013 0.04 Q . . . .

0.53 0.0017 0.04 Q . . . .

0.64 0.0020 0.04 Q . . . .

0.75 0.0024 0.04 Q . . . .

0.85 0.0028 0.04 Q . . . .

0.96 0.0032 0.04 Q . . . .

1.07 0.0036 0.04 Q . . . .

1.17 0.0039 0.04 Q . . . .

1.28 0.0043 0.04 Q . . . .

1.39 0.0047 0.04 Q . . . .

1.49 0.0051 0.04 Q . . . .

1.60 0.0055 0.04 Q . . . .

1.71 0.0059 0.04 Q . . . .

1.81 0.0063 0.04 Q . . . .

1.92 0.0067 0.04 Q . . . .

2.03 0.0071 0.05 Q . . . .

2.13 0.0075 0.05 Q . . . .

2.24 0.0079 0.05 Q . . . .

2.35 0.0083 0.05 Q . . . .

2.45 0.0087 0.05 Q . . . .

2.56 0.0091 0.05 Q . . . .

2.67 0.0095 0.05 Q . . . .

2.77 0.0099 0.05 Q . . . .

2.88 0.0103 0.05 Q . . . .

2.99 0.0107 0.05 Q . . . .

3.09 0.0112 0.05 Q . . . .

3.20 0.0116 0.05 Q . . . .

3.31 0.0120 0.05 Q . . . .

3.41 0.0124 0.05 Q . . . .

3.52 0.0129 0.05 Q . . . .

3.63 0.0133 0.05 Q . . . .

3.73 0.0137 0.05 Q . . . .

3.84 0.0142 0.05 Q . . . .

3.95 0.0146 0.05 Q . . . .

4.05 0.0150 0.05 Q . . . .

4.16 0.0155 0.05 Q . . . .

4.27 0.0159 0.05 Q . . . .

4.37 0.0164 0.05 Q . . . .

4.48 0.0168 0.05 Q . . . .

4.59 0.0173 0.05 Q . . . .

4.69 0.0177 0.05 Q . . . .

4.80 0.0182 0.05 Q . . . .

4.91 0.0186 0.05 Q . . . .

5.01 0.0191 0.05 Q . . . .

5.12 0.0196 0.05 Q . . . .

5.23 0.0200 0.05 Q . . . .

5.33 0.0205 0.05 Q . . . .

5.44 0.0210 0.05 Q . . . .

5.55 0.0214 0.05 Q . . . .

Item: 11
1647

5.65 0.0219 0.05 Q . . . .

5.76 0.0224 0.05 Q . . . .

5.87 0.0229 0.06 Q . . . .

5.97 0.0234 0.06 Q . . . .

6.08 0.0239 0.06 Q . . . .

6.19 0.0244 0.06 Q . . . .

6.29 0.0249 0.06 Q . . . .

6.40 0.0254 0.06 Q . . . .

6.51 0.0259 0.06 Q . . . .

6.61 0.0264 0.06 Q . . . .

6.72 0.0269 0.06 Q . . . .

6.83 0.0274 0.06 Q . . . .

6.93 0.0279 0.06 Q . . . .

7.04 0.0284 0.06 Q . . . .

7.15 0.0290 0.06 Q . . . .

7.25 0.0295 0.06 Q . . . .

7.36 0.0300 0.06 Q . . . .

7.47 0.0306 0.06 Q . . . .

7.57 0.0311 0.06 Q . . . .

7.68 0.0317 0.06 Q . . . .

7.79 0.0322 0.06 Q . . . .

7.89 0.0328 0.06 Q . . . .

8.00 0.0333 0.06 Q . . . .

8.11 0.0339 0.06 Q . . . .

8.21 0.0345 0.07 Q . . . .

8.32 0.0351 0.07 Q . . . .

8.43 0.0356 0.07 Q . . . .

8.53 0.0362 0.07 Q . . . .

8.64 0.0368 0.07 Q . . . .

8.75 0.0374 0.07 Q . . . .

8.85 0.0380 0.07 Q . . . .

8.96 0.0386 0.07 Q . . . .

9.07 0.0392 0.07 Q . . . .

9.17 0.0398 0.07 Q . . . .

9.28 0.0405 0.07 Q . . . .

9.39 0.0411 0.07 Q . . . .

9.49 0.0417 0.07 Q . . . .

9.60 0.0424 0.07 Q . . . .

9.71 0.0430 0.07 Q . . . .

9.81 0.0437 0.07 Q . . . .

9.92 0.0444 0.08 Q . . . .

10.03 0.0450 0.08 Q . . . .

10.13 0.0457 0.08 Q . . . .

10.24 0.0464 0.08 Q . . . .

10.35 0.0471 0.08 Q . . . .

10.45 0.0478 0.08 Q . . . .

10.56 0.0485 0.08 Q . . . .

10.67 0.0492 0.08 Q . . . .

10.77 0.0499 0.08 Q . . . .

10.88 0.0507 0.08 Q . . . .

Item: 11
1648

10.99 0.0514 0.09 Q . . . .

11.09 0.0522 0.09 Q . . . .

11.20 0.0530 0.09 Q . . . .

11.31 0.0537 0.09 Q . . . .

11.41 0.0545 0.09 Q . . . .

11.52 0.0553 0.09 Q . . . .

11.63 0.0561 0.09 Q . . . .

11.73 0.0570 0.09 Q . . . .

11.84 0.0578 0.10 Q . . . .

11.95 0.0586 0.10 Q . . . .

12.05 0.0595 0.10 Q . . . .

12.16 0.0605 0.12 Q . . . .

12.27 0.0616 0.12 Q . . . .

12.37 0.0627 0.13 Q . . . .

12.48 0.0638 0.13 Q . . . .

12.59 0.0650 0.13 Q . . . .

12.69 0.0661 0.13 Q . . . .

12.80 0.0673 0.13 Q . . . .

12.91 0.0685 0.14 Q . . . .

13.01 0.0697 0.14 Q . . . .

13.12 0.0709 0.14 Q . . . .

13.23 0.0722 0.14 Q . . . .

13.33 0.0735 0.15 Q . . . .

13.44 0.0748 0.15 Q . . . .

13.55 0.0762 0.16 Q . . . .

13.65 0.0775 0.16 Q . . . .

13.76 0.0790 0.16 Q . . . .

13.87 0.0804 0.17 Q . . . .

13.97 0.0819 0.17 Q . . . .

14.08 0.0834 0.18 Q . . . .

14.19 0.0850 0.19 Q . . . .

14.29 0.0867 0.19 Q . . . .

14.40 0.0884 0.20 Q . . . .

14.51 0.0902 0.21 Q . . . .

14.61 0.0921 0.22 Q . . . .

14.72 0.0940 0.22 Q . . . .

14.83 0.0960 0.23 Q . . . .

14.93 0.0981 0.24 Q . . . .

15.04 0.1003 0.26 .Q . . . .

15.15 0.1027 0.27 .Q . . . .

15.25 0.1051 0.29 .Q . . . .

15.36 0.1078 0.31 .Q . . . .

15.47 0.1105 0.30 .Q . . . .

15.57 0.1132 0.32 .Q . . . .

15.68 0.1163 0.39 .Q . . . .

15.79 0.1200 0.44 .Q . . . .

15.89 0.1247 0.63 . Q . . . .

16.00 0.1312 0.86 . Q . . . .

16.11 0.1464 2.58 . Q . . .

16.21 0.1600 0.52 . Q . . . .

Item: 11
1649

16.32 0.1638 0.35 .Q . . . .

16.43 0.1667 0.31 .Q . . . .

16.53 0.1693 0.28 .Q . . . .

16.64 0.1717 0.25 .Q . . . .

16.75 0.1738 0.23 Q . . . .

16.85 0.1757 0.21 Q . . . .

16.96 0.1775 0.20 Q . . . .

17.07 0.1792 0.18 Q . . . .

17.17 0.1807 0.17 Q . . . .

17.28 0.1822 0.16 Q . . . .

17.39 0.1836 0.15 Q . . . .

17.49 0.1849 0.15 Q . . . .

17.60 0.1861 0.14 Q . . . .

17.71 0.1874 0.14 Q . . . .

17.81 0.1885 0.13 Q . . . .

17.92 0.1897 0.13 Q . . . .

18.03 0.1908 0.12 Q . . . .

18.13 0.1917 0.10 Q . . . .

18.24 0.1926 0.09 Q . . . .

18.35 0.1934 0.09 Q . . . .

18.45 0.1942 0.09 Q . . . .

18.56 0.1950 0.09 Q . . . .

18.67 0.1957 0.08 Q . . . .

18.77 0.1965 0.08 Q . . . .

18.88 0.1972 0.08 Q . . . .

18.99 0.1979 0.08 Q . . . .

19.09 0.1986 0.08 Q . . . .

19.20 0.1993 0.08 Q . . . .

19.31 0.1999 0.07 Q . . . .

19.41 0.2006 0.07 Q . . . .

19.52 0.2012 0.07 Q . . . .

19.63 0.2018 0.07 Q . . . .

19.73 0.2024 0.07 Q . . . .

19.84 0.2030 0.07 Q . . . .

19.95 0.2036 0.07 Q . . . .

20.05 0.2042 0.06 Q . . . .

20.16 0.2047 0.06 Q . . . .

20.27 0.2053 0.06 Q . . . .

20.37 0.2059 0.06 Q . . . .

20.48 0.2064 0.06 Q . . . .

20.59 0.2069 0.06 Q . . . .

20.69 0.2074 0.06 Q . . . .

20.80 0.2080 0.06 Q . . . .

20.91 0.2085 0.06 Q . . . .

21.01 0.2090 0.06 Q . . . .

21.12 0.2095 0.06 Q . . . .

21.23 0.2100 0.06 Q . . . .

21.33 0.2104 0.05 Q . . . .

21.44 0.2109 0.05 Q . . . .

21.55 0.2114 0.05 Q . . . .

Item: 11
1650

21.65 0.2119 0.05 Q . . . .

21.76 0.2123 0.05 Q . . . .

21.87 0.2128 0.05 Q . . . .

21.97 0.2132 0.05 Q . . . .

22.08 0.2137 0.05 Q . . . .

22.19 0.2141 0.05 Q . . . .

22.29 0.2145 0.05 Q . . . .

22.40 0.2150 0.05 Q . . . .

22.51 0.2154 0.05 Q . . . .

22.61 0.2158 0.05 Q . . . .

22.72 0.2162 0.05 Q . . . .

22.83 0.2166 0.05 Q . . . .

22.93 0.2170 0.05 Q . . . .

23.04 0.2174 0.05 Q . . . .

23.15 0.2178 0.05 Q . . . .

23.25 0.2182 0.04 Q . . . .

23.36 0.2186 0.04 Q . . . .

23.47 0.2190 0.04 Q . . . .

23.57 0.2194 0.04 Q . . . .

23.68 0.2198 0.04 Q . . . .

23.79 0.2202 0.04 Q . . . .

23.89 0.2205 0.04 Q . . . .

24.00 0.2209 0.04 Q . . . .

24.11 0.2211 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.0
10% 96.0
20% 25.6
30% 12.8
40% 6.4
50% 6.4
60% 6.4
70% 6.4
80% 6.4
90% 6.4
Item: 11
1651
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA B 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 6.28
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 8.82

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.96
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.11
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.12 0.0011 0.18 Q . . . .

0.27 0.0033 0.18 Q . . . .

Item: 11
1652

0.42 0.0055 0.18 Q . . . .

0.57 0.0077 0.18 Q . . . .

0.71 0.0100 0.18 Q . . . .

0.86 0.0122 0.19 Q . . . .

1.01 0.0145 0.19 Q . . . .

1.15 0.0168 0.19 Q . . . .

1.30 0.0191 0.19 Q . . . .

1.45 0.0214 0.19 Q . . . .

1.59 0.0237 0.19 Q . . . .

1.74 0.0261 0.19 Q . . . .

1.89 0.0284 0.19 Q . . . .

2.04 0.0308 0.20 Q . . . .

2.18 0.0332 0.20 Q . . . .

2.33 0.0356 0.20 Q . . . .

2.48 0.0380 0.20 Q . . . .

2.62 0.0404 0.20 Q . . . .

2.77 0.0429 0.20 Q . . . .

2.92 0.0453 0.20 Q . . . .

3.06 0.0478 0.20 Q . . . .

3.21 0.0503 0.21 Q . . . .

3.36 0.0529 0.21 Q . . . .

3.51 0.0554 0.21 Q . . . .

3.65 0.0579 0.21 Q . . . .

3.80 0.0605 0.21 Q . . . .

3.95 0.0631 0.21 Q . . . .

4.09 0.0657 0.22 Q . . . .

4.24 0.0684 0.22 Q . . . .

4.39 0.0710 0.22 Q . . . .

4.53 0.0737 0.22 Q . . . .

4.68 0.0764 0.22 Q . . . .

4.83 0.0791 0.22 Q . . . .

4.98 0.0819 0.23 Q . . . .

5.12 0.0846 0.23 Q . . . .

5.27 0.0874 0.23 Q . . . .

5.42 0.0902 0.23 Q . . . .

5.56 0.0931 0.23 Q . . . .

5.71 0.0959 0.24 Q . . . .

5.86 0.0988 0.24 Q . . . .

6.00 0.1017 0.24 Q . . . .

6.15 0.1046 0.24 Q . . . .

6.30 0.1076 0.24 Q . . . .

6.45 0.1106 0.25 Q . . . .

6.59 0.1136 0.25 Q . . . .

6.74 0.1167 0.25 .Q . . . .

6.89 0.1198 0.25 .Q . . . .

7.03 0.1229 0.26 .Q . . . .

7.18 0.1260 0.26 .Q . . . .

7.33 0.1292 0.26 .Q . . . .

7.47 0.1324 0.27 .Q . . . .

7.62 0.1356 0.27 .Q . . . .

Item: 11
1653

7.77 0.1389 0.27 .Q . . . .

7.92 0.1422 0.27 .Q . . . .

8.06 0.1456 0.28 .Q . . . .

8.21 0.1490 0.28 .Q . . . .

8.36 0.1524 0.28 .Q . . . .

8.50 0.1559 0.29 .Q . . . .

8.65 0.1594 0.29 .Q . . . .

8.80 0.1630 0.30 .Q . . . .

8.94 0.1666 0.30 .Q . . . .

9.09 0.1702 0.30 .Q . . . .

9.24 0.1739 0.31 .Q . . . .

9.39 0.1777 0.31 .Q . . . .

9.53 0.1815 0.31 .Q . . . .

9.68 0.1853 0.32 .Q . . . .

9.83 0.1892 0.32 .Q . . . .

9.97 0.1932 0.33 .Q . . . .

10.12 0.1972 0.33 .Q . . . .

10.27 0.2013 0.34 .Q . . . .

10.41 0.2054 0.34 .Q . . . .

10.56 0.2097 0.35 .Q . . . .

10.71 0.2139 0.35 .Q . . . .

10.85 0.2183 0.36 .Q . . . .

11.00 0.2228 0.37 .Q . . . .

11.15 0.2273 0.38 .Q . . . .

11.30 0.2319 0.38 .Q . . . .

11.44 0.2366 0.39 .Q . . . .

11.59 0.2414 0.40 .Q . . . .

11.74 0.2462 0.41 .Q . . . .

11.88 0.2512 0.41 .Q . . . .

12.03 0.2563 0.43 .Q . . . .

12.18 0.2620 0.51 . Q . . . .

12.32 0.2684 0.54 . Q . . . .

12.47 0.2750 0.55 . Q . . . .

12.62 0.2817 0.56 . Q . . . .

12.77 0.2886 0.57 . Q . . . .

12.91 0.2957 0.59 . Q . . . .

13.06 0.3030 0.60 . Q . . . .

13.21 0.3104 0.62 . Q . . . .

13.35 0.3181 0.64 . Q . . . .

13.50 0.3260 0.66 . Q . . . .

13.65 0.3341 0.68 . Q . . . .

13.80 0.3425 0.71 . Q . . . .

13.94 0.3512 0.72 . Q . . . .

14.09 0.3602 0.77 . Q . . . .

14.24 0.3699 0.81 . Q . . . .

14.38 0.3800 0.86 . Q . . . .

14.53 0.3906 0.89 . Q . . . .

14.68 0.4017 0.95 . Q . . . .

14.82 0.4135 0.98 . Q . . . .

14.97 0.4259 1.07 . Q . . . .

Item: 11
1654

15.12 0.4393 1.12 . Q . . . .

15.27 0.4537 1.26 . Q . . . .

15.41 0.4695 1.34 . Q . . . .

15.56 0.4861 1.38 . Q . . . .

15.71 0.5039 1.56 . Q . . . .

15.85 0.5272 2.26 . Q. . . .

16.00 0.5597 3.09 . . Q . . .

16.15 0.6346 9.25 . . . . Q .

16.29 0.7019 1.83 . Q . . . .

16.44 0.7208 1.29 . Q . . . .

16.59 0.7358 1.19 . Q . . . .

16.73 0.7493 1.03 . Q . . . .

16.88 0.7610 0.91 . Q . . . .

17.03 0.7717 0.83 . Q . . . .

17.18 0.7812 0.74 . Q . . . .

17.32 0.7899 0.69 . Q . . . .

17.47 0.7981 0.65 . Q . . . .

17.62 0.8057 0.61 . Q . . . .

17.76 0.8130 0.58 . Q . . . .

17.91 0.8199 0.56 . Q . . . .

18.06 0.8265 0.53 . Q . . . .

18.20 0.8323 0.42 .Q . . . .

18.35 0.8373 0.40 .Q . . . .

18.50 0.8421 0.39 .Q . . . .

18.65 0.8467 0.37 .Q . . . .

18.79 0.8511 0.36 .Q . . . .

18.94 0.8554 0.35 .Q . . . .

19.09 0.8596 0.34 .Q . . . .

19.23 0.8636 0.33 .Q . . . .

19.38 0.8675 0.32 .Q . . . .

19.53 0.8713 0.31 .Q . . . .

19.67 0.8750 0.30 .Q . . . .

19.82 0.8786 0.29 .Q . . . .

19.97 0.8821 0.29 .Q . . . .

20.12 0.8855 0.28 .Q . . . .

20.26 0.8889 0.27 .Q . . . .

20.41 0.8922 0.27 .Q . . . .

20.56 0.8954 0.26 .Q . . . .

20.70 0.8985 0.26 .Q . . . .

20.85 0.9016 0.25 .Q . . . .

21.00 0.9046 0.25 Q . . . .

21.14 0.9076 0.24 Q . . . .

21.29 0.9105 0.24 Q . . . .

21.44 0.9134 0.23 Q . . . .

21.59 0.9162 0.23 Q . . . .

21.73 0.9189 0.23 Q . . . .

21.88 0.9217 0.22 Q . . . .

22.03 0.9243 0.22 Q . . . .

22.17 0.9270 0.22 Q . . . .

22.32 0.9296 0.21 Q . . . .

Item: 11
1655

22.47 0.9321 0.21 Q . . . .

22.61 0.9346 0.21 Q . . . .

22.76 0.9371 0.20 Q . . . .

22.91 0.9396 0.20 Q . . . .

23.06 0.9420 0.20 Q . . . .

23.20 0.9444 0.20 Q . . . .

23.35 0.9467 0.19 Q . . . .

23.50 0.9491 0.19 Q . . . .

23.64 0.9514 0.19 Q . . . .

23.79 0.9536 0.19 Q . . . .

23.94 0.9559 0.18 Q . . . .

24.08 0.9581 0.18 Q . . . .

24.23 0.9592 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1446.5
10% 132.3
20% 26.5
30% 17.6
40% 8.8
50% 8.8
60% 8.8
70% 8.8
80% 8.8
90% 8.8
Item: 11
1656
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA C 2YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 3.48
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 7.39

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.53
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.06
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0005 0.10 Q . . . .

0.23 0.0015 0.10 Q . . . .

Item: 11
1657

0.36 0.0025 0.10 Q . . . .

0.48 0.0035 0.10 Q . . . .

0.60 0.0046 0.10 Q . . . .

0.73 0.0056 0.10 Q . . . .

0.85 0.0067 0.10 Q . . . .

0.97 0.0077 0.10 Q . . . .

1.10 0.0088 0.10 Q . . . .

1.22 0.0098 0.10 Q . . . .

1.34 0.0109 0.11 Q . . . .

1.47 0.0120 0.11 Q . . . .

1.59 0.0131 0.11 Q . . . .

1.71 0.0142 0.11 Q . . . .

1.84 0.0153 0.11 Q . . . .

1.96 0.0164 0.11 Q . . . .

2.08 0.0175 0.11 Q . . . .

2.21 0.0186 0.11 Q . . . .

2.33 0.0197 0.11 Q . . . .

2.45 0.0208 0.11 Q . . . .

2.57 0.0219 0.11 Q . . . .

2.70 0.0231 0.11 Q . . . .

2.82 0.0242 0.11 Q . . . .

2.94 0.0254 0.11 Q . . . .

3.07 0.0265 0.11 Q . . . .

3.19 0.0277 0.11 Q . . . .

3.31 0.0288 0.12 Q . . . .

3.44 0.0300 0.12 Q . . . .

3.56 0.0312 0.12 Q . . . .

3.68 0.0324 0.12 Q . . . .

3.81 0.0336 0.12 Q . . . .

3.93 0.0348 0.12 Q . . . .

4.05 0.0360 0.12 Q . . . .

4.18 0.0372 0.12 Q . . . .

4.30 0.0385 0.12 Q . . . .

4.42 0.0397 0.12 Q . . . .

4.55 0.0409 0.12 Q . . . .

4.67 0.0422 0.12 Q . . . .

4.79 0.0435 0.12 Q . . . .

4.92 0.0447 0.13 Q . . . .

5.04 0.0460 0.13 Q . . . .

5.16 0.0473 0.13 Q . . . .

5.28 0.0486 0.13 Q . . . .

5.41 0.0499 0.13 Q . . . .

5.53 0.0512 0.13 Q . . . .

5.65 0.0526 0.13 Q . . . .

5.78 0.0539 0.13 Q . . . .

5.90 0.0552 0.13 Q . . . .

6.02 0.0566 0.13 Q . . . .

6.15 0.0580 0.13 Q . . . .

6.27 0.0593 0.14 Q . . . .

6.39 0.0607 0.14 Q . . . .

Item: 11
1658

6.52 0.0621 0.14 Q . . . .

6.64 0.0635 0.14 Q . . . .

6.76 0.0650 0.14 Q . . . .

6.89 0.0664 0.14 Q . . . .

7.01 0.0678 0.14 Q . . . .

7.13 0.0693 0.14 Q . . . .

7.26 0.0708 0.15 Q . . . .

7.38 0.0722 0.15 Q . . . .

7.50 0.0737 0.15 Q . . . .

7.62 0.0752 0.15 Q . . . .

7.75 0.0768 0.15 Q . . . .

7.87 0.0783 0.15 Q . . . .

7.99 0.0799 0.15 Q . . . .

8.12 0.0814 0.15 Q . . . .

8.24 0.0830 0.16 Q . . . .

8.36 0.0846 0.16 Q . . . .

8.49 0.0862 0.16 Q . . . .

8.61 0.0879 0.16 Q . . . .

8.73 0.0895 0.16 Q . . . .

8.86 0.0912 0.16 Q . . . .

8.98 0.0929 0.17 Q . . . .

9.10 0.0946 0.17 Q . . . .

9.23 0.0963 0.17 Q . . . .

9.35 0.0980 0.17 Q . . . .

9.47 0.0998 0.17 Q . . . .

9.60 0.1015 0.18 Q . . . .

9.72 0.1033 0.18 Q . . . .

9.84 0.1052 0.18 Q . . . .

9.96 0.1070 0.18 Q . . . .

10.09 0.1089 0.18 Q . . . .

10.21 0.1108 0.19 Q . . . .

10.33 0.1127 0.19 Q . . . .

10.46 0.1146 0.19 Q . . . .

10.58 0.1166 0.19 Q . . . .

10.70 0.1186 0.20 Q . . . .

10.83 0.1206 0.20 Q . . . .

10.95 0.1227 0.20 Q . . . .

11.07 0.1248 0.21 Q . . . .

11.20 0.1269 0.21 Q . . . .

11.32 0.1290 0.21 Q . . . .

11.44 0.1312 0.22 Q . . . .

11.57 0.1335 0.22 Q . . . .

11.69 0.1357 0.22 Q . . . .

11.81 0.1380 0.23 Q . . . .

11.94 0.1404 0.23 Q . . . .

12.06 0.1428 0.24 Q . . . .

12.18 0.1455 0.29 .Q . . . .

12.30 0.1485 0.30 .Q . . . .

12.43 0.1515 0.30 .Q . . . .

12.55 0.1546 0.31 .Q . . . .

Item: 11
1659

12.67 0.1578 0.32 .Q . . . .

12.80 0.1611 0.32 .Q . . . .

12.92 0.1644 0.33 .Q . . . .

13.04 0.1677 0.33 .Q . . . .

13.17 0.1712 0.34 .Q . . . .

13.29 0.1747 0.35 .Q . . . .

13.41 0.1783 0.36 .Q . . . .

13.54 0.1821 0.37 .Q . . . .

13.66 0.1859 0.38 .Q . . . .

13.78 0.1898 0.39 .Q . . . .

13.91 0.1938 0.40 .Q . . . .

14.03 0.1980 0.41 .Q . . . .

14.15 0.2023 0.45 .Q . . . .

14.28 0.2069 0.46 .Q . . . .

14.40 0.2117 0.48 .Q . . . .

14.52 0.2167 0.49 .Q . . . .

14.65 0.2218 0.52 . Q . . . .

14.77 0.2272 0.54 . Q . . . .

14.89 0.2329 0.58 . Q . . . .

15.01 0.2389 0.60 . Q . . . .

15.14 0.2453 0.65 . Q . . . .

15.26 0.2521 0.68 . Q . . . .

15.38 0.2594 0.75 . Q . . . .

15.51 0.2668 0.71 . Q . . . .

15.63 0.2747 0.85 . Q . . . .

15.75 0.2839 0.96 . Q . . . .

15.88 0.2959 1.39 . Q . . . .

16.00 0.3126 1.90 . Q . . . .

16.12 0.3512 5.68 . . . Q . .

16.25 0.3859 1.14 . Q . . . .

16.37 0.3956 0.77 . Q . . . .

16.49 0.4032 0.72 . Q . . . .

16.62 0.4101 0.62 . Q . . . .

16.74 0.4161 0.56 . Q . . . .

16.86 0.4215 0.51 . Q . . . .

16.99 0.4265 0.47 .Q . . . .

17.11 0.4310 0.43 .Q . . . .

17.23 0.4352 0.40 .Q . . . .

17.35 0.4391 0.37 .Q . . . .

17.48 0.4428 0.36 .Q . . . .

17.60 0.4464 0.34 .Q . . . .

17.72 0.4497 0.32 .Q . . . .

17.85 0.4530 0.31 .Q . . . .

17.97 0.4561 0.30 .Q . . . .

18.09 0.4590 0.28 .Q . . . .

18.22 0.4616 0.23 Q . . . .

18.34 0.4639 0.22 Q . . . .

18.46 0.4661 0.21 Q . . . .

18.59 0.4683 0.21 Q . . . .

18.71 0.4704 0.20 Q . . . .

Item: 11
1660

18.83 0.4724 0.20 Q . . . .

18.96 0.4744 0.19 Q . . . .

19.08 0.4763 0.19 Q . . . .

19.20 0.4782 0.18 Q . . . .

19.33 0.4800 0.18 Q . . . .

19.45 0.4818 0.17 Q . . . .

19.57 0.4835 0.17 Q . . . .

19.69 0.4852 0.17 Q . . . .

19.82 0.4869 0.16 Q . . . .

19.94 0.4885 0.16 Q . . . .

20.06 0.4901 0.16 Q . . . .

20.19 0.4917 0.15 Q . . . .

20.31 0.4932 0.15 Q . . . .

20.43 0.4947 0.15 Q . . . .

20.56 0.4962 0.14 Q . . . .

20.68 0.4977 0.14 Q . . . .

20.80 0.4991 0.14 Q . . . .

20.93 0.5005 0.14 Q . . . .

21.05 0.5019 0.14 Q . . . .

21.17 0.5033 0.13 Q . . . .

21.30 0.5046 0.13 Q . . . .

21.42 0.5059 0.13 Q . . . .

21.54 0.5072 0.13 Q . . . .

21.67 0.5085 0.13 Q . . . .

21.79 0.5098 0.12 Q . . . .

21.91 0.5110 0.12 Q . . . .

22.04 0.5123 0.12 Q . . . .

22.16 0.5135 0.12 Q . . . .

22.28 0.5147 0.12 Q . . . .

22.40 0.5159 0.12 Q . . . .

22.53 0.5171 0.11 Q . . . .

22.65 0.5182 0.11 Q . . . .

22.77 0.5194 0.11 Q . . . .

22.90 0.5205 0.11 Q . . . .

23.02 0.5216 0.11 Q . . . .

23.14 0.5228 0.11 Q . . . .

23.27 0.5239 0.11 Q . . . .

23.39 0.5249 0.11 Q . . . .

23.51 0.5260 0.11 Q . . . .

23.64 0.5271 0.10 Q . . . .

23.76 0.5281 0.10 Q . . . .

23.88 0.5292 0.10 Q . . . .

24.01 0.5302 0.10 Q . . . .

24.13 0.5307 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Item: 11
1661
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1441.0
10% 110.8
20% 29.6
30% 14.8
40% 7.4
50% 7.4
60% 7.4
70% 7.4
80% 7.4
90% 7.4
Item: 11
1662
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA D 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 4.02
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 18.01

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.61
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.07
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.09 0.0000 0.00 Q . . . .

0.39 0.0014 0.12 Q . . . .

Item: 11
1663

0.69 0.0043 0.12 Q . . . .

0.99 0.0073 0.12 Q . . . .

1.29 0.0103 0.12 Q . . . .

1.59 0.0133 0.12 Q . . . .

1.89 0.0163 0.12 Q . . . .

2.19 0.0194 0.13 Q . . . .

2.49 0.0225 0.13 Q . . . .

2.79 0.0257 0.13 Q . . . .

3.09 0.0289 0.13 Q . . . .

3.39 0.0322 0.13 Q . . . .

3.69 0.0355 0.13 Q . . . .

3.99 0.0389 0.14 Q . . . .

4.29 0.0423 0.14 Q . . . .

4.59 0.0458 0.14 Q . . . .

4.89 0.0493 0.14 Q . . . .

5.19 0.0529 0.15 Q . . . .

5.49 0.0565 0.15 Q . . . .

5.79 0.0603 0.15 Q . . . .

6.09 0.0640 0.15 Q . . . .

6.39 0.0679 0.16 Q . . . .

6.69 0.0718 0.16 Q . . . .

6.99 0.0758 0.16 Q . . . .

7.30 0.0799 0.17 Q . . . .

7.60 0.0841 0.17 Q . . . .

7.90 0.0883 0.17 Q . . . .

8.20 0.0927 0.18 Q . . . .

8.50 0.0972 0.18 Q . . . .

8.80 0.1017 0.19 Q . . . .

9.10 0.1064 0.19 Q . . . .

9.40 0.1112 0.20 Q . . . .

9.70 0.1162 0.20 Q . . . .

10.00 0.1213 0.21 Q . . . .

10.30 0.1265 0.22 Q . . . .

10.60 0.1319 0.22 Q . . . .

10.90 0.1375 0.23 Q . . . .

11.20 0.1433 0.24 Q . . . .

11.50 0.1493 0.25 Q . . . .

11.80 0.1556 0.26 .Q . . . .

12.10 0.1621 0.27 .Q . . . .

12.40 0.1697 0.34 .Q . . . .

12.70 0.1784 0.36 .Q . . . .

13.00 0.1874 0.37 .Q . . . .

13.30 0.1970 0.40 .Q . . . .

13.60 0.2071 0.41 .Q . . . .

13.90 0.2178 0.45 .Q . . . .

14.20 0.2294 0.48 .Q . . . .

14.50 0.2421 0.55 . Q . . . .

14.80 0.2563 0.59 . Q . . . .

15.10 0.2722 0.70 . Q . . . .

15.40 0.2904 0.77 . Q . . . .

Item: 11
1664

15.70 0.3115 0.93 . Q . . . .

16.00 0.3391 1.29 . Q . . . .

16.30 0.4035 3.90 . . Q . . .

16.60 0.4623 0.84 . Q . . . .

16.90 0.4806 0.64 . Q . . . .

17.20 0.4950 0.52 . Q . . . .

17.50 0.5068 0.43 .Q . . . .

17.80 0.5169 0.38 .Q . . . .

18.10 0.5260 0.35 .Q . . . .

18.40 0.5336 0.26 .Q . . . .

18.70 0.5399 0.24 Q . . . .

19.00 0.5457 0.23 Q . . . .

19.30 0.5511 0.21 Q . . . .

19.60 0.5562 0.20 Q . . . .

19.90 0.5610 0.19 Q . . . .

20.20 0.5656 0.18 Q . . . .

20.50 0.5700 0.17 Q . . . .

20.80 0.5742 0.16 Q . . . .

21.10 0.5782 0.16 Q . . . .

21.40 0.5820 0.15 Q . . . .

21.70 0.5857 0.15 Q . . . .

22.00 0.5893 0.14 Q . . . .

22.30 0.5928 0.14 Q . . . .

22.60 0.5962 0.13 Q . . . .

22.90 0.5994 0.13 Q . . . .

23.20 0.6026 0.13 Q . . . .

23.50 0.6057 0.12 Q . . . .

23.80 0.6087 0.12 Q . . . .

24.10 0.6116 0.12 Q . . . .

24.40 0.6131 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.8
10% 270.1
20% 72.0
30% 36.0
40% 18.0
50% 18.0
60% 18.0
70% 18.0
80% 18.0
90% 18.0
Item: 11
1665
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA A 100 YEAR UNIT HYDROGRAPH

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.61
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.07
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0005 0.11 Q . . . .

0.21 0.0015 0.11 Q . . . .

Item: 11
1666

0.32 0.0025 0.12 Q . . . .

0.43 0.0035 0.12 Q . . . .

0.53 0.0046 0.12 Q . . . .

0.64 0.0056 0.12 Q . . . .

0.75 0.0066 0.12 Q . . . .

0.85 0.0076 0.12 Q . . . .

0.96 0.0087 0.12 Q . . . .

1.07 0.0097 0.12 Q . . . .

1.17 0.0108 0.12 Q . . . .

1.28 0.0118 0.12 Q . . . .

1.39 0.0129 0.12 Q . . . .

1.49 0.0139 0.12 Q . . . .

1.60 0.0150 0.12 Q . . . .

1.71 0.0161 0.12 Q . . . .

1.81 0.0172 0.12 Q . . . .

1.92 0.0182 0.12 Q . . . .

2.03 0.0193 0.12 Q . . . .

2.13 0.0204 0.12 Q . . . .

2.24 0.0215 0.12 Q . . . .

2.35 0.0226 0.13 Q . . . .

2.45 0.0237 0.13 Q . . . .

2.56 0.0248 0.13 Q . . . .

2.67 0.0260 0.13 Q . . . .

2.77 0.0271 0.13 Q . . . .

2.88 0.0282 0.13 Q . . . .

2.99 0.0294 0.13 Q . . . .

3.09 0.0305 0.13 Q . . . .

3.20 0.0316 0.13 Q . . . .

3.31 0.0328 0.13 Q . . . .

3.41 0.0340 0.13 Q . . . .

3.52 0.0351 0.13 Q . . . .

3.63 0.0363 0.13 Q . . . .

3.73 0.0375 0.13 Q . . . .

3.84 0.0387 0.13 Q . . . .

3.95 0.0399 0.14 Q . . . .

4.05 0.0411 0.14 Q . . . .

4.16 0.0423 0.14 Q . . . .

4.27 0.0435 0.14 Q . . . .

4.37 0.0447 0.14 Q . . . .

4.48 0.0459 0.14 Q . . . .

4.59 0.0471 0.14 Q . . . .

4.69 0.0484 0.14 Q . . . .

4.80 0.0496 0.14 Q . . . .

4.91 0.0509 0.14 Q . . . .

5.01 0.0522 0.14 Q . . . .

5.12 0.0534 0.14 Q . . . .

5.23 0.0547 0.15 Q . . . .

5.33 0.0560 0.15 Q . . . .

5.44 0.0573 0.15 Q . . . .

5.55 0.0586 0.15 Q . . . .

Item: 11
1667

5.65 0.0599 0.15 Q . . . .

5.76 0.0612 0.15 Q . . . .

5.87 0.0625 0.15 Q . . . .

5.97 0.0639 0.15 Q . . . .

6.08 0.0652 0.15 Q . . . .

6.19 0.0666 0.15 Q . . . .

6.29 0.0679 0.16 Q . . . .

6.40 0.0693 0.16 Q . . . .

6.51 0.0707 0.16 Q . . . .

6.61 0.0721 0.16 Q . . . .

6.72 0.0735 0.16 Q . . . .

6.83 0.0749 0.16 Q . . . .

6.93 0.0763 0.16 Q . . . .

7.04 0.0777 0.16 Q . . . .

7.15 0.0792 0.16 Q . . . .

7.25 0.0806 0.17 Q . . . .

7.36 0.0821 0.17 Q . . . .

7.47 0.0836 0.17 Q . . . .

7.57 0.0851 0.17 Q . . . .

7.68 0.0866 0.17 Q . . . .

7.79 0.0881 0.17 Q . . . .

7.89 0.0896 0.17 Q . . . .

8.00 0.0911 0.18 Q . . . .

8.11 0.0927 0.18 Q . . . .

8.21 0.0942 0.18 Q . . . .

8.32 0.0958 0.18 Q . . . .

8.43 0.0974 0.18 Q . . . .

8.53 0.0990 0.18 Q . . . .

8.64 0.1006 0.18 Q . . . .

8.75 0.1023 0.19 Q . . . .

8.85 0.1039 0.19 Q . . . .

8.96 0.1056 0.19 Q . . . .

9.07 0.1072 0.19 Q . . . .

9.17 0.1089 0.19 Q . . . .

9.28 0.1106 0.20 Q . . . .

9.39 0.1124 0.20 Q . . . .

9.49 0.1141 0.20 Q . . . .

9.60 0.1159 0.20 Q . . . .

9.71 0.1176 0.20 Q . . . .

9.81 0.1194 0.20 Q . . . .

9.92 0.1213 0.21 Q . . . .

10.03 0.1231 0.21 Q . . . .

10.13 0.1250 0.21 Q . . . .

10.24 0.1268 0.21 Q . . . .

10.35 0.1287 0.22 Q . . . .

10.45 0.1307 0.22 Q . . . .

10.56 0.1326 0.22 Q . . . .

10.67 0.1346 0.22 Q . . . .

10.77 0.1366 0.23 Q . . . .

10.88 0.1386 0.23 Q . . . .

Item: 11
1668

10.99 0.1406 0.23 Q . . . .

11.09 0.1427 0.24 Q . . . .

11.20 0.1448 0.24 Q . . . .

11.31 0.1469 0.24 Q . . . .

11.41 0.1491 0.25 Q . . . .

11.52 0.1513 0.25 Q . . . .

11.63 0.1535 0.25 .Q . . . .

11.73 0.1558 0.26 .Q . . . .

11.84 0.1581 0.26 .Q . . . .

11.95 0.1604 0.27 .Q . . . .

12.05 0.1628 0.29 .Q . . . .

12.16 0.1656 0.34 .Q . . . .

12.27 0.1687 0.35 .Q . . . .

12.37 0.1718 0.35 .Q . . . .

12.48 0.1750 0.36 .Q . . . .

12.59 0.1782 0.37 .Q . . . .

12.69 0.1814 0.37 .Q . . . .

12.80 0.1847 0.38 .Q . . . .

12.91 0.1881 0.39 .Q . . . .

13.01 0.1915 0.39 .Q . . . .

13.12 0.1950 0.40 .Q . . . .

13.23 0.1986 0.41 .Q . . . .

13.33 0.2022 0.42 .Q . . . .

13.44 0.2060 0.42 .Q . . . .

13.55 0.2097 0.44 .Q . . . .

13.65 0.2136 0.44 .Q . . . .

13.76 0.2176 0.46 .Q . . . .

13.87 0.2217 0.47 .Q . . . .

13.97 0.2258 0.48 .Q . . . .

14.08 0.2301 0.49 .Q . . . .

14.19 0.2345 0.51 . Q . . . .

14.29 0.2391 0.52 . Q . . . .

14.40 0.2438 0.55 . Q . . . .

14.51 0.2487 0.56 . Q . . . .

14.61 0.2538 0.59 . Q . . . .

14.72 0.2590 0.60 . Q . . . .

14.83 0.2645 0.64 . Q . . . .

14.93 0.2702 0.66 . Q . . . .

15.04 0.2762 0.71 . Q . . . .

15.15 0.2826 0.73 . Q . . . .

15.25 0.2893 0.80 . Q . . . .

15.36 0.2965 0.84 . Q . . . .

15.47 0.3039 0.83 . Q . . . .

15.57 0.3114 0.89 . Q . . . .

15.68 0.3200 1.07 . Q . . . .

15.79 0.3301 1.20 . Q . . . .

15.89 0.3429 1.71 . Q . . . .

16.00 0.3607 2.34 . Q. . . .

16.11 0.4021 7.04 . . . Q . .

16.21 0.4393 1.40 . Q . . . .

Item: 11
1669

16.32 0.4497 0.97 . Q . . . .

16.43 0.4577 0.84 . Q . . . .

16.53 0.4648 0.76 . Q . . . .

16.64 0.4712 0.68 . Q . . . .

16.75 0.4769 0.62 . Q . . . .

16.85 0.4821 0.57 . Q . . . .

16.96 0.4870 0.53 . Q . . . .

17.07 0.4916 0.50 . Q . . . .

17.17 0.4959 0.47 .Q . . . .

17.28 0.5000 0.45 .Q . . . .

17.39 0.5039 0.43 .Q . . . .

17.49 0.5076 0.41 .Q . . . .

17.60 0.5111 0.40 .Q . . . .

17.71 0.5146 0.38 .Q . . . .

17.81 0.5179 0.37 .Q . . . .

17.92 0.5211 0.36 .Q . . . .

18.03 0.5242 0.35 .Q . . . .

18.13 0.5269 0.27 .Q . . . .

18.24 0.5292 0.26 .Q . . . .

18.35 0.5315 0.25 .Q . . . .

18.45 0.5337 0.24 Q . . . .

18.56 0.5358 0.24 Q . . . .

18.67 0.5379 0.23 Q . . . .

18.77 0.5399 0.23 Q . . . .

18.88 0.5419 0.22 Q . . . .

18.99 0.5438 0.22 Q . . . .

19.09 0.5457 0.21 Q . . . .

19.20 0.5475 0.21 Q . . . .

19.31 0.5493 0.20 Q . . . .

19.41 0.5511 0.20 Q . . . .

19.52 0.5528 0.19 Q . . . .

19.63 0.5545 0.19 Q . . . .

19.73 0.5562 0.19 Q . . . .

19.84 0.5578 0.18 Q . . . .

19.95 0.5594 0.18 Q . . . .

20.05 0.5610 0.18 Q . . . .

20.16 0.5625 0.17 Q . . . .

20.27 0.5640 0.17 Q . . . .

20.37 0.5655 0.17 Q . . . .

20.48 0.5670 0.17 Q . . . .

20.59 0.5685 0.16 Q . . . .

20.69 0.5699 0.16 Q . . . .

20.80 0.5713 0.16 Q . . . .

20.91 0.5727 0.16 Q . . . .

21.01 0.5741 0.15 Q . . . .

21.12 0.5754 0.15 Q . . . .

21.23 0.5768 0.15 Q . . . .

21.33 0.5781 0.15 Q . . . .

21.44 0.5794 0.15 Q . . . .

21.55 0.5807 0.14 Q . . . .

Item: 11
1670

21.65 0.5819 0.14 Q . . . .

21.76 0.5832 0.14 Q . . . .

21.87 0.5844 0.14 Q . . . .

21.97 0.5857 0.14 Q . . . .

22.08 0.5869 0.14 Q . . . .

22.19 0.5881 0.14 Q . . . .

22.29 0.5893 0.13 Q . . . .

22.40 0.5904 0.13 Q . . . .

22.51 0.5916 0.13 Q . . . .

22.61 0.5927 0.13 Q . . . .

22.72 0.5939 0.13 Q . . . .

22.83 0.5950 0.13 Q . . . .

22.93 0.5961 0.13 Q . . . .

23.04 0.5972 0.12 Q . . . .

23.15 0.5983 0.12 Q . . . .

23.25 0.5994 0.12 Q . . . .

23.36 0.6005 0.12 Q . . . .

23.47 0.6015 0.12 Q . . . .

23.57 0.6026 0.12 Q . . . .

23.68 0.6036 0.12 Q . . . .

23.79 0.6047 0.12 Q . . . .

23.89 0.6057 0.12 Q . . . .

24.00 0.6067 0.11 Q . . . .

24.11 0.6072 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.0
10% 96.0
20% 19.2
30% 12.8
40% 6.4
50% 6.4
60% 6.4
70% 6.4
80% 6.4
90% 6.4
Item: 11
1671
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA B 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 6.28
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 8.82

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 2.63
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.31
**************************************************************************** TIME VOLUME Q 0. 7.5 15.0 22.5 30.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.12 0.0030 0.49 Q . . . .

0.27 0.0090 0.50 Q . . . .

Item: 11
1672

0.42 0.0151 0.50 Q . . . .

0.57 0.0212 0.50 Q . . . .

0.71 0.0273 0.50 Q . . . .

0.86 0.0334 0.51 Q . . . .

1.01 0.0396 0.51 Q . . . .

1.15 0.0459 0.52 Q . . . .

1.30 0.0521 0.52 Q . . . .

1.45 0.0585 0.52 Q . . . .

1.59 0.0648 0.52 Q . . . .

1.74 0.0712 0.53 Q . . . .

1.89 0.0776 0.53 Q . . . .

2.04 0.0841 0.54 Q . . . .

2.18 0.0906 0.54 Q . . . .

2.33 0.0972 0.54 Q . . . .

2.48 0.1038 0.54 Q . . . .

2.62 0.1104 0.55 Q . . . .

2.77 0.1171 0.55 Q . . . .

2.92 0.1239 0.56 Q . . . .

3.06 0.1307 0.56 Q . . . .

3.21 0.1375 0.57 Q . . . .

3.36 0.1444 0.57 Q . . . .

3.51 0.1513 0.57 Q . . . .

3.65 0.1583 0.58 Q . . . .

3.80 0.1654 0.58 Q . . . .

3.95 0.1724 0.59 Q . . . .

4.09 0.1796 0.59 Q . . . .

4.24 0.1868 0.59 Q . . . .

4.39 0.1940 0.60 Q . . . .

4.53 0.2014 0.60 Q . . . .

4.68 0.2087 0.61 Q . . . .

4.83 0.2162 0.61 Q . . . .

4.98 0.2237 0.62 Q . . . .

5.12 0.2312 0.62 Q . . . .

5.27 0.2388 0.63 Q . . . .

5.42 0.2465 0.63 Q . . . .

5.56 0.2543 0.64 Q . . . .

5.71 0.2621 0.65 Q . . . .

5.86 0.2700 0.65 Q . . . .

6.00 0.2779 0.66 Q . . . .

6.15 0.2860 0.67 Q . . . .

6.30 0.2941 0.67 Q . . . .

6.45 0.3023 0.68 Q . . . .

6.59 0.3105 0.68 Q . . . .

6.74 0.3189 0.69 Q . . . .

6.89 0.3273 0.70 Q . . . .

7.03 0.3358 0.71 Q . . . .

7.18 0.3444 0.71 Q . . . .

7.33 0.3531 0.72 Q . . . .

7.47 0.3619 0.73 Q . . . .

7.62 0.3707 0.74 Q . . . .

Item: 11
1673

7.77 0.3797 0.74 Q . . . .

7.92 0.3888 0.75 .Q . . . .

8.06 0.3979 0.76 .Q . . . .

8.21 0.4072 0.77 .Q . . . .

8.36 0.4166 0.78 .Q . . . .

8.50 0.4261 0.79 .Q . . . .

8.65 0.4357 0.79 .Q . . . .

8.80 0.4455 0.81 .Q . . . .

8.94 0.4553 0.81 .Q . . . .

9.09 0.4653 0.83 .Q . . . .

9.24 0.4754 0.84 .Q . . . .

9.39 0.4857 0.85 .Q . . . .

9.53 0.4961 0.86 .Q . . . .

9.68 0.5066 0.88 .Q . . . .

9.83 0.5173 0.88 .Q . . . .

9.97 0.5281 0.90 .Q . . . .

10.12 0.5391 0.91 .Q . . . .

10.27 0.5503 0.93 .Q . . . .

10.41 0.5617 0.94 .Q . . . .

10.56 0.5732 0.96 .Q . . . .

10.71 0.5850 0.97 .Q . . . .

10.85 0.5969 0.99 .Q . . . .

11.00 0.6091 1.01 .Q . . . .

11.15 0.6215 1.03 .Q . . . .

11.30 0.6341 1.04 .Q . . . .

11.44 0.6469 1.07 .Q . . . .

11.59 0.6600 1.09 .Q . . . .

11.74 0.6734 1.12 .Q . . . .

11.88 0.6871 1.13 .Q . . . .

12.03 0.7010 1.17 .Q . . . .

12.18 0.7168 1.43 .Q . . . .

12.32 0.7348 1.53 . Q . . . .

12.47 0.7534 1.55 . Q . . . .

12.62 0.7725 1.59 . Q . . . .

12.77 0.7920 1.62 . Q . . . .

12.91 0.8120 1.67 . Q . . . .

13.06 0.8325 1.70 . Q . . . .

13.21 0.8535 1.76 . Q . . . .

13.35 0.8750 1.79 . Q . . . .

13.50 0.8972 1.86 . Q . . . .

13.65 0.9201 1.90 . Q . . . .

13.80 0.9437 1.99 . Q . . . .

13.94 0.9681 2.03 . Q . . . .

14.09 0.9935 2.14 . Q . . . .

14.24 1.0198 2.20 . Q . . . .

14.38 1.0474 2.33 . Q . . . .

14.53 1.0762 2.41 . Q . . . .

14.68 1.1065 2.58 . Q . . . .

14.82 1.1385 2.68 . Q . . . .

14.97 1.1725 2.92 . Q . . . .

Item: 11
1674

15.12 1.2088 3.06 . Q . . . .

15.27 1.2482 3.42 . Q . . . .

15.41 1.2912 3.66 . Q . . . .

15.56 1.3367 3.83 . Q . . . .

15.71 1.3861 4.31 . Q . . . .

15.85 1.4496 6.14 . Q . . . .

16.00 1.5378 8.38 . .Q . . .

16.15 1.7422 25.28 . . . . Q .

16.29 1.9262 5.01 . Q . . . .

16.44 1.9783 3.56 . Q . . . .

16.59 2.0195 3.23 . Q . . . .

16.73 2.0561 2.79 . Q . . . .

16.88 2.0881 2.49 . Q . . . .

17.03 2.1170 2.27 . Q . . . .

17.18 2.1434 2.08 . Q . . . .

17.32 2.1679 1.94 . Q . . . .

17.47 2.1908 1.83 . Q . . . .

17.62 2.2124 1.73 . Q . . . .

17.76 2.2328 1.64 . Q . . . .

17.91 2.2524 1.57 . Q . . . .

18.06 2.2711 1.51 . Q . . . .

18.20 2.2872 1.15 .Q . . . .

18.35 2.3009 1.10 .Q . . . .

18.50 2.3140 1.06 .Q . . . .

18.65 2.3266 1.02 .Q . . . .

18.79 2.3387 0.98 .Q . . . .

18.94 2.3505 0.95 .Q . . . .

19.09 2.3618 0.92 .Q . . . .

19.23 2.3729 0.89 .Q . . . .

19.38 2.3836 0.87 .Q . . . .

19.53 2.3939 0.84 .Q . . . .

19.67 2.4041 0.82 .Q . . . .

19.82 2.4139 0.80 .Q . . . .

19.97 2.4235 0.78 .Q . . . .

20.12 2.4329 0.76 .Q . . . .

20.26 2.4421 0.75 Q . . . .

20.41 2.4511 0.73 Q . . . .

20.56 2.4598 0.71 Q . . . .

20.70 2.4684 0.70 Q . . . .

20.85 2.4769 0.69 Q . . . .

21.00 2.4851 0.67 Q . . . .

21.14 2.4932 0.66 Q . . . .

21.29 2.5012 0.65 Q . . . .

21.44 2.5090 0.64 Q . . . .

21.59 2.5167 0.63 Q . . . .

21.73 2.5243 0.62 Q . . . .

21.88 2.5317 0.61 Q . . . .

22.03 2.5390 0.60 Q . . . .

22.17 2.5462 0.59 Q . . . .

22.32 2.5533 0.58 Q . . . .

Item: 11
1675

22.47 2.5603 0.57 Q . . . .

22.61 2.5672 0.56 Q . . . .

22.76 2.5740 0.55 Q . . . .

22.91 2.5807 0.55 Q . . . .

23.06 2.5873 0.54 Q . . . .

23.20 2.5938 0.53 Q . . . .

23.35 2.6002 0.53 Q . . . .

23.50 2.6066 0.52 Q . . . .

23.64 2.6128 0.51 Q . . . .

23.79 2.6190 0.51 Q . . . .

23.94 2.6252 0.50 Q . . . .

24.08 2.6312 0.50 Q . . . .

24.23 2.6342 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1446.5
10% 132.3
20% 26.5
30% 17.6
40% 8.8
50% 8.8
60% 8.8
70% 8.8
80% 8.8
90% 8.8
Item: 11
1676
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA C 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 3.48
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 7.39

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 1.46
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.18
**************************************************************************** TIME VOLUME Q 0. 5.0 10.0 15.0 20.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0013 0.27 Q . . . .

0.23 0.0041 0.27 Q . . . .

Item: 11
1677

0.36 0.0069 0.28 Q . . . .

0.48 0.0097 0.28 Q . . . .

0.60 0.0125 0.28 Q . . . .

0.73 0.0154 0.28 Q . . . .

0.85 0.0182 0.28 Q . . . .

0.97 0.0211 0.28 Q . . . .

1.10 0.0240 0.29 Q . . . .

1.22 0.0269 0.29 Q . . . .

1.34 0.0298 0.29 Q . . . .

1.47 0.0328 0.29 Q . . . .

1.59 0.0357 0.29 Q . . . .

1.71 0.0387 0.29 Q . . . .

1.84 0.0417 0.29 Q . . . .

1.96 0.0447 0.30 Q . . . .

2.08 0.0477 0.30 Q . . . .

2.21 0.0507 0.30 Q . . . .

2.33 0.0538 0.30 Q . . . .

2.45 0.0568 0.30 Q . . . .

2.57 0.0599 0.30 Q . . . .

2.70 0.0630 0.31 Q . . . .

2.82 0.0661 0.31 Q . . . .

2.94 0.0693 0.31 Q . . . .

3.07 0.0724 0.31 Q . . . .

3.19 0.0756 0.31 Q . . . .

3.31 0.0788 0.32 Q . . . .

3.44 0.0820 0.32 Q . . . .

3.56 0.0853 0.32 Q . . . .

3.68 0.0885 0.32 Q . . . .

3.81 0.0918 0.32 Q . . . .

3.93 0.0951 0.32 Q . . . .

4.05 0.0984 0.33 Q . . . .

4.18 0.1017 0.33 Q . . . .

4.30 0.1051 0.33 Q . . . .

4.42 0.1085 0.33 Q . . . .

4.55 0.1119 0.34 Q . . . .

4.67 0.1153 0.34 Q . . . .

4.79 0.1188 0.34 Q . . . .

4.92 0.1222 0.34 Q . . . .

5.04 0.1257 0.35 Q . . . .

5.16 0.1293 0.35 Q . . . .

5.28 0.1328 0.35 Q . . . .

5.41 0.1364 0.35 Q . . . .

5.53 0.1400 0.36 Q . . . .

5.65 0.1436 0.36 Q . . . .

5.78 0.1473 0.36 Q . . . .

5.90 0.1509 0.36 Q . . . .

6.02 0.1546 0.37 Q . . . .

6.15 0.1584 0.37 Q . . . .

6.27 0.1621 0.37 Q . . . .

6.39 0.1659 0.37 Q . . . .

Item: 11
1678

6.52 0.1698 0.38 Q . . . .

6.64 0.1736 0.38 Q . . . .

6.76 0.1775 0.38 Q . . . .

6.89 0.1814 0.39 Q . . . .

7.01 0.1854 0.39 Q . . . .

7.13 0.1894 0.39 Q . . . .

7.26 0.1934 0.40 Q . . . .

7.38 0.1974 0.40 Q . . . .

7.50 0.2015 0.40 Q . . . .

7.62 0.2057 0.41 Q . . . .

7.75 0.2098 0.41 Q . . . .

7.87 0.2140 0.41 Q . . . .

7.99 0.2183 0.42 Q . . . .

8.12 0.2226 0.42 Q . . . .

8.24 0.2269 0.43 Q . . . .

8.36 0.2313 0.43 Q . . . .

8.49 0.2357 0.44 Q . . . .

8.61 0.2401 0.44 Q . . . .

8.73 0.2447 0.45 Q . . . .

8.86 0.2492 0.45 Q . . . .

8.98 0.2538 0.46 Q . . . .

9.10 0.2585 0.46 Q . . . .

9.23 0.2632 0.47 Q . . . .

9.35 0.2679 0.47 Q . . . .

9.47 0.2727 0.48 Q . . . .

9.60 0.2776 0.48 Q . . . .

9.72 0.2825 0.49 Q . . . .

9.84 0.2875 0.49 Q . . . .

9.96 0.2926 0.50 .Q . . . .

10.09 0.2977 0.50 .Q . . . .

10.21 0.3029 0.51 .Q . . . .

10.33 0.3081 0.52 .Q . . . .

10.46 0.3134 0.53 .Q . . . .

10.58 0.3188 0.53 .Q . . . .

10.70 0.3243 0.54 .Q . . . .

10.83 0.3298 0.55 .Q . . . .

10.95 0.3355 0.56 .Q . . . .

11.07 0.3412 0.56 .Q . . . .

11.20 0.3470 0.58 .Q . . . .

11.32 0.3529 0.58 .Q . . . .

11.44 0.3589 0.60 .Q . . . .

11.57 0.3650 0.60 .Q . . . .

11.69 0.3712 0.62 .Q . . . .

11.81 0.3775 0.62 .Q . . . .

11.94 0.3839 0.64 .Q . . . .

12.06 0.3904 0.65 .Q . . . .

12.18 0.3979 0.83 .Q . . . .

12.30 0.4065 0.84 .Q . . . .

12.43 0.4151 0.86 .Q . . . .

12.55 0.4239 0.87 .Q . . . .

Item: 11
1679

12.67 0.4329 0.89 .Q . . . .

12.80 0.4421 0.90 .Q . . . .

12.92 0.4514 0.93 .Q . . . .

13.04 0.4609 0.94 .Q . . . .

13.17 0.4707 0.97 .Q . . . .

13.29 0.4806 0.99 .Q . . . .

13.41 0.4908 1.02 . Q . . . .

13.54 0.5012 1.03 . Q . . . .

13.66 0.5120 1.07 . Q . . . .

13.78 0.5230 1.09 . Q . . . .

13.91 0.5343 1.13 . Q . . . .

14.03 0.5459 1.16 . Q . . . .

14.15 0.5580 1.22 . Q . . . .

14.28 0.5705 1.24 . Q . . . .

14.40 0.5835 1.31 . Q . . . .

14.52 0.5970 1.34 . Q . . . .

14.65 0.6111 1.42 . Q . . . .

14.77 0.6257 1.47 . Q . . . .

14.89 0.6412 1.57 . Q . . . .

15.01 0.6575 1.63 . Q . . . .

15.14 0.6748 1.78 . Q . . . .

15.26 0.6933 1.86 . Q . . . .

15.38 0.7133 2.05 . Q . . . .

15.51 0.7337 1.96 . Q . . . .

15.63 0.7556 2.35 . Q . . . .

15.75 0.7811 2.65 . Q . . . .

15.88 0.8138 3.77 . Q . . . .

16.00 0.8592 5.15 . Q . . .

16.12 0.9645 15.54 . . . .Q .

16.25 1.0593 3.09 . Q . . . .

16.37 1.0859 2.13 . Q . . . .

16.49 1.1068 1.96 . Q . . . .

16.62 1.1254 1.70 . Q . . . .

16.74 1.1417 1.52 . Q . . . .

16.86 1.1565 1.38 . Q . . . .

16.99 1.1700 1.27 . Q . . . .

17.11 1.1825 1.18 . Q . . . .

17.23 1.1942 1.11 . Q . . . .

17.35 1.2052 1.05 . Q . . . .

17.48 1.2157 1.00 . Q . . . .

17.60 1.2256 0.96 .Q . . . .

17.72 1.2351 0.92 .Q . . . .

17.85 1.2443 0.88 .Q . . . .

17.97 1.2531 0.85 .Q . . . .

18.09 1.2614 0.77 .Q . . . .

18.22 1.2685 0.63 .Q . . . .

18.34 1.2748 0.61 .Q . . . .

18.46 1.2809 0.59 .Q . . . .

18.59 1.2868 0.57 .Q . . . .

18.71 1.2925 0.55 .Q . . . .

Item: 11
1680

18.83 1.2981 0.54 .Q . . . .

18.96 1.3035 0.52 .Q . . . .

19.08 1.3087 0.51 .Q . . . .

19.20 1.3139 0.50 Q . . . .

19.33 1.3188 0.48 Q . . . .

19.45 1.3237 0.47 Q . . . .

19.57 1.3285 0.46 Q . . . .

19.69 1.3331 0.45 Q . . . .

19.82 1.3377 0.44 Q . . . .

19.94 1.3421 0.43 Q . . . .

20.06 1.3465 0.43 Q . . . .

20.19 1.3508 0.42 Q . . . .

20.31 1.3550 0.41 Q . . . .

20.43 1.3591 0.40 Q . . . .

20.56 1.3632 0.40 Q . . . .

20.68 1.3672 0.39 Q . . . .

20.80 1.3711 0.38 Q . . . .

20.93 1.3750 0.38 Q . . . .

21.05 1.3788 0.37 Q . . . .

21.17 1.3825 0.36 Q . . . .

21.30 1.3862 0.36 Q . . . .

21.42 1.3898 0.35 Q . . . .

21.54 1.3934 0.35 Q . . . .

21.67 1.3969 0.34 Q . . . .

21.79 1.4004 0.34 Q . . . .

21.91 1.4038 0.33 Q . . . .

22.04 1.4072 0.33 Q . . . .

22.16 1.4105 0.33 Q . . . .

22.28 1.4138 0.32 Q . . . .

22.40 1.4171 0.32 Q . . . .

22.53 1.4203 0.31 Q . . . .

22.65 1.4234 0.31 Q . . . .

22.77 1.4266 0.31 Q . . . .

22.90 1.4297 0.30 Q . . . .

23.02 1.4328 0.30 Q . . . .

23.14 1.4358 0.30 Q . . . .

23.27 1.4388 0.29 Q . . . .

23.39 1.4418 0.29 Q . . . .

23.51 1.4447 0.29 Q . . . .

23.64 1.4476 0.28 Q . . . .

23.76 1.4505 0.28 Q . . . .

23.88 1.4533 0.28 Q . . . .

24.01 1.4561 0.28 Q . . . .

24.13 1.4576 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Item: 11
1681
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1441.0
10% 110.8
20% 22.2
30% 14.8
40% 7.4
50% 7.4
60% 7.4
70% 7.4
80% 7.4
90% 7.4
Item: 11
1682
____________________________________________________________________________ ****************************************************************************

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA D 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 4.02
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 18.01

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 1.68
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.20
**************************************************************************** TIME VOLUME Q 0. 5.0 10.0 15.0 20.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.09 0.0000 0.00 Q . . . .

0.39 0.0039 0.32 Q . . . .

Item: 11
1683

0.69 0.0119 0.32 Q . . . .

0.99 0.0199 0.32 Q . . . .

1.29 0.0280 0.33 Q . . . .

1.59 0.0363 0.33 Q . . . .

1.89 0.0446 0.34 Q . . . .

2.19 0.0530 0.34 Q . . . .

2.49 0.0616 0.35 Q . . . .

2.79 0.0703 0.35 Q . . . .

3.09 0.0791 0.36 Q . . . .

3.39 0.0880 0.36 Q . . . .

3.69 0.0971 0.37 Q . . . .

3.99 0.1063 0.37 Q . . . .

4.29 0.1156 0.38 Q . . . .

4.59 0.1251 0.38 Q . . . .

4.89 0.1347 0.39 Q . . . .

5.19 0.1445 0.40 Q . . . .

5.49 0.1545 0.41 Q . . . .

5.79 0.1647 0.41 Q . . . .

6.09 0.1750 0.42 Q . . . .

6.39 0.1855 0.43 Q . . . .

6.69 0.1962 0.44 Q . . . .

6.99 0.2072 0.44 Q . . . .

7.30 0.2184 0.46 Q . . . .

7.60 0.2298 0.46 Q . . . .

7.90 0.2414 0.48 Q . . . .

8.20 0.2533 0.48 Q . . . .

8.50 0.2656 0.50 Q . . . .

8.80 0.2781 0.51 .Q . . . .

9.10 0.2909 0.53 .Q . . . .

9.40 0.3041 0.54 .Q . . . .

9.70 0.3176 0.56 .Q . . . .

10.00 0.3315 0.57 .Q . . . .

10.30 0.3459 0.59 .Q . . . .

10.60 0.3607 0.60 .Q . . . .

10.90 0.3760 0.63 .Q . . . .

11.20 0.3919 0.65 .Q . . . .

11.50 0.4084 0.68 .Q . . . .

11.80 0.4255 0.70 .Q . . . .

12.10 0.4434 0.74 .Q . . . .

12.40 0.4645 0.96 .Q . . . .

12.70 0.4890 1.02 . Q . . . .

13.00 0.5146 1.05 . Q . . . .

13.30 0.5416 1.12 . Q . . . .

13.60 0.5700 1.17 . Q . . . .

13.90 0.6003 1.27 . Q . . . .

14.20 0.6326 1.33 . Q . . . .

14.50 0.6678 1.50 . Q . . . .

14.80 0.7063 1.60 . Q . . . .

15.10 0.7497 1.89 . Q . . . .

15.40 0.7993 2.11 . Q . . . .

Item: 11
1684

15.70 0.8573 2.57 . Q . . . .

16.00 0.9330 3.52 . Q . . . .

16.30 1.1087 10.64 . . .Q . .

16.60 1.2693 2.31 . Q . . . .

16.90 1.3194 1.73 . Q . . . .

17.20 1.3584 1.42 . Q . . . .

17.50 1.3910 1.22 . Q . . . .

17.80 1.4196 1.08 . Q . . . .

18.10 1.4453 0.99 .Q . . . .

18.40 1.4665 0.72 .Q . . . .

18.70 1.4836 0.66 .Q . . . .

19.00 1.4995 0.62 .Q . . . .

19.30 1.5144 0.58 .Q . . . .

19.60 1.5283 0.55 .Q . . . .

19.90 1.5415 0.52 .Q . . . .

20.20 1.5540 0.49 Q . . . .

20.50 1.5659 0.47 Q . . . .

20.80 1.5774 0.45 Q . . . .

21.10 1.5883 0.43 Q . . . .

21.40 1.5988 0.42 Q . . . .

21.70 1.6090 0.40 Q . . . .

22.00 1.6188 0.39 Q . . . .

22.30 1.6283 0.38 Q . . . .

22.60 1.6375 0.37 Q . . . .

22.90 1.6464 0.35 Q . . . .

23.20 1.6551 0.35 Q . . . .

23.50 1.6635 0.34 Q . . . .

23.80 1.6718 0.33 Q . . . .

24.10 1.6798 0.32 Q . . . .

24.40 1.6838 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.8
10% 288.2
20% 72.0
30% 36.0
40% 18.0
50% 18.0
60% 18.0
70% 18.0
80% 18.0
90% 18.0
Item: 11
1685
____________________________________________________________________________ ****************************************************************************

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* PROPOSED 2 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRM2YP.DAT
TIME/DATE OF STUDY: 10:48 09/18/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 2.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) II ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1686
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 785.09 DOWNSTREAM(FEET) = 780.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.168
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.841
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.72 0.25 0.100 69 7.17
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 4.45
TOTAL AREA(ACRES) = 2.72 PEAK FLOW RATE(CFS) = 4.45
**************************************************************************** FLOW PROCESS FROM NODE 1.20 TO NODE 2.20 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 775.54 DOWNSTREAM(FEET) = 774.90 FLOW LENGTH(FEET) = 128.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 12.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.14
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 4.45
PIPE TRAVEL TIME(MIN.) = 0.52 Tc(MIN.) = 7.68
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.68
RAINFALL INTENSITY(INCH/HR) = 1.77
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.72
TOTAL STREAM AREA(ACRES) = 2.72
PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.45
Item: 11
1687
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 220.00
ELEVATION DATA: UPSTREAM(FEET) = 784.75 DOWNSTREAM(FEET) = 780.45 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.776
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.084
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.49 0.25 0.100 69 5.78
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.76
TOTAL AREA(ACRES) = 1.49 PEAK FLOW RATE(CFS) = 2.76
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.78
RAINFALL INTENSITY(INCH/HR) = 2.08
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.49
TOTAL STREAM AREA(ACRES) = 1.49
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.76
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 4.45 7.68 1.769 0.25( 0.03) 0.10 2.7 1.10
2 2.76 5.78 2.084 0.25( 0.03) 0.10 1.5 2.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
Item: 11
1688
1 6.71 5.78 2.084 0.25( 0.02) 0.10 3.5 2.10
2 6.78 7.68 1.769 0.25( 0.03) 0.10 4.2 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 6.78 Tc(MIN.) = 7.68
EFFECTIVE AREA(ACRES) = 4.21 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.2
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.30 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 774.80 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 136.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.59
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.78
PIPE TRAVEL TIME(MIN.) = 0.41 Tc(MIN.) = 8.09
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 8.09
RAINFALL INTENSITY(INCH/HR) = 1.72
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.21
TOTAL STREAM AREA(ACRES) = 4.21
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.78
**************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 136.00
USER SPECIFIED Tc(MIN.) = 5.000
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.264
Item: 11
1689
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 4.65
TOTAL AREA(ACRES) = 2.31 PEAK FLOW RATE(CFS) = 4.65
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 265.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.88
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 4.65
PIPE TRAVEL TIME(MIN.) = 0.64 Tc(MIN.) = 5.64
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 401.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.64
RAINFALL INTENSITY(INCH/HR) = 2.11
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.31
TOTAL STREAM AREA(ACRES) = 2.31
PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.65
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 6.71 6.18 2.004 0.25( 0.02) 0.10 3.5 2.10
1 6.78 8.09 1.717 0.25( 0.03) 0.10 4.2 1.10
2 4.65 5.64 2.112 0.25( 0.03) 0.10 2.3 3.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.

Item: 11
1690
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 11.11 5.64 2.112 0.25( 0.02) 0.10 5.5 3.10
2 11.12 6.18 2.004 0.25( 0.03) 0.10 5.8 2.10
3 10.56 8.09 1.717 0.25( 0.03) 0.10 6.5 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 11.12 Tc(MIN.) = 6.18
EFFECTIVE AREA(ACRES) = 5.84 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.5
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.65 DOWNSTREAM(FEET) = 769.47 FLOW LENGTH(FEET) = 97.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 10.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 11.96
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 11.12
PIPE TRAVEL TIME(MIN.) = 0.14 Tc(MIN.) = 6.32
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 4.40 = 691.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 6.32
RAINFALL INTENSITY(INCH/HR) = 1.98
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 5.84
TOTAL STREAM AREA(ACRES) = 6.52
PEAK FLOW RATE(CFS) AT CONFLUENCE = 11.12
**************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
Item: 11
1691
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 214.00
ELEVATION DATA: UPSTREAM(FEET) = 784.71 DOWNSTREAM(FEET) = 780.40 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.678
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.104
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.36 0.25 0.100 69 5.68
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.55
TOTAL AREA(ACRES) = 1.36 PEAK FLOW RATE(CFS) = 2.55
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 780.40 DOWNSTREAM(FEET) = 775.74 CHANNEL LENGTH THRU SUBAREA(FEET) = 237.00 CHANNEL SLOPE = 0.0197 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.811
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 3.09 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 5.04
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.32 AVERAGE FLOW DEPTH(FEET) = 0.12 TRAVEL TIME(MIN.) = 1.70 Tc(MIN.) = 7.38
SUBAREA AREA(ACRES) = 3.09 SUBAREA RUNOFF(CFS) = 4.97
EFFECTIVE AREA(ACRES) = 4.45 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.4 PEAK FLOW RATE(CFS) = 7.15
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.14 FLOW VELOCITY(FEET/SEC.) = 2.64
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 451.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- Item: 11
1692
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 771.14 DOWNSTREAM(FEET) = 769.66 FLOW LENGTH(FEET) = 296.40 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 14.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.67
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 7.15
PIPE TRAVEL TIME(MIN.) = 1.06 Tc(MIN.) = 8.44
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 8.44
RAINFALL INTENSITY(INCH/HR) = 1.68
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.45
TOTAL STREAM AREA(ACRES) = 4.45
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.15
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 11.11 5.78 2.083 0.25( 0.02) 0.10 5.5 3.10
1 11.12 6.32 1.979 0.25( 0.03) 0.10 5.8 2.10
1 10.56 8.23 1.701 0.25( 0.03) 0.10 6.5 1.10
2 7.15 8.44 1.677 0.25( 0.03) 0.10 4.4 4.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 17.21 5.78 2.083 0.25( 0.02) 0.10 8.6 3.10
2 17.46 6.32 1.979 0.25( 0.03) 0.10 9.2 2.10
3 17.63 8.23 1.701 0.25( 0.03) 0.10 10.9 1.10
4 17.56 8.44 1.677 0.25( 0.03) 0.10 11.0 4.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 17.63 Tc(MIN.) = 8.23
Item: 11
1693
EFFECTIVE AREA(ACRES) = 10.86 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 11.0
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 769.66 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 342.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 18.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.26
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 17.63
PIPE TRAVEL TIME(MIN.) = 0.91 Tc(MIN.) = 9.14
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 1 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 13
---------------------------------------------------------------------------- >>>>>CLEAR THE MAIN-STREAM MEMORY<<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 5.10 TO NODE 5.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 229.00
ELEVATION DATA: UPSTREAM(FEET) = 784.59 DOWNSTREAM(FEET) = 784.09 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 9.099
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.605
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.41 0.25 0.100 69 9.10
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
Item: 11
1694
SUBAREA RUNOFF(CFS) = 0.58
TOTAL AREA(ACRES) = 0.41 PEAK FLOW RATE(CFS) = 0.58
**************************************************************************** FLOW PROCESS FROM NODE 5.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.49 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 142.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 9.0 INCH PIPE IS 3.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 3.33
ESTIMATED PIPE DIAMETER(INCH) = 9.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.58
PIPE TRAVEL TIME(MIN.) = 0.71 Tc(MIN.) = 9.81
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 9.81
RAINFALL INTENSITY(INCH/HR) = 1.54
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 0.41
TOTAL STREAM AREA(ACRES) = 0.41
PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.58
**************************************************************************** FLOW PROCESS FROM NODE 6.10 TO NODE 6.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 142.00
USER SPECIFIED Tc(MIN.) = 5.000
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.264
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.26 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.54
Item: 11
1695
TOTAL AREA(ACRES) = 1.26 PEAK FLOW RATE(CFS) = 2.54
**************************************************************************** FLOW PROCESS FROM NODE 6.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 22.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 3.74
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.54
PIPE TRAVEL TIME(MIN.) = 0.10 Tc(MIN.) = 5.10
LONGEST FLOWPATH FROM NODE 6.10 TO NODE 6.30 = 164.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.10
RAINFALL INTENSITY(INCH/HR) = 2.24
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.26
TOTAL STREAM AREA(ACRES) = 1.26
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.54
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 0.58 9.81 1.538 0.25( 0.03) 0.10 0.4 5.10
2 2.54 5.10 2.239 0.25( 0.03) 0.10 1.3 6.10

Item: 11
1696
PEAK FLOW RATE(CFS) = 2.98 Tc(MIN.) = 5.10
EFFECTIVE AREA(ACRES) = 1.47 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.7
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.11 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 534.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 6.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.48
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.98
PIPE TRAVEL TIME(MIN.) = 1.37 Tc(MIN.) = 6.47
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 3 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 11
---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 2.98 6.47 1.952 0.25( 0.03) 0.10 1.5 6.10
2 2.32 11.27 1.420 0.25( 0.03) 0.10 1.7 5.10
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. ** MEMORY BANK # 1 CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 17.21 6.69 1.915 0.25( 0.02) 0.10 8.6 3.10
2 17.46 7.23 1.832 0.25( 0.03) 0.10 9.2 2.10
3 17.63 9.14 1.602 0.25( 0.03) 0.10 10.9 1.10
4 17.56 9.35 1.581 0.25( 0.03) 0.10 11.0 4.10
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. ** PEAK FLOW RATE TABLE **
Item: 11
1697
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 19.96 6.47 1.952 0.25( 0.02) 0.10 9.8 6.10
2 20.16 6.69 1.915 0.25( 0.02) 0.10 10.1 3.10
3 20.33 7.23 1.832 0.25( 0.03) 0.10 10.7 2.10
4 20.25 9.14 1.602 0.25( 0.03) 0.10 12.4 1.10
5 20.14 9.35 1.581 0.25( 0.03) 0.10 12.6 4.10
6 18.06 11.27 1.420 0.25( 0.03) 0.10 12.6 5.10
TOTAL AREA(ACRES) = 12.6
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 20.33 Tc(MIN.) = 7.229
EFFECTIVE AREA(ACRES) = 10.68 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 12.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 767.66 DOWNSTREAM(FEET) = 766.79 FLOW LENGTH(FEET) = 134.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 18.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.85
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 20.33
PIPE TRAVEL TIME(MIN.) = 0.33 Tc(MIN.) = 7.56
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.56
RAINFALL INTENSITY(INCH/HR) = 1.79
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 10.68
TOTAL STREAM AREA(ACRES) = 12.64
PEAK FLOW RATE(CFS) AT CONFLUENCE = 20.33
**************************************************************************** FLOW PROCESS FROM NODE 7.10 TO NODE 7.20 IS CODE = 21
Item: 11
1698
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 784.05 DOWNSTREAM(FEET) = 779.87 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.409
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.806
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.70 0.25 0.100 69 7.41
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 1.12
TOTAL AREA(ACRES) = 0.70 PEAK FLOW RATE(CFS) = 1.12
**************************************************************************** FLOW PROCESS FROM NODE 7.20 TO NODE 7.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.87 DOWNSTREAM(FEET) = 776.41 CHANNEL LENGTH THRU SUBAREA(FEET) = 323.00 CHANNEL SLOPE = 0.0107 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.465
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.62
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.65 AVERAGE FLOW DEPTH(FEET) = 0.10 TRAVEL TIME(MIN.) = 3.26 Tc(MIN.) = 10.67
SUBAREA AREA(ACRES) = 2.31 SUBAREA RUNOFF(CFS) = 2.99
EFFECTIVE AREA(ACRES) = 3.01 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.0 PEAK FLOW RATE(CFS) = 3.90
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.12 FLOW VELOCITY(FEET/SEC.) = 1.80
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.30 = 653.00 FEET. **************************************************************************** Item: 11
1699
FLOW PROCESS FROM NODE 7.30 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.00 DOWNSTREAM(FEET) = 771.55 FLOW LENGTH(FEET) = 145.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.40
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.90
PIPE TRAVEL TIME(MIN.) = 0.45 Tc(MIN.) = 11.12
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.40 = 798.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 11.12
RAINFALL INTENSITY(INCH/HR) = 1.43
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 3.01
TOTAL STREAM AREA(ACRES) = 3.01
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.90
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 19.96 6.80 1.898 0.25( 0.02) 0.10 9.8 6.10
1 20.16 7.02 1.863 0.25( 0.02) 0.10 10.1 3.10
1 20.33 7.56 1.786 0.25( 0.03) 0.10 10.7 2.10
1 20.25 9.46 1.570 0.25( 0.03) 0.10 12.4 1.10
1 20.14 9.67 1.550 0.25( 0.03) 0.10 12.6 4.10
1 18.06 11.60 1.396 0.25( 0.03) 0.10 12.6 5.10
2 3.90 11.12 1.431 0.25( 0.03) 0.10 3.0 7.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 23.13 6.80 1.898 0.25( 0.02) 0.10 11.6 6.10
2 23.38 7.02 1.863 0.25( 0.02) 0.10 12.0 3.10
Item: 11
1700
3 23.65 7.56 1.786 0.25( 0.03) 0.10 12.7 2.10
4 23.89 9.46 1.570 0.25( 0.03) 0.10 15.0 1.10
5 23.82 9.67 1.550 0.25( 0.03) 0.10 15.2 4.10
6 22.48 11.12 1.431 0.25( 0.03) 0.10 15.6 7.10
7 21.86 11.60 1.396 0.25( 0.03) 0.10 15.6 5.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 23.89 Tc(MIN.) = 9.46
EFFECTIVE AREA(ACRES) = 15.00 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 15.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 15.6 TC(MIN.) = 9.46
EFFECTIVE AREA(ACRES) = 15.00 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 23.89
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 23.13 6.80 1.898 0.25( 0.02) 0.10 11.6 6.10
2 23.38 7.02 1.863 0.25( 0.02) 0.10 12.0 3.10
3 23.65 7.56 1.786 0.25( 0.03) 0.10 12.7 2.10
4 23.89 9.46 1.570 0.25( 0.03) 0.10 15.0 1.10
5 23.82 9.67 1.550 0.25( 0.03) 0.10 15.2 4.10
6 22.48 11.12 1.431 0.25( 0.03) 0.10 15.6 7.10
7 21.86 11.60 1.396 0.25( 0.03) 0.10 15.6 5.10
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1701
____________________________________________________________________________ ****************************************************************************

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* PROPOSED 100 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRM2YP.DAT
TIME/DATE OF STUDY: 10:46 09/18/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 100.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) II ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1702
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 785.09 DOWNSTREAM(FEET) = 780.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.168
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.033
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.72 0.25 0.100 69 7.17
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 12.26
TOTAL AREA(ACRES) = 2.72 PEAK FLOW RATE(CFS) = 12.26
**************************************************************************** FLOW PROCESS FROM NODE 1.20 TO NODE 2.20 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 775.54 DOWNSTREAM(FEET) = 774.90 FLOW LENGTH(FEET) = 128.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 16.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.50
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 12.26
PIPE TRAVEL TIME(MIN.) = 0.39 Tc(MIN.) = 7.56
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.56
RAINFALL INTENSITY(INCH/HR) = 4.88
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.72
TOTAL STREAM AREA(ACRES) = 2.72
PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.26
Item: 11
1703
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 220.00
ELEVATION DATA: UPSTREAM(FEET) = 784.75 DOWNSTREAM(FEET) = 780.45 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.776
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.696
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.49 0.25 0.100 69 5.78
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 7.61
TOTAL AREA(ACRES) = 1.49 PEAK FLOW RATE(CFS) = 7.61
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.78
RAINFALL INTENSITY(INCH/HR) = 5.70
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.49
TOTAL STREAM AREA(ACRES) = 1.49
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.61
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 12.26 7.56 4.884 0.25( 0.03) 0.10 2.7 1.10
2 7.61 5.78 5.696 0.25( 0.03) 0.10 1.5 2.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
Item: 11
1704
1 18.54 5.78 5.696 0.25( 0.03) 0.10 3.6 2.10
2 18.78 7.56 4.884 0.25( 0.03) 0.10 4.2 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 18.78 Tc(MIN.) = 7.56
EFFECTIVE AREA(ACRES) = 4.21 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.2
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.30 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 774.80 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 136.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 19.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.03
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 18.78
PIPE TRAVEL TIME(MIN.) = 0.32 Tc(MIN.) = 7.88
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.88
RAINFALL INTENSITY(INCH/HR) = 4.77
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.21
TOTAL STREAM AREA(ACRES) = 4.21
PEAK FLOW RATE(CFS) AT CONFLUENCE = 18.78
**************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 136.00
USER SPECIFIED Tc(MIN.) = 5.000
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187
Item: 11
1705
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 12.81
TOTAL AREA(ACRES) = 2.31 PEAK FLOW RATE(CFS) = 12.81
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 265.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 14.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.57
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 12.81
PIPE TRAVEL TIME(MIN.) = 0.52 Tc(MIN.) = 5.52
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 401.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.52
RAINFALL INTENSITY(INCH/HR) = 5.85
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.31
TOTAL STREAM AREA(ACRES) = 2.31
PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.81
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 18.54 6.10 5.522 0.25( 0.03) 0.10 3.6 2.10
1 18.78 7.88 4.768 0.25( 0.03) 0.10 4.2 1.10
2 12.81 5.52 5.849 0.25( 0.03) 0.10 2.3 3.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.

Item: 11
1706
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 30.58 5.52 5.849 0.25( 0.03) 0.10 5.5 3.10
2 30.64 6.10 5.522 0.25( 0.03) 0.10 5.9 2.10
3 29.21 7.88 4.768 0.25( 0.03) 0.10 6.5 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 30.64 Tc(MIN.) = 6.10
EFFECTIVE AREA(ACRES) = 5.88 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.5
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.65 DOWNSTREAM(FEET) = 769.47 FLOW LENGTH(FEET) = 97.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 16.4 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 15.17
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 30.64
PIPE TRAVEL TIME(MIN.) = 0.11 Tc(MIN.) = 6.21
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 4.40 = 691.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 6.21
RAINFALL INTENSITY(INCH/HR) = 5.47
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 5.88
TOTAL STREAM AREA(ACRES) = 6.52
PEAK FLOW RATE(CFS) AT CONFLUENCE = 30.64
**************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
Item: 11
1707
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 214.00
ELEVATION DATA: UPSTREAM(FEET) = 784.71 DOWNSTREAM(FEET) = 780.40 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.678
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.752
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.36 0.25 0.100 69 5.68
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 7.01
TOTAL AREA(ACRES) = 1.36 PEAK FLOW RATE(CFS) = 7.01
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 780.40 DOWNSTREAM(FEET) = 775.74 CHANNEL LENGTH THRU SUBAREA(FEET) = 237.00 CHANNEL SLOPE = 0.0197 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.136
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 3.09 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 14.11
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.18 AVERAGE FLOW DEPTH(FEET) = 0.19 TRAVEL TIME(MIN.) = 1.24 Tc(MIN.) = 6.92
SUBAREA AREA(ACRES) = 3.09 SUBAREA RUNOFF(CFS) = 14.21
EFFECTIVE AREA(ACRES) = 4.45 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.4 PEAK FLOW RATE(CFS) = 20.47
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.22 FLOW VELOCITY(FEET/SEC.) = 3.36
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 451.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- Item: 11
1708
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 771.14 DOWNSTREAM(FEET) = 769.66 FLOW LENGTH(FEET) = 296.40 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 21.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.11
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 20.47
PIPE TRAVEL TIME(MIN.) = 0.81 Tc(MIN.) = 7.73
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.73
RAINFALL INTENSITY(INCH/HR) = 4.82
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.45
TOTAL STREAM AREA(ACRES) = 4.45
PEAK FLOW RATE(CFS) AT CONFLUENCE = 20.47
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 30.58 5.62 5.785 0.25( 0.03) 0.10 5.5 3.10
1 30.64 6.21 5.467 0.25( 0.03) 0.10 5.9 2.10
1 29.21 7.99 4.731 0.25( 0.03) 0.10 6.5 1.10
2 20.47 7.73 4.821 0.25( 0.03) 0.10 4.4 4.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 48.47 5.62 5.785 0.25( 0.03) 0.10 8.8 3.10
2 49.29 6.21 5.467 0.25( 0.03) 0.10 9.5 2.10
3 49.89 7.73 4.821 0.25( 0.03) 0.10 10.9 4.10
4 49.30 7.99 4.731 0.25( 0.03) 0.10 11.0 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 49.89 Tc(MIN.) = 7.73
Item: 11
1709
EFFECTIVE AREA(ACRES) = 10.88 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 11.0
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 769.66 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 342.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 39.0 INCH PIPE IS 27.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.09
ESTIMATED PIPE DIAMETER(INCH) = 39.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 49.89
PIPE TRAVEL TIME(MIN.) = 0.70 Tc(MIN.) = 8.43
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 1 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 13
---------------------------------------------------------------------------- >>>>>CLEAR THE MAIN-STREAM MEMORY<<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 5.10 TO NODE 5.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 229.00
ELEVATION DATA: UPSTREAM(FEET) = 784.59 DOWNSTREAM(FEET) = 784.09 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 9.099
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.390
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.41 0.25 0.100 69 9.10
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
Item: 11
1710
SUBAREA RUNOFF(CFS) = 1.61
TOTAL AREA(ACRES) = 0.41 PEAK FLOW RATE(CFS) = 1.61
**************************************************************************** FLOW PROCESS FROM NODE 5.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.49 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 142.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 5.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.30
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 1.61
PIPE TRAVEL TIME(MIN.) = 0.55 Tc(MIN.) = 9.65
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 9.65
RAINFALL INTENSITY(INCH/HR) = 4.25
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 0.41
TOTAL STREAM AREA(ACRES) = 0.41
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.61
**************************************************************************** FLOW PROCESS FROM NODE 6.10 TO NODE 6.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 142.00
USER SPECIFIED Tc(MIN.) = 5.000
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.26 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 6.99
Item: 11
1711
TOTAL AREA(ACRES) = 1.26 PEAK FLOW RATE(CFS) = 6.99
**************************************************************************** FLOW PROCESS FROM NODE 6.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 22.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 14.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.67
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.99
PIPE TRAVEL TIME(MIN.) = 0.08 Tc(MIN.) = 5.08
LONGEST FLOWPATH FROM NODE 6.10 TO NODE 6.30 = 164.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.08
RAINFALL INTENSITY(INCH/HR) = 6.13
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.26
TOTAL STREAM AREA(ACRES) = 1.26
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.99
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 1.61 9.65 4.245 0.25( 0.03) 0.10 0.4 5.10
2 6.99 5.08 6.132 0.25( 0.03) 0.10 1.3 6.10

Item: 11
1712
PEAK FLOW RATE(CFS) = 8.21 Tc(MIN.) = 5.08
EFFECTIVE AREA(ACRES) = 1.48 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.7
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.11 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 534.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 11.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.11
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 8.21
PIPE TRAVEL TIME(MIN.) = 1.10 Tc(MIN.) = 6.18
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 3 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 11
---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 8.21 6.18 5.482 0.25( 0.03) 0.10 1.5 6.10
2 6.44 10.79 3.982 0.25( 0.03) 0.10 1.7 5.10
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. ** MEMORY BANK # 1 CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 48.47 6.33 5.405 0.25( 0.03) 0.10 8.8 3.10
2 49.29 6.91 5.140 0.25( 0.03) 0.10 9.5 2.10
3 49.89 8.43 4.586 0.25( 0.03) 0.10 10.9 4.10
4 49.30 8.69 4.507 0.25( 0.03) 0.10 11.0 1.10
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. ** PEAK FLOW RATE TABLE **
Item: 11
1713
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 56.17 6.18 5.482 0.25( 0.03) 0.10 10.0 6.10
2 56.62 6.33 5.405 0.25( 0.03) 0.10 10.3 3.10
3 57.22 6.91 5.140 0.25( 0.03) 0.10 11.0 2.10
4 57.23 8.43 4.586 0.25( 0.03) 0.10 12.4 4.10
5 56.54 8.69 4.507 0.25( 0.03) 0.10 12.6 1.10
6 49.96 10.79 3.982 0.25( 0.03) 0.10 12.6 5.10
TOTAL AREA(ACRES) = 12.6
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 57.23 Tc(MIN.) = 8.433
EFFECTIVE AREA(ACRES) = 12.45 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 12.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 767.66 DOWNSTREAM(FEET) = 766.79 FLOW LENGTH(FEET) = 134.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 39.0 INCH PIPE IS 28.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.82
ESTIMATED PIPE DIAMETER(INCH) = 39.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 57.23
PIPE TRAVEL TIME(MIN.) = 0.25 Tc(MIN.) = 8.69
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 8.69
RAINFALL INTENSITY(INCH/HR) = 4.51
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 12.45
TOTAL STREAM AREA(ACRES) = 12.64
PEAK FLOW RATE(CFS) AT CONFLUENCE = 57.23
**************************************************************************** FLOW PROCESS FROM NODE 7.10 TO NODE 7.20 IS CODE = 21
Item: 11
1714
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 784.05 DOWNSTREAM(FEET) = 779.87 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.409
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.939
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.70 0.25 0.100 69 7.41
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 3.10
TOTAL AREA(ACRES) = 0.70 PEAK FLOW RATE(CFS) = 3.10
**************************************************************************** FLOW PROCESS FROM NODE 7.20 TO NODE 7.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.87 DOWNSTREAM(FEET) = 776.41 CHANNEL LENGTH THRU SUBAREA(FEET) = 323.00 CHANNEL SLOPE = 0.0107 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.168
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 7.42
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.11 AVERAGE FLOW DEPTH(FEET) = 0.16 TRAVEL TIME(MIN.) = 2.56 Tc(MIN.) = 9.96
SUBAREA AREA(ACRES) = 2.31 SUBAREA RUNOFF(CFS) = 8.61
EFFECTIVE AREA(ACRES) = 3.01 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.0 PEAK FLOW RATE(CFS) = 11.22
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.20 FLOW VELOCITY(FEET/SEC.) = 2.36
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.30 = 653.00 FEET. **************************************************************************** Item: 11
1715
FLOW PROCESS FROM NODE 7.30 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.00 DOWNSTREAM(FEET) = 771.55 FLOW LENGTH(FEET) = 145.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 13.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.00
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 11.22
PIPE TRAVEL TIME(MIN.) = 0.35 Tc(MIN.) = 10.31
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.40 = 798.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 10.31
RAINFALL INTENSITY(INCH/HR) = 4.09
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 3.01
TOTAL STREAM AREA(ACRES) = 3.01
PEAK FLOW RATE(CFS) AT CONFLUENCE = 11.22
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 56.17 6.43 5.357 0.25( 0.03) 0.10 10.0 6.10
1 56.62 6.58 5.285 0.25( 0.03) 0.10 10.3 3.10
1 57.22 7.16 5.035 0.25( 0.03) 0.10 11.0 2.10
1 57.23 8.69 4.509 0.25( 0.03) 0.10 12.4 4.10
1 56.54 8.95 4.433 0.25( 0.03) 0.10 12.6 1.10
1 49.96 11.05 3.927 0.25( 0.03) 0.10 12.6 5.10
2 11.22 10.31 4.087 0.25( 0.03) 0.10 3.0 7.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 65.36 6.43 5.357 0.25( 0.03) 0.10 11.9 6.10
2 65.90 6.58 5.285 0.25( 0.03) 0.10 12.2 3.10
Item: 11
1716
3 66.84 7.16 5.035 0.25( 0.03) 0.10 13.1 2.10
4 67.67 8.69 4.509 0.25( 0.03) 0.10 15.0 4.10
5 67.11 8.95 4.433 0.25( 0.03) 0.10 15.2 1.10
6 63.51 10.31 4.087 0.25( 0.03) 0.10 15.6 7.10
7 60.74 11.05 3.927 0.25( 0.03) 0.10 15.6 5.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 67.67 Tc(MIN.) = 8.69
EFFECTIVE AREA(ACRES) = 14.98 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 15.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 15.6 TC(MIN.) = 8.69
EFFECTIVE AREA(ACRES) = 14.98 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 67.67
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 65.36 6.43 5.357 0.25( 0.03) 0.10 11.9 6.10
2 65.90 6.58 5.285 0.25( 0.03) 0.10 12.2 3.10
3 66.84 7.16 5.035 0.25( 0.03) 0.10 13.1 2.10
4 67.67 8.69 4.509 0.25( 0.03) 0.10 15.0 4.10
5 67.11 8.95 4.433 0.25( 0.03) 0.10 15.2 1.10
6 63.51 10.31 4.087 0.25( 0.03) 0.10 15.6 7.10
7 60.74 11.05 3.927 0.25( 0.03) 0.10 15.6 5.10
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1717
_________________________________________________________________ ___________
***************************************************************** ***********

SMALL AREA UNIT HYDROGRAPH MODEL
================================================================= ===========
(C) Copyright 1989-2016 Advanced Engineering Software
(aes)
Ver. 23.0 Release Date: 07/01/2016 License ID
1499
Analysis prepared by:

***************************************************************** ***********
---------------------------------------------------------------- ------------
Problem Descriptions:

COSTCO FOOTHILL RANCH
PROPOSED 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------- ------------
RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 15.65
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.157
TIME OF CONCENTRATION(MIN.) = 9.46

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------- 1 Item: 11
1718
------------
TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 2.39
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.28
***************************************************************** ***********
TIME VOLUME Q 0. 7.5 15.0 22.5

30.0 (HOURS) (AF) (CFS)
---------------------------------------------------------------- ------------

0.08 0.0014 0.45
Q . . . .

0.23 0.0073 0.45
Q . . . .

0.39 0.0132 0.46
Q . . . .

0.55 0.0191 0.46
Q . . . .

0.71 0.0251 0.46
Q . . . .

0.86 0.0312 0.46
Q . . . .

1.02 0.0372 0.47
Q . . . .

1.18 0.0433 0.47
Q . . . .

1.34 0.0495 0.47
Q . . . .

1.49 0.0557 0.48
Q . . . .

1.65 0.0619 0.48
Q . . . .

1.81 0.0681 0.48
Q . . . .

1.97 0.0745 0.49
Q . . . .

2.13 0.0808 0.49
Q . . . .

2.28 0.0872 0.49
Q . . . .

2.44 0.0937 0.50
Q . . . .

2.60 0.1002 0.50
Q . . . .

2.76 0.1067 0.50
Q . . . .

2.91 0.1133 0.51
Q . . . .

3.07 0.1199 0.51
2 Item: 11
1719
Q . . . .

3.23 0.1266 0.52
Q . . . .

3.39 0.1334 0.52
Q . . . .

3.54 0.1401 0.52
Q . . . .

3.70 0.1470 0.53
Q . . . .

3.86 0.1539 0.53
Q . . . .

4.02 0.1609 0.54
Q . . . .

4.18 0.1679 0.54
Q . . . .

4.33 0.1749 0.54
Q . . . .

4.49 0.1821 0.55
Q . . . .

4.65 0.1893 0.55
Q . . . .

4.81 0.1965 0.56
Q . . . .

4.96 0.2038 0.56
Q . . . .

5.12 0.2112 0.57
Q . . . .

5.28 0.2187 0.57
Q . . . .

5.44 0.2262 0.58
Q . . . .

5.59 0.2338 0.58
Q . . . .

5.75 0.2414 0.59
Q . . . .

5.91 0.2492 0.60
Q . . . .

6.07 0.2570 0.60
Q . . . .

6.22 0.2648 0.61
Q . . . .

6.38 0.2728 0.62
Q . . . .

6.54 0.2808 0.62
Q . . . .

6.70 0.2890 0.63
Q . . . .

6.86 0.2972 0.63
Q . . . .

7.01 0.3055 0.64
Q . . . .

7.17 0.3139 0.65
3 Item: 11
1720
Q . . . .

7.33 0.3224 0.66
Q . . . .

7.49 0.3309 0.66
Q . . . .

7.64 0.3396 0.67
Q . . . .

7.80 0.3484 0.68
Q . . . .

7.96 0.3573 0.69
Q . . . .

8.12 0.3663 0.69
Q . . . .

8.27 0.3754 0.70
Q . . . .

8.43 0.3846 0.71
Q . . . .

8.59 0.3939 0.72
Q . . . .

8.75 0.4034 0.73
Q . . . .

8.90 0.4130 0.74
Q . . . .

9.06 0.4227 0.75
Q . . . .

9.22 0.4325

0.76 .Q . . . .

9.38 0.4425

0.77 .Q . . . .

9.54 0.4527

0.79 .Q . . . .

9.69 0.4630

0.79 .Q . . . .

9.85 0.4734

0.81 .Q . . . .

10.01 0.4840

0.82 .Q . . . .

10.17 0.4948

0.84 .Q . . . .

10.32 0.5058

0.85 .Q . . . .

10.48 0.5170

0.87 .Q . . . .

10.64 0.5283

0.88 .Q . . . .

10.80 0.5399

0.90 .Q . . . .

10.95 0.5517

0.91 .Q . . . .

11.11 0.5637

0.93 .Q . . . .

11.27 0.5759
4 Item: 11
1721

0.95 .Q . . . .

11.43 0.5884

0.97 .Q . . . .

11.59 0.6012

0.99 .Q . . . .

11.74 0.6142

1.02 .Q . . . .

11.90 0.6275

1.03 .Q . . . .

12.06 0.6413

1.08 .Q . . . .

12.22 0.6569

1.31 .Q . . . .

12.37 0.6742

1.35 .Q . . . .

12.53 0.6920

1.37 .Q . . . .

12.69 0.7102

1.42 .Q . . . .

12.85 0.7289

1.44 .Q . . . .

13.00 0.7480

1.50 .Q . . . .

13.16 0.7677 1.53 .

Q . . . .

13.32 0.7880 1.59 .

Q . . . .

13.48 0.8089 1.62 .

Q . . . .

13.63 0.8305 1.69 .

Q . . . .

13.79 0.8529 1.74 .

Q . . . .

13.95 0.8761 1.83 .

Q . . . .

14.11 0.9002 1.88 .

Q . . . .

14.27 0.9259 2.06 .

Q . . . .

14.42 0.9531 2.13 .

Q . . . .

14.58 0.9818 2.28 .

Q . . . .

14.74 1.0120 2.36 .

Q . . . .

14.90 1.0442 2.57 .

Q . . . .

15.05 1.0786 2.70 .

Q . . . .

15.21 1.1158 3.02 .

Q . . . .

15.37 1.1565 3.23 .
5 Item: 11
1722
Q . . . .

15.53 1.1990 3.30 .

Q . . . .

15.68 1.2448 3.72 .

Q . . . .

15.84 1.3043 5.41 .

Q . . . .

16.00 1.3877 7.38 .

Q. . . .

16.16 1.5799 22.12 . . .

Q. .

16.32 1.7524 4.35 .

Q . . . .

16.47 1.8023 3.31 .

Q . . . .

16.63 1.8424 2.85 .

Q . . . .

16.79 1.8770 2.46 .

Q . . . .

16.95 1.9073 2.20 .

Q . . . .

17.10 1.9347 2.00 .

Q . . . .

17.26 1.9593 1.78 .

Q . . . .

17.42 1.9817 1.66 .

Q . . . .

17.58 2.0026 1.56 .

Q . . . .

17.73 2.0223

1.47 .Q . . . .

17.89 2.0410

1.40 .Q . . . .

18.05 2.0588

1.33 .Q . . . .

18.21 2.0743

1.05 .Q . . . .

18.36 2.0877

1.00 .Q . . . .

18.52 2.1004

0.96 .Q . . . .

18.68 2.1127

0.92 .Q . . . .

18.84 2.1245

0.89 .Q . . . .

19.00 2.1358

0.86 .Q . . . .

19.15 2.1468

0.83 .Q . . . .

19.31 2.1574

0.80 .Q . . . .

19.47 2.1677
6 Item: 11
1723

0.78 .Q . . . .

19.63 2.1777

0.76 .Q . . . .

19.78 2.1874 0.74
Q . . . .

19.94 2.1969 0.72
Q . . . .

20.10 2.2061 0.70
Q . . . .

20.26 2.2151 0.68
Q . . . .

20.41 2.2239 0.67
Q . . . .

20.57 2.2325 0.65
Q . . . .

20.73 2.2409 0.64
Q . . . .

20.89 2.2491 0.62
Q . . . .

21.05 2.2571 0.61
Q . . . .

21.20 2.2650 0.60
Q . . . .

21.36 2.2727 0.59
Q . . . .

21.52 2.2803 0.58
Q . . . .

21.68 2.2878 0.57
Q . . . .

21.83 2.2951 0.56
Q . . . .

21.99 2.3023 0.55
Q . . . .

22.15 2.3093 0.54
Q . . . .

22.31 2.3163 0.53
Q . . . .

22.46 2.3231 0.52
Q . . . .

22.62 2.3299 0.51
Q . . . .

22.78 2.3365 0.51
Q . . . .

22.94 2.3431 0.50
Q . . . .

23.09 2.3495 0.49
Q . . . .

23.25 2.3559 0.48
Q . . . .

23.41 2.3621 0.48
Q . . . .

23.57 2.3683 0.47
7 Item: 11
1724
Q . . . .

23.73 2.3744 0.47
Q . . . .

23.88 2.3805 0.46
Q . . . .

24.04 2.3864 0.45
Q . . . .

24.20 2.3894 0.00
Q . . . .
---------------------------------------------------------------- ------------
----------------------------------------------------------------- ---------------
TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1447.4
10% 141.9
20% 28.4
30% 18.9
40% 9.5
50% 9.5
60% 9.5
70% 9.5
80% 9.5
90% 9.5
8 Item: 11
1725
_________________________________________________________________ ___________
***************************************************************** ***********

SMALL AREA UNIT HYDROGRAPH MODEL
================================================================= ===========
(C) Copyright 1989-2016 Advanced Engineering Software
(aes)
Ver. 23.0 Release Date: 07/01/2016 License ID
1499
Analysis prepared by:

***************************************************************** ***********
---------------------------------------------------------------- ------------
Problem Descriptions:

COSTCO FOOTHILL RANCH
PROPOSED 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------- ------------
RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 15.65
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.157
TIME OF CONCENTRATION(MIN.) = 8.69

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------- 1 Item: 11
1726
------------
TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 6.56
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.78
***************************************************************** ***********
TIME VOLUME Q 0. 17.5 35.0 52.5

70.0 (HOURS) (AF) (CFS)
---------------------------------------------------------------- ------------

0.07 0.0000 0.00
Q . . . .

0.21 0.0074 1.24
Q . . . .

0.36 0.0222 1.24
Q . . . .

0.50 0.0371 1.25
Q . . . .

0.65 0.0521 1.26
Q . . . .

0.79 0.0672 1.27
Q . . . .

0.94 0.0824 1.27
Q . . . .

1.08 0.0976 1.28
Q . . . .

1.23 0.1130 1.29
Q . . . .

1.37 0.1284 1.30
Q . . . .

1.52 0.1440 1.30
Q . . . .

1.66 0.1596 1.31
Q . . . .

1.81 0.1754 1.32
Q . . . .

1.95 0.1912 1.33
Q . . . .

2.10 0.2072 1.33
Q . . . .

2.24 0.2232 1.35
Q . . . .

2.39 0.2394 1.35
Q . . . .

2.53 0.2556 1.36
Q . . . .

2.68 0.2720 1.37
Q . . . .

2.82 0.2885 1.38
2 Item: 11
1727
Q . . . .

2.97 0.3051 1.39
Q . . . .

3.11 0.3218 1.40
Q . . . .

3.25 0.3386 1.41
Q . . . .

3.40 0.3555 1.42
Q . . . .

3.54 0.3726 1.43
Q . . . .

3.69 0.3898 1.44
Q . . . .

3.83 0.4071 1.45
Q . . . .

3.98 0.4246 1.46
Q . . . .

4.12 0.4421 1.47
Q . . . .

4.27 0.4599 1.49
Q . . . .

4.41 0.4777 1.49
Q . . . .

4.56 0.4957 1.51
Q . . . .

4.70 0.5138 1.52
Q . . . .

4.85 0.5321 1.53
Q . . . .

4.99 0.5505 1.54
Q . . . .

5.14 0.5691 1.56
Q . . . .

5.28 0.5878 1.57
Q . . . .

5.43 0.6067 1.59
Q . . . .

5.57 0.6257 1.60
Q . . . .

5.72 0.6449 1.61
Q . . . .

5.86 0.6643 1.62
Q . . . .

6.01 0.6839 1.64
Q . . . .

6.15 0.7036 1.65
Q . . . .

6.30 0.7235 1.67
Q . . . .

6.44 0.7436 1.68
Q . . . .

6.59 0.7639 1.71
3 Item: 11
1728
Q . . . .

6.73 0.7844 1.72
Q . . . .

6.88 0.8050 1.74
Q . . . .

7.02 0.8259

1.75 .Q . . . .

7.17 0.8470

1.77 .Q . . . .

7.31 0.8683

1.79 .Q . . . .

7.45 0.8898

1.81 .Q . . . .

7.60 0.9116

1.82 .Q . . . .

7.74 0.9336

1.85 .Q . . . .

7.89 0.9558

1.86 .Q . . . .

8.03 0.9783

1.89 .Q . . . .

8.18 1.0010

1.91 .Q . . . .

8.32 1.0240

1.94 .Q . . . .

8.47 1.0473

1.95 .Q . . . .

8.61 1.0708

1.98 .Q . . . .

8.76 1.0946

2.00 .Q . . . .

8.90 1.1187

2.03 .Q . . . .

9.05 1.1432

2.05 .Q . . . .

9.19 1.1679

2.09 .Q . . . .

9.34 1.1930

2.10 .Q . . . .

9.48 1.2184

2.14 .Q . . . .

9.63 1.2441

2.16 .Q . . . .

9.77 1.2703

2.20 .Q . . . .

9.92 1.2968

2.22 .Q . . . .

10.06 1.3237

2.27 .Q . . . .

10.21 1.3509

2.29 .Q . . . .

10.35 1.3787
4 Item: 11
1729

2.34 .Q . . . .

10.50 1.4068

2.36 .Q . . . .

10.64 1.4354

2.42 .Q . . . .

10.79 1.4645

2.44 .Q . . . .

10.93 1.4941

2.50 .Q . . . .

11.08 1.5243

2.53 .Q . . . .

11.22 1.5549

2.59 .Q . . . .

11.37 1.5862

2.63 .Q . . . .

11.51 1.6180

2.70 .Q . . . .

11.65 1.6505

2.73 .Q . . . .

11.80 1.6836

2.81 .Q . . . .

11.94 1.7175

2.85 .Q . . . .

12.09 1.7540

3.25 .Q . . . .

12.23 1.7958 3.73 .

Q . . . .

12.38 1.8411 3.83 .

Q . . . .

12.52 1.8873 3.89 .

Q . . . .

12.67 1.9346 4.00 .

Q . . . .

12.81 1.9829 4.06 .

Q . . . .

12.96 2.0323 4.20 .

Q . . . .

13.10 2.0830 4.27 .

Q . . . .

13.25 2.1349 4.42 .

Q . . . .

13.39 2.1883 4.50 .

Q . . . .

13.54 2.2432 4.68 .

Q . . . .

13.68 2.2998 4.77 .

Q . . . .

13.83 2.3582 4.99 .

Q . . . .

13.97 2.4186 5.10 .

Q . . . .

14.12 2.4814 5.38 .
5 Item: 11
1730
Q . . . .

14.26 2.5468 5.54 .

Q . . . .

14.41 2.6150 5.86 .

Q . . . .

14.55 2.6863 6.05 .

Q . . . .

14.70 2.7613 6.48 .

Q . . . .

14.84 2.8403 6.73 .

Q . . . .

14.99 2.9244 7.33 .

Q . . . .

15.13 3.0143 7.69 .

Q . . . .

15.28 3.1118 8.60 .

Q . . . .

15.42 3.2183 9.19 .

Q . . . .

15.57 3.3309 9.62 .

Q . . . .

15.71 3.4534 10.84 .

Q . . . .

15.86 3.6106 15.43 .

Q . . . .

16.00 3.8289 21.06 . .

Q . . .

16.14 4.3353 63.54 . . . .

Q .

16.29 4.7910 12.60 .

Q . . . .

16.43 4.9192 8.83 .

Q . . . .

16.58 5.0206 8.11 .

Q . . . .

16.72 5.1111 7.01 .

Q . . . .

16.87 5.1905 6.25 .

Q . . . .

17.01 5.2620 5.69 .

Q . . . .

17.16 5.3274 5.23 .

Q . . . .

17.30 5.3878 4.88 .

Q . . . .

17.45 5.4445 4.59 .

Q . . . .

17.59 5.4979 4.34 .

Q . . . .

17.74 5.5486 4.13 .

Q . . . .

17.88 5.5969 3.94 .
6 Item: 11
1731
Q . . . .

18.03 5.6432 3.78 .

Q . . . .

18.17 5.6831

2.89 .Q . . . .

18.32 5.7170

2.77 .Q . . . .

18.46 5.7495

2.66 .Q . . . .

18.61 5.7807

2.56 .Q . . . .

18.75 5.8109

2.47 .Q . . . .

18.90 5.8400

2.39 .Q . . . .

19.04 5.8681

2.32 .Q . . . .

19.19 5.8954

2.25 .Q . . . .

19.33 5.9219

2.18 .Q . . . .

19.48 5.9477

2.12 .Q . . . .

19.62 5.9728

2.07 .Q . . . .

19.77 5.9972

2.02 .Q . . . .

19.91 6.0210

1.97 .Q . . . .

20.06 6.0443

1.92 .Q . . . .

20.20 6.0670

1.88 .Q . . . .

20.34 6.0892

1.84 .Q . . . .

20.49 6.1110

1.80 .Q . . . .

20.63 6.1323

1.76 .Q . . . .

20.78 6.1532 1.73
Q . . . .

20.92 6.1737 1.69
Q . . . .

21.07 6.1938 1.66
Q . . . .

21.21 6.2135 1.63
Q . . . .

21.36 6.2329 1.60
Q . . . .

21.50 6.2519 1.58
Q . . . .

21.65 6.2706 1.55
7 Item: 11
1732
Q . . . .

21.79 6.2891 1.53
Q . . . .

21.94 6.3072 1.50
Q . . . .

22.08 6.3250 1.48
Q . . . .

22.23 6.3426 1.46
Q . . . .

22.37 6.3599 1.44
Q . . . .

22.52 6.3770 1.42
Q . . . .

22.66 6.3938 1.40
Q . . . .

22.81 6.4104 1.38
Q . . . .

22.95 6.4268 1.36
Q . . . .

23.10 6.4429 1.34
Q . . . .

23.24 6.4589 1.32
Q . . . .

23.39 6.4746 1.31
Q . . . .

23.53 6.4902 1.29
Q . . . .

23.68 6.5055 1.28
Q . . . .

23.82 6.5207 1.26
Q . . . .

23.97 6.5357 1.25
Q . . . .

24.11 6.5505 1.23
Q . . . .

24.26 6.5579 0.00
Q . . . .
---------------------------------------------------------------- ------------
----------------------------------------------------------------- ---------------
TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1442.5
10% 130.3
20% 26.1
8 Item: 11
1733
30% 17.4
40% 8.7
50% 8.7
60% 8.7
70% 8.7
80% 8.7
90% 8.7
9 Item: 11
1734
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Friday, 05 / 16 / 2025 Hyd. No. 2
Basin Routing
Hydrograph type = Reservoir Peak discharge = 21.66 cfs
Storm frequency = 2 yrs Time to peak = 15.30 hrs
Time interval = 9 min Hyd. volume = 98,411 cuft
Inflow hyd. No. = 1 - STORM INFLOW Max. Elevation = 101.80 ft Reservoir name = Basin Max. Storage = 1,153 cuft
Storage Indication method used.

4.2 6.3 8.4 10.5 12.6 14.7 16.8 18.9 21.0 23.1
Q (cfs)

0.00 0.00

4.00 4.00

8.00 8.00

12.00 12.00

16.00 16.00

20.00 20.00

24.00 24.00

28.00 28.00
Q (cfs)
Time (hrs)
Basin Routing
Hyd. No. 2 -- 2 Year
Hyd No. 2 Hyd No. 1 Total storage used = 1,153 cuft
Item: 11
1735
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 31
Attachment D – BMP Fact Sheet
Item: 11
1736
Item: 11
1737
Item: 11
1738
Item: 11
1739
Item: 11
1740
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 32
Attachment E – Geotechnical Report
Item: 11
1741
25003229.001A/LH25R178197 Page 1 of 1 February 14, 2025 © 2025 Kleinfelder www.kleinfelder.com
24411 Ridge Route Dr. Suite 225, Laguna Hills 92653 p | 949.727.4466 f | 949.727.9242 February 14, 2025
Kleinfelder Project No. 25003229.001A
Costco Wholesale
9 Corporate Park
Irvine, California 92606
Attention: Mr. Michael Okuma
AVP Real Estate Development
SUBJECT: DRAFT Geotechnical Study
Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
CW# 24-1218
Dear Mr. Okuma:

Kleinfelder is pleased to present this report summarizing our draft geotechnical study for the proposed Costco Wholesale Warehouse located at 26602 Towne Centre Drive in Foothill Ranch, California. The conclusions and recommendations presented in this report are subject to the limitations presented in Section 7.

We appreciate the opportunity to provide geotechnical engineering services to you on this project.

If you have any questions regarding this report or if we can be of further service, please do not hesitate to contact Brian Crystal 949.727.4466, or Andy Franks, Kleinfelder’s Client Account Manager for Costco at 480.650.4905.

Sincerely,

KLEINFELDER
Hector Marquez, PE Brian E. Crystal, PE, GE
Project Engineer Senior Project Manager
DRAFT
Item: 11
1742
Copyright 2025 Kleinfelder
All Rights Reserved

ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC PROJECT FOR WHICH THIS REPORT WAS PREPARED.
25003229.001A/LH25R178197 Page i of iv February 14, 2025 © 2025 Kleinfelder www.kleinfelder.com

DRAFT GEOTECHNICAL STUDY

PROPOSED COSTCO WHOLESALE WAREHOUSE

AND FUEL FACILITY
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
CW# 24-1218
KLEINFELDER PROJECT NO. 25003229.001A
FEBRUARY 14, 2025
DRAFT
Item: 11
1743
25003229.001A/LH25R178197 Page ii of iv February 14, 2025 © 2025 Kleinfelder www.kleinfelder.com
A Report Prepared for:

Costco Wholesale
9 Corporate Park
Irvine, California 92606
Attention: Mr. Michael Okuma
AVP Real Estate Development

DRAFT GEOTECHNICAL STUDY

PROPOSED COSTCO WHOLESALE WAREHOUSE AND FUEL FACILITY
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
CW# 24-1218
Hector Marquez, PE
Project Engineer
Brian E. Crystal, PE, GE
Senior Project Manager

KLEINFELDER
24411 Ridge Route Drive, Suite 225
Laguna Hills, California
Phone: 949.727.4466
Fax: 949.727.9242
February 14, 2025
Kleinfelder Project No. 25003229.001A
DRAFT
Item: 11
1744
February 14, 2025 Page 1 of 4
Geotechnical Investigation Summary Checklist for Costco Wholesale Projects
General Information
Costco Real Estate Main Contact: Michael Okuma
Geotechnical Main Contact: Brian Crystal (949.585.3113) Geotechnical Engineer of Record: Kleinfelder
Project Location: 26602 Towne Centre Drive, Foothill Ranch, CA CW#: 24-1218
Warehouse #: N/A
Report Date: February 14, 2025
Consultant Project/Document Number: 25003229.001A/LH25R178197 Addendums (List):

Report Purpose: ☐ Preliminary ☒ Draft ☐ Final ☐ Addendum/Revision Yes
No
or
NA
Describe/ Comments Report
Section
Pre-existing Conditions/Information
Developer provided geotechnical report (describe): ☐ ☒
Pre-existing development (describe) ☒ ☐ Existing commercial development 2.1 Foundation type (describe): ☐ ☒
Performance Issues (describe): ☐ ☒
Environmental Issues (describe) ☐ ☒
Site Grading Records (stripping,compaction test
results,field reports, etc.) ☐ ☒
Typical Building Structural Design Criteria
Other (describe): ☒ ☐ New Costco Warehouse 1.1
Building size (describe): ☒ ☐
166,067-square-foot Costco
Wholesale Warehouse and Fuel
Facility

1.1 Typical wall loading
3 kips / foot* (Metal Buildings) ☐ ☒

4.5 kips / foot* (CMU or pre-cast) ☒ ☐ Both CMU and Metal 1.1 Typical column loading
120 kips in non-snow regions ☐ ☒ Up to 250 kips for rooftop parking 1.1 150 kips in snow regions ☐ ☒
Typical canopy loading: 50 kips ☒ ☐ 1.1
Typical floor slab loading
500 pounds per square foot, (psf, total) ☒ ☐ 1.1
250 psf (dead) at rack areas ☒ ☐
150 psf (dead) at non-rack areas ☒ ☐
350 psf (live) ☒ ☐
Paving Design (20 year life)
Heavy Duty paving shall accommodate 30 trucks per
day (Traffic Index of 7.0) ☒ ☐ 4.8
Light Duty paving shall accommodate 6,600 cars per
day (Traffic Index of 5.0) ☒ ☐ 4.8
Performance Grade (PG) binder oil identified for local
climate conditions ☒ ☐ PG 64-10 4.8.3
Yes
No
or
NA
Describe/ Comments Report
Section
DRAFT
Item: 11
1745
February 14, 2025 Page 2 of 4
Site Grading Conditions/Assumptions
Deviations to Typical Criteria (list/describe): ☐ ☒
Design Finished Floor Elevation (FFE) (describe): ☐ ☒
Not available at the time of this
report. 1.1
Basis for FFE (assumed, per Civil) (describe): ☐ ☒
Effects of change to assumed FFE (describe): ☐ ☒
Maximum anticipated cuts (describe): ☒ ☐ Assumed less than 5 feet 1.1 Maximum anticipated fills (describe): ☒ ☐ Assumed less than 5 feet 1.1 Cross sections prepared for sites that are not essentially flat ☐ ☒ Will provide with Final Report
Amount of import/export anticipated (describe): ☐ ☒ 1.1 Frost Depth (describe): ☐ ☒
Retaining walls
Number of walls (describe): ☐ ☒
Height/Length of walls (describe): ☐ ☒
Wall construction/type (describe): ☐ ☒
Cut/fill transition in pad (describe): ☐ ☒
Offsite Improvements (describe) ☐ ☒
Fieldwork/Results
Costco Due Diligence Design Criteria
Version (describe): ☒ ☐ Version 2022, dated Oct. 28, 2022 1.1 Followed Criteria? ☒ ☐
Deviations to standard investigation (describe): ☐ ☒
Groundwater
Depth (describe): ☒ ☐
Groundwater was not encountered
during our investigation which was
drilled to an approximate depth of
49½ feet bgs.

3.3 Perched ☒ ☐
Perched groundwater should be
expected during and following
periods of rainfall

3.3 Expected seasonal fluctuation (describe): ☐ ☒
Piezometers installed? ☐ ☒
Unusual/Challenging Soils conditions encountered
Moisture-sensitive soils ☐ ☒
Undocumented fill ☒ ☐
Artificial fill associated with
previous grading at the site was
observed at depths ranging from
approximately 4 to 9½ feet bgs.

3.2 Unsuitable soils (require removal) ☒ ☐ Unsuitable fill soils 5.2.2 Wet soils ☐ ☒
Debris ☐ ☒
Bedrock/potential non-rippable conditions ☒ ☐ Capistrano Formation sandstone 5.2.6 Refusal ☐ ☒ 5.2.6
Collapsible soils ☐ ☒
Expansive soils ☐ ☒
Yes
No
or
NA
Describe/ Comments Report
Section
Compressible soils ☐ ☒
DRAFT
Item: 11
1746
February 14, 2025 Page 3 of 4
Liquefaction ☐ ☒
Sinkholes ☐ ☒
Other (describe): ☐ ☒
Potential Contamination Identified
Soil ☐ ☒
Groundwater ☐ ☒
Restoration of Disturbed Areas
Backfilled with soil ☒ ☐
Borings were backfilled with soil
cuttings 1.2.2
Backfilled with grout ☐ ☒
Other (describe): ☐ ☒
Topsoil samples collected/analyzed ☐ ☒ Developed site
Corrosivity testing performed/addressed ☒ ☐
Highly corrosive potential to ferrous
metals 4.9
Culinary water quality testing performed ☐ ☒
Report
Executive summary ☒ ☐ ES-1
Wet weather construction recommendations ☐ ☒
Pad winterization/pad recommendations ☐ ☒
Frost protection recommendations ☐ ☒
Design Parameters
Fill material parameters provided
Structural fill (below foundations, slabs) ☒ ☐ 5.2.2
Site grading fill (below pavements, flatwork) ☒ ☐ 5.2.2 Select backfill (behind truck dock walls, foundations,
grade beams, etc.) ☒ ☐ 5.2.4
Trench backfill ☒ ☐ 5.2.8
Drainage fill ☐ ☒
Frost resistant fill ☐ ☒
Slab base aggregate ☒ ☐ Aggregate Base Material 4.4
Limits of debris/unsuitable removal provided ☒ ☐ 5.2.2
Over-excavation/recompaction required ☒ ☐ 5.2.2
Yes
No
or
NA
Describe/ Comments Report
Section
Depth (describe): ☒ ☐
Soils within 10 feet of the
warehouse pad should be
overexcavated to a depth of at
least 5 feet below existing grade or
3 feet below the bottom of the
footings and floor slabs, whichever
is deeper, and replaced as
structural fill.

5.2.2 Extent (include cross-section diagram) ☐ ☒
Pad subgrade stabilization required (describe): ☐ ☒ Recommendations provided 5.3 Surcharge ☐ ☒
Height (describe): ☐ ☒
Lateral extent (describe): ☐ ☒
Estimated duration (describe): ☐ ☒
Shallow Foundations ☒ ☐
psf allowable soil bearing pressure (describe): ☒ ☐ 3,000 psf 4.3.2 DRAFT
Item: 11
1747
February 14, 2025 Page 4 of 4
Deep Foundations ☒ ☐
Drilled piles for light poles and/or
Fuel Facility 4.3.3
Type (describe): ☒ ☐ Drilled piles for light poles
Options and Value Engineering Matrix provided ☐ ☒
Floor Slabs
Unreinforced (>2500 psf) ☒ ☐ 4.4
Reinforced (describe why) ☐ ☒
Subgrade modulus (ksi/in) (describe): ☒ ☐ 150 pci 4.4
Base Material thickness (min 6") (describe): ☒ ☐ 6 inches of AB 4.4 Seismic Conditions
Governing Building Code (IBC, UBC, other) ☒ ☐ 2022 CBC 4.2.1 Geologic Hazard Identified ☒ ☐ 3.4
Proximity to earthquake fault zone(s) ☒ ☐ 3.4.1
Proximity to seismic hazard zone(s) ☐ ☒
Potential for liquefaction ☐ ☒
Potential for lateral spreading ☐ ☒
Potential for seismic settlement ☐ ☒
Potential for slope stability/landslides ☐ ☒
Potential for groundshaking or geologic hazards ☐ ☒
Retaining Walls ☒ ☐ 4.7
Recommended Wall Types ☐ ☒
Recommend Kleinfelder Design ☐ ☒
Lateral earth pressure design values ☒ ☐ 4.7
Active: ☒ ☐ 4.7
At-rest: ☒ ☐ 4.7
Passive: ☒ ☐ 4.7
Seismic: ☒ ☐ 4.7
Backfill material, placement requirements ☒ ☐ 4.7
Yes
No
or
NA
Describe/ Comments Report
Section
Drainage requirements and cross-section drawing ☐ ☒
Finger Drains ☐ ☒
Required for frost ☐ ☒
Recommended for long term maintenance and
constructability ☐ ☒
Pavement
Pavement subgrade stabilization required (describe): ☐ ☒ 5.2.2 Costco asphalt mix design specified ☒ ☐ 4.8.3
Heavy and light duty pavement sections specified ☒ ☐ 4.8.2 Alternative pavement sections identified ☒ ☐ PCC pavement 4.8.4 Specification for offsite pavement sections included ☐ ☒ Data Gaps/Unknowns (describe): ☐ ☒
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TABLE OF CONTENTS
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EXECUTIVE SUMMARY ......................................................................................................ES-1 1 INTRODUCTION.............................................................................................................1

1.1 PROJECT DESCRIPTION...................................................................................1

1.2 SCOPE OF SERVICES .......................................................................................2

1.2.1 Task 1 – Background Data Review...........................................................2

1.2.2 Task 2 – Field Exploration ........................................................................2

1.2.3 Task 3 – Laboratory Testing.....................................................................3

1.2.4 Task 4 – Geotechnical Analyses ..............................................................3

1.2.5 Task 5 – Report Preparation.....................................................................3 2 SITE CONDITIONS.........................................................................................................5

2.1 SITE DESCRIPTION ...........................................................................................5 3 GEOLOGY......................................................................................................................6

3.1 GEOLOGIC SETTING .........................................................................................6

3.1.1 Site Geology.............................................................................................6

3.2 SUBSURFACE CONDITIONS .............................................................................6

3.3 GROUNDWATER................................................................................................7

3.4 ASSESSMENT OF POTENTIAL GEOLOGIC HAZARDS ....................................8

3.4.1 Localized Faulting and Seismicity.............................................................8

3.4.2 Landsliding .............................................................................................10

3.4.3 Liquefaction and Seismic Compression..................................................10

3.4.4 Expansive Soils......................................................................................11

3.4.5 Flooding .................................................................................................11

3.4.6 Oil and Gas Fields..................................................................................12

3.4.7 Land Subsidence....................................................................................12 4 GEOTECHNICAL DESIGN RECOMMENDATIONS .....................................................13

4.1 GENERAL..........................................................................................................13

4.2 SEISMIC DESIGN CONSIDERATIONS.............................................................15

4.2.1 2022 CBC Seismic Design Parameters ..................................................15

4.3 FOUNDATIONS.................................................................................................16

4.3.1 General ..................................................................................................16

4.3.2 Shallow Foundations ..............................................................................16

4.3.3 Short Drilled Pile Foundations ................................................................17

4.4 BUILDING SLAB-ON-GRADE............................................................................17

4.5 EXTERIOR FLATWORK....................................................................................18

4.6 SITE DRAINAGE...............................................................................................18

4.7 RETAINING STRUCTURES..............................................................................20

4.8 PAVEMENT SECTIONS....................................................................................21

4.8.1 Costco Pavement Design Parameters....................................................22

4.8.2 Asphalt Concrete Pavement...................................................................22

4.8.3 Asphalt Performance Grade Binder........................................................23

4.8.4 Portland Cement Concrete Pavement ....................................................23

4.8.5 Aggregate Base......................................................................................23

4.8.6 Pavement Maintenance..........................................................................24

4.9 SOIL CORROSIVITY.........................................................................................24

4.10 STORMWATER MANAGEMENT.......................................................................25 DRAFT
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5 CONSTRUCTION RECOMMENDATIONS....................................................................27

5.1 GENERAL..........................................................................................................27

5.2 EARTHWORK ...................................................................................................27

5.2.1 General ..................................................................................................27

5.2.2 Site Preparation......................................................................................27

5.2.3 Foundation Excavations .........................................................................28

5.2.4 Fill Material and Compaction Criteria......................................................29

5.2.5 Shrinkage/Bulking ..................................................................................30

5.2.6 Excavation Characteristics .....................................................................30

5.2.7 Temporary Excavations..........................................................................31

5.2.8 Trench Backfill........................................................................................31

5.3 UNSTABLE SUBGRADE CONDITIONS............................................................32

5.4 TEMPORARY SHORING...................................................................................33

5.4.1 Lateral Pressures ...................................................................................33

5.4.2 Design of Soldier Piles ...........................................................................34

5.4.3 Lagging ..................................................................................................34

5.4.4 Deflection ...............................................................................................35

5.4.5 Monitoring ..............................................................................................35

5.5 EXTERIOR FLATWORK....................................................................................35

5.6 PAVEMENTS.....................................................................................................35

5.6.1 HMA Design ...........................................................................................35

5.6.2 Construction Considerations...................................................................36 6 ADDITIONAL SERVICES .............................................................................................37

6.1 PLANS AND SPECIFICATIONS REVIEW .........................................................37

6.2 CONSTRUCTION OBSERVATION AND TESTING...........................................37 7 LIMITATIONS ...............................................................................................................38 8 REFERENCES..............................................................................................................40 TABLES
1 Summary of Significant Holocene-Active Faults Near the Project Site 2 2022 CBC Seismic Design Parameters
3 Lateral Earth Pressures for Retaining Structures (Granular Backfill) 4 Recommended Minimum Asphalt Concrete Pavement Sections 5 Corrosion Test Results
6 Summary of Infiltration Test Results
7 Structural Fill Placement And Compaction Criteria

FIGURES
1 Site Vicinity Map
2 Exploration Location Map

APPENDICES
A Field Explorations
B Laboratory Testing
C Infiltration Test Results
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EXECUTIVE SUMMARY
This report presents the results of Kleinfelder’s geotechnical study for the proposed Costco Wholesale Warehouse and Fuel Facility (CW# 24-1218) located at 26602 Towne Centre Drive in Foothill Ranch, California. The purpose of our geotechnical study was to evaluate soil and groundwater conditions at the site and provide geotechnical recommendations for project design and construction. We based our study on the Costco Wholesale Development Requirements (CWDRs), Version 2022, dated October 28, 2022.

Kleinfelder understands Costco plans to purchase an approximately 14.33-acre site to construct a new approximately 166,067-square-foot warehouse and fuel facility. The warehouse building will be a single-story, steel-framed and concrete-masonry-unit structure (30 feet in height) with rooftop parking. The fuel facility will contain three 40,000-gallon underground storage tanks (USTs), a fuel additive UST, four fueling islands, and a pre-manufactured metal canopy. The building surroundings will consist mainly of surface parking with some landscape areas. Parking and drive areas will be paved with either Portland cement concrete or asphalt concrete pavements.

Surface elevations interpreted from an ALTA survey (PBLA Surveying, Inc., 2025) provided by the design team indicates that the existing grades vary from a high of approximately 790 feet at the north portion of the site to a low of approximately 775 feet on the south portion of the site.

Preliminary grading plans and the finished floor elevation for the building slab were not available at the time of this report. Cuts and fills less than 5 feet are anticipated to achieve the desired site grades.

The proposed Costco site is located southeast of Highway 241 and Alton Parkway at 26602 Towne Centre Drive in Foothill Ranch, California, as shown on Figure 1. The site is currently developed with an existing theatre building, which will be demolished, in the southwest portion of the site surrounded by asphalt surface parking. The existing development is situated on a previously graded pad with 2:1 (horizontal to vertical) descending slopes, up to approximately 30 feet in height, on the western portion of the site.

Subsurface conditions at the site were explored by drilling 28 borings. In addition, 4 borehole infiltration tests were performed. A total of 15 borings were advanced in the building area; 9 borings and 4 infiltration tests were advanced in the parking and drive areas; and 4 borings were advanced in the proposed fuel facility location. The borings were drilled using truck-mounted, hollow-stem-auger drilling equipment to depths between approximately 21½ and 49½ feet below DRAFT
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the existing ground surface (bgs) in the warehouse building area, approximately 11½ feet bgs in the parking and drive areas; and between approximately 11½ and 26½ feet bgs in the fuel facility area. The borehole infiltration tests were drilled to depths of approximately 5 or 10 feet bgs.

The soils encountered within the borings generally consisted of artificial fill overlying sandstone of the Capistrano Formation. Artificial fill associated with previous grading at the site was observed at depths ranging from approximately 4 to 9½ feet bgs. The fill generally consisted of silty to clayey sand with varying amounts of gravel. The deepest fill was observed along the northwest side of the project site. Based on historical topographic maps, the fill may be deepest along the northwest boundary due to a northwest descending slope. Capistrano Formation sandstone was encountered below the fill to the maximum depth explored of approximately 49½ feet bgs. The sandstone was generally highly weathered and excavates as poorly to well graded sand and silty sand.

Groundwater was not encountered in our borings to the maximum depth explored of approximately 49½ feet bgs. Groundwater is not anticipated to be encountered within the depth of influence of the foundations or excavations planned for the proposed improvements.

Based on the results of our field exploration, and observations during this exploration, it is our professional opinion that the proposed project is geotechnically feasible, provided the recommendations presented in the geotechnical report are incorporated into the project design and construction. We identified the following key geotechnical considerations during our study. • The proposed Costco warehouse and fuel facility may be supported on a conventional shallow foundation system. Overexcavation and recompaction of the on-site soils is recommended in the upper fill soils within the warehouse building pad to provide relatively uniform support for the proposed warehouse and other improvements. • Light poles and the fuel facility canopy (as an alternative) may be supported on drilled pile foundations. It should be noted that drilling of the pile shafts may require heavyduty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone.
• Soils within 10 feet of the warehouse pad (including the entrance canopy, building aprons, utility pads, stairs, ramps, stoops, and the loading dock) should be overexcavated to a depth of at least 5 feet below existing grade or 3 feet below the bottom of the footings and floor slabs, whichever is deeper, and replaced as structural fill. Depending on the condition of the existing fill at the base of the excavation, DRAFT
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additional overexcavation may be required. The overexcavated soils can be moisture conditioned and recompacted as structural fill.
• For pavement, sidewalk, and flatwork areas, we recommend that the exposed subgrade be proof-rolled with heavy construction equipment (e.g. loader or smoothdrum roller) after the area has been stripped of soft earth materials and construction debris to disclose areas of soft and yielding material. Where soft and yielding material is observed, it should be overexcavated and replaced as structural fill. The proof-rolling should extend beyond the proposed improvements a horizontal distance of at least 2 feet, where possible.
• Following overexcavation and prior to replacing soils, the exposed subgrade should be proof rolled with at least a 10-ton roller, fully loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding may require additional compaction or overexcavation, as determined by Kleinfelder. Following proof rolling and any additional overexcavation, the exposed subgrade should be scarified at least 6 to 8 inches, moisture conditioned, and recompacted.
• For earthwork volume estimating purposes, an average shrinkage value of 5 to 10 percent for the upper surficial soils (generally in the upper 5 to 6 feet) may be assumed.

These values are estimates only and exclude losses due to removal of vegetation or debris. Actual shrinkage/bulking factors will depend on the types of earthmoving equipment used and should be determined during grading. We recommend that the civil engineer or the contractor contact a local earthwork contractor to confirm these values prior to finalizing any earthwork estimates.
• Foundation and slab performance depends greatly on proper irrigation and how well runoff water drains from the site. We recommend that landscape planters either not be located adjacent to structures and pavement areas or be isolated and properly drained to area drains such that cycles of wetting and drying do not impact pavements, flatwork, and other structures. Drought resistant plants and minimum watering are recommended for planters, if used. Planters should be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement. • Minimum resistivity values of the samples tested indicate that the soil may be highly corrosive to ferrous metals. The concentrations of soluble sulfates indicate that the subsurface soils represent a Class S0 Class S0 exposure to sulfate attack on concrete in contact with the soil based on ACI 318-14 Table 19.3.1.1. Therefore, in accordance with ACI Building Code 318-19, no special provisions for selection of cement type are required.

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• We have assessed the potential for storm water infiltration into the subgrade soils at the subject project site. Four borehole infiltration tests were performed at depths of approximately 5 and 10 feet bgs. Based on the results of our infiltration testing, it is our opinion that the site is not suitable for onsite infiltration. We recommend alternatives to infiltration Best Management Practices (BMPs), such as biofiltration/bio-retention systems (bio-swales and planter boxes), be implemented at the project site.

The findings, conclusions, and recommendations presented in this executive summary should not be relied upon without consulting our geotechnical report for more information. The conclusions and recommendations presented in this report are subject to the limitations presented in Section 7.

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1 INTRODUCTION
This report presents the results of Kleinfelder’s geotechnical study for the proposed Costco Wholesale Warehouse and Fuel Facility (CW# 24-1218) located at 26602 Towne Centre Drive in Foothill Ranch, California. The location of the project site is presented on Figure 1, Site Vicinity Map. The purpose of our geotechnical study was to evaluate soil and groundwater conditions at the site and provide geotechnical recommendations for project design and construction. The scope of our services was presented in our proposal titled, “Proposal for Geotechnical Study, Proposed Costco Wholesale Warehouse and Fuel Facility, 26602 Towne Centre Drive, Foothill Ranch, California, CW# 24-1218,” dated November 15, 2024. We based our study on the Costco Wholesale Development Requirements (CWDRs), Version 2022, dated October 28, 2022.

This report presents a description of the services performed, a discussion of the geotechnical conditions observed at the site, and recommendations developed from our engineering analyses of field and laboratory data. Individuals using this report should read the limitations presented in Section 7.

1.1 PROJECT DESCRIPTION
Kleinfelder understands Costco plans to purchase an approximately 14.33-acre site to construct a new approximately 166,067-square-foot warehouse and fuel facility. The warehouse building will be a single-story, steel-framed and concrete-masonry-unit structure (30 feet in height) with rooftop parking. The fuel facility will contain three 40,000-gallon underground storage tanks (USTs), a fuel additive UST, four fueling islands, and a pre-manufactured metal canopy. The building surroundings will consist mainly of surface parking with some landscape areas. Parking and drive areas will be paved with either Portland cement concrete or asphalt concrete pavements.

We understand maximum column loads will be up to approximately 250 kips for the rooftop parking, typical wall loads will be approximately 4.5 kips per lineal foot, canopy column loads will be approximately 50 kips, and the total slab load (dead plus live loads) will be approximately 500 psf.

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Preliminary grading plans and the finished floor elevation for the building slab were not available at the time of this report. Cuts and fills less than 5 feet are anticipated to achieve the desired site grades.

1.2 SCOPE OF SERVICES
The scope of our geotechnical study consisted of a literature review, subsurface explorations, geotechnical laboratory testing, engineering evaluation and analysis, and preparation of this report. Studies to assess environmental hazards that may affect the soil and groundwater at the site were beyond our geotechnical scope of services. The following paragraphs present a description of our services.

1.2.1 Task 1 – Background Data Review
We reviewed readily available published and unpublished geologic literature in our files and the files of public agencies, including selected publications prepared by the California Geological Survey and the U.S. Geological Survey. We also reviewed readily available seismic and faulting information, including data for designated earthquake fault zones and our in-house database of faulting in the general site vicinity.

1.2.2 Task 2 – Field Exploration
Because the site is developed, our field exploration could not be performed in full accordance with the CWDRs (i.e. could not perform test pits or any field exploration in areas of existing buildings).

Subsurface conditions at the site were explored by drilling 28 borings. In addition, 4 borehole infiltration tests were performed. A total of 15 borings were advanced in the building area; 9 borings and 4 infiltration tests were advanced in the parking and drive areas; and 4 borings were advanced in the proposed fuel facility location. The borings were drilled using truck-mounted, hollow-stem-auger drilling equipment to depths between approximately 21½ and 49½ feet below the existing ground surface (bgs) in the warehouse building area, approximately 11½ feet bgs in the parking and drive areas; and between approximately 11½ and 26½ feet bgs in the fuel facility area. The borehole infiltration tests were drilled to depths of approximately 5 or 10 feet bgs. The approximate locations of the borings and infiltration tests are presented on Figure 2, Exploration Location Map.

Prior to commencement of the fieldwork, Underground Service Alert (USA) was notified and various geophysical techniques were used at the boring locations to identify potential conflicts with subsurface structures. A Kleinfelder staff professional supervised the field operations and DRAFT
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logged the explorations. Selected bulk and drive samples were retrieved, placed in plastic bags, or sealed in sample tubes, and transported to our laboratory for further evaluation. The number of blows necessary to drive a Standard Penetration Test (SPT) sampler or California-type sampler was recorded. Soil descriptions used on the logs result from field observations and data, as well as from laboratory test data. Stratification lines on the logs represent the approximate boundary between soil and/or rock types, and the actual transition may vary and can be gradual. Appendix A presents a description of the field exploration program, exploration logs, and a legend of terms and symbols used on the logs.

1.2.3 Task 3 – Laboratory Testing
Laboratory testing was performed on representative bulk and relatively undisturbed samples to assist in soil classification and development of engineering parameters for geotechnical design.

Laboratory testing consisted of moisture content, dry unit weight, wash sieve (percent passing No. 200 sieve), sieve & hydrometer analysis, direct shear, Modified Proctor, R-value, and preliminary corrosion testing. Laboratory testing was performed by both Kleinfelder and AP Engineering and Testing, Inc. of Pomona, California. Appendix B presents the results of the laboratory testing performed for this study.

1.2.4 Task 4 – Geotechnical Analyses
We analyzed field and laboratory data relative to the anticipated finished grades, warehouse layout, and structural loads to provide geotechnical recommendations for design and construction.

We evaluated feasible foundation systems, concrete slab support, pavement design, and earthwork. Seismic design parameters in accordance with the 2022 California Building Code (CBC) are also presented.

1.2.5 Task 5 – Report Preparation
This report summarizes the services performed, data acquired, and our findings, conclusions, and geotechnical recommendations for the design and construction of the proposed improvements.

Our report includes the following items:
• Vicinity map (Figure 1) and field exploration location map (Figure 2) showing the approximate boring and infiltration test locations.
• Boring and infiltration test logs (Appendix A).
• Results of laboratory testing (Appendix B).

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• Results of infiltration tests (Appendix C).
• Discussion of general site conditions.
• Discussion of general subsurface conditions as encountered during our field exploration. • Discussion of regional and local geology.
• Recommendations for seismic design parameters in accordance with the 2022 CBC. • Recommendations for foundation design, allowable bearing pressures, embedment depths, and compatibility constraints under various loading conditions. • Anticipated total and differential static settlements. • Recommendations for site preparation, earthwork, temporary slope inclinations, fill placement, and compaction specifications, including the excavation characteristics of subsurface soil deposits and formational materials.
• Recommendations for support of floor slabs and slabs-on-grade. • Recommendations for flexible and rigid pavement structural sections for light- and heavy-duty pavement based on Equivalent Single Axle loading presented in the CWDRs. • Recommendations for design of retaining structures, including active and at-rest lateral earth pressures, passive and frictional resistance, and applicable surcharge loads. • Preliminary evaluation of the corrosion potential of the on-site soils.

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2 SITE CONDITIONS

2.1 SITE DESCRIPTION
The proposed Costco site is located southeast of Highway 241 and Alton Parkway at 26602 Towne Centre Drive in Foothill Ranch, California, as shown on Figure 1. The site is currently developed with an existing theatre building, which will be demolished, in the southwest portion of the site surrounded by asphalt surface parking. The existing development is situated on a previously graded pad with 2:1 (horizontal to vertical) descending slopes, up to approximately 30 feet in height, on the western portion of the site.

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3 GEOLOGY

3.1 GEOLOGIC SETTING
The project site is located in the northern Peninsular Ranges geomorphic province, a province known for its northwest trending valleys and ranges that are subparallel to the San Andreas and related faults (California Geological Survey (CGS), 2002). More specifically the project site lies along the western flanks of the Santa Ana Mountains. The Santa Ana Mountains are composed of a basement complex of middle Mesozoic-age crystalline and semi-crystalline rocks unconformably overlain by late Cretaceous and Cenozoic clastic strata (Schoellhamer et al., 1981) that were uplifted and folded as a result of movement along the Elsinore Fault and Whittier Fault (Morton and Miller, 2006). The site is bounded by southwest-trending canyons and washes that emerge from the western flanks and deposit young alluvial deposits overlying tertiary-aged strata.

3.1.1 Site Geology
The project site is located in the foothills of the Santa Ana Mountains between Borrego Canyon Wash to the northwest and Serrano Creek to the southeast. Between these drainage areas, the Oso member of the tertiary-aged Capistrano Formation is mapped at the ground surface (Morton and Miller, 2006). Quaternary-aged slope wash (Qsw) is mapped along the perimeter of these exposures and Quaternary-aged alluvium (Qal) overlies the Capistrano Formation in the drainage areas. At the site, the Oso Member of the Capistrano Formation, a white to light gray, massive, fine to coarse grained marine sandstone with scattered gravel underlies up to 9½ feet of artificial fill. According to a historical topographic map from 1949 (U.S. Geological Survey, Department of the Interior, 1949), the ground surface elevation across the site originally exceeded ~790 feet, with the exception of the northwest boundary where the ground surface descended to a local drainage at an elevation of 720 to 740 feet, parallel to the site boundary.

Descriptions of the soils encountered in Kleinfelder’s subsurface exploration are presented in the following sections and on the boring logs presented in Appendix A.

3.2 SUBSURFACE CONDITIONS
The soils encountered within the borings generally consisted of artificial fill overlying sandstone of the Capistrano Formation. Artificial fill associated with previous grading at the site was observed at depths ranging from approximately 4 to 9½ feet bgs. The fill generally consisted of DRAFT
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silty to clayey sand with varying amounts of gravel. The deepest fill was observed along the northwest side of the project site. Based on historical topographic maps, the fill may be deepest along the northwest boundary due to a northwest descending slope. Capistrano Formation sandstone was encountered below the fill to the maximum depth explored of approximately 49½ feet bgs. The sandstone was generally highly weathered and excavates as poorly to well graded sand and silty sand.

3.3 GROUNDWATER
Groundwater was not encountered in our borings to the maximum depth explored of approximately 49½ feet bgs. The project site is located within the Southeast Management Area of the Coastal Plain of Orange County Groundwater Basin (Basin 8-1) (OCWD, City of La Habra and IRWD, 2022). This area consists of several small areas southeast of the Orange County Water District Management Area, a portion of which falls within the Irvine Ranch Water District (IRWD) service area. As reported by IRWD, depth to groundwater information is limited to a half dozen production wells, of which only one is active (LF-2). The nearest IRWD well is LF-7, located approximately 1,500 feet to the southwest of the site at an approximate elevation of 832 feet, and showed groundwater at a depth of approximately160 feet below ground surface (El. 672) between 2020 and 2021. Based on a 2024 groundwater report (Montrose Environmental, 2025) for a former Palisades Gas and Wash Station #824 near Portola Parkway and Market Place, depth to groundwater is within approximately 10 to 15 feet of the ground surface (approximate El 802 to 792). Depth to groundwater here may reflect that site’s proximity to local drainages (Borrego Canyon, Serrano Creek) and their tributaries. Based on available groundwater information in the site vicinity and at the site, groundwater is likely to be encountered within approximately 50 to 100 feet of the ground surface. The California Geological Survey does not report a historical high depth to groundwater at the site but reports historical high groundwater of up to 10 feet below ground surface in nearby drainage areas (Pridmore, C.L, 2000).

Groundwater is not anticipated to be encountered within the depth of influence of the foundations or excavations planned for the proposed improvements, however localized zones of perched water, increased soil moisture content and fluctuations of the groundwater level, should be anticipated during and following the rainy season. Irrigation of landscaped areas on or adjacent to the site can also cause a fluctuation of local groundwater levels.

3.4 ASSESSMENT OF POTENTIAL GEOLOGIC HAZARDS

3.4.1 Localized Faulting and Seismicity
The most significant geologic hazard to the project site is considered to be the potential for moderate to strong seismic shaking that is likely to occur during the design life of the project. The project site is located in the highly seismic southern California region within the influence of several fault systems. Based on CGS Special Publication 42 (CGS, 2018) the site is not located within a State-designated Alquist-Priolo (AP) Earthquake Fault Zone (EFZ). The nearest mapped Earthquake Fault Zone is located approximately 11.4 miles northeast of the site along the Glen Ivy Segment of the Elsinore fault (CGS, 2018).

The CGS defines Holocene-active faults as those demonstrated to have displacement of the Holocene-age ground surface within the past 11,700 years (end of the Holocene geologic era) and are believed to pose the risk of ground rupture. Pre-Holocene faults that have been demonstrated to have no Holocene surface displacement are not regulated for fault hazards under the CGS Earthquake Zoning Act. Faults of undetermined age cannot be classified as Holoceneactive or pre-Holocene active because there is insufficient data to demonstrate activity with respect to the Holocene time period. Active faults without surface expression (buried faults) and other potentially active seismic sources which may be capable of generating earthquakes are not currently zoned by the Act, but they are known to be present in the region (e.g. San Joaquin fault).

The Elsinore fault is a right-lateral strike slip fault, that is approximately 185 miles long. The Glen Ivy (fault) segment of the Elsinore Fault, is the segment of the fault nearest to the project site, is approximately 22 miles long (Cao et al., 2003) and is found between Corona and Lake Elsinore.

The estimated slip rate along the Glen Ivy fault is approximately 5 millimeters/year (Dawson and Weldon, 2013). The surface trace of the Elsinore fault has been mapped by the State and designated as an EFZ (CGS, 2003). The surface trace has been mapped approximately 11.4 miles northeast of the project site and the active fault is capable of generating an earthquake of Mw 6.8 (Cao et al., 2003) that could lead to significant ground shaking at the site.

The San Joaquin Hills Blind Thrust Fault is a southwest-dipping (approximately 23 degrees), lowangle reverse (thrust) fault that is concealed (blind) and does not reach the ground surface. Since it is not exposed at the ground surface and does not present a potential for surface fault rupture it is not zoned under the Alquist-Priolo Act as an EFZ. Its trace, at depth, is approximately 4.2 miles southwest of the project site and is an important fault with respect to geologic hazards.

Researchers (Grant et al.,1999 and 2002) hypothesize that local compression caused by a bend DRAFT
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in the Newport-Inglewood-Rose Canyon Fault Zone results in uplift of the San Joaquin Hills along the San Joaquin Hills Blind Thrust Fault. Uplift along this fault began in the early Pleistocene and has continued to the present. This fault has a slip rate of 0.2 to 1.0 millimeters/year (Dawson and Weldon, 2013) and is capable of generating a magnitude (Mw) 7.1 earthquake (Petersen et al., 2008). An earthquake occurring along this fault is expected to cause significant ground shaking at the site.

There are several faults within Southern California that are capable of producing large earthquakes. Four major northwest-trending faults divide the Peninsular Ranges province into blocks (Newport-Inglewood-Rose Canyon, Elsinore, San Jacinto and San Andreas). Table 1 below provides the nearest distance to each fault and a listing of some of the seismic parameters (i.e., fault type, slip rate and magnitude) associated with each of the faults.

Table 1
Summary Of Significant Holocene-Active Faults Near the Project Site Fault Name
(segment name)
Approximate
Fault Distance and
Direction from Site
(miles)
Fault Type
Slip
Rate/Year
(mm)
Maximum
Magnitude
(Mmax)
San Joaquin Hills thrust 4.2, southwest Reverse 0.6 7.1 Elsinore (Glen Ivy Fault) 11.4, northeast Right lateral 5 6.9 Elsinore
(all segments combined) 11.4, northeast Right lateral 4.4 7.8 Newport-Inglewood
(Los Angeles Basin) 16.7, west southwest Right lateral strike slip 1 7.1 Newport-Inglewood
Connected alt 1
(all segments combined)

16.7, west southwest Right lateral 1 7.5
San Jacinto
(San Bernardino) 33.9, northeast Right lateral 6 7.1
San Andreas (San
Bernardino Mountains 41.0, northeast Right lateral 19 7.2 Southern San Andreas
(all segments combined) 41.0, northeast Right lateral 34 8.2 Sources:

Dawson, T.E., and R.J. Weldon. 2013. Appendix B – Geologic Slip Rate Data and Geologic Deformation Model in Field, et al., 2013.

Uniform California earthquake rupture forecast, version 3 (UCERF3)—The time-independent model: U.S. Geological Survey (USGS) Open-File Report 2013–1165, and California Geological Survey (CGS) Special Report 228.

All Other data - Petersen, M.D., Frankel, A.D., Harmsen, S.C., Mueller, C.S., Haller, K., Wheeler, R.L., Wesson, R.L., Zeng, Y., Boyd, O.S., Perkins, D.M., Luco, N., Field, E.H., Wills, C.J., and Rukstales, K.S., 2008, Documentation for the 2008 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey (USGS), Open-File Report 2008–1128, 61p.

3.4.2 Landsliding
A landslide results from the downgradient movement of earth material along a slope or hillside.

Landslides occur on slopes when soil and base material lose strength, typically from an increase in pore-water pressures and the forces of gravity, causes the soil and base material to move down-gradient. Landslides can result from a variety or combination of root causes such as steepness of slope, type of material, water content of slope soils, amount and type of vegetation, and major natural hazards such as earthquakes, volcanic eruptions, wildfires, and floods. Steeper slopes and weaker rocks are the most vulnerable to mass wasting events. Landslides can occur as slow but progressive movements of soil over time or from the rapid deterioration of soil on a slope. They are frequently triggered by intense rainfall or seismic shaking.

A portion of the site is located within State-designated Seismic Hazard Zone for Earthquake Induced-Landslides (CGS, 2001). The California Geological Survey and California Department of Conservation Landslide Inventory (beta) online database (2025) shows the same landslide and describes it as a dormant mature/old/relict rock slide that had failed from near to the northwest.

More specifically, the landslide failed from the northwest boundary of the site into a small tributary to Borrego Canyon Wash. According to historical photographs, grading of the site as early as 1994 levelled the site. No evidence of the landslide remains. No evidence of distress was observed at the time of our investigation. The risk from landslides and other forms of mass wasting is considered low due and lack of significant slopes at the site.

3.4.3 Liquefaction and Seismic Compression
The term liquefaction describes a phenomenon in which saturated, cohesionless soils temporarily lose shear strength (liquefy) due to increased pore water pressures induced by strong, cyclic ground motions during an earthquake. Structures founded on or above potentially liquefiable soils may experience bearing capacity failures due to the temporary loss of foundation support, vertical settlements (both total and differential), and/or undergo lateral spreading. The factors known to influence liquefaction potential include soil type, relative density, grain size, confining pressure, depth to groundwater, and the intensity and duration of the seismic ground shaking. Liquefaction is most prevalent in loose to medium dense, silty, sandy, and gravelly soils below the groundwater table.

The site is not located within a State hazard zone for liquefaction (CGS, 2001). Because of the lack of groundwater and the soil types at the site, the potential for liquefaction is not considered a hazard at the site.

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Seismic compression results from the accumulation of contractive volumetric strains in unsaturated soil during earthquake shaking. Loose to medium dense granular material with no fines or with low plasticity fines are most susceptible to seismic compression. Based on the density and soil composition of the underlying soils, the potential for seismic compression (dynamic dry settlement) is considered to be very low.

3.4.4 Expansive Soils
Expansive soils are characterized by their ability to undergo significant volume changes (shrink or swell) due to variations in moisture content. Changes in soil moisture content can result from precipitation, landscape irrigation, utility leakage, roof drainage, perched groundwater, drought, or other factors, and may result in unacceptable settlement or heave of structures or concrete slabs supported on grade. The surficial soils are generally silty to clayey sands overlying sandstone. The expansion potential of the near surface soils is considered low.

3.4.5 Flooding
Flooding occurs as a result of several factors in developed areas. These factors are rainfall rates that exceed an area’s ability to absorb or control the runoff, impounded water retained behind a downstream flood control structure (upstream-inundation), failure of an upstream flood control structure (inundation), and tsunami.

The Flood Insurance Rate Map (FEMA, 2019) prepared by the Federal Emergency Management Agency (FEMA) was reviewed to identify the potential flood hazard for the project. This map indicates the site is within Zone X which is defined as being an area determined to be outside the

0.2-percent-annual-chance-flood. Based on this information, the potential for the project site to be impacted by regional flooding is considered low.

Dam inundation occurs when a dam is breached or there is an uncontrolled release of water that may cause flooding downstream. According to the Division of Safety of Dams online database (Division of Safety of Dams, 2025), the project site is not located within a hazard zone for dam inundation.

The site within not located within a tsunami hazard area and the risk of tsunami inundation is considered low (State of California, 2021). Due to the location of the site inland of sea, elevation of the site, and the State of California’s hazard classification outside the area of tsunami hazard, the hazard due to tsunami is considered very low.

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A seiche is a wave or sloshing of a body of water that is at least partially impounded caused by strong wind or seismic shaking. The site is not located near a body of water capable of generating a seiche during a seismic event.

3.4.6 Oil and Gas Fields
The project site is not located within a mapped petroleum producing field of Southern California and no oil/gas wells are reported within the Project Site (California Department of Conservation, California Geologic Energy Management Division (CalGEM), 2025). Based on information available from CalGEM, three (3) idle oil and gas wells are within approximately 2.5 to 4.5 miles of the site and several plugged core holes and plugged dry holes are within 1.5 to 2.5 miles of the site. Additional undocumented well(s) may be present and buried near the site.

3.4.7 Land Subsidence
Ground subsidence is a gradual settling or sudden sinking of the earth's surface owing to subsurface movement of earth materials. Ground subsidence results from fluid (water or petroleum) extraction from underlying sediments and/or formations, which causes the collapse of pore spaces previously occupied by the removed fluid. The collapse of these pore spaces compacts the underlying formations leading to a gradual drop in ground surface elevation. Ground subsidence is most often found in areas where large volumetric withdrawals of fluids from underground reservoirs has occurred or is ongoing. Ground shaking from tectonic activity can exacerbate the vertical sinking of land in an area over the withdrawal site. Structures and improvements located in subsidence-prone areas are at risk for damage if subsidence were to occur.

The USGS has been tracking subsidence in California since the early 20th century and has developed maps that illustrate areas of recorded subsidence across the state (USGS, 2021). Most of the subsidence has resulted from excessive groundwater pumping for municipal, industrial, and agricultural uses, although oil extraction is also a documented cause. A review of the USGS subsidence interactive online map shows the project site is not documented to be experiencing subsidence.

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4 GEOTECHNICAL DESIGN RECOMMENDATIONS

4.1 GENERAL
Based on the results of our field exploration, laboratory testing, and engineering analyses conducted during this study, it is our professional opinion the proposed project is geotechnically feasible, provided the design and construction recommendations presented in this report are incorporated into the project. We identified the following key geotechnical considerations during our study.
• The proposed Costco warehouse and fuel facility may be supported on a conventional shallow foundation system. Overexcavation and recompaction of the on-site soils is recommended in the upper fill soils within the warehouse building pad to provide relatively uniform support for the proposed warehouse and other improvements. • Light poles and the fuel facility canopy (as an alternative) may be supported on drilled pile foundations. It should be noted that drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone.
• Soils within 10 feet of the warehouse pad (including the entrance canopy, building aprons, utility pads, stairs, ramps, stoops, and the loading dock) should be overexcavated to a depth of at least 5 feet below existing grade or 3 feet below the bottom of the footings and floor slabs, whichever is deeper, and replaced as structural fill. Depending on the condition of the existing fill at the base of the excavation, additional overexcavation may be required.

The overexcavated soils can be moisture conditioned and recompacted as structural fill. • For pavement, sidewalk, and flatwork areas, we recommend that the exposed subgrade be proof-rolled with heavy construction equipment (e.g. loader or smooth-drum roller) after the area has been stripped of soft earth materials and construction debris to disclose areas of soft and yielding material. Where soft and yielding material is observed, it should be overexcavated and replaced as structural fill. The proof-rolling should extend beyond the proposed improvements a horizontal distance of at least 2 feet, where possible. • Following overexcavation and prior to replacing soils, the exposed subgrade should be proof rolled with at least a 10-ton roller, fully loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding may require additional compaction or overexcavation, as determined by Kleinfelder. Following proof rolling and any additional DRAFT
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overexcavation, the exposed subgrade should be scarified at least 6 to 8 inches, moisture conditioned, and recompacted.
• For earthwork volume estimating purposes, an average shrinkage value of 5 to 10 percent for the upper fill soils (generally in the upper 5 to 6 feet) may be assumed. These values are estimates only and exclude losses due to removal of vegetation or debris. Actual shrinkage/bulking factors will depend on the types of earthmoving equipment used and should be determined during grading. We recommend that the civil engineer or the contractor contact a local earthwork contractor to confirm these values prior to finalizing any earthwork estimates.
• Foundation and slab performance depends greatly on proper irrigation and how well runoff water drains from the site. We recommend that landscape planters either not be located adjacent to structures and pavement areas or be isolated and properly drained to area drains such that cycles of wetting and drying do not impact pavements, flatwork, and other structures. Drought resistant plants and minimum watering are recommended for planters, if used. Planters should be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement.
• Minimum resistivity values of the samples tested indicate that the soil may be highly corrosive to ferrous metals. The concentrations of soluble sulfates indicate that the subsurface soils represent a Class S0 Class S0 exposure to sulfate attack on concrete in contact with the soil based on ACI 318-14 Table 19.3.1.1. Therefore, in accordance with ACI Building Code 318-19, no special provisions for selection of cement type are required. • We have assessed the potential for storm water infiltration into the subgrade soils at the subject project site. Four borehole infiltration tests were performed at depths of approximately 5 and 10 feet bgs. Based on the results of our infiltration testing, it is our opinion that the site is not suitable for onsite infiltration. We recommend alternatives to infiltration Best Management Practices (BMPs), such as bio-filtration/bio-retention systems (bio-swales and planter boxes), be implemented at the project site.

The following opinions, conclusions, and recommendations are based on the properties of the materials encountered in the borings and test pits, the results of the laboratory-testing program, and our engineering analyses performed, and should be incorporated into project design and construction.

4.2 SEISMIC DESIGN CONSIDERATIONS

4.2.1 2022 CBC Seismic Design Parameters
Based on information obtained from the investigation, published geologic literature and maps, and on our interpretation of the ASCE/SEI 7-16 criteria, it is our opinion that the project site may be classified as Site Class C, Very Dense Soil/Soft Rock. Approximate coordinates for the site are noted below.
• Latitude: 33.6773 °N
• Longitude: 117.6684 °W
The Risk-Targeted Maximum Considered Earthquake (MCER) mapped spectral accelerations for

0.2 seconds and 1 second periods (Ss and S1) were estimated using the OSHPD seismic design maps web-based application (available at https://seismicmaps.org/). The mapped acceleration values and associated soil amplification factors (Fa and Fv) based on the 2022 CBC (non site-specific) and corresponding site modified spectral accelerations (SMS and SM1) and design spectral accelerations (SDS and SD1) are presented in Table 2.

Table 2
2022 CBC Seismic Design Parameters

DESIGN PARAMETER RECOMMENDED VALUE
Site Class C
Ss (g) 1.289
S1 (g) 0.458
Fa 1.2
Fv 1.5
SMS (g) 1.546
SM1 (g) 0.687
SDS (g) 1.031
SD1 (g) 0.458
PGAM (g) 0.640
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4.3 FOUNDATIONS

4.3.1 General
Based on the results of our field exploration, laboratory testing, and geotechnical analyses, the proposed warehouse building and fuel facility may be supported on conventional shallow spread footing foundations founded on subgrade prepared in accordance with Section 5.2.2. Light poles and the fuel facility canopy (as an alternative) may be supported on drilled pile foundations. It should be noted that drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone.

Recommendations for the design and construction of shallow foundations and short drilled pile foundations are presented below.

4.3.2 Shallow Foundations
Allowable Soil Bearing Pressure
Footings may be designed for a net allowable soil bearing pressure of 3,000 pounds per square foot (psf) for dead plus sustained live loads. Footings should be embedded at least 18 inches below the lowest adjacent exterior grade. The footing dimension and reinforcement should be designed by the structural engineer; however, continuous and isolated spread footings should have minimum widths of 18 and 24 inches, respectively. A one-third increase in the above bearing pressure can be used for transient wind or seismic loads.

Estimated Settlements
We estimate total static settlement of foundations designed and constructed in accordance with the recommendations presented above to be less than 1 inch. Differential static settlement between similarly loaded footings is estimated to be less than ½ inch over 50 feet.

Lateral Resistance
Lateral load resistance may be derived from passive resistance along the vertical sides of the footings, friction acting at the base of the footing, or a combination of the two. An allowable passive resistance of 250 psf per foot of depth may be used for design. Allowable passive resistance values should not exceed 2,500 psf. An allowable coefficient of friction of 0.35 between the base of the footings and the engineered fill soils can be used for sliding resistance using the dead load normal stresses. Friction and passive resistance may be combined without reduction. We recommend that DRAFT
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the first foot of soil cover be neglected in the passive resistance calculations if the ground surface is not protected from erosion or disturbance by a slab, pavement, or in a similar manner.

4.3.3 Short Drilled Pile Foundations
Axial Capacity
The compressive axial capacity of drilled piles may be estimated based on an allowable skin friction capacity of 200 pounds per square foot. The upper one foot of the skin friction capacity should be ignored. The uplift capacity may be estimated as 70 percent of the allowable compressive axial capacity. A one-third increase in the allowable capacities may be used for transient loading conditions such as wind or seismic loads.

Settlement
Settlement of the proposed canopy supported on drilled piles, as recommended, is estimated to be less than ½ inch. This value does not include elastic compression of the piers under design loads.

Lateral Resistance
The drilled pile foundations lateral resistance can be designed in general accordance with Section 1807.3 of the CBC. We recommend a lateral soil bearing pressure of 250 psf per foot of depth below grade. The lateral soil bearing pressure should not exceed 2,500 psf. Since drilled piles will act as isolated pole foundations, the allowable lateral soil bearing pressure may be increased by a factor of two for short-term lateral loads provided the structure will not be adversely affected by ½ inch of lateral movement at the ground surface.

4.4 BUILDING SLAB-ON-GRADE
Concrete slab-on-grade floors are appropriate for the proposed warehouse, provided subgrade is prepared in accordance with Section 5.2.2. In accordance with the CWDRs, we recommend the slab be a minimum nominal thickness of 6.0 inches and underlain by at least 6.0 inches of aggregate base material. Aggregate base materials should meet current Caltrans specifications for Class 2 aggregate base. Please note that Caltrans Class 2 aggregate base may utilize recycled materials. Costco typically does not allow the use of recycled materials within the building pad. Alternatively, the aggregate base course could meet the specifications for Crushed Aggregate Base (CAB) as defined in Section 200-2 of the current edition of the Standard Specifications for Public Works Construction (Greenbook).

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A modulus of subgrade reaction of 150 pounds per cubic inch may be used for design of slabs underlain by 6.0 inches of aggregate base material. Pursuant to current Costco Wholesale standard construction design practices, we have evaluated whether steel reinforcement is needed in the floor slab. Based on the geotechnical characteristics of the site, the proposed warehouse can be built with a non-reinforced slab.

Floor slab control joints should be used to reduce damage due to shrinkage cracking. Control joint spacing is a function of slab thickness, aggregate size, slump and curing conditions. The requirements for concrete slab thickness, joint spacing, and reinforcement should be established by the designer, based on experience, recognized design guidelines and the intended slab use.

Placement and curing conditions will have a strong impact on the final concrete slab integrity.

Kleinfelder typically recommends installation of a vapor barrier beneath the slab to mitigate potential moisture issues such as flooring performance and mold. However, we understand that Costco Wholesale has determined that moisture barriers are not to be used in construction of Costco Wholesale warehouses due to adverse effects on concrete curing and performance.

Therefore, we have provided construction recommendations that do not include installation of a moisture barrier, with the understanding that there will be an increased risk for adverse moisture issues.

4.5 EXTERIOR FLATWORK
Prior to casting exterior flatwork, the subgrade soils should be scarified, moisture conditioned, and recompacted or overexcavated, as recommended in Section 5.2.2. Exterior concrete slabs for pedestrian traffic or landscape outside of the building pad limits should be at least four inches thick. Weakened plane joints in sidewalks should be located at intervals of about 6 feet. Careful control of the water/cement ratio should be performed to avoid shrinkage cracking due to excess water or poor concrete finishing or curing. Unreinforced slabs should not be built in areas where further saturation may occur following construction.

4.6 SITE DRAINAGE
Foundation and slab performance depends greatly on proper irrigation and how well runoff water drains from the site. This drainage should be maintained both during construction and over the entire life of the project. The ground surface around structures should be graded such that water drains away from structures without ponding. The surface gradient needed to do this depends on the landscaping type. Surface gradients should conform to current Costco Wholesale standards and the CBC.

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We recommend that landscape planters either not be located adjacent to structures and pavement areas or be isolated and properly drained to area drains such that cycles of wetting and drying do not impact pavements, flatwork, and other structures. Drought resistant plants and minimum watering are recommended for planters, if used. No planters should be installed immediately adjacent to structures unless they are water-proofed and have a drainpipe connected to an area drain outlet. Planters should be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement.

Due to poor draining subgrade conditions, we recommend drainage inlets and catch basins include pavement underdrains as shown in Detail 16_16 of the CWDRs. Drains should be designed and constructed per Costco’s standard details and laterals should extend at least 10 feet from the catch basins. Perimeter foundation drains are not necessary.

Where slabs or pavement areas abut landscaped areas, the aggregate base and subgrade soil should be protected against saturation. Vertical cut off structures are recommended to reduce lateral seepage under slabs from adjacent landscaped areas. Vertical cut-off structures may consist of deepened concrete perimeters, or equivalent, extending at least three inches below the base/subgrade interface. Vertical cut-off structures should be poured neat against undisturbed native soil or compacted fill. The cut-off structures should be continuous.

Operations personnel should be instructed to limit irrigation to the minimum level necessary to properly sustain landscaping plants. Should excessive irrigation, waterline breaks or unusually high rainfall occur, saturated zones and “perched” groundwater may develop, which could soften subgrade and reduce pavement life, and could also create potholes. We also recommend that the downspouts from roof drains be connected to a designed subsurface drainage system such as a storm sewer, etc. to avoid discharging water onto pavement areas and backfill zones around the warehouse.

Potential sources of water such as water pipes, drains, and the like should be frequently examined for signs of leakage or damage. Any such leakage or damage should be promptly repaired. Sewer lines beneath the warehouse should have a sufficient slope (at least 1 percent). Plumbing and utility lines should be provided with flexible joints or oversized sleeves where they penetrate floor slabs to prevent breakage caused by differential slab movement. In addition, utility trenches should be plugged with cohesive backfill where they enter the building to reduce moisture infiltration along pipe bedding material. The cohesive backfill materials should have a plasticity index (PI) between 15 and 30 and no less than 70 percent of the particles passing the No. 200 sieve.

4.7 RETAINING STRUCTURES
Design earth pressures for retaining structures depend primarily on the allowable wall movement, wall inclination, type of backfill materials, backfill slopes, surcharges, and drainage. The earth pressures provided assume that granular (sandy) soils will used as backfill. The on-site clayey soils should not be used as retaining wall backfill. Granular backfill, which should meet the requirements for imported fill as defined in Section 5.2.4, should extend behind walls a horizontal distance of at least one-half the height of the wall (a gravel backdrain may be included in this zone). Determination of whether the active or at-rest condition is appropriate for design will depend on the flexibility of the walls. Walls that are free to rotate at least 0.002 radians (deflection at the top of the wall of at least 0.002 x H, where H is the unbalanced wall height) may be designed for the active condition. Walls that are not capable of this movement should be assumed rigid and designed for the at-rest condition. The recommended active and at-rest earth pressures and passive resistance values are provided in Table 3.

Table 3
Lateral Earth Pressures For Retaining Structures
(Granular Backfill)
Wall Movement Backfill Condition Equivalent Fluid
Pressure (pcf)
Seismic Increment
(pcf)
Free to Deflect
(active condition) Level
40 18*
Restrained
(at-rest condition) 60 N/A**
Note: * Walls supporting more than 6 feet of backfill should be designed to support an incremental seismic lateral pressure, which is applied as a triangular pressure distribution with a maximum pressure at the bottom of the wall, applied similar to the active lateral earth pressure. ** for restrained walls, use the static active earth pressure plus the seismic increment to check the seismic condition; use at-rest earth pressure only to check the static condition; the larger loading of both cases should be used for the design of restrained wall.

The above lateral earth pressures do not include the effects of surcharges (e.g., traffic, footings), compaction, or truck-induced wall pressures. Any surcharge (live, including traffic, or dead load) located within a 1:1 (horizontal to vertical) plane drawn upward from the base of the excavation should be added to the lateral earth pressures. The lateral contribution of a uniform surcharge load located immediately behind walls may be calculated by multiplying the surcharge by 0.33 for cantilevered walls under active conditions and 0.50 for restrained walls under at-rest conditions.

Walls adjacent to areas subject to vehicular traffic should be designed for a 2-foot equivalent soil surcharge (250 psf). Lateral load contributions from other surcharges located behind walls may be provided once the load configurations and layouts are known.

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Walls should be properly drained or designed to resist hydrostatic pressures. Adequate drainage is essential to provide a free-drained backfill condition so that there is no hydrostatic buildup behind the wall. Walls should also be appropriately waterproofed to reduce the potential for staining. Drainage behind loading dock walls can consist of weep holes placed along the base of the wall. Weep holes should be spaced 10 to 15 feet apart and connected with a gravel drain consisting of approximately 2 cubic feet of clean gravel per foot of wall length wrapped with filter fabric. Drains should be provided within the loading dock areas to collect both surface water and any seepage from the weep holes. Other types of retaining walls should have a continuous back drain as described below.

For backfill of walls with a continuous back drain, except for the upper 2 feet, the backfill immediately behind retaining walls (minimum horizontal distance of 2 feet measured perpendicular to the wall) should consist of free-draining ¾-inch crushed rock wrapped with filter fabric. The upper 2 feet of cover backfill should consist of relatively impervious material. A 4-inch-diameter perforated PVC pipe, placed perforations down at the bottom of the rock layer leading to a suitable gravity outlet, should be installed at the base of the walls.

As an alternative to the gravel drain noted above, a manufactured drain panel may be utilized behind retaining walls in addition to normal waterproofing. This system generally consists of a prefabricated drain panel lined with filter fabric. At the wall base, we recommend that a gravel drain be installed to collect and discharge drainage to a suitable outlet. The drain should consist of a 4-inch-diameter perforated PVC pipe, placed perforations down at the bottom of approximately 2 cubic feet of clean gravel per foot of wall length. The gravel drain should be wrapped in filter fabric (Mirafi 140N or equivalent). The pipe should be sloped to drain to a suitable outlet and cleanouts should be provided at appropriate intervals.

If drainage behind the wall is omitted, the wall should be designed for full hydrostatic pressure.

The design of any drain system should be submitted to Kleinfelder for review to check that our recommendations have been properly incorporated into the design. Installation of the drainage system should be reviewed and documented by a Kleinfelder representative.

4.8 PAVEMENT SECTIONS
The required pavement structural sections will depend on the expected wheel loads, volume of traffic, and subgrade soils. We have provided asphalt concrete pavement sections for traffic indices provided in the CWDRs (Costco, 2022). Positive drainage of the paved areas should be provided since moisture infiltration into the subgrade may decrease the life of pavements. Curbing DRAFT
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located adjacent to paved areas should be founded in the subgrade, not the aggregate base, in order to provide a cutoff, which reduces water infiltration into the base course.

The following pavement sections provided above are based on the soil conditions encountered during our field exploration, our assumptions regarding final site grades, and limited laboratory testing.

4.8.1 Costco Pavement Design Parameters
We developed pavement design recommendations using traffic loading parameters provided in the Costco Wholesale Development Requirements and the following test data:
• A 20-year pavement design life.
• Light-duty pavements subject to 6,600 passenger vehicle trips per day (Traffic Index of

5.0).
• Heavy-duty pavements subject to 30 tractor-trailer truck tips per day (Traffic Index of 7.0). • For asphalt concrete pavements, a design R-value of 15 based on laboratory testing and engineering judgement.
• For Portland cement concrete (PCC) Pavements, a 28-day flexural strength (modulus of rupture determined by the third-point method) of at least 550 pounds per square inch (psi) (approximate compressive strength of 4,000 psi); a modulus of subgrade reaction (k value) of 100 pounds per cubic inch (pci) for native subgrade; and interlock at the control joints.

4.8.2 Asphalt Concrete Pavement
We designed asphalt concrete pavement, also referred to as Hot Mix Asphalt (HMA), in general accordance with the Caltrans Highway Design Manual (2022), which is the current design practice in California. Table 4 presents the asphalt concrete pavement sections for the noted traffic indices.

The designer should select the appropriate pavement sections based on projects requirements.

Prior to placement of aggregate base, pavement subgrade should be prepared in accordance with Section 5.2.2.

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Table 4
Recommended Minimum Asphalt Concrete Pavement Sections
Traffic Use Traffic Index, TI Design Method
Asphalt
Concrete*
(inches)
Aggregate Base*
(inches)
Light-Duty
Pavement 5.0 Caltrans 4.0 6.0
Heavy-Duty
Pavement 7.0 Caltrans 5.0 11.5
* Rounded to the closest ½ inch.

4.8.3 Asphalt Performance Grade Binder
An asphalt performance grade (PG) binder of 64-10 should be used for the project and is locally available. This recommendation was developed in accordance with Costco Wholesale Asphalt Paving Specification Section 321216. Air temperature data nearest the project site was used with the MERRA Climate Data option and the PG binder was selected using the FHWA program LTTPBind Online web-based tool based on the AASHTO M323-13 standard. The high-end and low-end temperature rating was selected to provide a reliability of at least 98 and 90 percent, respectively.

4.8.4 Portland Cement Concrete Pavement
We designed PCC pavement in accordance with the Portland Cement Association (PCA) Thickness Design for Concrete Pavements (PCA, 1984) using the design parameters stated above. For heavy-duty pavements, we recommend that PCC pavement section should be comprised of 7.0 inches of PCC with 6.0 inches of aggregate base. We understand that Costco is considering paving the American Disability Act (ADA) access area in front of the main entry with PCC pavement. For ADA access area, we recommend that PCC pavement section should be comprised of 6.0 inches of PCC with 6.0 inches of aggregate base to match the building pad flatwork. Prior to placement of aggregate base, pavement subgrade should be prepared in accordance with Section 5.2.2.

Longitudinal and transverse joint spacing should not exceed 12 feet and 15 feet, respectively.

Joint details should conform to PCA guidelines. Expansion joints in concrete slabs should be sealed with petroleum resistant sealant to prevent minor releases from impacting subsurface soil.

4.8.5 Aggregate Base
Aggregate base materials should meet current Caltrans specifications for Class 2 aggregate base.

4.8.6 Pavement Maintenance
Pavements may undergo movement due to changes in subgrade moisture content. This movement tends to accelerate pavement deterioration. A crack sealing program should be performed annually to slow pavement deterioration. Any areas where surface water stands on the surface should be remediated. Over time, as cracking becomes more pronounced, a slurry seal coat should be applied.

4.9 SOIL CORROSIVITY
We performed laboratory testing for parameters commonly used to evaluate corrosivity of soils, including pH, minimum resistivity, chloride and soluble sulfate content. Table 5 presents the results.

Table 5
Corrosion Test Results
Location Depth
(ft)
Minimum
Resistivity
(ohm-cm)
pH
Soluble
Sulfate
Content
(ppm)
Soluble
Chloride
Content
(ppm)
B-2 0-5 2,767 8.0 37 6
B-11 0-5 3,147 8.0 8 4
B-16 0-5 1,907 8.4 119 12
B-27 0-5 2,048 8.7 101 9
These tests are a generalized indicator of soil corrosivity for the samples tested. Other soils on site may be more, less, or similarly corrosive in nature. Imported fill materials should be tested to confirm that their corrosion potential is not more severe than those noted.

Although Kleinfelder does not practice corrosion engineering, resistivity values between 1,000 and 3,000 ohm-cm are normally considered highly corrosive to buried ferrous metals (Roberge, 2006). The concentrations of soluble sulfates indicate that the subsurface soils represent a Class S0 Class S0 exposure to sulfate attack on concrete in contact with the soil based on ACI 318-19 Table 19.3.1.1. Therefore, in accordance with ACI Building Code 318-19, no special provisions for selection of cement type are required.

4.10 STORMWATER MANAGEMENT
We understand that as part of the storm water management for the project, Infiltration Best Management Practices (BMPs), are being considered. We performed four (4) borehole percolation tests in general accordance with Appendix VII of the Orange County Technical Guidance Document for Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans, dated December 20, 2013. We also performed sieve analysis and hydrometer testing to assess the grain-size characteristics of the onsite soils. The results of the laboratory testing and infiltration testing results are attached in Appendix B and C, respectively.

Based on visual soil classification and laboratory testing of the soil samples collected during our field exploration, the near-surface soils generally consist of artificial fill comprised of silty to clayey sand overlying Capistrano Formation sandstone. The fines content of the infiltration test samples tested during our field exploration ranged from approximately 8 to 20 percent based on laboratory testing of the near surface soils. Table 6 summarizes the tested (in-situ) infiltration rates and the long-term design infiltration rates for each test location.

Table 6
Summary of Infiltration Test Results
Test
Location
Approximate Test Depth
(feet bgs)
Tested Infiltration Rate
(inches per hour)
Design Infiltration Rate
(inches per hour)1
INF-1 3 – 5 0.3 0.07
INF-2 8 – 10 0.1 0.02
INF-3 3 – 5 0.1 0.02
INF-4 8 – 10 0.1 0.02
Notes: 1Design Infiltration Rate determined using a combined factor of safety of 4.4, as recommended in Worksheet H: Factor of Safety and Design Infiltration Rate and Worksheet in the Orange County Technical Guidance Document for Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans, dated December 20, 2013.

Based on the results of the infiltration testing and laboratory testing, it is our opinion that the site is not considered suitable for infiltration BMPs in the subsurface soils as shown by the infiltration rates provided in Table 6. We recommend alternatives to infiltration Best Management Practices (BMPs), such as bio-filtration/bio-retention systems (bio-swales and planter boxes), be implemented at the warehouse site. If bio-filtration/bio-retention systems are employed, we recommend that the BMPs be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement. If planters are located within 10 feet of the building or building foundations, or adjacent to slabs and pavements, then some means of DRAFT
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diverting water away from the building, building foundation soils, or soils that support slabs and pavements would be required, such as lining the planters.

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5 CONSTRUCTION RECOMMENDATIONS

5.1 GENERAL
The following recommendations should be used by the contractor for construction of the project.

5.2 EARTHWORK

5.2.1 General
Site preparation and earthwork operations should be performed in accordance with applicable codes, safety regulations and other local, state or federal specifications, and the recommendations included in this report. References to maximum dry unit weights are established in accordance with the latest version of ASTM Test Method D1557 (modified Proctor).

The earthwork operations should be observed and tested by a representative of Kleinfelder.

5.2.2 Site Preparation
Abandoned utilities and other existing features within the proposed development areas (if any are encountered) should be removed and the excavation(s) backfilled with engineered fill. Debris produced by demolition operations, including wood, steel, piping, plastics, etc., should be separated and disposed of off-site. Existing utility pipelines or conduits that extend beyond the limits of the proposed construction and are to be abandoned in place, should be plugged with non-shrink cement grout to prevent migration of soil and/or water. Demolition, disposal, and grading operations should be observed and tested by a representative of Kleinfelder.

Soils within 10 feet of the warehouse pad (including the entrance canopy, building aprons, utility pads, stairs, ramps, stoops, and the loading dock) should be overexcavated to a depth of at least 5 feet below existing grade or 3 feet below the bottom of the footings and floor slabs, whichever is deeper, and replaced as structural fill. Depending on the condition of the fill at the base of the excavation, additional overexcavation may be required. The overexcavated soils can be moisture conditioned and recompacted as structural fill. Following overexcavation and prior to replacing soils, the exposed subgrade should be proof-rolled with heavy construction equipment (e.g., with a fully-loaded tandem-axle dump truck or water truck). Areas identified as being soft or yielding may require additional compaction or overexcavation as determined by Kleinfelder.

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drum roller) after the area has been stripped of soft earth materials and construction debris to disclose areas of soft and yielding material. Where soft and yielding material is observed, it should be overexcavated and replaced as structural fill. The proof-rolling should extend beyond the proposed improvements a horizontal distance of at least 2 feet, where possible.

Following overexcavation and prior to replacing soils, the exposed subgrade should be proof rolled with at least a 10-ton roller, fully loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding may require additional compaction or overexcavation as determined by Kleinfelder. Following proof rolling and any additional overexcavation, the exposed subgrade should be scarified at least 6 to 8 inches, moisture conditioned, and recompacted.

5.2.3 Foundation Excavations
Shallow Foundations
Following excavation to the foundation subgrade elevations, the exposed subgrade should be observed by a representative of the geotechnical engineer to evaluate the presence of satisfactory materials at design elevations. If unsatisfactory material, such as soft or disturbed soil, debris or otherwise unsuitable soil is present at the base of footing excavations, it should be overexcavated and replaced with structural concrete, 2-sack sand-cement slurry, or structural fill to the depth determined by the geotechnical engineer.

Drilled Pile Foundations
The performance and capacities of piles can be influenced significantly by the selected construction methods and procedures used. Construction methods that create large zones of disturbance around the drilled shafts can lead to lower than expected skin friction due to excessive stress relief around the shaft length. Drilling of the pile shafts should be accomplished using conventional heavy-duty excavation equipment maintained in good condition. However, drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone.

Caving of the pile shafts could occur in non-cohesive sandy layers. Temporary steel casing may be required to stabilize the sides of the pile shaft. Concrete should be placed immediately after drilling of the hole is complete. The concrete should be pumped to the bottom of the drilled shaft using a down-hole tremie. If the tremie method is used to place concrete below the water level, we recommend it have a slump of at least 8 inches. If steel casing is used, the casing should be DRAFT
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removed as the concrete is placed but the bottom of the casing should be kept at least 5 feet below the top of the concrete.

5.2.4 Fill Material and Compaction Criteria
The on-site soils, minus debris, organic matter, or other deleterious materials may be used as structural fill. Rock or other soil fragments greater than 3 inches in size should not be used in the fills.

Import soils, if needed, should have no particles greater than 3 inches in maximum dimension, no less than 70 percent of the particles passing the No. 4 sieve, no more than 30 percent of particles passing the No. 200 sieve, and a Plasticity Index (PI) less than 5. The contractor should provide documentation that all imported soil is free of hazardous materials, including petroleum or petroleum byproducts, chemicals and harmful minerals. Test results with the geotechnical and analytical properties of the proposed import material should be provided to Costco for approval prior to transportation and use on site.

Soils should be compacted to at least 95 percent of the maximum dry unit weight (ASTM D1557) in accordance with the Costco Wholesale Development Requirements (CWDRs). Fill should be placed in loose horizontal lifts not more than 8 inches thick (loose measurement). The moisture content of the fill should be maintained at within 2 percent of optimum during compaction.

Processing may require ripping the material, disking to break up clumps, and blending to attain uniform moisture contents necessary for compaction. Utility trench backfill should be mechanically compacted. Flooding should not be permitted. Table 7 presents structural fill placement and compaction criteria.

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Table 7
Structural Fill Placement And Compaction Criteria
Fill Location/Use Material
Type
Relative Compaction1
(ASTM D1557)
Moisture
Content
Range
Minimum
Compaction
Testing Frequency
Per Lift
Aggregate Base
Course for
Pavements and
Concrete Slabs
Aggregate
Base At least 95 percent -2 to +2%of optimum 10,000 Square Feet Structural Areas
(Warehouse
Building Pad)
On-site Soils
or Imported
Material
At least 95 percent -2 to +2%
of optimum 10,000 Square Feet
Subgrade for
Pavements,
Sidewalks and
Other Flatwork
Areas
On-site Soils
or Imported
Material
At least 95 percent -2 to +2%
of optimum 15,000 Square Feet
Retaining Wall
Backfill
On-site
Granular
Soils or
Imported
Material
At least 92 percent -2 to +2%
of optimum 1,000 Square Feet
Utility Trenches
Backfill
On-site Soils
or Imported
Material
At least 95 percent -2 to +2%
of optimum 150 Linear Feet
Lawns or
Unimproved Areas
On-site Soils
or Imported
Material
At least 90 percent At least
optimum 20,000 Square Feet
Note: 1 Where two or more compaction specifications coincide, the more stringent specification should be utilized.

5.2.5 Shrinkage/Bulking
For earthwork volume estimating purposes, an average shrinkage value of 5 to 10 percent for the upper fill soils (generally in the upper 5 to 6 feet) may be assumed. These values are estimates only and exclude losses due to removal of vegetation or debris. Actual shrinkage/bulking factors will depend on the types of earthmoving equipment used and should be determined during grading. We recommend that the civil engineer or the contractor contact a local earthwork contractor to confirm these values prior to finalizing any earthwork estimates.

5.2.6 Excavation Characteristics
The subsurface conditions consist predominantly of artificial fill overlying Capistrano Formation sandstone. Refusal was not encountered in any of the borings drilled to a maximum depth of approximately 49½ feet bgs. The excavations for foundations, utility trenches and general site grading should be excavatable with conventional heavy-duty construction equipment maintained DRAFT
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in good condition; however, localized cemented zones may require more aggressive means of excavation such as a large hydraulic excavator equipped with either a rock ripping attachment or a pneumatic hammer to break up and excavate the bedrock. The contractor should consider these soil conditions in determining the equipment required for the on-site excavations. In addition, oversized materials, such as rock fragments or cobbles, should be anticipated. Oversize material larger than 3 inches in diameter should be removed and disposed of off-site. Caving of the sidewalls during excavation in the sandy soil may occur depending on conditions at the time of excavation and should be anticipated by the contractor.

5.2.7 Temporary Excavations
All excavations must comply with applicable local, state, and federal safety regulations, including OSHA requirements. The responsibility for excavation safety and stability of temporary construction slopes lies solely with the contractor. We are providing this information below solely as a service to our client. Under no circumstances should this information provided be interpreted to mean that Kleinfelder is assuming responsibility for final engineering of excavations or shoring, construction site safety, or the contractors’ activities; such responsibility is not being implied and should not be inferred.

Minor sloughing and/or raveling of slopes should be anticipated as they dry out. Where space for sloped embankments is not available, shoring will be necessary. In addition, excavations within a 1:1 plane extending downward from a horizontal distance of 2 feet beyond the bottom outer edge of existing improvements should not be attempted without bracing and/or underpinning the footings, as discussed above. The geotechnical engineer or their field representative should observe the excavations so that modifications can be made to the excavations, as necessary, based on variations in the encountered soil conditions. All applicable excavation safety requirements and regulations, including OSHA requirements, should be met.

Vertical or steeply sided trench excavations should not be attempted without proper shoring or bracing. All trench excavations should be braced and shored in accordance with good construction practice and all applicable safety ordinances and codes. Stockpiled (excavated) materials should be placed no closer to the edge of an excavation than a distance equal to the depth of the excavation, but no closer than 4 feet.

5.2.8 Trench Backfill
Pipe zone backfill (i.e. material beneath and in the immediate vicinity of the pipe) should consist of imported soil less than ¾-inch in maximum dimension. Trench zone backfill (i.e., material DRAFT
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placed between the pipe zone backfill and finished subgrade) may consist of onsite soil or imported fill that meets the requirements for engineered fill provided above.

If imported material is used for trench zone backfill, we recommend it consist of silty sand. In general, gravel should not be used for trench zone backfill due to the potential for soil migration into the relatively large void spaces present in this type of material and for water seepage along trenches backfilled with coarse-grained sand and/or gravel.

Recommendations provided above for pipe zone backfill are minimum requirements only. More stringent material specifications may be required to fulfill local building requirements and/or bedding requirements for specific types of pipes. We recommend the project civil engineer develop these material specifications based on planned pipe types, bedding conditions, and other factors beyond the scope of this study.

Trench backfill should be placed and compacted in accordance with recommendations provided for engineered fill in Section 5.2.4. Mechanical compaction is recommended; ponding or jetting should be avoided, especially in areas supporting structural loads or beneath concrete slabs supported on grade, pavements, or other improvements.

5.3 UNSTABLE SUBGRADE CONDITIONS
Should grading be performed during or following extended periods of rainfall, the moisture content of the near-surface soils may be significantly above the optimum moisture content. These conditions could seriously impede grading by causing an unstable subgrade condition. Typical remedial measures for the site conditions include the following. • Drying: Drying unstable subgrade involves disking or ripping wet subgrade to a depth of approximately 18 to 24 inches and allowing the exposed soil to dry. Multiple passes of the equipment (likely on a daily basis) will be needed because as the surface of the soil dries, a crust forms that reduces further evaporation. Frequent disking will help prevent the formation of a crust and will promote drying. This process could take several days to several weeks depending on the material, the depth of ripping, the number of passes, and the weather.
• Removal and Replacement with Crushed Rock and Geotextile Fabric: Unstable subgrade could be overexcavated 12 to 24 inches below existing grade and replaced with ¾- or 1-inch crushed rock underlain by geotextile fabric. The geotextile fabric should consist of a woven geotextile, such as Mirafi HP series or equivalent. The final depth of removal will DRAFT
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depend upon the conditions observed in the field once overexcavation begins. The geotextile fabric should be placed in accordance with the manufacturer’s recommendations.
• Cement Treatment: For larger areas, unstable subgrade could be stabilized by mixing the upper 12 to18 inches of the subgrade with Portland cement. For estimating purposes, an application rate of 4 to 5 percent Portland cement may be used. Final application rates should be determined in the field at the time of construction in consultation with the geotechnical engineer. Cement treatment should be performed by a specialty contractor experienced in this work. Since soil treatment uses the on-site soil, the expense of importing material can be avoided.

5.4 TEMPORARY SHORING
Temporary shoring may be required in areas adjacent to existing structures or improvements where excavations cannot be adequately sloped. Temporary shoring may consist of a turn-key shoring system, soldier piles and lagging, or other system. Recommendations for design of temporary shoring are presented below.

The shoring design should be provided by a civil engineer registered in the State of California and experienced in the design and construction of shoring under similar conditions. Once the final excavation and shoring plans are complete, the plans and design should be reviewed by Kleinfelder for conformance with the design intent and geotechnical recommendations provided herein.

5.4.1 Lateral Pressures
For the design of cantilevered shoring, an equivalent fluid pressure of 40 pounds per cubic foot (pcf) may be used for level backfill. Where the surface of the retained earth slopes up away from the shoring, a greater pressure should be used. Design data can be developed for additional cases when the design conditions are established.

In addition to the recommended earth pressure, any surcharge (live, including traffic, or dead load) located within a 1:1 plane drawn upward from the base of the shored excavation should be added to the lateral earth pressures. The lateral contribution of a uniform surcharge load located immediately behind the wall may be calculated by multiplying the surcharge by 0.33 for the level backfill condition. Lateral load contributions of surcharges located at a distance behind the shored wall may be provided once the load configurations and layouts are known. As a minimum, a 2- DRAFT
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foot equivalent soil surcharge (250 psf) is recommended to account for nominal construction loads. It should be noted that the above pressures do not include hydrostatic pressure and assume groundwater will not be encountered in the excavation, or dewatering will be used to lower the ground water table below the bottom of the excavation.

5.4.2 Design of Soldier Piles
All soldier piles should extend to a sufficient depth below the excavation bottom to provide the required lateral resistance. We recommend the required embedment depths be calculated based on the principles of force and moment equilibrium. For this method, the allowable passive pressure against soldier piles that extend below the level of excavation may be assumed to be equivalent to a fluid pressure of 250 pcf. The maximum lateral resistance value should not exceed 2,500 psf. To account for arching, the passive resistance may be assumed to act over a width 2.5 times the width of the embedded portion of the pile, provided adjacent piles are spaced at least

3.0 pile diameters, center-to-center.

Drilling of the soldier pile shafts could be accomplished using heavy-duty drilling equipment. The on-site soils below the base of the excavation are sandy and caving of the pile shafts could occur.

Temporary steel casing may be required to stabilize the sides of the pile shaft. Concrete for piles should be placed immediately after the drilling of the hole is complete. The concrete should be pumped to the bottom of the drilled shaft using a tremie. Once concrete pumping is initiated, a minimum head of 5 feet of concrete above the bottom of the tremie should be established and maintained throughout the concrete placement to prevent contamination of the concrete by soil inclusions. If steel casing is used, the casing should be removed as the concrete is placed.

To develop full lateral resistance, provisions should be taken to assure firm contact between the soldier piles and undisturbed materials. The concrete placed in the soldier pile excavations may be a lean-mix concrete. However, the concrete used in that portion of the soldier pile that is below the planned excavated level should provide sufficient strength to adequately transfer the imposed loads to the surrounding materials.

5.4.3 Lagging
Continuous treated timber lagging should be used between the soldier piles. The lagging should be installed as the excavation proceeds. If treated timber is used, the lagging may remain in place after backfilling. The lagging should be designed for the recommended earth pressure but limited to a maximum value of 400 psf.

5.4.4 Deflection
Shoring adjacent to existing structures or improvements should be designed and constructed to reduce potential movement. The shoring system designer should evaluate potential deflections in their design.

5.4.5 Monitoring
Some deflection of the shored excavation should be anticipated during the planned excavation.

We recommend the project civil engineer perform a survey of all existing utilities and structures adjacent to the shored excavation. The purpose of this survey would be to evaluate the ability of existing utility lines or improvements to withstand horizontal movements associated with a shored excavation and to establish the baseline condition in case of unfounded claims of damage. If existing improvements are not capable of withstanding anticipated lateral movements, alternative shoring systems may be required.

Horizontal and vertical movements of the shoring system should be monitored by a licensed surveyor. The construction monitoring and performance of the shoring system are ultimately the contractor’s responsibility. However, at a minimum, we recommend that the top of shoring be surveyed prior to excavation and that the top and bottom of the soldier beams be surveyed on a weekly basis until the shoring is not needed. Surveying should consist of measuring movements in vertical and two perpendicular horizontal directions.

5.5 EXTERIOR FLATWORK
Prior to casting exterior flatwork, the existing soils should be overexcavated and subgrade soils should be scarified, moisture conditioned, and recompacted as recommended in Section 5.2.2.

The moisture content of the finished subgrade soils should be maintained around optimum prior to the placement of any flatwork or structural fill. Careful control of the water/cement ratio should be performed to avoid shrinkage cracking due to excess water or poor concrete finishing or curing.

5.6 PAVEMENTS

5.6.1 HMA Design
Hot Mix Asphalt (HMA) should conform to requirements of the Costco Wholesale Specification Section 321216, Asphalt Paving. Section 1.3.C of the HMA specification requires that the HMA section be placed in at least two lifts. The HMA specification allows the use of ½- or ¾-inch Nominal Maximum Aggregate Size (NMAS) mixes for the base course and ⅜- or ½-inch NMAS DRAFT
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mixes for surface course. Maximum and minimum HMA compacted lift thicknesses are provided in Table 3.1 in Section 3.3.B of the HMA specification.

5.6.2 Construction Considerations
The pavement sections provided above are contingent on the following recommendations being implemented during construction.
• Pavement subgrade should be prepared as recommended in Section 5.2.2. • Subgrade soils should be in a stable, non-pumping condition at the time the aggregate base materials are placed and compacted.
• Aggregate base materials should be compacted to at least 95 percent relative compaction (ASTM D1557).
• Asphalt paving materials and placement methods should meet current Costco Wholesale Specifications Section 321216.
• Adequate drainage (both surface and subsurface) should be provided such that the subgrade soils and aggregate base materials are not allowed to become wet.

Note that pavement materials and construction must be completed in strict accordance with the Costco’s specifications that contain very specific pavement material (asphalt, aggregate and concrete) criteria and construction practices to be used (compaction and material sampling). The general contractor and pavement construction subcontractor should be aware that asphalt and concrete mix designs must be submitted to the design architect and Kleinfelder at least 45 days prior to the scheduled production and laydown for review and approval.

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6 ADDITIONAL SERVICES

6.1 PLANS AND SPECIFICATIONS REVIEW
We recommend Kleinfelder perform a review of geotechnical-related portions of the project plans and specifications before they are finalized to see that geotechnical recommendations have been properly interpreted and implemented during design. If we are not accorded the privilege of performing this review, we can assume no responsibility for misinterpretation of our recommendations.

6.2 CONSTRUCTION OBSERVATION AND TESTING
The construction process is an integral design component with respect to the geotechnical aspects of a project. Because geotechnical engineering is an inexact science due to the variability of natural processes, and because we sample only a limited portion of the soils affecting the performance of the proposed structure, unanticipated or changed conditions can be encountered during grading. Proper geotechnical observation and testing during construction are imperative to allow the geotechnical engineer the opportunity to verify assumptions made during the design process. Therefore, we recommend that Kleinfelder be retained during the construction of the proposed improvements to observe compliance with the design concepts and geotechnical recommendations, and to allow design changes in the event that subsurface conditions or methods of construction differ from those assumed while completing this study.

Our services are typically needed at the following stages of grading:
• After demolition;
• During grading;
• During the installation of temporary construction shoring; • After the overexcavation, but prior to subgrade preparation; • During utility trench backfill;
• During fill placement of wall backfill;
• During base placement and site paving; and
• After excavation for foundations.

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7 LIMITATIONS
This geotechnical study has been prepared for the exclusive use of Costco Wholesale and their agents for specific application to the proposed Costco Wholesale Warehouse and Fuel Facility (CW# 24-1218) located at 26602 Towne Centre Drive in Foothill Ranch, California. The findings, conclusions, and recommendations presented in this report were prepared in accordance with generally accepted geotechnical engineering practice. No other warranty, express or implied, is made.

The scope of services was limited to a background data review and the field exploration described in Section 1.2. It should be recognized that definition and evaluation of subsurface conditions are difficult. Judgments leading to conclusions and recommendations are generally made with incomplete knowledge of the subsurface conditions present due to the limitations of data from field studies. The conclusions of this assessment are based on our field exploration and laboratory testing programs, and engineering analyses.

Kleinfelder offers various levels of investigative and engineering services to suit the varying needs of different clients. Although risk can never be eliminated, more detailed and extensive studies yield more information, which may help understand and manage the level of risk. Since detailed study and analysis involves greater expense, our clients participate in determining levels of service, which provide information for their purposes at acceptable levels of risk. The client and key members of the design team should discuss the issues covered in this report with Kleinfelder, so that the issues are understood and applied in a manner consistent with the owner’s budget, tolerance of risk and expectations for future performance and maintenance.

Recommendations contained in this report are based on our field observations and subsurface explorations, limited laboratory tests, and our present knowledge of the proposed construction. It is possible that soil or groundwater conditions could vary between or beyond the points explored. If soil or groundwater conditions are encountered during construction that differ from those described herein, the client is responsible for ensuring that Kleinfelder is notified immediately so that we may reevaluate the recommendations of this report. If the scope of the proposed construction, including the estimated Traffic Index or locations of the improvements, changes from that described in this report, the conclusions and recommendations contained in this report are not considered valid until the changes are reviewed, and the conclusions of this report are modified or approved in writing, by Kleinfelder.

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The scope of services for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site.

Kleinfelder cannot be responsible for interpretation by others of this report or the conditions encountered in the field. Kleinfelder must be retained so that all geotechnical aspects of construction will be monitored on a full-time basis by a representative from Kleinfelder, including site preparation, preparation of foundations, and placement of engineered fill and trench backfill. These services provide Kleinfelder the opportunity to observe the actual soil and groundwater conditions encountered during construction and to evaluate the applicability of the recommendations presented in this report to the site conditions. If Kleinfelder is not retained to provide these services, we will cease to be the engineer of record for this project and will assume no responsibility for any potential claim during or after construction on this project. If changed site conditions affect the recommendations presented herein, Kleinfelder must also be retained to perform a supplemental evaluation and to issue a revision to our original report.

This report, and any future addenda or reports regarding this site, may be made available to bidders to supply them with only the data contained in the report regarding subsurface conditions and laboratory test results at the point and time noted. Bidders may not rely on interpretations, opinion, recommendations, or conclusions contained in the report. Because of the limited nature of any subsurface study, the contractor may encounter conditions during construction which differ from those presented in this report. In such event, the contractor should promptly notify the owner so that Kleinfelder’s geotechnical engineer can be contacted to confirm those conditions. We recommend the contractor describe the nature and extent of the differing conditions in writing and that the construction contract include provisions for dealing with differing conditions. Contingency funds should be reserved for potential problems during earthwork and foundation construction.

This report may be used only by the client and only for the purposes stated, within a reasonable time from its issuance, but in no event later than one year from the date of the report. Land use, site conditions (both on site and off site) or other factors may change over time, and additional work may be required with the passage of time. Any party, other than the client who wishes to use this report shall notify Kleinfelder of such intended use. Based on the intended use of this report and the nature of the new project, Kleinfelder may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the client or anyone else will release Kleinfelder from any liability resulting from the use of this report by any unauthorized party and the client agrees to defend, indemnify, and hold harmless Kleinfelder from any claims or liability associated with such unauthorized use or non-compliance.

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8 REFERENCES
American Concrete Institute (ACI), 2019. Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI318-19R).

American Society of Civil Engineers (ASCE), 2016, Minimum Design Load for Buildings and Other Structures (ASCE/SEI 7-16) with ASCE Supplement 1, 2, and 3.

California Department of Conservation, Geologic Energy Management Division (CalGEM), 2024, Well Finder, Well Finder (ca.gov)
California Geological Survey (CGS), 2025. California Landslide Inventory and Susceptibility to Deep-Seated Landslides in California (2011). Landslide Inventory Beta. Landslide Inventory (Beta) (ca.gov) Accessed February, 2025.

California Geological Survey (CGS), 2018, Earthquake Fault Zones - A Guide for Government Agencies, Property Owners/Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California: California Geological Survey Special Publication 42, 83p.

California Geological Survey (CGS), 2003, Earthquake Fault Zones, Corona South Quadrangle, California 7.5 Minute Series: California Geological Survey, Revised Official Map Effective May 1, 2003.

California Geologic Survey (CGS), 2002, California Geomorphic Provinces, Note 36, California Dept. of Conservation, Sacramento, California.

California Geological Survey (CGS), 2001, Earthquake Zones of Required Investigations, 7.5- Minute Lake Forest Quadrangle (Previously El Toro Quadrangle); Official Map, released January 17, 2001.

Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, California Geological Survey, available at "http://www.conservation.ca.gov/"
Costco, 2022. Costco Wholesale Development Requirements, Version 2022, dated October 28, 2022.

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Dawson, T.E., and R.J. Weldon, 2013, Appendix B - Geologic Slip Rate Data and Geologic Deformation Model in Field, et al. 2013, Uniform California earthquake rupture forecast, version 3 (UCERF3) - The time-independent model: U.S. Geological Survey (USGS) Open-File Report 2013–1165, and California Geological Survey (CGS) Special Report 228.

Division of Safety of Dams, 2025, Dam Breach Inundation Map Web Publisher. Dam Breach Inundation Map Web Publisher (ca.gov), Accessed February 2025.

Federal Emergency Management Agency (FEMA), 2009, FIRM, Flood Insurance Rate Map, City of Lake Forest, California, Map Number 06059C0316J, Effective Date December 3, 2009 Grant, L.B. , Ballenger, L.J., and Runnerstrom, E.E., 2002, Coastal Uplift of the San Joaquin Hills, Southern Los Angeles Basin, California, by a Large Earthquake since A.D. 1635: Bulletin of the Seismological Society of America, Volume 92, No. 2, pp. 590-599 Grant, L.B., Mueller, K. J., Gath, E. M., Cheng, H., Edwards, R. L., Munro, R., and Kennedy, G.

L., 1999, Late Quaternary uplift and earthquake potential of the San Joaquin Hills, southern Los Angeles basin, California: Geology, Volume 27, No. 11, pp. 1031–1034.

International Code Council, Inc., 2022 California Building Code.

MG2, 2022, Preliminary Site Plan, Costco Wholesale, Foothill Ranch, CA, Sheet P11-09, dated December 17, 2024.

Montrose Environmental, 2025, Second Semi-Annual 2024 Groundwater Monitoring Report Former Palisades Gas and Wash Station No. 824 26731 Portola Parkway, Lake Forest, California, Project No. 006531, Case No. 14UT002, dated January 9, 2025 Morton, D.M. and Miller, F.K., 2006, Geologic map of Santa Ana 30’ x 60’ Quadrangle, California:

United States Geological Survey Open-File Report 2006-1217, scale 1:100,000.

Orange County Water District (OCWD), City of La Habra and Irvine Ranch Water District (IRWD), 2022, Basin 8-1 Alternative 2022 Update, dated January 1, 2022.

PBLA Surveying, Inc., 2025, A.L.T.A./N.S.P.S. Land Title Survey, City of Foothill Ranch, County of Orange, State of California, Job No. 5001-1056, 6 Sheets, dated February 3, 2025.

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Petersen, M.D., Frankel, A.D., Harmsen, S.C., Mueller, C.S., Haller, K., Wheeler, R.L., Wesson, R.L., Zeng, Y., Boyd, O.S., Perkins, D.M., Luco, N., Field, E.H., Wills, C.J., and Rukstales, K.S., 2008, Documentation for the 2008 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey (USGS), Open-File Report 2008–1128, 61p.

Portland Cement Association (PCA), 1984, Thickness Design for Concrete Highway and Street Pavements, Skokie, Illinois: Portland Cement Association.

Portland Cement Association, 1988. Design and Control of Concrete Mixtures, Portland Cement Association, Skokie, Illinois.

Pridmore, C.L., 2000, Liquefaction Zones in the El Toro 7.5-Minute Quadrangle, Orange County, California in Seismic Hazard Zone Report for the El Toro 7.5-Minute Quadrangle, Orange County, California: California Geological Survey Seismic Hazard Zone Report 047, pp. 3- 18.

Roberge, P., 2006, Corrosion Basics, 2nd ed.

Schoellhamer, J.E., Vedder, J.G., Yerkes, R.F., and Kinney, D.M., 1981, Geology of the Northern Santa Ana Mountains, California: U.S. Geologic Survey Professional Paper 420-D, 109p, 4 plates, Map Scale 1:24,000.

Singer, J.A. 1973, Geohydrology and artificial-recharge potential of the Irvine area, Orange County, California: U.S. Geological Survey Open File Report 73-264, 41p.

State of California, 2021, Tsunami Hazard Area Map, Orange County; produced by the California Geological Survey and the California Governor's Office of Emergency Services; dated 2021, displayed at multiple scales.

United States Geological Survey (USGS), 2025, Areas of Land Subsidence in California, website accessed February, 2025 at: Subsiding Areas in California | USGS California Water Science Center
United States Geological Survey (USGS), 1949, El Toro Quadrangle, Orange County, California:

7.5 Minute Series (Topographic) 1:24,000 scale.

United States Geologic Survey (USGS) and California Geological Survey (CGS), Quaternary fault and fold database for the United States, accessed February 5, 2025 at https://www.usgs.gov/programs/earthquake-hazards/faults DRAFT
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FIGURES
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The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg N
DRAWN BY:

PROJECT:

CHECKED BY:

REVISED:

DATE:

FIGURE SITE VICINITY MAP 25003229
DMF
HM
01/2025
- 1
2,000 1,000 0 2,000
APPROXIMATE SCALE (feet)
SOURCE: U.S.G.S. 7.5' topographic series, Lake Forest,
California quadrangle, dated 2022.

PLOTTED: 1/20/2025 7:10 PM BY: dean fahrney
SITE

PROPOSED COSTCO WHOLESALE WAREHOUSE

AND FUEL FACILITY
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
DRAFT
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© 2025 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg LAYOUT: 2 PLOTTED: 2/6/2025 10:10 AM BY: dean fahrney The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

N
150 75 0 150
APPROXIMATE SCALE (feet)
FIGURE

DRAWN BY
DATE:

PROJECT:

CHECKED BY
REVISED:

EXPLORATION LOCATION MAP 25003229
DMF
HM
01/2025
-
PROPOSED COSTCO WHOLESALE WAREHOUSE 2

AND FUEL FACILITY
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA

TOWNE CENTER DR

MARKET PL
FOOTHILL TRANSPORTATION CORRIDOR - 241

EXPLANATION
B-28 APPROXIMATE BORING LOCATION
B-21
B-5 B-22
B-6
B-24
B-4
B-14
B-11
B-13
B-15
B-12
B-20
B-19
B-26
B-25
B-28
B-16
B-17
B-18
B-27
B-23
B-8
B-2
B-3
B-1
B-10
B-9
B-7
INF-4 APPROXIMATE INFILTRATION TEST LOCATION
INF-4
INF-3
INF-2
INF-1
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APPENDIX A

FIELD EXPLORATIONS
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APPENDIX A

FIELD EXPLORATIONS

GENERAL
Subsurface conditions at the site were explored by drilling 28 borings. In addition, 4 borehole infiltration tests were performed. The borings and infiltration tests were drilled by 2R Drilling, Inc. using truck-mounted, hollow-stem-auger drilling equipment to depths of between approximately 5 and 49½ feet below the existing ground surface (bgs) in the warehouse building, fuel facility, parking and drive areas. The approximate locations of the borings and infiltration tests are presented on Figure 2.

Prior to commencement of the fieldwork, Underground Service Alert (USA) was notified and various geophysical techniques were used at the exploration locations to identify potential conflicts with subsurface structures.

The boring and infiltration test logs are presented as Figures A-4 through A-37. An explanation to the logs is presented as Figures A-1 through A-3. The exploration logs describe the earth materials encountered, samples obtained and show field and laboratory tests performed. The logs also shows the location, boring number, drilling date and the name of the drilling subcontractor.

The borings were logged by a Kleinfelder engineer or geologist using the Unified Soil Classification System. The boundaries between soil types shown on the logs are approximate because the transition between different soil layers may be gradual. Bulk and drive samples of selected earth materials were obtained from the borings.

A modified-California sampler was used to obtain drive samples of the soil encountered. This sampler consists of a 3-inch O.D., 2.4-inch I.D. split barrel shaft that is pushed or driven a total of 18-inches into the soil at the bottom of the boring. The soil was retained in six 1-inch brass rings for laboratory testing. An additional 2 inches of soil from each drive remained in the cutting shoe and was usually discarded after visually classifying the soil. The sampler was driven using a 140-pound hammer falling 30 inches. The total number of blows required to drive the sampler the final 12 inches is termed blow count and is recorded on the Log of Boring.

Samples were also obtained using a Standard Penetration Sampler (SPT). This sampler consists of a 2-inch O.D., 1-inch I.D. split barrel shaft that is advanced into the soils at the bottom of the drill hole a total of 18 inches. The sampler was driven using a 140-pound hammer falling 30 inches. The total number of hammer blows required to drive the sampler the final 12 inches is DRAFT
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© 2025 Kleinfelder www.kleinfelder.com
termed the blow count (N) and is recorded on the Log of Boring. The procedures we employed in the field are generally consistent with those described in ASTM Standard Test Method D1586.

Bulk and grab samples of the near-surface soils were directly retrieved from the auger cuttings from the borings.

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A-1

FIGURE GRAPHICS KEY
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
The report and graphics key are an integral part of these logs. All data and interpretations in this log are subject to the explanations and limitations stated in the report.

Solid lines separating strata on the logs represent approximate boundaries only, dashed lines are inferred or extrapolated boundaries.

Actual transitions may be gradual or differ from those represented.

No warranty is provided as to the continuity of soil or rock conditions between individual sample locations.

Logs represent general soil or rock conditions observed at the point of exploration on the date indicated.

In general, Unified Soil Classification System (ASTM D2488/D2487) designations presented on the logs were based on visual classification in the field and were modified where appropriate based on gradation and index property testing.

Fine grained soils that plot within the hatched area on the Plasticity Chart, and coarse grained soils with between 5% and 12% passing the No. 200 sieve require dual USCS symbols, ie., CL-ML, GW-GM, GP-GM, GW-GC, GP-GC, GC-GM, SW-SM, SP-SM, SW-SC, SP-SC, SC-SM.

If sampler is not able to be driven at least 6 inches then 50/X indicates number of blows required to drive the identified sampler X inches with a 140 pound hammer falling 30 inches.

ABBREVIATIONS
Cu - Coefficients of Uniformity
CC - Coefficients of Curvature
WOH - Weight of Hammer
WOR - Weight of Rod

REFERENCES

1. American Society for Testing and Materials (ASTM), 2011, ASTM D2487: Classification of Soils for Engineering Purposes (Unified Soil Classification System).

GRAVELS
WITH >
12%
FINES

SILTS AND CLAYS
(Liquid Limit
less than 50)

WELL-GRADED GRAVEL WITH SILT,

WELL-GRADED GRAVEL WITH SILT AND SAND

POORLY GRADED GRAVEL WITH CLAY (OR SILTY

CLAY), POORLY GRADED GRAVEL WITH CLAY AND
(OR SILTY CLAY AND SAND)

SILTY GRAVEL,

SILTY GRAVEL WITH SAND

CLAYEY GRAVEL,

CLAYEY GRAVEL WITH SAND

POORLY GRADED GRAVEL WITH SILT,

POORLY GRADED GRAVEL WITH SILT AND SAND
SP
CLEAN
SANDS
WITH
<5%
FINES

ML SILT, SILT WITH SAND, SILT WITH GRAVEL CL

ORGANIC CLAY, ORGANIC CLAY WITH SAND, ORGANIC CLAY WITH GRAVEL, ORGANIC SILT, ORGANIC SILT WITH SAND, ORGANIC SILT WITH GRAVEL

ORGANIC CLAY, ORGANIC CLAY WITH SAND, ORGANIC CLAY WITH GRAVEL, ORGANIC SILT, ORGANIC SILT WITH SAND, ORGANIC SILT WITH GRAVEL CL-ML

WELL-GRADED GRAVEL WITH CLAY (OR SILTY

CLAY), WELL-GRADED GRAVEL WITH CLAY AND

SAND (OR SILT CLAY AND SAND)

SILTY CLAY, SILTY CLAY WITH SAND, SILTY CLAY WITH GRAVEL ELASTIC SILT. ELASTIC SILT WITH SAND, ELASTIC SILT WITH GRAVEL

FAT CLAY, FAT CLAY WITH SAND, FAT CLAY WITH GRAVEL
OL
SANDS
WITH >
12%
FINES
CLEAN
GRAVEL
WITH
<5%
FINES

GRAVELS
WITH
5% TO
12%
FINES
SW
SW-SC
SW-SM
SC-SM
GP-GM

SILTY, CLAYEY GRAVEL

SILTY, CLAYEY GRAVEL WITH SAND

WELL-GRADED SAND,

WELL-GRADED SAND WITH GRAVEL

POORLY GRADED SAND,

POORLY GRADED SAND WITH GRAVEL

WELL-GRADED SAND WITH SILT,

WELL-GRADED SAND WITH SILT AND GRAVEL

POORLY GRADED SAND WITH SILT,

POORLY GRADED SAND WITH SILT AND GRAVEL

POORLY GRADED SAND WITH CLAY,

POORLY GRADED SAND WITH CLAY AND GRAVEL
(OR SILTY CLAY AND GRAVEL)

SILTY SAND,

SILTY SAND WITH GRAVEL
GP-GC
GC-GM

FINE GRAINED SOILS
(50% or more passes
the No. #200 sieve)

WELL-GRADED GRAVEL,

WELL-GRADED GRAVEL WITH SAND

POORLY GRADED GRAVEL,

POORLY GRADED GRAVEL WITH SAND

WELL-GRADED SAND WITH CLAY (OR SILTY CLAY),

WELL-GRADED SAND WITH CLAY AND GRAVEL
(OR SILTY CLAY AND GRAVEL)

CLAYEY SAND,

CLAYEY SAND WITH GRAVEL
COARSE GRAINED SOILS (More than 50% retained on No. 200 Sieve)

SILTY, CLAYEY SAND,

SILTY, CLAYEY SAND WITH GRAVEL

LEAN CLAY, LEAN CLAY WITH SAND, LEAN CLAY WITH GRAVEL

SILTS AND CLAYS
(Liquid Limit
50 or greater)
NOTE: USE MATERIAL DESCRIPTION ON THE LOG TO DEFINE A GRAPHIC THAT MAY NOT BE PROVIDED ON THIS LEGEND.

MH
CH
OH

BULK SAMPLE

CALIFORNIA SAMPLER
(3 in. (76.2 mm.) outer diameter)

GRAB SAMPLE

STANDARD PENETRATION SPLIT SPOON SAMPLER
(2 in. (50.8 mm.) outer diameter and 1-3/8 in. (34.9 mm.) inner diameter)
UNIFIED SOIL CLASSIFICATION SYSTEM1
SP-SM
SP-SC
SM
SC
SANDS
WITH
5% TO
12%
FINES
GM
GC
GW
GP
GW-GM
GW-GC
SANDS (50% or more of coarse fraction passes the No. 4 Sieve) GRAVELS (More than 50% of coarse fraction retained on No. 4 Sieve)

DRILLING METHOD/SAMPLER TYPE GRAPHICS
NOTES

GROUND WATER GRAPHICS

OBSERVED SEEPAGE
WATER LEVEL (level where first observed)
WATER LEVEL (additional levels after exploration)
WATER LEVEL (level after stabilizing period)
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CHECKED BY: H.M
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PROJECT NO.:

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SPT-N
(# blows / ft)
FIGURE
A-2

SOIL DESCRIPTION KEY
(For additional tables, see ASTM D2488)
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
coarse
fine
Gravel
Same color and appearance throughout
Breaks along definite planes of fracture with
little resistance to fracturing.

Homogeneous

DESCRIPTION
Alternating layers of varying material or color with layers at least 1/4-in. (6mm) thick, note thickness.

Fissured
Slickensided Fracture planes appear polished or glossy, sometimes striated.

DESCRIPTION
Non-Plastic
Low
Dry
Wet
Visible free water,
usually soil is below
water table

FIELD TEST
Absence of
moisture, dusty,
dry to the touch
Sand
Fines

GRAIN SIZE
>12 in. (304.8 mm.)
3 - 12 in. (76.2 - 304.8 mm.)
3/4 -3 in. (19 - 76.2 mm.)

0.19 - 0.75 in. (4.8 - 19 mm.)
#10 - #4 0.079 - 0.19 in. (2 - 4.9 mm.)

APPARENT

DENSITY
30 - 50
10 - 30
4 - 10
Secondary
Constituent is
Coarse Grained
Term
of
Use
<5%
With
Modifier
5 to <15%
Secondary
Constituent is
Fine Grained
15%
Trace <15%
15 to <30%
30%
AMOUNT

CRITERIA
<500

0.5 PP <1
1 PP <2
2 PP <4
4 PP
Pocket Pen
(tsf)
PP < 0.25
Medium Stiff

0.25 PP <0.5

SPT - N
(# blows / ft)
medium

SIEVE SIZE

DESCRIPTION
Damp but no
visible water
#40 - #10

0.0029 - 0.017 in. (0.07 - 0.43 mm.)
Passing #200 <0.0029 in. (<0.07 mm.)

DESCRIPTION
3 - 12 in.
3/4 -3 in.
#4 - 3/4 in.
1,000 - 2,000
2,000 - 4,000
4,000 - 8,000
>8,000
<4
Very Dense
Dense
Medium Dense
>50
Loose
Very Loose
Alternating layers of varying material or color with the layers less than 1/4-in. (6 mm) thick, note thickness. Laminated Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay; note thickness. Lensed Boulders
Cobbles

0.017 - 0.079 in. (0.43 - 2 mm.)
#200 - #40
Cohesive soil that can be broken down into small angular lumps which resist further breakdown. Blocky

CRITERIA
Medium
High

CRITERIA
A 1/8 in. (3 mm) thread cannot be rolled at any water content.

The thread can barely be rolled and the lump cannot be formed when drier than the plastic limit.

The thread is easy to roll and not much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. The lump crumbles when drier than the plastic limit.

It takes considerable time rolling and kneading to reach the plastic limit. The thread can be rerolled several times after reaching the plastic limit. The lump can be formed without crumbling when drier than the plastic limit.
coarse
fine
Moist
Rounded
Subrounded Particles have nearly plane sides but have well-rounded corners and edges.

Angular Particles have sharp edges and relatively plane sides with unpolished surfaces.

Subangular
Particles have smoothly curved sides and no edges.

Particles are similar to angular description but have rounded edges.

DESCRIPTION
None
Weak
Crumbles or breaks
with considerable finger
pressure
Moderately
Weakly
Will not crumble or
break with finger
pressure

DESCRIPTION
Strongly

FIELD TEST
Crumbles or breaks
with handling or little
finger pressure
Readily indented by thumb but penetrated only
with great effort
Easily penetrated several inches by fist
Easily penetrated several inches by thumb
Can be penetrated several inches by thumb with
moderate effort
Readily indented by thumbnail
Indented by thumbnail with difficulty

CONSISTENCY VISUAL / MANUAL CRITERIA
<2
>30
Very Soft
Strong
No visible reaction
Some reaction,
with bubbles
forming slowly
Violent reaction,
with bubbles
forming
immediately

DESCRIPTION FIELD TEST
Soft
Stiff
Very Stiff
Hard
2 - 4
4 - 8
8 - 15
15 - 30

UNCONFINED

COMPRESSIVE
STRENGTH (Qu)(psf)
>12 in.

Stratified
500 - 1,000
STRUCTURE1 ANGULARITY1
GRAIN SIZE1
CONSISTENCY - FINE-GRAINED SOIL2, 3
CEMENTATION1

APPARENT DENSITY -
COARSE-GRAINED SOIL2
PLASTICITY1 MOISTURE CONTENT1

REACTION WITH
HYDROCHLORIC ACID1
SECONDARY CONSTITUENT1

REFERENCES

1. American Society for Materials and Testing (ASTM), 2017, ASTM D2488: Standard Practice for Description and Identification of Soils (Visual Manual Procedures).

2. Terzaghi, K and Peck, R., 1948, Soil Mechanics in Engineering Practice, John Wiley & Sons, New York.

3. United States Department of the Interior Bureau of Reclamation (USBR), 1998, Earth Manual, Part I.
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CHECKED BY: H.M
DRAWN BY: D.E
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PROJECT NO.:

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A-3

ROCK DESCRIPTION KEY FIGURE
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
Slightly Fractured
Moderately Fractured
Highly Fractured

RECOGNITION
Honeycombed
Small openings in volcanic rocks
of variable shape and size formed
by entrapped gas bubbles during
solidification.

Vesicle (Vesicular)
Pit (Pitted)
None
Muscovite
Small openings (usually lined with
crystals) ranging in diameter from

0.03 ft. (3/8 in.) to 0.33 ft. (4 in.)
(10 to 100 mm.)
RQD
Bedding Planes
Fracture in rock, generally more or
less vertical or traverse to bedding.

Planes dividing the individual layers,
beds, or stratigraphy of rocks.

DESCRIPTION Thickness [in (mm)]
>36 (>915)
12 - 36 (305 - 915)
4 - 12 (102 - 305)
1 - 4 (25 - 102)

0.4 - 1 (10 - 25)

0.1 - 0.4 (2.5 - 10)
<0.1 (<2.5)
Extremely Weak
Very Weak
Weak
Medium Strong

0.25 - 1.0

1.0 - 5.0

FIELD TEST
Specimen can only be chipped with a geological hammer.

Specimen requires many blows of geological
hammer to fracture it.

Cannot be scraped or peeled with a pocket knife, specimen can be fractured with a single firm blow of a geological hammer.

Albite
Biotite
Manganese Mn
Unweathered
Entire mass discolored; Alteration
pervading most rock, some slight
weathering pockets; some
minerals may be leached out.

Tight
Open
Wide

DESCRIPTION

0.04 - 0.20 (1 - 5)
>0.20 (>5)
<0.04 (<1)
CRITERIA [in (mm)]
>6 ft. (>1.83 meters)
2 - 6 ft. (0.061 - 1.83 meters)
8 in - 2 ft. (203.20 - 609.60 mm)
Rock-quality designation (RQD) Rough measure of
the degree of jointing or fracture in a rock mass,
measured as a percentage of the drill core in lengths
of 4 in. (10 cm.) or more.
2 - 8 in (50.80 - 203.30 mm)
Joint
Seam
Intensely Fractured

SPACING CRITERIA
<2 in (<50.80 mm)

DESCRIPTION
Unfractured
Applies to bedding plane with
unspecified degree of weather.

Pinhole to 0.03 ft. (3/8 in.) (>1 to
10 mm.) openings
Vug (Vuggy)

DESCRIPTION
An opening larger than 0.33 ft. (4
in.) (100 mm.), size descriptions
are required, and adjectives such
as small, large, etc., may be used
Cavity
If numerous enough that only thin
walls separate individual pits or
vugs, this term further describes
the preceding nomenclature to
indicate cell-like form.

CRITERIA
Discoloring evident; surface pitted
and alteration penetration well
below surface; Weathering "halos"
evident; 10-50% rock altered.

No evidence of chemical /
mechanical alternation; rings with
hammer blow.

Rock reduced to soil with relic
rock texture/structure; Generally
molded and crumbled by hand.

Moderately Weathered
Slightly Weathered

DESCRIPTION
ABBR
Uk
Ta
Si
Ser
Sd
NAME
Very Thick Bedded
Epidote Ep
Ch
Ca
Cl
Ap
Strong
Very Strong
Extremely Strong

5.0 - 25
25 - 50
50 - 100
Iron Oxide Fe
Gypsum Gy
100 - 250
> 250
GRADE
Indented by thumbnail
Apatite
Clay
Calcite
Chlorite
ABBR
Bi
NAME
Unknown
Talc
Silt
Moderately Bedded
Thin Bedded
Laminated
Thinly Laminated
Sericite
Sand
Quartz
Pyrite
Qz
Py
No
Mus
Crumbles under firm blows of geological hammer,
can be peeled by a pocket knife.

Specimen requires more than one blow of geological hammer to fracture it.

Al R0
R1
R2
R3
R4
R5
R6
Poor
Very Poor
RQD (%)
Thick Bedded
Very Thin Bedded
Can be peeled by a pocket knife with difficulty, shallow indentations made by firm blow with point of geological hammer.
0 - 25
25 - 50
50 - 75
75 - 90
90 - 100
Fair
Good
Excellent

DESCRIPTION
Decomposed
Highly Weathered
Slight discoloration on surface;
slight alteration along
discontinuities; <10% rock volume
altered.

CORE SAMPLER

AQ CORE BARREL
(1.067 in. (27.1 mm.) core diameter)

AX CORE BARREL
(1.185 in. (30.1 mm.) core diameter)

BQ CORE BARREL
(1.433 in. (36.4 mm.) core diameter)

CONTINUOUS CORE SAMPLE
(2.000 in. (50.8 mm.) core diameter)

CORE SAMPLER TYPE GRAPHICS

EX CORE BARREL
(0.846 in. (21.5 mm.) core diameter)

HQ CORE SAMPLE
(2.500 in. (63.5 mm.) core diameter)

NQ CORE SAMPLE
(1.874 in. (47.6 mm.) core diameter)

NO RECOVERY CORE SAMPLE

NX CORE SAMPLE
(2.154 in. (54.7 mm.) core diameter)

REFERENCES

1. Bieniawski, Z.T., 1989, Engineering Rock Mass
Classifications. John Wiley & Sons, New York. (Mod. by
Kleinfelder).

2. Deere, D.U., and Deere, D.W., 1989, Rock Quality
Designation (RQD) After Twenty Years, USACE Contract
Report GL-89-1.

3. Federal Highway Administration (FHWA), 2002,
Subsurface Investigations, FHWA-NHI-01-031. (Mod. by
Kleinfelder).

4. International Society for Rock Mechanics (ISRM), 1978, "Suggested Methods for the Quantitative Description of
Discontinuities in Rock Masses," International Joint Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 15. 5. United States Army Corps of Engineers (USACE), 1994, Rock Foundations, EM 1110-1-2908, November 30, 1994.

6. United States Department of the Interior Bureau of
Reclamation (USBR), 1998, Engineering Geology Field
Manual, Volume 1.

UCS (MPa)
4 - 6
6 - 8
2 - 4
8 - 10
10 cm
0 - 2
12 - 14
18 - 20
14 - 16
16 - 18
WEATHERING5
ADDITIONAL TEXTURAL ADJECTIVES5
DENSITY/SPACING OF DISCONTINUITIES5
INFILLING TYPE3
0 5 cm
RELATIVE HARDNESS / STRENGTH DESCRIPTIONS4
ROCK QUALITY DESIGNATION (RQD)2 JOINT ROUGHNESS COEFFICIENT (JRC)4 APERTURE1
BEDDING CHARACTERISTICS6
10 - 12
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [_KLF_GEO_LEG3_ROCK_DESC_KEY] PLOTTED: 02/13/2025 01:47 PM BY: DEdrees DATE:

CHECKED BY: H.M
DRAWN BY: D.E
25003229.001A
PROJECT NO.:

DRAFT
Item: 11
1805
113.8
109.8
Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Silty SAND (SM): fine to medium sand, low
plasticity, brown, moist
light gray, loose
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
light olive gray, decrease in fines
light gray
olive gray
excavates as clayey sand (SC), olive-light
brown, fine to medium sand, low plasticity
18"
18"
10"
10"
2"
10"
3"

9.8 11.6

9.0 8.6
BC=9
9 6
BC=10
12 14
BC=24
50/4"
BC=23
50/4"
BC=50/2"
BC=20
50/4"
BC=50/3"
30 Hand auger 5ft bgs
5 1 of 2

FIELD EXPLORATION
A-1

LABORATORY RESULTS
Lithologic Description
BORING LOG B-1
PAGE:

BORING LOG B-1
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67737°
Longitude: -117.67003°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 PLOTTED: 02/14/2025 11:47 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1806
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, trace
clay, trace subangular gravel, highly
weathered, very weak (R1)
fine to coarse sand
excavates as poorly graded sand with silt
(SP-SM), light gray, fine to medium sand
The boring was terminated at approximately

49.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
6"
4"
6"
12"
BC=50/6"
BC=50/4"
BC=50/6"
BC=32
50/6"
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
2 of 2

FIELD EXPLORATION
A-2

LABORATORY RESULTS
Lithologic Description
BORING LOG B-1
PAGE:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
40 45
50 55
60 65
Elevation (feet)
745
740
735
730
725
720
715
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
8 9
10 11
PLOTTED: 02/14/2025 11:47 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1807
116.7
119.7
21 Asphalt: approximately 4"
Aggregate Base: approximately 4"
Artifical Fill
Clayey SAND (SC): fine to medium sand,
light brown, moist, trace fine anglar gravel
Silty SAND (SM): fine to medium sand,
non-plastic to low plasticity, light gray, moist,
trace clay
medium dense
Clayey SAND (SC): fine to medium sand,
olive gray, moist, trace coarse sand
medium dense
Capistrano Formation
SANDSTONE: excavates as silty clayey sand
(SC-SM), light gray, fine to medium sand,
moist, trace gravel, highly weathered, very
weak (R1)
excavates as silty sand (SM), light gray, fine to
coarse sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
18"
18"
18"
12"

9.4 12.0

14.8 13.1

11.6 BC=5
8 9
BC=10
17 22
BC=8
14 14
BC=8
15 21
BC=26
50/6"
Hand auger 5ft bgs
Corrosion Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-3

LABORATORY RESULTS
Lithologic Description
BORING LOG B-2
PAGE:

BORING LOG B-2
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67753°
Longitude: -117.66967°
Ground Surface Elevation (ft.): 782.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1808
117.8
120.9
Asphalt: approximately 4"
Aggregate Base: approximately 3"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
medium dense
Silty SAND (SM): fine to medium sand, light
gray, moist
non-plastic to low plasticity
medium dense
Capistrano Formation
SANDSTONE: fine to medium sand,
excavates as silty sand (SM), light gray, fine to
coarse sand, moist, highly weathered, very
weak (R1)
olive-light gray, fine to medium sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
18"
18"
18"
9"

11.8 12.0

10.8 10.6
BC=12
18 14
BC=7
10 9
BC=11
17 20
BC=15
26 50
BC=40
50/3"
29 Hand auger 5ft bgs
3 Groundwater was not observed during drilling or after completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-4

LABORATORY RESULTS
Lithologic Description
BORING LOG B-3
PAGE:

BORING LOG B-3
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67768°
Longitude: -117.66928°
Ground Surface Elevation (ft.): 783.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1809
112.2
16 Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist, trace clay, tree branches
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace coarse sand
fine to coarse sand
increase in fines, fine to medium sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
10"
3"
3"
6"
10"

8.1 7.3
BC=19
50/4"
BC=50/3"
BC=50/3"
BC=50/6"
BC=39
50/4"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-5

LABORATORY RESULTS
Lithologic Description
BORING LOG B-4
PAGE:

BORING LOG B-4
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67789°
Longitude: -117.66894°
Ground Surface Elevation (ft.): 784.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1810
125.9
102.6
Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace coarse sand
Silty SAND (SM): fine to medium sand,
non-plastic to low plasticity, olive gray, moist
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as poorly graded sand (SP)
excavates as silty sand (SM)
increase in fines, trace coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
17"
5"
11"
4"

11.0 11.7

13.4 BC=13
21 31
BC=35
35 50/5"
BC=50/5"
BC=31
50/5"
BC=50/4"
25 Hand auger 5ft bgs
3 Groundwater was not observed during drilling or after completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-6

LABORATORY RESULTS
Lithologic Description
BORING LOG B-5
PAGE:

BORING LOG B-5
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67792°
Longitude: -117.66856°
Ground Surface Elevation (ft.): 782.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1811
140.0
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as poorly graded
sand (SP), gray, fine to coarse sand, moist,
highly weathered, very weak (R1)
excavates as silty sand (SM), light gray, fine
to medium sand
excavates as clayey sand (SC), olive gray
excavates as poorly graded sand with silt
(SP-SM), gray
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
3"
9"
5"
9"

13.6 2.0

10.9 BC=6
6 7
BC=50/3"
BC=33
50/3"
BC=50/5"
BC=37
50/3"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-7

LABORATORY RESULTS
Lithologic Description
BORING LOG B-6
PAGE:

BORING LOG B-6
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67768°
Longitude: -117.66864°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1812
123.5
111.4
19 Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, grayish brown, moist, trace gravel
up to 0.75"
Silty SAND (SM): fine to medium sand,
non-plastic, olive gray, moist, trace coarse
sand
dense
light gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine sand, moist, highly weathered,
very weak (R1)
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand
fine to coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
18"
11"
11"
5"

10.9 11.7

12.6 9.4
BC=15
21 25
BC=7
13 27
BC=26
50/5"
BC=29
50/5"
BC=50/5"
NP
Hand auger 5ft bgs
NP
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-8

LABORATORY RESULTS
Lithologic Description
BORING LOG B-7
PAGE:

BORING LOG B-7
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67754°
Longitude: -117.66888°
Ground Surface Elevation (ft.): 780.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1813
120.6
110.4
Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, low plasticity, brown, moist,
angular to subangular gravel up to 0.5"
Silty SAND (SM): fine to medium sand, olive,
moist
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
fine sand, light gray, highly weathered, very
weak (R1)
fine to medium sand
trace coarse sand
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand, subangular
gravel up 0.5"
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
11"
9"
11"
5"

12.8 8.7

7.9 8.0
BC=18
17 23
BC=17
50/5"
BC=45
50/3"
BC=32
50/5"
BC=50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-9

LABORATORY RESULTS
Lithologic Description
BORING LOG B-8
PAGE:

BORING LOG B-8
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67740°
Longitude: -117.66930°
Ground Surface Elevation (ft.): 779.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1814
115.3
107.8
16 Asphalt: approximately 4"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand, olive
brown, moist
olive to light brown, medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
fine sand
excavates as poorly graded sand (SP-SM),
fine to medium sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
9"
10"
4"
6"

10.1 7.9

7.9 6.7
BC=8
9 9
BC=28
50/3"
BC=40
50/4"
BC=50/4"
BC=50/6"
27 Hand auger 5ft bgs
5 Groundwater was not observed during drilling or after completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-10

LABORATORY RESULTS
Lithologic Description
BORING LOG B-9
PAGE:

BORING LOG B-9
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67724°
Longitude: -117.66964°
Ground Surface Elevation (ft.): 778.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1815
126.6
115.6
Asphalt: approximately 4"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand, olive
brown, moist
light gray, dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine sand, moist, highly weathered,
very weak (R1)
fine to medium sand
The boring was terminated at approximately
20 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
11"
9"
11"
2"

10.9 8.6

8.9 7.6
BC=12
19 48
BC=38
50/5"
BC=50/6"
BC=50/6"
BC=50/2"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-11

LABORATORY RESULTS
Lithologic Description
BORING LOG B-10
PAGE:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1816
123.6
108.7
17 Asphalt: approximately 4"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
non-plastic to low plasticity, brown, moist,
trace subrounded gravel
Silty SAND (SM): fine to medium sand, olive
gray, moist, trace clay
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
gray, decrease in fines
excavates as poorly graded sand (SP)
olive gray
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
11"
5"
3"
5"

12.1 12.4

9.2 9.3
BC=20
15 22
BC=28
50/5"
BC=50/5"
BC=50/3"
BC=50/5"
Hand auger 5ft bgs
Corrosion Test
Modified Proctor
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-12

LABORATORY RESULTS
Lithologic Description
BORING LOG B-11
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1817
124.0
108.7
Asphalt: approximately 2.5"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist
gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as poorly graded sand with silt
(SP-SM)
excavates as silty sand (SM)
increase in sand, trace coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
11"
6"
6"
4"

13.0 9.9

9.8 8.7
BC=8
16 33
BC=33
50/5"
BC=50/6"
BC=50/6"
BC=50/4"
NP
Hand auger 5ft bgs
NP
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-13

LABORATORY RESULTS
Lithologic Description
BORING LOG B-12
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1818
123.8
Asphalt: approximately 3.5"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace subangular gravel up to

10.3 9.7

8.2 BC=8
18 40
BC=50/5"
BC=37
50/1"
BC=26
50/3"
BC=25
50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-14

LABORATORY RESULTS
Lithologic Description
BORING LOG B-13
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1819
121.4
116.8
15 Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
olive gray, medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
decrease in fines
excavates as silty clayey sand (SC-SM),
non-plastic to low plasticity
excavates as silty sand (SM)
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
12"
3"
3"
6"

13.9 13.5

7.8 4.3
BC=4
5 9
BC=13
50/6"
BC=50/3"
BC=50/3"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-15

LABORATORY RESULTS
Lithologic Description
BORING LOG B-14
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1820
121.3
116.3
Asphalt: approximately 2.5"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist
olive gray, medium dense, increase in fines
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as pooly graded sand with silt
(SP-SM), light gray
excavates as pooly graded sand (SP)
excavates as silty sand (SM)
excavates as pooly graded sand with silt
(SP-SM), light gray
18"
6"
6"
10"
4"
3"
6"

12.4 7.9

9.8 10.8
BC=25
18 19
BC=50/6"
BC=50/6"
BC=30
50/4"
BC=50/4"
BC=50/3"
BC=50/6"
NP
Hand auger 5ft bgs
NP
1 of 2

FIELD EXPLORATION
A-16

LABORATORY RESULTS
Lithologic Description
BORING LOG B-15
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1821
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as silty sand (SM), fine sand
excavates as pooly graded sand (SP), light
gray
The boring was terminated at approximately
49 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
6"
4"
6"
4"
BC=50/6"
BC=50/4"
BC=50/6"
BC=50/4"
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
2 of 2

FIELD EXPLORATION
A-17

LABORATORY RESULTS
Lithologic Description
BORING LOG B-15
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1822
125.1
115.7
14 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Silty SAND (SM): fine to medium sand, olive
gray, moist, trace clay
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist. highly
weathered, very weak (R1)
decrease in fines
excavates as poorly graded sand with silt
(SP-SM)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
12"
6"

10.1 11.0

9.0 8.9
BC=10
20 36
BC=32
50/6"
BC=50/6"
Hand auger 5ft bgs
Corrosion Test
Modified Proctor
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-18

LABORATORY RESULTS
Lithologic Description
BORING LOG B-16
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1823
122.6
109.0
22 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, brown, moist, angular to
subangular gravel up to 0.5"
Capistrano Formation
SANDSTONE: excavates as sity sand (SM),
light gray, fine to medium sand, highly
weathered, very weak (R1)
trace clay
excavates as clayey sand (SC), low plasticity
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
17"
16"
6"

13.6 10.3

19.7 BC=10
36 50/5"
BC=25
36 50/4"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-19

LABORATORY RESULTS
Lithologic Description
BORING LOG B-17
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1824
114.7
Asphalt: approximately 3.5"
Aggregate Base: approximately 4"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist
Silty SAND (SM): fine to coarse sand, gray,
moist
fine to medium sand
Capistrano Formation
SANDSTONE: excavates as poorly graded
sand (SP-SM), light gray, fine to medium
sand, highly weathered, very weak (R1)
excavates as sity sand (SM)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
6"
6"

11.7 9.3

9.1 BC=16
24 44
BC=50/6"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-20

LABORATORY RESULTS
Lithologic Description
BORING LOG B-18
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1825
121.9
Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Silty Clayey SAND (SC-SM): fine to medium
sand, brown, moist, trace angular fine gravel
Silty SAND (SM): fine sand, light gray, moist
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
6"
12"

12.9 10.8

10.6 BC=7
14 23
BC=50/6"
BC=31
50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-21

LABORATORY RESULTS
Lithologic Description
BORING LOG B-19
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1826
122.0
22 Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, olive gray, moist
Silty SAND (SM): fine to medium sand, olive
gray, moist
Capistrano Formation
SANDSTONE (SM): light gray, moist,
excavates as silty sand (SM), light gray, fine to
coarse sand, highly weathered, very weak
(R1)
excavates as poorly graded sand (SP)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
6"
5"

9.6 16.3

10.6 8.7
BC=4
5 15
BC=50/6"
BC=50/5"
30 Hand auger 5ft bgs
8 R-Value Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-22

LABORATORY RESULTS
Lithologic Description
BORING LOG B-20
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1827
18 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as clayey sand
(SC), light gray, fine to medium sand, moist,
highly weathered, very weak (R1)
excavates as silty sand (SM), olive
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
1"
NR
11"

9.8 8.9
BC=50/1"
BC=50/1"
BC=24
50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-23

LABORATORY RESULTS
Lithologic Description
BORING LOG B-21
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1828
121.4
117.9
17 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, trace
clay, highly weathered, very weak (R1)
increase in fines, fine sand
excavates as clayey sand (SC), light gray, fine
sand, low plasticity
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
12"
9"
3"

13.0 9.8

10.2 BC=17
50/6"
BC=24
50/3"
BC=50/3"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-24

LABORATORY RESULTS
Lithologic Description
BORING LOG B-22
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1829
123.3
Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace fine subrounded gravel
Capistrano Formation
SANDSTONE: excavates as silty sad (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace clay
olive gray
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
12"
16"
2"

11.7 12.6

10.6 7.3
BC=16
50/6"
BC=40
37 50/4"
BC=50/6"
31 Hand auger 5ft bgs
11 R-Value Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-25

LABORATORY RESULTS
Lithologic Description
BORING LOG B-23
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1830
116.8
17 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
dark brown, moist, trace fine gravel
Capistrano Formation
SANDSTONE: excavates silty sand (SM),
light gray, fine to medum sand, moist, highly
weathered, very weak (R1)
decrease in fines
increase in fines, fine sand
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
6"
14"

10.9 10.4

9.4 BC=13
30 40
BC=50/6"
BC=30
38 50/2"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-26

LABORATORY RESULTS
Lithologic Description
BORING LOG B-24
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1831
122.8
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace fine gravel
Capistrano Formation
SANDSTONE: excavates silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace coarse sand
decrease in fines
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
6"
8"
1"

12.7 10.7

4.3 BC=50/6"
BC=25
50/2"
BC=50/1"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-27

LABORATORY RESULTS
Lithologic Description
BORING LOG B-25
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1832
118.9
25 Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, light gray, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, higly
weatheres, very weak (R1)
decrease in fines
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
4"
8"
6"

10.6 10.5

8.8 BC=50/4"
BC=27
50/2"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-28

LABORATORY RESULTS
Lithologic Description
BORING LOG B-26
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1833
124.4
117.8
114.9
Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND with Gravel (SM): fine to medium
sand, brown, moist
Capistrano Formation
SANDSTONE: excavaes as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
increase in fines
fine sand
decrease in fines
increase in fines
excavates as poorly graded sand with silt
(SP-SM)
excavates as poorly graded sand (SP), fine
sand
excavates as silty sand (SM)
The boring was terminated at approximately
26 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
9"
12"
6"
12"
6"
6"
5"
11"

10.0 9.6

9.7 12.8

11.2 BC=25
50/3"
BC=23
50/6"
BC=50/6"
BC=14
50/6"
BC=50/6"
BC=50/6"
BC=50/5"
BC=31
50/5"
NP
Hand auger 5ft bgs
NP Corrosion Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-29

LABORATORY RESULTS
Lithologic Description
BORING LOG B-27
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 8
9 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1834
114.1
113.5
112.6
22 Asphalt: approximately 3.5"
Aggregate Base: approximately 4"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, brown, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
yellow, fine to medium sand, moist, highly
weathered, very weak (R1)
decrease in fines
excavates as clayey sand (SC), gray, fine
sand, low to medium plasticity
excavates as silty sand (SM), light gray, fine to
medium sand, trace clay
fine to coarse sand, decrease in fines
fine to medium sand
decrease in fines
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand
excavates as poorly graded sand (SP), fine to
coarse sand
The boring was terminated at approximately
25 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
10"
5"
9"
6"
12"
6"
11"
2"

8.8 11.0

9.6 7.6

8.2 BC=34
50/4"
BC=50/5"
BC=34
50/3"
BC=50/6"
BC=27
50/6"
BC=50/6"
BC=25
50/5"
BC=50/2"
Hand auger 5ft bgs
Direct Shear Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-30

LABORATORY RESULTS
Lithologic Description
BORING LOG B-28
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 8
PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1835
97 19
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Silty Clayey SAND (SC-SM): fine to medium
sand, brown, moist
The boring was terminated at approximately 5
ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.

Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-31

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-1
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1836
100 20
Asphalt: approximately 5"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace angular gavel
light gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
gray, fine to medium sand, moist, trace clay,
highly weathered, very weak (R1)
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
11"
BC=8
14 12
BC=39
50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-32

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-2
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1837
99 15
Asphalt: approximately 5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist
olive
The boring was terminated at approximately 5
ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.

Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-33

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-3
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1838
100 7.5
Asphalt: approximatey 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace angular gravel
ollive gray
Capistrano Formation
SANDSTONE: excavates as well graded
sand with silt (SW-SM), olive gray, fine to
medium sand, moist highly weathered, very
weak (R1)
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
18"
BC=7
10 12
BC=18
34 50
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-34

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-4
PAGE:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
DRAFT
Item: 11
1839
25003229.001A/LH25R178197 February 14, 2025
© 2025 Kleinfelder www.kleinfelder.com

APPENDIX B

LABORATORY TESTING
DRAFT
Item: 11
1840
25003229.001A/LH25R178197 Page B-1 February 14, 2025
© 2025 Kleinfelder www.kleinfelder.com

APPENDIX B

LABORATORY TESTING

DRAFT
Item: 11
1842
SYMBOL
1 GRAVEL

3.5 0.0

1.2 SAMPLE
NO.

SAMPLE IDENTIFICATION
BORING
NO.

INF-1
INF-2
INF-3

4.5-5

8.5 4.5-5

PERCENTAGES
1 2
NM
DEPTH
(ft.) FINES

18.6 20.3

15.3 SAND

77.9 79.7

83.5 NM

SOIL CLASSIFICATION
Silty Sand (SM)
Silty Sand (SM)
Silty Sand (SM)
PI

ATTERBERG LIMITS
LL
NM NM
NM
NM
PL
NM
NM NM
INF-4 2 8.5 0.0 92.5 7.5 NM NM NM Well Graded Sand with Silt (SW) 0 10
20 30
40 50
60 70
80 90
100
100.000 10.000 1.000 0.100 0.010 0.001

CUMULATIVE PERCENT PASSING

GRAIN SIZE IN MILLIMETERS

SILT CLAY

COBBLE GRAVEL SAND SILT CLAY

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Well Graded Sand with Silt (SW-SM) Silty Clayey Sand (SC-SM) Clayey Sand (SC) Silty Sand (SM) Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
DRAFT
Item: 11
1843
Testing performed in general accordance with ASTM D4318 1 1
5 5

7.5 Silty Sand (SM)
Silty Sand (SM)
SYMBOL
25 22 3

N/A N/A N/A
27 22 5
5 B-5 1
B-1 1
B-3 2
B-7
B-9

SOIL CLASSIFICATION

SAMPLE IDENTIFICATION
Silty Sand (SM)
Silty Sand (SM)
30 25 5
29 26 3

ATTERBERG LIMITS

LL PL PI BORING
NO.

SAMPLE
NO. DEPTH (ft)
5 Silty Sand (SM)
MH or OH
ML or OL
CH or OH
CL-ML
CL or OL
0 10
20 30
40 50
60 0 10 20 30 40 50 60 70 80 90 100 110

PLASTICITY INDEX (PI)

LIQUID LIMIT (LL)
PROJECT NO.:

TESTED BY:

DATE:

CHECKED BY:

DATE:

NP NP NP
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
DRAFT
Item: 11
1844
Testing performed in general accordance with ASTM D4318

SOIL CLASSIFICATION

SAMPLE IDENTIFICATION
Silty Sand (SM)
Silty Sand (SM)

N/A N/A N/A

ATTERBERG LIMITS

LL PL PI BORING
NO.

SAMPLE
NO. DEPTH (ft)
0-5 Silty Sand with Gravel (SM)
SYMBOL
30 22 8
31 20 11

N/A N/A N/A
0-5
B-20 1
B-12 1
B-15 1
B-23
B-27
0-5
5 5
Clayey Sand (SC)
Clayey Sand (SC)
1 1
MH or OH
ML or OL
CH or OH
CL-ML
CL or OL
0 10
20 30
40 50
60 0 10 20 30 40 50 60 70 80 90 100 110

PLASTICITY INDEX (PI)

NPNPNP NPNPNP NPNPNP
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
DRAFT
Item: 11
1845
Project Name: Costco Foothill Ranch, CA GEO Tested By: ST Date: 01/27/25 Project No.: 25003229.001A Computed By: JP Date: 02/03/25 Boring No.: B‐28 Checked by: AP Date: 02/03/25
Sample No.: 4 Depth (ft): 12.5
Sample Type: Mod. Cal.

DRAFT
Item: 11
1846
Boring No.: B-11
Sample No.: 1
Depth: 0-5
Material Description: Clayey Sand (SC)
Maximum Dry Unit Weight (pcf)
Optimum Water Content (%)
Oversize Fraction, retained on 3/8 (%)
Tested in accordance with: ASTM D1557, Method B
na
<5
Bulk Specific Gravity of Oversize Fraction na

DATE:

CHECKED BY:

DATE:

PROJECT NO.:
100
110
120
130
140

0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Unit Weight (pcf)
Water Content (%)

2.75 2.70

2.65 2.60
Compaction Curve
Compaction Curve, Corrected
KLEINFELDER - 620 South Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
DRAFT
Item: 11
1847
Boring No.: B-16
Sample No.: 1
Depth: 0-5
Material Description: Clayey Sand (SC)
Maximum Dry Unit Weight (pcf)
Optimum Water Content (%)
Oversize Fraction, retained on 3/8 (%)
Tested in accordance with: ASTM D1557, Method B
na
<5
Bulk Specific Gravity of Oversize Fraction na

DATE:

CHECKED BY:

DATE:

PROJECT NO.:
100
110
120
130
140

0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Unit Weight (pcf)
Water Content (%)

2.75 2.70

Sample No.:

Depth:

Material Description:

Test Procedure: ASTM D2844
Specimen No. B
Moisture at Test (%)
Dry Unit Weight at Test (pcf)
Expansion Pressure (psf)
19 15

21.6 568.4
A

10.2 123.6

0.0 792.0
B-20
Exudation Pressure (psi)
Resistance Value
R - VALUE AT 300 PSI EXUDATION PRESSURE
1 10.6
Clayey Sand (SC)
C
119.3

11.5 123.0
0-5

26.0 212.4
1430
0 10
20 30
40 50
60 70
80 90
100
050100150200250300350400450500550600650700750800
R-Value
Exudation Pressure (psi)

R-VALUE
Proposed Costco Wholesale Warehouse and Fuel
Facility
26602 Towne Centre Drive
Foothill Ranch, California 2/11/2025
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
DRAFT
Item: 11
1849
Boring No.:

Sample No.:

Depth:

Material Description:

Test Procedure: ASTM D2844
Specimen No. B
Moisture at Test (%)
Dry Unit Weight at Test (pcf)
Expansion Pressure (psf)
18 16

21.6 543.2
A

11.6 118.3

0.0 260.0
B-23
Exudation Pressure (psi)
Resistance Value
R - VALUE AT 300 PSI EXUDATION PRESSURE
1 11.1
Clayey Sand (SC)
C
119.1

10.6 119.6
0-5

26.0 641.2
2016
0 10
20 30
40 50
60 70
80 90
100
050100150200250300350400450500550600650700750800
R-Value
Exudation Pressure (psi)

R-VALUE
Proposed Costco Wholesale Warehouse and Fuel
Facility
26602 Towne Centre Drive
Foothill Ranch, California 2/11/2025
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
DRAFT
Item: 11
1850

NOTES: Resistivity Test and pH: California Test Method 643 Sulfate Content : California Test Method 417
Chloride Content : California Test Method 422
ND = Not Detectable
NA = Not Sufficient Sample
NR = Not Requested
Minimum
(ohm-cm)
2,767
Resistivity
3,147
1,907
2,048
DRAFT
Item: 11
1851
25003229.001A/LH25R178197 February 14, 2025
© 2025 Kleinfelder www.kleinfelder.com

APPENDIX C

INFILTRATION TEST RESULTS
DRAFT
Item: 11
1852
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

2.0 5.0

1.8 2
8 Boring Percolation Test Method Figure
25003229.001A
Proposed Costco Wholesale Warehouse and Fuel Facility
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):
26602 Towne Centre Drive
Foothill Ranch, California
Project No.:

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
DRAFT
Item: 11
1853
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

5.0 10.0

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
DRAFT
Item: 11
1854
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

2.0 5.1

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
DRAFT
Item: 11
1855
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

5.0 10.1

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
DRAFT
Item: 11
1856
Priority Project Water Quality Management Plan (WQMP)
Costco Foothill Ranch
COSTCO WHOLESALE Section VII
Costco Foothill Ranch WQMP November 2025 Page 33
Attachment F – Educational Materials
To be prepared in Final Engineering.

Item: 11
1857
Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix H
Appendix H – Noise Impact Study

Item: 11
1858
Environmental Noise Impact Study

COSTCO WHOLESALE WAREHOUSE PROJECT

FOOTHILL RANCH, CALIFORNIA
Prepared for:

Costco Wholesale
January 2026
Report Ref:

R2025121.1

Prepared by:

Acoustical Engineering Services, Inc.
515 South Flower Street, 18th Floor
Los Angeles, CA 90071
Item: 11
1859
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study

Acoustical Engineering Services, Inc. January 2026
Table of Content
Executive summary ................................................................................................................... 1 Findings ..................................................................................................................................... 1 1 Introduction ................................................................................................................... 4

1.1 Project Description ......................................................................................................... 4 2 Environmental Setting .................................................................................................. 5

2.1 Fundamentals of Sound and Environmental Noise ........................................................ 5

2.1.1 Outdoor Sound Propagation ..................................................................................... 5

2.1.2 Environmental Noise Descriptors ............................................................................ 7

2.2 Ground-borne Vibration ................................................................................................. 8

2.3 Applicable Noise Standards ........................................................................................... 9

2.3.1 City of Lake Forest General Plan ............................................................................. 9

2.3.2 City of Lake Forest Municipal Code ...................................................................... 12

2.4 Applicable Vibration Standards.................................................................................... 15

2.5 Existing Ambient Noise Levels .................................................................................... 17 3 Impact Analysis .......................................................................................................... 20

3.1 Methodology................................................................................................................. 20

3.1.1 Construction Noise ................................................................................................. 20

3.1.2 Construction Vibration ........................................................................................... 20

3.1.3 Operational Noise .................................................................................................. 20

3.2 Significance Thresholds ............................................................................................... 21

3.2.1 Construction Noise ................................................................................................. 22

3.2.2 Construction Vibration ........................................................................................... 22

3.2.3 Operations Noise .................................................................................................... 22

3.3 Construction Noise Impacts ......................................................................................... 23

3.4 Construction Vibration Impacts.................................................................................... 27

3.5 Operation Impacts ........................................................................................................ 29

3.5.1 Mechanical ............................................................................................................. 29

3.5.2 Loading Dock Operation ........................................................................................ 29

3.5.3 Warehouse Delivery Trucks ................................................................................... 30

3.5.4 Trash Compactors .................................................................................................. 32

3.5.5 Parking Lot Operation ............................................................................................ 32

3.5.6 Parking Lot Cleaning ............................................................................................. 33

3.5.7 Tire Installation Center .......................................................................................... 34

3.5.8 Composite On-Site Operational Noise Levels ....................................................... 34

3.5.9 Off-Site Traffic ...................................................................................................... 37 4 Mitigation Measures ................................................................................................... 40

4.1 Construction Noise ....................................................................................................... 40

4.2 Construction Vibration ................................................................................................. 40

4.3 Operational Noise ......................................................................................................... 40

Item: 11
1860
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study

Acoustical Engineering Services, Inc. January 2026
List of Figures
Figure 1. Project Site Map ..................................................................................................................... 6 Figure 2. Noise Receptor Locations .................................................................................................... 18

List of Tables
Table 1. Typical Noise Levels ............................................................................................................... 7 Table 2. City of Lake Forest Land Use Compatibility for Community Noise Environment .............. 10 Table 3. City of Lake Forest Exterior Noise Standards ....................................................................... 13 Table 4. City of Lake Forest Vibration Assessment Guidelines ......................................................... 15 Table 5. FTA Construction Vibration Impact Criteria for Building Damage ..................................... 16 Table 6. FTA Construction Vibration Impact Criteria for Human Annoyance ................................... 16 Table 7. Description of Noise Receptor Locations .............................................................................. 17 Table 8. Existing Ambient Noise Levels ............................................................................................. 19 Table 9. Typical Construction Equipment Noise Emission Levels and Usage Factors ...................... 24 Table 10. On-Site Construction Noise Impacts ................................................................................... 26 Table 11. On-Site Construction Noise Impacts – Over lapping Construction .................................... 26 Table 12. Construction Equipment Vibration Levels .......................................................................... 27 Table 13. Construction Vibration Impacts – Building Damage .......................................................... 28 Table 14. Construction Vibration Impacts – Human Annoyance ........................................................ 28 Table 15. Mechanical Noise Levels .................................................................................................... 29 Table 16. Loading Dock Operation Noise Levels ............................................................................... 30 Table 17. Warehouse Delivery Truck Noise Levels ............................................................................ 31 Table 18. Trash compactors Operation Noise Levels .......................................................................... 32 Table 19. Parking Lot Operation Noise Levels ................................................................................... 33 Table 20. Parking Lot Cleaning Noise Levels ..................................................................................... 33 Table 21. Tire Installation Center Noise Levels .................................................................................. 34 Table 22. Composite On-Site Operational Noise Impacts – Daytime Hours ...................................... 36 Table 23. Composite On-Site Operational Noise Impacts – Nighttime Hours .................................... 36 Table 24. Off-Site Traffic Noise Impacts ............................................................................................ 39 Appendices
Appendix A: Ambient Noise Measurements
Appendix B: Construction Noise and Vibration Calculations Worksheets Appendix C: Operation Noise Calculations Worksheets
Item: 11
1861
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

Page 1 ends

Lake Forest City CouncilMarch 17, 2026

Lake Forest City Council
March 17, 2026