2025-01648 Accepting SAFCA’s Urban Level of Flood Protection Reports (LR25-006) Part 1 — Sacramento City Council, October 21, 2025 (part 2 of 8)

July 22, 202
Completion Report AT&T Duct Bank
compaction (ASTM-695). AECOM representative Ed Titus, a certified engineering geologist, monitored North Star’s construction activities regarding limit and depths of excavation, lift placement and compaction, benching into the existing levee embankment, and trimming of the final slope to meet design grades. The contractor completed the earth work excavation and levee rebuild on 14 June 2024 and followed up with hydroseeding on 17 June 2024 at the repaired area. Attachment B also includes photos during construction. As noted, work began on 10 June 2024 and was completed on 17 June 2024.

Blackburn Consultants provided quality control (QC) testing to verify fill material properties (Atterberg limits, grain size distribution) and insitu and laboratory compaction test. AECOM observed QC testing performed by Blackburn and reviewed the results. Based upon these observations and review, it was determined that no additional quality assurance (QA) testing was required. Attachment C presents the results of Blackburn’s QC testing.

After trimming of the finished backfill slope, the disturbed areas were hydroseeded in accordance with the project requirements.

Based upon our monitoring of the construction process and review of the Blackburn QC test results, it is AECOM’s opinion that the work was competed in accordance with AECOM’s plans and with the geotechnical requirements for low permeability material selection and placement. The remediation should alleviate any concerns for through seepage along the duct bank for the design water surface elevation.

Sincerely,
Richard A. Millet, PE, GE
Senior Geotechnical Engineer
AECOM, Inc.

Enclosed:

Attachment A: Figures 1 and 2
Attachment B: Construction Photos
Attachment C: Blackburn Activity Logs and QC Results

Page 2 ends

July 22, 202
Completion Report AT&T Duct Bank
Attachment A
Figures 1 and 2
VOL 2 - NAS LEVEE IMPROVEMENT PLANS
STA 4067+60

PLAN AND PROFILE ARS LEVEE
C-01 1

NORTH AREA STREAMS LEVEE IMPROVEMENT PROJECT
ARCADE CREEK SOUTH LEVEE STATION 4067+60
RICHA RD A. MILLET REGISTEREDPROFESSIONALENGINE R
STATEO
C
F
IC
VA

ILLIFORNIA
No. C33875

PLAN VIEW
VOL 2 - NAS LEVEE IMPROVEMENT PLANS

DETAILS
C-02 2
0 NORTH AREA STREAMS LEVEE IMPROVEMENT PROJECT
ARCADE CREEK SOUTH LEVEE STATION 4067+60
RICHA RD A. MILLET REGISTEREDPROFESSIONALENGINE R
STATEO
C
F
IC
VA

ILLIFORNIA
No. C33875

AT&T DUCT BANK PROFILE
50 40 30 20 10 -10 -20
STEP 1 STEP 2

TOE CUTOFF WALL AT CENTER LINE

BENCHING DETAIL

WASTE STOCKPILE YARD

BORROW AREA LOCATION MAP

SAMPLING LOCATIONS
STAGING/STOCKPILE AREA (SEE AECOM MEMO 7 FEB. 2024)
70 60
30 35
40 45
25 20
15 ℄
℄
℄
℄
July 22, 202
Completion Report AT&T Duct Bank
Attachment B
Construction Photos
July 22, 202
Completion Report AT&T Duct Bank
Project Site Marking and Delineation
Excavation Of Project Site
July 22, 202
Completion Report AT&T Duct Bank
Completed Project Site Excavation
Placement of Title 23 Fill
July 22, 202
Completion Report AT&T Duct Bank
Compaction of Title 23 Fill Replacement
Blackburn QC Testing of Replacement Fill
July 22, 202
Completion Report AT&T Duct Bank
Project Area Levee Rebuild Completed
Project Area Levee Rebuild Completed
July 22, 202
Completion Report AT&T Duct Bank
Hydroseeding of the Project
July 22, 202
Completion Report AT&T Duct Bank
Attachment C
Blackburn Activity Logs and QC Results

SUBMITTAL TRANSMITTAL
From: Date: 6/18/24
North Star Construction & Engineering, Inc.
1282 Stabler Lane #630-109
Yuba City, CA 95993
Contract Number: SAFCA JOC-014
JO-014.03.00
Submittal Number: 05
Specification Section: 01 00 00
To:

CMID
9700 Goethe Road, Suite #D
Sacramento, CA 95827
Attention: John Engle
We are sending you X attached under separate cover
the following items:

X Specification Change Order X Plan Copy of Letter
Substitution Request Shop Drawing Sample X Test Report
Updated Schedule 3 Week Look Ahead
Item No. Copies Description
01 E Compaction Reports
These are transmitted as checked below:

X For Approval
For Your Use
As Requested
For Review and Comment
Remarks:

We verify by signature below that this submittal has been reviewed in detail by us and find the material or equipment referenced meets all of the requirements of the Contract Documents including coordination with all related work, specified or not, (Check line A or B as applicable ending).

Line A X and referenced items are submitted with no exceptions to the Contract Documents.

Line B except for the attached deviations from the Contract Documents Submitted by: Rudy Rodriguez Date: 6/18/24
Site Visit
Date: 06/11/2024
Submitted By: Chavez, Emilio
Area: Soil
Category: Sampling
Sub Category: Soil Sampling
Contractor's Equipment: Cat 420GC excavator, Water Truck Frequency: Periodic
Determination: As Specified
Activity Summary
I arrived on site @ 10:30 a.m. to collect soil sample from the borrow site located at Echo Water Facility in Elk Grove.

North Star crew used a Cat 420GC to excavate and mix the borrow material. A water truck was used to moisture condition the borrow material. I collected a sample from the stockpile and delivered it to our West Sacramento laboratory for Quality Control testing.

This report presents our Field rep’s opinions. The inspection services performed by Blackburn involved the checking and testing of the contractor’s work with respect to the project/DSA approved document; including, as necessary, interpretations of the tests to permit the inspector to render a professional opinion about the contractor’s work. In no event is Blackburn or any of its personnel responsible for accepting or rejecting work performed by the constructor. Blackburn provided reports of its inspections to specified parties. Only the Owner or the Owner’s designated representative(s) had the authority to reject or accept work. Under no circumstance did Blackburn have the authority to stop work. Neither Blackburn nor any of its employees or agents had any responsibility for the means, methods, techniques, operations, or sequencing of construction. Blackburn is not responsible for job site safety. cc: project architect, structural engineer, project inspector, school district Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 1 of 4 ends

North Star crew used a water truck to
moisture conditioned the borrow
material.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 2 of 4 ends

Photo Comments:

North Star crew used a Cat 320GC
excavator to excavate and mix the
borrow material.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 3 of 4 ends

Site Visit
Date: 06/12/2024
Submitted By: Chavez, Emilio
Area: Field Density
Category: Levee
Sub Category: Embankment
Contractor's Equipment:

Cat 315 excavator, Cat CP34 compactor, Multiquip Mikasa MTX70 rammer, water buffalo
Frequency: Continuous
Determination: As Specified
Activity Summary
I arrived on site @ 8:00 a.m. for observation and nuclear density compaction testing on borrow material being placed and compacted along the AT&T duct bank penetration of the Arcade Creek south levee embankment. I met with Ed Titus w/ AECOM (QA Inspector) and Iqbal Basri w/ North Star Construction (Owner).

The crew used the Cat 315 excavator to place and spread the borrow material along the levee embankment in lifts of ~6" thickness.

The excavator was also used to scarify each lift prior to placing additional lifts. The crew used a CP34 compactor to achieve compaction and also used a Multiquip Mikasa MTX70 to compact along the edges of the fill area. The crew placed a total of 9 lifts during this shift. I performed a total of 9 nuclear density compaction tests during this shift. All tests performed, during this shift, achieved the minimum required 97% relative compaction with moisture content within +/2% of optimum, per project specifications.

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 1 of 6 ends

compaction and also used a Multiquip Mikasa MTX70 to compact along the edges of the fill area. The crew placed a total of 9 lifts during this shift. I performed a total of 9 nuclear density compaction tests during this shift. All tests performed, during this shift, achieved the minimum required 97% relative compaction with moisture content within +/2% of optimum, per project specifications.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 2 of 6 ends

Photo Comments:

Levee Embankment prepared for
placement of borrow material fill.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 3 of 6 ends

Photo Comments:

Cat 315 excavator scarifying surface
prior to placing additional lift.

Multiquip Mikasa MTX70 rammer
was used to compact along the
edges of the fill area.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 4 of 6 ends

Photo Comments:

Cat CP34 compacting first lift along
toe of fill area.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 5 of 6 ends

Test Results
Test #
Retest
Of Test Date Proctor ID Method
Soil
Classification
Optimum
Moisture
(%)
Maximum
Dry Density
(pcf)
In Place
Moisture
(%)
In Place
Dry
Density
(pcf)
In Place
Wet
Density
(pcf)
Probe
Depth
(in)
Percent
Compaction
Min Comp.
(%)
Optimum
Moisture
Tolerance
(%) Remark
1 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.0 107.4 126.7 6 99 97 -2 / 2 DP/MP
2 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.1 108.3 127.9 6 100 97 -2 / 2 DP/MP
3 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.6 109.4 129.8 6 101 97 -2 / 2 DP/MP
4 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.5 106.5 126.2 6 98 97 -2 / 2 DP/MP
5 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.5 108.4 128.5 6 100 97 -2 / 2 DP/MP
6 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 17.6 108.2 127.3 6 100 97 -2 / 2 DP/MP
7 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.0 106.6 125.8 6 98 97 -2 / 2 DP/MP
8 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 18.0 108.6 128.1 6 100 97 -2 / 2 DP/MP
Test Information
Test # Test Location Elevation Reference
Gauge
Make / Model / SN / Calibrated Field Technician
1 Levee Embankment: ~Sta. 67+65 (1st Lift) 34.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 2 Levee Embankment: ~Sta. 67+45 (2nd Lift) 34.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 3 Levee Embankment: ~Sta. 67+75 (3rd Lift) 35.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 4 Levee Embankment: ~Sta. 67+70 (4th Lift) 35.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 5 Levee Embankment: ~Sta. 67+40 (5th Lift) 36.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 6 Levee Embankment: ~Sta. 67+65 (6th Lift) 36.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 7 Levee Embankment: ~Sta. 67+75 (7th Lift) 37.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 8 Levee Embankment: ~Sta. 67+55 (8th Lift) 37.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio Remarks
DP/MP: Density Pass / Moisture Pass
Comments
Tests are "Direct Transmission" (Method A) unless probe depth is noted as "Backscatter". Gauge calibration data on file with the testing agency.

Page 1 of 2 ends

Soil Nuclear Gauge
Test Method: ASTM D 6938
Report Date: 06/18/2024
Client:

North Star Construction & Engineering, Inc.

Yuba City, CA 95993
Attn: Zach Milner - PE
Project:

SAFCA ATT Duct Bank
4537.x 003
Sacramento, CA
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION
4067+60
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 916-375-8706
West Sacramento
Test Results
Test #
Retest
Of Test Date Proctor ID Method
Soil
Classification
Optimum
Moisture
(%)
Maximum
Dry Density
(pcf)
In Place
Moisture
(%)
In Place
Dry
Density
(pcf)
In Place
Wet
Density
(pcf)
Probe
Depth
(in)
Percent
Compaction
Min Comp.
(%)
Optimum
Moisture
Tolerance
(%) Remark
9 06/12/24 1778
(BC#3766)
B CL 18.0 108.4 17.7 109.5 128.9 6 101 97 -2 / 2 DP/MP
Test Information
Test # Test Location Elevation Reference
Gauge
Make / Model / SN / Calibrated Field Technician
9 Levee Embankment: ~Sta. 67+70 (9th Lift) 38.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio Remarks
DP/MP: Density Pass / Moisture Pass
Comments
Tests are "Direct Transmission" (Method A) unless probe depth is noted as "Backscatter". Gauge calibration data on file with the testing agency.

Page 2 of 2 ends

Soil Nuclear Gauge
Test Method: ASTM D 6938
Report Date: 06/18/2024
Client:

North Star Construction & Engineering, Inc.

Yuba City, CA 95993
Attn: Zach Milner - PE
Project:

SAFCA ATT Duct Bank
4537.x 003
Sacramento, CA
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION
4067+60
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 916-375-8706
West Sacramento
Site Visit
Date: 06/13/2024
Submitted By: Chavez, Emilio
Area: Field Density
Category: Levee
Sub Category: Embankment
Contractor's Equipment:

The continued using the Cat 315 excavator to place and spread the borrow material along the levee embankment in lifts of ~6" thickness. The excavator was also used to scarify each lift prior to placing additional lifts. The crew used a CP34 compactor to achieve compaction and also used a Multiquip Mikasa MTX70 to compact along the edges of the fill area. The crew placed a total of 10 lifts during this shift. I performed a total of 10 nuclear density compaction tests during this shift. All tests performed, during this shift, achieved the minimum required 97% relative compaction with moisture content within +/2% of optimum, per project specifications.

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 1 of 3 ends

compaction and also used a Multiquip Mikasa MTX70 to compact along the edges of the fill area. The crew placed a total of 10 lifts during this shift. I performed a total of 10 nuclear density compaction tests during this shift. All tests performed, during this shift, achieved the minimum required 97% relative compaction with moisture content within +/2% of optimum, per project specifications.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 2 of 3 ends

Test Results
Test #
Retest
Of Test Date Proctor ID Method
Soil
Classification
Optimum
Moisture
(%)
Maximum
Dry Density
(pcf)
In Place
Moisture
(%)
In Place
Dry
Density
(pcf)
In Place
Wet
Density
(pcf)
Probe
Depth
(in)
Percent
Compaction
Min Comp.
(%)
Optimum
Moisture
Tolerance
(%) Remark
10 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 16.2 107.0 124.3 6 99 97 -2 / 2 DP/MP
11 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 17.9 108.5 127.9 6 100 97 -2 / 2 DP/MP
12 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 18.0 107.7 127.1 6 99 97 -2 / 2 DP/MP
13 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 17.2 106.8 125.2 6 99 97 -2 / 2 DP/MP
14 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 18.0 106.0 125.1 6 98 97 -2 / 2 DP/MP
15 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 18.0 108.2 127.7 6 100 97 -2 / 2 DP/MP
16 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 17.3 107.2 125.7 6 99 97 -2 / 2 DP/MP
17 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 16.5 108.5 126.4 6 100 97 -2 / 2 DP/MP
Test Information
Test # Test Location Elevation Reference
Gauge
Make / Model / SN / Calibrated Field Technician
10 Levee Embankment: ~Sta. 67+60 (10th Lift) 38.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 11 Levee Embankment: ~Sta. 67+45 (11th Lift) 39.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 12 Levee Embankment: ~Sta. 67+70 (12th Lift) 39.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 13 Levee Embankment: ~Sta. 67+50 (13th Lift) 40.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 14 Levee Embankment: ~Sta. 67+65 (14th Lift) 40.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 15 Levee Embankment: ~Sta. 67+70 (15th Lift) 41.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 16 Levee Embankment: ~Sta. 67+60 (16th Lift) 41.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 17 Levee Embankment: ~Sta. 67+70 (17th Lift) 42.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio Remarks
DP/MP: Density Pass / Moisture Pass
Comments
Tests are "Direct Transmission" (Method A) unless probe depth is noted as "Backscatter". Gauge calibration data on file with the testing agency.

Page 1 of 2 ends

Soil Nuclear Gauge
Test Method: ASTM D 6938
Report Date: 06/18/2024
Client:

North Star Construction & Engineering, Inc.

Yuba City, CA 95993
Attn: Zach Milner - PE
Project:

SAFCA ATT Duct Bank
4537.x 003
Sacramento, CA
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION
4067+60
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 916-375-8706
West Sacramento
Test Results
Test #
Retest
Of Test Date Proctor ID Method
Soil
Classification
Optimum
Moisture
(%)
Maximum
Dry Density
(pcf)
In Place
Moisture
(%)
In Place
Dry
Density
(pcf)
In Place
Wet
Density
(pcf)
Probe
Depth
(in)
Percent
Compaction
Min Comp.
(%)
Optimum
Moisture
Tolerance
(%) Remark
18 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 16.2 111.7 129.8 6 103 97 -2 / 2 DP/MP
19 06/13/24 1778
(BC#3766)
B CL 18.0 108.4 16.5 106.7 124.3 6 98 97 -2 / 2 DP/MP
Test Information
Test # Test Location Elevation Reference
Gauge
Make / Model / SN / Calibrated Field Technician
18 Levee Embankment: ~Sta. 67+50 (18th Lift) 42.5 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio 19 Levee Embankment: ~Sta. 67+65 (19th Lift) 43.0 Troxler / 3440 / 61304 / 04/01/2024 Chavez, Emilio Remarks
DP/MP: Density Pass / Moisture Pass
Comments
Tests are "Direct Transmission" (Method A) unless probe depth is noted as "Backscatter". Gauge calibration data on file with the testing agency.

Page 2 of 2 ends

Soil Nuclear Gauge
Test Method: ASTM D 6938
Report Date: 06/18/2024
Client:

North Star Construction & Engineering, Inc.

Yuba City, CA 95993
Attn: Zach Milner - PE
Project:

SAFCA ATT Duct Bank
4537.x 003
Sacramento, CA
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION
4067+60
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 916-375-8706
West Sacramento

SUBMITTAL TRANSMITTAL
From: Date: 7/24/24
North Star Construction & Engineering, Inc.
1282 Stabler Lane #630-109
Yuba City, CA 95993
Contract Number: SAFCA JOC-014
JO-014.03.00
Submittal Number: 05A
Specification Section: 01 00 00
To:

CMID
9700 Goethe Road, Suite #D
Sacramento, CA 95827
Attention: John Engle
We are sending you X attached under separate cover
the following items:

X For Approval
For Your Use
As Requested
For Review and Comment
Remarks:

Line A X and referenced items are submitted with no exceptions to the Contract Documents.

Line B except for the attached deviations from the Contract Documents Submitted by: Rudy Rodriguez Date: 7/24/24
Site Visit
Date: 06/11/2024
Submitted By: Chavez, Emilio
Area: Soil
Category: Sampling
Sub Category: Soil Sampling
Contractor's Equipment: Cat 420GC excavator, Water Truck Frequency: Periodic
Determination: As Specified
Activity Summary
I arrived on site @ 10:30 a.m. to collect soil sample from the borrow site located at Echo Water Facility in Elk Grove.

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 1 of 4 ends

North Star crew used a water truck to
moisture conditioned the borrow
material.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 2 of 4 ends

Photo Comments:

North Star crew used a Cat 320GC
excavator to excavate and mix the
borrow material.

Activity Log
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 3 of 4 ends

General Information
Location Details: Stockpile @ Sims Rd & Laguna Station Rd Technician: Chavez, Emilio Sample Date: 06/17/2024
Alternate ID: BCI #3766 Sample Number: 1778
Material Type: Native Soil
Sampling Method: Sample From:

Test Results
Soil Classification: CL Color of Soil: Dark Brown
Sample Preparation Method Used: Moist Percent Retain from 9.5 mm (3/8 in) Sieve: 1 Percent Passing 9.5 mm (3/8 in) Sieve: 99 Compaction Method Used: B (ASTM D698 Method B) Type of Rammer Used: Manual
Specific Gravity of Sample: 2.65
Maximum Dry Density (lb/ft³): 108.4
Optimum Moisture: 18.0
Test Completed Date: 06/12/2024 Test Completed By: Bristow, David ASTM D698
West Sacramento
2491 Boatman Avenue
West Sacramento, CA 95691
Phone: 9163758706
Client:

North Star Construction & Engineering, Inc.

Attn: Zach Milner PE
Yuba City, CA 95993
Project:
4537.x 003
SAFCA ATT Duct Bank
Rio Linda Blvd.

ARCADE CREEK SOUTH LEVEE STATION 4067+60
Sacramento, CA

Page 1 of 2 ends

Appendix E.

American River North ULDC
Due Diligence, Geotech - Kleinfelder
24001006.001A/SAC24R164292 Page i of iv September 12, 2024 © 2024 Kleinfelder
ULDC GEOTECHNICAL FINDING –
AMERICAN RIVER NORTH LEVEE (STATION 3000+00 TO
3051+00) AND
NEMDC EAST LEVEE STATION (3001+50 TO 3029+00)

SACRAMENTO AREA FLOOD CONTROL AGENCY

SACRAMENTO COUNTY, CALIFORNIA
KLEINFELDER PROJECT # 24001006.001A
SEPTEMBER 12, 2024
Copyright 2024 Kleinfelder
All Rights Reserved

ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC PROJECT FOR WHICH THIS DATA REPORT WAS PREPARED.
24001006.001A/SAC24R164292 Page ii of iv September 12, 2024 © 2024 Kleinfelder
September 12, 2024
File No.: 24001006.001A
Mr. Pete Ghelfi, PE, Director of Engineering
Sacramento Area Flood Control Agency
1325 J Street, Suite 1700
Sacramento, CA 95814
SUBJECT: ULDC Geotechnical Finding –
American River North Levee (Station 3000+00 To 3051+00) and NEMDC East Levee Station (3001+50 to 3029+00)
Sacramento Area Flood Control Agency
Sacramento County, California
Dear Mr. Ghelfi:

This report presents Kleinfelder’s geotechnical evaluation of the existing American River North Levee (ARNL) from Railroad Avenue at Station 3000+00 to Lathrop Way at Station 3051+00 in Sacramento County, California, and Natomas East Main Drainage Canal East Levee (NEMDCEL) from Station 3001+50 to 3029+00 in Sacramento County, California.

This evaluation was performed for the Sacramento Area Flood Control Agency (SAFCA) to determine whether the ARNL and NEMDCEL study area can be certified from a geotechnical perspective to meet State of California Department of Water Resources Urban Levee Design Criteria (ULDC) (DWR, 2012).

This report contains Kleinfelder’s review and an opinion regarding whether the ARNL and NEMDCEL meet the geotechnical aspects of the ULDC (DWR, 2012) (soil sampling, testing, and logging; slope stability; underseepage; seismic vulnerability; levee geometry; interfaces and transitions; and floodwalls, retaining walls, and closure structures). Other sections of the ULDC (DWR, 2012) are not addressed in this letter and are being addressed by other consultants.

If you have questions regarding this report or if we may be of further assistance, please contact the undersigned.

Sincerely,
KLEINFELDER, INC.

Meredith Beswick Timothy A. Williams, PE, GE
Senior Engineer Sr. Principal Geotechnical Engineer
CC: Mr. Pro Mitra, PE/MBK Engineers ([email protected]) Ms. Becky Money, PE/MBK Engineers ([email protected]) 24001006.001A/SAC24R164292 Page iii of iv September 12, 2024 © 2024 Kleinfelder

TABLE OF CONTENTS

SECTION PAGE
1 INTRODUCTION .....................................................................................................................1

1.1 PROJECT BACKGROUND...................................................................................................... 1

1.2 PROJECT STATIONING AND DATUMS ................................................................................. 1

1.3 BACKGROUND AND CONSTRUCTION HISTORY................................................................... 2

1.3.1 ARNL 3000+00 to 3051+00 (USACE Station 157+30 to 208+30) ........................... 2

1.4 METHODOLOGY .................................................................................................................. 3

1.5 REFERENCED REPORTS........................................................................................................ 4

1.6 CRITERIA.............................................................................................................................. 6

1.7 WATER SURFACE ELEVATIONS............................................................................................ 6 2 ULDC GEOTECHNICAL CRITERIA REVIEW .................................................................................8

2.1 ULDC SECTION 7.3 SOIL SAMPLING, TESTING, AND LOGGING........................................... 8

2.1.1 Conclusion............................................................................................................ 11

2.2 ULDC SECTION 7.4 SLOPE STABILITY FOR INTERMITTENTLY LOADED LEVEES.................. 12

2.2.1 Conclusion............................................................................................................ 16

2.3 ULDC SECTION 7.5 UNDERSEEPAGE ................................................................................. 16

2.3.1 Swimming Pools................................................................................................... 20

2.3.2 Conclusion............................................................................................................ 20

2.4 ULDC SECTION 7.7 SEISMIC VULNERABILITY .................................................................... 20

2.4.1 Conclusion............................................................................................................ 21

2.5 ULDC SECTION 7.8 LEVEE GEOMETRY............................................................................... 21

2.5.1 Current Levee Geometry ..................................................................................... 23

2.5.2 Conclusion............................................................................................................ 24

2.6 ULDC SECTION 7.9 INTERFACES AND TRANSITIONS ......................................................... 24

2.6.1 Transition of NEMDCEL Cutoff Wall and ARNL Cutoff Wall Station 2999+70 (ARNL USACE Station 157+00)........................................................................................ 25

2.6.2 Transition End of ARNL Cutoff Wall Approximate Station 3013+45 (USACE Station 170+80) and Gravel Drained Toe Berm ............................................................... 25

2.6.3 Transition End of ARNL and Gravel Drained Toe Berm Approximate Station 3013+70 (USACE Station 171+10) to Del Paso Stoplog Structure Northwest Wall and Del Paso Stoplog Structure Southeast Wall to ARNL Approximate Station 3014+40 (USACE Station 171+75)........................................................................ 26

2.6.4 Transition of ARNL Approximate Station 3015+60 to UPRR Stoplog Structure Northwest Wall and Southeast Wall to ARNL Approximate Station 3016+00 .... 26

2.6.5 Interface of UPRR Trestle Bridge Piles Between Approximate Stations 3015+60 to 3016+00 ............................................................................................................... 27

2.6.6 Interface of Highway 160 Bridges Support Columns and Northern Abutment Between Approximate Stations 3016+40 to 3018+00......................................... 27

2.6.7 Transition Start of ARNL Cutoff Wall Approximate Station 3019+20 (ARNL USACE Station 176+50).................................................................................................... 28

2.6.8 Transition of ARNL Cutoff Wall Approximate Station 3052+30 (USACE Station 209+50)................................................................................................................ 29

2.6.9 Interface of UPRR Embankment on NEMDCEL Landside Slope Stations 3001+50 to 3029+00 ............................................................................................................... 29

2.6.11 Interface of NEMDCEL to City of Sacramento Pumping Plant No. 153 at Station 3014+00 ............................................................................................................... 30

2.6.12 Interface of NEMDC East Levee to West El Camino Avenue Floodwalls and Bridge at Station 3021+75............................................................................................... 30

2.6.13 Interface of NEMDCEL Telecommunications Vault Station 3025+00 .................. 31

2.6.14 Conclusion............................................................................................................ 31

2.7 ULDC SECTION 7.14 FLOODWALLS, RETAINING WALLS, AND CLOSURE STRUCTURES..... 31

2.7.1 Del Paso Boulevard Closure Structure................................................................. 32

2.7.2 UPRR Stoplog Structure ....................................................................................... 32

2.7.3 West El Camino Avenue Floodwalls..................................................................... 33

2.7.4 Conclusion............................................................................................................ 33 3 AMERICAN RIVER NORTH LEVEE STUDY AREA SUMMARY OF RESULTS ..................................34 4 LIMITATIONS .......................................................................................................................35 5 REFERENCES ........................................................................................................................37

FIGURES
1 ARNL and NEMDCEL Site Vicinity Map
2 ARNL and NEMDCEL Site Location Map

APPENDICES
A MBK, Engineers. “American River North Levee System – Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee. Dated July 1, 2024.

B MBK, Engineers. “American River North Levee System: Levee Geometry Analysis (ULDC). Sheets 5 through 10.

C “Seismic Performance Summary Report North Area Streams Levee Areas, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento County, California.” Dated February 12, 2024. Revised September 10, 2024. 24001006.001A/SAC24R164292 Page 1 of 40 September 12, 2024 © 2024 Kleinfelder
1 INTRODUCTION
___________________________________________________________________________________

1.1 PROJECT BACKGROUND
This report presents Kleinfelder’s geotechnical evaluation of the existing American River North Levee (ARNL) from Station 3000+00 to at Station 3051+00 and Natomas East Main Drainage Canal East Levee (NEMDCEL) from Station 3001+50 to 3029+00 in Sacramento County, California. The ARNL segment begins at the intersection with NEMDCEL (ARNL Station 3000+00) and continues southeast past Del Paso Blvd and Highway 160 to approximately 0.20 miles past the first intersection with Lathrop Way (ARNL Staton 3051+00). The NEMDCEL segment begins at the intersection of the Union Pacific Railroad (UPRR) (NEMDCEL Station 3001+50) and continues north slightly past Bay Drive. The project location relative to cities, rivers, and existing roadways is shown on Figures 1 and 2.

This evaluation was performed for Sacramento Area Flood Control Agency (SAFCA) to provide an opinion whether the ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) meet the geotechnical criteria within the State of California Department of Water Resources Urban Levee Design Criteria (ULDC) (DWR, 2012).

This report contains Kleinfelder’s review and an opinion regarding whether the ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) meet the geotechnical aspects of the ULDC (7.3 Soil Sampling, Testing, and Logging; 7.4 Slope Stability; 7.5 Underseepage; 7.7 Seismic Vulnerability;

7.8 Levee Geometry; 7.9 Interfaces and Transitions; and 7.14 Floodwalls, Retaining walls, and Closure Structures). Other sections of the ULDC are not addressed in this report and are being addressed by other consultants.

This report should be considered a “snapshot” of the condition of the levee system at this time.

Additional study and work may be needed due to the passage of time and if ULDC requirements change.

This report includes conclusions related to the geotechnical aspects of the levee. Conclusions are subject to the LIMITATIONS section of this report.

1.2 PROJECT STATIONING AND DATUMS
Elevation references in this report are in feet and are based on the North American Vertical Datum of 1988 (NAVD88). Project stationing used in this report is based on Department of Water Resources 24001006.001A/SAC24R164292 Page 2 of 40 September 12, 2024 © 2024 Kleinfelder
developed for the Urban Levee Evaluation (ULE) project. For ARNL, the previous reports use United States Army Corps of Engineers (USACE) project levee stationing. The USACE Stationing is noted in parenthesis and the stationing adopted for this study was estimated based upon site features.

1.3 BACKGROUND AND CONSTRUCTION HISTORY

1.3.1 ARNL 3000+00 to 3051+00 (USACE Station 157+30 to 208+30) ARNL from Station 3000+00 to 3051+00 is approximately 1 mile (5,100 feet) long. ARNL was originally constructed in the late 1800’s before USACE designed and constructed improvements in 1955 to bring the levee to Project standards (URS, 2015). Levee improvements consisting of a seepage cutoff wall and associated levee embankment modifications were completed along portions of the ARNL in two phases under an USACE contract. A slag-cement-cement-bentonite cutoff wall was installed in 2013 from approximate ARNL Station 3019+20 (ARNL USACE Station 176+50) to approximate Station 3052+30 (ARNL USACE Station 209+50). The cutoff wall was installed with a tip elevation between Elevations +5 and -10 feet. A gravel berm was installed on the landside toe between Station 3013+10 and Station 3013+70 (ARNL Stations 170+47.75 and 171+10). Another slag-cement-cement-bentonite cutoff wall was constructed in 2014 from the beginning of ARNL at approximate Station 2999+70 (ARNL USACE Station 157+00) to approximate Station 3013+45 (ARNL USACE Station 170+80) approximately 120 feet before the intersection of Del Paso Boulevard. The cutoff wall was installed with a tip Elevation (EL) between +10 and +15 feet. As part of the Kleinfelder Geomatrix Joint Venture (KGJV), Kleinfelder prepared the Design Documentation Report (KGJV, 2012a) and construction plans (KGJV, 2012j) for the project.

1.3.2 NEMDCEL 3001+50 to 3029+00
NEMDCEL from Station 3001+50 to 3029+00 is approximately half a mile (2,750 feet) long. NEMDCEL was originally constructed in the early 1930s, as documented in historical American River Flood Control District meeting minutes and correspondences (Kleinfelder, 2016a). Details from these notes indicate the levee was proposed to be constructed with a 10-foot-wide crown, 2H:1V (horizontal to vertical) landside slopes, and 3H:1V waterside slopes. A proposed typical cross section included with the documentation illustrated the levee being constructed on the waterside of the existing railroad embankment with the borrow source located on the waterside of the new levee. It is likely the railroad embankment, which predates the NEMDCEL, was also constructed using local materials. 24001006.001A/SAC24R164292 Page 3 of 40 September 12, 2024 © 2024 Kleinfelder
Levee embankment improvements were completed along the entire NEMDCEL under a SAFCA contract in 1996 (Spink, 1996). The improvements from Stations 3001+50 to 3029+00 included raising the crown elevation and an approximately 3-foot widening of the embankment toward the waterside. Typical keyways were 10 feet wide and 2 to 4 feet deep on the waterside, with deeper waterside keyways 4 to 7 feet deep in areas where ponded water was located at the waterside toe during construction (approximately NEMDCEL Stations 3013+50 to 3016+50). Kleinfelder prepared the geotechnical engineering report for the project (1995, Kleinfelder), and Kleinfelder representatives observed construction of the levee modifications (including material conformance and compaction testing) (1997, Kleinfelder). Kleinfelder engineers also confirmed key trenches were extended to penetrate underlying fine-grained and/or cemented soils.

The American River Flood Control District is the maintaining agency for both ARNL and NEMDCEL and is responsible for operations and maintenance.

1.4 METHODOLOGY
Kleinfelder performed seepage and slope stability analyses at selection locations for ARNL and NEMDCEL. ARNL analyses were documented in the Kleinfelder 2009 Seepage and Slope Stability Report, Kleinfelder Geomatrix Joint-Venture Design Documentation Report (DDR) (consisting of a compilation of design memorandums) (KGJV, 2012a), and a 2019 Seepage and Slope Stability Evaluation Memorandum with updated investigation and analysis for the UPRR stoplog structure (Kleinfelder, 2019). NEMDCEL analysis are included in the Kleinfelder Problem Identification Report and ULDC Geotechnical Results Summary (Kleinfelder, 2016a and 2016b). The reports containing these analyses are summarized in Section 1.4.

ARNL analyses were prepared using water surface elevations (WSE) based on 160,000 cubic feet per second (cfs) and 192,000 cfs American River flows developed by USACE in 2007 that were in use at the time the report was prepared. The NEMDCEL analyses were prepared using WSEs that were in use at the time the 2016 ULDC and PIR reports were prepared.

MBK Engineers (MBK) prepared new 200-year and Hydraulic Top of Levee (HTOL) WSEs for the current ULDC certification project which are designated, 2024 200-Year and 2024 HTOL WSEs (MBK, 2024). The 2024 HTOL WSE is lower than the highest WSE analyzed for the above referenced reports. The cross sections analyzed were critical location based on stratigraphy and levee geometry. Therefore, this summary was developed by comparing the previous analysis result at the previous higher WSE with the lower 2024 200-Year and 2024 HTOL WSEs. Since the existing analyses met project criteria at the 24001006.001A/SAC24R164292 Page 4 of 40 September 12, 2024 © 2024 Kleinfelder
previous higher WSEs, the existing analyses are considered to also meet criteria at the lower 2024 200- Year and 2024 HTOL WSEs. This procedure is described in Section 2 of this report.

1.5 REFERENCED REPORTS
This report includes results from previous studies performed by Kleinfelder and URS for the ARNL and NEMDCEL study areas. Kleinfelder has reviewed and used existing analyses from the following reports. • Kleinfelder, 1995. “Geotechnical Evaluation of Levee Improvements, Natomas East Main Drainage Canal, Unit 3-East Levee, Sacramento, California.” Dated April 27, 1995. • Kleinfelder, 1997. “Final Report, Field Compaction Test Results, NEMDC 2B/3B, Sacramento, California.” Compaction testing summary. Dated February 13, 1997. • Kleinfelder, 2009. “Seepage and Slope Stability Report, American River Common Features, River Mile 2.0 to 3.6, Sacramento, California.” Dated August 7, 2009. • Kleinfelder, 2013. “Geotechnical Data Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee),”. Dated May 31, 2013.
• Kleinfelder, 2016a. “Problem Identification Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee),”. Dated September 18, 2013. Revised April 29, 2016. • Kleinfelder, 2016b. “ULDC Geotechnical Results Summary, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee),”. Dated April 26, 2016. • Kleinfelder, 2019. “Draft Seepage and Slope Stability Evaluation for 115,000 CFF WSE, Del Paso Boulevard to UPRR Tracks, USACE Project Station 171+50 to 173+00, American River North Levee, Sacramento, California.” Dated April 11, 2019.
• KGJV, 2012a. “Final Design Document Report, American River Common Features, American River North Levee, River Mile 2.0 to 3.6,”. Dated August 20, 2012. (Select design memorandum and reports included in the DDR referenced below)
24001006.001A/SAC24R164292 Page 5 of 40 September 12, 2024 © 2024 Kleinfelder
o KGJV, 2010. “Remediation Methods Development, American River Common Features, River Mile 2.0 to 3.6,”. Dated December 20, 2010.
o KGJV, 2012b. “Subsurface Profile Evaluation Based on Additional Data and Cutoff Wall Sensitivity Analysis, Sation 189+50 to Station 209+50, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated March 7, 2012. o KGJV, 2012c. “Seepage Evaluation, UPRR Stoplog Structure, Station 173+15, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated March 7, 2012.
o KGJV, 2012d. “Seepage Evaluation, Del Paso Boulevard Closure Structure, Station 171+20, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum.

Dated March 7, 2012.
o KGJV, 2012e. “Seepage and Slope Stability Evaluation, Del Paso Tie-In, Station 170+40 to 171+10, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum.

Dated March 8, 2012.
o KGJV, 2012f. “Seepage and Slope Stability Evaluation, Del Paso Boulevard to UPRR Tracks, Station 171+50 to 173+00, American River Common Features RM 2 to 3.6,” KGJV Memorandum. Dated March 14, 2012.
o KGJV, 2012g. “Cutoff Wall Sensitivity Analysis, Station 176+00 to Station 189+50, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated March 23, 2012.
o KGJV, 2012h. “Filter Criteria Check for Gravel Berm, Station 170+40 to 171+10, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated June 29, 2012.
o KGJV, 2012i. “Cutoff Wall Sensitivity Analysis, Station 157+00 to Station 170+80,” KGJV Memorandum. Dated October 13, 2011. Revised July 9, 2012. • KGJV, 2012j. “American River Common Features (Remaining Sites) WRDA 99 – NEMDC South.” As-built drawings Contract No. W91238-12-C-0041. File Date July 3, 2012. • URS, 2015. “Geotechnical Evaluation Report, American River Study Area”. Dated January 2015. 24001006.001A/SAC24R164292 Page 6 of 40 September 12, 2024 © 2024 Kleinfelder
• USACE, 2013. “American River Common Features, WRDA 99 – NEMDC North,” As-Built Documents. Dated Jun 1, 2013.

In addition to the reports referenced above, Kleinfelder has reviewed the design and construction documents related to the ARNL and NEMDCEL study area. These documents are contained in the list of references, which are included as in Section 5 of this report.

1.6 CRITERIA
The purpose of this study was to review existing geotechnical information available for these levee segments to perform an evaluation as to whether these levees currently meet the geotechnical requirement of the ULDC. This information is contained in the reports referenced in Section 1.4. This information was compared to criteria from the following references:
• USACE EM 1110-2-1913 “Design and Construction of Levees,” dated April 30, 2000 • USACE ETL 1110-2-569 “Design Guidance for Levee Underseepage,” dated May 1, 2005 • USACE SPK-EDG, “Standard Operating Procedure 3, Geotechnical Levee Practice, US Army Corps of Engineers, Sacramento District, Geotechnical Engineering Branch” dated May 2022 • US Title 44 Code of Federal Regulations 65.10: Mapping of Areas Protected by Levee Systems, dated October 1, 2011
• Urban Levee Design Criteria (ULDC), State of California Department of Water Resources, dated May 2012

1.7 WATER SURFACE ELEVATIONS
Water surface elevations were provided to Kleinfelder for the reports referenced in Section 1.4, above.

The following table lists these WSEs.
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Table 1.1
Water Surface Elevation Reference Summary
Levee WSE
Elevation
Range
(NAVD88, ft)
Source Date
ARNL
Previous ARNL Reports
160,000 cfs 38.7 – 40.2 Range of WSE reported for
analysis in Kleinfelder 2009
Seepage and Stability Report.

WSE source from 2007 USACE
American River Common
Features Design Documentation
Report.

May 2007
192,000 cfs 38.7 – 40.7
ULDC Geotechnical Finding, 2024
200-Year
WSE 35.64 – 37.08 MBK, Engineers. “American River North Levee System – Determination of the Urban
Levee Design Criteria Design
Water Surface Elevation,
Minimum Top of Levee, and
Hydraulic Top of Levee. Dated
July 1, 2024.

July 1, 2024 Hydraulic
Top of
Levee
(HTOL)

38.64 -40.08

NEMDCEL
Previous NEMDCEL Reports
100-Year 36.16 – 37.14
MBK Engineers “Base Flood
Elevations for SAFCA Levee
Certification Reaches,” provided
via email 7/29/13.

July 29, 2013
200-Year 36.95 – 38.18 MBK Engineers Table entitled
“ NAS WSE data - transmitted to
Kleinfelder 02-18-14-
160000CFS.xls”
February 18,2014
HTOL 39.95 -41.18
ULDC Geotechnical Finding, 2024
200-Year 35.86 – 36.60 MBK, Engineers. “American River
North Levee System –
Determination of the Urban
Levee Design Criteria Design
Water Surface Elevation,
Minimum Top of Levee, and
Hydraulic Top of Levee. Dated
July 1, 2024.

July 1, 2024
HTOL 38.86 – 39.60
The 2024 200-year DWSE and HTOL WSEs (MBK, 2024) used for the current ULDC evaluation were provided in tabular form at 100-foot intervals along the ARNL and NEMDCEL. The 2024 200-year DWSE and HTOL WSE (MBK, 2024) are included in Appendix A.
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2 ULDC GEOTECHNICAL CRITERIA REVIEW
___________________________________________________________________________________ Kleinfelder performed a review of existing reports and analyses contained in those reports referenced in Section 1.4, above. This review was performed to determine whether the subject ARNL and NEMDCEL meet the ULDC from a geotechnical perspective for the following sections. • 7.3 Soil Sampling, Testing, and Logging
• 7.4 Slope Stability
• 7.5 Underseepage
• 7.7 Seismic Vulnerability
• 7.8 Levee Geometry
• 7.9 Interfaces and Transitions
• 7.14 Floodwalls, Retaining Walls, and Closure Structures This evaluation includes a review of existing information referenced in this report and has not included performance of new analysis or field investigation. Where available, construction inspection records have also been reviewed.

The following sections of this report contain a summary of our analysis.

2.1 ULDC SECTION 7.3 SOIL SAMPLING, TESTING, AND LOGGING This section contains a summary of the review of existing information for ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) with regards to ULDC Section 7.3 Soil Sampling, Testing, and Logging. The general requirements of this section are outlined below.

ULDC 7.3 requires soil sampling, testing, and logging per standard procedures prescribed in guidance documents, including the USACE Sacramento District’s Geotechnical Levee Practice Standard Operating Procedures (SPK SOP) (USACE, 2022) and DWR’s Division of Flood Management Soil and Rock Logging, Classification, Description and Presentation Manual (2009). This includes an evaluation of soil exploration quantity and location as outlined in the SPK SOP (USACE, 2022). Based on this document, explorations for a feasibility levee evaluation should be obtained at a spacing of approximately 1,000 feet along the levee crest.

For preconstruction and design studies a spacing of approximately 500 feet along the waterside toe, levee crown, landside toe. Exploration depths should be a minimum of 4 times the levee height and extending to an appropriate stratum. Explorations that did not meet 24001006.001A/SAC24R164292 Page 9 of 40 September 12, 2024 © 2024 Kleinfelder
the requirements outlined (e.g., explorations that were not drilled deep enough) above were not included.

The SPK SOP (USACE 2022) recommends a thorough evaluation of existing information as part of a levee evaluation program. This includes a review of original construction (if available), improvements, performance history, existing subsurface information, and regional and local geomorphology. The standard also recommends the use of cone penetrometers (CPTs) and geophysics to supplement borings, where appropriate.

In addition, where available, the as-built plans, conformance laboratory tests, and in-place compaction tests for the construction and improvements of each levee were retained as part of the ULDC evaluation. This information was used to evaluate the levee geometry and material properties within the newly constructed and improved levee sections.

ARNL from Station 3000+00 to 3051+00 is approximately 1 mile (5,100 feet) long and NEMDCEL from Station 3001+50 to 3029+00 is approximately half a mile (2,750 feet) long. To meet the approximate number of explorations for both levees with a spacing of approximately 500 feet for levee design, 16 explorations each for waterside toe, levee crown, landside toe, and landside field (64 total explorations or 43 explorations per mile) would be needed.

ARNL and NEMDCEL has been explored by Kleinfelder, DWR, and USACE for levee evaluations and improvement projects. Explorations include drilled borings and cone penetrometer soundings (CPT). The explorations reviewed by Kleinfelder included those advanced for the SAFCA FEMA Levee Accreditation program, the DWR Urban Levee Evaluation (ULE) program, and previous studies by others. To be included in the summary, the explorations were evaluated for depth (generally a minimum of 4 times the levee height for crest explorations and 3 times the levee height for toe and field explorations), sampling frequency, laboratory testing, and classification. For example, shallow borings that only assess the levee embankment were not included in the summary. Tables 2.1 and 2.2, below, summarize the number of explorations performed for each levee location that meet the exploration requirement described in SPK SOP.
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Table 2.1
Summary of Exploration Locations and Spacing for ARNL
Exploration
Location
Number of Explorations Spacing (ft)
Meets SPK
SOP 2022
All
Explorations
Max
Meets/All
Min
Meets/All
Average
Meets/All
Waterside Toe 6 8 1,220/1,099 18/18 736/593
Levee Crown 12 21 734/577 38/5 371/218
Landside Toe 3 3 2,142 1,320 1,639
Landside Field 0 0 - - -
Total 21 32
Average Per
Mile 22 33
Table 2.2
Summary of Exploration Locations and Spacing for NEMDCEL Exploration
Location
Number of Explorations Spacing (ft)
Meets SPK
SOP 2022
All
Explorations
Max
Meets/All
Min
Meets/All
Average
Meets/All
Waterside Toe 1 3 1,960/1,225 790/140 1,960/700
Levee Crown 2 6 1,056/786 916/10 986/416
Landside Toe 0 0 - - -
Landside Field 0 0 - - -
Total 3 9
Average Per
Mile 6 17
Sampling for the explorations used standard penetration testing at regular intervals of every 2 ½ feet to every 5 feet, documenting blow counts, and field soils descriptions. Laboratory testing was performed on select samples generally consistent with DWR’s Division of Flood Management Soil and Rock Logging, Classification, Description and Presentation Manual (2009) such as sieve analysis, Atterberg limits, unit weight, water content, permeability, and strength testing. Cone penetration tests were performed near soil borings to aid in interpretation. The total number of explorations is not within the range of explorations specified in the SPK SOP for levee crown, waterside toe, landside toe, and landside field borings.

As part of previous geotechnical evaluations of the ARNL and NEMDCEL area, geologic and geomorphologic mapping was performed of the area.
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Along NEMDCEL, the Holocene alluvium layers comprised of soft fine-grained soils dissected by lenses of sand. The Holocene alluvium are approximately ten feet thick below the NEMDCEL landside toe near the Station 3001+50 and thin to less than 5 feet thick below the NEMDCEL landside toe. Underlying the Holocene Formation is the Riverbank Formation. The Riverbank Formation in this area is typically consolidated and very dense; the very dense and/or consolidated layers of this formation locally referred to as “hardpan” (Kleinfelder, 2016a). The shallow surficial channel deposits were generally cut off with the inspection trench along NEMDCEL (Kleinfelder, 2016a). Riverbank Formation soils are characterized by low to very low hydraulic conductivities and are generally a low risk for seepage through the levee foundation (‘underseepage'). The Geophysical HEM (helicopter-based electromagnetics) surveys were performed along the levee for the ULE project (URS, 2010) and provided a continuous record of the subsurface conditions along the levee. In the subject portion of the NEMDCEL, these surveys generally showed a moderate to low resistivity, which is typical of fine-grained soils such as silts and clays. In the dense to cemented hardpan soils of the Riverbank Formation also show a moderate to low resistivity, which was confirmed in the subsurface explorations.

Along ARNL, the Recent and Holocene alluvium extends 20 to 40 feet below the landside ARNL toe.

Underlying the Holocene Formation is the Modesto Formation. The Modesto Formation is late Pleistocene age and consists predominately of medium dense silty sands. The Modesto Formation varies in thickness along this length of ARNL and is approximately 10 to 20 feet thick. Underlying the Modesto Formation is the Riverbank Formation. The cementitious cutoff walls were installed along ARNL to a tip Elevation of between +15 and -5, which cuts off shallow sand lenses and provides added strength to the levee embankment and foundation. The Geophysical HEM in the subject portion of the NEMDCEL, generally showed a moderate resistivity, which is typical of soils such as sandy silts and sandy clays.

2.1.1 Conclusion
Based on the above information, the number of explorations does not meet the minimum number of explorations, and an exception is needed. The intent of an exploration program for a levee evaluation project is to adequately characterize subsurface conditions such that the levee can be evaluated and improvements, if needed, can be designed, and constructed. It is Kleinfelder’s opinion that in addition to the subsurface explorations, additional and appropriate information including geologic and geomorphologic mapping, inspection trench observation, cutoff wall observation, and continuous HEM data, was collected and reviewed to provide an adequate assessment of the subsurface conditions as outlined in the ULDC and SPK SOP for levee evaluation. Therefore, it is Kleinfelder’s opinion that the ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) geotechnical 24001006.001A/SAC24R164292 Page 12 of 40 September 12, 2024 © 2024 Kleinfelder
evaluation meets the intent of the guidance outlined above and meets the requirements of ULDC 7.3 for Soil Sampling, Testing, and Logging through Exception.

2.2 ULDC SECTION 7.4 SLOPE STABILITY FOR INTERMITTENTLY LOADED LEVEES The section contains a summary of the review of the existing reports and analyses performed for ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) as it applies to ULDC Section 7.4 Slope Stability for Intermittently Loaded Levees. ULDC defines an intermittently loaded levee as:
“Intermittently loaded levee means a levee that does not experience a water surface elevation of one foot or higher above the elevation of the levee toe at least once a day for more than 36 days per year on average.”
ARNL and NEMDCEL are generally subject to short term flood events where the water rarely reaches the landside embankment toe. As such, ARNL and NEMDCEL are considered Intermittently Loaded Levees.

The general requirements of ULDC Section 7.4 Slope Stability for Intermittently Loaded Levees are outlined below.

ULDC 7.4 requires slope stability analysis for the design water surface elevation (DWSE) and at the Hydraulic Top of Levee (HTOL) WSE. “Engineers should use sound engineering judgment and guidance from EM 1110-2-1902 to decide what constitutes a minor, insignificant slip surface versus a sliding surface that threatens the integrity of the levee.

These determinations should be based on performance history, levee geometry, type of levee fill material, stratigraphy of the levee embankment and foundation soils, seepage conditions (including pore water pressures calculated for the seepage analysis), soil strength characteristics, and potential for erosion. Those surfaces which significantly threaten the integrity of the levee must meet minimum slope stability criteria.” Steady-state landside stability and rapid drawdown waterside stability should be evaluated using the minimum factors of safety summarized in Table 1.

Stability Analysis ULDC Minimum Factor of Safety1
Steady-State DWSE, Landside Slope 1.4
Steady-State HTOL WSE, Landside Slope 1.2
Rapid Drawdown DWSE, Waterside Slope 1.0-1.22
End of Construction 1.33

1. Critical failure surface should intersect the levee crown and exceed a minimum of 3-foot depth into the level slope.

2. Minimum factor of safety dependent on time extent DWSE may have saturated the waterside levee slope.

3. End of Construction in performed for newly constructed levees 24001006.001A/SAC24R164292 Page 13 of 40 September 12, 2024 © 2024 Kleinfelder
Through seepage occurs where the phreatic seepage surface exits above the levee toe on the landside levee slope. For through seepage, reaches where the phreatic seepage surface exited on a levee slope that is composed of erodible material (sands and non-plastic silts and silty sands) were generally considered to not meet criteria.

Detailed discussions of the slope stability analyses previously performed are discussed in the reports listed in Section 1.4 and included in the reference list. These analyses results were compared with the current 2024 200-year and HTOL WSEs (MBK, 2024). Since the previously performed analyses were analyzed with a WSE that is above the current 2024 200-year and HTOL WSEs and met slope stability criteria and soil and geometry conditions have not changed, the analyses are considered to meet criteria for the current WSEs. Table 2.3 contains the previously performed analysis results with the design WSE and the current 2024 WSEs.
24001006.001A/SAC24R164292 Page 14 of 40 September 12, 2024 © 2024 Kleinfelder
Table 2.3
Stability Analyses Comparison Summary
Approximate
ULE Station
USACE
Station
Constructed
Remediation
Reference Report Summary 2024 ULDC Summary
Modeled
Remediation Report Reference
Highest
Previously
Modeled
WSE
Meets/Does Not Meet
2024 WSE
(ft)
Difference
2024 WSE –
Highest
Previously
Modeled WSE
(ft)
Meets/Does Not Meet
Through
Seepage1
Steady -State
Landside
Stability FOS
Rapid Drawdown
Waterside Stability
FOS2
Through
Seepage1
SteadyState
Landside
Stability
Rapid
Drawdown
Waterside
Stability
ARNL
3011+25
168+60 COW EL +15 ft
COW EL +15 ft
and
Reconstruct
Slopes to
2H:1V (As-built
Condition is
2H:1V)
October 13, 2011,
Revised July 9, 2011:

Cutoff Wall Sensitivity
Analysis Sation 157+00 to
Station 170+80 Memo

38.7 (2007 -
192 kfs) Meets
Meets, 1.40 -

1.47 (compilation
of sensitivity
analysis)
Meets, 1.28
(existing conditions
2009 Seepage and
Stability Report)

35.53 200-
yr
-3.17 Meets Meets Meets

38.53 HTOL -0.17 Meets Meets
Not
Applicable
ARNL
3013+55 170+90 Gravel Berm Gravel Berm
March 8, 2012, Seepage
and Slope Stability
Evaluation, Del Paso Tiein, Station 170+40 to
171+10

38.7 (2007 -
192 kfs) Meets Meets, 1.47 Not Analyzed

35.56 200-
yr
-3.14 Meets Meets Not Analyzed

38.56 HTOL -0.14 Meets Meets
Not
Applicable
ARNL
3013+65
171+00 Gravel Berm Gravel Berm
March 8, 2012, Seepage
and Slope Stability
Evaluation, Del Paso Tiein, Station 170+40 to
171+10

38.7 (2007 -
192 kfs) Meets Meets, 1.64 Not Analyzed

35.56 200-
yr
-3.14 Meets Meets Not Analyzed

38.56 HTOL -0.14 Meets Meets
Not
Applicable
ARNL
3013+85 171+20
Existing
Conditions – Del
Paso Closure
Structure
Existing
Conditions –
Del Paso
Closure
Structure
March 7, 2012, Seepage
Evaluation, Del Paso
Boulevard Closure
Structure, Station 171+20

38.7 (2007 -
192 kfs) Closure Structure Analyzed for Underseepage Only

35.55 200-
yr
-3.15
Closure Structure Analyzed for

38.55 Underseepage Only
HTOL -0.15
ARNL
3014+40
171+75 Existing
Conditions
Existing
Conditions
April 11, 2019: Seepage
and Slope Stability
Evaluation for 115,000
CFS WSE Del Paso Blvd to
UPRR Tracks, USACE
Project Station 171+50 to
173+00 Memo

38.9 (2019 -
HTOL)
Meets Meets, 1.41 Not Analyzed

35.55 200-
yr
-3.35 Meets Meets Not Analyzed

38.55 HTOL -0.35 Meets Meets
Not
Applicable
ARNL
3015+80
173+15
Existing
Conditions –
UPRR Closure
Structure
Existing
Conditions –
UPRR Closure
Structure
March 7, 2012, Seepage
Evaluation, UPRR Stoplog
Structure, Station 173+15

39.0 (2007 -
192 kfs) Meets Not Analyzed Not Analyzed

35.73 200-
yr
-3.27 Meets
Not
Analyzed
Not Analyzed

38.73 HTOL
-0.27 MeetsNot
Analyzed
Not
Applicable
ARNL
3018+70 176+00 Existing Conditions
Existing
Conditions
(Cutoff wall
with El +5 ft
tip Starts at
176+50)
December 20, 2010,
Remediation Methods
Dev Report

39.2 (2007 -
192 kfs) Meets Meets, 1.5 Not Analyzed

36.1 200-yr
-3.10 Meets Meets Not Analyzed

39.1 HTOL -0.103 Meets Meets
Not
Applicable
24001006.001A/SAC24R164292 Page 15 of 40 September 12, 2024 © 2024 Kleinfelder
Table 2.3 (cont.)
Stability Analyses Comparison Summary
Approximate
ULE Station
USACE
Station
Constructed
Remediation
Reference Report Summary 2024 ULDC Summary
Modeled
Remediation Report Reference
Highest
Previously
Modeled
WSE
(ft)
Meets/Does Not Meet
2024 WSE
(ft)
Difference 2024
WSE – Highest
Previously
Modeled WSE
(ft)
Meets/Does Not Meet
Through
Seepage1
Steady -State
Landside
Stability FOS
Rapid Drawdown
Waterside Stability
FOS2
Through
Seepage1
SteadyState
Landside
Stability
Rapid
Drawdown
Waterside
Stability
ARNL
3025+00 NA COW EL +5 ft COW EL -5 ft January 2015, American River ULE GER 40 Meets Meets, 1.58 Not Analyzed

36.35 200-
yr
-3.65 Meets Meets Not Analyzed

39.35 HTOL -0.65 Meets Meets Not Applicable
ARNL
3026+30 183+60 COW EL -5 ft COW EL +0 ft
March 23, 2012: Cutoff
Wall Sensitivity Analysis
Station 176+00 to Station
189+50 Memo

39.8 (2007 -
192 kfs) Meets Meets, 1.393

1.32 (existing conditions
2009 Seepage and
Stability Report)

36.36 200-
yr
-3.44 Meets Meets Meets

39.36 HTOL -0.44 Meets Meets Meets
ARNL
3034+70
192+00 COW EL -4 to-9
ft COW EL +5 ft
March 7, 2012:

Subsurface Profile
Evaluation Based on
Additional Data and
Cutoff Wall Sensitivity
Analysis, Station 189+50
to 209+50 Memorandum

40.1 (2007 -
192 kfs) Meets Meets, 1.41

1.29 (existing conditions
2009 Seepage and
Stability Report)

36.52 200-
yr
-3.58 Meets Meets Meets

39.52 HTOL -0.58 Meets Meets Meets
ARNL
3044+50
201+80 COW EL -5 ft COW EL +0 ft
March 7, 2012:

Subsurface Profile
Evaluation Based on
Additional Data and
Cutoff Wall Sensitivity
Analysis, Station 189+50
to 209+50 Memorandum

40.7 (2007 -
192 kfs) Meets Meets, 1.46

1.28 (existing conditions
2009 Seepage and
Stability Report)

36.96 200-
yr
-3.74 Meets Meets Meets

39.96 HTOL -0.74 Meets Meets Meets

NEMDCEL
3030+004 NA Existing Conditions
Existing
Conditions
2016 ULDC Geotechnical
Results Summary Report

41.1 (2016
HTOL) Meets Meets, 1.59
Meets, 1.20
(existing conditions
2016 ULDC Summary
Report)

36.43 200-
yr
-4.67 Meets Meets Meets

39.43 HTOL -1.67 Meets Meets Meets
1 – For through seepage, reaches where the phreatic seepage surface exited on a levee slope (i.e., through seepage) that is composed of erodible material (sands and non-plastic silts and silty sands) and were generally considered to not meet criteria.
2 —Rapid Drawdown not performed on all analysis sections in reference document. Rapid drawdown was only performed for critical sections. Acceptance was based on review of the sections and concurrence that critical sections were analyzed and met criteria.
3 – Stability is considered meeting; the actual constructed condition was a 5-foot deeper cutoff wall and the 2024 WSE are 3.44 feet lower than the modeled WSE. 4 –Station 3030+00 is 100 feet outside the section of NEMDCEL being certified. This section location was originally the end of the certification reach; however, the subsequent SAFCA construction project extended to Station 3029+00, which became the new boundary for the certification. The cross section at 3030+00 from the PIR and ULDC Geotechnical Results Summary was reviewed and is considered the critical cross section for the certification reach and, therefore, is used for this analysis.
24001006.001A/SAC24R164292 Page 16 of 40 September 12, 2024 © 2024 Kleinfelder
Based on this review the following conclusions can be made:
• Analysis cross sections model slope stability along ARNL (Station 3000+00 to 3051+00) and NEMDCEL (Station 3001+50 to 3029+00) at critical locations. • The 2024 200-year and HTOL WSEs are lower than the WSE modeled in the existing analyses. • The modeled improvements at the analysis cross section were the same or less conservative than the constructed improvements and met criteria at the analyzed locations.

2.2.1 Conclusion
Based on the above review, it is Kleinfelder’s opinion that ARNL (Station 3000+00 to 3051+00) and NEMDCEL (Station 3001+50 to 3029+00) meets the requirements of ULDC 7.4 Slope Stability for Intermittently Loaded Levees.

2.3 ULDC SECTION 7.5 UNDERSEEPAGE
This section contains a summary of the review of the existing reports and analyses performed for ARNL (Station 3000+00 to 3051+00) and NEMDCEL (Station 3001+50 to 3029+00) as it applies to ULDC Section

7.5 Underseepage for Intermittently Loaded Levees. As discussed in Section 2.2, the ARNL and NEMDCEL are intermittently loaded levees. The general requirements of ULDC Section 7.5 Underseepage for Intermittently Loaded Levees are outlined below.

ULDC 7.5 requires seepage analysis performed for the design water surface elevation (DWSE) and the hydraulic top of levee (HTOL) WSE. Exit gradients measured at the landside levee toe, seepage berm toe, ditches, canals, depressions, or areas of thin blanket. The allowable maximum exit gradient is summarized in the table below.

Seepage Analysis Location Allowable Maximum Exit
Gradient
Steady-State DWSE
Landside Levee Toe 0.51
Ditches, canals, depressions,
berms 0.5-0.82
Steady-State HTOL WSE
Landside Levee Toe 0.6
Ditches, canals, depressions,
berms 0.6-0.92

1. The allowable underseepage exit gradient through the combined seepage berm/blanket layer between the levee toe and the seepage berm toe for a water surface set at the DWSE is determined by interpolation, using 0.5 at the levee toe and 0.8 at the seepage berm toe. 24001006.001A/SAC24R164292 Page 17 of 40 September 12, 2024 © 2024 Kleinfelder

2. Maximum allowable exit gradient at the landside levee toe is 0.5 and up to 0.8 at 150 feet from the levee toe, using linear interpolation for distances in between. ULDC does allow for higher exit gradients at the seepage berm toe provided sound engineer judgement, and additional analysis.

For the HTOL, “In general if the berm is less than 100-ft wide, the maximum exit gradient may increase by up to 20 percent of the DWSE maximum exit gradient.“ ULDC 7.5 provides criteria for blanket layer soils with saturated unit weights of 112 pcf or less. DCNL stratigraphy blanket layers did not require this analysis because saturated unit weights were greater than the minimum specified.

Detailed discussions of the seepage analyses previously performed are discussed in the reports listed in Section 1.4 and included in the reference list. These analyses results were compared with the current 2024 200-year and HTOL WSEs (MBK, 2024). Since the previously performed analyses were analyzed with a WSE that is above the current the 2024 200-year and HTOL WSEs and met seepage criteria, the analyses are considered to meet criteria for the current WSEs. Table 2.4 contains the previously performed analysis results with the previously used design WSE and the current 2024 WSEs. 24001006.001A/SAC24R164292 Page 18 of 40 September 12, 2024 © 2024 Kleinfelder
Table 2.4
Seepage Analyses Comparison Summary
Approximate
ULE Station
USACE
Station
Constructed
Remediation
Reference Report Summary 2024 ULDC Summary
Modeled
Remediation Report Reference
Highest
Previously
Modeled WSE
(ft)
Meets/Does Not Meet
2024 WSE
(ft)
Difference 2024
WSE – Highest
Previously
Modeled WSE
(ft)
Meets/Does Not Meet
Underseepage Underseepage
ARNL
3011+25 168+60 COW EL +15 ft
COW EL +15 ft and
Reconstruct Slopes to
2H:1V (As-built
Condition is 2H:1V)
October 13, 2011, Revised July 9,
2011: Cutoff Wall Sensitivity
Analysis Sation 157+00 to Station
170+80 Memo

38.7 (2007 -
192 kfs)
Meets,

0.22 to 0.31 (compilation of
sensitivity analysis)

35.53 200-yr -3.17 Meets

38.53 HTOL -0.17 Meets
ARNL
3013+55 170+90 Gravel Berm Gravel Berm
March 8, 2012, Seepage and
Slope Stability Evaluation, Del
Paso Tie-in, Station 170+40 to
171+10

38.7 (2007 -
192 kfs)
Meets,

0.50 (CL/ML) (berm toe)

0.17 (Railroad Dr, SC/SM, ML/CL)

35.56 200-yr -3.14 Meets

38.56 HTOL -0.14 Meets
ARNL
3013+65 171+00 Gravel Berm Gravel Berm
March 8, 2012, Seepage and
Slope Stability Evaluation, Del
Paso Tie-in, Station 170+40 to
171+10

38.7 (2007 -
192 kfs)
Meets,

0.38 (CL/ML) (berm toe)

0.16 (Railroad Dr, SC/SM, ML/CL)

35.56 200-yr -3.14 Meets

38.56 HTOL -0.14 Meets
ARNL
3013+85 171+20 Existing Conditions – Del Paso Closure Structure Existing Conditions –
Del Paso Closure
Structure
March 7, 2012, Seepage
Evaluation, Del Paso Boulevard
Closure Structure, Station 171+20

38.7 (2007 -
192 kfs)
Meets, 0.43 (along face of closure
cutoff wall)

35.55 200-yr -3.15 Meets

38.55 HTOL -0.15 Meets
ARNL
3014+40
171+75 Existing Conditions Existing Conditions
April 11, 2019: Seepage and
Slope Stability Evaluation for
115,000 CFS WSE Del Paso Blvd
to UPRR Tracks, USACE Project
Station 171+50 to 173+00 Memo

38.9 (2019 -HTOL)
Meets,

0.31 35.55 200-yr -3.35 Meets

38.55 HTOL -0.35 Meets
ARNL
3015+80
173+15 Existing Conditions –
UPRR Closure Structure
Existing Conditions –
UPRR Closure
Structure
March 7, 2012, Seepage
Evaluation, UPRR Stoplog
Structure, Station 173+15

39.0 (2007 -
192 kfs) Meets, 0.47

35.73 200-yr -3.27 Meets

38.73 HTOL -0.27 Meets
ARNL
3018+70 176+00 Existing Conditions
Existing Conditions
(Cutoff wall with El +5
ft tip Starts at 176+50)
December 20, 2010, Remediation
Methods Dev Report

39.2 (2007 -
192 kfs) Meets, 0.42

36.1 200-yr -3.10 Meets

39.1 HTOL -0.103 Meets
ARNL
3025+00 NA COW EL +5 ft COW EL -5 ft January 2015, American River ULE GER 40 Meets, <0.10

36.35 200-yr -3.65 Meets

39.35 HTOL -0.65 Meets
ARNL
3026+30 183+60 COW EL -5 ft COW EL +0 ft
March 23, 2012: Cutoff Wall
Sensitivity Analysis Station
176+00 to Station 189+50 Memo

39.8 (2007 -
192 kfs) Meets, 0.14

36.36 200-yr -3.44 Meets

39.36 HTOL -0.44 Meets
ARNL
3034+70
192+00 COW EL -4 to -9 ft COW EL +5 ft
March 7, 2012: Subsurface Profile
Evaluation Based on Additional
Data and Cutoff Wall Sensitivity
Analysis, Station 189+50 to
209+50 Memorandum

40.1 (2007 -
192 kfs)
Meets,

0.11 (CL/ML), 0.12 (CL/ML, SM,
CL/ML)

36.52 200-yr -3.58 Meets

39.52 HTOL -0.58 Meets
24001006.001A/SAC24R164292 Page 19 of 40 September 12, 2024 © 2024 Kleinfelder
Table 2.4 (cont.)
Seepage Analyses Comparison Summary
Approximate
ULE Station
USACE
Station
Constructed
Remediation
Reference Report Summary 2024 ULDC Summary
Modeled
Remediation Report Reference
Highest
Previously
Modeled WSE
(ft)
Meets/Does Not Meet
2024 WSE
(ft)
Difference 2024
WSE – Highest
Previously
Modeled WSE
(ft)
Meets/Does Not Meet
Underseepage Underseepage
ARNL
3044+50
201+80 COW EL -5 ft COW EL +0 ft
March 7, 2012: Subsurface Profile
Evaluation Based on Additional
Data and Cutoff Wall Sensitivity
Analysis, Station 189+50 to
209+50 Memorandum

40.7 (2007 -
192 kfs)
Meets,

0.17 (CL/ML), 0.10 (CL/ML,

SP/SM, CL/ML)

36.96 200-yr -3.74 Meets

39.96 HTOL -0.74 Meets

NEMDCEL
3030+001 NA Existing Conditions Existing Conditions 2016 ULDC Geotechnical Results Summary Report

41.1 (2016
HTOL) Meets, 0.38 (HTOL)

36.43 200-yr -4.67 Meets

39.43 HTOL -1.67 Meets
1 –Station 3030+00 is 100 feet outside the section of NEMDCEL being certified. This section location was originally the end of the certification reach; however, the subsequent SAFCA construction project extended to Station 3029+00, which became the new boundary for the certification. The cross section at 3030+00 from the PIR and ULDC Geotechnical Results Summary was reviewed and is considered the critical cross section for the certification reach and, therefore, is used for this analysis.
24001006.001A/SAC24R164292 Page 20 of 40 September 12, 2024 © 2024 Kleinfelder
Based on this review the following conclusions can be made:
• Analysis cross sections model underseepage along ARNL (Station 3000+00 to 3051+00) and NEMDCEL (Station 3001+50 to 3029+00) at critical locations. • The 2024 200-year and HTOL WSEs are lower than the WSE modeled in the existing analyses. • The modeled improvements were the same or less conservative than the constructed improvement and met criteria at the analyzed locations.

2.3.1 Swimming Pools
Kleinfelder performed a search of pools located within 100 feet of the subject landside levees toe. No pools were identified along the study area levees.

2.3.2 Conclusion
Based on the above review, it is Kleinfelder’s opinion ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) meet the requirements of ULDC 7.5 Underseepage for Intermittently Loaded Levees.

2.4 ULDC SECTION 7.7 SEISMIC VULNERABILITY
This section contains a summary of the review of the existing reports and analyses performed for opinion ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) as it applies to ULDC Section 7.7 - Seismic Vulnerability for Intermittently Loaded Levees.

The objective of the seismic vulnerability evaluation was to develop information to characterize the potential vulnerability of levee segments during the postulated 200-year return period seismic event.

This information can then be used as a basis to classify the levees in terms of its ability to provide postseismic flood protection in accordance with ULDC. In accordance with the ULDC, post-seismic flood protection requires maintaining a levee crown sufficient for protection against the 10-year flood with 3 feet of freeboard. For intermittently loaded levees (or floodwalls), the ULDC states the following requirement:
24001006.001A/SAC24R164292 Page 21 of 40 September 12, 2024 © 2024 Kleinfelder
“If seismic damage from 200-year-return-period ground motions is expected after the urban level of flood protection is achieved, a post-earthquake remediation plan is required as part of a flood safety plan that is developed in coordination with pertinent local, State, and federal agencies.”
Kleinfelder has been tasked by SAFCA with evaluating the seismic vulnerability of the SAFCA Sacramento area levees located in Sacramento and Sutter Counties, California in support of ULDC levee certification.

As part of that project, Kleinfelder prepared a Seismic Performance Summary Report (Kleinfelder, 2024) that addresses the seismic vulnerability of the North Area Streams study area, which includes the subject portions of the ARNL and NEMDCEL. This report is included in Appendix C of this report.

2.4.1 Conclusion
Based upon the Seismic Performance Summary Report (Kleinfelder, 2024), the ULDC seismic vulnerability classification for ARNL (Stations 3000+00 to 3051+00) and NEMDCEL (Stations 3001+50 to 3029+00) is shown in Table 2.5, below.

Table 2.5
Seismic Vulnerability Classifications for North Area Streams Levees Levee Station Start Station End 2024 Seismic
Vulnerability
ARNL
3000+00 3016+00 Low
3016+00 3044+48 High
3044+48 3051+00 Low

NEMDCEL
3001+50 3011+65 Low
3011+65 3029+00 Low
It is Kleinfelder’s opinion that the subject levee ARNL and NEMDCEL outlined above meets the geotechnical aspects of the Section 7.7 Seismic Vulnerability, except for ARNL Station 3016+00 to 3044+48. As required by the ULDC, a Post Earthquake Remedial Plan is being prepared to address remediation of the ARNL Station 3016+00 to 3044+48 as a result of a seismic event.

2.5 ULDC SECTION 7.8 LEVEE GEOMETRY
This section contains a summary of the existing information for ARNL (Station 3000+00 to 3051+00) and NEMDCEL (Station 3001+50 to 3029+00) with regards to ULDC Section 7.8 Levee Geometry. The ULDC Section 7.8 Levee Geometry is as follows.
24001006.001A/SAC24R164292 Page 22 of 40 September 12, 2024 © 2024 Kleinfelder
“Minimum levee geometry criteria have previously been specified by various USACE and State guidance documents. The guidance for various minimum levee geometry and their references are as follows in Table 7-1.
“For new levees, or levees with extensive reconstruction, situated along major waterways, a minimum 20-foot-wide crown width and 3h:1v waterside and landside slopes (4h:1v waterside slope for bypass levees) is required. Exceptions may be allowed for reconstruction of existing levees where the authorized geometry provides for a steeper slope or narrower crown, the levee has performed well, and it meets stability and seepage criteria. These geometry requirements represent minimum requirements, and wider levee crowns and/or flatter slopes may be necessary in some areas, depending upon geologic and geotechnical considerations. At the same time, however, minimum requirements should be associated with generally uniform, levee materials and homogeneous embankments. Steeper slopes may be allowed in certain circumstances where there is limited space available, and where levees are demonstrated to meet minimum seepage and stability criteria. Steeper waterside levee slopes may be acceptable where stability criteria are met and either slope protection is provided or it is determined that wavewash erosion for a water surface at or below the DWSE could not result in breaching of the levee. For example, levees with slopes steeper than new minimum requirements may be acceptable with elements such as central clay cores, seepage cutoff walls, landside filters or drains, or soil reinforcement that substantially decrease seepage hazards and increase slope stability.

The levee prism should be considered to continue underground based on projection of the aboveground levee slopes. The projected levee slopes are useful for evaluating erosion, excavations, and encroachments near the levee.”
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The ARNL study area levees were initially constructed by local interests in various parts and in various stages, but no records of such construction are available. ARNL was improved in the 1950’s as a part of the USACE Sacramento River Flood Control Project. The levee crest was widened to 20 feet by adding to the waterside of the levee. As discussed in Section 1.2, two cutoff walls were installed along the levee portions of ARNL in 2013 and 2014. The levee was degraded as a working platform for cutoff wall construction approximately 3 feet below the levee crest and reconstructed after cutoff wall construction.

As stated in Section 1.2 NEMDCEL was constructed in the 1930’s with a 10-foot-wide crown, 2H:1V landside slopes, and 3H:1V waterside slopes. In 1996 the levee was raised and widened on the waterside of the levee.

2.5.1 Current Levee Geometry
Psomas provided levee cross sections at select locations along ARNL since no post-construction surveys were available since the construction of the cutoff walls. No surveys of NEMDCEL were performed since the levee geometry has not changed since the 1996 improvements. Kleinfelder visited ARNL (Stations 3000+00 to 30051+00) and NEMDCEL (Stations 3001+50 to 3029+00) and no significant changes to the levee geometry (slope failures, erosion, etc.,) from the previous evaluations were noted. Psomas performed surveys at select locations along ARNL and NEMDCEL. MBK projected the project levee on to the select cross sections to confirm the levee geometry. The figures of the levee geometry analysis is included in Appendix B.

Levee geometry from 2013 and 2023 surveys are summarized in Table 2.6, below.

Table 2.6
ARNL and NEMCEL Levee Crown and Landside Toe Reference Summary Topography
Feature
Elevation Range
(NAVD88, ft) Source Date
ARNL Crown
43 to 451 URS, 2015. “Geotechnical Evaluation Report,
American River Study Area”
2015
43 to 452
MBK, Engineers. “American River North Levee
System: Levee Geometry Analysis (ULDC).

Sheets 5 through 10.
2024
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Table 2.6 (cont.)
ARNL and NEMCEL Levee Crown and Landside Toe Reference Summary Topography
Feature
Elevation Range
(NAVD88, ft) Source Date
ARNL
Landside Toe
25 to 301 URS, 2015. “Geotechnical Evaluation Report,
American River Study Area”
2015
26 to 33.52
MBK, Engineers. “American River North Levee
System: Levee Geometry Analysis (ULDC).

Sheets 5 through 10.
2024

NEMDCEL
Crown 42.5 to 441
Kleinfelder, 2016. “Problem Identification
Report, North Area Streams, SAFCA FEMA Levee
Accreditation (North Area Streams, American
River, Sacramento River Downstream of
American River, and Beach Lake Levee),”
2016

NEMDCEL
Landside Toe 21 - 331
Kleinfelder, 2016. “Problem Identification
Report, North Area Streams, SAFCA FEMA Levee
Accreditation (North Area Streams, American
River, Sacramento River Downstream of
American River, and Beach Lake Levee),”
2016

1. Elevations estimated from plan and profile levee crown and landside toe lines.

2. Elevation range based on survey data performed by Psomas in 2023 on select ARNL cross section locations Station 3000+00, 3004+00, 3007+00, 3011+00, 3018+50, 3026+00, 3030+00, 3034+50, 3040+00, 3044+50, 3047+50, and 3051+00.

Based upon the above data, Kleinfelder makes the following conclusions:
• The ARNL and NEMDCEL levee geometry fits completely within the 2023 surveyed prism.

2.5.2 Conclusion
Therefore, from a geotechnical perspective, the above information is considered applicable and appropriate to provide an adequate assessment of levee geometry for meeting the guidance outlined above for ULDC Section 7.8 Levee Geometry. Therefore, from a geotechnical standpoint (seepage and slope stability), the subject levees are considered to meet ULDC Section 7.8 Levee Geometry.

2.6 ULDC SECTION 7.9 INTERFACES AND TRANSITIONS
This section contains a summary of the review of existing information for ARNL and NEMDCEL with regards to ULDC Section 7.9 Interfaces and Transitions which is defined as follows:
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The civil engineer must consider, evaluate, and explicitly design for interfaces and transitions between different types of levee sections and features along a levee system. Appropriate overlaps, transitions, and connections between features must be evaluated and designed to ensure that the levee system functions holistically, such that no levee reach is more susceptible to problems than an adjacent reach due to gaps in features, loading/demand concentrations, or other threedimensional effects. Such interfaces, transitions, and connections commonly occur at the ends of seepage berms, seepage cutoff walls, revetments, and floodwalls.

Each transition or interface along the ARNL and NEMDCEL is discussed below.

2.6.1 Transition of NEMDCEL Cutoff Wall and ARNL Cutoff Wall Station 2999+70 (ARNL USACE Station 157+00)
Kleinfelder reviewed the as-built drawings (USACE, 2014c) for the ARNL seepage cutoff wall that was installed to a tip of Elevation 10+ feet and beginning at ARNL Station 2999+70 (USACE Station 157+30) heading southeast along ARNL. Another cutoff wall was installed under a separate USACE contract beginning near ARNL Station 3000+00 and continuing north 1,350 feet along NEMDCEL. According to the NEMDCEL cutoff wall as-built documents (USACE, 2014b), the cutoff wall was installed to a minimum tip Elevation of +10 and overlaps the ARNL cutoff wall by 50 feet. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the transition between ARNL and the cutoff wall do not present any gaps, or other threedimensional effects. Therefore, it is Kleinfelder’s opinion that the transition at the cutoff wall meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.2 Transition End of ARNL Cutoff Wall Approximate Station 3013+45 (USACE Station 170+80) and Gravel Drained Toe Berm
Kleinfelder reviewed the as-built drawings for the seepage cutoff wall that ends at approximate Station 3013+45 (Station 170+80). The same as-builts drawings show an approximately 60-foot-long and 10- foot-wide gravel drained toe berm approximately between Stations 3013+10 to 3013+70 (USACE Stations 170+47.75 and 171+10) as a transition between the end of the seepage cutoff wall and the Del Paso Stoplog structure. The drain toe berm was constructed with an 8-inch-thick sand filter below levee toe and 3-feet vertically along the ARNL landside slope. According to as-built drawings the drained toe berm overlaps the cutoff wall by approximately 40 feet. Previously performed seepage and stability 24001006.001A/SAC24R164292 Page 26 of 40 September 12, 2024 © 2024 Kleinfelder
analysis performed with the gravel drained toe berm and without the cutoff wall meet criteria at a higher WSE than the 2024 WSEs. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the transition between ARNL and the cutoff wall do not present any gaps, or other threedimensional effects. Therefore, it is Kleinfelder’s opinion that the transition at the cutoff wall to the gravel drained toe berm meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.3 Transition End of ARNL and Gravel Drained Toe Berm Approximate Station 3013+70 (USACE Station 171+10) to Del Paso Stoplog Structure Northwest Wall and Del Paso Stoplog Structure Southeast Wall to ARNL Approximate Station 3014+40 (USACE Station 171+75) Kleinfelder reviewed the as-built drawings for the approximately 60-foot-long and 10-foot-wide gravel drained toe berm approximately between Stations 3013+10 to 3013+70 (USACE Stations 170+47.75 and 171+10). As a part of the ARNL DDR (KGJV, 2012a), KGJV reviewed the Del Paso Blvd stoplog structure 1932 as-builts and subsurface conditions. The findings were documented in a technical memorandum (KGJV, 2012d) included as an attachment to the DDR. Seepage and stability analyses were performed along the interfaces between the ARNL and the Del Paso Blvd Stoplog walls at approximate Stations 3013+55 (USACE Station 170+90) and 3014+40 (USACE Station 171+75). The analysis met criteria at a higher WSE than the 2024 WSE. Kleinfelder visited the site and did not note any significant damage or erosion around the interfaces. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the transition between ARNL and the Del Paso stoplog structure do not present any gaps, or other three-dimensional effects. Therefore, it is Kleinfelder’s opinion that this meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.4 Transition of ARNL Approximate Station 3015+60 to UPRR Stoplog Structure Northwest Wall and Southeast Wall to ARNL Approximate Station 3016+00
In 1990’s, USACE constructed the stoplog structure (Spink, 1997). As a part of the ARNL DDR (KGJV, 2012a), KGJV reviewed the UPRR stoplog structure and documented the review in a technical memorandum (KGJV, 2012c) included as an attachment to the DDR. Kleinfelder reviewed the 1997 UPRR stoplog structure as-builts and the 2012 UPRR stoplog structure memorandum. Additionally, Kleinfelder performed additional seepage and stability analysis at approximate Station 3014+40 (USACE Station 24001006.001A/SAC24R164292 Page 27 of 40 September 12, 2024 © 2024 Kleinfelder
171+75) and at approximate Station 3018+70 (USACE Station 176+00) located along the ARNL embankment. The analysis met criteria at a higher WSE than the 2024 WSE. Kleinfelder visited the site and did not note any significant damage or erosion around the interfaces. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the transition between ARNL and the UPRR stoplog structure do not present any gaps or other three-dimensional effects. Therefore, it is Kleinfelder’s opinion that the transitions between ARNL and the UPRR stoplog structure walls meet the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.5 Interface of UPRR Trestle Bridge Piles Between Approximate Stations 3015+60 to 3016+00 Kleinfelder performed a site visit in December 2023 and observed the UPRR tracks supported by a wooden trestle bridge approximately between Stations 3015+60 to 3016+00. The tracks cross the American River where the northern bridge abutment is located on the landside slope of ARNL. The bridge bents are approximately 20 feet wide and consist of a group of five 2-foot diameter wooden piles. The piles are increasingly buried into the ARNL waterside toe and slope as the tracks cross ARNL.

No as-built drawings were found as a part of the document review. It is assumed the bridge was constructed in the late 1800’s to early 1900’s prior to the construction of ARNL. Explorations perform within the UPRR tracks show the material is consistent with the surrounding soils. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and topography the presence of the bridge piles do not present a gap. Therefore, it is Kleinfelder’s opinion that the UPRR trestle bridge piles interfaces meet the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.6 Interface of Highway 160 Bridges Support Columns and Northern Abutment Between Approximate Stations 3016+40 to 3018+00
Kleinfelder performed a site visit in December 2023 and observed the support columns of the Highway 160 north and southbound bridges penetrating the waterside toe and slope of ARNL approximately between Stations 3016+40 to 3018+00. The Highway 160 bridges cross the American River where the northern bridge abutment is located on the landside slope of ARNL. The bridge is supported by concrete rectangular column pairs spaced approximately every 50-feet. According to a 2013 Caltrans foundation report, the bridges were constructed in 1946. The bents are supported on 10-foot square spread 24001006.001A/SAC24R164292 Page 28 of 40 September 12, 2024 © 2024 Kleinfelder
footings to Elevation 8 feet (datum not defined) and bridge abutments are supported with driven steel piles. The ARNL landside toe is raised approximately 10 feet at this location due to the 160 bridges abutments. Explorations performed within the UPRR embankment show the material is consistent with the surrounding soils. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and topography the presence of the bridge piles do not present a gap. Therefore, it is Kleinfelder’s opinion that the Highway 160 bridges support columns and northern abutment interfaces meet the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.7 Transition Start of ARNL Cutoff Wall Approximate Station 3019+20 (ARNL USACE Station 176+50) Kleinfelder reviewed the as-built drawings for the seepage cutoff wall that was installed to tip Elevation +5 feet beginning at approximately ARNL Station 3019+20 (USACE Station 176+50) heading upstream (southeast) along ARNL. The cutoff wall overlaps with the Highway 160 bridge abutment embankment along the ARNL landside toe. Seepage and stability analyses were previously performed that modeled existing conditions without levee improvements (i.e., cutoff wall) at USACE Stations 176+00 and 183+60.

Both cross section locations met seepage criteria. USACE Station 183+60 did not meet stability criteria without a cutoff wall and USACE Station 176+00 met stability criteria without a cutoff wall. Comparison between the analysis performed at USACE Station 183+60 versus 176+00 shows the materials properties and stratigraphy are identical for seepage and stability. The only difference between the models is the landside toe Elevations are +32 and +28 for USACE Stations 176+00 and 183+60, respectively. The raised levee toe corresponds with the Highway 160 bridges abutment embankment, which acts as a stability berm that raises the factor of safety. According to the as-built drawings for the seepage cutoff wall (USACE, 2014a), the seepage cutoff wall extends into the raised landside toe embankment by 200-feet.

The USACE Station 176+00 analysis met criteria at a higher WSE than the 2024 WSE. No past performance issues have been noted at this location.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the transition between ARNL and the seepage cutoff wall do not present any gaps, or other three-dimensional effects. Therefore, it is Kleinfelder’s opinion that the transition at the cutoff wall meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions. 24001006.001A/SAC24R164292 Page 29 of 40 September 12, 2024 © 2024 Kleinfelder

2.6.8 Transition of ARNL Cutoff Wall Approximate Station 3052+30 (USACE Station 209+50) Kleinfelder reviewed the as-built drawings (USACE, 2014a) for the end of the ARNL seepage cutoff wall at ARNL Station 3052+30 (USACE Station 209+50) that was installed to tip Elevation -5. Another cutoff wall was previously installed under a separate USACE contract beginning at approximate Station 3051+30 (USACE Station 208+50) to tip Elevation -14.4 and continued upstream. According to the cutoff wall as-built documents (USACE, 2014b), the cutoff walls overlap by 100 feet. Seepage and stability analysis performed at USACE Station 201+80 was modeled with a cutoff wall at Elevation +0 and met criteria for a higher WSE than the 2024 WSEs.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the transition between ARNL and the cutoff wall do not present any gaps, or other threedimensional effects. Therefore, it is Kleinfelder’s opinion that the transition meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.9 Interface of UPRR Embankment on NEMDCEL Landside Slope Stations 3001+50 to 3029+00 The UPRR embankment spans the entire length of NEMDCEL from Station 3001+50 to 3029+00. The embankment is estimated to be constructed in the late 1800’s or early 1900’s prior to the levee construction in the 1930’s. The embankment is believed to be constructed with local materials similar to the materials used to construct NEMDCEL. The UPRR embankment is approximately 9 feet below the NEMDCEL crest and has a landside slope between 2H:1V and 3H:1V. The UPRR embankment geometry was included in the seepage and stability analysis which met criteria. During the December 2023 site visit, no significant issues were observed (i.e., erosion or changes to the embankment configuration. No past performance issues have been noted along this interface.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the interface of the UPRR embankment does not present any gaps, or other three-dimensional effects. Therefore, it is Kleinfelder’s opinion that the transition meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.10 Interface of NEMDCEL/UPRR landside Toe Ditch 3001+50 to 3013+00 A landside shallow unlined v-ditch spans NEMDCEL along the UPRR landside toe between Stations 3001+50 and 3013+00. The ditch invert is approximately between El +16 and +15 which is approximately 5 to 10 feet below NEMDCEL landside toe. During construction of the waterside NEMDCEL levee raise, a 24001006.001A/SAC24R164292 Page 30 of 40 September 12, 2024 © 2024 Kleinfelder
keyway trench was excavated and inspected for sands and unstable materials. The keyway trench depth plotted on the PIR (Kleinfelder, 2016a) is deeper for most of the ditch. No past performance issues have been noted along this interface.

Based on review of the existing site conditions, past performance history, and seepage and stability analyses, the interface of the landside toe ditch does not present any gaps, or other three-dimensional effects. Therefore, it is Kleinfelder’s opinion that the transition meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.11 Interface of NEMDCEL to City of Sacramento Pumping Plant No. 153 at Station 3014+00 Pump Station No. 153 is located to the landside of the railroad embankment at Station 3014+00 (USACE Station 144+30). According to the record drawings (Spink, 1996) one, 36-inch welded steel pipe runs over the levee at Elevation 34.2 feet (NAVD88). The pipe exits on the waterside in a concrete headwall and a flap gate to prevent backflow. The pipes passes through a concrete vault located in a vault on the waterside of the levee crest that contains a siphon breaker valve.

Based on review of the existing site conditions and past performance history, the transition between NEMDCEL and Pumping Plant No. 153 does not present any gaps, or other three-dimensional effects.

Therefore, it is Kleinfelder’s opinion that the transition meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.12 Interface of NEMDC East Levee to West El Camino Avenue Floodwalls and Bridge at Station 3021+75
The existing floodwall and closure structure at West El Camino Avenue were removed and a new floodwall was constructed as part of the City of Sacramento (West) El Camino Avenue Bridge Replacement Project in 2008. This was done under Permit No. 18175. According to the record drawings, (Dokken, 2007) the short floodwall segments on the north and south side of the El Camino bridge allow for a ramp from the levee crest to West El Camino Avenue. The record drawings show the flood walls foundations are 3 to 5 feet below grade and 5 to 7-foot wide. The flood walls vary in height up to 6 feet maximum height. The West El Camino Avenue bridge abutment and a set of approximately 3-foot diameter pier bents are in the waterside slope of NEMDCEL.

Based on review of the existing site conditions and past performance history, the transition between NEMDCEL and the ARNL and the West El Camino Avenue floodwall structure and bridge do not present 24001006.001A/SAC24R164292 Page 31 of 40 September 12, 2024 © 2024 Kleinfelder
any gaps, or other three-dimensional effects. Therefore, it is Kleinfelder’s opinion that the transition meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.13 Interface of NEMDCEL Telecommunications Vault Station 3025+00 A telecommunications vault is located on the landside of the levee near the levee crest at about Station 3025+20. This vault and utility crossing was constructed under Reclamation Board Permit 5181. The conduits are shown to cross the levee crest at about Elevation 35.3. According to the permit, the installation included conduits that were encased in concrete on the waterside of the levee and a concrete cutoff wall (7 feet 10 inches by 8 feet 6 inches) was built where the conduits crossed beneath the levee crown.

Based on review of the existing site conditions and past performance history, the transition between NEMDCEL and the telecommunications vault and conduit do not present any gaps, or other threedimensional effects. Therefore, it is Kleinfelder’s opinion that the transition meets the geotechnical requirements of the ULDC 7.9 Interfaces and Transitions.

2.6.14 Conclusion
Based upon the above information, it is Kleinfelder’s opinion that the above interfaces and transitions meet the geotechnical requirements of ULDC (DWR, 2012) Section 7.9 Interfaces and Transitions.

2.7 ULDC SECTION 7.14 FLOODWALLS, RETAINING WALLS, AND CLOSURE STRUCTURES There are floodwalls on either side of W El Camino Avenue located along NEMDCEL. One closure structure is located at W El Camino Avenue along NEMDCEL. Two closure structures are located along ARNL with one at Del Paso Avenue at Station 3014+00 and one at the UPRR crossing at Station 3018+00.

This evaluation includes review of the construction details of specific structures in relation to the geotechnical aspects of slope stability and seepage as applicable to current ULDC criteria. This evaluation has not included performance of new analysis or field investigation. Where available, construction inspection records have also been reviewed. 24001006.001A/SAC24R164292 Page 32 of 40 September 12, 2024 © 2024 Kleinfelder

2.7.1 Del Paso Boulevard Closure Structure
Kleinfelder visited the site in 2023 and has previously evaluated the closure structure in 2012 (KGJV, 2012d). The construction of this closure structure was evaluated for geotechnical considerations related to slope stability and seepage at the transition from the levee to the Del Paso Closure Structure during a flood event. The cutoff wall to the west (north) has a tip elevation of +15 and ends 34 feet before the opening in the Del Paso Closure Structure. The structure penetrates the blanket to an elevation of approximately +17 feet. A cutoff wall was not constructed to the east (south) of the closure structure. A cross section was taken of the Del Paso Closure Structure and evaluated for seepage and slope stability.

As-Built drawings of the closure structure show a 1.5 feet thick reinforced concrete cutoff wall extends

10.4 feet below the top of the pavement. Soil borings performed in the closure structure showed 12 inches of concrete supported on 7.5 feet of silt, underlain by lean clay to a depth of 21 feet. A site visit was performed to observe the structure and the existing seepage and stability evaluations were reviewed. These structures have been in place since 1933; therefore, it is unlikely these structures will induce additional settlement of the underlying levee embankment. Based on the above, it is Kleinfelder’s opinion that these interfaces meet the geotechnical requirements of the ULDC for seepage and slope stability.

2.7.2 UPRR Stoplog Structure
Kleinfelder visited the site in 2023 and has previously evaluated stoplog structure in 2012 (KGJV, 2012c).

The construction of this closure structure was evaluated for geotechnical considerations related to slope stability and seepage at the transition from the levee to the UPRR closure structure during a flood event.

A cross section was taken and evaluated for slope stability and seepage in 2012 to analyze this levee feature. Reviewing the As-Built documents for this structure show that an 8-inch thick “grade beam” or “cutoff grade beam” extends 2 feet below the bottom of the railroad ties between the UPRR stoplog structure’s retaining walls. Two borings were completed at that time and encountered sandy lean clay from the levee crown to the footing of the stoplog structure and below that encountered silts consistent with levee fill material. A site visit was performed to observe the structure and the existing seepage and stability evaluations were reviewed. These structures have been in place since at least 1997; therefore, it is unlikely these structures will induce additional settlement of the underlying levee embankment.

Based on the above, it is Kleinfelder’s opinion that these interfaces meet the geotechnical requirements of the ULDC for seepage and slope stability.
24001006.001A/SAC24R164292 Page 33 of 40 September 12, 2024 © 2024 Kleinfelder

2.7.3 West El Camino Avenue Floodwalls
The existing floodwall and closure structure at West El Camino Avenue were removed and new floodwalls were constructed as part of the City of Sacramento (West) El Camino Avenue Bridge Replacement Project in 2008. This was done under Permit No. 18175. According to the record drawings, (Dokken, 2007) the short floodwall segments on the north and south side of the El Camino bridge allow for a ramp from the levee crest to West El Camino Avenue. The record drawings show the flood walls foundations are 3 to 5 feet below grade and 5 to 7-foot wide. The flood walls vary in height up to 6 feet maximum height. The construction of the floodwalls were evaluated for geotechnical considerations related to slope stability and seepage at the transition from the levee to the floodwall during a flood event. These structures have been in place since 2007; therefore, it is unlikely these structures will induce additional settlement of the underlying levee embankment. Kleinfelder visited the site in December 2023 and evaluated the floodwalls. It is Kleinfelder’s opinion that these interfaces meet the geotechnical requirements of the ULDC for seepage and slope stability.

2.7.4 Conclusion
Based upon the above data, Kleinfelder makes the following conclusions pertaining to ULDC 7.14 Floodwalls, Retaining Walls, and Closure Structures:
• Del Paso closure structure meets the geotechnical requirements of the ULDC for settlement, seepage and slope stability
• UPRR closure structure meetsthe geotechnical requirements of the ULDC for settlement, seepage and slope stability
• West El Camino Avenue floodwalls meet the geotechnical requirements of the ULDC for settlement, seepage and slope stability
24001006.001A/SAC24R164292 Page 34 of 40 September 12, 2024 © 2024 Kleinfelder
3 AMERICAN RIVER NORTH LEVEE STUDY AREA SUMMARY OF RESULTS ___________________________________________________________________________________ Based on the review summarized in Section 2, above, Table 3.1 includes those reaches that in Kleinfelder’s opinion meet or do not meet the geotechnical aspects of the ULDC (DWR, 2012) for Sections 7.3 Soil Sampling, Testing, and Logging, 7.4 Slope Stability, 7.5 Underseepage, 7.7 Seismic Vulnerability, and 7.9 Interfaces and Transitions.

Table 3.1
Levee Reaches That Meet Geotechnical Aspects of ULDC Criteria Project
Levee
Approximate Levee
Stationing
Meets
Criteria
Does Not
Meet
Criteria
ULDC Criteria Section
ARNL 3000+00 to 3051+00 X

7.3 Soil Sampling, Testing, and
Logging

7.4 Slope Stability

7.5 Underseepage

7.8 Levee Geometry

7.9 Interfaces and Transitions

7.14 Floodwalls, Retaining Walls,
and Closure Structures
ARNL 3000+00 to 3051+00 X 7.7 Seismic Vulnerability
NEMDCEL 3001+50 to 3029+00 X

7.3 Soil Sampling, Testing, and
Logging

7.4 Slope Stability

7.5 Underseepage

7.7 Seismic Vulnerability

7.8 Levee Geometry

7.9 Interfaces and Transitions

7.14 Floodwalls, Retaining Walls,
and Closure Structures
It is Kleinfelder’s opinion that the subject levee ARNL outlined above meets the geotechnical aspects of the ULDC as outlined in Table 3.1, above, except for 7.7 Seismic Vulnerability. As required by the ULDC, a Post Earthquake Remedial Plan is being prepared to address remediation of the ARNL as a result of a seismic event.

It is Kleinfelder’s opinion that the subject levee NEMDCEL outlined above meet the geotechnical aspects of the ULDC as outlined in Table 3.1, above.
24001006.001A/SAC24R164292 Page 35 of 40 September 12, 2024 © 2024 Kleinfelder
4 LIMITATIONS
___________________________________________________________________________________ This work was performed in a manner consistent with that level of care and skill ordinarily exercised by other members of Kleinfelder’s profession practicing in the same locality, under similar conditions and at the date the services are provided. The work performed was based on project information provided by client. Kleinfelder’s conclusions, opinions, and recommendations are based on a limited number of observations and data. It is possible that conditions could vary between or beyond the data evaluated.

Kleinfelder makes no other representation, guarantee, or warranty, express or implied, regarding the services, communication (oral or written), report, opinion, or instrument of service provided.

This report may be used only by the client and the registered design professional in responsible charge and only for the purposes stated for this specific engagement within a reasonable time from its issuance, but in no event later than two years from the date of the report.

The scope of services was limited. 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 the information presented herein.

Although risk can never be eliminated, more detailed and extensive studies yield more information, which may help understand and manage the level of risk.

All rivers, streams and lakes will flood eventually. This fact means that all levees will be called upon to combat floodwaters at some point. Levees reduce the risk of flooding. But no levee system can eliminate all risk of flooding. The term “certification” is not intended to provide a guarantee or warranty of the conditions of the levee or its performance and assumes the following 1) a certification by a registered professional engineer or other party does not constitute a warranty or guarantee of performance, expressed or implied; 2) certification of data is a statement that the data is accurate to the best of the certifier’s knowledge; and 3) certification of analyses is a statement that the analyses have 24001006.001A/SAC24R164292 Page 36 of 40 September 12, 2024 © 2024 Kleinfelder
been performed correctly and in accordance with sound engineering practices. A levee certification does not address or mitigate the inherent flood risk proposed to a particular community. 24001006.001A/SAC24R164292 Page 37 of 40 September 12, 2024 © 2024 Kleinfelder
5 REFERENCES
___________________________________________________________________________________ Department of Water Resources, California, 2012. “Urban Levee Design Criteria, State of California, Department of Water Resources.” Dated May 2012.

Department of Water Resources, California, 2015. “Guidance Document for Geotechnical Analyses, Urban Levee Geotechnical Evaluations Program.” Dated April 27, 2015.

Department of Water Resources, California, 2022. “SGMA Data Viewer, Groundwater Levels.” https://sgma.water.ca.gov/webgis/?appid=SGMADataViewer#gwlevels/. Accessed January 28, 2022.

Dokken Engineering, 2006. “Improvement Plans for (West) El Camino Avenue Bridge Replacement, Sacramento, California.” Dated August 23, 2007.

Kleinfelder, 1995. “Geotechnical Evaluation of Levee Improvements, Natomas East Main Drainage Canal, Unit 3-East Levee, Sacramento, California.” Dated April 27, 1995.

Kleinfelder, 1997. “Final Report, Field Compaction Test Results, NEMDC 2B/3B, Sacramento, California.” Compaction testing summary. Dated February 13, 1997.

Kleinfelder, 2009. “Seepage and Slope Stability Report, American River Common Features, River Mile 2.0 to 3.6, Sacramento, California.” Dated August 7, 2009.

Kleinfelder, 2013. “Geotechnical Data Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee),”. Dated May 31, 2013.

Kleinfelder, 2016. “Problem Identification Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee),”. Dated September 18, 2013. Revised April 29, 2016.

Kleinfelder, 2016. “ULDC Geotechnical Results Summary, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee),”. Dated April 26, 2016.
24001006.001A/SAC24R164292 Page 38 of 40 September 12, 2024 © 2024 Kleinfelder
Kleinfelder, 2019. “Draft Seepage and Slope Stability Evaluation for 115,000 CFF WSE, Del Paso Boulevard to UPRR Tracks, USACE Project Station 171+50 to 173+00, American River North Levee, Sacramento, California.” Dated April 11, 2019.

Kleinfelder, 2024. “Seismic Performance Summary Report North Area Streams Levee Areas, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento County, California.” Dated February 12, 2024. Revised September 10, 2024.

KGJV (Kleinfelder Geomatrix Joint Venture), 2012a. “Final Design Document Report, American River Common Features, American River North Levee, River Mile 2.0 to 3.6,”. Dated August 20, 2012. (Select design memorandum and reports included in the DDR referenced below) KGJV, 2010. “Remediation Methods Development, American River Common Features, River Mile

2.0 to 3.6,”. Dated December 20, 2010.

KGJV, 2012b. “Subsurface Profile Evaluation Based on Additional Data and Cutoff Wall Sensitivity Analysis, Sation 189+50 to Station 209+50, American River Common Features River Mile

2.0 to 3.6,” KGJV Memorandum. Dated March 7, 2012.

KGJV, 2012c. “Seepage Evaluation, UPRR Stoplog Structure, Station 173+15, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated March 7, 2012.

KGJV, 2012d. “Seepage Evaluation, Del Paso Boulevard Closure Structure, Station 171+20, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated March 7, 2012.

KGJV, 2012e. “Seepage and Slope Stability Evaluation, Del Paso Tie-In, Station 170+40 to 171+10, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum.

Dated March 8, 2012.

KGJV, 2012f. “Seepage and Slope Stability Evaluation, Del Paso Boulevard to UPRR Tracks, Station 171+50 to 173+00, American River Common Features RM 2 to 3.6,” KGJV Memorandum. Dated March 14, 2012.

KGJV, 2012g. “Cutoff Wall Sensitivity Analysis, Station 176+00 to Station 189+50, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated March 23, 2012.

KGJV, 2012h. “Filter Criteria Check for Gravel Berm, Station 170+40 to 171+10, American River Common Features River Mile 2.0 to 3.6,” KGJV Memorandum. Dated June 29, 2012. 24001006.001A/SAC24R164292 Page 39 of 40 September 12, 2024 © 2024 Kleinfelder
KGJV, 2012i. “Cutoff Wall Sensitivity Analysis, Station 157+00 to Station 170+80,” KGJV Memorandum. Dated October 13, 2011. Revised July 9, 2012.

KGJV, 2012j. “American River Common Features (Remaining Sites) WRDA 99 – NEMDC South.” As-built drawings Contract No. W91238-12-C-0041. File Date July 3, 2012.

MBK, Engineers. “American River North Levee System – Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee.

Dated July 1, 2024.

Mead & Hunt, 2024. “American North Levee System, Due Diligence Review for ULDC Certification.” Project Number R1941500-120265.09. Dated September 2024.

Spink Corporation, 1997. “NEMDC East Levee Improvements, Unit 3B.” Sacramento Area Flood Control Agency. As-Built Drawings Sheets L-18, S-7, S-8 for UPRR and Del Paso Stoplog Structure. Dated May 5, 1997.

Spink Corporation, 1996. “Natomas East Main Drainage Canal, Units 2B & 3B, Levee Improvement Project, (American River to West El Camino Avenue – Unit 2B), (American River to 1800’ North of Arcade Creek – Unit 3B), Sacramento Area Flood Control Agency Project Plans for Construction of Natomas Area Flood Control Improvement Project, Sacramento, California.” Record Drawings. As-Built Date May 13, 1996.

State of California, 2008. Title 23, California Code of Regulations.

United States of America. Title 44 of the Code of Federal Regulations (44 CFR) Section 65.10 URS, 2009. “Phase 1 Geotechnical Data Report, NEMDC East Study Area.” Prepared for Department of Water Resources by URS. Dated 2009.

URS, 2011. “Supplemental Geotechnical Data Report, NEMDC East Study Area.” Prepared for Department of Water Resources by URS. Dated 2011.

USACE, 2014a. “American River Common Features, (Remaining Sites), WRDA 99 – NEMDC South, Sacramento County, California, Contract No. 13-C-0019 As-Builts.” Dated July 3, 2012. As-Built Date January 9, 2014.
24001006.001A/SAC24R164292 Page 40 of 40 September 12, 2024 © 2024 Kleinfelder
USACE, 2014b. “American River Common Features, (Remaining Sites), WRDA 99 – NEMDC Extension, Sacramento County, California, Contract No. W91238-15-C0003 As-Builts.” Dated March 3, 2014. As-Built Date not provided. Received with as-built records February 8, 2024.

USACE, 2014c. “American River Common Features, (Remaining Sites), WRDA 99 – NEMDC North, Sacramento County, California, Contract No. W91238-12-C0041 As-Builts.” Dated June 1, 2013.

As-Built Date October 24, 2014.

URS 2015a, “Geotechnical Evaluation Report, American River Study Area, Urban Levee Evaluations Project, Contract 4600008101.” Prepared for Department of Water Resources by URS. Dated January 2015.

URS, 2015b, “Geotechnical Evaluations Report, Volume 1, Existing Conditions, NEMDC East Study Area, Urban Levee Evaluations Project.” Prepared for Department of Water Resources by URS. Dated March 2015.

URS, 2015c, “Geotechnical Evaluations Report, Volume 2, Remedial Alternatives, NEMDC East Study Area, Urban Levee Evaluations Project.” Prepared for Department of Water Resources by URS.

Dated March 2015.

USACE 2000, “Design and Construction of Levees,” US Army Corps of Engineers, Engineer Manual, EM 1110-2-1913, April 30, 2000.

USACE 2005, “Design Guidance for Levee Underseepage,” US Army Corps of Engineers, Technical Letter ETL 1110-2-569, May 1, 2005.

USACE, 2000. “Design and Construction of Levees,” US Army Corps of Engineers, Engineer Manual, EM 1110-2-1913. Dated April 30, 2000.

USACE, 2005. “Design Guidance for Levee Underseepage,” US Army Corps of Engineers, Technical Letter ETL 1110-2-569. Dated May 1, 2005.

USACE, 2022. “CESPK-EDG, SOP 3 Geotechnical Levee Practice, May 2022, Standard Operating Procedure 3, Geotechnical Levee Practice, US Army Corps of Engineers, Sacramento District, Geotechnical Engineering Branch.” Dated May 2022.

FIGURES
______________________________________________________________________________________________

LIST OF ATTACHMENTS
Figure 1 ARNL and NEMDCEL Site Vicinity Map
Figure 2 ARNL and NEMDCEL Site Location Map
Site

AMERICAN RIVER NORTH LEVEE

NEMDC EAST LEVEE

SITE VICINITY MAP
PROJECT:

FILE NAME:

FIGURE
1 DRAWN:

CHECKED BY:

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.

DRAWN BY:
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Levee Alignment
SACRAMENTO, CA FILE: \\azrgisstorp03\GIS_Projects\Client\SAFCA\24001006.001A-SeismicPerformanceSumReport\MXD\F1_ARN_SiteLocation.mxd

ULDC FINDING AND FEMA LEVEE

CERTIFICATION PROGRAM

SACRAMENTO AREA FLOOD CONTROL

AGENCY LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
Service Layer Credits: Copyright:© 2013 National Geographic Society, i-cubed; ESRI World Imagery, Maxar Vivid Advanded image dates 4/12/2022, 4/26/2022, and 5/4/2022; SACOG
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4/26/2022, and 5/4/2022; SACOG Orthos image date
3/18/2022.
0 500 1,000
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Locations are Approximate £
3000+00

ULDC FINDING AND FEMA LEVEE

CERTIFICATION PROGRAM

SACRAMENTO AREA FLOOD CONTROL

AGENCY LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA

AMERICAN RIVER NORTH LEVEE

NEMDC EAST LEVEE

LOCATION MAP
Updated 8/30/2024: S. Day
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APPENDIX A
___________________________________________________________________________________

LIST OF ATTACHMENTS
MBK, Engineers. “American River North Levee System – Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee. Dated July 1, 2024.

Water Resources  Flood Control  Water Rights

TECHNICAL MEMORANDUM
DATE: July 1, 2024
PREPARED FOR: SAFCA
PREPARED BY: Michael Archer, P.E.

REVIEWED BY: Don Trieu, P.E.

SUBJECT: American River North Levee System - Determination of the Urban Levee Design Criteria Design Water Surface Elevation, Minimum Top of Levee, and Hydraulic Top of Levee

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 2 2 Acronyms and Abbreviations
1-D one dimensional
2-D two dimensional
AEP annual exceedance probability
ARN American River north
cfs cubic feet per second
CVFED Central Valley Floodplain Evaluation and Delineation CVFPP Central Valley Flood Protection Plan
CVHS Central Valley Hydrology Study
DWR California Department of Water Resources
DWSE Design Water Surface Elevation
FEMA Federal Emergency Management Agency
HTOL Hydraulic Top of Levee
LAR Lower American River
MBK MBK Engineers
MTOL Minimum Top of Levee
NAS North Area Streams
NAVD88 North American Vertical Datum of 1988
NEMDC Natomas East Main Drainage Canal
RM River Mile
SAFCA Sacramento Area Flood Control Agency
SNRR Sacramento Northern Railroad
SVRP Seismic Vulnerability Restoration Profile
ULDC Urban Levee Design Criteria
ULOP Urban Level of Flood Protection
UPRR Union Pacific Railroad
USACE U.S. Army Corps of Engineers
WSE water surface elevation

1. Purpose
The Sacramento Area Flood Control Agency (SAFCA) is in the process of evaluating the levees within its jurisdictional boundaries for compliance with the State of California’s Urban Levee Design Criteria (ULDC) (DWR, 2012). This technical memorandum provides documentation of the determination of the hydraulic parameters listed in Table 1, which are necessary for the ULDC compliance evaluation of the American River North (ARN) levee system.

All elevations are referenced to the North American Vertical Datum of 1988 (NAVD88).

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 3 Table 1. ULDC Hydraulic Parameters
Parameter ULDC Definition
Design Water Surface Elevation (DWSE) Median 200-year water surface elevation (WSE) Minimum Top of Levee (MTOL)
DWSE plus the higher of
• 3 feet, or
• wind setup and wave runup
Hydraulic Top of Levee (HTOL)
The lower of
• DWSE plus 3 feet, or
• Median 500-year WSE
Seismic Vulnerability Restoration Profile (SVRP)
10-year water surface elevation plus the higher of
• 3 feet, or
• wind setup and wave runup

2. Study Area
The American River North (ARN) levee system protects the floodplain bounded on the south by the American River, on the west by the Natomas East Main Drainage Canal (NEMDC), on the north by Arcade Creek, and on the east by high ground (see Figure 1). The levee system is made up of the three levee segments summarized in Table 2.

Table 2. American River North Levee System
Levee Segment Length (feet) Upstream Limit Downstream Limit American River north levee 54,850 Arden Way NEMDC east levee Arcade Creek south levee 11,000 Marysville Blvd. NEMDC east levee NEMDC east levee 6,512 Arcade Creek south levee American River north levee Figure 1. American River North Levee System
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 4

3. Hydrology
Central Valley Hydrology Study (CVHS) procedures and hydrologic data were used in this analysis. The CVHS was commissioned by DWR and prepared by the USACE (USACE, 2015). For the Sacramento River and San Joaquin River basins, the CVHS defines a procedure in which a scaled flood event with a pattern based on a historical flood event is selected to represent the flood of a specific frequency at a specific location, or centering. The CVHS also developed hydrologic data for several smaller ungaged watersheds, including the Natomas-Area Stream Group, which includes Dry Creek, Robla Creek and Arcade Creek (USACE, 2013). The hydrologic data for the Natomas-Area Stream Group was developed for discrete Nyear flood frequencies with centerings defined by contributing area (C) parameters. The Natomas-Area Stream Group hydrologic data was updated by USACE in 2019. There are four CVHS defined flood centerings that influence the NAS model study area:
• Natomas-Area Stream Group: Dry Creek
• Natomas-Area Stream Group: Robla and Magpie Creeks
• Natomas-Area Stream Group: Arcade Creek
• Sacramento River Basin: American River at Fair Oaks and Latitude of Sacramento The ULDC requires the computation of water surface elevations for the 10-year, 200-year, and 500-year flood events. The Sacramento River Basin scaled flood events and Natomas-Area Stream Group C parameters for these flood frequencies and flood centerings are summarized in Table 3. The final computed maximum WSE is the composite maximum of the maximum WSE’s computed for the four flood centerings.

The County of Sacramento’s D-15 pump station, at the upstream end of the modeled NEMDC reach, is an inline pump station with gates (County of Sacramento, 2007). During large flood events the gates close automatically when the water surface elevation at the pump station reaches a pre-defined trigger elevation, preventing backwater due to high flows in Dry and Robla creeks from affecting flood stages north of the pump station. After the gates close, the pumps will automatically turn on to ensure positive flow from north to south. The station has three 333 cfs capacity pumps. The operation criteria specify a firm capacity based on use of two of the three pumps, keeping one for a backup. However, all three pumps may be operated concurrently if required. For the ULDC analysis, the conservative assumption of a three-pump operation, with a total flow of 999 cfs, was used.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 5 Table 3. CVHS Flood Events
Flood Centering
Flood
Frequency
(Recurrence
Interval)
Watershed
North Area Streams Sacramento River
Dry Creek 10-year 10yr_C=99.5 1 1995-60% 2, 3
200-year 200yr_C=99.5 1 1995-105% 2
500-year 500yr_C=99.5 1 1995-120% 2
Robla-Magpie Creeks 10-year 10yr_C=RIOLINDA_MAGPIE 1 1995-60% 2, 3 200-year 200yr_C=RIOLINDA_MAGPIE 1 1995-105% 2
500-year 500yr_C=RIOLINDA_MAGPIE 1 1995-120% 2
Arcade Creek 10-year 10yr_C=ARC 1 1995-60% 2, 3
200-year 200yr_C=ARC 1 1995-105% 2
500-year 500yr_C=ARC 1 1995-120% 2
Fair Oaks-latitude of
Sacramento 10-year 1986-55% 2 1986-55% with 40% on American R. 1, 2 200-year 1986-110% 2 1986-110% with 125% on
American R. 2
500-year 1986-100% 4 1986-100% with 176% on
American R. 4
1 Data ID from USACE 2019 updated hydrologic data set.
2 Event selection by USACE (USACE, 2019). “1995-60%” = 1995 flood pattern with a 60% scale factor. 3 CVHS hydrologic data does not include the 1995-60% flood event. The closest available flood event data, 1995-75%, was used in the analysis. The 1995-75% data approximately represents the 20-year flood event. 4 Event selection by USACE (USACE, 2020).

4. Hydraulic Model
Four HEC-RAS1 hydraulic models were used to determine the ULDC water surface elevations for the American River North levee system:

1. Lower American River (LAR) model

2. North Area Streams (NAS) model

3. Sacramento River system model, 2019 version

4. Sacramento River system model, 2016 version
1 HEC-RAS is software developed by the USACE Hydrologic Engineering Center for the purpose of performing one-dimensional (1-D) and two-dimensional (2-D) hydraulic calculations for a full network of natural and constructed channels (USACE, 2023a).

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 6 The four models were used to leverage previously developed models and minimize the need for new model development.

4.1. Lower American River (LAR) Model
The LAR model is a 1-D model consisting of the American River from Nimbus Dam (Lake Natoma) to the Sacramento River, and the NEMDC from Arcade Creek to the Sacramento River. It was adapted by MBK from the Sacramento River Watershed HEC-RAS model developed for the DWR Central Valley Floodplain Evaluation and Delineation (CVFED) project (Wood Rodgers, 2015). A schematic of the LAR model is provided in Figure 2. The LAR model was developed and executed with version 6.4.1 of HEC-RAS.

Figure 2. Lower American River HEC-RAS Model Schematic
The LAR model was calibrated using the January 1997 flood event, which had a peak American River flow of about 117,000 cfs. On February 10, 2017, when the flow in the lower American River was about 85,000 cfs, cbec Eco-engineering surveyed the water surface elevation at several locations. A simulation of the February 10, 2017, conditions was made to verify the model calibration. The results of the calibration and verification simulations are provided in Appendix A.

The LAR model was used to compute the ULDC WSE’s for the American River north levee.

4.2. North Area Streams (NAS) Model
The NAS model is a combined 1-D and 2-D model consisting of the stream reaches summarized in Table

4. The model was developed by MBK from an existing 1-D model, which was modified to use 2-D flow areas for reaches with small low flow channels and wide floodways, such as Dry Creek, Robla Creek and Magpie Creek. The 1-D elements are adapted from the CVFED modeling. A schematic of the model is provided in Figure 3. The downstream boundary of the model is the NEMDC at the American River north levee. WSE’s computed by the LAR model were used to define the downstream boundary condition of the NAS model The NAS model was developed and executed with version 6.4.1 of HEC-RAS.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 7 Table 4. Streams Within the Model Study Area
Stream Upstream Boundary Downstream Boundary Model
Element
Length
(miles)
Dry Creek Below Q Street NEMDC 2-D 3.5
Robla Creek Above 16th Street NEMDC 2-D 3.3
Magpie Creek Patrol Road Robla Creek 2-D 1.8
Don Julio Creek Patrol Road Magpie Creek 2-D 1.3
Arcade Creek Auburn Blvd. NEMDC 1-D 6.6
NEMDC D-15 Pump Station American R. north levee 1-D 4.3 Figure 3. North Area Stream HEC-RAS Model Schematic
A terrain model is required for 2-D modeling, as it is used to establish the geometric and hydraulic properties within 2-D flow areas. The primary terrain used for the NAS model was developed by USACE for use in their hydraulic analysis of the Magpie Creek project (USACE, 2021). The USACE terrain did not provide coverage of the entire NAS model study area, as shown in Figure 4. Terrain developed for the CVFED program (Wood Rodgers, 2014) was used to extend coverage to the entire NAS model study area, SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 8 as shown in Figure 5. The vertical and horizontal accuracy and resolution of the USACE terrain is not provided in the referenced documentation. The CVFED terrain has a vertical accuracy of 0.6 feet, a horizontal accuracy of 3.5 feet, and an average point spacing of 3.28 feet.

Figure 4. USACE Terrain Coverage (elevations are Figure 5. Final Terrain Coverage (elevations are in in feet NAVD88) feet NAVD88)
Manning’s n roughness coefficient values within the 2-D flow areas were defined using land classification mapping from the National Land Cover Database, as shown in Figure 6. Manning’s n-values were initially assigned for the various land classifications based on recommendations in the HEC-RAS 2D User’s Manual (USACE, 2023b), and refined as necessary through the calibration process. The land classifications and final associated n-values are listed in Table 5.

Table 5. Land Classifications and Assigned Manning’s n-values Land Classification Manning’s
n-value Land Classification Manning’s n-value
Barren Land Rock-Sand-Clay 0.035 Emergent Herbaceous Wetlands 0.06 Cultivated Crops 0.038 Evergreen Forest 0.08
Deciduous Forest 0.08 Grassland-Herbaceous 0.035
Developed, High Intensity 0.10 Open Water 0.03
Developed, Low Intensity 0.05 Pasture-Hay 0.042
Developed, Medium Intensity 0.07 Shrub-Scrub 0.08
Developed, Open Space 0.04 Woody Wetlands 0.07
The model was calibrated to the high flow event that occurred during the end of December 2005 and the beginning of January 2006 (the “2006 flood”). Calibration results are provided and summarized in Appendix B.

The NAS model was used to compute the ULDC WSE’s for the NEMDC east levee and the Arcade Creek south levee.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 9 Figure 6. Land Classification Map

4.3. Sacramento River System Models
The Sacramento River System models include the Sacramento River from Colusa at the upstream end to Collinsville at the downstream end, at the confluence of the Sacramento River and San Joaquin River in the eastern Sacramento-San Joaquin Delta. These models were used to compute the WSE at the mouth of the American River for use as downstream boundary conditions for the LAR model, accounting for the effects of sea level rise, as required by the ULDC, and the Federally authorized and under construction Sacramento Weir Widening project. The original intent had been to use the 2019 version, which had been used by MBK for a hydraulic impact analysis for the Sacramento Weir Widening Project (MBK Engineers, 2019), for the analysis. However, the 2019 analysis did not include simulations of the CVHS 1995 pattern flood events necessary for the Arcade Creek, Robla-Magpie Creeks, and Dry Creek flood centerings (see Table 3). Attempts were made to simulate the 1995 pattern flood events with the 2019 model, but these proved to be problematic. An earlier analysis was found that was made with the 2016 version of the SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 10 model and included simulations of the CVHS 1995 pattern flood events. Due to time constraints, it was decided to use the 2016 version of the model to compute the 1995 pattern WSE’s at the mouth of the American River for use as boundary conditions for the LAR model.

The 2019 version used HEC-RAS 5.0.7, and the 2016 model used HEC-RAS 5.0.1.

5. Urban Levee Design Criteria (ULDC)
Section 7.1 of the ULDC allows for two options for the determination of the DWSE. The first option is the Federal Emergency Management Agency (FEMA) Approach, in which the DWSE is computed deterministically with a hydraulic model. The second option is the U.S. Army Corps of Engineers Approach, which incorporates uncertainty into the determination of the DWSE. The approach selected for this analysis was the FEMA Approach, due to its application and results being more straightforward and economical.

The ULDC defines the DWSE as the “200-year stage or water level used to design a levee or floodwall”.

Section 7.1.1 of the ULDC specifies that the hydraulic modeling used to determine the DWSE must consider the following:
• Upstream, downstream, and nearby levees and floodwalls protecting urban areas are assumed to be raised to the median 200-year water surface elevation plus 3 feet and not allowed to breach, even if overtopped. Overtopping flows are assumed to leave the channel and remain in the 200- year floodplain.
• All project levees and floodwalls are to be modeled to incorporate a minimum crown elevation equal to the authorized (usually the 1955/1957) USACE design profiles – this affects nonurbanized areas for the most part – all such levees and floodwalls are to be allowed to overtop, act as weirs, and not breach for floods up to and including the median 500-year flood.

Overtopping flows are assumed to leave the channel and remain in the 200-year floodplain. • Non-project levees and floodwalls in non-urbanized areas in the region, to the extent they may affect the DWSE, are to be modeled at their existing or authorized height, whichever is higher, and to act as weirs without breaching if overtopped.
• Debris loading on bridges must be considered. Bridges with less than 3 feet of clearance above the DWSE may experience extraordinary debris loading that must be evaluated in addition to typical pier/bent debris loading. The evaluation should include historic and potential debris transport in the stream, an analysis of loading on the bridge, and analysis of backwater impacts on the DWSE in the vicinity of the bridge.

Section 7.1.3 of the ULDC requires adjustments to the DWSE for the effects of superelevation, when applicable. Superelevation is a tilting of the water surface, which may occur as water flows through a bend in the channel. Computational methods for determining superelevation adjustments are in the USACE Engineering Manual 1110-2-1601.

Section 7.1.3 of the ULDC also states that the “…the civil engineer should consider increasing the DWSE to account for the potential increases in water surface associated with climate change, updated hydrology, updated hydraulic models, and sea level rise”. This statement implies that adjustment for sea level rise is SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 11 optional; however, Section 7.19 of the ULDC states, “the effects of sea level rise are to be estimated and addressed for the duration during which a Finding that the urban level of flood protection exists may be valid”. Based on the second statement, sea level rise adjustment appears to be mandatory.

Additionally, Section 7.1.3 of the ULDC states:
“[T]he civil engineer also needs to address two other situations: (1) whether upstream levee or floodwall breaches could produce overland flows that would reach the area protected by the levee system or increase the water surface elevation along the levee system, and (2) whether flooding in a nearby leveed area could fill that area and breach a nearby levee or floodwall, returning flow to the stream and increasing the DWSE for a portion of the levee system".

Neither of these conditions are applicable to the Study Area, and therefore were not evaluated.

The following sections address the requirements in the ULDC and discuss the application of each requirement for the American River North levee system.

5.1 Levees
As per the ULDC, all urban levees were assumed to have a minimum top elevation of the median 200-year water surface elevation plus 3 feet. All non-urban State-Federal Project levees were assumed to have a minimum crown elevation equal to the authorized USACE design profiles.

5.2 Debris Loading
The ULDC specifies that debris loading on bridges must be considered, and that “bridges with less than 3 feet of clearance above the DWSE may experience extraordinary debris loading that must be evaluated in addition to typical pier/bent debris loading”.

Bridge pier debris are applied in accordance with guidelines provided in a July 2014 letter, sent by USACE to the California Central Valley Flood Protection Board in order to clarify the level of screening and analysis that should be included on encroachment permit applications that are sent to the USACE for review. A copy of the letter is provided in Appendix C. Included in the letter was guidance for modeling debris build-up. Based on this guidance, under the ULDC “typical” debris loading condition, the hydraulic analysis included floating debris with a width equal to double the pier width, and a depth of 2 feet below the water surface. Under the ULDC “extraordinary” debris loading condition, floating debris with a depth of 2 feet below the water surface were modeled for the full width with the “extraordinary” condition.

Debris were not applied to bridges in the model upstream of the levee reaches, as debris on these bridges would have no effect on the water surface elevation in the levee reaches.

A summary of the bridge pier debris conditions included in the hydraulic analysis is provided in Table 6.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 12 Table 6. Bridge Pier Debris Loading
River River
Station1 Bridge Debris Loading Condition2
200-yr 500-yr
Dry Creek West Branch 1,340 ft Rio Linda Blvd. E E
Dry Creek East Branch 3,910 ft SNRR Bike Trail t t
640 ft Rio Linda Blvd. E E
Dry Creek (lower) 6,120 ft private bridge E E
110 ft UPRR (near mouth) E E
Robla Creek 9,680 ft SNRR Bike Trail E E
8,290 ft Rio Linda Blvd. E E
90 ft UPRR (near mouth) E E
Magpie Creek 6,120 ft Raley Blvd. E E
4,010 ft Vinci Ave. E E
1,130 ft Dry Creek Rd. E E
Arcade Creek 1.344 mi Rio Linda Blvd. E E

1.26 mi SNRR Bike Trail E E

0.722 mi Norwood Avenue E E

0.045 mi UPRR (near mouth) E E
NEMDC 6.139 mi Main Avenue t t

5.168 mi Interstate 80 t t

4.347 mi Silver Eagle Road t t

3.03 mi West El Camino Avenue mix E

2.653 mi Arden-Garden Connector t t
American River 13.46 mi Bike Trail bridge t E

9.31 mi Watt Ave t E

7.748 mi Howe Ave t E

7.065 mi Guy West t E

6.588 mi H St t E

3.989 mi Cap City Fwy t t

3.715 mi RR t E

2.333 mi RR t E

2.235 mi Bike Trail t E

2.068 mi CA-160 E t mix

2.046 mi CA-160 W t mix

0.355 mi I-5 t mix

0.242 mi Jibboom St mix E
1 River station in miles for 1-D reaches and in feet for 2-D flow areas. 2 t = typical; E = extraordinary; mix = combination of t and E.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 13

5.3 Superelevation
Superelevation is a tilting of the water surface that occurs on the outside of a river bend. The ULDC notes that, “on the outside of a bend, the superelevation needs to be added to the DWSE”. The superelevation adjustment, per USACE Engineer Manual 1110-2-1416, River Hydraulics, is specific to 1-D hydraulic modeling. There are three locations in the ARN levee system where the superelevation adjustment applies (see Figure 7):
• American River, River Mile (RM) 5.7
• American River, RM 3.6
• NEMDC, RM 2.6
As recommended in the ULDC, computational methods in USACE Engineering Manual 1110-2-1601 were used to compute superelevation. Superelevation is computed with the following equation:
y = CV2
W/gr
where
y = superelevation (feet)
C = coefficient = 0.5 (tranquil, or subcritical, flow)
V = mean channel velocity (feet/second)
W = channel width at elevation of center-line water surface (feet) g = acceleration of gravity (32.2 feet/second2)
r = radius of channel center-line curvature
Figure 7. Superelevation Evaluation Locations
The computed superelevation and corresponding parameters are summarized in Table 7.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 14 Table 7. Superelevation
Location
r
(feet)
1/200 AEP 1/500 AEP
V
(feet/
second)
W
(feet)
Superelevation
(feet)
V
(feet/
second)
W
(feet)
Superelevation
(feet)
American R, RM 5.6 1,300 3.7 1,920 0.3 4.2 2,030 0.4
American R, RM 3.6 2,900 4.4 2,290 0.2 4.5 2,330 0.3
NEMDC, RM 2.6 1,900 2.4 470 0.0 3.4 500 0.0
The American River RM 5.6 superelevation adjustment was applied to the computed water surface elevations at cross sections 5.682 and 5.502. The American River RM 3.6 superelevation adjustment was applied to the computed water surface elevations at cross sections 3.735, 3.688 and 3.600. No superelevation adjustment was needed at the NEMDC RM 2.6 location.

5.4 Climate Change
The effects of climate change on extreme precipitation events in the Central Valley are being studied, but there is no indication of what the outcome of that work will be. Therefore, the hydrology used in this analysis has not been adjusted for the effects of climate change.

5.5 Updated Hydrology
This analysis makes use of the most recent accepted hydrologic data for the Study Area, which was developed as part of the Central Valley Hydrology Study, as noted in Section 4 of this report.

5.6 Updated Hydraulic Model
The hydraulic model used for this analysis was developed from the most current available data. Due to the calibration process, an updated hydraulic model would not be expected to have a substantial effect on the computed results unless significant physical changes have occurred in the modeled system. Since no significant physical changes have occurred since the data used for the model development was collected, no adjustment for updated hydraulic model has been included.

5.7 Sea Level Rise
The ULDC notes that, “the effects of sea level rise are to be estimated and addressed for the duration during which a Finding that the urban level of flood protection exists may be valid”. The duration of finding proposed for the subject project is 20 years.

The analysis assumed a sea level rise of 3.68 feet at San Francisco. This is the 50-year sea level rise projection determined by DWR for the 2022 update of the Central Valley Flood Protection Plan (CVFPP) (DWR, 2022). Being that the duration of the Urban Level of Protection finding is 20 years, the use of a 50- year projection is a conservative assumption. The effects of this sea level rise were applied at the downstream boundaries of the Sacramento River systemwide hydraulic model simulations, which were used to determine the downstream boundary conditions for the LAR model.

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American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 15

6. Computed ULDC Hydraulic Parameters
The following sections present the computed ULDC hydraulic parameters that were described in Section 1 of this technical memorandum:
• Design Water Surface Elevation (DWSE)
• Minimum Top of Levee (MTOL)
• Hydraulic Top of Levee (HTOL)
• Seismic Vulnerability Restoration Profile

6.1 Design Water Surface Elevation (DWSE)
The ULDC defines the DWSE as “[the] median 200-year water surface elevation”, with adjustments for the following factors:
• Bridge pier debris loading
• Superelevation
• Sea level rise
Debris loading and sea level rise are accounted for in the hydraulic model simulations, as described in Sections 5.2 and 5.7. As noted in Section 5.3, the superelevation adjustment was applied at two locations on the American River north levee.

Profile plots of the computed DWSE for each of the levee segments in the ARN levee system are provided in Figures 8, 9 and 10. The levee crest profiles are included on the profile plots. Tabulations of the DWSE profiles are provided in Appendix D.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 16 Figure 8. ULDC DWSE Profile, American River North Levee Figure 9. ULDC DWSE Profile, Arcade Creek South Levee
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 17 Figure 10. ULDC DWSE Profile, NEMDC East Levee

6.2 Minimum Top of Levee (MTOL)
The ULDC defines the MTOL as the higher of the DWSE plus 3 feet, or the DWSE plus the computed wind setup and wave runup. Wind setup and wave runup for the ARN levee system has been computed by Mead & Hunt (Mead & Hunt, 2024). The maximum computed wind setup and wave runup is 3.0 feet.

Since this does not exceed 3 feet, the MTOL for the ARN levee system levees is the DWSE plus 3 feet.

Profile plots of the MTOL for each of the levee segments in the ARN levee system are provided in Figures 11, 12 and 13. Tabulation of the MTOL profiles are provided in Appendix D.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 18 Figure 11. ULDC MTOL Profile, American River North Levee Figure 12. ULDC MTOL Profile, Arcade Creek South Levee
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 19 Figure 13. ULDC MTOL Profile, NEMDC East Levee

6.3. Hydraulic Top of Levee (HTOL)
The ULDC defines the HTOL as the lower of the DWSE plus 3 feet, or the median 500-year WSE. Profile plots of the HTOL for each of the levee segments in the ARN levee system are provided in Figures 14, 15 and 16. For reference, the DWSE plus 3 feet and 500-year WSE profiles are also shown. Tabulations of the HTOL profiles are provided in Appendix D.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 20 Figure 14. ULDC HTOL Profile, American River North Levee Figure 15. ULDC HTOL Profile, Arcade Creek South Levee
SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 21 Figure 16. ULDC HTOL Profile, NEMDC East Levee

6.4 Seismic Vulnerability Restoration Profile (SVRP)
The ULDC specifies that if there is the potential for levee damage due to a seismic event, a plan needs to be in place to “restore grade and dimensions for at least 10-year WSE plus 3 feet of freeboard or higher for wind setup and wave runup within 8 weeks”. An evaluation of seismic performance of the American River North levee system by Kleinfelder (Kleinfelder, 2024) determined that there were locations on the American River north levee that have high seismic vulnerability, as defined in the DWR Urban Levee Evaluation (ULE) program, and that the Arcade Creek south levee and NEMDC east levee have low seismic vulnerability. Therefore, the seismic vulnerability restoration profile has been developed for the American River north levee, but is unnecessary for the Arcade Creek south levee and NEMDC east levee. A profile plot of the seismic vulnerability restoration profile for the American River north levee is provided in Figure17. A tabulation of the seismic vulnerability restoration profile is included in Appendix D.

SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 22 Figure 17. Seismic Vulnerability Restoration Profile, American River North Levee SAFCA July 1, 2024
American River North Levee System - Determination of the UDLC DWSE, MTOL, and HTOL Page 23 References
County of Sacramento. (2007). D-15 NEMDC Drainage Pump Station Summary of Operations and Procedures Manual. May 2007.

DWR. (2012). Urban Levee Design Criteria. May 2012.

DWR. (2022). 2022 CVFPP Update - Technical Analyses Summary Report. November 2022.

Kleinfelder. (2024). Seismic Performance Summary Report, North Area Streams Levee Areas. February 12, 2024.

MBK Engineers. (2019). Technical Memorandum - Sacramento Weir Widening Project, Initial Hydraulic Impact Analysis. October 31, 2019.

Mead & Hunt. (2024). Wind-Wave Analysis for American River North and Robla-Arcade Levee Systems.

January 16, 2024.

USACE. (2013). Central Valley Hydrology Study: Natomas-area Stream Group - Pleasant Grove Creek, Dry Creek, and Arcade Creek Watersheds Hydrologic Analysis. March 26, 2013.

USACE. (2015). Central Valley Hydrology Study. November 29, 2015.

USACE. (2019). Memorandum for Record, Subject: CVHS Hydrograph Package for HEC-RAS Model Inputs. February 20, 2019.

USACE. (2020). Hydrology Technical Memorandum for Developing WRDA 2016 Water Surface Profiles.

April 10, 2020.

USACE. (2021). Hydraulic Model Summary Magpie Creek Canal For American River Common Features Project. USACE - Vicksburg District. April 2021.

USACE. (2023a). HEC-RAS User's Manual. Retrieved from
https://www.hec.usace.army.mil/confluence/rasdocs/rasum/6.4 USACE. (2023b). HEC-RAS 2D User's Manual. Retrieved from https://www.hec.usace.army.mil/confluence/rasdocs/r2dum/latest Wood Rodgers. (2014). Central Valley Floodplain Evaluation and Delineation, Lower Sacramento River Technical Memorandum. January 17, 2014.

Wood Rodgers. (2015). Refine/Calibrate Combined Sacramento River and San Joaquin River Systems, Sacramento River System Study Area Report. May 29, 2015.

APPENDIX A
Lower American River
Hydraulic Model Calibration
Simulation Event Peak American River flow
Calibration January 1997 flow 117,000 cfs
Verification February 10, 2017 ~85,000 cfs
Figure A-1. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River river miles 10 to 23 (Mayhew Drain to Nimbus Dam) Figure A-2. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River river miles 0 to 11 (Sacramento River to Mayhew Drain) Figure A-3. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevation, American River river miles 10 to 23 (Mayhew Drain to Nimbus Dam)
Figure A-4. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevation, American River river miles 0 to 11 (Sacramento River to Mayhew Drain)

Figure A-1. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River, river miles 10 to 23 (Mayhew Drain to Nimbus Dam) Figure A-2. Calibration, January 1997, Maximum Water Surface Elevation Profile with Surveyed High Water Marks, American River, river miles 0 to 11 (Sacramento River to Mayhew Drain)

Figure A-3. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevations, American River, river miles 10 to 23 (Mayhew Drain to Nimbus Dam) Figure A-4. Verification, February 10, 2017, Maximum Water Surface Elevation Profile with Surveyed Water Surface Elevations, American River, river miles 0 to 11 (Sacramento River to Mayhew Drain)

APPENDIX B
North Area Streams
Hydraulic Model Calibration
B-1
Calibration flood event: December 2005-January 2006
The stream gages listed in Table B-1 provided the available observed data used for calibration of the Dry Creek and Robla Creek watershed area. All the gages are part of the Sacramento County ALERT system (https://www.sacflood.org/). The gage data was provided by Sacramento County. The gage locations are shown in Figure B-1.

Table B-1. Stream Gages with Observed Data Available for Calibration Gage Agency Sensor ID
Dry Creek West Branch at SNRR Bike Trail Sacramento County ALERT 2230 Dry Creek West Branch at Elkhorn Blvd. Sacramento County ALERT 1661 Dry Creek Bypass at Elkhorn Blvd. Sacramento County ALERT 1662 Dry Creek East Branch at Elkhorn Blvd. Sacramento County ALERT 2782 Robla Creek at SNRR Bike Trail Sacramento County ALERT 2753 D15/NEMDC Downstream Sacramento County ALERT 2772
Figure B-1. Stream Gage Location Map
A comparison of the observed and computed peak stages at the gage locations is provided in Table B-2.

Profile plots of the computed maximum water surface elevations with available observed gage peaks are B-2
provided in Figures B-2 through B-6.

Table B-2. Calibration Results, Comparison of Observed and Computed Peak Stages Gage Maximum Stage (feet NAVD88) Difference
Observed Computed (feet)
Dry Creek West Branch at SNRR Bike Trail 47.62 48.06 +0.44 Dry Creek West Branch at Elkhorn Blvd. 46.06 46.17 +0.11 Dry Creek Bypass at Elkhorn Blvd. 46.95 46.58 -0.37
Dry Creek East Branch at Elkhorn Blvd. 46.88 49.33 +2.45 a Robla Creek at SNRR Bike Trail 40.59 40.78 +0.19
D15/NEMDC Downstream 36.44 36.69 +0.25
a The Sacramento County ALERT website for this gage notes that “when the east branch reaches 49.9’ +/- the stage at the west branch is approximately 46.5’ +/-“. The computed peak stage difference for these locations of 3.2’ is similar to the reported difference of 3.6’. Therefore, it can be concluded that the reported peak stage of 46.88’ at the Dry Creek East Branch at Elkhorn Blvd gage is suspect.

Figure B-2. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek West Branch B-3
Figure B-3. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek East Branch Figure B-4. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek (lower) B-4
Figure B-5. Calibration Analysis Maximum Water Surface Elevation Profile, Dry Creek Bypass Channel Figure B-6. Calibration Analysis Maximum Water Surface Elevation Profile, Robla Creek

Appendix C
USACE Letter with Debris Loading Guidance
C-1
C-2
C-3
C-4
C-5
C-6
C-7
C-8
C-9

APPENDIX D

Tabulation of ULDC Hydraulic Parameter Profiles for the American River North Levee System Profile Acronyms:

DWSE design water surface elevation
MTOL minimum top of levee
HTOL hydraulic top of levee
SVRP seismic vulnerability restoration profile
D-1
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3000+00 35.64 38.64 38.64 34.46 3052+00 37.09 40.09 40.09 35.52 3001+00 35.61 38.61 38.61 34.47 3053+00 37.10 40.10 40.10 35.53 3002+00 35.58 38.58 38.58 34.48 3054+00 37.11 40.11 40.11 35.53 3003+00 35.55 38.55 38.55 34.48 3055+00 37.12 40.12 40.12 35.54 3004+00 35.52 38.52 38.52 34.49 3056+00 37.14 40.14 40.14 35.55 3005+00 35.50 38.50 38.50 34.50 3057+00 37.15 40.15 40.15 35.56 3006+00 35.47 38.47 38.47 34.51 3058+00 37.16 40.16 40.16 35.57 3007+00 35.48 38.48 38.48 34.51 3059+00 37.17 40.17 40.17 35.58 3008+00 35.49 38.49 38.49 34.52 3060+00 37.18 40.18 40.18 35.59 3009+00 35.51 38.51 38.51 34.53 3061+00 37.20 40.20 40.20 35.60 3010+00 35.52 38.52 38.52 34.54 3062+00 37.21 40.21 40.21 35.61 3011+00 35.53 38.53 38.53 34.55 3063+00 37.23 40.23 40.23 35.63 3012+00 35.55 38.55 38.55 34.56 3064+00 37.24 40.24 40.24 35.64 3013+00 35.56 38.56 38.56 34.56 3065+00 37.26 40.26 40.26 35.65 3014+00 35.55 38.55 38.55 34.56 3066+00 37.27 40.27 40.27 35.66 3015+00 35.55 38.55 38.55 34.55 3067+00 37.29 40.29 40.29 35.67 3016+00 35.91 38.91 38.91 34.77 3068+00 37.30 40.30 40.30 35.68 3017+00 35.99 38.99 38.99 34.82 3069+00 37.32 40.32 40.32 35.69 3018+00 36.07 39.07 39.07 34.89 3070+00 37.34 40.34 40.34 35.70 3019+00 36.15 39.15 39.15 34.94 3071+00 37.37 40.37 40.37 35.71 3020+00 36.29 39.29 39.29 35.02 3072+00 37.40 40.40 40.40 35.71 3021+00 36.28 39.28 39.28 35.00 3073+00 37.44 40.44 40.44 35.72 3022+00 36.30 39.30 39.30 35.00 3074+00 37.47 40.47 40.47 35.72 3023+00 36.32 39.32 39.32 35.01 3075+00 37.50 40.50 40.50 35.72 3024+00 36.33 39.33 39.33 35.02 3076+00 37.53 40.53 40.53 35.73 3025+00 36.35 39.35 39.35 35.03 3077+00 37.57 40.57 40.57 35.74 3026+00 36.36 39.36 39.36 35.04 3078+00 37.63 40.63 40.63 35.79 3027+00 36.38 39.38 39.38 35.04 3079+00 37.69 40.69 40.69 35.83 3028+00 36.40 39.40 39.40 35.05 3080+00 37.75 40.75 40.75 35.87 3029+00 36.41 39.41 39.41 35.06 3081+00 37.81 40.81 40.81 35.91 3030+00 36.43 39.43 39.43 35.07 3082+00 37.87 40.87 40.87 35.95 3031+00 36.44 39.44 39.44 35.08 3083+00 37.92 40.92 40.92 35.99 3032+00 36.46 39.46 39.46 35.08 3084+00 37.94 40.94 40.94 36.02 3033+00 36.48 39.48 39.48 35.09 3085+00 37.87 40.87 40.87 35.97 3034+00 36.49 39.49 39.49 35.10 3086+00 38.06 41.06 41.06 36.12 3035+00 36.54 39.54 39.54 35.13 3087+00 38.06 41.06 41.06 36.13 3036+00 36.58 39.58 39.58 35.16 3088+00 38.05 41.05 41.05 36.13 3037+00 36.63 39.63 39.63 35.18 3089+00 38.05 41.05 41.05 36.13 3038+00 36.67 39.67 39.67 35.21 3090+00 38.04 41.04 41.04 36.14 3039+00 36.72 39.72 39.72 35.25 3091+00 38.03 41.03 41.03 36.14 3040+00 36.77 39.77 39.77 35.28 3092+00 38.03 41.03 41.03 36.14 3041+00 36.83 39.83 39.83 35.32 3093+00 38.02 41.02 41.02 36.14 3042+00 36.88 39.88 39.88 35.36 3094+00 38.01 41.01 41.01 36.15 3043+00 36.92 39.92 39.92 35.39 3095+00 38.01 41.01 41.01 36.15 3044+00 36.95 39.95 39.95 35.41 3096+00 38.00 41.00 41.00 36.15 3045+00 36.98 39.98 39.98 35.43 3097+00 37.99 40.99 40.99 36.16 3046+00 37.01 40.01 40.01 35.45 3098+00 37.99 40.99 40.99 36.16 3047+00 37.03 40.03 40.03 35.47 3099+00 37.98 40.98 40.98 36.16 3048+00 37.04 40.04 40.04 35.48 3100+00 37.99 40.99 40.99 36.17 3049+00 37.06 40.06 40.06 35.49 3101+00 38.02 41.02 41.02 36.20 3050+00 37.07 40.07 40.07 35.50 3102+00 38.14 41.14 41.14 36.27 3051+00 37.08 40.08 40.08 35.51 3103+00 38.09 41.09 41.09 36.22 D-2
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3104+00 38.12 41.12 41.12 36.23 3156+00 40.06 43.06 43.06 37.93 3105+00 38.15 41.15 41.15 36.26 3157+00 40.11 43.11 43.11 37.99 3106+00 38.19 41.19 41.19 36.29 3158+00 40.13 43.13 43.13 38.00 3107+00 38.22 41.22 41.22 36.32 3159+00 40.15 43.15 43.15 38.01 3108+00 38.25 41.25 41.25 36.34 3160+00 40.16 43.16 43.16 38.02 3109+00 38.28 41.28 41.28 36.36 3161+00 40.18 43.18 43.18 38.03 3110+00 38.31 41.31 41.31 36.38 3162+00 40.19 43.19 43.19 38.04 3111+00 38.34 41.34 41.34 36.40 3163+00 40.21 43.21 43.21 38.05 3112+00 38.37 41.37 41.37 36.42 3164+00 40.22 43.22 43.22 38.06 3113+00 38.41 41.41 41.41 36.44 3165+00 40.24 43.24 43.24 38.06 3114+00 38.43 41.43 41.43 36.45 3166+00 40.25 43.25 43.25 38.07 3115+00 38.43 41.43 41.43 36.45 3167+00 40.27 43.27 43.27 38.08 3116+00 38.43 41.43 41.43 36.44 3168+00 40.28 43.28 43.28 38.09 3117+00 38.43 41.43 41.43 36.44 3169+00 40.32 43.32 43.32 38.11 3118+00 38.44 41.44 41.44 36.43 3170+00 40.39 43.39 43.39 38.15 3119+00 38.44 41.44 41.44 36.43 3171+00 40.45 43.45 43.45 38.18 3120+00 38.44 41.44 41.44 36.43 3172+00 40.51 43.51 43.51 38.21 3121+00 38.44 41.44 41.44 36.42 3173+00 40.58 43.58 43.58 38.25 3122+00 38.44 41.44 41.44 36.42 3174+00 40.64 43.64 43.64 38.28 3123+00 38.45 41.45 41.45 36.42 3175+00 40.71 43.71 43.71 38.32 3124+00 38.50 41.50 41.50 36.46 3176+00 40.77 43.77 43.77 38.35 3125+00 38.57 41.57 41.57 36.53 3177+00 40.83 43.83 43.83 38.39 3126+00 38.64 41.64 41.64 36.59 3178+00 40.90 43.90 43.90 38.42 3127+00 38.71 41.71 41.71 36.66 3179+00 40.96 43.96 43.96 38.45 3128+00 38.78 41.78 41.78 36.73 3180+00 41.02 44.02 44.02 38.49 3129+00 38.85 41.85 41.85 36.79 3181+00 41.05 44.05 44.05 38.51 3130+00 38.92 41.92 41.92 36.86 3182+00 41.07 44.07 44.07 38.53 3131+00 38.99 41.99 41.99 36.93 3183+00 41.10 44.10 44.10 38.55 3132+00 39.06 42.06 42.06 36.99 3184+00 41.12 44.12 44.12 38.58 3133+00 39.10 42.10 42.10 37.03 3185+00 41.15 44.15 44.15 38.60 3134+00 39.14 42.14 42.14 37.05 3186+00 41.17 44.17 44.17 38.62 3135+00 39.17 42.17 42.17 37.07 3187+00 41.19 44.19 44.19 38.65 3136+00 39.20 42.20 42.20 37.10 3188+00 41.22 44.22 44.22 38.67 3137+00 39.23 42.23 42.23 37.12 3189+00 41.24 44.24 44.24 38.69 3138+00 39.27 42.27 42.27 37.15 3190+00 41.27 44.27 44.27 38.71 3139+00 39.30 42.30 42.30 37.18 3191+00 41.29 44.29 44.29 38.74 3140+00 39.34 42.34 42.34 37.21 3192+00 41.31 44.31 44.31 38.76 3141+00 39.39 42.39 42.39 37.25 3193+00 41.30 44.30 44.30 38.78 3142+00 39.43 42.43 42.43 37.28 3194+00 41.30 44.30 44.30 38.81 3143+00 39.47 42.47 42.47 37.31 3195+00 41.29 44.29 44.29 38.83 3144+00 39.51 42.51 42.51 37.35 3196+00 41.28 44.28 44.28 38.85 3145+00 39.55 42.55 42.55 37.38 3197+00 41.28 44.28 44.28 38.88 3146+00 39.59 42.59 42.59 37.41 3198+00 41.27 44.27 44.27 38.90 3147+00 39.63 42.63 42.63 37.45 3199+00 41.27 44.27 44.27 38.92 3148+00 39.67 42.67 42.67 37.49 3200+00 41.26 44.26 44.26 38.95 3149+00 39.72 42.72 42.72 37.55 3201+00 41.25 44.25 44.25 38.97 3150+00 39.77 42.77 42.77 37.60 3202+00 41.25 44.25 44.25 38.99 3151+00 39.82 42.82 42.82 37.66 3203+00 41.22 44.22 44.22 38.97 3152+00 39.87 42.87 42.87 37.71 3204+00 41.19 44.19 44.19 38.95 3153+00 39.92 42.92 42.92 37.77 3205+00 41.15 44.15 44.15 38.93 3154+00 39.96 42.96 42.96 37.82 3206+00 41.12 44.12 44.12 38.91 3155+00 40.01 43.01 43.01 37.88 3207+00 41.09 44.09 44.09 38.89 D-3
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3208+00 41.06 44.06 44.06 38.87 3260+00 43.77 46.77 46.77 41.24 3209+00 41.03 44.03 44.03 38.85 3261+00 43.83 46.83 46.83 41.28 3210+00 41.00 44.00 44.00 38.83 3262+00 43.89 46.89 46.89 41.31 3211+00 40.97 43.97 43.97 38.81 3263+00 43.95 46.95 46.95 41.35 3212+00 40.94 43.94 43.94 38.79 3264+00 44.01 47.01 47.01 41.39 3213+00 40.92 43.92 43.92 38.78 3265+00 44.32 47.32 47.32 41.62 3214+00 41.03 44.03 44.03 38.89 3266+00 44.41 47.41 47.41 41.68 3215+00 41.15 44.15 44.15 38.99 3267+00 44.50 47.50 47.50 41.74 3216+00 41.26 44.26 44.26 39.10 3268+00 44.59 47.59 47.59 41.80 3217+00 41.38 44.38 44.38 39.21 3269+00 44.67 47.67 47.67 41.86 3218+00 41.49 44.49 44.49 39.32 3270+00 44.76 47.76 47.76 41.92 3219+00 41.60 44.60 44.60 39.40 3271+00 44.85 47.85 47.85 41.98 3220+00 41.69 44.69 44.69 39.46 3272+00 44.96 47.96 47.96 42.07 3221+00 41.79 44.79 44.79 39.53 3273+00 45.10 48.10 48.10 42.18 3222+00 41.89 44.89 44.89 39.60 3274+00 45.23 48.23 48.23 42.29 3223+00 41.99 44.99 44.99 39.67 3275+00 45.13 48.13 48.13 42.21 3224+00 42.09 45.09 45.09 39.76 3276+00 45.34 48.34 48.34 42.36 3225+00 42.20 45.20 45.20 39.85 3277+00 45.61 48.61 48.61 42.58 3226+00 42.30 45.30 45.30 39.94 3278+00 45.68 48.68 48.68 42.64 3227+00 42.41 45.41 45.41 40.03 3279+00 45.75 48.75 48.75 42.69 3228+00 42.46 45.46 45.46 40.07 3280+00 45.81 48.81 48.81 42.74 3229+00 42.47 45.47 45.47 40.09 3281+00 45.83 48.83 48.83 42.76 3230+00 42.49 45.49 45.49 40.12 3282+00 45.85 48.85 48.85 42.77 3231+00 42.50 45.50 45.50 40.14 3283+00 45.87 48.87 48.87 42.79 3232+00 42.52 45.52 45.52 40.16 3284+00 45.89 48.89 48.89 42.80 3233+00 42.54 45.54 45.54 40.20 3285+00 45.91 48.91 48.91 42.82 3234+00 42.58 45.58 45.58 40.26 3286+00 45.93 48.93 48.93 42.83 3235+00 42.61 45.61 45.61 40.32 3287+00 45.95 48.95 48.95 42.85 3236+00 42.64 45.64 45.64 40.37 3288+00 45.99 48.99 48.99 42.88 3237+00 42.69 45.69 45.69 40.43 3289+00 46.06 49.06 49.06 42.93 3238+00 42.75 45.75 45.75 40.50 3290+00 46.13 49.13 49.13 42.99 3239+00 42.82 45.82 45.82 40.57 3291+00 46.20 49.20 49.20 43.04 3240+00 42.88 45.88 45.88 40.63 3292+00 46.27 49.27 49.27 43.09 3241+00 43.04 46.04 46.04 40.77 3293+00 46.34 49.34 49.34 43.15 3242+00 42.84 45.84 45.84 40.65 3294+00 46.32 49.32 49.32 43.13 3243+00 42.99 45.99 45.99 40.74 3295+00 46.31 49.31 49.31 43.12 3244+00 43.14 46.14 46.14 40.84 3296+00 46.36 49.36 49.36 43.17 3245+00 43.29 46.29 46.29 40.93 3297+00 46.40 49.40 49.40 43.22 3246+00 43.45 46.45 46.45 41.03 3298+00 46.45 49.45 49.45 43.27 3247+00 43.50 46.50 46.50 41.07 3299+00 46.49 49.49 49.49 43.32 3248+00 43.55 46.55 46.55 41.11 3300+00 46.56 49.56 49.56 43.38 3249+00 43.60 46.60 46.60 41.15 3301+00 46.65 49.65 49.65 43.44 3250+00 43.65 46.65 46.65 41.19 3302+00 46.74 49.74 49.74 43.51 3251+00 43.66 46.66 46.66 41.20 3303+00 46.82 49.82 49.82 43.57 3252+00 43.64 46.64 46.64 41.18 3304+00 46.91 49.91 49.91 43.63 3253+00 43.62 46.62 46.62 41.17 3305+00 46.95 49.95 49.95 43.67 3254+00 43.60 46.60 46.60 41.15 3306+00 46.98 49.98 49.98 43.70 3255+00 43.60 46.60 46.60 41.15 3307+00 47.01 50.01 50.01 43.73 3256+00 43.63 46.63 46.63 41.17 3308+00 47.04 50.04 50.04 43.76 3257+00 43.66 46.66 46.66 41.18 3309+00 47.08 50.08 50.08 43.79 3258+00 43.69 46.69 46.69 41.20 3310+00 47.11 50.11 50.11 43.82 3259+00 43.73 46.73 46.73 41.22 3311+00 47.15 50.15 50.15 43.85 D-4
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3312+00 47.19 50.19 50.19 43.88 3364+00 48.70 51.70 51.70 45.16 3313+00 47.23 50.23 50.23 43.92 3365+00 48.67 51.67 51.67 45.15 3314+00 47.27 50.27 50.27 43.95 3366+00 48.64 51.64 51.64 45.13 3315+00 47.31 50.31 50.31 43.98 3367+00 48.61 51.61 51.61 45.12 3316+00 47.32 50.32 50.32 43.99 3368+00 48.58 51.58 51.58 45.10 3317+00 47.33 50.33 50.33 43.99 3369+00 48.55 51.55 51.55 45.08 3318+00 47.33 50.33 50.33 44.00 3370+00 48.52 51.52 51.52 45.07 3319+00 47.34 50.34 50.34 44.01 3371+00 48.49 51.49 51.49 45.05 3320+00 47.35 50.35 50.35 44.01 3372+00 48.47 51.47 51.47 45.03 3321+00 47.34 50.34 50.34 44.01 3373+00 48.44 51.44 51.44 45.02 3322+00 47.33 50.33 50.33 44.00 3374+00 48.42 51.42 51.42 45.02 3323+00 47.32 50.32 50.32 44.00 3375+00 48.54 51.54 51.54 45.11 3324+00 47.31 50.31 50.31 43.99 3376+00 48.59 51.59 51.59 45.13 3325+00 47.30 50.30 50.30 43.99 3377+00 48.67 51.67 51.67 45.20 3326+00 47.30 50.30 50.30 43.98 3378+00 48.75 51.75 51.75 45.27 3327+00 47.32 50.32 50.32 44.00 3379+00 48.83 51.83 51.83 45.35 3328+00 47.33 50.33 50.33 44.01 3380+00 48.91 51.91 51.91 45.42 3329+00 47.35 50.35 50.35 44.03 3381+00 48.99 51.99 51.99 45.49 3330+00 47.36 50.36 50.36 44.04 3382+00 49.07 52.07 52.07 45.56 3331+00 47.36 50.36 50.36 44.04 3383+00 49.15 52.15 52.15 45.63 3332+00 47.36 50.36 50.36 44.05 3384+00 49.23 52.23 52.23 45.70 3333+00 47.37 50.37 50.37 44.05 3385+00 49.30 52.30 52.30 45.77 3334+00 47.39 50.39 50.39 44.07 3386+00 49.34 52.34 52.34 45.82 3335+00 47.42 50.42 50.42 44.10 3387+00 49.39 52.39 52.39 45.87 3336+00 47.45 50.45 50.45 44.13 3388+00 49.43 52.43 52.43 45.92 3337+00 47.49 50.49 50.49 44.16 3389+00 49.48 52.48 52.48 45.97 3338+00 47.52 50.52 50.52 44.19 3390+00 49.52 52.52 52.52 46.02 3339+00 47.50 50.50 50.50 44.17 3391+00 49.57 52.57 52.57 46.07 3340+00 47.47 50.47 50.47 44.15 3392+00 49.62 52.62 52.62 46.12 3341+00 47.45 50.45 50.45 44.14 3393+00 49.66 52.66 52.66 46.17 3342+00 47.42 50.42 50.42 44.12 3394+00 49.71 52.71 52.71 46.22 3343+00 47.41 50.41 50.41 44.11 3395+00 49.79 52.79 52.79 46.29 3344+00 47.47 50.47 50.47 44.16 3396+00 49.90 52.90 52.90 46.39 3345+00 47.53 50.53 50.53 44.21 3397+00 50.01 53.01 53.01 46.48 3346+00 47.58 50.58 50.58 44.26 3398+00 50.12 53.12 53.12 46.57 3347+00 47.64 50.64 50.64 44.31 3399+00 50.22 53.22 53.22 46.66 3348+00 47.70 50.70 50.70 44.36 3400+00 50.26 53.26 53.26 46.69 3349+00 47.76 50.76 50.76 44.41 3401+00 50.30 53.30 53.30 46.72 3350+00 47.81 50.81 50.81 44.46 3402+00 50.34 53.34 53.34 46.75 3351+00 47.86 50.86 50.86 44.50 3403+00 50.38 53.38 53.38 46.78 3352+00 47.92 50.92 50.92 44.55 3404+00 50.40 53.40 53.40 46.82 3353+00 47.97 50.97 50.97 44.59 3405+00 50.42 53.42 53.42 46.87 3354+00 48.04 51.04 51.04 44.65 3406+00 50.44 53.44 53.44 46.91 3355+00 48.11 51.11 51.11 44.70 3407+00 50.45 53.45 53.45 46.96 3356+00 48.18 51.18 51.18 44.75 3408+00 50.51 53.51 53.51 47.02 3357+00 48.25 51.25 51.25 44.81 3409+00 50.58 53.58 53.58 47.09 3358+00 48.32 51.32 51.32 44.86 3410+00 50.65 53.65 53.65 47.16 3359+00 48.39 51.39 51.39 44.92 3411+00 50.72 53.72 53.72 47.22 3360+00 48.46 51.46 51.46 44.97 3412+00 50.79 53.79 53.79 47.28 3361+00 48.53 51.53 51.53 45.02 3413+00 50.85 53.85 53.85 47.34 3362+00 48.59 51.59 51.59 45.08 3414+00 50.91 53.91 53.91 47.40 3363+00 48.66 51.66 51.66 45.13 3415+00 50.96 53.96 53.96 47.46 D-5
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3416+00 51.02 54.02 54.02 47.51 3468+00 53.04 56.04 56.04 49.16 3417+00 51.08 54.08 54.08 47.55 3469+00 53.03 56.03 56.03 49.15 3418+00 51.13 54.13 54.13 47.59 3470+00 53.02 56.02 56.02 49.15 3419+00 51.18 54.18 54.18 47.63 3471+00 53.01 56.01 56.01 49.15 3420+00 51.23 54.23 54.23 47.67 3472+00 53.00 56.00 56.00 49.14 3421+00 51.30 54.30 54.30 47.72 3473+00 52.99 55.99 55.99 49.14 3422+00 51.38 54.38 54.38 47.77 3474+00 52.99 55.99 55.99 49.14 3423+00 51.45 54.45 54.45 47.82 3475+00 52.99 55.99 55.99 49.14 3424+00 51.53 54.53 54.53 47.87 3476+00 52.98 55.98 55.98 49.14 3425+00 51.63 54.63 54.63 47.95 3477+00 52.98 55.98 55.98 49.14 3426+00 51.77 54.77 54.77 48.05 3478+00 52.98 55.98 55.98 49.14 3427+00 51.90 54.90 54.90 48.15 3479+00 52.98 55.98 55.98 49.15 3428+00 52.04 55.04 55.04 48.26 3480+00 52.98 55.98 55.98 49.15 3429+00 52.13 55.13 55.13 48.33 3481+00 52.97 55.97 55.97 49.15 3430+00 52.14 55.14 55.14 48.33 3482+00 52.97 55.97 55.97 49.15 3431+00 52.14 55.14 55.14 48.33 3483+00 52.97 55.97 55.97 49.15 3432+00 52.17 55.17 55.17 48.35 3484+00 52.98 55.98 55.98 49.16 3433+00 52.21 55.21 55.21 48.39 3485+00 52.99 55.99 55.99 49.17 3434+00 52.26 55.26 55.26 48.43 3486+00 53.01 56.01 56.01 49.18 3435+00 52.30 55.30 55.30 48.47 3487+00 53.02 56.02 56.02 49.20 3436+00 52.34 55.34 55.34 48.50 3488+00 53.03 56.03 56.03 49.21 3437+00 52.39 55.39 55.39 48.54 3489+00 53.04 56.04 56.04 49.22 3438+00 52.43 55.43 55.43 48.58 3490+00 53.06 56.06 56.06 49.23 3439+00 52.47 55.47 55.47 48.62 3491+00 53.07 56.07 56.07 49.24 3440+00 52.52 55.52 55.52 48.66 3492+00 53.08 56.08 56.08 49.26 3441+00 52.56 55.56 55.56 48.69 3493+00 53.10 56.10 56.10 49.27 3442+00 52.58 55.58 55.58 48.71 3494+00 53.12 56.12 56.12 49.27 3443+00 52.60 55.60 55.60 48.73 3495+00 53.14 56.14 56.14 49.28 3444+00 52.62 55.62 55.62 48.75 3496+00 53.17 56.17 56.17 49.29 3445+00 52.64 55.64 55.64 48.77 3497+00 53.19 56.19 56.19 49.29 3446+00 52.66 55.66 55.66 48.79 3498+00 53.21 56.21 56.21 49.30 3447+00 52.68 55.68 55.68 48.80 3499+00 53.24 56.24 56.24 49.31 3448+00 52.70 55.70 55.70 48.82 3500+00 53.26 56.26 56.26 49.31 3449+00 52.72 55.72 55.72 48.84 3501+00 53.34 56.34 56.34 49.40 3450+00 52.73 55.73 55.73 48.86 3502+00 53.46 56.46 56.46 49.54 3451+00 52.75 55.75 55.75 48.87 3503+00 53.58 56.58 56.58 49.68 3452+00 52.77 55.77 55.77 48.89 3504+00 53.70 56.70 56.70 49.82 3453+00 52.79 55.79 55.79 48.91 3505+00 53.72 56.72 56.72 49.86 3454+00 52.81 55.81 55.81 48.93 3506+00 53.68 56.68 56.68 49.84 3455+00 52.83 55.83 55.83 48.95 3507+00 53.64 56.64 56.64 49.83 3456+00 52.86 55.86 55.86 48.97 3508+00 53.61 56.61 56.61 49.81 3457+00 52.88 55.88 55.88 48.99 3509+00 53.73 56.73 56.73 49.91 3458+00 52.90 55.90 55.90 49.01 3510+00 53.94 56.94 56.94 50.06 3459+00 52.92 55.92 55.92 49.04 3511+00 54.15 57.15 57.15 50.22 3460+00 52.95 55.95 55.95 49.06 3512+00 54.34 57.34 57.34 50.38 3461+00 52.97 55.97 55.97 49.08 3513+00 54.51 57.51 57.51 50.55 3462+00 52.99 55.99 55.99 49.10 3514+00 54.67 57.67 57.67 50.72 3463+00 53.01 56.01 56.01 49.12 3515+00 54.80 57.80 57.80 50.85 3464+00 53.04 56.04 56.04 49.14 3516+00 54.85 57.85 57.85 50.89 3465+00 53.06 56.06 56.06 49.16 3517+00 54.90 57.90 57.90 50.94 3466+00 53.06 56.06 56.06 49.17 3518+00 55.04 58.04 58.04 51.09 3467+00 53.05 56.05 56.05 49.16 3519+00 55.15 58.15 58.15 51.21 D-6
Table D-1. ULDC Hydraulic Parameter Profiles, American River North Levee (cont.) Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
SVRP
(feet)
3520+00 55.21 58.21 58.21 51.29 3552+00 57.20 60.20 60.20 54.90 3521+00 55.28 58.28 58.28 51.38 3553+00 57.29 60.29 60.29 55.03 3522+00 55.35 58.35 58.35 51.45 3554+00 57.38 60.38 60.38 55.17 3523+00 55.40 58.40 58.40 51.52 3555+00 57.47 60.47 60.47 55.30 3524+00 55.47 58.47 58.47 51.60 3556+00 57.56 60.56 60.56 55.44 3525+00 55.47 58.47 58.47 51.63 3557+00 57.64 60.64 60.64 55.57 3526+00 55.49 58.49 58.49 51.66 3558+00 57.74 60.74 60.74 55.68 3527+00 55.52 58.52 58.52 51.70 3559+00 57.85 60.85 60.85 55.79 3528+00 55.60 58.60 58.60 51.81 3560+00 57.95 60.95 60.95 55.90 3529+00 55.69 58.69 58.69 51.94 3561+00 58.05 61.05 61.05 56.01 3530+00 55.82 58.82 58.82 52.15 3562+00 58.15 61.15 61.15 56.12 3531+00 55.92 58.92 58.92 52.31 3563+00 58.21 61.21 61.21 56.20 3532+00 56.00 59.00 59.00 52.41 3564+00 58.24 61.24 61.24 56.26 3533+00 56.09 59.09 59.09 52.52 3565+00 58.26 61.26 61.26 56.32 3534+00 56.20 59.20 59.20 52.65 3566+00 58.34 61.34 61.34 56.42 3535+00 56.30 59.30 59.30 52.78 3567+00 58.49 61.49 61.49 56.58 3536+00 56.35 59.35 59.35 52.85 3568+00 58.64 61.64 61.64 56.74 3537+00 56.40 59.40 59.40 52.92 3569+00 58.79 61.79 61.79 56.89 3538+00 56.47 59.47 59.47 53.03 3570+00 58.95 61.95 61.95 57.03 3539+00 56.54 59.54 59.54 53.14 3571+00 59.11 62.11 62.11 57.17 3540+00 56.62 59.62 59.62 53.24 3572+00 59.27 62.27 62.27 57.31 3541+00 56.66 59.66 59.66 53.32 3573+00 59.43 62.43 62.43 57.45 3542+00 56.69 59.69 59.69 53.38 3574+00 59.57 62.57 62.57 57.58 3543+00 56.71 59.71 59.71 53.44 3575+00 59.65 62.65 62.65 57.69 3544+00 56.74 59.74 59.74 53.52 3576+00 59.73 62.73 62.73 57.79 3545+00 56.76 59.76 59.76 53.63 3577+00 59.82 62.82 62.82 57.90 3546+00 56.78 59.78 59.78 53.75 3578+00 59.90 62.90 62.90 58.00 3547+00 56.80 59.80 59.80 53.86 3579+00 59.98 62.98 62.98 58.11 3548+00 56.76 59.76 59.76 53.99 3580+00 60.14 63.14 63.14 58.21 3549+00 56.73 59.73 59.73 54.14 3581+00 60.29 63.29 63.29 58.31 3550+00 56.87 59.87 59.87 54.39 3582+00 60.45 63.45 63.45 58.42 3551+00 57.04 60.04 60.04 54.66 3582+80 60.58 63.58 63.58 58.50 D-7
Table D-2. ULDC Hydraulic Parameter Profiles, Arcade Creek South Levee Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
4000+00 37.10 40.10 40.10 4037+00 37.77 40.77 40.77 4074+00 38.48 41.48 41.48 4001+00 37.44 40.44 40.44 4038+00 37.78 40.78 40.78 4075+00 38.50 41.50 41.50 4002+00 37.53 40.53 40.53 4039+00 37.78 40.78 40.78 4076+00 38.52 41.52 41.52 4003+00 37.63 40.63 40.63 4040+00 37.78 40.78 40.78 4077+00 38.54 41.54 41.54 4004+00 37.64 40.64 40.64 4041+00 37.78 40.78 40.78 4078+00 38.56 41.56 41.56 4005+00 37.64 40.64 40.64 4042+00 37.78 40.78 40.78 4079+00 38.58 41.58 41.58 4006+00 37.65 40.65 40.65 4043+00 37.79 40.79 40.79 4080+00 38.60 41.60 41.60 4007+00 37.65 40.65 40.65 4044+00 37.79 40.79 40.79 4081+00 38.64 41.64 41.64 4008+00 37.66 40.66 40.66 4045+00 37.79 40.79 40.79 4082+00 38.67 41.67 41.67 4009+00 37.66 40.66 40.66 4046+00 37.79 40.79 40.79 4083+00 38.70 41.70 41.70 4010+00 37.66 40.66 40.66 4047+00 37.80 40.80 40.80 4084+00 38.74 41.74 41.74 4011+00 37.67 40.67 40.67 4048+00 37.80 40.80 40.80 4085+00 38.80 41.80 41.80 4012+00 37.67 40.67 40.67 4049+00 37.81 40.81 40.81 4086+00 38.87 41.87 41.87 4013+00 37.67 40.67 40.67 4050+00 37.81 40.81 40.81 4087+00 38.95 41.95 41.95 4014+00 37.67 40.67 40.67 4051+00 37.82 40.82 40.82 4088+00 39.02 42.02 42.02 4015+00 37.67 40.67 40.67 4052+00 37.82 40.82 40.82 4089+00 39.10 42.10 42.10 4016+00 37.68 40.68 40.68 4053+00 37.83 40.83 40.83 4090+00 39.16 42.16 42.16 4017+00 37.68 40.68 40.68 4054+00 37.85 40.85 40.85 4091+00 39.22 42.22 42.22 4018+00 37.68 40.68 40.68 4055+00 37.86 40.86 40.86 4092+00 39.28 42.28 42.28 4019+00 37.68 40.68 40.68 4056+00 37.88 40.88 40.88 4093+00 39.33 42.33 42.33 4020+00 37.68 40.68 40.68 4057+00 37.89 40.89 40.89 4094+00 39.39 42.39 42.38 4021+00 37.69 40.69 40.69 4058+00 37.90 40.90 40.90 4095+00 39.43 42.43 42.38 4022+00 37.69 40.69 40.69 4059+00 37.91 40.91 40.91 4096+00 39.46 42.46 42.38 4023+00 37.69 40.69 40.69 4060+00 37.92 40.92 40.92 4097+00 39.48 42.48 42.38 4024+00 37.69 40.69 40.69 4061+00 37.92 40.92 40.92 4098+00 39.51 42.51 42.38 4025+00 37.70 40.70 40.70 4062+00 37.93 40.93 40.93 4099+00 39.54 42.54 42.39 4026+00 37.70 40.70 40.70 4063+00 37.93 40.93 40.93 4100+00 39.70 42.70 42.41 4027+00 37.71 40.71 40.71 4064+00 37.92 40.92 40.92 4101+00 39.96 42.96 42.44 4028+00 37.71 40.71 40.71 4065+00 38.07 41.07 41.07 4102+00 40.21 43.21 42.47 4029+00 37.71 40.71 40.71 4066+00 38.12 41.12 41.12 4103+00 40.47 43.47 42.50 4030+00 37.72 40.72 40.72 4067+00 38.13 41.13 41.13 4104+00 40.73 43.73 42.54 4031+00 37.74 40.74 40.74 4068+00 38.14 41.14 41.14 4105+00 40.95 43.95 42.57 4032+00 37.74 40.74 40.74 4069+00 38.34 41.34 41.34 4106+00 41.12 44.12 42.60 4033+00 37.74 40.74 40.74 4070+00 38.37 41.37 41.37 4107+00 41.30 44.30 42.63 4034+00 37.74 40.74 40.74 4071+00 38.39 41.39 41.39 4108+00 41.47 44.47 42.66 4035+00 37.74 40.74 40.74 4072+00 38.42 41.42 41.42 4109+00 41.65 44.65 42.69 4036+00 37.73 40.73 40.73 4073+00 38.45 41.45 41.45 4110+00 41.82 44.82 42.73 D-8
Table D-3. ULDC Hydraulic Parameter Profiles, NEMDC East Levee Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
Levee
Station
(feet)
DWSE
(feet)
MTOL
(feet)
HTOL
(feet)
2986+49 35.64 38.64 38.64 3020+00 36.29 39.29 39.29
2987+00 35.65 38.65 38.65 3021+00 36.32 39.32 39.32
2988+00 35.69 38.69 38.69 3022+00 36.39 39.39 39.39
2989+00 35.72 38.72 38.72 3023+00 36.44 39.44 39.44
2990+00 35.73 38.73 38.73 3024+00 36.46 39.46 39.46
2991+00 35.74 38.74 38.74 3025+00 36.49 39.49 39.49
2992+00 35.76 38.76 38.76 3026+00 36.52 39.52 39.52
2993+00 35.77 38.77 38.77 3027+00 36.55 39.55 39.55
2994+00 35.78 38.78 38.78 3028+00 36.57 39.57 39.57
2995+00 35.80 38.80 38.80 3029+00 36.60 39.60 39.60
2996+00 35.81 38.81 38.81 3030+00 36.63 39.63 39.63
2997+00 35.82 38.82 38.82 3031+00 36.65 39.65 39.65
2998+00 35.84 38.84 38.84 3032+00 36.67 39.67 39.67
2999+00 35.85 38.85 38.85 3033+00 36.70 39.70 39.70
3000+00 35.86 38.86 38.86 3034+00 36.72 39.72 39.72
3001+00 35.92 38.92 38.92 3035+00 36.74 39.74 39.74
3002+00 35.93 38.93 38.93 3036+00 36.77 39.77 39.77
3003+00 35.94 38.94 38.94 3037+00 36.79 39.79 39.79
3004+00 35.95 38.95 38.95 3038+00 36.82 39.82 39.82
3005+00 35.96 38.96 38.96 3039+00 36.85 39.85 39.85
3006+00 35.96 38.96 38.96 3040+00 36.87 39.87 39.87
3007+00 35.97 38.97 38.97 3041+00 36.90 39.90 39.90
3008+00 35.99 38.99 38.99 3042+00 36.93 39.93 39.93
3009+00 36.02 39.02 39.02 3043+00 36.95 39.95 39.95
3010+00 36.05 39.05 39.05 3044+00 36.98 39.98 39.98
3011+00 36.08 39.08 39.08 3045+00 36.99 39.99 39.99
3012+00 36.11 39.11 39.11 3046+00 37.01 40.01 40.01
3013+00 36.14 39.14 39.14 3047+00 37.03 40.03 40.03
3014+00 36.17 39.17 39.17 3048+00 37.05 40.05 40.05
3015+00 36.20 39.20 39.20 3049+00 37.06 40.06 40.06
3016+00 36.22 39.22 39.22 3050+00 37.08 40.08 40.08
3017+00 36.24 39.24 39.24 3051+00 37.10 40.10 40.10
3018+00 36.26 39.26 39.26 3051+61 37.10 40.10 40.10
3019+00 36.28 39.28 39.28

APPENDIX B
___________________________________________________________________________________

LIST OF ATTACHMENTS
MBK, Engineers. “American River North Levee System: Levee Geometry Analysis (ULDC). Sheets 5 through 10.

American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 1 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 2 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 3 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 4 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 5 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 6 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 7 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 8 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 9 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 10 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 11 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 12 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 13 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 14 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 15 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 16 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 17 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx American River North Levee System: Levee Geometry Analysis (ULDC) Profile Sheet No. 18 of 18 R:\_Flood Control\SAFCA\FEMA_ULDC\ULOP\ULDC Cert - American North Basin\7.8 Levee Geometry\Cross-sections\ARN Levee Geometry - ULDC Feb 2024.docx

APPENDIX C
___________________________________________________________________________________

LIST OF ATTACHMENTS
“Seismic Performance Summary Report North Area Streams Levee Areas, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento County, California.” Dated February 12, 2024. Revised September 10, 2024. 24001006.001A/SAC24R164096_R1 Page i of vi February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

SEISMIC PERFORMANCE SUMMARY REPORT

NORTH AREA STREAMS LEVEE AREAS

ULDC & FEMA LEVEE CERTIFICATION PROJECT

SACRAMENTO AREA FLOOD CONTROL AGENCY LEVEE SYSTEMS

SACRAMENTO COUNTY, CALIFORNIA
FEBRUARY 12, 2024
(REVISEDS SEPTEMBER 10, 2024)
Copyright 2024 Kleinfelder
All Rights Reserved
24001006.001A/SAC24R164096_R1 Page ii of vi February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
February 12, 2024
(Revised September 10, 2024)
File No.: 24001006.001A
Mr. Pete Ghelfi, PE
Director of Engineering
Sacramento Area Flood Control Agency
1325 J Street, Suite 1700
Sacramento, CA 95814
Subject: Seismic Performance Summary Report
North Area Streams Levee Areas
ULDC & FEMA Levee Certification Project
Sacramento Area Flood Control Agency Levee Systems
Sacramento County, California
Kleinfelder Project # 24001006.001A
Dear Mr. Ghelfi:

Kleinfelder has been tasked by the Sacramento Area Flood Control Agency (SAFCA) with evaluating the seismic vulnerability of the Sacramento area levees located in Sacramento and Sutter Counties, California in support of the Urban Levee Design Criteria (ULDC) (DWR, 2012) level certification. For the evaluation, the Sacramento area levees have been divided into three areas - Natomas Basin, American River/South Sacramento Basin, and North Area Streams (NAS). A separate Seismic Performance Summary Report (SPSR) will be prepared for each of the three areas.

The purpose of this SPSR is to document Kleinfelder’s findings, present evaluation results, and present anticipated seismic segment performance for the NAS area levees. This document provides the analysis to support the development of a forthcoming Post-Earthquake Response Plan (PERP).

NAS area includes Dry Creek North (DCNL) and South Levees (DCSL), Arcade Creek North (ACNL) and Arcade Creek South Levees (ACSL), Natomas East Main Drainage Canal East Levee (NEMDCEL), and American River North Levee (ARNL) located within Sacramento County California as shown on Figure 1-

1. 24001006.001A/SAC24R164096_R1 Page iii of vi February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
This report has been prepared consistent with the requirements of the approved scope of work for the subject project outlined in Kleinfelder’s proposal dated May 5, 2023.

Sincerely,
KLEINFELDER, INC.

Meredith Beswick PE, PG Zia Zafir PE, GE
Senior Geologist Sr. Principal Geotechnical Engineer
Reviewed By:

Timothy A. Williams, PE, GE
Sr. Principal Geotechnical Engineer
CC: Mr. Pro Mitra, PE/MBK Engineers ([email protected]) Ms. Becky Money, PE/MBK Engineers ([email protected]) 24001006.001A/SAC24R164096_R1 Page iv of vi February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

TABLE OF CONTENTS

SECTION PAGE
1 INTRODUCTION .........................................................................................................................1

1.1 PURPOSE AND SCOPE ......................................................................................................... 1

1.2 BACKGROUND..................................................................................................................... 1

1.3 REFERENCED REPORTS........................................................................................................ 2

1.4 SEISMIC VULNERABILITY EVALUATION METHODOLOGY.................................................... 2

1.4.1 Preliminary Work ................................................................................................... 3

1.4.2 Phase 1: Screening Review of Existing Analysis..................................................... 3

1.4.3 Phase 2: Targeted Evaluation ................................................................................ 4

1.4.4 Seismic Vulnerability.............................................................................................. 4 2 GEOLOGY AND GEOMORPHOLOGY.............................................................................................8

2.1 REGIONAL GEOLOGIC SETTING........................................................................................... 8

2.2 LOCAL GEOLOGY ................................................................................................................. 9

2.2.1 Surficial Geology .................................................................................................... 9

2.2.2 Generalized Near Surface Stratigraphy ............................................................... 11

2.3 SEISMOTECTONIC SETTING............................................................................................... 12 3 GROUND MOTION HAZARD ANALYSIS ......................................................................................14

3.1 SEISMIC HAZARD ANALYSIS .............................................................................................. 14

3.1.1 Seismic Analysis Results....................................................................................... 15 4 PREVIOUS EVALUATION...........................................................................................................16

4.1 SUMMARY......................................................................................................................... 16

4.1.1 General................................................................................................................. 16

4.2 SEISMIC ANALYSIS WATER SURFACE ELEVATIONS ........................................................... 17 5 CURRENT EVALUATION ............................................................................................................18

5.1 SEISMIC EVALUATION SEGMENT SELECTION ................................................................... 18

5.1.1 Liquefaction Analysis of ULDC Segments............................................................. 18

5.2 VULNERABILITY CLASSIFICATIONS FOR TARGETED SEGMENTS........................................ 20

5.2.1 Segment AR-12 .................................................................................................... 20

5.2.2 Segment AR-14 .................................................................................................... 21

5.2.3 Segment NMDE-3 ................................................................................................ 23 6 SEISMIC PERFORMANCE...........................................................................................................24

6.1 SUMMARY......................................................................................................................... 24 7 LIMITATIONS ...........................................................................................................................25 8 REFERENCES ............................................................................................................................26 24001006.001A/SAC24R164096_R1 Page v of vi February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
TABLES

3.1 Seismic Hazard Analysis Site Parameters

3.2 Probabilistic Peak Horizontal Acceleration and Controlling Earthquake Magnitude

4.1 Phase 1 - Seismic Vulnerability Results Screening

5.1.1 Liquefaction Layer Changes for Targeted Segments

5.1.2 Liquefaction Factor of Safety Changes for Targeted Segments

5.2.1 2015 URS Post-Seismic Stability Analysis Factors of Safety for Targeted Segments

5.2.2 Material Properties for Segment AR-14 Post-Seismic Stability Analysis

5.2.3 Segment AR-14 Post-Seismic Slope Stability Factors of Safety

5.2.4 2015 URS Post-Seismic Stability Analysis Factors of Safety for Segment NMDE-2

6.1 Seismic Vulnerability Classifications for North Area Streams Levees

FIGURES
1-1 Site Map
1-2 Table 6-1 from DWR Guidance Document, Section 6.4
1-3 Flow Chart
2-1 Regional Geology
2-2 North Area Streams Levees Geologic Map
2-3 American River North Levee Geologic Map

APPENDIX
A Seismic Technical Approach Memo
B Ground Motion Parameter Selection Memo
C Section 6, Seismic Analysis, Guidance Document for Geotechnical Analyses, Urban Levee Evaluations Project
D Updated SPT-Based Liquefaction Calculations for Targeted Segments E Post-Seismic Slope Stability Analysis for Segment AR-14 F Original URS Liquefaction Spreadsheet Analyses
24001006.001A/SAC24R164096_R1 Page vi of vi February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

REPORT ACRONYMS
______________________________________________________________________________________________ 200-year 200-year median (i.e., flood recurrence period) ACNL Arcade Creek North Levee
ACSL Arcade Creek South Levee
ARCF American River Common Features
ARNL American River North Levee
DCNL Dry Creek North Levee
DCSL Dry Creek South Levee
DRMS Delta Risk Management Strategy
DWR California Department of Water Resources
FEMA Federal Emergency Management Agency
FOS Factor of Safety
FWLA Fugro William Lettis & Associates, Inc.

GER Geotechnical Evaluation Report
GMHA Ground Motion Hazard Analysis
KLF Kleinfelder
km Kilometer
Mw Earthquake Magnitude
NASL North Area Streams Levees
NEMDC Natomas East Main Drainage Canal
NEMDCEL Natomas East Main Drainage Canal – East Levee
PHA Peak Horizontal Acceleration
SAFCA Sacramento Area Flood Control Agency
SETAM Seismic Evaluation Technical Analysis Memorandum
SNGV Sierra Nevada-Great Valley block
SPSR Seismic Performance Summary Report
SPT Standard Penetration Test
ULDC Urban Levee Design Criteria
ULE Urban Levee Evaluation
URS URS Corporation
USACE United States Army Corps of Engineers
WUS Western United States
24001006.001A/SAC24R164096_R1 Page 1 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
1 INTRODUCTION
___________________________________________________________________________________

1.1 PURPOSE AND SCOPE
Kleinfelder has been tasked by the Sacramento Area Flood Control Agency (SAFCA) with evaluating the seismic vulnerability of the Sacramento area levees located in Sacramento and Sutter Counties, California in support of the Urban Levee Design Criteria (ULDC) (DWR, 2012) level certification. For the evaluation, the Sacramento area levees have been divided into three areas - Natomas Basin, American River/South Sacramento Basin, and North Area Streams (NAS). A separate Seismic Performance Summary Report (SPSR) will be prepared for each of the three areas.

1. This report has been prepared consistent with the requirements of the approved scope of work for the subject project outlined in Kleinfelder’s proposal dated May 5, 2023.

1.2 BACKGROUND
NAS levees in the greater Sacramento area were constructed over a period of years, with original construction of many reaches started around the turn of the last century. Since that time many changes have been made to the system to improve the system to meet modern flood control standards, to accommodate changes in land use, and to make the system more resilient to impacts from climate change and other factors.

Recently as part of modernization efforts, The American River Common Features (ARCF) Project improvements were authorized by the Federal Government for construction by Section 1401(2)(7) of the Water Infrastructure Improvements for the Nation Act of 2016 (Pub. L. No. 114-322, § 1401(2)(7), 130 24001006.001A/SAC24R164096_R1 Page 2 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Stat. 1708, 1710 (2016)). The ARCF authorized work is nearing completion under the oversight of the U.S. Army Corps of Engineers (USACE) in cooperation with SAFCA and the California Department of Water Resources. Other locally sponsored modernization efforts and repair work are also or will soon be completed. As such, it is expected that by or about 2026, SAFCA will be working to apply for FEMA certification and will as part of that effort show compliance with ULDC requirements.

To better understand the potential flood risk to urban areas of California posed by levees, the California Department of Water Resources (DWR) conducted the Urban Levee Evaluations (ULE) project. As part of this effort, URS classified the seismic vulnerability of the NAS levees in the Geotechnical Evaluation Reports for the American River Study Area (URS, 2015a) and the NEMDC East Study Area (URS, 2015c).

1.3 REFERENCED REPORTS
The following reports were reviewed in support of this NAS SPSR:
• “ULE Geotechnical Evaluation Report (GER) Volume 1 and 2, American River Study Area, Urban Levee Evaluations Project, Contract 4600008101,” dated January 2015 (Issue date: 01-2015), URS (2015a).
• “ULE Geotechnical Evaluation Report Volume 2, Remedial Alternatives, NEMDC East Study Area, Urban Levee Evaluations Project, Contract 4600008101,” dated April 2015 (Issue date: 04-2015), URS (2015c).

1.4 SEISMIC VULNERABILITY EVALUATION METHODOLOGY
The seismic vulnerability evaluation was performed in accordance with Kleinfelder’s Seismic Evaluation Technical Approach Memorandum (Kleinfelder, 2023a) (SETAM) contained in Appendix A, which is generally consistent with the Urban Levee Evaluations Project Guidance Document for Geotechnical Analysis (URS, 2015b) (Guidance Document) Section 6, Seismic Analysis for intermittently loaded levees1. High, Moderate, and Low Vulnerability classifications from the Guidance Document (URS, 1 The ULDC requires classifying the levee as frequently loaded or intermittently loaded. A frequently loaded levee is defined in the ULDC as a levee with water at least one foot above the landside levee toe for more than 36 days in a year. As stated in the ULDC Geotechnical Results Summary North Area Streams (Kleinfelder, 2016) and in the ULE Geotechnical Evaluation Report Volume 1 and 2 American River Study Area (URS, 2015b), the study area levees generally do not contain water above the landside toe for this time interval. Therefore, the levees within the study area are considered intermittently loaded for this study.
24001006.001A/SAC24R164096_R1 Page 3 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
2015b) will be based on the seismic deformation estimates, see Figure 1-2 in Section 1.4.4, below. The steps for evaluating and classifying the levee are outlined in the SETAM and are described briefly below.

Figure 1-3 presents a flow chart describing the evaluation criteria.

1.4.1 Preliminary Work
Kleinfelder performed a review of the existing geotechnical analysis and subsurface data. During this process, seismic segment data gaps were identified and the updated peak horizontal acceleration (PHA) and magnitude values were developed.

Previous development of ground motion parameters in the area was performed by URS in 2007 as part of the Delta Risk Management Strategy (DRMS), which was updated and expanded on in 2012 by URS as part of the DWR ULE project. Updated ground motion parameters were developed following assumptions of this previous work, and detailed methodology is presented in our Seismic Evaluation Ground Motion Parameter Selection Memorandum (GMPSM) (Kleinfelder, 2023b), which is included in Appendix B. A probabilistic seismic hazard analysis was performed to determine PHA and earthquake magnitude as discussed in the GMPSM and Section 3, Ground Motion Hazard Analysis (GMHA), of this report.

1.4.2 Phase 1: Screening Review of Existing Analysis
The levees are organized by selection of “segments” instead of reaches due to the variable nature of subsurface conditions under levees. Segments may overlap multiple reaches or reaches may be subdivided into multiple segments. Levee segments, which were based on portions of the levees with similar soil types and liquefaction results, and analysis sections for each segment for seismic evaluation were developed for the 2015 ULE evaluations and were adopted for this study. Levee segments are shown on Figure 1-1.

The screening process was performed to identify which analysis sections were classified as Low, Medium, and High Vulnerability in 2015. All sections identified as High Vulnerability were not considered for reanalysis because they would remain High Vulnerability since the updated ground motions were slightly higher than those used for the ULE evaluations. Low and Medium Vulnerability segments were reanalyzed based on the updated ground motions described in the GMPSM in Appendix B. Analysis sections determined to be non-critical for seismic performance were not used in the current analyses and are not presented in report.
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Kleinfelder performed probabilistic seismic hazard analyses at select control points in the North Area Streams area, as discussed in the GMPSM (Kleinfelder, 2023b). Newly developed PHAs and earthquake magnitudes from these analyses for critical sections were compared to ground motion parameters from previous reports. No further analysis was required for analysis sections where any of the below conditions are true:

1. The new PHA and/or earthquake magnitude are lower than the original PHA and/or earthquake magnitude and the original analysis is determined to be adequate.

2. The original analysis determined the section is not susceptible to deformation and the new PHA and/or earthquake magnitude are not higher than the original analysis PHA and/or earthquake magnitude.

3. The analysis section is found to have High Vulnerability or Flow Failure based on the original PHA and earthquake magnitude.

1.4.3 Phase 2: Targeted Evaluation
A targeted evaluation was required for critical sections under two conditions, as follows:

1. The original analysis classified the section as Low or Medium Vulnerability.

2. The new earthquake magnitude and/or PHA exceeds the original magnitude/PHA used in the 2015 analysis (except for High Vulnerability).

High, Medium, and Low Vulnerability classifications were based on the seismic deformation estimates from the Guidance Document (URS, 2015a). As explained in Section 1.4.2, all segments classified as High Vulnerability in the Phase 1 screening process were not analyzed, and the High Vulnerability classification remained unchanged for this study.

1.4.4 Seismic Vulnerability
The following steps were involved in assessing seismic vulnerability, Step numbers are associated with Key Steps described in Figure 6-1 of the Guidance Document (URS, 2015b); see Appendix C. These steps were performed for the ULE American River Study Area GER (URS, 2015a) and the NEMDC East Study 24001006.001A/SAC24R164096_R1 Page 5 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Area (URS, 2015c) and were reviewed by Kleinfelder for this study. Liquefaction analysis spreadsheets prepared for the ULE GER were provided to Kleinfelder by DWR for review.

Step 1. Kleinfelder performed a liquefaction analysis using revised PHA and earthquake magnitude values. The URS SPT-based liquefaction spreadsheets were used to delineate zones of liquefaction.

Based on the results of liquefaction, any additional cross sections were identified for analysis.

The analysis cross sections developed for the 2015 ULE project were used for this study where relevant.

Step 2. For selected cross sections, FOS against flow failure were estimated using residual strength for liquefiable materials and static slope stability analysis. If FOS was less than 1, the section was classified as “High Vulnerability” and no further analysis was needed.

If FOS against flow failure was greater than 1.3, the analysis section was classified as “Low Vulnerability”, unless analysis for volumetric strain resulted in a higher vulnerability class.

Kleinfelder and others have previously performed extensive slope failure modeling along the levee alignments using SLOPE/W, a two-dimensional finite element computer modeling, a package included in the GEOSTUDIO software package, which was developed by Bentley Systems, Inc. Where necessary, these models were updated to the current version of GEOSTUDIO (2023.1.2) and utilized for Targeted Flow Failure analyses. Idealized soil properties were based on previous investigations and generalized parameters from the Guidance Document (URS, 2015a). Water surface elevations for seismic flow failure analyses were the higher of either average summer or average winter water surfaces, in accordance with the Guidance Document (URS, 2015a).

Slope failure analyses considered all potential failure modes, including:
• Waterside and landside
• Deep and shallow
• Circular and wedge-shaped
Step 3. If FOS against flow failure was between 1.0 and 1.3, a simplified seismic deformation analysis was performed on the section. This involved computing a maximum horizontal seismic coefficient (Kmax) and performing a pseudo-static stability analysis using a horizontal seismic 24001006.001A/SAC24R164096_R1 Page 6 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
coefficient of 50% of the maximum value. This analysis was performed using the same updated SLOPE/W models used in Step 2. If the resulting FOS greater than 1.0, the section was classified as “Low Vulnerability”.

Yield acceleration (Ky) values were then estimated using pseudo-static analyses using the same SLOPE/W models used in Step 2. Yield acceleration was defined as the minimum horizontal acceleration resulting in a just-stable slope condition, i.e. FOS = 1.0. Yield acceleration was developed for each potential failure mode.

A vertical Newmark-type deformation analysis was performed based on the Kmax and Ky values determined above. The calculated Newmark displacement was reduced by 30% for estimation of freeboard loss.

Volumetric settlement was considered for sections with potentially liquefiable soils thicker than 20 feet. Previous work performed by URS on ULE considered (N1)60-cs blow counts less than 15 as liquefiable and subject to volumetric settlement. This blow count criteria was evaluated against new research and revised, if warranted.

Seismic vulnerability classification was determined by calculating freeboard loss as the sum of Newmark-type vertical deformation and volumetric settlement (if applicable). Freeboard loss was evaluated as a percentage of levee height (as measured from hinge point on the landside toe). Engineering judgment was used to determine damage to internal levee structures, and the seismic vulnerability class was evaluated based on Table 6-1 from the Guidance Document (URS, 2015b) shown below in Figure 1-2.

Figure 1-2: Table 6-1 from DWR Guidance Document, Section 6.41 24001006.001A/SAC24R164096_R1 Page 7 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Step 4. Advanced seismic deformation analyses as described in Appendix C only apply to frequently loaded levees and were not applicable to this study.

The stages of our evaluation were described in detail in our SETAM (KLF, 2023a) as well as Section 6 of the Guidance Document (DWR, 2015b).
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2 GEOLOGY AND GEOMORPHOLOGY
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2.1 REGIONAL GEOLOGIC SETTING
The study area is located within the southern portion of the Sacramento Valley, within the Great Valley geomorphic province. The Great Valley province is a north-south trending 400-mile by 50-mile long alluvial plain in central California comprised of the Sacramento Valley in the north and the San Joaquin Valley in the south. The Sacramento Valley contains thousands of feet of accumulated fluvial, overbank, and alluvial fan deposits derived from erosion of the adjacent Sierra Nevada mountains to the east, northern Coast Range mountains to the west, and Klamath and Cascade mountains to the north. These deposits are primarily comprised of Quaternary and Tertiary age (present day to 56 million years ago) alluvial deposits and include clays, silts, sands, and gravels. The alluvial deposits thin out at the margins of the Great Valley province, exposing the underlying bedrock units. The Foothills Metamorphic Belt and the basement complex of the Sierra Nevada Batholith to the east are exposed along the eastern boundary of the valley. Sedimentary and mélange bedrock of the northern Coast Range mountains are exposed to the west. Meta-sedimentary, mélange, igneous, and volcanic bedrock of the Klamath and Cascade mountains are exposed to the north.

Geologic maps covering the study area on a regional scale were reviewed as a part of this study.

Published maps include:
• Wagner et al. “Geologic Map of the Sacramento Quadrangle, California. 1:250,000. Dated 1981. • Helley and Harwood. “Geologic Map of the late Cenozoic Deposits of the Sacramento Valley and Northern Sierran Foothills, California.” Sheet 1 of 5. 1:62,500. Dated 1985. • Gutierrez, C.I. “Preliminary Geologic Map of the Sacramento 30’ X 60’ Quadrangle, California,” Scale 1:100,000. Dated 2011.

Wagner et al. provides a generalized regional context of the geologic units within and surrounding the study area. Guitierrez provides an updated version of the Helley and Hardwood map with more detail of the alluvial deposits within and surrounding the study area than Wagner et al. In general, the three maps present the geologic units consistently in the vicinity of the study area. Figure 2-1 shows the study area on the Wagner et al. geologic map.
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2.2 LOCAL GEOLOGY
A review of the local geology was performed using larger scale geologic maps covering the study area and comparing to the previously discussed regional geologic maps and existing subsurface data. Based on this review the local geology at depth is summarized in the sections below.

Surficial geology maps were previously prepared by Fugro William Lettis Associates (FWLA) of the study area on two separate maps.
• “Surficial Geologic Map of the American River Study Area.” Scale 1:20,000. Dated 2008. (FWLA, 2008)
• “Surficial Geologic Map of the NEMDC East Study Area.” Scale 1:20,000. Dated 2011. (FWLA, 2011)
The maps were prepared by reviewing existing geologic maps of the area, topography, and aerial photographs from 1937. The FWLA maps provide more detail geologic mapping within the study area.

Figure 2-2 shows Dry Creek, Arcade Creek, and NEMDC study are levee alignments plotted on the FWLA 2008 geology Map. Figure 2-3 presents the 2011 FWLA geology map for American River.

2.2.1 Surficial Geology
The major surficial geologic deposits within the FWLA are summarized below with the geologic unit symbols used by FWLA (2008 and 2011).
• Cultural Deposits (L, RR, ML): Historical Levee (L), Railroad Embankment (RR), Road Embankment (R), and Made Land (ML); made of artificial fill (Circa 1937 except Made Land); The Made Land is described as fill material of local and exotic sources, sand, silt, organics, garbage, etc. Historical levee deposits are generally mapped along Dry Creek, Arcade Creek, NEMDCEL, and American River. Railroad are mapped along the Union Pacific Railroad tracks that cross American River and parallel NEMDCEL. Made land is mapped sporadically along and within the American River.
• Borrow Pit (BP): area mapped where the existing fill was removed as noted from the 1937 aerial photographs. The material was likely used in levee fill construction. Borrow pits are mapped 24001006.001A/SAC24R164096_R1 Page 10 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
along NEMDC channel from the confluence with American River to north of the intersection with Arcade Creek. Borrow pit is also mapped along the waterside toe of ARNL. • Vernal Pool (Vp): seasonally submerged or saturated depression usually indicative of underlying hardpan. Mapped along much of DCSL and ACNL.
• Historical Overbank Deposits (Rob): sand, silt, and clay; deposited during high-stage water flow, overtopping channel banks. Mapped along ARNL.
• Historical Channel Deposits (Rch): well-sorted sands and fine gravels. Predominantly mapped along DCNL, Dry Creek floodway, ACNL, and ARNL.
o Historical Channel Bar Deposits (Rb): fine gravel, sand, and silt deposited at or along channel lateral margins. Mapped along portions of ARNL. o Historical Point Bar Deposits (Rpb): well-sorted sand with minor amounts of silt and clay.

Mapped along ARNL.
• Historical Cut-off Channel Deposits (Rcu): occur on insides of meander bends within the river channel. Mapped along portions of ARNL.
• Historical Distributary Channel Deposits (Rdc): sand, silt, clay and trace gravel. Mapped along ARNL.
• Historical Slough Deposits (Rsl): sand, silt, and clay, fining upward, low-energy channel deposits.

Mapped along minimal portions of ARNL.
• Holocene Alluvial Fan Deposits (Hfy): sand, silt, and clay. Mapped west of NEMDC at the intersections of Arcade Creek, Magpie Creek, Dry Creek, and American River. • Holocene Overflow Channel Deposits (Hofc): vertically stratified sand, silt, and clay in channels occupied when high-stage water overtops channel banks. Mapped north of and parallel to ARNL.
• Holocene Channel Deposits (Hch): sorted sands and silts, fining upward. Mapped along NEMDCEL, ACSL, and ARNL.
• Holocene Slough Basin Deposits (Hsb): sand, silt, and cay; fining upwards, ponded, low-energy channel deposits. Mapped along portions of ARNL.
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• Holocene Slough Deposits (Hsl): Holocene slough deposits; sand, silt, and clay, fining upward, low-energy channel deposits. Mapped along portions of ARNL. • Holocene Basin Deposits (Hn): fine sand, silt, and clay. Mapped in the area of the historical Magpie Creek intersection with NEMDCEL and where the current Magpie Creek concrete-lined channel, I-80 bridges, and pump station intersect NEMDCEL. • Holocene Marsh Deposits (Hs): silt and clay, possibly with organic-rich beds; perennially or seasonally submerged. Mapped in the area of the historical Magpie Creek intersection with NEMDCEL and where the current Magpie Creek concrete-lined channel, I-80 bridges, and pump station intersect NEMDCEL; also mapped along minimal portion of ARNL. • Holocene Alluvial Deposits (Ha): undifferentiated; sand, silt, and minor lenses of gravel. Mapped along NEMDCEL south of Arcade Creek, along ACSL, and ARNL. • Modesto Formation (Qmu, Qml): Late Pleistocene (estimated 12,000 to 45,000 years of age) alluvium consisting of gravel, sand, silt, and clay; Upper Modesto (Qmu) typically unconsolidated and dense while the lower (Qml) typically unconsolidated to semi-consolidated and dense to very dense; very dense and/or semi-consolidated layers of the Modesto Formation may be identified as “hardpan.” Mapped along much of NEMDC, Arcade Creek, Dry Creek, and ARNL. • Riverbank Formation (Qru, Qrl): Mid-Pleistocene (estimated 130,000-450,000 years of age) alluvial fan consisting of gravel, sand, silt, and clay containing high-pedogenic silt and clay content and reddish hues reflective of its relative age; upper Riverbank Formation (Qru) typically semi-consolidated to consolidated while the lower (Qrl) typically consolidated and very dense; the very dense and/or consolidated layers of this formation locally referred to as “hardpan.” Mapped along significant portions of NEMDC, Dry Creek, and ARNL. • Turlock Lake Formation (Qtl): Early Pleistocene (estimated 450,000-600,000 years of age) alluvial fan consisting of well consolidated sand with some silt and minor gravel. Mapped along ARNL.

2.2.2 Generalized Near Surface Stratigraphy
Near surface stratigraphy (approximately upper 100 feet) was based on review and interpretation of geology publications, historical aerial photographs, current and historical topography, and existing subsurface data. The following provides a generalized stratigraphic description beginning from the bottom of the section along the study area levees.
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The Early Pleistocene Turlock Lake Formation underlies the study area levees at depth. The Turlock Lake Formation is an alluvial fan deposit mapped as exposed at the surface generally to the east of Watt Avenue where it is topographically higher than the Riverbank Formation. The Turlock Lake Formation generally consists of weathered sands with some gravels and silts.

The Pleistocene Riverbank Formation overlies the Turlock Lake Formation. Generally, the Riverbank Formation is an alluvial fan deposit mapped as exposed at the surface generally west of Watt Avenue and laterally continuous across the study area. The Riverbank Formation was gradually incised by historical and active streams to create current day conditions. The Riverbank Formation consists of predominately stiff to indurated fine-grained soils with localized channels of sands and gravels.

The Late Pleistocene Modesto Formation overlies the Riverbank Formation and is generally local to the active and historical streams and American River within the study area. The Modesto Formation varies in thickness extending to approximately 30 feet and consists of a wide range of materials including soft to indurated fine-grained soils as well as gravels and cobbles along the American River. Additionally, this unit has been significantly eroded and is laterally discontinuous.

Holocene and Recent fluvial deposits overlay the Riverbank and Modesto Formations along the study area streams and American River. The areas are generally blanketed by fine-grained soils indicative of lower energy overbank and basin deposits. The fine-grained soils are dissected by channel and crevasse deposits generally consisting of soils with higher percentage of sand.

The study area levees were constructed on top of the native soils in the mid-1900’s generally using nonmodern-day conventional construction methods and testing. The exception is the Arcade Creek north levee, the NEMDC east levee north of Arcade Creek, and DCSL, which were constructed in the mid-1950s using USACE levee construction methods, and the DCNL, which was constructed in 1996, using modern compaction and testing methods. The levee embankments generally consist of silty and clayey sands.

SAFCA and USACE have constructed improvements to the levees to strengthen them over time.

2.3 SEISMOTECTONIC SETTING
The project is located in the Western United States (WUS) in the transform plate boundary region between the Pacific Plate (transitioning northwest) and the North American Plate. The site lies within the Sierra Nevada-Great Valley block (a.k.a., the Sierra Nevada microplate, or SNGV) which generally is thought to act as an independent block that has ‘tilted’ westward. The SNGV block is bounded on its 24001006.001A/SAC24R164096_R1 Page 13 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
eastern edge by a zone of faults known as the Walker Lane Belt, beyond which is the crustal extensional region of the Northern Basin and Range. Further afield in the northwestern portion of the state and extending northward to the pacific northwest, the Juan de Fuca plate is currently subducting below the North American plate in a region known as the Cascadia Subduction Zone (Humphreys and Coblentz, 2007; Unruh and Humphrey, 2003, 2017).

Regional stress buildup due to the northwestern movement of the Pacific Plate is primarily released through displacement along faults within the San Andreas fault system (e.g., San Andreas fault, Hayward fault, etc.) and to a lesser extent by displacements along faults within the Walker Lane Belt. Crustal extension of the Northern Basin and Range has led to the development of stress in the east-west direction and caused development of an extensive system of faults within the Northern Basin and Range (Fey and Humphreys, 2008; Field et al., 2013). These faults and other regional seismic sources are shown on Figures 3 and 4 of the GMPSM (Kleinfelder, 2023b) in Appendix B. 24001006.001A/SAC24R164096_R1 Page 14 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
3 GROUND MOTION HAZARD ANALYSIS
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3.1 SEISMIC HAZARD ANALYSIS
Kleinfelder performed a site-specific probabilistic seismic hazard analysis (PSHA) for three control points within the NAS analysis area as shown on Figure 1-1. A detailed description of the probabilistic seismic hazard analysis performed for this project is presented in the GMPSM (Kleinfelder, 2023a) in Appendix B.

To account for site effects and basin effects, the site parameters in Table 3.1 were evaluated. Because ground motions were evaluated at stiff soil condition, the Vs30 (average shear wave velocity in the upper 100 feet/30 meters) value was taken as 335 m/s. Z1.0 and Z2.5 were estimated utilizing the correlations developed for the NGA West 2 project, with justification per Peterson et al. 2019.

For the Ground Motion Models (GMMs), Kleinfelder used four of the Next Generation Attenuation (NGA) West 2 relationships including Abrahamson et al. (2014), Boore et al. (2014), Chiou and Youngs (2014), and Campbell and Bozorgnia (2014) with equal weights applied for all crustal faults (e.g. reverse, strike-slip, normal) included in the fault model. The Idriss (2014) model has not been used as it is not valid for the VS30 used in our study and also for the larger distances used in this study (e.g. more than 150 km). The far-field subduction events (e.g. from Cascadia megathrust) were modeled using the relationships of Atkinson and Macias (2009), Abrahamson et al. (2016), and Zhao et al. (2006) with equal weights applied, except that for slab events the Atkinson and Macias (2009) relationship was excluded.

Spectral acceleration values are obtained by averaging the individual hazard results. These GMMs provide ‘mean’ (RotD50) values of ground motions associated with magnitude, distance, site soil conditions, and mechanism of faulting.

Table 3.1
Seismic Hazard Analysis Site Parameters
Point ID Latitude Longitude VS30
(m/s)
Z1.0
(km)
Z2.5
(km)
Arcade Creek 38.6668 -121.4762
Confluence 38.5982 -121.5087 335 0.428 1.55
American River East 38.5921 -121.3344
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3.1.1 Seismic Analysis Results
Kleinfelder calculated the probabilistic geometric mean Peak Horizontal Acceleration (PHA) values and deaggregation results at three points around the NAS analysis area (see Figure 1-1). The PHA has a 200- year return period and is listed in Table 3.2 along with the corresponding PHA value estimated from the Seismic Hazard Map in the 2015 ULE American River and NEMDC East GERs (URS, 2015a and 2015c).

Table 3.2
Probabilistic Peak Horizontal Acceleration and Controlling Earthquake Magnitude Point ID
PHA (g) Deaggregation Results
(KLF, 2023) (URS,
2015) MW Distance (km)
Arcade Creek 0.13 0.139 6.8 72
Confluence 0.14 0.146 6.8 67
American River East 0.12 0.126 6.8 81
The new PHA values calculated for each NAS analysis control point corresponding have small differences from the 2015 ULE. However, the 2015 ULE performed liquefaction analyses used an earthquake magnitude of 6.5, and Kleinfelder’s deaggregation produced a magnitude of 6.8. Hence, Kleinfelder performed liquefaction analyses using the original PHA values and the larger 2023 KLF magnitude. The old PHA values were used in the evaluation as the new values are not significantly different from the old values and are slightly conservative.
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4 PREVIOUS EVALUATION
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4.1 SUMMARY
The 2015 URS Geotechnical Evaluation Reports for the NEMDC East and American River North study areas (URS, 2015a and 2015c) performed Seismic Vulnerability Evaluations in accordance with the requirements developed for ULE. SPT-based liquefaction analyses were performed to identify layers at risk for liquefaction and non-liquefiable layers. These results were used where applicable to perform post-seismic stability and deformation analyses and classify the seismic vulnerability of each levee segment.

4.1.1 General
Kleinfelder reviewed the 2015 URS Seismic Vulnerability Analyses for the NAS levee segments as part of the Phase 1 Screening Analysis. Segments with High Vulnerability classifications and segments noted as non-liquefiable were not required to receive further analysis. Any segments noted as having both Low or Medium Vulnerability and containing at least one liquefiable layer required further review, which is discussed in Section 5 CURRENT EVALUATION, and are shaded gray in Table 4.1.

Table 4.1
Phase 1 – Seismic Vulnerability Results Screening
Segment ID Station Start Station End 2015 URS
Vulnerability
Contains
Liquefiable Layer
Additional
Analysis Required
American River – North Bank
AR-7 3000+00 3016+00 Low No No
AR-8 3016+00 3044+48 High Yes No
AR-9 3044+48 3085+35 Low No No
AR-10 3085+35 3088+60 High Yes No
AR-11 3088+60 3102+85 Low No No
AR-12 3102+85 3167+50 Low Yes Yes
AR-13 3167+50 3306+00 High Yes No
AR-14 3306+00 3458+85 Low Yes Yes
AR-15 3458+85 3482+50 High Yes No
AR-16 3482+50 3582+79 Low No No
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Table 4.1 (cont.)
Phase 1 – Seismic Vulnerability Results Screening
Segment ID Station Start Station End 2015 URS
Vulnerability
Contains
Liquefiable Layer
Additional
Analysis Required
NEMDC East/North Area Streams
NMDE-1 2986+49 2995+91 Low No No
NMDE-2 2995+91 3011+65 Low Yes Yes
NMDE-3 3011+65 3192+23 Low Yes Yes
NMDE-4 4000+00 4110+34 Low No No
NMDE-5 5000+00 5112+43 Low No No
NMDE-6 6000+00 6106+66 Low No No
NMDE-7 6106+66 6167+62 Low No No
NMDE-8 7000+00 7085+57 Low No No

4.2 SEISMIC ANALYSIS WATER SURFACE ELEVATIONS
Per the Guidance Document (URS, 2015b), seismic vulnerability analyses were performed using the higher of the average summer or winter Water Surface Elevations (WSE) at each ULDC segment.

Kleinfelder assessed the applicability of the average WSEs used for the 2015 liquefaction calculations for the updated calculations. The California Department of Water Resources (DWR) provides a database of groundwater well measurements across the Sacramento Valley. For the updated calculations, data from wells located near a ULDC segment were evaluated for further analysis. Upon review of the available information, the mean winter and summer groundwater elevations were lower than those used for the seismic analyses in 2015. Generally, mean groundwater elevations from the past ten years were lower than those used in the liquefaction analyses in the same area by approximately 10 feet, possibly due to droughts and other seasonal factors. Therefore, it was decided to continue using the same WSEs from 2015 study because they are higher in elevation and would provide conservative results for liquefaction. 24001006.001A/SAC24R164096_R1 Page 18 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
5 CURRENT EVALUATION
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5.1 SEISMIC EVALUATION SEGMENT SELECTION
Segments AR-12, AR-14, NMDE-2, and NMDE-3 were categorized by the 2015 ULE GERs as having low seismic vulnerability and layers with the potential for liquefaction. These segments met the criteria for a targeted evaluation using the updated deaggregation results from Kleinfelder’s GMHA.

5.1.1 Liquefaction Analysis of ULDC Segments
The 2015 URS evaluations produced SPT-Based Liquefaction Analysis Excel spreadsheets for multiple borings corresponding to the ULDC segments. These analyses for the selected NASL segments were recalculated using the updated GMHA deaggregation magnitude of 6.8. The spreadsheet calculations are included in Appendix D: Updated SPT-Based Liquefaction Calculations for Targeted Segments.

The borings for the targeted evaluation segments are listed in Table 5.1.1. The Factors of Safety (FOS) of some potentially liquefiable layers decreased from above to below 1.25 (“Non-Liquefiable” to “Less Likely Liquefiable”), and some decreased from above to below 1.0 (“Less Likely Liquefiable” to “Likely Liquefiable”). Table 5.1.1 notes borings where at least one layer changed in one of these ways; Table

5.1.2 describes the affected layers and their new Factors of Safety against liquefaction.

Table 5.1.1
Liquefaction Layer Changes for Targeted Segments
Segment
ID
Station
Start
Station
End
Liquefaction Analysis Boring
(Station)
Liquefiable Layer
Classification Change
American River – North Bank
AR-12 3102+85 3167+50
2F-97-04 (3106+13) No
2F-99-04A (3151+12) Yes
2F-96-10 (3126+49) Yes
AR-14 3306+00 3458+85
2F-97-06 (3307+50) Yes
2F-97-14 (3360+71) No
2F-99-09A (3397+21) No
2F-99-11A (3449+67) Yes
WCNBAR_003B (3306+35) No
24001006.001A/SAC24R164096_R1 Page 19 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Table 5.1.1 (cont.)
Liquefaction Layer Changes for Targeted Segments
Segment
ID
Station
Start
Station
End
Liquefaction Analysis Boring
(Station)
Liquefiable Layer
Classification Change
NEMDC East/North Area Streams
NMDE-2 2995+91 3011+65 K95_BE20 (3008+90) No
NMDE-3 3011+65 3192+23
K02-B3 (3038+75) Yes
WRARFC_002B (3051+36) No
WRARFC_045B (3080+63) No
WRARFC_031B (3167+60) No
Because the liquefiable layer classifications did not change for the boring within Segment NMDE-2, it remains classified as Low Vulnerability and additional analysis was not necessary.

Table 5.1.2
Liquefaction Factor of Safety Changes for Targeted Segments1 Segment
ID
Boring
(Station)
Elevation
(feet)
Layer
Thickness
(feet)
Liquefaction FOS
(2015, Mw = 6.5)
Liquefaction FOS
(2023, Mw = 6.8)
AR-12
2F-96-10
(3126+49)

15.2 3.5 1.36 1.23

11.7 3.5 1.32 1.19
2F-99-04A
(3151+12)

13.0 3.0 1.33 1.20
AR-14
2F-97-06
(3307+50)

19.7 5.0 1.10 0.99

14.7 5.0 1.06 0.96
2F-99-11A
(3449+67)

2.9 5.0 1.03 0.94
NMDE-3
K02-B3
(3038+75) 3.5 5.0 1.26 1.14

1. Yellow: FOS indicates layer is “Less Likely Liquefiable.” Red: FOS indicates layer is “Likely Liquefiable.”
Vertical settlement calculations are not required because the liquefiable layers do not exceed 20 feet in thickness (URS, 2015b).
24001006.001A/SAC24R164096_R1 Page 20 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

5.2 VULNERABILITY CLASSIFICATIONS FOR TARGETED SEGMENTS The American River and NEMDC East GER Reports (URS, 2015a; URS, 2015c) include post-seismic slope stability models for targeted segments AR-12 and AR-14. These FOS against stability failure using global and block type analysis methods. No post-seismic stability model was produced for Segment NMDE-3.

The 2015 URS results for stability FOS are displayed in Table 5.2.1.

Table 5.2.1
2015 URS Post-Seismic Stability Analysis Factors of Safety for Targeted Segments Segment
ID
Analysis
Station
Landside
Global FOS
Landside
Block FOS
Waterside
Global
FOS
Waterside
Block FOS
2015 Seismic
Vulnerability
AR-12 3109+57 2.61 2.56 2.65 2.58 Low
AR-14 3306+10 6.03 5.47 4.63 4.43 Low
NMDE-3 No post seismic stability analysis performed in 2015 Low

5.2.1 Segment AR-12
The post-seismic cross section for Segment AR-12, Station 3109+57 analyzed in the American River GER (URS, 2015a) features a 7-foot Less Likely Liquefiable layer between approximate elevations 16.7 feet and 9.7 feet. The three Less Likely Liquefiable layers identified in the updated liquefaction calculations are found at elevations within this range; based on the thicknesses of these layers, the Less Likely Liquefiable layer for AR-12 would be updated to approximately 10 feet thick. However, this is not expected to significantly lower the segment’s post-seismic stability FOS, which exceeds 2.5 as shown in Table 5.2.1. Because the liquefaction calculations showed no layers for the segment become Likely Liquefiable, the cross-sectional material properties did not need to be updated.

5.2.2 Segment AR-14
The post-seismic cross section for Segment AR-14, Station 3306+10 analyzed in the American River GER (URS, 2015a) features an 11-foot Less Likely Liquefiable SP-SM layer between approximate elevations

21.9 feet and 10.9 feet. The stratigraphy, piezometric surface, and material properties of this cross section were selected based on the lab testing and liquefaction analysis results for Boring 2F-97-06.

The layer’s post-seismic shear strength was originally calculated by reducing the static drained strengths by 30%. However, because the updated liquefaction calculations classify the 11-foot layer as Likely Liquefiable, the post-seismic cross section’s stability calculations are outdated. Therefore, the cross section for Segment AR-14 was updated using residual undrained shear strengths for the Likely Liquefiable layer. The stability analysis is included as Appendix E.

5.2.2.1 Segment AR-14 Stability Analysis – Material Properties First, the residual undrained strength of the Likely Liquefiable layer was estimated. The updated liquefaction analysis produces (N1)60 value of 9 for the Likely Liquefiable SP-SM layer. After the fines/classification correction, the (N1)60-cs value becomes 10. Using the Seed-Harder Plot for Residual Strength and the procedure described in Section 6.8.2.1 in the ULE Guidance Document (2015), the residual undrained strength for the Likely Liquefiable layer was estimated as 235psf.

Additionally, the cross-sectional material properties were checked and updated using site-specific values. Effective friction angle and cohesion values from the 2015 URS Segment 14 Transverse Cross Section were used for the SM and GP layers. Per Section 5.8 of the Guidance Document (URS, 2015b), site-specific field and laboratory results were used to select material properties not listed in the 2015 URS slope stability analysis. The SPT-based liquefaction analysis for Boring ID 2F-97-06 was used to estimate unit weights for the soil layers. The slurry wall unit weight was selected as 100 pounds per cubic foot (pcf) from the American River GER (URS, 2015a) material properties for the Reach A existing soil-cement-bentonite wall (GER Table B1-A-1). This table was also used to select the undrained friction angle and cohesion values for the CL layers.

Material properties are listed in Table 5.2.2. Refer to Appendix E for the calculation package and sources for the stratigraphy and material properties.
24001006.001A/SAC24R164096_R1 Page 22 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Table 5.2.2
Material Properties for Segment AR-14 Post-Seismic Stability Analysis Material Unit Weight
(pcf) Ф’ (dgs) C’ (psf)
1 – SM 125 32 0
2 – SM 120 32 0
3 – SP-SM (Liquefiable) 125 0
235 (residual undrained
strength)
4 – GP 130 35 0
5 – CL 125 7 960
6 – CL Cap 125 7 960
7 – Cutoff Wall 100 0 500

5.2.2.2 Segment AR-14 Stability Analysis – Slope Stability The cross section at Station 3306+10 was constructed in SLOPE/W (GeoStudio 2023.1.2) with the Seismic Analysis WSE located at Elevation 21.9 feet (NAVD88 Datum). The FOS against slope stability failure was calculated using entry and exit slip surfaces (circular) and block specified with optimized critical slip surfaces (wedge) for the levee landside and waterside. Results are attached in Appendix E:

Post-Seismic Slope Stability Analysis for Segment AR-14. The post-seismic slope stability Factors of Safety are summarized in Table 5.2.3.

Table 5.2.3
Segment AR-14 Post-Seismic Slope Stability Factors of Safety Segment
ID
Analysis
Station
Landside
Global FOS
Landside
Block FOS
Waterside
Global
FOS
Waterside
Block FOS FOS Required
AR-14 3306+10 3.33 2.69 2.32 2.05 > 1.3
All Factors of Safety against slope stability failure are greater than 1.3. Seismic Analysis Segment AR-14 remains classified as Low Vulnerability.
24001006.001A/SAC24R164096_R1 Page 23 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

5.2.3 Segment NMDE-3
No post-seismic cross sections or stability calculations were made for Segment NMDE-3 in the NEMDC East GER (URS, 2015c) analysis because the original analysis did not identify any liquefiable layers.

However, a post-seismic analysis was performed at Station 3009+00 for Segment NMDE-2 because it contained a 12-foot-thick Likely Liquefiable layer between approximate elevations 13.5 feet and 1.5 feet. The post-seismic stability results for Segment NMDE-2 are summarized in Table 5.2.4 below:

Table 5.2.4
2015 URS Post-Seismic Stability Analysis Factors of Safety for Segment NMDE-2 Segment
ID
Analysis
Station
Landside
Global FOS
Landside
Block FOS
Waterside
Global
FOS
Waterside
Block FOS
2015 Seismic
Vulnerability
NMDE-2 3009+00 1.53 1.35 1.50 1.34 Low
Since the minimum post-seismic FOS is above 1.3, Segment NMDE-2 is classified as having Low Vulnerability. As shown in Table 5.1.2, Segment NMDE-3 features one Less Likely Liquefiable layer of thickness 5 feet. As such, it is assumed Segment NMDE-3 is comparatively less vulnerable than NMDE-2; therefore, since Segment NMDE-2 is classified as Low Vulnerability, Segment NMDE-3 remains classified as Low Vulnerability.
24001006.001A/SAC24R164096_R1 Page 24 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
6 SEISMIC PERFORMANCE
_____________________________________________________________________

6.1 SUMMARY
Four Low Vulnerability segments in the North Area Streams levee region were selected for further analysis using the results of Kleinfelder’s GMHA. Kleinfelder performed liquefaction analyses using updated magnitude Mw = 6.8 and identified segments with additional layers that became less likely or likely liquefiable. Based on further investigation into each segment, Kleinfelder concluded that the four segments remain Low Vulnerability regarding seismic hazards.

The seismic vulnerability for the North Area Streams levees remains the same as the 2015 URS analysis.

Segments and their seismic vulnerability classifications are listed in Table 6.1.

Table 6.1
Seismic Vulnerability Classifications for North Area Streams Levees Segment ID Station Start Station End 2015 Seismic
Vulnerability
2023 Seismic
Vulnerability
American River - North Bank
AR-7 3000+00 3016+00 Low Low
AR-8 3016+00 3044+48 High High
AR-9 3044+48 3085+35 Low Low
AR-10 3085+35 3088+60 High High
AR-11 3088+60 3102+85 Low Low
AR-12 3102+85 3167+50 Low Low
AR-13 3167+50 3306+00 High High
AR-14 3306+00 3458+85 Low Low
AR-15 3458+85 3482+50 High High
AR-16 3482+50 3582+79 Low Low
NEMDC East/North Area Streams
NMDE-1 2986+49 2995+91 Low Low
NMDE-2 2995+91 3011+65 Low Low
NMDE-3 3011+65 3192+23 Low Low
NMDE-4 4000+00 4110+34 Low Low
NMDE-5 5000+00 5112+43 Low Low
NMDE-6 6000+00 6106+66 Low Low
NMDE-7 6106+66 6167+62 Low Low
NMDE-8 7000+00 7085+57 Low Low
24001006.001A/SAC24R164096_R1 Page 25 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
7 LIMITATIONS
___________________________________________________________________________________ Information contained in this data report is based on our field observations, subsurface explorations completed by Kleinfelder and others, laboratory tests completed by Kleinfelder and others, and our present knowledge of the existing levee conditions. The conclusions and opinions contained in this report are also based on the assumption that information provided by the Client and/or that is referenced in this report is accurate and correct and can be relied upon. It is possible that soil conditions, including groundwater levels, could vary between or beyond the points explored.

The information, including graphic representations attached to this report, have been compiled from a variety of sources as referenced herein and are 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 the information presented in this data report. These documents are not intended for use as land survey products, nor are they designed or intended as construction design documents. The use or misuse of the information contained on these graphic representations is at the sole risk of the party using or misusing the information.

We have prepared this data report in substantial accordance with the generally accepted geotechnical engineering practice as it exists in the site area at the time of our study. No warranty, express or implied, is provided. 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 the report, 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 liability resulting from the use of this report by any unauthorized party. 24001006.001A/SAC24R164096_R1 Page 26 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
8 REFERENCES
___________________________________________________________________________________ Abrahamson, N., Gregor, N., Addo, K. (2016). BC Hydro Ground Motion Prediction Equations for Subduction Earthquakes. Earthquake Spectra, Volume 32, Issue 1, pp. 23-44.

Abrahamson, N.A., Silva, W.J., and Kamai, R. (2014). “Summary of the ASK14 Ground Motion Relation for Active Crustal Regions.” Earthquake Spectra, Vol. 30, No. 3, pp. 1025-1056.

Atkinson, G.M., and Macias, M. (2009). Predicted Ground Motions for Great Interface Earthquakes in the Cascadia Subduction Zone. Bulletin of the Seismological Society of America, V. 99, No. 3, pp. 1552-1578.

Boore, D.M., Stewart, J.P., Seyhan, E., and Atkinson, G. (2014). “NGA-West2 Equations for Predicting PGA, PGV, and 5% damped PSA for Shallow Crustal Earthquakes.” Earthquake Spectra, Vol. 30, No. 3, pp. 1057-1086.

Campbell, K.W., and Bozorgnia, Y. (2014). “NGA-West2 Ground Motion Model for the Average Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra.” Earthquake Spectra, Vol. 30, No. 3, pp. 1087-1116.

Cetin et al. (2004). “Standard Penetration Test-Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Potential,” Journal of Geotechnical and Geoenvironmental Engineering, Volume 130, Issue 12, ASCE, dated December 2004.

Chiou, B.S., and Youngs, R.R. (2014). “Update for the Chiou and Youngs NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra.” Earthquake Spectra, Vol. 30, No. 3, pp. 1117-1154.

Fey, N., Humphreys, E., 2008, Forces Acting on the Sierra Nevada Block and Implications for the Strength of the San Andreas Fault System and the Dynamics of Continental Deformation in the Western United States. Journal of Geophysical Research, Vol. 113, B 12415.

Field, E.H., Biasi, G.P., Bird, P., Dawson, T.E., Felzer, K.R., Jackson, D.D., Johnson, K.M., Jordan, T.H., Madden, C., Michael, A.J., Milner, K.R., Page, M.T., Parsons, T., Powers, P.M., Shaw, B.E., Thatcher, W.R., Weldon, R.J., II, and Zeng, Y. (2013). The Uniform California Earthquake Rupture Forecast, Version 3 (UCERF 3), USGS Open File Report 2013-1165, CGS Special Report 228, Southern California Earthquake Center Publication 1792, http://pubs.usgs.gov/of/2013/1165/. 24001006.001A/SAC24R164096_R1 Page 27 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Fugro William Lettis & Associates, Inc. (2011). “Technical Memorandum: Surficial Geologic Map and Geomorphic Assessment of the Natomas East Main Drainage Canal, East (NEMDC East) Study Area, Sacramento County, California,” dated February 16, 2011.

Fugro William Lettis Associates (FWLA 2008). “Surficial Geologic Map of the American River Study Area.” Scale 1:20,000. Dated 2008.

Fugro William Lettis Associates (FWLA 2011). “Surficial Geologic Map of the NEMDC East Study Area.” Scale 1:20,000. Dated 2011.

Gutierrez, C. I. (2011). “Preliminary Geologic Map of the Sacramento 30’ x 60’ Quadrangle, California,” California Geological Survey, Preliminary Geologic Maps PGM-11-06 (1:100,000 scale).

Hatanaka, M., and Uchida, A. (1996). “Empirical Correlation Between Penetration Resistance and Internal Friction Angle of Sandy Soils,” Soils and Foundations, ASCE, Vol. 36, No. 4, pp. 1-9.

Helley, E. J., and Harwood, D. S. (1985). “Geologic Map of the Late Cenozoic Deposits of the Sacramento Valley and Northern Sierran Foothills, California,” U. S. Geological Survey Miscellaneous Field Studies Map MF-1790.

Humphreys, E., and Coblentz, D., 2007, North American Dynamics and Western U.S. Tectonics. American Geophysical Union, Reviews of Geophysics, 45, RG3001.

Idriss, I.M. (2014). “An NGA-West2 Empirical Model for Estimating the Horizontal Spectral Values Generated by Shallow Crustal Earthquakes.” Earthquake Spectra, Vol. 30, No. 3, pp. 1155-1177.

Jennings, C.W., Strand, R.G., and Rogers, T.H. (1977), Geologic Map of California: California Division of Mines and Geology Geologic Data Map Series Map No. 2 (1:750,000 scale).

Kleinfelder (2016a). “Problem Identification Report, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee), Sacramento County, California,” dated April 29, 2016.

Kleinfelder (2016b). “ULDC Geotechnical Results Summary, North Area Streams, SAFCA FEMA Levee Accreditation (North Area Streams, American River, Sacramento River Downstream of American River, and Beach Lake Levee), Sacramento County, California,” dated April 29, 2016. 24001006.001A/SAC24R164096_R1 Page 28 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
Kleinfelder (2023a). “Seismic Evaluation Technical Approach Memorandum, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento and Sutter Counties, California,” dated September 29, 2023.

Kleinfelder (2023b). “Seismic Evaluation Ground Motion Parameter Selection Memorandum, ULDC & FEMA Levee Certification Project, Sacramento Area Flood Control Agency Levee Systems, Sacramento and Sutter Counties, California,” dated October 13, 2023.

Unruh, J., and Humphrey, J., 2017, Seismogenic Deformation Between the Sierran Microplate and Oregon Coast Block, California, USA. The Geological Society of America v. 45, no. 5, pp. 415-418.

Unruh, J., Humphrey, J., and Barron, A., 2003, Transtensional Model for the Sierra Nevada Frontal Fault System, Eastern California. Geology v. 31, no. 3, pp. 327 – 330.

URS Greiner (2000). “Plans for American River Watershed Project (Common Features), California Left (South) Bank Levee Straightening, Contract 2,” dated January 18, 2000.

URS (2009). “Phase 1 Geotechnical Data Report (P1GDR), Natomas East Main Drainage Canal (NEMDC) Study Area, Urban Levee Geotechnical Evaluations Program, Contract 4600007418,” dated March 2009 (Issue date: 04-2009).

URS (2011). “Supplemental Geotechnical Data Report (SGDR), Natomas East Main Drainage Canal (NEMDC) Study Area, Urban Levee Geotechnical Evaluations Program, Contract 4600007418,” dated November 2011 (Issue date: 11-2011).

URS (2011). “Supplemental Geotechnical Data Report (SGDR), American River Study Area, Urban Levee Geotechnical Evaluations Program, Contract 4600007418,” dated June 2010 (Issue date: 06- 2010).

URS (2015a). “ULE Geotechnical Evaluation Report (GER) Volume 1 and 2, American River Study Area, Urban Levee Evaluations Project, Contract 4600008101,” dated January 2015 (Issue date: 01- 2015).

URS (2015b). “Guidance Document for Geotechnical Analyses, Urban Levee Geotechnical Evaluations Program, Contract 4600008101,” dated April 2015.

URS (2015c). “ULE Geotechnical Evaluation Report Volume 2, Remedial Alternatives, NEMDC East Study Area, Urban Levee Evaluations Project, Contract 4600008101,” dated April 2015 (Issue date: 04- 2015).
24001006.001A/SAC24R164096_R1 Page 29 of 29 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)
United States Army Corps of Engineers (USACE) (1990). “Settlement Analysis, EM 1110-1-1904,” dated 30 September 1990.

USACE (2001). “Geotechnical Investigations, EM 1110-1-1804”, dated 1 January 2001.

USACE (2015). “Geotechnical Office Report, American River Watershed Common Features Project General Reevaluation Report,” dated October 2013.

USACE (2016). ER 1110-2-1806 Earthquake Design and Evaluation for Civil Works Projects.

Wagner, D.L., Jennings, C.W., Bedrossian, T.L., and Bortugno, E.J. (1981). Geologic Map of the Sacramento Quadrangle, California, 1:250,000 scale, California Department of Conservation, Geological Survey, Regional Geologic Map Series, Map No. 1A.

Zhao et al. (2006). Attenuation Relations of Strong Ground Motion in Japan using Site Classification Based on Predominant Period. Bulletin of the Seismological Society of America, V. 96, No. 3, pp. 898-913.
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AR-11
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AR-9 AR-12
NMDE-8
AR-16
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6167+62
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2995+91 3011+65
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SITE MAP
PROJECT:

FILE NAME:

FIGURE
1-1
DRAWN:

CHECKED BY:

DRAWN BY:
24001006.001A
FEB 2024
R.HOCHSTATTER
A.LEONARD
F1-1_NAS_SiteMap-V2.mxd
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!( Analysis Control Point
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Locations are Approximate £
Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri
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Source: Esri, Maxar, Earthstar Geographics, and the GIS User !
Project Location
^

NORTH AREA STREAMS/

AMERICAN RIVER NORTH LEVEES

SEISMIC PERFORMANCE SUMMARY REPORT

SAFCA LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
AR-13 Seismic Segment
FIGURE
DRAWN BY:

PROJECT NO.

CHECKED BY:

REVISED:

DATE:

Dry Creek North
Arcade Creek South
Arcade Creek North
Dry Creek South
NEMDC East
American River North Bank

REGIONAL GEOLOGY
PROJECT:

FILE NAME:

FIGURE
2-1
DRAWN:

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OCT 2023
M. RYAN
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F2-1_NAS_Geology_AL_V2.mxd
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Kilometers
Locations are Approximate £

NORTH AREA STREAMS/

AMERICAN RIVER NORTH LEVEES

SEISMIC PERFORMANCE SUMMARY REPORT

SAFCA LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA

NORTH AREA STREAMS LEVEES

GEOLOGY MAP
PROJECT:

FILE NAME:

FIGURE
2-2
DRAWN:

CHECKED BY:

DRAWN BY:
24001006.001A
OCT 2023
M. RYAN
A.LEONARD
SAFECA_working.mxd
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NORTH AREA STREAMS/

AMERICAN RIVER NORTH LEVEES

SEISMIC PERFORMANCE SUMMARY REPORT

SAFCA LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA

AMERICAN RIVER NORTH LEVEE

GEOLOGY MAP
PROJECT:

FILE NAME:

FIGURE
2-3
DRAWN:

CHECKED BY:

NORTH AREA STREAMS/

AMERICAN RIVER NORTH LEVEES

SEISMIC PERFORMANCE SUMMARY REPORT

SAFCA LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
24001006.001A/SAC24R164096_R1 Page A-1 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

APPENDIX A

SEISMIC TECHNICAL APPROACH MEMORANDUM
_____________________________________________________________________ 24001006.001A/SAC24M163970 Page 1 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

SEISMIC EVALUATIONTECHNICAL APPROACH MEMORANDUM
DATE: February 8, 2024
TO: Mr. Pete Ghelfi, PE
Director of Engineering
Sacramento Area Flood Control Agency
1325 J Street, Suite 1700
Sacramento, CA 95814
FROM: Ryan Hochstatter, EIT
Zia Zafir, PhD, PE, GE
SUBJECT: Seismic Evaluation Technical Approach Memorandum ULDC & FEMA Levee Certification Project
Sacramento Area Flood Control Agency Levee Systems
Sacramento and Sutter Counties, California
___________________________________________________________________________________ 1 INTRODUCTION
Kleinfelder has been tasked by the Sacramento Area Flood Control Agency (SAFCA) with evaluating the seismic vulnerability of the Sacramento area levees located in Sacramento and Sutter Counties, California as shown on Attachment 1. This technical approach memorandum presents the methodology for the seismic evaluation consistent with the Urban Levee Design Criteria (ULDC) (DWR, May 2012) and the Urban Levee Evaluations Project Guidance Document for Geotechnical Analysis (DWR Guidance Document) (DWR and URS, 2015).

This memorandum has been prepared consistent with the requirements of the approved scope of work for the subject project outlined in Kleinfelder’s proposal dated May 5, 2023. 2 PURPOSE
SAFCA is working with a team of consultants to obtain ULDC and Federal Emergency Management Agency (FEMA) certifications for the Sacramento area levees. The purpose of this document is to establish a seismic vulnerability evaluation methodology that conforms to ULDC. Methodology will generally follow seismic vulnerability guidelines for intermittently-loaded levees as described in the DWR Guidance Document (DWR and URS, 2015). The results of the seismic vulnerability evaluation will be used to evaluate the seismic vulnerability for FEMA certification.

The levees will be organized by selection of “sections” instead of reaches due to the variable nature of subsurface conditions under levees. Sections may overlap multiple reaches or reaches may be subdivided into multiple sections. Note that for sections encompassing or divided by roadway overcrossings, the overcrossings will be simplified to their centerlines, and additional improvements to the levee for overcrossing abutments will be neglected. 24001006.001A/SAC24M163970 Page 2 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 3 PROJECT FEATURES
Attachment 1, Seismic Planning Services Responsibility Map, shows the following levee systems and their associated component levees. The levee systems are summarized in Table 1 below.

Table 1: Levee Systems and Component Levees
Levee System Reach
1 - Dry Creek Dry Creek North Levee
2 - Robla-Arcade
Dry Creek South / Robla Levee
Natomas East Main Drainage Canal (NEMDC) East Levee - Robla to Arcade Creek Arcade Creek North Levee
3 - American North
Arcade Creek South Levee
NEMDC East Levee - Arcade Creek to American River
American River North Levee
4 - American South
American River South Levee
Sacramento River East Levee (SREL) - American River to NBLL North Beach Lake Levee
5 - Natomas Basin
Natomas Cross Canal South Levee (NCC)
SREL - NCC to Powerline Road
SREL - Powerline Road to American River
American River North Levee - Sacramento River to NEMDC
NEMDC West Levee
Pleasant Grove Creek Canal (PGCC) West Levee
4 GOVERNING STANDARDS
Methodology for conducting seismic vulnerability evaluation of levees is governed by design criteria developed by the California Department of Water Resources (DWR). Relevant publications that will be the primary source for Kleinfelder’s analysis includes:
• Urban Levee Design Criteria (ULDC, 2012) “Section 7.7 – Seismic Vulnerability” • Urban Levee Evaluations Project Guidance Document for Geotechnical Analysis (ULE, 2015), DWR and URS, “Section 6.0 – Seismic Analysis” - included as Attachment 3 Additionally, ground motion parameter development for evaluations is governed by applicable US Army Corps of Engineer’s Regulations and Manuals (ER & EM). Design guidance applicable to the seismic evaluation includes:
• Engineering Manual (EM) 1110-2-1913 (April 2000, USACE) “Design and Construction of Levees” 24001006.001A/SAC24M163970 Page 3 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 • Engineer Regulation (ER) 1110-2-1806 (May 2016, USACE) “Earthquake Design and Evaluation for Civil Works Projects”
• Engineering and Design Technical Letter (ETL) 1110-2-580 (March 2013, USACE) “Guidelines for Seismic Evaluation of Levees”
5 SESIMIC VULNERABILITY EVALUATION WORKFLOW
An overview of the seismic vulnerability evaluation workflow is shown on Attachment 2. The seismic vulnerability evaluation workflow was adapted from the DWR seismic vulnerability evaluation as a part of the DWR ULDC Guidance Document included as Attachment 3. Three stages of evaluation are identified as:

1. Preliminary Work

2. Phase 1: Screening Review of Existing Analysis

3. Phase 2: Targeted Evaluation
Each stage is discussed in greater detail in the sections below.

5.1 Preliminary Work and Methodology for Developing New Peak Ground Accelerations The existing geotechnical analysis and subsurface data will be reviewed to identify the seismic segments.

During this process, any data gaps will be identified, and an updated peak ground acceleration (PGA) and earthquake magnitude will be established.

5.1.1 Existing Ground Motion Data
Previous development of ground motion parameters in the area was performed by URS in 2007 as part of the Delta Risk Management Strategy (DRMS), which was updated and expanded on in 2012 by URS as part of the Department of Water Resources’ (DWR) Urban Levee Evaluation (ULE) project. A 200-year return period seismic hazard map was developed for the ULE area, which encompasses the ULDC area.

The probabilistic seismic hazard analysis performed for the ULE area was based on the UCERF2 seismic source characterization. The ground motion parameters developed by URS consisted of peak horizontal acceleration for soil/rock condition at a depth of 300 feet below the ground surface. In addition, associated earthquake magnitude was also estimated.

For this project the source characterization by others will be reviewed, where high-quality peer reviewed seismic source models are available. This will include studies performed by the United States Geological Survey applicable to the project region (e.g. Petersen et al. 2014, 2019), statewide studies performed as part of the third Uniform California Earthquake Rupture Forecast (UCERF3 - Field et al., 2013). It is expected the UCERF3 characterization will be primarily used for this project due to its wide adoption in other work and for consistency with the deprecated UCERF2 model used in previous work by URS. Additionally, Petersen et al. (2014, 2019) models will be used for far-field seismic sources outside of California (e.g. Cascadia, etc.)
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Analysis performed by URS in 2012 for ULE identified several potential seismic sources in the area that were not included in the UCERF2 model (i.e. Northern Midland fault zone). The UCERF3 model will be evaluated for inclusion of these sources.

Following evaluation of existing design ground motion data, segments of levee with either non-existent or out-of-date seismic data will be analyzed according to procedures described below.

5.1.2 Probabilistic Seismic Hazard Analysis (PSHA)
The PSHA approach that will be used to estimate the ground motion parameters (typically peak ground and spectral ground accelerations) is generally consistent with requirements of ULDC, with some modifications in implementation based on current standards of practice for probabilistic evaluations in California (e.g. “Grand Inversion” approach). The probabilistic approach is used in place of a deterministic approach as permitted by ER 1110-2-1806 §7d.

A site-specific PSHA is a useful tool in the evaluation of the potential ground motion hazard at a site. The model generally includes a representative seismic source model (such as geometry, style of faulting, magnitude, etc.), appropriate recurrence relationships, and appropriate ground motion models (aka. attenuation relationships). Modifications to the standard approach can also incorporate site-specific evaluation of site effects such as amplification. The model can be used to quantify the potential for strong ground shaking at a site. The hazard results are typically interpreted at a given earthquake return period to provide an equal or uniform hazard spectrum (UHS) for use in design.

The PSHA uses a logic tree approach to account for epistemic uncertainty in the model, with aleatoric variability accounted for in the uncertainty associated with various models (e.g. GMM’s). The logic tree is developed to account for uncertainties in the source models, ground motion models, and other items impacting the results. Important source characteristics include slip rates and fault lengths, magnitude and recurrence intervals of potential seismic events, distance from the site to the causative source, and other parameters. The effects of site soil conditions, and other considerations such as basin effects, can be accounted for using ground motion models (GMMs).

The theory behind the probabilistic approach to seismic risk analysis has been developed over many years (Cornell, 1968, 1971; Merz and Cornell, 1973; SSHAC, 1997), and is based on the "total probability theorem". Generally, this work uses an assumption that earthquakes are events that are independent of time and space from one another (e.g. time independent models). According to this approach, the probability of exceedance PE(z) at a given level of ground motion, z, at the site within a specified time period, t, is related to the annual frequency of exceedance v(z) by:

𝑃𝐸
(𝑧) = 1 −𝑒𝑥𝑝 𝑒𝑥𝑝 (−𝑣(𝑧) ∗ 𝑡)
Different probabilities of exceedance may be selected, depending on the level of performance required.

The return period is essentially equivalent to the reciprocal of v(z).

The PSHA is conducted using three generalized steps that include the following. 24001006.001A/SAC24M163970 Page 5 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

1. Development of an appropriate seismic source model including source characterization, development of recurrence relationships, and appropriately capturing uncertainty

2. Selection of appropriate ground motion models (and site amplification models, if appropriate)

5.1.3 Seismic Source Model
The seismic source model for a site contains all information required to characterize potential seismic sources for use in evaluation of ground motion parameters. The source model typically includes information on the geometry (e.g. length, dip, depth, etc.), style of faulting, magnitude, and recurrence relationships for all potentially active seismic sources within a distance capable of significantly impacting a site. The source model used for this work is discussed below.

5.1.4 ‘Grand Inversion’ and Recurrence Rates
The earthquake recurrence rates used in the source model will be adopted as developed by the UCERF3 project, as implemented by Petersen et al. (2019) using the branch-averaged solutions of the ‘grand inversion’. This is a departure from the older standard of practice documented in EM 1110-2-6053 and Draft EM 1110-2-6000, which solves for the entire system of faults within California simultaneously.

The ‘grand inversion’ scheme developed by the UCERF3 project team, the results of which will be adopted in this work, ‘solved’ the on-fault and off-fault recurrence rates at a system level using a set of defined constraints including the spatial probability density of off-fault seismicity, slip rate balancing, paleoseismic even rate matching, fault smoothness constraint, regional magnitude frequency distribution constraints, and fault section specific magnitude frequency distribution constraints. In simple terms the ‘grand inversion’ solves for three things: large on-fault (supra-seismogenic) event rates; small, near-fault (subseismogenic) event rates; and truly off-fault (unassociated) event rates. The 24001006.001A/SAC24M163970 Page 6 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 supra-seismogenic ‘on-fault’ events are ultimately modeled using linear fault sources while the latter two categories (subseismogenic and off-fault) are considered ‘background seismicity’ and are modeled using spatially smoothed ‘grid’ of evenly spaced cells (a.k.a. gridded seismicity). The combined on-fault and off-fault solution set (fault system solution) used the logic tree solution framework shown in a generalized form on Attachment 4. Our model implements the branch-averaged solutions.

The on-fault seismicity considers two potential alternative fault models, equally weighted, identified as fault model 3.1 (FM 3.1) and fault model 3.2 (FM 3.2). These fault models each contain a slightly different collections of fault traces that are broken into ‘segments’ for modeling purposes, with individual segments strung together during evaluation to create hundreds of thousands of potential fault-based ruptures or multi-rupture events. In our model, fault segments are modeled with the recurrence rates constrained during the ‘grand inversion’ by the UCERF2 ‘characteristic’ inversion branch (e.g. Schwartz and Coppersmith, 1984). Fault slip rates (deformations) are constrained by a combination of a ‘pure’ geologic deformation model and three other models that consider geologic and geodetic data including the average fault block model, NewKinema model, and Zeng-Shen model. The magnitude-area relationships used along with the associated slip-length models, as well as other solution constraints applied, are shown with weights on Attachment 4 and are discussed in detail in Field et al. (2013) and associated publications.

Off-fault seismicity (e.g. background seismicity) recurrence rates are solved for simultaneously by the ‘grand inversion’. This off-fault background seismicity is intended to include all smaller earthquakes (Mw<~6.5) on major faults and earthquakes of all sizes that are not associated with known faults. The off-fault background seismicity considers spatial smoothing of a ‘grid’ of evenly spaced cells using the spatial probability density function (PDF) grids of off-fault seismicity from UCERF2 and UCERF3 (equally weighted), considering the regional constraints on the model including the total regional magnitudefrequency distribution (e.g. Gutenberg-Richter distribution), maximum off-fault magnitude, number of regional events per year greater than Magnitude 5, and other constraints as shown on the logic tree (see Attachment 4). The branch-averaged, gridded seismicity solution for each fault model, as implemented by Petersen et al. (2019), was used in the source model for this work.

We note that the catalog used in this work was not updated in 2019, as re-evaluation of the grand inversion scheme requires a supercomputer. However, the USGS reviewed the catalog used for UCERF3 and concluded that the addition of recent historical events to the catalog is not needed at this time, as the additional historical events in the last half decade typically will not significantly change the model results, with changes generally small, localized, and often near active faults, and thus already adequately modeled (Petersen et al., 2019).

5.1.5 Ground Motion Model’s (GMM’s)
This study makes use of response spectral attenuation relationships, also known as ground motion models (GMMs), in evaluations at the site as required by ER 1110-2-1806.

Site-specific ground motions can be influenced by the styles of faulting, magnitudes of the earthquakes, and local soil conditions. Other effects such as near-source or basin effects can also influence the ground motions. The GMM’s used to estimate ground motion from an earthquake source need to directly or 24001006.001A/SAC24M163970 Page 7 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 indirectly consider these effects. Many GMMs have been developed to estimate the variation of spectral acceleration with earthquake magnitude and distance from the site to the source of an earthquake.

We will use four of the Next Generation Attenuation (NGA) West 2 relationships including Abrahamson et al. (2014), Boore et al. (2014), Chiou and Youngs (2014), and Campbell and Bozorgnia (2014) with equal weights applied for all crustal faults (e.g. reverse, strike-slip, normal) included in the fault model.

The Idriss (2014) model has not been used as it is not valid at the larger distances used in this study (e.g. more than 150 km). The far-field subduction events (e.g. from Cascadia megathrust) were modeled using the relationships of Atkinson and Macias (2009), Abrahamson et al. (2016), and Zhao et al. (2006) with equal weights applied, except that for slab events the Atkinson and Macias (2009) relationship was excluded. Spectral acceleration values are obtained by averaging the individual hazard results. These GMM’s provide ‘mean’ (RotD50) values of ground motions associated with magnitude, distance, site soil conditions, and mechanism of faulting. The uncertainty in the predicted ground motion was taken into consideration by including a magnitude dependent standard error in the probabilistic analysis.

5.1.6 Control Points and Site Parameters
Evaluation of seismic hazard and model development for site specific studies is usually completed at a control point considered representative of a structure or facility. For this project, multiple control points along levee alignments will be considered for evaluation of seismic hazard for the levees associated with this project. Points along levee alignment are considered adequate as active faults are generally located at distance from the site, and thus, small differences due to control point location variation should be minimal. Spacing between control points will vary based on soil conditions and mapped accelerations, with maximum spacing of 1 km (3280 ft). The control points will be used in evaluation of distance terms (rx, rjb, rrup) required for the selected GMM’s.

The value of VS30 will be evaluated based on data from previous reports. Ground motions will be evaluated at the ground surface and consider average or best estimate shear wave velocity profiles applicable to the levee under consideration, without modification to the ground motions due to soft clay and liquefied soil response. Z1.0 and Z2.5 will be developed considering various geologic factors and estimates from the NGA West 2 correlations to develop best estimate values.

5.2 PHASE 1: SCREENING REVIEW OF EXISTING ANALYSIS
The purpose of the screening process is to identify sections where original analyses are determined to be deficient, and sections where updated analyses indicate potential deformation where original analyses did not.

Sections determined to be non-critical for seismic performance will not be used in analyses or presented in report.
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Newly developed PGA’s for critical sections will be compared to PGA’s from previous reports. If the new PGA value and associated earthquake magnitude are lower than the original values and the original analysis is found to be adequate, no further analysis is required for that section. If the original analysis determined the section is not susceptible to deformation, no further analysis is required, unless new PGA and/or earthquake magnitude show significant liquefaction susceptibility. Additionally, if the section was found to be failing in Flow Failure or High Vulnerability based on original PGA and earthquake magnitude, no further analysis will be required.

5.3 PHASE 2: TARGETED EVALUATION
The purpose of targeted evaluation is to determine susceptibility to deformation based on updated parameters.

A targeted evaluation is required for critical sections under two conditions, as follows:

1. The new PGA and earthquake magnitude is less than or equal than the original PGA, the original analysis is determined to be inadequate, and the Flow Failure factor of safety (FOS) with original PGA is greater or equal to 1

2. The new PGA and/or earthquake magnitude is greater than the original PGA, the original analysis or conditions classify the section as low or moderate vulnerability, and the Flow Failure FOS with original PGA is greater than 1
If the targeted section meets ULDC criteria, no further analysis is required. If the section does not meet ULDC criteria, Flow Failure and deformation must be analyzed using new seismic values. Flow Failure FOS and deformation results will be presented in Kleinfelder’s report and used in the development of the Seismic Performance Summary Report and Post-Earthquake Remediation Plan. 6 METHODOLOGY FOR EVALUATING SEISMIC VULNERABILITY
Seismic vulnerability evaluation will follow the guidance provided in DWR Guidance Document (DWR and URS, 2015). High, Moderate, and Low Vulnerability classifications will be based on the seismic deformation estimates. As mentioned earlier, all sections classified as High Vulnerability in the Phase 1 and Phase 2 screening process will not be analyzed.

The following steps are involved in assessing seismic vulnerability, Step numbers are associated with Key Steps described in Figure 1, Table 6-1 of the DWR Guidance Document (DWR and URS, 2015); see Attachment 2 for the workflow chart.

1. Perform liquefaction analysis using revised PGA and earthquake magnitude values using URS spreadsheets to delineate zones of liquefaction.

Based on the results of liquefaction, identify any additional cross section for analysis. We will be using the cross sections already developed for our previous studies. 24001006.001A/SAC24M163970 Page 9 of 13 February 8, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

2. For selected cross sections, estimate FOS against flow failure using residual strength for liquefiable materials and performing static slope stability analysis. If FOS is less than 1, the section is classified as “High Vulnerability” and no further analysis is needed.

If FOS against flow failure is greater than 1.3, section will be classified as “Low Vulnerability”, unless analysis for volumetric strain results in a higher vulnerability class.

Kleinfelder has previously performed extensive slope failure modeling along the levee alignments using SLOPE/W, a two-dimensional finite element computer modeling, a package included in the GEOSTUDIO software package, which is developed by Bentley Systems, Inc. It is anticipated that those models will be updated to the current version of GEOSTUDIO (2023.1.0) and utilized for Targeted Flow Failure analyses. New analyses may need to be developed on an as-needed basis. Idealized soil properties will be based on previous investigations and generalized parameters from DWR Guidance Document (DWR and URS, 2015). Water surface elevations for seismic flow failure analyses will be the higher of either average summer or average winter water surfaces, in accordance with DWR Guidance Document (DWR and URS 2015).

Slope failure analyses should consider all potential failure modes, including:
• Waterside and landside
• Deep and shallow
• Circular and wedge-shaped

3. If FOS against flow failure is between 1.0 and 1.3, a simplified seismic deformation analysis should be performed on the section. This involves computing a maximum horizontal seismic coefficient (Kmax) and performing a pseudo-static stability analysis using a horizontal seismic coefficient of 50% of the maximum value. This analysis will be performed using the same updated SLOPE/W models used in Step 2. If the resulting FOS is greater than 1.0, the section may be classified as “Low Vulnerability”.

Yield acceleration (Ky) values must then be estimated using pseudo-static analyses using the same SLOPE/W models used in Step 2. Yield acceleration is defined as the minimum horizontal acceleration resulting in a just-stable slope condition, i.e. FOS = 1.0. Yield acceleration should be developed for each potential failure mode.

A vertical Newmark-type deformation analysis should be performed based on the Kmax and Ky values determined above. The calculated Newmark displacement may be reduced by 30% for estimation of freeboard loss.

Volumetric settlement should be considered for sections with potentially liquefiable soils thicker than 20ft. Previous work performed by URS on ULE considered (N1)60-cs blow counts less than 15 as liquefiable and subject to volumetric settlement. This blow count criteria will be evaluated against new research and revised if necessary.
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Seismic vulnerability classification is determined by calculating freeboard loss as the sum of Newmark-type vertical deformation and volumetric settlement (if applicable). Freeboard loss is evaluated as a percentage of levee height (as measured from hinge point on the landside toe).

Engineering judgment should be used to determine damage to internal levee structures, and the seismic vulnerability class should be evaluated based on Table 6-1 from the DWR Guidance Document (URS and DWR, 2015) shown below.

Figure 1: Table 6-1 from DWR Guidance Document, Section 6.4

4. Advanced seismic deformation analyses as described in Attachment 2 are applicable only to frequently loaded levees and will not be considered for this analysis. 7 LIMITATIONS
This work was performed in a manner consistent with that level of care and skill ordinarily exercised by other members of Kleinfelder’s profession practicing in the same locality, under similar conditions and at the date the services are provided. The work performed was based on project information provided by client. Kleinfelder’s conclusions, opinions, and recommendations are based on a limited number of observations and data. It is possible that conditions could vary between or beyond the data evaluated.

Kleinfelder makes no other representation, guarantee, or warranty, express or implied, regarding the services, communication (oral or written), report, opinion, or instrument of service provided.

Conclusions contained in this report are based on review of existing information referenced in this report and Kleinfelder’s present knowledge of the project. It is possible conditions could vary from that contained in those documents. If conditions are encountered that differ from those described herein, the client is responsible for ensuring that Kleinfelder is notified immediately so that we may reevaluate the conclusions of this report.
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 The scope of services was limited. 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 the information presented herein.

Although risk can never be eliminated, more detailed and extensive studies yield more information, which may help understand and manage the level of risk.

All rivers, streams and lakes will flood eventually. This fact means that all levees will be called upon to combat floodwaters at some point. Levees reduce the risk of flooding. But no levee system can eliminate all risk of flooding. The term “certification” is not intended to provide a guarantee or warranty of the conditions of the levee or its performance and assumes the following 1) a certification by a registered professional engineer or other party does not constitute a warranty or guarantee of performance, expressed or implied; 2) certification of data is a statement that the data is accurate to the best of the certifier’s knowledge; and 3) certification of analyses is a statement that the analyses have been performed correctly and in accordance with sound engineering practices. A levee certification does not address or mitigate the inherent flood risk proposed to a particular community. 8 CLOSING
This seismic evaluation technical approach memorandum is for review by the subject project’s peer review panel for concurrence with the approach for the forthcoming site-specific ground motion hazard analysis. If you have questions regarding this memorandum or if we may be of further assistance, please contact the undersigned.

Sincerely,
KLEINFELDER, INC.

Ryan Hochstatter, EIT Zia Zafir, PE, GE
Staff Geotechnical Engineer Sr. Principal Geotechnical Engineer

ATTACHMENTS
Levee Systems and Component Levee Map
Seismic Workflow
Seismic Vulnerability Analysis – Key Steps (DWR Guidance Document, 2015, DWR and URS) UCERF3 Source Model Logic Tree
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

REFERENCES
___________________________________________________________________________________ Abrahamson, N., Gregor, N., Addo, K. (2016). BC Hydro Ground Motion Prediction Equations for Subduction Earthquakes. Earthquake Spectra, Volume 32, Issue 1, pp. 23-44.

Abrahamson, N.A., Silva, W.J., and Kamai, R. (2014). “Summary of the ASK14 Ground Motion Relation for Active Crustal Regions.” Earthquake Spectra, Vol. 30, No. 3, pp. 1025-1056.

California Department of Water Resources (DWR) (2012). Urban Levee Design Criteria.

Chiou, B S., and Youngs, R.R. (2014). “Update for the Chiou and Youngs NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra.” Earthquake Spectra, Vol. 30, No. 3, pp. 1117-1154.

Cornell, C.A. (1968). Engineering Seismic Risk Analysis, Bulletin of the Seismological Society of America, Vol. 58, No. 5.

Cornell, C.A. (1971). Probabilistic Analysis of Damage to Structures Under Seismic Loading, Dynamic Waves in Civil Engineering, London, Interscience.

Idriss, I. M. (2014). “An NGA-West2 Empirical Model for Estimating the Horizontal Spectral Values Generated by Shallow Crustal Earthquakes.” Earthquake Spectra, Vol. 30, No. 3, pp. 1155-1177.

Merz, H.L. and Cornell, C.A. (1973). Seismic Risk Analysis Based on a Quadratic Magnitude-Frequency Law, Bulletin of the Seismological Society of America, Vol. 63, No. 6.

Petersen, M.D., Moschetti, M.P., Powers, P.M., Mueller, C.S., Haller, K.M., Frankel, A.D., Zeng, Yuehua, Rezaeian, Sanaz, Harmsen, S.C., Boyd, O.S., Field, Ned, Chen, Rui, Rukstales, K.S., Luco, Nico, Wheeler, R.L., Williams, R.A., and Olsen, A.H. (2014). Documentation for the 2014 Update of the United States National Seismic Hazard Maps, USGS Open-File Report 2014-1091, 243 p., https://dx.doi.org/10.3133/ofr20141091.

Petersen, M.D., Shumway, A.M., Powers, P.M., et al. (2019). The 2018 Update of the US National Seismic Hazard Model: Overview of Model and Implications, Earthquake Spectra, Volume 36, Issue 1, pp. 5-41.

Powers, P.M. (2017). National Seismic Hazard Model Project Computer Code (NSHMP-HAZ) Software, https://doi.org/10.5066/F7ZW1K31.
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Schwartz, D.P. and Coppersmith, K.J. (1984). Fault Behavior and Characteristic Earthquakes: Examples from the Wasatch and San Andreas Fault Zones, Journal of Geophysical Research, Vol. 89, pp. 5681-5698.

Senior Seismic Hazard Analysis Committee (SSHAC) (1997). Recommendations for Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts, U.S. Nuclear Regulatory Commission, Report No. CR-6372.

URS (2015b). “Guidance Document for Geotechnical Analyses, Urban Levee Geotechnical Evaluations Program, Contract 4600008101,” dated April 2015.

United States Army Corps of Engineers (USACE). (1999). Engineering Manual (EM) 1110-2-6050 “Response Spectra and Seismic Analysis of Concrete Hydraulic Structures.” USACE (2000). Engineering Manual (EM) 1110-2-1913 “Design and Construction of Levees.” USACE (2013). Engineering and Design Technical Letter (ETL) 1110-2-580 “Guidelines for Seismic Evaluation of Levees.”
USACE (2016). Engineer Regulation (ER) 1110-2-1806 “Earthquake Design and Evaluation for Civil Works Projects.”
Zhao et al. (2006). Attenuation Relations of Strong Ground Motion in Japan using Site Classification Based on Predominant Period. Bulletin of the Seismological Society of America, V. 96, No. 3, pp. 898-913.

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Fremont
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Sacramento
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w
Natomas
Cross Canal
NEMDC
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American
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Folsom
Lake
Folsom
Arcade
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Roseville
Dry Creek
Mo
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on
Creek
Strawberry
Creek
Natomas Levees
Folsom Dam Joint Federal Project
(Auxiliary Spillway)
North Area
Streams Levees
South Sacramento
Streams Group Levees
American River
Levees
Sacramento River Levees
South of Confluence
Sacramento
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Legend
Federal Project Leveeor StructureNon Project Levee
03 1.75 .5
Scale in Miles
SAFCA Flood Control
System Features

KLEINFELDER SEISMIC RESPONSIBILITY REACH
North Beach Lake
Levee
ATTACHMENT B: Seismic Planning Services Responsibility Map Proposal For Geotechnical Engineer & Seismic Planning Services ULDC & FEMA Levee Certification Program
Sacramento Area Flood Control Agency Levee Systems
Sacramento and Sutter Counties, California
1 Figure
6-1
Seismic Vulnerability Analysis – Key Steps

URBAN LEVEE EVALUATIONS
Department of Water Resources
Division of Flood Management
Step 2: Perform Post-Seismic Stability Analysis
Step 3f: Calculate volumetric strain, if necessary
Step 3a: Compute Kmax using Figure 6-4
Step 3e: Estimate vertical deformation as 0.7 times total Newmark displacement
Step 3g: Assign seismic vulnerability class using Table 6-1 Step 3c: Compute Ky value for sliding mass
Step 3d: Compute Newmark displacement using Kmax, Ky, and Figure 6-5 Yes
Step 3b: Perform pseudo-static stability analysis using K=0.5 Kmax No
Classify as “Low Vulnerability” unless
Volumetric Strain (Step 3f ) results in a
higher vulnerability class
Is
FSPS < 1?
Yes
No
Perform post-seismic stability analysis
Continue to Step 3
No further analysis is needed.

APPENDIX B

GROUND MOTION PARAMETER SELECTION MEMORANDUM
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

GROUND MOTION PARAMETER SELECTION MEMORANDUM
DATE: February 9, 2024
TO: Mr. Pete Ghelfi, PE
Director of Engineering
Sacramento Area Flood Control Agency
1325 J Street, Suite 1700
Sacramento, CA 95814
FROM: Ryan Hochstatter, EIT
Zia Zafir, PhD, PE, GE
SUBJECT: Revised Seismic Evaluation Ground Motion Parameter Selection Memorandum ULDC & FEMA Levee Certification Project
Sacramento Area Flood Control Agency Levee Systems
Sacramento and Sutter Counties, California
____________________________________________________________________________

INTRODUCTION
This technical memorandum presents the regional ground motion hazard analysis (GMHA) approach and inputs, including the development of peak horizontal acceleration (PHA) and design response spectral values to support the seismic vulnerability evaluation of levees located in the Sacramento Area of California consistent with the requirements of the Urban Levee Design Criteria (DWR, 2012).

This memorandum has been prepared consistent with the requirements of the approved scope of work for the subject project outlined in our proposal dated May 5, 2023, as well the GMHA methodology described in our Seismic Evaluation Technical Approach Memorandum dated September 5th, 2023.

PURPOSE
Sacramento Area Flood Control Agency (SAFCA) is working with a team of consultants to obtain ULDC and Federal Emergency Management Agency (FEMA) certifications for the Sacramento area levees. The purpose of this document is to provide ground motions in terms of peak horizontal acceleration (PHA) based on the new seismic sources and ground motion models. Development of ground motions follow the methodology presented in our Technical Approach Memorandum dated September 5, 2023.

The levees will be organized by selection of “sections” instead of reaches due to the variable nature of subsurface conditions under levees. Sections may overlap multiple reaches or reaches may be subdivided into multiple sections. Note that for sections encompassing or divided by roadway overcrossings, the overcrossings will be simplified to their centerlines, and additional improvements to the levee for overcrossing abutments will be neglected. 24001006.001A/SAC23M158525_R2 Page 2 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

PROJECT FEATURES
Figure 1 shows the following levee systems and their associated component levees. The levee systems are summarized in Table 1 below.

Table 1
Levee Systems and Component Levees
Levee System Reach
1 - Dry Creek Dry Creek North Levee
2 - Robla-Arcade
Dry Creek South / Robla Levee
Natomas East Main Drainage Canal (NEMDC) East Levee - Robla to Arcade Creek Arcade Creek North Levee
3 - American
North
Arcade Creek South Levee
NEMDC East Levee - Arcade Creek to American River
American River North Levee
4 - American
South
American River South Levee
Sacramento River East Levee (SREL) -American River to NBLL North Beach Lake Levee
5 - Natomas
Basin
Natomas Cross Canal South Levee (NCC)
SREL - NCC to Powerline Road
SREL - Powerline Road to American River
American River North Levee - Sacramento River to NEMDC
NEMDC West Levee
Pleasant Grove Creek Canal (PGCC) West Levee

GOVERNING STANDARDS
Methodology for conducting seismic vulnerability evaluation of levees is governed by design criteria developed by the California Department of Water Resources (DWR). Relevant publications that will be the primary source for Kleinfelder’s analysis includes:
• Urban Levee Design Criteria (ULDC, 2012) “Section 7.7 – Seismic Vulnerability” • Urban Levee Evaluations Project Guidance Document for Geotechnical Analysis (ULE, 2015), DWR and URS, “Section 6.0 – Seismic Analysis”
Additionally, ground motion parameter development for evaluations is governed by applicable US Army Corps of Engineer’s Regulations and Manuals (ER & EM). Design guidance applicable to the seismic evaluation includes:
• Engineering Manual (EM) 1110-2-1913 (April 2000, USACE) “Design and Construction of Levees” • Engineer Regulation (ER) 1110-2-1806 (May 2016, USACE) “Earthquake Design and Evaluation for Civil Works Projects”
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 • Engineering and Design Technical Letter (ETL) 1110-2-580 (March 2013, USACE) “Guidelines for Seismic Evaluation of Levees”

SEISMIC SOURCE INPUTS
General
Site characterization was completed in general accordance with ER 1110-2-1806 §8. In general, this includes characterization of the topographic, hydrologic, and geologic/stratigraphic characteristics of the site and the associated engineering properties as needed for seismic evaluations.

Regional Setting
The regional setting is used in developing seismic source models and informs the interpretation of local geology. The regional setting includes discussion of the regional geology and stratigraphy, seismotectonic setting, faulting and fault rupture, and historic seismicity. Details are discussed below.

Regional Geologic Setting
The study area is located within the southern portion of the Sacramento Valley, within the Great Valley geomorphic province. The Great Valley province is a north-south trending 400-mile by 50-mile long alluvial plain in central California comprised of the Sacramento Valley in the north and the San Joaquin Valley in the south. The Sacramento Valley contains thousands of feet of accumulated fluvial, overbank, and alluvial fan deposits derived from erosion of the adjacent Sierra Nevada mountains to the east, northern Coast Range mountains to the west, and Klamath and Cascade mountains to the north. These deposits are primarily comprised of Quaternary and Tertiary age (present day to 56 million years ago) alluvial deposits and include clays, silts, sands, and gravels. The alluvial deposits thin out at the margins of the Great Valley Province, exposing underlying bedrock units. The Foothills Metamorphic Belt and the basement complex of the Sierra Nevada Batholith to the east are exposed along the eastern boundary of the valley. Sedimentary and mélange bedrock of the northern Coast Range mountains are exposed to the west. Meta-sedimentary, mélange, igneous, and volcanic bedrock of the Klamath and Cascade mountains are exposed to the north.

The study area has been regionally mapped by a number of geologists. These include published maps by Wagner et al. (1981), Helley and Harwood (1985), Gutierrez, C.I. (2011), and Fugro William Lettis & Associates (FWLA, 2010). Wagner et al. (1981) provides the most regional context but very little detail relative to the project area. Helley and Harwood mapping (performed at a scale of 1:62,500) focuses on Quaternary geologic units based on geomorphology. Gutierrez, C.I. (2011) is the most recent map of the study area and provides more current regional geologic mapping relative to Helley and Harwood (1985).

Fugro William Lettis & Associates (FWLA, 2010) provides more detailed surficial Quaternary deposits.

The project area is shown on Wagner D. L. (1981) on Figure 1.

Subsurface Stratigraphy at Depth
The Great Valley geomorphic province is characterized as an elongated low-lying basin through central California filled with thousands of feet of sediment. The Great Valley province is situated on the remnants of the Jurassic age forearc basin of the Pacific Plate subducting under the North American Plate. The forearc basin is a regional and asymmetrical feature with the western portion being deepest 24001006.001A/SAC23M158525_R2 Page 4 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 (Harwood and Helley, 1987). The sediment within the basin is referred to collectively as the Great Valley Sequence, comprised of present day to Eocene age alluvial deposits. Underlying the Great Valley Sequence are Cretaceous age marine sedimentary rocks such as shales and sandstones. Underlying the marine sedimentary rocks is an ophiolite suite which is typically comprised of ultramafic (i.e. periodite and dunite) to mafic rocks (i.e. gabbro and basalt) overlain by shale and chert (Harden 1998).

Seismotectonic Setting
The site is located in the Western United States (WUS) in the transform plate boundary region between the Pacific Plate (transitioning northwest) and the North American Plate (see Figure 4). The site lies within the Sierra Nevada-Great Valley block (a.k.a., the Sierra Nevada microplate, or SNGV) which generally is thought to act as an independent block that has ‘tilted’ westward. The SNGV block is bounded on its eastern edge by a zone of faults known as the Walker Lane Belt, beyond which is the crustal extensional region of the Northern Basin and Range. Further afield in the northwestern portion of the state and extending northward to the pacific northwest, the Juan de Fuca plate is currently subducting below the North American plate in a region known as the Cascadia Subduction Zone (Humphreys and Coblentz, 2007; Unruh and Humphrey, 2003, 2017).

Regional stress build-up due to the northwestern movement of the Pacific Plate is primarily released through displacement along faults within the San Andreas fault system (e.g. San Andreas fault, Hayward fault, etc.) and to a lesser extent by displacements along faults within the Walker Lane Belt. Crustal extension of the Northern Basin and Range has led to the development of stress in the east-west direction and caused development of an extensive system of faults within the Northern Basin and Range (Fey and Humphreys, 2008; Field et al., 2013).

Faults and Fault Rupture
Regional faulting and potential for fault rupture directly impact the potential sources of seismicity and thus the seismic risk at a site. For this study, Quaternary age faults (considered potentially seismically active) were reviewed consistent with the recommendations of EM 1110-2-1806. Based on our review, a number of Quaternary and older faults were identified as shown on Figure 3, with select Quaternary faults within 100 km1of the site listed in Table 2. Detailed discussion of faulting and potential for fault rupture is provided below.

The closest potentially active system to the site is the Great Valley fault system which lies to the west of the site. The closest segments of the Great Valley system include the Midland fault2located roughly 30 km to the southwest of the site (DWR, 2007; Unruh and Hitchcock, 2009), and the Dunnigan Hills3thrust fault which lies to the west-northwest (Jennings and Bryant, 2010; Parrish, 2018). Other significant active faults to the west of the site include faults within the San Andreas system (San Andreas fault, Hayward fault, Calaveras fault, etc.). East of the site, the active fault systems include the Foothills fault system (Paynes Peak fault, Spenceville fault, Maidu East fault, etc.) and a series of strike-slip and normal 1 A 100 km distance was used in the table for consistency with the distance to which more detailed seismic source characterization was completed, see Section 3.3 for details.
2 The Midland fault zones northern extension consists of somewhat complex geometry in the vicinity of Rio Vista and northward. Detailed geometry not shown in this report, see Unruh and Hitchcock (2009) for details. 3 The Dunnigan Hills (aka. Zamora Fault) is mapped by some researchers along the northeastern edge of the Dunnigan Hills (Harwood and Helley, 1987; USGS and CGS, 2006). However, the active fault has more recently been mapped to the southwest by Parrish (2018) and others and is considered more appropriate for evaluation of active and potentially active portion of the fault in this study. 24001006.001A/SAC23M158525_R2 Page 5 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 faults in and around the Tahoe region, as well as faults associated with crustal extension of the Northwestern Basin and Range. Much further afield, the Cascadia subduction zone (northwest corner of the state) can generate very large magnitude events and may have the potential to impact long-period ground motions at the site.

There are a series of older faults and folds that underlie the central part of the Great Valley and include the possible southeastern extension of the Willows fault and the Stockton fault. The Willows and Stockton faults are generally accepted to be seismically inactive, with deformation along the southern end of the Willows fault (closest fault to the site) considered to be older than about 3.4 million years (Harwood and Helley, 1987). Along the western edge of the Sacramento Valley, the Thornton Arch4as well as the East and West Valley faults are, likewise, considered seismically inactive with the most recent activity generally considered pre-quaternary in age (Jennings and Bryant, 2010; Parrish, 2018). These inactive faults are not considered to be significant to hazard potential at the site and thus are not listed in Table 2 although they are shown on Figure 3 for completeness.

Table 2
Potentially Active or Active Quaternary Age or Younger Faults Within 125 Km of Site Name Name Name
Alexander fault Greenville fault Poorman Gulch fault
Antioch fault Haupt Creek fault Pope Creek fault
Ashland fault Hayward fault Putah Creek
Bad Ridge fault Highway 49 fault Putah Creek fault
Bartlett Springs fault zone Hunting Creek fault Red Road fault Bennett Valley fault Hunting fault Redwood Hill fault
Black Butte fault Ione fault Rescue fault
Bowie Flat fault Kennedy fault Resort fault
Burdell Mountain fault Kirby Hills fault Rio Vista fault Calaveras fault Konocti Bay fault Rodgers Creek fault
Carnegie fault Lagoon Valley fault San Joaquin fault
Chabot fault Lakeview fault Sherburne Hills thrust fault Chico Monocline fault Little Indian Valley fault Soda Creek fault Clayton fault Livermore fault Southampton fault
Cleveland Hill fault Los Positas fault Spenceville fault Clover Valley fault Maacama fault Swain Ravine fault
Cobb Mountain fault Maidu East fault Tolay fault
Concord fault Marsh Creek fault unnamed
Cordelia fault Maxwell Creek fault Vaca fault
Corning fault Midland fault Vernalis fault
Corral Hollow fault Midway fault Verona fault
Cross Spring fault Mill Valley fault Waters Peak fault
Deadman fault Miller Creek fault West Napa fault
4 Previous studies by the California Department of Water Resources (DWR, 2007) have considered possible activity (probability of activity of 20 percent) along the Thornton Arch. However, Jennings and Bryant (2010) and other more recent studies by the various researchers have not considered this feature to be potentially active.
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Name Name Name
Dewitt fault Mocho fault Wildcat fault
Dunnigan Hills fault Moraga fault Williams fault
Franklin fault Northern Calaveras fault Wilson fault
Giant Gap fault Paynes Peak fault Youngs Creek fault
Green Springs Run fault Pinole fault
Green Valley fault Pleasanton fault
Notes:

Refer to Figure 3 for relative fault distances from project.

Historic Seismicity
One of the major factors for evaluation of seismic hazard is the historic record of seismicity. Patterns of historic seismicity can be used to identify known or inferred impacts of historical seismicity on a project.

Catalogs of historic seismicity are also used to characterize seismic sources in models such as those developed by Field et al. (2013) and others. This section discusses regional historic seismicity.

Kleinfelder compiled and reviewed data from the USGS ANSS Comprehensive Earthquake Catalog, known as ComCat, which contains historical seismic data compiled by the USGS from multiple sources. A search radius of 300 km centered on the site was used and yielded a record covering the years from 1808 to 2019.

Based on review of this data, the closest seismic events to the site are a set of minor events (Mw < 4) that occurred in 2002 located about 15 to 16 km northwest of the site. Another minor event occurred in 2003 located about 16 km to the southeast of the site. These events constitute the only recorded seismicity in the near-field vicinity (e.g. within about 15km) of the site and are small enough not to be of engineering significance.

More significant historic seismicity has been observed along some of the nearby active faults (see Figure 3). Historical seismicity along the Great Valley thrust fault system includes a cluster of low magnitude events near the south end of the Dunnigan Hills section. Other events along the Great Valley system include the 1892 (~Mw6.6) Vacaville-Winters sequence near the Gordon Valley section and the 1892 (Mw5.5) event near the Midland Fault (Unruh and Moores, 1992; USGS, 2019). The foothills fault system has also historically been active, with a large number of earthquakes observed near Oroville Dam (possibly reservoir induced seismicity) and significant micro-seismicity reported between Oroville and Folsom reservoirs, particularly near the Rocklin-Penryn pluton (e.g. Cramer et al, 1978).

Far-field events include a number of significant large earthquakes including the 1868 (Mw7.0) Hayward earthquake, the 1906 (Mw7.8) “Great” San Francisco earthquake, the 2014 (Mw6.0) South Napa earthquake, the 1838 (Mw7.4) San Francisco Peninsula earthquake, the 1865 (Mw6.5) Santa Cruz Mountains earthquake, and the 1989 (Mw6.9) Loma Prieta earthquake. These events are located on faults within the San Andreas fault system (Hayward, San Andreas, etc.). Review of the historic records indicates only minor impacts or damage from these events in the Sacramento region.

Intensity values such as Modified Mercalli Intensity (MMI) tend to provide an indication of the effect of historic seismicity on people and buildings and are useful in measuring the significance of events at a site. MMI values in this study were estimated using the relationship of Atkinson et al. (2014). The majority of the historic earthquake event data used in the evaluation was obtained from the USGS 24001006.001A/SAC23M158525_R2 Page 7 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 National Seismic Hazard Map project de-clustered earthquake catalog (e.g. Petersen et al. 2014). A table of historically significant seismic events, based on MMI, is provided below in Table 3. The most significant events impacting the site from this evaluation are highlighted in bold. These include the 1892 Vacaville-Winters sequence (e.g. Great Valley fault system) and the 1906 “Great” San Francisco earthquake (e.g. San Andreas fault system).

The estimated MMI values were checked against historic data for select events. For a recent event, the MMI reported by the USGS from observations for the South Napa event was 3.5 and is consistent with the estimated MMI. Some older events have reported MMI values as high as VI to VII based on record review by the California Geological Survey (CGS, Historic Earthquake Online Database, accessed 2020).

However, it is likely that these higher MMI values are influenced by lower quality of construction generally prevalent at the time.

Table 3
Select and Significant Historic Earthquakes and
Estimated Historical Impact Potential Using MMI
Magnitude
(Mw)
Event Date Event Name/Location4
Estimated
MMI1,2

7.4 6/1/1838 San Francisco Peninsula IV

7.3 1/1/1852 Pyramid Lake IV

7.9 1/9/1857 Great Fort Tejon IV

7.0 10/21/1868 Hayward IV

6.0 5/19/1889 Near Collinsville IV

6.6 4/19/1892 Vacaville-Winters Earthquake V

6.4 3/31/1898 Mare Island IV

7.8 4/18/1906 “Great” San Francisco V

6.9 10/18/1989 Loma Prieta IV

6.0 8/24/2014 South Napa3IV
Notes:

1. Approx. Modified Mercalli Intensity (MMI) developed using procedure of Atkinson et al. (2014).

2. MMI – IV- Light Shaking; V – Moderate Shaking; VI – Strong Shaking; VII – Very Strong Shaking; VIII – Severe Shaking; IX – Violent Shaking; X – Extreme Shaking (USGS.gov accessed 2020)

3. 2014 Napa earthquakes data from USGS earthquake hazards program (https://earthquake.usgs.gov/ earthquakes/eventpage/nc72282711/executive).

4. Some events including Santa Cruz Mountains earthquake (1865), induced seismicity sequence near Oroville, and microseismicity, etc. not listed due to low impact/magnitude.

GMHA IMPLEMENTATION
To be consistent with previous work performed by URS and DWR for the Urban Levee Evaluations (ULE) project, the probabilistic seismic hazard analysis (PSHA) approach was selected to perform the GMHA for this study and estimate the ground motion parameters (typically peak ground and spectral accelerations), with some modifications in implementation based on current standards of practice for probabilistic evaluations in California (e.g., “Grand Inversion” approach). Only the probabilistic approach is used, which is consistent with requirements of ULDC, and as permitted by ER 1110-2-1806 §7d. 24001006.001A/SAC23M158525_R2 Page 8 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Existing Ground Motion Data
Previous development of ground motion parameters in the area was performed by URS in 2007 as part of the Delta Risk Management Strategy (DRMS), which was updated and expanded on in 2012 by URS as part of the Department of Water Resources’ (DWR) Urban Levee Evaluation (ULE) project. A 200-year return period seismic hazard map was developed for the ULE area, which encompasses the ULDC area.

The probabilistic seismic hazard analysis performed for the ULE area was based on the UCERF2 seismic source characterization. The ground motion parameters developed by URS consisted of peak horizontal acceleration for stiff soil condition where Vs30 was taken as 335 m/s (1100 ft/s), which typically occurs depths of 100 to 120 feet below the ground surface. In addition, associated earthquake magnitude was also estimated.

For this project the source characterization by others will be reviewed, where high-quality peer reviewed seismic source models are available. This will include studies performed by the United States Geological Survey applicable to the project region (e.g. Petersen et al. 2014, 2019), statewide studies performed as part of the third Uniform California Earthquake Rupture Forecast (UCERF3 - Field et al., 2013). It is expected the UCERF3 characterization will be primarily used for this project due to its wide adoption in other work and for consistency with the deprecated UCERF2 model used in previous work by URS. Additionally, Petersen et al. (2014, 2019) models will be used for far-field seismic sources outside of California (e.g. Cascadia, etc.)
Analysis performed by URS in 2012 for ULE identified several potential seismic sources in the area that were not included in the UCERF2 model (i.e. Northern Midland fault zone). The UCERF3 model will be evaluated for inclusion of these sources.

Following evaluation of existing design ground motion data, segments of levee with either non-existent or out-of-date seismic data will be analyzed according to procedures described below.

Probabilistic Seismic Hazard Analysis (PSHA)
The PSHA approach that will be used to estimate the ground motion parameters (typically peak ground and spectral ground accelerations) is generally consistent with requirements of ULDC, with some modifications in implementation based on current standards of practice for probabilistic evaluations in California (e.g. “Grand Inversion” approach). The probabilistic approach is used in place of a deterministic approach as permitted by ER 1110-2-1806 §7d.

The PSHA uses a logic tree approach to account for epistemic uncertainty in the model, with aleatoric variability accounted for in the uncertainty associated with various models (e.g. GMM’s). The logic tree 24001006.001A/SAC23M158525_R2 Page 9 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 is developed to account for uncertainties in the source models, ground motion models, and other items impacting the results. Important source characteristics include slip rates and fault lengths, magnitude and recurrence intervals of potential seismic events, distance from the site to the causative source, and other parameters. The effects of site soil conditions, and other considerations such as basin effects, can be accounted for using ground motion models (GMMs).

𝑃𝐸
(𝑧) = 1 −𝑒𝑥𝑝 𝑒𝑥𝑝 (−𝑣(𝑧) ∗ 𝑡)
Different probabilities of exceedance may be selected, depending on the level of performance required.

The return period is essentially equivalent to the reciprocal of v(z).

The PSHA is conducted using three generalized steps that include the following.

1. Development of an appropriate seismic source model including source characterization, development of recurrence relationships, and appropriately capturing uncertainty

2. Selection of appropriate ground motion models (and site amplification models, if appropriate)

3. Conducting the calculation and processing the results The annual frequency of exceedance of a certain ground motion level can be found by summing the rates for all sources, N, with the rate for each source determined by summing over all magnitudes and source to site distances, and so forth. The annual frequency of occurrence of earthquakes of magnitude, mi, on seismic source, n, is λ(mi). The probability of an earthquake of magnitude, mi, on source, n, occurring at a certain distance, rj, from the site is P(R = rj | mi) while the probability that the ground motion level, z, will be exceeded is given as P(Z>z | mi,rj). Thus, mathematically the basic formulation for the annual frequency of exceedance, v(z), is given by (EM 1110-2-6050):
𝑣(𝑧) = ∑
𝑁
[ ∑
𝑀
𝜆(𝑚𝑖
) ∗ ∑
𝑅
𝑃(𝑚𝑖
) ∗ 𝑃(𝑚𝑖
, 𝑟𝑗)]
Modern computers make the above calculation, while computationally expensive, easily implementable at most sites. We will use the computer program HAZ (Powers, 2017) for our probabilistic analysis, which implements the above general equation. Uncertainties are accounted for within the source model using a logic tree approach and using multiple models, where appropriate. We note that HAZ does not currently provide the uncertainty bands (16th and 84th percentiles) and thus uncertainty bands will not be evaluated or presented.
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Seismic Source Model
The seismic source model for a site contains all information required to characterize potential seismic sources for use in evaluation of ground motion parameters. The source model typically includes information on the geometry (e.g. length, dip, depth, etc.), style of faulting, magnitude, and recurrence relationships for all potentially active seismic sources within a distance capable of significantly impacting a site. The source model used for this work is discussed below.

Detailed review of select nearby seismic sources was performed and included review of the Midland fault, Dunnigan Hills fault, Foothills fault system, and other nearby faults. Other faults are not discussed in detail, but discussion is available in the referenced literature:
• Midland fault - The Midland fault was not considered active by Petersen et al. (2008). However, DWR (2007) and follow on work by Unruh and Hitchcock (2009) conclusively showed ongoing activity along the Midland fault within the Sacramento-San Joaquin delta. The Midland fault was characterized by DWR (2007) using a source zone to represent the northern portion of the Midland fault zone, while other later studies (Merriam, 2012; Petersen et al. 2019, etc.) generally considered this source adequately characterized using a linear fault source, and that approach was considered appropriate for this study.
• Dunnigan Hills fault - Consideration of an alternative placement of the Dunnigan Hills fault (east of the Dunnigan Hills), as was done by Merriam (2012), was not considered justified based on available geologic data.
• Thornton Arch - The Thornton arch zone, a potential seismic source identified by DWR (2007), was not modeled as an independent source by most other studies. This study likewise does not explicitly consider this as a potentially active fault source based on the lack of significant folding of the overlying Miocene age continental rocks, leading to the conclusion that the structure is pre-Miocene (e.g. Harwood and Helley, 1987).
• Foothills system - The Foothills fault system (Swain Ravine fault, Spenceville fault, Dewitt fault, etc.) was modeled as a source zone by some studies or as a fault source in more recent work for UCERF3. The fault source approach and characterization of UCERF3 (e.g. Swain RavineSpenceville Fault) was adopted in this study. • Other minor faults: Other nearby, potentially active faults (e.g. Vernalis Fault, Rio Vista Fault, Black Butte fault, etc.) were generally not considered significant to the hazard at the site. These sources were not considered as independent seismogenic sources and were more appropriately modelled by background seismicity.

We used the above characterization to review available source models and determine if any site-specific modification to the models was required.

We reviewed source characterization and seismic models developed by others where high-quality peer reviewed models were available. Available models reviewed for this work included studies performed by the USGS applicable to the project region (e.g., Petersen et al. 2019), which generally adopted the results of the statewide study performed as part of the third Uniform California Earthquake Rupture 24001006.001A/SAC23M158525_R2 Page 11 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Forecast (UCERF 3 - Field et al. 2013), and the regional study completed by the California Department of Water Resources (DWR) for the Delta Risk Management Strategy project (California DWR, 2007).

Based on the above characterization and review of the available models, the source model developed by the USGS and published by Petersen et al. (2014, 2019) was generally found to provide adequate characterization of seismic sources and uncertainties identified for inclusion in the model. No sitespecific modification was needed for this study, and thus, the model of Petersen et al. (2014, 2019) was adopted for this work without change.

Within the Western United States (WUS) region, significant independent seismogenic sources within about 300 kilometers (km) of the site are included in the model as fault sources. Very large magnitude sources, such as the Cascadia subduction zone, are included out to 500 km. Minor, potentially active faults are generally not considered significant to the seismic hazard at the site. These sources were not considered as independent seismogenic sources and were more appropriately modelled by background seismicity. Recurrence intervals and slip rates used to develop the fault models are available in referenced literature and are based on the values developed by the UCERF 3 working group.

The adopted model uses two alternative fault models, Fault Model (FM) 3.1 and FM 3.2, from the branch-averaged UCERF 3 solution to model on-fault seismicity in California. Off-fault seismicity, also known as background seismicity, is modeled using gridded seismic sources developed for consistency with each fault model. Outside of California (e.g., Cascadia, etc.), source characterization developed by Petersen et al. (2014, 2019) was used.

The seismic source model used for this work within 325 km of the site is presented on Figure 4. An abbreviated overview of significant fault sources included in the source model within 100 km of the site is provided in Attachment A1. The attached table presents a simplification of the model used for this study and does not show how the model relaxes the assumption of segmentation and allows for multifault ruptures, with numerous possible combinations. For additional details of the characterization of individual sources and associated alternative models (e.g., FM 3.1 vs FM 3.2), the reader can refer to the documentation prepared by Petersen et al. (2014, 2019) and the associated referenced documents and reports.
‘Grand Inversion’ and Recurrence Rates
The earthquake recurrence rates used in the source model will be adopted as developed by the UCERF3 project, as implemented by Petersen et al. (2019) using the branch-averaged solutions of the ‘grand inversion’. This is a departure from the older standard of practice documented in EM 1110-2-6053 and Draft EM 1110-2-6000, which solves for the entire system of faults within California simultaneously.

The ‘grand inversion’ scheme developed by the UCERF3 project team, the results of which will be adopted in this work, ‘solved’ the on-fault and off-fault recurrence rates at a system level using a set of defined constraints including the spatial probability density of off-fault seismicity, slip rate balancing, paleoseismic even rate matching, fault smoothness constraint, regional magnitude frequency distribution constraints, and fault section specific magnitude frequency distribution constraints. In simple terms the ‘grand inversion’ solves for three things: large on-fault (supra-seismogenic) event rates; small, near-fault (subseismogenic) event rates; and truly off-fault (unassociated) event rates. The 24001006.001A/SAC23M158525_R2 Page 12 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 supra-seismogenic ‘on-fault’ events are ultimately modeled using linear fault sources while the latter two categories (subseismogenic and off-fault) are considered ‘background seismicity’ and are modeled using spatially smoothed ‘grid’ of evenly spaced cells (a.k.a. gridded seismicity). The combined on-fault and off-fault solution set (fault system solution) used the logic tree solution framework shown in a generalized form on Figure 5. Our model implements the branch-averaged solutions.

The on-fault seismicity considers two potential alternative fault models, equally weighted, identified as fault model 3.1 (FM 3.1) and fault model 3.2 (FM 3.2). These fault models each contain a slightly different collections of fault traces that are broken into ‘segments’ for modeling purposes, with individual segments strung together during evaluation to create hundreds of thousands of potential fault-based ruptures or multi-rupture events. In our model, fault segments are modeled with the recurrence rates constrained during the ‘grand inversion’ by the UCERF2 ‘characteristic’ inversion branch (e.g. Schwartz and Coppersmith, 1984). Fault slip rates (deformations) are constrained by a combination of a ‘pure’ geologic deformation model and three other models that consider geologic and geodetic data including the average fault block model, NewKinema model, and Zeng-Shen model. The magnitude-area relationships used along with the associated slip-length models, as well as other solution constraints applied, are shown with weights on Figure 5 and are discussed in detail in Field et al. (2013) and associated publications.

Off-fault seismicity (e.g. background seismicity) recurrence rates are solved for simultaneously by the ‘grand inversion’. This off-fault background seismicity is intended to include all smaller earthquakes (Mw<~6.5) on major faults and earthquakes of all sizes that are not associated with known faults. The off-fault background seismicity considers spatial smoothing of a ‘grid’ of evenly spaced cells using the spatial probability density function (PDF) grids of off-fault seismicity from UCERF2 and UCERF3 (equally weighted), considering the regional constraints on the model including the total regional magnitudefrequency distribution (e.g. Gutenberg-Richter distribution), maximum off-fault magnitude, number of regional events per year greater than Magnitude 5, and other constraints as shown on the logic tree (see Figure 5). The branch-averaged, gridded seismicity solution for each fault model, as implemented by Petersen et al. (2019), was used in the source model for this work.

Ground Motion Model’s (GMM’s)
This study makes use of response spectral attenuation relationships, also known as ground motion models (GMMs), in evaluations at the site as required by ER 1110-2-1806.

Site-specific ground motions can be influenced by the styles of faulting, magnitudes of the earthquakes, and local soil conditions. Other effects such as near-source or basin effects can also influence the ground motions. The GMM’s used to estimate ground motion from an earthquake source need to directly or 24001006.001A/SAC23M158525_R2 Page 13 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 indirectly consider these effects. Many GMMs have been developed to estimate the variation of spectral acceleration with earthquake magnitude and distance from the site to the source of an earthquake.

The Idriss (2014) model has not been used as it is not valid for the VS30 used in our study and also for the larger distances used in this study (e.g. more than 150 km). The far-field subduction events (e.g. from Cascadia megathrust) were modeled using the relationships of Atkinson and Macias (2009), Abrahamson et al. (2016), and Zhao et al. (2006) with equal weights applied, except that for slab events the Atkinson and Macias (2009) relationship was excluded. Spectral acceleration values are obtained by averaging the individual hazard results. These GMM’s provide ‘mean’ (RotD50) values of ground motions associated with magnitude, distance, site soil conditions, and mechanism of faulting. The uncertainty in the predicted ground motion was taken into consideration by including a magnitude dependent standard error in the probabilistic analysis.

Deep Sediment Impact on Response
The Sacramento Basin, while not typically considered a true basin for purposes of seismic evaluation, does contain deep sediments which can impact the response of the system. The Campbell and Bozorgnia (2014) and Chiou and Youngs (2014) GMMs include the depth to rock (Z) parameter to better predict ground motion in regions with deep sedimentary structure. The Campbell and Bozorgnia (2014) model uses the depth to shear wave velocity of 2.5 km/s (Z2.5) and the Chiou and Youngs (2014) model uses the depth to shear wave velocity of 1.0 km/s (Z1.0). The Z1.0 and Z2.5 values can be estimated by various sources, as discussed in next section. For Northern California locations, only the Campbell and Bozorgnia (2014) factor is applied, to account for deep sedimentary structure which is analogous to a ‘basin effect’.

Therefore, the basin effect on the response spectrum either at depth or at ground surface can be considered using the appropriate site-specific Z1.0 and Z2.5 values. Previous work on DRMS (DWR, 2007) determined that the response of the levees as more sensitive to ground potions with a period lower than 1 second, so the longer period motions where deep basin effects would be most pronounced are likely not significant to the levees of this project.

Control Points and Site Parameters
Evaluation of seismic hazard and model development for site specific studies is usually completed at a control point considered representative of a structure or facility. For this project, multiple control points across the project area are considered for evaluation of ground motions. Nine points along levee alignment are considered adequate as active faults are generally located at distance from the site, and thus, small differences due to control point location variation should be minimal. The control points will be used in evaluation of distance terms (rx, rjb, rrup) required for the selected GMM’s.

The above GMMs also use a set of site parameters to account for site effects and basin effects. For the NGA West 2 relationships, these include the average shear wave velocity in the upper 100 feet (30 meters, e.g. VS30), the depth to a layer with a Vs value of 3,280 feet per second (1,000 meters per second, e.g. Z1.0), and the depth a layer with Vs value of 8,200 feet per second (2.5 km/s, e.g. Z2.5). 24001006.001A/SAC23M158525_R2 Page 14 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 The VS30 values were evaluated at depth based on data from previous reports and mapped values. for consistency with DMRS (DWR, 2007), ground motions were evaluated as a stiff soil condition where VS30 is taken as 335 m/s. it is understood that this condition typically occurs at a depth of about 100 to 120 feet below ground surface. Z1.0 and Z2.5 were developed considering various geologic factors and estimates from the NGA West 2 correlations to develop best estimate values.

The Z1.0 and Z2.5 parameters are intended to capture the basin effects on ground motion response at a given site. The Z1.0 and Z2.5 values were estimated utilizing the correlations developed for the NGA West 2 project, with justification per Petersen et al. 2019. The Z1.0 and Z2.5 values are estimated to be about

0.428 km and 1.55 km, respectively. We propose to use these values as inputs for the GMHA.

In summary, our recommended values of VS30, Z1.0, and Z2.5 are presented in Table 4 below. Further details about the development of the site parameters are presented in Attachment A2.

Table 4
Site Parameters
Point ID Latitude Longitude VS30
(m/s)
Z1.0
(km)
Z2.5
(km)
Natomas NE 38.8262 -121.5317
335 0.428 1.55
Natomas NW 38.7810 -121.6025
Natomas West 38.6904 -121.6325
Arcade Creek 38.6668 -121.4762
Confluence 38.5982 -121.5087
American River East 38.5921 -121.3344
Little Pocket 38.5293 -121.5288
Pocket 38.4989 -121.5578
SREL South 38.4447 -121.5002
Peak Horizontal Accelerations
The probabilistic geometric mean peak horizontal acceleration is taken as the geometric mean peak horizontal acceleration with a 200-year return period. The associated controlling earthquake magnitudes and distances are based on the results of the deaggregation analysis. These values are presented in Table 5. We have also provided PHA values from the previous studies for comparison in this table. It should be noted that earthquake magnitude 6.5 was used in the previous studies for the entire study area.
24001006.001A/SAC23M158525_R2 Page 15 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Table 5
Probabilistic Peak Horizontal Acceleration and Controlling Earthquake Point ID
PHA (g) Deaggregation Results
(KLF, 2023) (DWR,
2015)
MW Distance (km)
Natomas NE 0.13 0.133 6.8 73
Natomas NW 0.14 0.144 6.8 65
Natomas West 0.15 0.160 6.7 58
Arcade Creek 0.13 0.139 6.8 72
Confluence 0.14 0.146 6.8 67
American River East 0.12 0.126 6.8 81
Little Pocket 0.14 0.152 6.7 63
Pocket 0.15 0.163 6.7 60
SREL South 0.15 0.148 6.7 62

CLOSING
This technical memorandum is for review by the subject project’s peer review panel for concurrence with the approach for the forthcoming Seismic Performance Summary Reports. This document is intended to be used as an appendix to the primary Seismic Performance Summary Report and is subject to the same limitations as in that report. If you have questions regarding this memorandum or if we may be of further assistance, please contact the undersigned.

Sincerely,
KLEINFELDER, INC.

Ryan Hochstatter, EIT Zia Zafir, PE, GE
Staff Geotechnical Engineer Sr. Principal Geotechnical Engineer

ATTACHMENTS
Figure 1 – Study Area
Figure 2 – Geologic Map
Figure 3 – Regional Faulting and Seismicity
Figure 4 – Seismic Source Model
Figure 5 – UCERF 3 Source Model Logic Tree
Attachment A1 – Significant Faults Included in Source Model Attachment A2 – Calculation Package – Shear Wave Velocity and Site Parameters 24001006.001A/SAC23M158525_R2 Page 16 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

Abrahamson, N.A., Silva, W.J., and Kamai, R. (2014). “Summary of the ASK14 Ground Motion Relation for Active Crustal Regions.” Earthquake Spectra, Vol. 30, No. 3, pp. 1025-1056.

Bozorgnia, Y. and Campbell, K. (2016). Ground Motion Model for the Vertical-to-Horizontal (V/H) Ratios of PGA, PGV, and Response Spectra. Earthquake Spectra, Volume 32, Issue 2, pp. 951-978.

Bryant, W., Sander, E., and Wills, C. (2007). Digital Database for Concord and Green Valley Faults. Final Technical Report prepared for the U.S. Geological Survey National Earthquake Hazards Reduction Program, USGS Award No. 05HQGR0029.

Building Seismic Safety Council (BSSC) (2014). United States Geological Survey (USGS) Earthquake Scenario Map, https://earthquake.usgs.gov/scenarios/catalog/, accessed July 2022.

California Department of Water Resources (2007). Technical Memorandum: Delta Risk Management Strategy (DRMS) Phase 1 Topical Area: Seismology Final. Prepared by URS Corporation and Jack R. Benjamin & Associates, Inc.

California Department of Water Resources (2012). Urban Levee Design Criteria.

Cornell, C.A. (1968). Engineering Seismic Risk Analysis, Bulletin of the Seismological Society of America, Vol. 58, No. 5.

Cornell, C.A. (1971). Probabilistic Analysis of Damage to Structures Under Seismic Loading, Dynamic Waves in Civil Engineering, London, Interscience.

Cramer, C., Toppozada, T, and Park, D. (1978). Seismicity of the Foothills Fault System Between Folsom and Oroville, California.

Field, E.H., Biasi, G.P., Bird, P., Dawson, T.E., Felzer, K.R., Jackson, D.D., Johnson, K.M., Jordan, T.H., Madden, C., Michael, A.J., Milner, K.R., Page, M.T., Parsons, T., Powers, P.M., Shaw, B.E., Thatcher, W.R., Weldon, R.J., II, and Zeng, Y. (2013). The Uniform California Earthquake Rupture 24001006.001A/SAC23M158525_R2 Page 17 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Forecast, Version 3 (UCERF 3), USGS Open File Report 2013-1165, CGS Special Report 228, Southern California Earthquake Center Publication 1792, http://pubs.usgs.gov/of/2013/1165/.

Fugro William Lettis Associates (FWLA 2010). “Surficial Geologic Map of the NEMDC East Study Area.” Scale 1:20,000. Dated 2010
Graymer, R., Jones, D., Brabb, E. (2002). "Geologic Map and Map Database of Northeastern San Francisco Bay Region, California: Most of Solano County and parts of Napa, Marin, Contra Costa, San Joaquin, Sacramento, Yolo, and Sonoma Counties". Miscellaneous Field Studies Map 2403.

Gülerce, Z. and Abrahamson, N.A. (2011). Site-Specific Design Spectra for Vertical Ground Motion, Earthquake Spectra 27(4), pages 1023-1047.

Gutenberg, B. and Richter, C.F. (1956). Earthquake Magnitude, Intensity, Energy and Acceleration, Bulletin of the Seismological Society of America, Vol. 46, No. 2.

Gutierrez, C. I. (2011). “Preliminary Geologic Map of the Sacramento 30’ x 60’ Quadrangle, California,” California Geological Survey, Preliminary Geologic Maps PGM-11-06 (1:100,000 scale).

Harden, D. R. (1998). “California Geology.” Published by Prentice Hall.

Humphreys, E., and Coblentz, D. (2007). North American Dynamics and Western U.S. Tectonics.

American Geophysical Union, Reviews of Geophysics, 45, RG3001.

Hoffman, R. (1992). Structural Geology of the Concord Area. American Association of Petroleum Geologists Pacific Section Annual Convention.

Idriss, I. M. (2014). “An NGA-West2 Empirical Model for Estimating the Horizontal Spectral Values Generated by Shallow Crustal Earthquakes.” Earthquake Spectra, Vol. 30, No. 3, pp. 1155-1177.

Jennings, C.W. and Bryant, W.A. (2010). Fault Activity Map of California. California Geologic Data Map Series Map No. 6.

Lienkaemper, J., Baldwin, J., Turner, R., Sickler, R., and Brown, J. (2013). A Record of Large Earthquakes during the Past Two Millennia on the Southern Green Valley Fault, California. Bulletin of the Seismological Society of America, Vol. 103, No. 4, pp. 2386-2403.

Merriam, M. (2012). Caltrans Fault Database V2a for ARS Online. Caltrans Fault Database V2 Report (http://dap3.dot.ca.gov/ARS_Online/technical.php)
Merz, H.L. and Cornell, C.A. (1973). Seismic Risk Analysis Based on a Quadratic Magnitude-Frequency Law, Bulletin of the Seismological Society of America, Vol. 63, No. 6.

Parrish, J. (2018). Faulting in California. California Geological Survey Map Sheet 54.

Powers, P.M. (2017). National Seismic Hazard Model Project Computer Code (NSHMP-HAZ) Software, https://doi.org/10.5066/F7ZW1K31.
24001006.001A/SAC23M158525_R2 Page 18 of 18 February 9, 2024 © 2024 Kleinfelder www.kleinfelder.com
KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Schwartz, D.P. and Coppersmith, K.J. (1984). Fault Behavior and Characteristic Earthquakes: Examples from the Wasatch and San Andreas Fault Zones, Journal of Geophysical Research, Vol. 89, pp. 5681-5698.

Stewart, J., Afshari, K., and Hashash, Y. (2014). Guidelines for Performing Hazard-Consistent OneDimensional Ground Response Analysis for Ground Motion Prediction. PEER Report 2014/16.

United States Army Corps of Engineers (USACE) (2016). ER 1110-2-1806 Earthquake Design and Evaluation for Civil Works Projects.

United States Geological Survey (USGS). Quaternary Fault and Fold Database for the United States, https://www.usgs.gov/natural-hazards/earthquake-hazards/faults, accessed October 2023.

Unruh, J. and Hector, S. (1999). Subsurface Characterization of the Potrero-Ryer Island Thrust System, Western Sacramento-San Joaquin Delta, Northern California.

Unruh, J. and Hitchcock, C. (2009). Characterization of Potential Seismic Sources in the Sacramento-San Joaquin Delta, California. Final Technical Report prepared for the U.S. Geological Survey National Earthquake Hazards Reduction Program. USGS Award No. 08HQGR0055.

Unruh, J., and Humphrey, J., 2017, Seismogenic Deformation Between the Sierran Microplate and Oregon Coast Block, California, USA. The Geological Society of America v. 45, no. 5, pp. 415-418 Unruh, J., Humphrey, J., and Barron, A., 2003, Transtensional Model for the Sierra Nevada Frontal Fault System, Eastern California. Geology v. 31, no. 3, pp. 327 – 330.

Wagner, D.L., Jennings, C.W., Bedrossian, T.L., and Bortugno, E.J. (1981). Geologic map of the Sacramento quadrangle, California, 1:250,000.

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Natomas NW
SREL South
Confluence
Natomas NE
Arcade Creek
Natomas West
Little Pocket
American River East

STUDY AREA
PROJECT:

FILE NAME:

FIGURE
1 DRAWN:

CHECKED BY:

DRAWN BY:
24001006.001A
SEP 2023
M. RYAN
K. HAGAN
F1_SiteMap.mxd
Explanation
!( Analysis Control Point
Levee Alignment
SACRAMENTO, CA FILE: \\azrgisstorp03\GIS_Projects\Client\SAFCA\24001006.001A-ULDC_groundmotion\F1_SiteMap.mxd KHagan 9/21/2023 0 3 6
Kilometers
Locations are Approximate £

SEISMIC EVALUATION GROUND MOTION

PARAMETER MEMORANDUM

ULDC & FEMA LEVEE CERTIFICATION PROJECT

SACRAMENTO AREA FLOOD CONTROL AGENCY

LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
Service Layer Credits: Source: Esri, Maxar, Earthstar
Geographics, and the GIS User Community; ESRI World
Imagery, Maxar Vivid Advanded image dates 4/12/2022,
4/26/2022, and 5/4/2022; SACOG Orthos image date
3/18/2022.

REGIONAL GEOLOGIC MAP
PROJECT:

FILE NAME:

FIGURE
2 DRAWN:

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K. HAGAN
F2_Geology.mxd
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Levee Alignment
SACRAMENTO, CA FILE: \\azrgisstorp03\GIS_Projects\Client\SAFCA\24001006.001A-ULDC_groundmotion\F2_Geology.mxd KHagan 9/21/2023 0 3 6
Kilometers
Wagner, D.L., C.W. Jennings, T.L. Bedrossian, and
E.J. Bortugno, 1981, Geologic Map of the
Sacramento Quadrangle, California, 1:250,000,
California Division of Mines and Geology Regional
Geologic Map Series, Map No. 1A.

Locations are Approximate £

SEISMIC EVALUATION GROUND MOTION

PARAMETER MEMORANDUM

ULDC & FEMA LEVEE CERTIFICATION PROJECT

SACRAMENTO AREA FLOOD CONTROL AGENCY

LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
#
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@ @ @ @
@ @ @ @
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@ @ @ Qmr
Qr
Qb
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Qm Modesto Formation
Riverbank Formation
Modesto-Riverbank Formations
Basin deposits
Levee and channel deposits
Historic displacement (< 150 years)
Mapped Fault Location
Dashed were Approximated
! ! ! ! Concealed
Holocene displacement (< 15,000 years)
Mapped Fault Location
Dashed were Approximated
! ! ! ! Concealed
Late Quaternary displacement (< 750,000 years)
Mapped Fault Location
Dashed were Approximated
! ! ! ! Concealed
Quaternary & unspecified displacement
(< 1,600,000 years)
undifferentiated Quaternary Well Constrained
undifferentiated Quaternary Moderately Constrained
! ! ! ! undifferentiated Quaternary Inferred
Pre-Quaternary geologic structures (CGS, 2010)
Mapped Fault Location
Dashed were Approximated
! ! ! ! Concealed
ANSS Earthquakes
Magnitude

4.0 - 4.9

4.9 - 5.9

5.9 - 6.9

6.9 - 7.9

7.9 - 8.9
125
Kilom
ete
r
R
a
diu
s
Project
Location Willows fault
Thornton Arch
Stockton fault
East Valley fault
West Valley fault
Capay fault
Sweitzer fault
West Napa fault
Chabot fault
Serra fault
Lagoon Valley fault
Black Butte fault
Round Valley fault zone
Williams fault
Miller Creek fault
Antioch fault
Corral Hollow fault
Hayward fault
Mohawk Valley fault
Rodgers Creek fault
Franklin fault
Dollar Point fault
Dog Valley fault
Clover Valley fault
Alexander fault
Greenville fault
Cross Spring fault
Spenceville fault
Soda Creek fault
Pilarcitos fault
Wildcat fault
Cordelia fault
Crosley fault
Pinole fault
Etsel Ridge fault
Mocho fault
Maacama fault
Maacama fault
Canada fault
Concord fault
Polaris fault
Calaveras fault
Rio Vista fault
Clayton fault
Mission fault
Giant Gap fault
Stoney Creek fault
Resort fault
Dunnigan Hills fault
Healdsburg fault
Bad Ridge fault
Pleasanton fault
Ione fault
Putah Creek
Cobb Mountain fault
Maidu East fault
Swain Ravine fault
Adobe Creek fault
Tolay fault
Green Springs Run fault
Chianti fault
Waters Peak fault
San Joaquin fault
Big Valley fault
Dewitt fault
San Jose fault
Poorman Gulch fault
San Andreas fault
Rescue fault
Seal Cove fault
Hunting fault
Bloomfield fault
Hot Springs Shear zone Vaca fault
Paynes Peak fault
Stanford fault
Youngs Creek fault
Corning fault
Vernalis fault
San Gregorio fault
Point Reyes fault
Midland fault
120°0'0"W
120°0'0"W
121°30'0"W
121°30'0"W
123°0'0"W
123°0'0"W
39°0'0"N
39°0'0"N
37°30'0"N
37°30'0"N
PROJECT NO:

CREATED:

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FIGURE
Quaternary Faults (Jennings and Bryant, 2010)
£
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ALeonard
F3_RegionalSeismic.mxd
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REGIONAL FAULTING

AND SEISMICITY
MRyan 3
0 20 40 80
Kilometers
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 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.

BASEMAP SOURCE:

Esri ArcGIS Online World Topography Map

SEISMIC EVALUATION GROUND MOTION

PARAMETER MEMORANDUM

ULDC & FEMA LEVEE CERTIFICATION PROJECT

SACRAMENTO AREA FLOOD CONTROL AGENCY

LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
24001006.001A
Seismic Responsibility Reach
Faults, National Seismic Hazard Map
(NSHM), 2014
normal
strike slip
thrust
unassigned
Levee Alignment
32 5 K ilom ete r R adius
Pacific
Ocean
Project
Location
Duck Flat fault
Great Valley 12
Great Valley 02
Deep Springs
Dry Mountain
Lost Hills
Fairview fault zone
Pittville 2011 CFM
Middlegate fault zone
Last Chance
Round Valley
West Napa 2011 CFM Great Valley 01
Antelope Valley 2011
Little Salmon (Offshore)
Airport Lake
Table Bluff
Greenville (No) 2011 CFM
Carson Range fault
Grass Valley fault zone
Zayante-Vergeles
West Tahoe
Hayward (So) 2011 CFM
Point Reyes 2011 CFM
Ortigalita (South)
Mohawk Valley 2011 CFM
Coaldale fault 1 Great Valley 07 (Orestimba)
Battle Creek 2011 CFM
Honey Lake 2011 CFM
Rainbow Mountain fault zone Independence rev 2011
Pyramid Lake fault zone Black Rock fault zone
Ione Valley fault
So Sierra Nevada
Hosgri
Russ 2011 CFM
Trinidad (alt1)
Rinconada 2011 CFM
Likely 2011 CFM
Buena Vista Valley fault zone Smith Valley fault
Eaton Roughs 2011 CFM
Hat Creek-McArthur-Mayfield
Owens Valley
White Mountains
Dixie Valley fault zone
Wassuk Range fault zone
San Andreas (Creeping Section) 2011 CFM
Mendocino
Reliz 2011 CFM
San Gregorio (North) 2011 CFM
San Andreas (Offshore) 2011 CFM
Bartlett Springs 2011 CFM
San Andreas (North Coast) 2011 CFM
Maacama 2011 CFM
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124°30'0"W
124°30'0"W
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Kilometers
BASEMAP SOURCE:

Esri ArcGIS Online World Topography Map
PROJECT NO:

CREATED:

CREATED BY:

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FILE NAME:

FIGURE
9/21/2023
KHagan
F4_SeismicSource.mxd

SEISMIC SOURCE MODEL
BASED ON UCERF3
MRyan 4 SEISMIC EVALUATION GROUND MOTION

PARAMETER MEMORANDUM

ULDC & FEMA LEVEE CERTIFICATION PROJECT

SACRAMENTO AREA FLOOD CONTROL AGENCY

LEVEE SYSTEMS

SACRAMENTO AND SUTTER COUNTIES, CALIFORNIA
24001006.001A
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 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.

SIGNIFICANT FAULTS INCLUDED IN SOURCE MODEL
___________________________________________________________________________________ Used in Used in Section
FM 3.1? FM 3.2? Mmax
3 Great Valley 03a Dunnigan Hills 27 20 3 6 TRUE TRUE 6.6 Great Valley 06 (Midland) 2011 CFM alt1 69 47 1 15 TRUE FALSE 7.3 Great Valley 04a Trout Creek 19 20 9 14 TRUE TRUE 6.6
Great Valley 03 Mysterious Ridge 51 20 9 14 TRUE TRUE 7.1 Great Valley 04b Gordon Valley 28 20 9 14 TRUE TRUE 6.8 Great Valley 06 Midland alt2 33 30 2 16 FALSE TRUE 7.2
Swain Ravine - Spenceville 103 60 0 12 TRUE TRUE 7.4
Great Valley 05 Pittsburg Kirby Hills alt2 32 90 10 20 FALSE TRUE 6.7 Great Valley 05 Pittsburg - Kirby Hills alt1 21 55 0 10.8 TRUE FALSE 6.6 Hunting Creek - Berryessa 2011 CFM 44 90 0 10.6 TRUE TRUE 6.9 Green Valley 2011 CFM 43 84 0 14 TRUE TRUE 7
Hunting Creek - Bartlett Springs connector 2011 38 90 0 12 TRUE TRUE 6.9 Los Medanos - Roe Island 21 39 0 14 TRUE TRUE 6.9
West Napa 2011 CFM 44 75 0 13.2 TRUE TRUE 7
Concord 2011 CFM 18 90 0 15 TRUE TRUE 6.6
Contra Costa (Lake Chabot) 2011 CFM 4 90 0 11.1 FALSE TRUE 5.9 Contra Costa Shear Zone (connector) 2011 CFM 30 81 0 12.9 TRUE FALSE 6.8 Clayton 16 90 0 16 TRUE TRUE 6.6
Contra Costa (Dillon Point) 2011 CFM 11 90 0 12.5 FALSE TRUE 6.3 Contra Costa (Vallejo) 2011 CFM 4 77 0 11 FALSE TRUE 5.8 Contra Costa (Ozal - Columbus) 2011 CFM 9 90 0 13.2 FALSE TRUE 6.3 Great Valley 02 22 15 7 9.6 TRUE TRUE 6.5
Franklin 2011 CFM 38 90 0 13.2 TRUE TRUE 6.9
Contra Costa (Southampton) 2011 CFM 11 80 0 14 FALSE TRUE 6.4 Contra Costa (Briones) 2011 CFM 9 90 0 12.9 FALSE TRUE 6.3 Greenville (No) 2011 CFM 51 84 0 14.9 TRUE TRUE 7.1
Collayami 2011 CFM 35 90 0 10 TRUE TRUE 6.7
Contra Costa (Larkey) 2011 CFM 8 90 0 15 FALSE TRUE 6.3 Contra Costa (Reliez Valley) 2011 CFM 6 90 0 14.7 FALSE TRUE 6.1 Bennett Valley 2011 CFM 33 90 0 10 TRUE TRUE 6.7
Mount Diablo Thrust North CFM 19 40 1 13.5 TRUE FALSE 6.8 Contra Costa (Lafayette) 2011 CFM 8 90 0 14.6 TRUE TRUE 6.3 Rodgers Creek - Healdsburg 2011 CFM 82 77 0 12 TRUE TRUE 7.3 Mount Diablo Thrust 25 38 8 16 FALSE TRUE 6.7
Hayward (No) 2011 CFM 53 82 0 11.1 TRUE TRUE 7
Bartlett Springs 2011 CFM 164 90 0 14.5 TRUE TRUE 7.6
Calaveras (No) 2011 CFM 48 80 0 14 TRUE TRUE 7
Maacama 2011 CFM 175 63 0 10.9 TRUE TRUE 7.6
Great Valley 07 (Orestimba) 66 20 7 9.6 TRUE TRUE 7
Great Valley 01 44 15 7 9.6 TRUE TRUE 6.8
Mount Diablo Thrust South 11 40 1 13.5 TRUE FALSE 6.5
Hayward (So) 2011 CFM 54 76 0 13.4 TRUE TRUE 7.1
San Andreas (North Coast) 2011 CFM 171 90 0 11 TRUE TRUE 7.5 FAULT SECTION ID Length
(km)
Ave Dip
(Deg)
Upper Seis.

Depth (km)
Lower Seis.

Depth (km)
24001006.001A/SAC23M158525_R2 February 9, 2024
© 2024 Kleinfelder www.kleinfelder.com
ATTACHMENT A2
CALCULATION PACKAGE – SHEAR WAVE VELOCITY AND SITE PARAMETERS ___________________________________________________________________________________ Project Name: SACFA ULDC/FEMA
Project Number: 24001006.001A
Revision History:

Version Analyzed By Date Reviewed By Date
0 M. Ryan 9/13/2023 Zia Zafir 9/14/2023
References:

Initial Evaluation
Purpose:

Analysis Type:

Site specific seismic hazard analysis for SAFCA ULDC/FEMA levee certification HAZ for PSHA
Notes
See Report and updated model sheet for results
Site characterization only in this sheet
KLF No. 24001006.001A
Latitude 36.652563
Longitude -121.811094
Background Information:

Summary:

Site-Specific Site Characteristics
Vs30 (m/s) Z1 (m) 1
Z2.5 (km) 2
335 0.428 1.55
Notes

1. Per Abrahamson-et al (2014) NGA West 2

2. Per Campbell-Bozorgnia (2014) NGA West 2
Vs30 estimated for stiff soils, typically occuring at depth of about 100 to 120ft below ground surface; consistent with analysis by URS for previous certification in 2007
Z1.0 and Z2.5 considered using NGA W2 relationships - justification per Petersen et al. 2019 NGA W2
(HAZ code uses Z1.0 and Z2.5 in km,
values used shown above)
24001006.001A/SAC24R164096_R1 Page C-1 February 12, 2024 © 2024 Kleinfelder (Revised September 10, 2024)

APPENDIX C
SECTION 6, SEISMIC ANALYSIS, GUIDANCE DOCUMENT FOR GEOTECHNICAL ANALYSES, URBAN LEVEE

EVALUATIONS PROJECT
_____________________________________________________________________

GUIDANCE DOCUMENT
for Geotechnical Analyses
Urban Levee Evaluations Project
Contract 4600008101
April 2015
Prepared for:

DEPARTMENT OF WATER RESOURCES
Division of Flood Management
3464 El Camino Avenue, Suite 200
Sacramento, CA 95821
Prepared by:
2870 Gateway Oaks Drive, Suite 150
Sacramento, CA 95833
SECTION 6.0 SEISMIC ANALYSIS

6.0 SEISMIC ANALYSIS
The simplified screening-level seismic vulnerability assessment procedures presented in this section were developed specifically for the geologic and seismic conditions of ULE study areas. This procedure may not apply to other regions where geology, levee configurations, or intensity and durations of shaking differ from ULE study areas. A large number of abbreviated terms are used in this seismic analysis section. See the list of acronyms and abbreviations in the Table of Contents for definitions of terms.

This section presents general guidelines for performing a screening-level seismic vulnerability analysis for levees in the Sacramento and San Joaquin river systems.

Guidelines are presented for performing soil liquefaction triggering analysis, post-seismic slope stability analysis, and, as necessary, seismic deformation analyses and using the results from these analyses to then assign a seismic vulnerability class to each levee segment, or part thereof, in a study region.

ULE analysts should perform seismic vulnerability analyses using a 200-year return period seismic event and the higher of either the average summer or winter WSE. The flow chart shown in Figure 6-1 illustrates the general process for performing seismic vulnerability analyses for ULE intermittently-loaded levees. Intermittently-loaded levees are defined in ULDC1 (DWR, 2012) as levees that do not experience a water surface elevation of 1 foot or higher above the elevation of the landside levee toe at least once a day for more than 36 days per year on average. Intermittently-loaded levees have been identified as being present in the Urban study areas and the liquefaction triggering analyses and seismic vulnerability analyses results for these levees will be presented in each study area’s GER in Volume 2.

The purpose of the seismic vulnerability analysis is to estimate vertical deformation, which is then used to assign a seismic vulnerability class to a seismic segment (Table 6-1). The seismic segment(s) and analysis cross section(s) should be selected based on liquefaction triggering analysis results, available topography and bathymetry, distance to river/channel, levee geometry, and existing and/or planned mitigation measures. The seismic vulnerability analysis sections representing levee segments with potential liquefaction may be selected independent of reaches evaluated for static conditions and could be representative of multiple reaches or segments.

For levee segments assessed as having liquefiable layers, two conditions may exist: the segment may meet all static ULE criteria, or the segment may require one or more static remedial alternatives. For those segments meeting all static ULE criteria, ULE analysts should perform a seismic vulnerability analysis as described in this section under existing conditions for the segment. For those segments requiring one or more static remedial alternatives, those alternatives must meet ULE criteria, and will be verified and assumed to be in place prior to performing seismic vulnerability analysis. ULE analysts should then perform seismic vulnerability analyses under applicable static conditions (i.e., either existing conditions, or ULE’s selected static remedial alternative). 1 See Appendix C for the Urban Levee Design Criteria (ULDC) (DWR, 2012). 20150427_GuidanceDoc.docx 6-1 Issue Date: April 2015

SECTION 6.0 SEISMIC ANALYSIS
For the frequently-loaded levees which are present in several Urban-Non-Project study areas, ULE analysts should use the guidance defined in ULDC (DWR, 2012) Sections 7.6 and 7.7.2, and the protocol presented in Section 6.11 will be followed. The seismic vulnerability evaluation will be performed under existing conditions and presented in Volume 1 of the GERs. For frequently-loaded levee segments that do not meet seismic vulnerability criteria, seismic remedial alternatives will be identified, evaluated, costed, and presented in Volume 2 of the GERs. Remediation for seismic vulnerability is only performed for frequentlyloaded levees.

The overall methodology for seismic evaluations is based on a study by the Seismic Evaluation and Methodology Group as described in the Levee Seismic Vulnerability Assessment Methodology Report (URS, 2008). It is also based on subsequent recommendations from the ICB and seismic panel members (ICB, 2013; Balakrishnan and Perlea, 2013), respectively.

ULE seismic vulnerability assessments are based on empirical procedures developed for a screening-level evaluation. Future protocols, if necessary, for the design and implementation of any seismic remedial alternative should be based on more detailed site investigation, site characterization, and site-specific analytical procedures. Such additional studies should more precisely define the extent of mitigation required, and should reduce the scope and cost of mitigation. Additional site characterization and analyses may indicate remedial alternatives are not required.

6.1 Seismic Analysis Objective
The objectives of the seismic screening analyses are to:
 Evaluate, under existing conditions, the potential for liquefaction of the levee and/or the underlying foundation materials during a 200-year return period seismic event  Identify soft soils2 in the levee and/or the underlying foundation materials  Prepare longitudinal profiles of potentially liquefiable layers  Select levee segment boundaries for seismic vulnerability analysis  Identify and develop representative cross sections for seismic vulnerability assessments  Perform post-earthquake static and pseudo-static slope stability analyses  Evaluate seismically-induced deformation and resulting freeboard loss at the levee crown. Note that ULE analysts will make this assessment under existing conditions if no static remedial alternative(s) are needed, or will make the assessment with the selected static remedial alternative in place.
2 For ULE screening level seismic evaluation, soft soil is defined as a non-free-draining soil with estimated shear strength of less than 500 psf. This is not the same as “soft” soil defined for static stability analyses in Section 5.9.4
20150427_GuidanceDoc.docx 6-2 Issue Date: April 2015

SECTION 6.0 SEISMIC ANALYSIS
 Based on the amount of freeboard loss due to seismic deformation, categorize the relative seismic vulnerability of levee segments using a three-tiered system, as defined in Table 6-1. The three vulnerability classes are:
− Low vulnerability
− Medium vulnerability
− High vulnerability
 For frequently-loaded levees only, if a high vulnerability categorization is identified, then the additional efforts defined in Section 6.11 will be implemented.

6.2 WSE Conditions
ULE analysts should evaluate the seismic performance of levees along river systems using the higher of either the average summer or winter WSE when assessing liquefaction evaluation, seismic slope stability, and slope deformation. For levees along bypasses, or in other locations where water is not always present, the WSE should be set based on an evaluation of WSEs in adjacent segments, or groundwater levels. In the absence of such data, ULE analysts should use the WSE at either the waterside or landside levee toe elevation, based on engineering judgment.

For frequently-loaded levees, ULE analysts should use the WSE that is the mean high tide level on the waterside and the higher of either the winter or summer WSE on the landside.

Note that boring and CPT data used during liquefaction triggering analyses are corrected for groundwater depth at the time of exploration.

ULE analysts should consult with the Regional Technical Lead and ULE Task Order Manager when selecting WSEs along bypasses or at other locations where WSE information is not available.

6.3 Seismic Loading Conditions
ULE analysts should assess liquefaction and subsequent seismic vulnerability for one seismic loading condition: a 200-year return period seismic event. Figure 6-2 shows the peak horizontal acceleration (PHA) contours for ULE study areas under stiff soil conditions (i.e., shear wave velocity Vs,30 of 335 meter/second). The PHAs shown in Figure 6-2 correspond to 200year levels of peak horizontal acceleration that would occur on relatively stiff soils at depths typically on the order of 100 feet to 120 feet throughout ULE study areas (URS, 2012). Appendix K presents more background information and a discussion how Figure 6-2 was developed.

Amplification of these acceleration levels as they propagate upward through shallower foundation soils of lesser stiffness, and interactions of levee embankments with these motions, is addressed by representative analyses of two-dimensional dynamic response models that include both levees and foundation soils. The computer program QUAD4M was used to perform two-dimensional site response analyses. 20150427_GuidanceDoc.docx 6-3 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS

6.4 Criteria
ULE seismic vulnerability criteria for intermittently-loaded levees, summarized in Table 6-1, and frequently-loaded levees, summarized in Table 6-6, are based on a levee’s postseismic-event flood protection ability. Seismic vulnerability is estimated based on:
 The estimated amount of vertical deformation relative to landside levee height  Potential damage to internal structures (e.g., cutoff walls, etc.)  Potential for cracking of the levee embankment
 Remaining freeboard (10-year WSE +3 feet) after seismic deformation Table 6-1 Criteria for Seismic Vulnerability of Intermittently-Loaded Levees Amount of Crown2
Displacement Relative to
Landside Levee Height
(percent)
Potential for
Significant Damage to
Internal Structures
(e.g., Cutoff Walls)
Remaining Freeboard 2
for Post Seismic
Evaluation (10-Year
Flood WSE +3 feet) 3
Vulnerability
Class4
(PostSeismic Flood
Protection Ability)
< 10 No >0.3 m (1 foot) Low Vulnerability
<20 Possibly Between 0 and >0.3 m (1 foot) Medium Vulnerability ≥20
(Flow Slide Condition)
Yes None High Vulnerability
Note:
1 This table applies to intermittently-loaded levees. See Section 6.11 for information about frequently-loaded levees. 2 Vertical crown displacements can be estimated at 0.7 times the deviatoric deformation from simplified deformation analysis (such as Newmark type displacement), and by adding volumetric displacement as applicable. 3 Based on ULDC criteria for intermittently-loaded levees (Section 7.7.1 of ULDC [DWR, 2012]). 4 Analyses results must pass each of the criteria in the first three columns of the table at a given vulnerability class (the last column), or the corresponding segment should be rated at the next higher vulnerability class.

Although a segment’s seismic vulnerability class will be documented in each study area’s GER Volume 2, no seismic remedial alternative or associated cost will be established in the GER for what ULDC defines as intermittently-loaded levees. See Section 6.11 of this Guidance Document and Sections 7.6 and 7.7.2 of ULDC for seismic assessment of frequently-loaded levees.

6.5 Software

6.5.1 Liquefaction Potential
Two Microsoft Excel liquefaction-triggering analysis spreadsheets were developed for ULE.

The two spreadsheets are for SPT-based and CPT-based liquefaction triggering analyses, and correspond to the methodologies described in Section 6.7. Examples of the spreadsheets are in Appendix J.

When assessing liquefaction, ULE analysts should be aware that the CPT-based liquefaction spreadsheet may classify some fine-grained soils as liquefiable. In such cases, additional information regarding soil properties, including SPT blow counts within the same layer, Atterberg limits and moisture content test results (Section 6.7.1), are required to screen CPTbased liquefaction assessment results. This screening can be difficult and uncertain, as 1 20150427_GuidanceDoc.docx 6-4 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS
such, ULE analysts should place more emphasis on SPT interpretations and material classification from laboratory test data. Therefore, SPT borings drilled under ULE should be selected as the primary source of data for liquefaction analyses. CPT and historical boring data should be considered a secondary data source, and should be used primarily to support evaluation of the longitudinal extents of liquefaction potential (Section 6.7.3).

Given the caveats described above, CPT data can be used to:
 Extrapolate the continuity of liquefiable strata based on engineering judgment and SPT liquefaction triggering analysis results at selected locations.  Identify zones as non-liquefiable that have high CPT tip resistance.  Perform liquefaction triggering analyses if no SPT data are available or if SPT data are limited.

6.5.2 Slope Stability Analyses
ULE analysts should perform seismic slope stability analyses using SLOPE/W (2007 and later versions), which is a two-dimensional limit equilibrium slope stability analysis software program developed by GEO-SLOPE International Ltd. (http://www.geoslope.com). ULE analysts should use the Spencer’s Method approach, which satisfies both moment equilibrium and force equilibrium, for all slope stability analyses. ULE analysts may consider using other slope stability analysis software, including UTEXAS4, upon approval of DWR’s Task Order Managers.

6.6 Analysis Approach
The overall methodology for seismic evaluation is based on the study presented in the Levee Seismic Vulnerability Assessment Methodology Report (URS, 2008). In essence, liquefaction triggering and seismic vulnerability assessment are based primarily on six types of data or information:
 200-Year PHA hazard map (Figure 6-2)
 Cyclic shear stress (Ƭmax) charts (Figure 6-3)
 Recommended Kmax vs. Input Motion PHA (Figure 6-4)
 Yield acceleration (Ky) estimation (Section 6.8.4)
 Recommended Newmark Displacement vs. Ky/Kmax relationship (Figure 6-5)  Seismic vulnerability classification (Table 6-1)
The following sections describe the procedures for using these six types of information to perform screening-level assessments of liquefaction and seismic vulnerability.

6.7 Liquefaction Triggering Analyses
Liquefaction triggering analyses evaluate whether or not the levee and/or the underlying foundation materials could be susceptible to liquefaction during a 200-year return period seismic event. In some cases, liquefaction triggering analyses results will also be used to estimate the post-seismic strengths of materials for use in seismic slope stability analysis. 20150427_GuidanceDoc.docx 6-5 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS
ULE analysts should implement the following process to assess liquefaction potential (Figure 66).

6.7.1 Perform Liquefaction Potential Assessment
For the purpose of ULE, levee soils located at certain depths are not considered critical for seismic performance, and can be removed from liquefaction potential analysis. ULE analysts should use the following criteria to identify the depth of soils that are not located within the vertical liquefaction assessment zone for ULE:
 All unsaturated soils located above the analysis WSE defined in Section 6.2, and  All soils located below the greater of the following depths:
− 50 feet below the landside levee toe,
− Two times the levee height (measured at landside) below the landside levee toe, or − Bottom of the river channel.

If the soil layer susceptible to liquefaction continues below the bottom of the evaluation depth, the full depth of the liquefiable layer will be evaluated.

In the vertical liquefaction assessment zone, analysts can then screen out soils not susceptible to liquefaction based on the following criteria3 :
 All soils with (N1)60-cs ≥ 23 or qC,1mod ≥ 10 MPa or 100 tsf  All soils classified as CH or MH
 For intermittently-loaded levees, all soils classified as CL, as well as soils classified as ML with any of the following:
− Plasticity Index ≥ 10 (See Figure 6-7)
− Liquid Limit ≥ 35
− Water Content ≤ 0.8 x (Liquid Limit)4
 For frequently-loaded levees, soils classified as CL or ML with any of the following:
− Plasticity Index ≥ 10 (See Figure 6-7)
− Liquid Limit ≥ 35
− Water Content ≤ 0.8 x (Liquid Limit)4
 Compacted, fine-grained soils used for remedial alternatives described in each study area’s GER Volume 2
 Clayey sand (SC) with greater than 20 percent fines
3 See the list of Acronyms and Abbreviations in the Table of Contents for definitions of terms used here. 4 The water content for comparison with liquid limit should be the saturated water content. There is a potential for the water content of soil samples collected in the field to be lower than that at the time of a seismic event. Analysts should consider this during their assessment and apply engineering judgment as necessary.
20150427_GuidanceDoc.docx 6-6 Issue Date: April 2015

SECTION 6.0 SEISMIC ANALYSIS
Atterberg limits and water content tests are very important in the evaluation of liquefaction susceptibility of fine-grained soils. Accurate field and laboratory classification of ML, CL and CL-ML soils can be very difficult and high quality Atterberg limit testing should be implemented to support, and as appropriate, override field classification in any design level seismic analyses.

In the absence of Atterberg limits test results for a fine-grained layer in this screening study, ULE analysts should use engineering judgment when considering fines contents and the nature of the fines. In general, soils field-classified as CL, CH, or MH can be considered unlikely to liquefy, but soils field-classified as ML or CL-ML should be considered potentially liquefiable, depending on the reported density.

If, based on the above criteria, the levee embankment and/or foundation materials are not considered susceptible to liquefaction and are not soft soils5 the materials may be classified as non-liquefiable, irrespective of earthquake loading. Soils not meeting the above criteria should be considered susceptible to liquefaction and should be assessed using the analyses discussed in Section 6.7.2.

The next step is to identify representative exploration locations and data for liquefaction triggering assessment. ULE analysts should review soil boring and CPT data and select an appropriate number of explorations for analysis to assess the liquefaction potential in the study area. For example, if the stratigraphy in a segment is generally uniform in terms of soil types and properties, one or two exploration locations may be sufficient for assessment.

Analysts should consider both toe and crown explorations.

ULE analysts should use the geologic plans and profiles for a GER study area to help select the number and location of explorations for analysis. Once ULE analysts have identified explorations for liquefaction triggering analysis, analysts should consult with the Regional Technical Lead and ULE Task Order Manager prior to performing analysis for the selected explorations.

6.7.2 Perform Liquefaction Potential Analyses
As noted, two Microsoft Excel liquefaction triggering spreadsheets (one SPT-based and one CPT-based) have been developed for use during ULE-wide evaluation of liquefaction potential and are based on the project-specific methodology developed for ULE. The SPTbased liquefaction spreadsheet was developed in accordance with the procedure recommended by Cetin et al. (2004). The CPT-based liquefaction spreadsheet was developed in accordance with the procedure recommended by Moss et al. (2006). The CPTbased correlations of Moss et al. (2006) are compatible with the SPT-based method Cetin et al. (2004). Examples of these spreadsheets are in Appendix J.

The spreadsheets calculate the factor of safety against liquefaction (FSL), which is equal to the ratio of the cyclic resistance ratio (CRR) to the cyclic stress ratio (CSR). Required parameters for input to calculate the cyclic stress ratio are:
5 For ULE screening level seismic analyses, soft soil is defined as a non-free-draining soil with estimated shear strength of less than 500 psf. This is not the same as “soft” soil defined for static stability analysis in Section 5.9.4.
20150427_GuidanceDoc.docx 6-7 Issue Date: April 2015

SECTION 6.0 SEISMIC ANALYSIS
 PHA
 Maximum shear stress (Ƭmax)
6 , which is embedded in the spreadsheet
 Effective overburden stress (σ′v) at the analyses WSE (i.e., the higher of either the winter or summer average)
 Location (crown, landside, or waterside)
Figure 6-2 shows the PHA contours for ULE study areas for a stiff soil condition (Vs,30=335 m/s).

The cyclic shear stress (Ƭmax) values, embedded in the ULE liquefaction triggering spreadsheets, are based on two-dimensional site response analyses developed for three general locations along a levee cross section: the waterside toe, the center of crown, and the landside toe. As documented in the Levee Seismic Vulnerability Assessment Methodology Report (URS, 2008), a range of ground motions for a stiff soil condition (Vs,30=335 m/s) was applied to the base of a two-dimensional cross section profile of representative levees and foundation soil conditions approximately 120 feet deep. The two-dimensional site response analyses calculated sitedependent amplification of the input motions based on the effects of the overlying stratigraphy and the topography of the levee embankments.

These two-dimensional site response analyses were performed with a WSE 10 feet below the crown elevation and with a straight line phreatic surface to the landside toe of the levee.

Considering these WSEs may be higher than the seismic analysis WSEs in many ULE study areas, ULE analysts should calculate CSR values using cyclic shear stress (Ƭmax) values from the two-dimensional site response analyses and site-specific effective overburden stress (σ′v) corresponding to the analysis WSE. The representative CSR values are calculated in the liquefaction triggering spreadsheet using the following equation:

CSR = 0.65 x Ƭmax / σ′v
Charts of cyclic shear stress values (Ƭmax) for each of the three locations are shown in Figure 6-3. These charts are also built into the SPT and CPT liquefaction evaluation spreadsheets to calculate cyclic stress values once the PHA and location are entered into the spreadsheets.

As shown in Figure 6-4, for borings or CPTs waterward of a point one-third up the waterside slope of the levee, ULE analysts should use waterside curves. For borings or CPTs located landward of a point one-third up the landside slope of the levee, ULE analysts should use the landside curves. For borings or CPTs one-third up the waterside and landside slopes, or on the levee’s crown, ULE analysts should use the curves for the levee crown.

Cyclic resistance ratio values (see Figure 6-8) are calculated based on corrected blow counts (N1)60 for SPT analyses (fines correction in the liquefaction triggering analysis is applied in the CRR equation and capped at 35 percent fines content as per Cetin et al., 2004) and on tip resistance (qc), sleeve friction (fs), and friction ratio (Rf) for CPT analyses.

Additional information used in the analyses includes USCS classifications, unit weights, 6 Ƭmax is defined for the ULE process as the peak cyclic shear stress and varies with location and depth, and, as noted, is embedded in the liquefaction triggering spreadsheets. 20150427_GuidanceDoc.docx 6-8 Issue Date: April 2015

SECTION 6.0 SEISMIC ANALYSIS
water contents, Atterberg limits data, groundwater depth at the time of the exploration, earthquake magnitude (MW), etc. In the absence of fines content data, ULE analysts should be aware that the SPT-based spreadsheet assumes fines contents based on USCS classifications and that entry of non-USCS classifications may result in erroneous liquefaction triggering calculations. Both spreadsheets provide the analyst with the option of assigning layers as non-liquefiable based on Atterberg limits data and/or soil type and the criteria outlined in Section 6.7.1. For the purpose of ULE, analysts should assume an Mw of

6.5 associated with the 200-year event. This magnitude was selected based on deaggregation of the earthquake sources considered in the probabilistic seismic hazard assessment (URS, 2012).

In some cases, groundwater data may not be available at the time the exploration was performed. For these cases, ULE analysts should use data from nearby explorations performed during a similar time of year or, when such data are unavailable, the average summer or winter WSE based on the date of the exploration.

In the absence of laboratory unit weight data (for use in the SPT-based spreadsheet), ULE analysts should determine unit weights based on soil types and N60 values as shown in Table 6-2.

Table 6-2 Unit Weights for Liquefaction Assessment
Soil Type N60 Unit Weight (pcf)
Clays and silts ≤ 4 115
5 to 8 120
≥ 9 125
Sands ≤ 10 115
11 to 29 125
≥ 30 130
Gravels All 130
Based on the spreadsheet analysis results, ULE analysts should use the following criteria to classify a soil layer, or vertical portion of a soil layer, as having liquefaction potential:
 If all FSL assessment values for a particular layer are equal to or greater than 1.25, the soil layer may be classified as non-liquefiable.
 If all FSL assessment values for a particular layer are equal to or less than 1.0, the soil layer may be classified as likely liquefiable.
 If the FSL assessment values are between 1.0 and 1.25, the soil layer may be classified as less likely liquefiable. If these less likely liquefiable layers are present in isolation in a non-liquefiable zone, the need for further evaluation will be assessed during the seismic vulnerability process.
 If the FSL assessment values for a particular layer are mixed and include multiple values less than 1.0, then the layer should be considered likely liquefiable, unless the layer can be logically split into sub-layers. ULE analysts should not perform this assessment in isolation; rather an assessment of the liquefaction profile should be performed to evaluate continuity of the layer.
20150427_GuidanceDoc.docx 6-9 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS
As discussed in Section 6.5.1, when assessing liquefaction, ULE analysts should be aware that the CPT-based liquefaction spreadsheet may classify some fine-grained soils as liquefiable. In such cases, additional information regarding soil properties, including SPT blow counts within the same layer, Atterberg limits and moisture content test results (Section 6.7.1), are required to screen CPT-based liquefaction assessment results. This screening can be difficult and uncertain, and as such, more emphasis should be placed on SPT interpretations and material classification from laboratory test data. Therefore, SPT borings drilled under ULE should be selected as the primary source of data to be carried into the liquefaction triggering analyses. CPTs and historical borings should be considered a secondary data source and used primarily to support evaluation of the longitudinal extents of liquefaction potential (Section 6.7.3).

6.7.3 Evaluate and Document Longitudinal Extent of Potentially Liquefiable Layers
Use of reach boundaries established for static analysis (seepage, slope stability) are not always appropriate for seismic vulnerability assessment. Consequently, assessment of seismic vulnerability will use the term “segments.” ULE analysts will establish segments by reviewing liquefaction analysis results, topography and bathymetry, distance to river/channel, and existing and/or planned remedial alternatives. A segment may be a portion of a reach or may be composed of multiple reaches.

After analyzing the liquefaction potential of the selected explorations, ULE analysts should establish the longitudinal and lateral extents of likely and less likely liquefiable layers for the study area by evaluating the liquefaction analyses results for the selected explorations and the geologic plans and profiles. ULE analysts should make an assessment of the longitudinal extents of liquefiable layers based on the results of analyses described in Sections 6.7.1 and

6.7.2. Additionally, ULE analysts should consider any other relevant site information. The beginning and end points of likely and less likely liquefiable layers should extend to explorations determined to be non-liquefiable.

Liquefaction analysis results for the selected explorations can be used in multiple segments to establish the longitudinal extents of likely and less likely liquefiable layers. The longitudinal extents of liquefiable zones may extend into adjacent segments and/or affect only a portion of a segment.

6.8 Seismic Vulnerability Analyses

6.8.1 Overview
The purpose of the seismic vulnerability analysis is to estimate vertical deformation, which is then used to assign a seismic vulnerability class to a seismic segment (Table 6-1). The seismic segment(s) and analysis cross section(s) should be selected based on liquefaction analysis results, available topography and bathymetry, distance to river/channel, levee geometry, and existing and/or planned mitigation measures. The seismic vulnerability analysis sections representing levee segments with potential liquefaction may be selected independent of reaches evaluated for static conditions and could be representative of multiple reaches or segments.
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Levee segments that have been identified to have potentially liquefiable soils and/or soft soils7 will be candidates for seismic vulnerability analysis. However, the seismic vulnerability analysis will only be performed using a statically-resistant levee configuration. A levee reach is considered statically-resistant if it satisfies one of the following criteria:
 The reach meets all static analyses criteria under existing conditions (i.e., no static remediation is required).
 The reach is remediated for static vulnerability based on GER Volume 1 results. Note that conceptual static remedial alternatives must be implemented if the reach does not meet all static analyses criteria. The selected static remedial alternative will be assumed to be in place for seismic vulnerability analyses.

For seismic vulnerability analyses, ULE analysts should evaluate both waterside and landside slopes with circular and wedge-shaped failure modes using the search routines available in the slope stability software. Potential deep and shallow failure surfaces should also be evaluated. For seismic deformation analyses (Section 6.8.4), the pseudo-static horizontal seismic coefficient K or Ky should be applied only in the horizontal direction.

After selecting the analysis sections for seismic vulnerability analyses, ULE analysts should implement the following steps (see Figure 6-1):
 Perform a post-seismic slope stability analysis (Section 6.8.3) using shear strengths as discussed in Section 6.8.2. The calculated factor of safety, denoted as FSPS, can then be used to assess whether the segment is unstable after the earthquake. If the FSPS is less than 1.0, then the levee segment is classified as having high vulnerability (see Table 6-1), and no seismic deformation analysis is required.  If FSPS is greater than 1.3, the section is classified as having low vulnerability, and no seismic deformation analysis is required.
 For seismic analysis cross sections not meeting the conditions stated above, seismic deformation analysis will be performed to identify the appropriate seismic vulnerability class.

6.8.2 Seismic Shear Strengths
Seismic loading is considered a rapid loading condition; for these ULE screening-level evaluations, shear strengths for post-seismic slope stability and seismic deformation analyses should be modeled as described below. Modeling of tension cracks is also discussed at the end of this section.

If statically remediated levee geometries are analyzed, strengths will be evaluated assuming full consolidation has occurred under the remediated geometry (i.e., conditions for an earthquake relatively soon after construction will not be evaluated). For final design, evaluation of end-of-construction conditions must be completed and consolidation time must 7 For ULE screening level seismic analyses, soft soil is defined as a non-free-draining soil with estimated shear strength of less than 500 psf. This is not the same as “soft” soil defined for static stability analyses in Section 5.9.4
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be assessed to evaluate the likelihood of a seismic event occurring before primary consolidation is complete. This is particularly relevant to areas with thick clayey deposits.

6.8.2.1 Likely Liquefiable Soils with FSL ≤ 1
When saturated, loose coarse-grained and fine-grained materials are expected to contract and generate positive pore pressures during shear. During rapid seismic loading, the rate of pore pressure generation typically exceeds the rate of pore pressure dissipation, resulting in an incremental increase in pore pressures in these materials. This pore pressure increase leads to shear strength degradation that may ultimately lead to liquefaction or cyclic mobility.

Soils identified as likely liquefiable should be modeled using the post-liquefaction residual undrained shear strength. Residual undrained shear strengths should be estimated using the correlation proposed by Seed and Harder (1990), as shown on Figure 69. ULE analysts should use the strength at a point lying one third of the distance from the lower-bound curve to the upper-bound curve in Figure 6-9. To use Figure 6-9, residual undrained strength should be estimated based on (N1)60-cs-Sur values of the likely liquefiable layer(s). Plots of (N1)60-cs-Sur should be prepared for the seismic segments and median (N1)60-cs-Sur values should be used in the estimation of residual undrained strength.

Both the Cetin et. al. (2004) procedure for liquefaction triggering analysis and the Seed and Harder (1990) procedure for residual undrained strength estimation are empirical methods.

The fines correction for the (N1)60csSur values used in the Seed and Harder (1990) residual undrained strength correlation is not the same as the fines correction used in the liquefaction triggering analysis. As noted above, fines correction in the liquefaction triggering analysis is applied in the CRR equation as per Cetin et. al. (2004) and capped at 35 percent fines content. However, once a soil layer is considered as likely liquefiable, the fines correction is applied as per the Seed and Harder (1990) procedure. The (N1)60-cs-Sur values used in Figure 6-9 should be calculated based on the fines corrections (ΔNcorr) in Table 6-3 or Table 6-4 and the following equation:
(N1)60-cs-Sur = (N1)60 + ΔNcorr
Table 6-3 ΔNcorr Values Based on Fines Content.

Percent Fines ΔNcorr
0-5% 0
6-15% 1
16-30% 2
31-40% 3
41-60% 4
61-100% 5
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Table 6-4 ΔNcorr Values Based on USCS Classification
USCS ΔNcorr
SP, SW, GP, GW 0
All Other Sands & Gravels 1
SC 2
ML 4
CL-ML 5
Note: Values based on suggested fines contents in USACE ETL 1110-2-580 (Draft), Table C-1.

To evaluate the residual undrained strength of coarse-grained and sand-like materials from CPT data, ULE analysts should convert CPT tip resistance to an equivalent (N1)60-cs-Sur value.

Based on a comparison between liquefaction triggering criteria from SPT data (Seed et al., 2003) and from CPT data (Moss et al., 2006), the following relationship has been developed for use in these screening evaluations:
(N1)60-cs-Sur ≈ qc,1,mod (tsf)/4.2
where the tip resistance has been corrected for increasing fines content and plasticity as:
qc,1,mod = qc,1 + Δqc
where qc,1 is the normalized tip resistance and Δqc is a “fines” correction factor as recommended in Moss et al. (2006). Δqc is a function of CSR and Rf and calculated in the ULE Excel spreadsheet using CPT data (Appendix J). The above correlation compares well with other relationships published in the literature (e.g., Robertson and Campanella, 1983; Kulhawy and Mayne, 1990).

6.8.2.2 Less Likely Liquefiable Soils with 1.0 < FSL < 1.25 As discussed in Section 6.7.2, ULE analysts should use engineering judgment to classify layers as likely liquefiable, less likely liquefiable, or non-liquefiable. This assessment should not be performed in isolation; rather, an assessment of the longitudinal geologic profile should be considered to evaluate continuity of the layer. Isolated blow counts resulting in 1.0 < FSL < 1.25 within a non-liquefiable layer may be considered non-liquefiable. However, if a liquefiable layer includes both FSL ≤ 1.0 and 1.0 < FSL < 1.25 zones, the layer should be identified as likely liquefiable, but may be divided into separate layers for post-liquefaction strength estimation and slope stability analysis.

For an FSL > 1, several procedures are generally used for estimating partial pore pressure generation using Tokimatsu and Yoshimi (1983) for sand and Evans (1987) and Hynes (1988) for gravel (Marcuson et al., 1989). Considering ULE’s screening-level evaluation process, ULE analysts should use a 30 percent reduction in the drained strength for soils with 1.0 < FSL < 1.25 (ICB, 2013; Balakrishnan and Perlea, 2013). 20150427_GuidanceDoc.docx 6-13 Issue Date: April 2015
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6.8.2.3 Non-Liquefiable Cohesive Soils
Due to the transient seismic loading, non-liquefiable cohesive soils should be modeled using the undrained strengths. The generalized stress history and normalized soil engineering properties (SHANSEP) equation can be used to estimate the undrained shear strength from the estimated in situ effective stresses, σ′vo, and the maximum past pressure, σ′vm. su = S x(OCR)m x σ′vo
where
su is the undrained shear strength;
S is the normalized undrained shear strength ratio for normally consolidated soil; OCR is the overconsolidation ratio = σ′vm/ σ′vo;
σ′vo is the in situ vertical effective stress;
σ′vmis the maximum past pressure; and
m is an empirical constant that varies between 0.75 and 0.85 for most soils.

ULE analysts can use the special testing program results discussed in Section 5.0 to select appropriate values of the parameter S. In the absence of any site-specific data for finegrained soils, including ML and OH, a value of S of 0.25 is recommended (refer to Section 5.0 for soil group definitions). If vane shear strength data are available, these data should be evaluated during strength selection for seismic analyses.

Considering the relatively short durations of seismic shaking associated with 200-year return period seismic loading in the ULE study area, there will be no additional seismic modification factor applied to these static strengths to develop seismic strength parameters.

6.8.2.4 Non-Liquefiable Cohesionless Soils
Dense coarse-grained materials (i.e. non-liquefiable) are expected to dilate and potentially generate negative pore pressures during shear (when saturated). Due to the generation of negative pore pressures, the undrained shear strength of these materials could be higher than their drained strength, especially under rapid loading conditions. Because these materials are also permeable, it is prudent not to rely on negative pore pressures; rather, ULE analysts should use drained strengths to analyze these materials (see Section 5.0). The shear strength of these materials is generally represented by a friction angle and pre-seismic pore pressures. Typical dense coarse-grained material types include dense natural coarsegrained sediments and compacted fills composed of relatively clean gravels and sands.

Tension Cracks
Where tension cracks occur in the levee embankment, the soil strength along the failure surface above the depth of the cracks does not contribute to slope stability and negative normal stresses may develop at the interfaces between slices in the slope stability 20150427_GuidanceDoc.docx 6-14 Issue Date: April 2015
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calculations. The following crack depth guidance table is to be used in the ULE post-seismic slope stability assessment. These values were selected after discussion with the DWR seismic review panel. When the top 5 feet of the levee embankment is composed of granular fill, there is no need to consider a tension crack for slope stability analyses.

Material Crack Depth (feet)1
SP, SW, SM, SP-SM, SW-SM 0
ML, CL-ML, SC 3
CL 5
CH, MH 8
1 The maximum crack depth may not exceed ⅓ levee height (measured from the landside toe) In general, for the seismic slope stability analyses, tension cracks do not need to be modeled as filled with water. However, if conditions of water-filled tension cracks are present, ULE analysts should include these in analyses.

6.8.3 Post-Seismic Slope Stability Analyses
Using the seismic shear strengths discussed in Section 6.8.2, ULE analysts should complete post-seismic slope stability analyses using the search routines in the slope stability software.

No horizontal seismic coefficient is used in post-seismic analyses. See Figure 6-1 for key steps in the seismic vulnerability analysis process.

If the calculated FSPS for any critical shear surface is less than 1.0, then the segment is classified as having high vulnerability, and no further analysis is required. If the FSPS is greater than 1.3, the segment is classified as having low vulnerability, unless settlements due to volumetric strain (Section 6.9) result in a higher vulnerability class. If the FSPS is between 1.0 and 1.3, ULE analysts should perform seismic deformation analysis as described in Section 6.8.4. This FSPS range applies to the seismic environment and range of PHA values in ULE study areas and may not be appropriate for other geographic areas.

ULE analysts may copy and modify the slope stability files completed for the static analyses meeting all five static criteria (i.e., existing or remediated conditions, as appropriate) for seismic slope stability analyses. Modifications include changing the piezometric line and pore pressure information as discussed in Section 6.2, and changing the material shear strength as discussed in Section 6.8.2. If the WSE is above the landside toe, seepage analysis may need to be performed to calculate pore pressures for use in the slope stability analysis.

6.8.4 Seismic Deformation Analyses
Based upon the results of the post-seismic slope stability analyses for the seismic segments, if factors of safety are in the range of 1.0 to 1.3, then seismic deformation analyses will be implemented as described below.

The seismic deformation analysis presented in this document is based on the principles of Newmark-type deformation analysis (e.g., Makdisi and Seed, 1978; Seed, 1979; Idriss, 1985). The primary goal of the seismic deformation analysis is to estimate vertical deformations that are then used to assign a seismic vulnerability class (Table 6-1) for each 20150427_GuidanceDoc.docx 6-15 Issue Date: April 2015
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seismic segment. The results from seismic deformation analyses including vulnerability classes will be presented in each study area’s GER Volume 2 (Figure 1-16).

The Newmark-type deformation analysis is based on the rigid-block model with several simplifying assumptions including the assumption that displacements occur along a single, well-defined slip surface and accelerations and corresponding inertial forces act in the direction of initial movement at the center of gravity of the slide mass. Note that this type of deformation analysis may not yield highly accurate results for levees because of the simplifying assumptions. However, for a screening-level study, this approach is judged to be reasonable. A more sophisticated seismic deformation analysis is not warranted at this level of study and could be performed when the design of seismic improvements are undertaken.

As shown in Figure 6-1, the key steps in the Newark-type deformation analysis process are outlined below with a detailed discussion presented in the following text:
 Estimate the earthquake-induced accelerations acting on a slide mass. Typically, earthquake-induced accelerations on a slide mass are calculated using dynamic site response analysis. However, for ULE, a simplified approach is used to estimate the maximum average earthquake-induced acceleration on a slide mass (Kmax) as shown on Figure 6-4. The relationships of Figure 6-4 are based on two-dimensional, dynamic response analyses of representative levee and foundation conditions as described in the Levee Seismic Vulnerability Assessment Methodology Report (URS, 2008).  Perform pseudo-static slope stability analysis using a horizontal seismic coefficient, K, equal to one-half of Kmax. As discussed below, if the minimum FS is greater than 1.0, the section may be classified as having low vulnerability unless settlements due to volumetric strain (Section 6.9) result in a higher vulnerability class.  Identify and estimate potential sliding masses and associated seismic yield coefficients (referred to as yield acceleration, Ky). Ky represents the minimum horizontal acceleration required to produce a FS equal to 1.0. In the context of Newmark’s sliding-block analogy, Ky is interpreted as the minimum acceleration required to initiate downslope displacement of a slide mass. Ky is often calculated using the limit-equilibrium pseudostatic slope stability analysis.  Estimate the permanent deformation of a slide mass using Ky and Kmax as input parameters (Figure 6-5). This method assumes that permanent deformation initiates when the earthquake-induced accelerations acting on a slide mass exceed Ky on the slip surface. At this point, the slide mass begins to experience shear slippage relative to the underlying slope. Seismic loading is cyclic in nature, and the cyclic increase, decrease, and reversal of lateral loading generally produces periods of time during which relative slippage occurs. Multiple analyses have been performed using actual earthquake time histories, and with different ratios of Ky and Kmax, to develop average curves of resulting relative displacement as a function of Ky/Kmax and the duration of the number of loading cycles (URS, 2008). The curves shown in Figure 6-5 have been selected as suitable for screening-level predictions of resulting seismic deformations under ULE seismicity conditions. In other geological and seismic regions, different curves of this type would be needed.
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Estimate Kmax Values for the Potential Shear Surfaces
Kmax is defined as seismic loading for a potential sliding mass as represented by the horizontal equivalent acceleration, which accounts for the cumulative effect of the nonuniform horizontal acceleration distribution in the overlying deformable material (Seed and Martin, 1966). Based on this concept, Kmax represents the maximum seismic coefficient for the sliding mass: Kmax = max (horizontal equivalent acceleration)/g.

Using the Kmax vs. PHA charts shown on Figure 6-4, estimate the Kmax values for shallow and deep shear surfaces based on the geometrical symmetry of the levee.  Symmetric or Softer Levee: levee sections where the landside and waterside toe elevations are about the same, and/or the foundation is generally softer (e.g., Holocene).

For these conditions, a softer seismic response might be expected; and, for the purposes of this screening-level study, the soft Kmax curve is selected from Figure 6-4.  Asymmetric or Stiffer Levee: levee sections where the difference between the elevation of the landside and waterside toe is greater than one levee height, measured from the higher of the landside toe and waterside toe of the levee, and/or the foundation is generally stiffer (e.g., Pleistocene). Then, a stiffer seismic response might be expected; and, for the purposes of this screening-level study, the stiff Kmax curve is selected from Figure 6-4.
 Intermediate Levee Symmetry/Stiffness: a levee section that falls between the symmetric and asymmetric definitions from above might be expected to show a mediumstiff seismic response; and, for the purposes of ULE’s screening-level study, the medium Kmax curve is selected from Figure 6-4.

Perform Pseudo-Static Slope Stability Analyses with A Single Seismic Coefficient Considering the seismic environment of ULE study areas, including PHA levels and an earthquake magnitude of 6.5, negligible Newmark displacements will result when the Ky/Kmax ratio is 0.5 or greater (see Figure 6-5). As a screening tool to limit the need for full Newmark displacement analysis, a pseudo-static slope stability analysis can be performed using a horizontal seismic coefficient, K, equal to one half of Kmax (K = 0.5Kmax). If the resulting calculated minimum FS for this acceleration level is equal to 1.0, then the K value is by definition the yield acceleration (Ky) and the Ky/Kmax ratio is equal to 0.5. The resulting Newmark displacement is approximately 0.16 feet as shown on Figure 6-5. If the minimum FS is greater than 1.0, the Ky/Kmax ratio will be greater than 0.5 and the corresponding Newmark displacement will be less than 0.16 feet. Consequently, if the minimum calculated FS for an acceleration of K = 0.5Kmax is equal to or greater than 1.0, then the analysis section may be considered low vulnerability (i.e. deformation will be less than 0.16 feet) unless settlement due to volumetric strain (Section 6.9) results in a higher vulnerability class.

ULE analysts should note that K should be applied only in the horizontal direction. In addition, circular and wedge-shaped failure surfaces should be checked on the waterside and landside at deep and shallow depths. Note that the Kmax value is different for deep versus shallow failure surfaces. As general guidance, shallow failure surfaces are those considered to penetrate a maximum of 2 to 3 feet below the levee toe (landside or waterside, depending on the analyzed slope). However, ULE analysts should exercise engineering judgment when selecting limiting depths for shallow surfaces. 20150427_GuidanceDoc.docx 6-17 Issue Date: April 2015
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Estimate the Yield Acceleration (Ky) Values
ULE analysts should only perform this step for study area sections that have a post-seismic FS between 1.0 and 1.3, and a pseudo-static FS with K=0.5Kmax that is less than or equal to 1.0.

ULE analysts should use the seismic shear strengths discussed earlier in Section 6.8.2.

Pseudo-static analyses should be completed using the search routines in the slope stability software to calculate the yield acceleration, Ky. Ky is defined as the minimum horizontal acceleration resulting in a just-stable condition equivalent to an FS of 1.0.

For each analysis section, pseudo-static slope stability analyses need to be completed for a range of horizontal seismic coefficients (e.g., K = 0.05g, 0.10g, 0.15g, etc., up to K = 0.5Kmax, as needed) to estimate the yield acceleration value. Circular and wedge-shaped failure surfaces should be checked on the waterside and landside at deep and shallow depths.

The Ky value for each potential failure mode (i.e., waterside and landside, deep and shallow, circular and wedge), should be selected as the K value that corresponds to an FS of 1.0.

Determine Vertical Newmark-Type Deformation
Based on the Kmax and Ky values determined above, vertical deformation is estimated as outlined below.

1. Estimate the minimum Ky/Kmax ratio value.

Calculate the Ky/Kmax ratios for each potential failure mode (i.e., waterside and landside, deep and shallow, circular and wedge) and select the minimum value of the Ky/Kmax ratio.

Note that the minimum Ky/Kmax ratio value is not necessarily given by the minimum Ky.

2. Estimate the Newmark-type displacements.

Using the minimum Ky/Kmax ratio estimated for each study section, calculate the Newmark-type displacements from the chart shown on Figure 6-5. Displacements are estimated for a moment magnitude, Mw = 6.5 event.

For ULE’s screening-level study, a 0.7 foot of vertical displacement for every 1.0 foot of Newmark displacement (along the failure plane) is recommended for estimating freeboard loss (vertical displacements).

6.9 Volumetric Settlement
Settlement associated with the mechanisms such as ground loss due to sand boil ejection and dissipation of excess pore pressure (i.e., post-liquefaction reconsolidation settlement) is known as volumetric strain. Volumetric settlements are added to the vertical settlement, as estimated from seismic deformation analysis, when thick, loose deposits are evaluated.

Deposits thicker than 20 feet of potentially liquefiable soil with (N1)60-cs less than 15 are considered for volumetric strain settlement. The volumetric strain should be calculated using the CSR value for the liquefiable layer, the (N1)60-cs value of the liquefiable layer, and the relationship recommended by Wu and Seed (2004) as presented in Seed et al. (2003). Cetin 20150427_GuidanceDoc.docx 6-18 Issue Date: April 2015
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et al. (2009) compares four commonly-used methods to evaluate volumetric settlement and actual field performance case histories. A summary of the four methods is shown in Table 65
Table 6-5 Mean Accuracy and Dispersion of Volumetric Settlement Methods Method Mean Accuracy1 Dispersion
Tokimatsu and Seed (1984) 1.45 R2=0.33
Ishihara and Yoshimine (1992) 0.90 R2=0.42
Shamato et al. (1998) 1.93 R2=0.36
Wu and Seed (2004) 0.98 R2=0.33
1 Ratio of average actual to average predicted settlement Based on the comparison, the overall dispersion (or variances/uncertainties) are not significantly different; R2 values of between 0.33 and 0.42 are all relatively poor. The mean accuracy indicates the value by which all predicted settlements must be multiplied to provide an overall net-zero balance against the field settlements observed. Tokimatsu and Seed (1984) and Shamato et. al. (1998) tend to underestimate actual observed settlements, and require scaling factors of 1.45 and 1.93, respectively, in order to zero out this bias. Ishihara and Yoshimine (1992) tend to slightly overestimate observed settlements, requiring a scaling factor of 0.90. Wu and Seed (2004) have negligible net bias represented by a net scaling factor of 0.98. Considering this negligible bias, Wu and Seed (2004) has been adopted for ULE seismic vulnerability evaluations.

Figure 610 shows the plot for estimating volumetric settlement.

6.10 Vulnerability Assessment
To establish the seismic vulnerability classification for a given segment, first freeboard loss is calculated by adding the Newmark-type vertical deformation and volumetric settlement as applicable8
. Freeboard loss is then evaluated as a percentage of levee height. The levee height is estimated from the hinge point on the landside toe. Finally, based upon the amount of deformation, a judgment is made concerning the potential for significant damage to internal structures in the levee (e.g., cutoff walls).

ULE analysts should assess the seismic vulnerability class of the evaluated levee segments using the seismic vulnerability classification system presented in Section 6.4 and Table 6-1.

ULE analysts should document the vulnerability class of the seismic segments on a levee alignment map in each study area’s GER Volume 2.
8 If the Newmark-type vertical deformation is already generating a high seismic vulnerability classification, there is no need to calculate volumetric settlement.
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6.11 Seismic Vulnerability Assessment of Frequently-Loaded Levees (Urban-Non-Project Study Areas)

6.11.1 Criteria
ULE analysts should perform seismic vulnerability assessments for frequently-loaded levees in accordance with ULDC guidelines as they appear in Section 7.7.2 and Table 7-3. Based on the potential consequences, a higher ground motion level may be required for assessment and, in the absence of landside or waterside toe explorations, liquefaction analysis for crown explorations may need to be performed using landside or waterside CSR values, which are typically higher than the crown CSR values as demonstrated by Athanasopoulos-Zekkos and Seed (2013).

As noted in ULDC and shown in Table 6-6 below, for frequently-loaded levees with less than 5 feet of freeboard, the earthquake-induced deformations should be limited to less than 3 feet of overall (vertical and horizontal) deformation and about 1 foot of vertical displacement.

Seismic vulnerability analyses of frequently-loaded levees need to be performed as part of existing conditions analyses for each study area’s GER Volume 1. The levee alignment maps showing different vulnerability classes will be presented in the GER Volume 1 for frequently-loaded levees. A flow chart of the general protocol for assessment of frequentlyloaded levees is presented in Figure 6-11.

The seismic vulnerability assessment for frequently-loaded levees requires a robust analysis approach considering the consequences of levee failure. ULE analysts should apply the analysis approach presented in this Guidance Document using sound engineering judgment for such levees. If the estimated deformation of a given levee segment is close to the acceptable values, a more sophisticated seismic deformation analysis may be required to judge the need for seismic remedial alternatives.

Table 6-6 Criteria for Seismic Vulnerability of Frequently-Loaded Levees Amount of Total
Displacement
Amount of Vertical2
Displacement
Potential for Significant
Damage to Internal
Structures
Seismic Vulnerability
< 3 feet < 1 foot No Meets Criteria
≥ 3 feet ≥ 1 foot Yes Does Not Meet Criteria
1 This table presents criteria for frequently-loaded levees with less than 5 feet of freeboard. For larger cross sections and freeboard, larger deformation may be allowed based on engineering analysis and judgment (see ULDC Section 7.7.2 [DWR, 2012]). 2 Vertical displacement can be estimated as 0.7 times the total deformation from simplified deformation analysis (such as Newmark type displacement), and by adding volumetric settlement as applicable.

6.11.2 Seismic Remediation
If frequently-loaded levee segments do not meet seismic vulnerability criteria, the remediation protocols identified in the Conceptual Seismic Levee Remediation Alternatives and Cost Estimating Templates (URS, 2014) should be followed and verified by assessing 1 20150427_GuidanceDoc.docx 6-20 Issue Date: April 2015 SECTION 6.0 SEISMIC ANALYSIS
the post-seismic displacement criteria identified in Table 6-6. Upon verification, conceptual cost estimates following the guidance of Section 8 should be prepared.

6.12 References for Seismic Analysis
Athanasopoulos-Zekkos, A., Seed, R. 2013. “Simplified methodology for consideration of two-dimensional dynamic response of levees in liquefaction-triggering evaluation.” Journal of Geotechnical and Geoenvironmental Engineering, 139 (11).

Balakrishnan, A., Perlea, V. 2013. “Seismic Review Panel Report,” Seismic Review Panel Meeting on December 13, 2013. Prepared for DWR.

Beikae, M., Idriss, I., Hudson, M. 2003. User’s Manual for QUAD4M, A Computer Program to Evaluate the Seismic Response of Soil Structures Using Finite Element Procedures and Incorporating a Compliant Base. Center for Geotechnical Modeling, University of California, Davis, CA.

Boulanger, R., Idriss, I. 2004. Evaluating the potential for liquefaction or cyclic failure of silts and clays. Report UCD/CGM-04/01. Center for Geotechnical Modeling, University of California, Davis, CA.

Boulanger, R., Idriss, I. 2007. “Evaluation of Cyclic Softening in Silts and Clays,” Journal of Geotechnical and Geoenvironmental Engineering, American Society of Civil Engineers.

Bray, J., Sancio, R. 2006. “Assessment of the Liquefaction Susceptibility of Fine-Grained Soils,” Journal of Geotechnical and Geoenvironmental Engineering, American Society of Civil Engineers.

Cetin, K., Seed, R., Der Kiureghian, A., et al. 2004. “Standard penetration test-based probabilistic and deterministic assessment of seismic soil liquefaction potential.” Journal of Geotechnical and Geoenvironmental Engineering, 130 (12).

Cetin, K., Tolga Bilge, H., Wu, J., et al. 2009. “Probabilistic Model for the Assessment of Cyclically Induced Reconsolidation (Volumetric) Settlements.” Journal of Geotechnical and Geoenvironmental Engineering. Volume 135.

Department of Water Resources. 2012. Urban Levee Design Criteria. May.

Evans, M. 1987. “Undrained Cyclic Triaxial Testing of Gravels – The Effects of Membrane Compliance,” Ph.D. dissertation, University of California, Berkeley. California.

GEO-SLOPE International Ltd. 2007. Stability Modeling with SLOPE/W 2007: An Engineering Methodology. Fourth Edition.

Hynes, M. 1988. “Pore Pressure Generation Characteristics of Gravels under Undrained Cyclic Loading,” Thesis. University of California, Berkeley.

Idriss, I. 1985. “Evaluating seismic risk in engineering practice,” Proceedings of the 11th International Conference on Soil Mechanics and Foundation Engineering, San Francisco, California and Balkema, Rotterdam.
20150427_GuidanceDoc.docx 6-21 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS
Independent Consultant Board. 2013. “Independent Consultant Board Report,” Seismic Meeting of December 13, 2013. Prepared for DWR.

Ishihara, K., Yoshimine, M. 1992. “Evaluation of settlements in sand deposits following liquefaction during earthquakes.” Soils and Foundations, 32(1).

Kulhawy, F., Mayne, P. 1990. Manual On Estimating Soil Properties for Foundation Design.

Report EL-6800. Electric Power Research Institute.

Makdisi, F., Seed, H. 1978. “Simplified procedure for estimating dam and embankment earthquake-induced deformations.” Journal of Geotechnical Engineering Division, ASCE, 104 (GT7).

Marcuson, W., Hynes, H., Franklin, A. 1990. “Evaluation and use of Residual Strength in Seismic Safety Analysis of Embankments”. Earthquake Spectra, Volume 6 (3).

Moss, R. Seed, R. Kayen, R. et al. 2006. “CPT-Based Probabilistic and Deterministic Assessment of In Situ Seismic Soil Liquefaction Potential.” Journal of Geotechnical and Geoenvironmental Engineering, Volume 132, Number 8. August. Errata to Equation (5) are published in the Journal of Geotechnical and Geoenvironmental Engineering, ASCE.

Robertson, P., Campanella, R. 1983. “Interpretation of cone penetration tests.” Canadian Geotechnical Journal. 20 (4), 718-745.

Seed R., Harder, L. 1990. “SPT-Based Analysis of Cyclic Pore Pressure Generation and Undrained Residual Strength.” Proceedings of H.B. Seed Memorial Symposium, Volume 2. BiTech Publishing, Vancouver.

Seed, H. 1979. “Considerations in the earthquake-resistant design of earth and rockfill dams.” Geotechnique. 29 (3).

Seed, H., Martin, G. 1966. “The Seismic Coefficient in Earth Dam Design,” ASCE Journal of Soil Mechanics. Volume 92.

Seed, R, Cetin, K., Moss, R., et al. 2003. “Recent Advances in Soil Liquefaction Engineering:

A Unified and Consistent Framework,” Keynote Address, Proceedings, 26th Annual Geotechnical Spring Seminar. Los Angeles Section of the GeoInstitute, American Society of Civil Engineers.

Shamoto, Y., Zhang, J., Tokimatsu, K. 1998. “Methods for evaluating residual post liquefaction ground settlement and horizontal displacement.” Soils and Foundations. 2 (2).

Southern California Earthquake Center. 1999. Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and Mitigating Liquefaction in California. March.

Tokimatsu, K., Seed, H. 1984. “Simplified Procedures of the Evaluation of Settlements in Clean Sands.” Report Number UCB/GT-84/16, University of California, Berkeley. 20150427_GuidanceDoc.docx 6-22 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS
Tokimatsu, K., Yoshimi, Y., 1983, “Empirical Correlation of Soil Liquefaction Based on SPT NValue and Fines Content,” Japanese Society of Soil Mechanics and Foundation Engineering, Soils and Foundations, Volume 15 (4).

USACE. 2003. Engineering and Design – Slope Stability. EM 1110-2-1902.

URS Corporation. 2007. Probabilistic Seismic Hazard Assessment performed for the Delta Risk Management Study Phase 1 Project. Prepared for DWR.

URS Corporation. 2008. Levee Seismic Vulnerability Assessment Methodology Technical Memorandum. Prepared for DWR.

URS Corporation. 2012. Development of a 200-year Return Period Seismic Hazard Map for the Urban Levee Evaluations Program Region. Prepared for DWR.

URS Corporation. 2014. Conceptual Seismic Levee Remediation Alternatives and Cost Estimating Templates. Prepared for DWR.

Wright, S. 1999. “A Computer Project for Slope Stability Calculations.” Technical Manuals for UTEXAS4, May 1999, Revised September 1999, Shinoak Software, Austin, Texas.

Wu, J., Seed, R. 2004. “Estimating of liquefaction-induced ground settlement (case studies)”.

Proceedings of the 5th International Conference on Case Histories in Geotechnical Engineering. Paper 3.09. New York.
20150427_GuidanceDoc.docx 6-23 Issue Date: April 2015
SECTION 6.0 SEISMIC ANALYSIS
20150427_GuidanceDoc.docx 6-24 Issue Date: April 2015

FIGURES

FIGURES
Section 6
Figure 6-1 Seismic Vulnerability Analysis – Key Steps (Intermittently Loaded Levees)
Figure 6-2 Seismic Hazard Map
Figure 6-3 Recommended τmax versus Depth
Figure 6-4 Recommended Kmax vs. Input Motion PHA
Figure 6-5 Recommended Newmark Displacement vs. Ky/Kmax Figure 6-6 GER Liquefaction Assessment Flow Chart
Figure 6-7 Summary Guidance for Evaluating Fine-Grained Soils Liquefaction Susceptibility
Figure 6-8 Cyclic Resistance Ratio, equation by Cetin et. al., 2004.

Figure 6-9 Seed-Harder Plot for Residual Strength
Figure 6-10 Volumetric Strain
Figure 6-11 Seismic Vulnerability Analysis – Key Steps (Frequently Loaded Levees)

Figure
6-1
Seismic Vulnerability Analysis – Key Steps

Classify as “High Vulnerability”
Yes
No
Classify as “Low Vulnerability” unless
Volumetric Strain (Step 3f ) results in a
higher vulnerability class
Is
FSPS > 1.3?
Is
FS ≥1?
Step 4: If Warranted, Perform More Advanced Seismic Deformation Analysis (See Section 6.11) Step 3: Perform Simplified Seismic Deformation Analysis Evaluate and document longitudinal extent of liquefiable soils Select seismic levee segments and engineering cross-sections for seismic stability and deformation analyses
Step 1: Select Seismic Segments and Cross Sections for Seismic Vulnerability Analyses SEISMIC VULNERABILITY – KEY STEPS (INTERMITTENTLY-LOADED LEVEES) G:\DWR-7418\Project Files\TASK AREAS\General\GeotechAnalysis\GuidanceDocument\Final\Figures\Fig 6-1 Seismic Vulnerability.indd "
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M o u n t
D i a b l o
M o u n t
D i a b l o
G r e e n v i l l e
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All of the area north of the 0.11 g
contour should be considered
at the same PHA level of 0.11 g

0.11 0.11

0.13 0.2

0.15 0.3

0.25 0.35

0.4 0.4

0.3 5
Yolo
Yuba
Solano
Butte
Sutter
San Joaquin
Colusa
Sacramento
Placer
Contra Costa
Alameda
Glenn
Nevada
Napa
Stanislaus
El Dorado
Solano
Contra Costa
Sierra
Solano
Lodi
Antioch
Concord Stockton
Livermore
Fairfield
Vacaville
Pleasanton
Marysville
San Leandro
Walnut Creek
Citrus Heights
Sacramento
121.5° W
121.5° W
122° W
122° W

39.5° N 39.5° N
39° N 39° N

38.5° N 38.5° N
38° N 38° N
0 5 10 15 20 2.5
Miles
0 9 18 27 36 4.5
Kilometers
¯
PHA HAZARD FOR A 200-YEAR RETURN PERIOD
AND STIFF SOIL BASE CONDITION (VS30 335 M/SEC) FOR

MARYSVILLE, SACRAMENTO, AND

STOCKTON REGIONS
L:\Projects\DWR\GEOTECHNICAL\Urban\GuidanceDoc\ArcMap\GDOCD1F1PGAHAZ200_1.mxd TNC 08.06.2014 SAC Service Layer Credits: Sources: Esri, GEBCO, NOAA,
National Geographic, DeLorme, NAVTEQ, Geonames.org,
and other contributors

URBAN LEVEE EVALUATIONS
Department of Water Resources
Division of Flood Management
Figure
6-2
Seismic Hazard Map
PHA (g) Contour Line
ULE Study Area
Mapped fault used in
the hazard analysis
Concealed fault or
source zone used in
the hazard analysis
NOTES:

AMPLIFICATION OF THE PHAs

MAY BE REQUIRED BASED
ON SITE-SPECIFIC VS,30.

Recommended τmax versus Depth Figure
6-3
Department of Water Resources
Division of Flood Management URBAN LEVEE EVALUATIONS
PHI)
(1) Select PHI from Figure 6-1
Recommended Kmax vs Input Motion PHA Figure
6-4
Department of Water Resources
Division of Flood Management

URBAN LEVEE EVALUATIONS
Levee
Shape
Resulting
Response
Symmetric “Softer”
Less
Symmetric “Medium”
Asymmetric “Stiffer”

0.5 Recommended Newmark Displacement
vs Ky/Kmax Figure
6-5
Department of Water Resources
Division of Flood Management

URBAN LEVEE EVALUATIONS
100
.
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.
.
.
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10 .
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0.1 .
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0.01 0 0.2 0.4 0.6 0.8 1
Ky/Kmax
Newmark Displacement (ft)
MW = 6
MW = 6.5
MW = 7
GER Liquefaction Assessment Flow Chart Figure
6-6
Department of Water Resources
Division of Flood Management

URBAN LEVEE EVALUATIONS
Select appropriate number and location of
representative explorations to perform
liquefaction spreadsheet analyses.

SELECT

REPRESENTATIVE EXPLORATIONS

DEFINE EXTENTS OF

LIQUEFIABLE LAYERS
Define extents of likely and less likely liquefiable layers identified during the liquefaction spreadsheet analysis by extrapolation based on the geologic profile and
stratigraphy (Section 6.7.3).

PERFORM

LIQUEFACTION ASSESSMENT
Perform liquefaction spreadsheet analyses
on selected explorations to identify likely and less
likely liquefiable layers. (Section 6.7.2)
Document liquefaction results in the following:
 Liquefaction analysis spreadsheets
 Longitudinal geologic profile
Use ULE Program guidelines to establish
the zone of soils to be assessed. (Section 6.7.1)

ESTABLISH LIQUEFACTION

ASSESSMENT ZONE
Use ULE Program guidelines to identify soils
in assessment zone that are not susceptible
to liquefaction. (Section 6.7.1)

SCREEN OUT SOILS THAT

ARE NOT LIQUEFIABLE

DOCUMENT RESULTS
Summary Guidance for Evaluating
Fine-Grained Soils Liquefaction Susceptibility Figure
6-7 URBAN LEVEE EVALUATIONS
Clay-like: Non-susceptible to liquefaction
Sand-like: Susceptible to liquefaction
605040302010
74 0 10 20 30 40 50 60 70 80 90 100
PI < 10 CL-ML
LL (Liquid Limit)
PI (Plasticity Index) CL CH
U-Line
MH
ML
Note: See Section 6.7.1 for further clarification of liquefaction susceptibility.

Department of Water Resources Division of Flood Management Cyclic Resistance Ratio, equation by Cetin et al., 2004 Figure 6-8
Department of Water Resources Division of Flood Management

URBAN LEVEE EVALUATIONS
Seed-Harder Plot for Residual Strength Figure
6-9 URBAN LEVEE EVALUATIONS
50 For the ULE Program

1. Use the lower 1/3 line for
Sur selection

2. At or below (N1)60-cs = 4,
use Sur = 50 psf
50 Equivalent Clean Sand Blowcount, (N1)60-cs-Sur
Department of Water Resources
Division of Flood Management
Volumetric Strain Figure
6-10 URBAN LEVEE EVALUATIONS
SOURCE:

RECENT ADVANCES IN SOIL LIQUEFACTION ENGINEERING: A UNIFIED AND CONSISTENT FRAMEWORK By R.B. Seed, L.O. Cetin, R.E.S. Moss, A.M. Kammerer, J.Wu, J.M. Pestana, M.F. Fiemer, R.B. Sancio, J.D. Bray, R.E. Kayen, and A. Faris (26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Keynote Presentation H.M.S. Queen Mary, Long Beach, CA April 30, 2003)
Department of Water Resources
Division of Flood Management
Does total
seismic
deformation meet
criteria?
Figure
6-11
Seismic Vulnerability Analysis – Key Steps

URBAN LEVEE EVALUATIONS
Department of Water Resources
Division of Flood Management
Step 2: Perform Post-Seismic Stability Analysis
Step 3a: Compute Kmax using Figure 6-4
Step 3e: Estimate vertical deformation as 0.7 times total Newmark displacement
Step 3c: Compute Ky value for sliding mass
Step 3d: Compute Newmark displacement using Kmax, Ky, and Figure 6-5 Yes
Step 3b: Perform pseudo-static stability analysis using K=0.5 Kmax No
Classify as Meets Criteria unless
volumetric strain (Step 3f ) results in a
higher vulnerability class
Is
FSPS < 1?
Yes
No
Perform post-seismic stability analysis
Continue to Step 3
No further analysis is needed.

Classify as Does Not Meet Criteria
Yes
No
Classify as Meets Criteria unless
Volumetric Strain (Step 3f ) results in a
higher vulnerability class
Is
FSPS > 1.3?
Is
FS ≥1?
Step 4: If Warranted, Perform More Advanced Seismic Deformation Analysis (See Section 6.11) Step 3: Perform Simplified Seismic Deformation Analysis Evaluate and document longitudinal extent of liquefiable soils Select seismic levee segments and engineering cross-sections for seismic stability and deformation analyses
Step 1: Select Seismic Segments and Cross Sections for Seismic Vulnerability Analyses SEISMIC VULNERABILITY – KEY STEPS (FREQUENTLY-LOADED LEVEES) Proceed to Seismic
Remediation Analysis
Document Results Yes
No
Step 3f: Calculate volumetric strain, if necessary
G:\DWR-7418\Project Files\TASK AREAS\General\GeotechAnalysis\GuidanceDocument\Final\Figures\Fig 6-11 Seismic Vulnerability.indd

APPENDIX J

APPENDIX J
Liquefaction Triggering Spreadsheets

REFERENCES:

1. 2.

3. 4.

5. 6.

NOTES & INSTRUCTIONS:

3. Color Code for Analysis Data Entry Color Code for Tabs

14. Factor of safety against liquefaction (FSL) is capped at 5.0

15. CPT data should not be entered for depths of 0.5 feet and shallower.

CONTRIBUTORS:

DWR URBAN LEVEE GEOTECHNICAL EVALUATIONS PROGRAM (ULE)

CPT BASED LIQUEFACTION ANALYSIS FOR ULE
Moss, R.E.S., Seed, R.B., Kayen, R.E., Stewart, J.P., Der Kiureghian, A. and Cetin, K.O., 2006. "CPT-Based Probabilistic and Deterministic Assessment of In Situ Seismic Soil Liquefaction Potential". Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No. 8, August 2006, pp. 1032-1051, (doi 10.1061/(ASCE)1090-0241(2006)132:8(1032)). Errata to Equation (5) are published in the Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Sep 2007. Page 1177.

Lunne, T., Robertson, P. K. and Powell, J.J.M., 1997. Cone Penetration Testing in Geotechnical Practice. Blackie Academic & Professional. London.

13. In the normal distribution function for CRR, a Probability (PL) value of 15% was used in accordance with Reference 4

11. τmax options are "Crest", "Waterside", or "Landside" to obtain τmax values from the tabs Crest_Tau, Landside_Tau, and Waterside_Tau. The τmax values are given at 0.5 ft. intervals. The maximum depth for crest τmax = 140 feet, Landside τmax = 120 feet, and Waterside τmax = 100 feet.

URS Corporation 2013. Guidance Document for Geotechnical Analysis, Urban Levee Geotechnical Evaluations Project, Version 14.

Michael Luebbers, GE

16. Liquefaction susceptibilty of fine-grained soils can be assessed based on laboratory data and the criteria in Reference 3 (PI <10, LL<35, and w > 0.8 LL are susceptible to liquefaction). For intermittently loaded levees, CL materials are not considered susceptible to liquefaction. For frequently loaded levees, the Atterberg Limits criteria above apply to CL materials. Analysts may manually enter whether fine-grained soil is susceptible to liquefaction in Column AZ ("Liquefaction Susceptibility Based on Soil Type") based on laboratory data or evaluation of chacteristics based on soil deposits, in the absence of laboratory data. Atterberg Limits data sould not be entered for coarse-grained soils.

MS Office Excel 2003 SP2 Part of MS Office Standard Edition 2003 Date (Version 2.1) January 15, 2014

8. Note on Thin Layer Correction: A maximum number of 30 layers can be entered for thin layer correction. Thin layer correction (Cthin) can be made only for standard cone (diameter = 1.4055"). Interpolated Cthin is provided for maximum thin layer thickness (h) of 2.4 feet (for (qcB)avg/(qcA)avg between 2 and 5) and

7.2 feet (for (qcB)avg/(qcA)avg between 5 and 10).

Bray, J.D., Sancio, R.B., 2006. "Assessment of the Liquefaction Susceptibility of Fine-Grained Soils". Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No. 9, September 2006, pp. 1165-1177.

1. The user should understand the methodology and assumptions presented in the references before using this spreadsheet. The CPT-based liquefaction assessment proposed by Reference 1 is adopted in the calculations. Example presented in the spreadsheet was used to verify the equations in the spreadsheet, and it is not part of any liquefaction analysis for any task order. Use of this example to justify any analysis is not permitted.

Seed, R.B., Cetin, K. O. Moss, R. E. S., Kammerer, A. M., Wu, J., Pestana, J. M., Riemer, M. F., Sancio, R.B., Bray, J. D., Kayen, R. E., Faris, A., 2003. "Recent Advances in Soil Liquefaction Engineering : A Unified and Consistent Framework". 26th Annual ASCE Los Angeles Geotechnical Spring

10. CRR Values were calculated using Reference 1 and CSR values are calculated based on τmax values from Reference 3.

Robertson, P.K., and Wride (Fear), C.E., 1998. "Evaluating Cyclic Liquefaction Potential Using the Cone Penetration Test". Canadian Geotechnical Journal, 35, pp. 442–459.

9. CPT based soil behavior type and zone numbers (both SBT and SBTn zone numbers and soil types based on Reference 2) are included in the "Calculation Sheet" to facilitate in assessing soil liquefaction susceptibility based on soil type. Users should evaluate any apparent change in soil behavior type within thin layers in assessing liquefaction susceptibility based on soil type.

Ahmed Bayoumi, PhD and Khaled Chowdhury, GE
Reference Sheets

7. Normalized tip resistance values were calculated using iterative process in accordance with Reference 1. Values were calculated using iterative process in two ways: a. 5 iterations using EXCEL equations and b. 10 iterations using internal codes. Two values are presented to evaluate accuracy of the internal codes. The internal codes derived normalized tip resistance values are used subsequently in the spreadsheet.

Step 4: The User Manually Enters Selected Cthin in Column J of "Input Data and Thin Layer Sheet". Calculation Sheet" imports Cthin values from column J of "Input Data and Thin Layer Sheet".

4. The spreadsheet estimates the Factors of Safety against liquefaction in accordance with the procedure described in Reference 1. In accordance with Reference 3, FSL≤1 is considered "Likely Liquefiable" and 1<FSL<1.25 is considered "Less Likely Liquefiable". User shall be responsible for interpretation of the FSL results.

5. Input Data: selected raw and interpreted CPT data including tip resistance, sleeve friction, soil unit weight, SBT, and SBTn from "Raw Data Sheet" must be entered on sheet "Input Data and Thin Layer Sheet". In Reference 1, tip resistance qc refers to raw tip resistance.

Step 1: User enters depths to top and bottom of thin layer, average tip resistance in thin layer, (qcB)avg., and average tip resistance outside thin layer, (qcA)avg.

Step 2: The spreadsheet calculates Cthin using Figure 5 of Reference 1

6. Thin Layer Correction Procedure
The CPT tip resistance measurement at a particular point in a highly stratified soil column represents the resistance at the tip with respect to the layers above and below the tip. Depending on the thickness of the layer at the cone tip, the measured tip resistance value can be significantly different from the true tip resistance value of the stratum if it were a continuous thick layer. The sleeve resistance on the other hand, is thought to be not significantly affected by the layers above and below the sleeve; consequently, the friction ratio and Soil Behavior Type (SBT) will also be affected by a thin layer.

The evaluation of thin layers can be time consuming and requires significant judgment on the part of the user and requires extra review by a senior engineer.

Therefore, the liquefaction triggering analysis should be performed first without any consideration being given to thin layers. Only in areas where a potential for liquefaction is identified should the user check whether a thin layer may be present. If a thin layer may be present, the user should seek the input of a senior engineer.

Step 5: Due to modifying qc and friction ratio in the thin layer, re-classifying SBT is necessary (Reference 6). Zone number for soil behavior type (SBT and SBTn) must be entered manually by the user. The modified tip resistance and the corresponding friction ratio needed for SBT classification are provided in columns AK and AL in "Calculation Sheet" tab. Similarly Columns AP and AR are used to re-classify SBTn. SBT and SBTn classification charts are available in "Ref.

Sheet(2)_SBT" Tab.

Calculated Values

2. The results should be verified independently if the spreadsheet is used in a computer system different than the one indicated in the "verified with" cell. A hand calculation package should be prepared by the user.

Data Input By Analyst Calculation Sheet
Input Data and Thin Layer Sheet
Raw CPT Data Sheet

12. Guidance on selecting τmax curves: For CPTs located water-ward of a point one-third up the waterside slope of the levee, use the waterside curves. For CPTs located land-ward of a point one-third up the landside slope of the levee, use the landside curves.

Updated by (Version 2.1) Erik Julian, PE
Step 3: The average tip resistance representing the thin layer (qcB)avg and outside thin layer (qcA)avg must be selected by the user. For combinations of thin layer thickness (h) and tip resistance ratios (qcB)avg/(qcA)avg falling out of interpolation range, the user can refer to Figure 5 (Reference 1.) to select Cthin.

Ahmed Bayoumi, PhD and Anthony Deus
Gyeong-Taek Hong, PhD
Verified with (Version 2.0)
Date (Version 2.0) October 3, 2008
Results of Analysis
Verified with (Version 2.1) MS Office Excel 2010
Developed by (Version 2.0)
CSR Interpolation by (Version 2.0)
Detail Check by (Version 2.0)
Verified By (Version 2.0)
Verified By (Version 2.1) Khaled Chowdhury, GE
Detail Check by (Version 2.1) Kanax Kanagalingam, PhD, PE C:\Users\KC_Fuerstenberger\Desktop\Copy of CPT Liquefaction V2 1 (''Less Likely'')Calculation Sheet 8/6/2014 2 of 8 REFERENCES:

Analysis by: Date:

Checked by: Date:

Note: Crest/Landside/Waterside, and distance from Crest/Landside toe/Waterside toe

66.8 31.8 Note:

40.0 Note:
200

0.16 Crest

6.5 35.0

26.8 4
Depth Tip Resistance, qcSleeve Friction, fsFriction Ratio, RfTotal Unit WeightTotal, σvEffective During Exploration , σv'Effective During Earthquake, σv'Thin Layer Number, nSelected Thin Layer correction Factor, CThinUsed Thin Layer correction Factor, CThinTip Resistance Corrected for Thin Layer qc,thinFriction Ratio Corrected for Thin Layer, Rf,thinTip Normalized Exponent (initial), cTip Normalized Factor (initial), CqNormalized Tip Resistance (initial), qc1Tip Normalized Exponent (final), cTip Normalized Factor (final), CqNormalized Tip Resistance (final), qc1Tip Normalized Exponent, c Normalized Tip Resistance, qc1 Percent Difference between Values Obtained by Iterations and Internal Code Fines Adjustment for Tip Resistance, ∆qcModified Normalized Tip Resistance, qc1,modSoil Behavior Zone from Raw CPT Data SheetUpdated Tip Resistance in Thin Layer, qc,thin (Column AK)Updated Friction Ratio in Thin Layer, Rf,thin (Column AL)User-Selected Soil Behavior Zone - Only for Thin Layer (Based on Columns AK & AL)Soil Behavior Type, SBT Normalized Soil Behavior ZoneUpdated Normalized Tip Resistance in Thin Layer, qc1,thin (Column AP)Updated Normalized Sleeve Friction in Thin Layer, fs1,thinUpdated Friction Ratio for Normalized Tip Resistance in Thin Layer, Rf1,thin (Column AR)User-Selected Soil Behavior Zone - Only for Thin Layer (Based on Columns AP & AR)Normalized Soil Behavior Type, SBTn USCS ClassificationLiquid Limit, LLPlasticity Index, PIWater Content, wcFines Content, FCLiquefaction Susceptibility Based on Soil Type (Column AZ)Below Design Groundwater Level (Column BA) τmax
Cyclic Stress Ratio, CSRCyclic Resistance Ratio, CRRFactor of Safety, FSLFSL < 1.25 (Column BF)qc1,mod < 100 tsf (Column BG)Final Assessment Based on Columns AZ, BA, BF, and BGFactor of Safety, FSLComment(Likely Liquefiable for FSL ≤ 1;Less Likely Liquefiable for1.0 < FSL < 1.25;Non-Liquefiable for FSL ≥ 1.25) (ft) (tsf) (tsf) (%) (pcf) (psf) (psf) (psf) (-) (-) (-) (tsf) (%) (-) (-) (tsf) (-) (-) (tsf) (-) (tsf) (%) (tsf) (tsf) (-) (tsf) (%) (-) (-) (-) (tsf) (tsf) (%) (-) (-) (-) (-) (-) (%) (%) (Yes/No) (Yes/No) (psf) (-) (-) (-) (Yes/No) (Yes/No) (Yes/No) (-) (-)

0.7 45.3 0.89 2.0 118 77 77 77 - - - - - 0.48 1.70 76.9 0.42 1.70 76.9 0.42 76.9 0.00 9.3 86.2 7 - - silty sand to sandy silt 8 - - - Very stiff sand to clayey sand Yes No 12.7 0.107 0.154 1.44 No Yes No 1.44 Non-Liquefiable

0.8 48.3 1.2 2.5 115 96 96 96 - - - - - 0.44 1.70 82.2 0.39 1.70 82.2 0.39 82.2 0.00 11.0 93.2 6 - - Sandy silt to clayey silt 8 - - - Very stiff sand to clayey sand Yes No 12.7 0.086 0.183 2.12 No Yes No 2.12 Non-Liquefiable

1.0 54.2 1.4 2.6 115 115 115 115 - - - - - 0.42 1.70 92.2 0.37 1.70 92.2 0.37 92.2 0.00 10.2 102.3 6 - - Sandy silt to clayey silt 8 - - - Very stiff sand to clayey sand Yes No 12.7 0.072 0.224 3.12 No No No 3.12 Non-Liquefiable

1.1 47.5 1.5 3.1 115 134 134 134 - - - - - 0.42 1.70 80.8 0.37 1.70 80.8 0.37 80.8 0.00 17.9 98.7 6 - - Sandy silt to clayey silt 8 - - - Very stiff sand to clayey sand Yes No 25.4 0.123 0.194 1.57 No Yes No 1.57 Non-Liquefiable

1.3 38.5 1.4 3.6 115 153 153 153 - - - - - 0.43 1.70 65.5 0.37 1.70 65.5 0.37 65.5 0.00 20.1 85.6 5 - - Clayey silt to silty clay 8 - - - Very stiff sand to clayey sand Yes No 25.4 0.108 0.155 1.43 No Yes No 1.43 Non-Liquefiable

1.5 29.5 1.3 4.5 115 172 172 172 - - - - - 0.45 1.70 50.1 0.38 1.70 50.1 0.38 50.1 0.00 24.1 74.2 4 - - Silty clay to clay 8 - - - Very stiff sand to clayey sand Yes No 25.4 0.096 0.127 1.32 No Yes No 1.32 Non-Liquefiable

1.6 26.1 1.3 5.1 111 190 190 190 - - - - - 0.46 1.70 44.4 0.38 1.70 44.4 0.38 44.4 0.00 32.2 76.5 3 - - Clay 9 - - - Very stiff fine grained Yes No 38.0 0.130 0.120 0.92 Yes Yes No 0.92 Non-Liquefiable

1.8 28.1 1.4 5.1 111 208 208 208 - - - - - 0.45 1.70 47.8 0.37 1.70 47.8 0.37 47.8 0.00 30.6 78.4 3 - - Clay 9 - - - Very stiff fine grained Yes No 38.0 0.119 0.128 1.08 Yes Yes No 1.08 Non-Liquefiable

2.0 37.0 1.6 4.2 115 227 227 227 - - - - - 0.42 1.70 62.9 0.36 1.70 62.9 0.36 62.9 0.00 23.9 86.8 4 - - Silty clay to clay 8 - - - Very stiff sand to clayey sand Yes No 38.0 0.109 0.158 1.45 No Yes No 1.45 Non-Liquefiable

2.1 45.6 1.7 3.7 115 246 246 246 - - - - - 0.41 1.70 77.4 0.35 1.70 77.4 0.35 77.4 0.00 22.9 100.3 5 - - Clayey silt to silty clay 8 - - - Very stiff sand to clayey sand Yes No 50.6 0.134 0.197 1.47 No No No 1.47 Non-Liquefiable

2.3 49.1 1.7 3.5 115 265 265 265 - - - - - 0.40 1.70 83.5 0.35 1.70 83.5 0.35 83.5 0.00 21.2 104.7 5 - - Clayey silt to silty clay 8 - - - Very stiff sand to clayey sand Yes No 50.6 0.124 0.219 1.76 No No No 1.76 Non-Liquefiable

2.5 53.9 1.91 3.6 115 284 284 284 - - - - - 0.39 1.70 91.6 0.34 1.70 91.6 0.34 91.6 0.00 20.4 112.0 5 - - Clayey silt to silty clay 8 - - - Very stiff sand to clayey sand Yes No 50.6 0.116 0.257 2.22 No No No 2.22 Non-Liquefiable

2.6 63.5 2.2 3.5 115 303 303 303 - - - - - 0.38 1.70 108.0 0.33 1.70 108.0 0.33 108.0 0.00 21.8 129.8 6 - - Sandy silt to clayey silt 8 - - - Very stiff sand to clayey sand Yes No 63.0 0.135 0.354 2.62 No No No 2.62 Non-Liquefiable

2.8 67.3 2.3 3.4 115 321 321 321 - - - - - 0.37 1.70 114.4 0.33 1.70 114.4 0.33 114.4 0.00 20.8 135.3 6 - - Sandy silt to clayey silt 8 - - - Very stiff sand to clayey sand Yes No 63.0 0.127 0.401 3.14 No No No 3.14 Non-Liquefiable

3.0 62.1 2.3 3.7 115 340 340 340 - - - - - 0.37 1.70 105.5 0.33 1.70 105.5 0.33 105.5 0.00 22.0 127.5 5 - - Clayey silt to silty clay 8 - - - Very stiff sand to clayey sand Yes No 63.0 0.120 0.351 2.92 No No No 2.92 Non-Liquefiable

3.1 52.4 2.3 4.5 115 359 359 359 - - - - - 0.37 1.70 89.1 0.32 1.70 89.1 0.32 89.1 0.00 29.0 118.1 4 - - Silty clay to clay 8 - - - Very stiff sand to clayey sand Yes No 75.4 0.136 0.282 2.07 No No No 2.07 Non-Liquefiable

3.3 46.6 2.3 5.0 115 378 378 378 - - - - - 0.38 1.70 79.2 0.32 1.70 79.2 0.32 79.2 0.00 32.0 111.2 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 75.4 0.130 0.247 1.90 No No No 1.90 Non-Liquefiable

3.4 52.8 2.3 4.3 115 397 397 397 - - - - - 0.38 1.70 89.8 0.32 1.70 89.8 0.32 89.8 0.00 26.6 116.4 5 - - Clayey silt to silty clay 8 - - - Very stiff sand to clayey sand Yes No 75.4 0.124 0.281 2.27 No No No 2.27 Non-Liquefiable

3.6 48.0 2.2 4.5 115 416 416 416 - - - - - 0.38 1.70 81.6 0.33 1.70 81.6 0.33 81.6 0.00 29.4 111.0 4 - - Silty clay to clay 8 - - - Very stiff sand to clayey sand Yes No 87.7 0.137 0.242 1.76 No No No 1.76 Non-Liquefiable

3.8 42.7 2.0 4.6 115 435 435 435 - - - - - 0.39 1.70 72.6 0.34 1.70 72.6 0.34 72.6 0.00 29.6 102.2 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 87.7 0.131 0.203 1.55 No No No 1.55 Non-Liquefiable

3.9 39.7 1.8 4.6 115 453 453 453 - - - - - 0.40 1.70 67.5 0.34 1.70 67.4 0.34 67.4 0.00 28.8 96.2 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 87.7 0.126 0.182 1.45 No Yes No 1.45 Non-Liquefiable

4.1 38.0 1.7 4.5 115 472 472 472 - - - - - 0.41 1.70 64.7 0.35 1.69 64.3 0.35 64.3 0.00 29.4 93.7 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 100.0 0.138 0.168 1.22 Yes Yes No 1.22 Non-Liquefiable

4.3 34.1 1.6 4.8 115 491 491 491 - - - - - 0.42 1.70 58.0 0.36 1.68 57.4 0.36 57.4 0.00 31.1 88.5 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 100.0 0.132 0.151 1.14 Yes Yes No 1.14 Non-Liquefiable

4.4 28.8 1.5 5.3 111 509 509 509 - - - - - 0.44 1.70 48.9 0.37 1.68 48.4 0.37 48.4 0.00 31.8 80.3 3 - - Clay 9 - - - Very stiff fine grained Yes No 100.0 0.128 0.133 1.04 Yes Yes No 1.04 Non-Liquefiable

4.6 25.5 1.4 5.4 111 528 528 528 - - - - - 0.46 1.70 43.3 0.38 1.69 43.1 0.38 43.1 0.00 33.3 76.4 3 - - Clay 9 - - - Very stiff fine grained Yes No 112.2 0.138 0.120 0.87 Yes Yes No 0.87 Non-Liquefiable

4.8 24.4 1.4 5.6 111 546 546 546 - - - - - 0.46 1.70 41.5 0.38 1.68 40.9 0.38 40.9 0.00 32.7 73.6 3 - - Clay 9 - - - Very stiff fine grained Yes No 112.2 0.134 0.117 0.88 Yes Yes No 0.88 Non-Liquefiable

4.9 23.5 1.3 5.5 111 564 564 564 - - - - - 0.47 1.70 39.9 0.39 1.67 39.2 0.39 39.2 0.00 32.1 71.3 3 - - Clay 9 - - - Very stiff fine grained Yes No 112.2 0.129 0.112 0.86 Yes Yes No 0.86 Non-Liquefiable

5.1 22.4 1.2 5.4 111 582 582 582 - - - - - 0.48 1.70 38.1 0.40 1.67 37.4 0.40 37.4 0.00 33.3 70.7 3 - - Clay 9 - - - Very stiff fine grained Yes No 124.3 0.139 0.107 0.77 Yes Yes No 0.77 Non-Liquefiable

5.2 23.2 1.2 5.0 111 600 600 600 - - - - - 0.48 1.70 39.4 0.40 1.66 38.5 0.40 38.5 0.00 32.8 71.2 3 - - Clay 9 - - - Very stiff fine grained Yes No 124.3 0.135 0.105 0.78 Yes Yes No 0.78 Non-Liquefiable

5.4 24.5 1.1 4.6 115 619 619 619 - - - - - 0.48 1.70 41.6 0.40 1.64 40.2 0.40 40.2 0.00 29.3 69.5 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 124.3 0.130 0.105 0.80 Yes Yes No 0.80 Non-Liquefiable

5.6 25.2 1.1 4.6 115 638 638 638 - - - - - 0.48 1.70 42.9 0.40 1.62 40.9 0.40 40.9 0.00 30.0 70.9 4 - - Silty clay to clay 9 - - - Very stiff fine grained Yes No 136.3 0.139 0.106 0.76 Yes Yes No 0.76 Non-Liquefiable

5.7 26.2 1.1 4.3 115 657 657 657 - - - - - 0.48 1.70 44.6 0.40 1.60 42.0 0.40 42.0 0.00 28.1 70.1 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 136.3 0.135 0.106 0.79 Yes Yes No 0.79 Non-Liquefiable

5.9 24.2 1.2 4.9 111 675 675 675 - - - - - 0.48 1.70 41.1 0.40 1.59 38.4 0.40 38.4 0.00 31.4 69.8 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 136.3 0.131 0.104 0.79 Yes Yes No 0.79 Non-Liquefiable

6.1 23.4 1.2 5.3 111 693 693 693 - - - - - 0.48 1.70 39.8 0.40 1.57 36.7 0.40 36.7 0.00 33.4 70.0 3 - - Clay 9 - - - Very stiff fine grained Yes No 148.3 0.139 0.104 0.75 Yes Yes No 0.75 Non-Liquefiable

6.2 23.1 0.8 3.5 115 712 712 712 - - - - - 0.52 1.70 39.3 0.44 1.62 37.3 0.44 37.3 0.00 22.3 59.6 5 - - Clayey silt to silty clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 148.3 0.135 0.090 0.67 Yes Yes No 0.67 Non-Liquefiable

6.4 23.6 0.9 3.8 115 731 731 731 - - - - - 0.51 1.70 40.2 0.43 1.58 37.4 0.43 37.4 0.00 24.1 61.5 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 148.3 0.132 0.093 0.71 Yes Yes No 0.71 Non-Liquefiable

6.6 24.2 0.9 3.9 115 750 750 750 - - - - - 0.50 1.68 40.8 0.43 1.56 37.8 0.43 37.8 0.00 24.9 62.7 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 160.2 0.139 0.094 0.67 Yes Yes No 0.67 Non-Liquefiable

6.7 24.9 1.0 3.9 115 769 769 769 - - - - - 0.50 1.65 41.1 0.43 1.54 38.3 0.43 38.3 0.00 25.2 63.5 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 160.2 0.135 0.095 0.70 Yes Yes No 0.70 Non-Liquefiable

6.9 25.5 1.1 4.2 115 788 788 788 - - - - - 0.49 1.62 41.2 0.42 1.51 38.6 0.42 38.6 0.00 26.3 64.9 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 160.2 0.132 0.098 0.74 Yes Yes No 0.74 Non-Liquefiable

7.1 23.7 1.1 4.5 115 807 807 807 - - - - - 0.49 1.60 38.0 0.42 1.50 35.6 0.42 35.6 0.00 29.9 65.5 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 172.0 0.139 0.096 0.69 Yes Yes No 0.69 Non-Liquefiable

7.2 21.3 1.0 4.9 111 825 825 825 - - - - - 0.50 1.61 34.1 0.43 1.50 31.9 0.43 31.9 0.00 32.2 64.1 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 172.0 0.136 0.092 0.68 Yes Yes No 0.68 Non-Liquefiable

7.4 20.7 1.0 4.6 111 843 843 843 - - - - - 0.51 1.60 33.2 0.44 1.50 31.1 0.44 31.1 0.00 29.8 60.9 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 172.0 0.133 0.089 0.67 Yes Yes No 0.67 Non-Liquefiable

7.5 18.0 0.9 4.7 111 861 861 861 - - - - - 0.54 1.63 29.3 0.46 1.51 27.3 0.46 27.3 0.00 31.4 58.6 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 183.7 0.139 0.084 0.60 Yes Yes No 0.60 Non-Liquefiable

7.7 16.6 0.8 4.6 111 879 879 879 - - - - - 0.56 1.64 27.3 0.48 1.52 25.3 0.48 25.3 0.00 30.0 55.3 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 183.7 0.136 0.080 0.59 Yes Yes No 0.59 Non-Liquefiable

7.9 16.7 0.7 4.4 111 898 898 898 - - - - - 0.57 1.62 27.1 0.48 1.51 25.2 0.48 25.2 0.00 28.6 53.8 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 183.7 0.133 0.079 0.59 Yes Yes No 0.59 Non-Liquefiable

8.0 17.3 0.7 4.2 115 916 916 916 - - - - - 0.56 1.60 27.7 0.48 1.50 25.8 0.48 25.8 0.00 27.5 53.4 4 - - Silty clay to clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 195.4 0.139 0.078 0.57 Yes Yes No 0.57 Non-Liquefiable

8.2 17.4 0.8 4.7 111 935 935 935 - - - - - 0.55 1.57 27.3 0.47 1.47 25.6 0.47 25.6 0.00 30.9 56.5 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 195.4 0.136 0.081 0.60 Yes Yes No 0.60 Non-Liquefiable

8.4 19.1 0.9 4.5 111 953 953 953 - - - - - 0.53 1.53 29.2 0.46 1.45 27.6 0.46 27.6 0.00 29.2 56.8 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 195.4 0.133 0.083 0.62 Yes Yes No 0.62 Non-Liquefiable

8.5 18.2 0.9 4.8 111 971 971 971 - - - - - 0.54 1.52 27.6 0.47 1.44 26.1 0.47 26.1 0.00 31.8 58.0 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 207.0 0.139 0.082 0.60 Yes Yes No 0.60 Non-Liquefiable

8.7 17.9 0.8 4.6 111 989 989 989 - - - - - 0.54 1.51 27.1 0.47 1.43 25.7 0.47 25.7 0.00 30.3 56.0 3 - - Clay 4 - - - Silt mixtures - clayey silt to silty clay Yes No 207.0 0.136 0.081 0.59 Yes Yes No 0.59 Non-Liquefiable From Dissipation Testing
Typical Winter (February Mean)
Station:

CPT ID:

CPT Location: Levee Crest (5 feet from center towards landside) Earthquake Magnitude (Mw) =
Groundwater Depth bgs During Exploration (ft) =
PROJECT NAME:

LEVEE SEGMENT:

Design Groundwater Elevation (ft) =
Location (Crest/Landside/Waterside)
DWR Levee Geotechnical Evaluations Program
Normalization 1st Iteration

INPUT DATA FROM CPT

SOUNDING

OVERBURDEN
STRESS
DWR Urban Levee Geotechnical Evaluations Program (ULE)
Task Area:

Table 1: CPT Based Liquefaction-Triggering Analysis for ULE Errata to Equation (5) were published the Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Sep 2007. Page 1177.

1. Moss, R.E.S. , Seed, R.B., Kayen, R.E., Stewart, J.P., Der Kiureghian, A. and Cetin, K.O., 2006. "CPT-Based Probabilistic and Deterministic Assessment of in Situ Seismic Soil Liquefaction Potential". Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No. 8, August 2006, pp. 1032-1051, (doi 10.1061/(ASCE)1090-0241(2006)132:8(1032)).

Groundwater Elevation During Exploration (NAVD88) =

6. Robertson, P.K., and Wride (Fear), C.E., 1998. "Evaluating Cyclic Liquefaction Potential Using the Cone Penetration Test". Canadian Geotechnical Journal, 35, pp. 442–459.

Normalization 5th Iteration Normalization: Internal Code

2. Lunne, T., Robertson, P. K. and Powell, J.J.M., 1997. Cone Penetration Testing in Geotechnical Practice. Blackie Academic & Professional. London.

3. URS Corporation 2013. Guidance Document for Geotechnical Analysis, Urban Levee Geotechnical Evaluations Project, Version 14.

4. Seed, R.B., Cetin, K. O. Moss, R. E. S., Kammerer, A. M., Wu, J., Pestana, J. M., Riemer, M. F., Sancio, R.B., Bray, J. D., Kayen, R. E., Faris, A., 2003. "Recent Advances in Soil Liquefaction Engineering : A Unified and Consistent Framework". 26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Keynote Presentation, H.M.S. Queens Mary, Long Beach, Ca .

5. Bray, J.D., Sancio, R.B., 2006. "Assessment of the Liquefaction Susceptibility of Fine-Grained Soils". Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No. 9, September 2006, pp. 1165-1177.

Thin Layer
TIP RESISTANCE CORRECTIONS: THIN LAYER, NORMALIZATION, AND FINES FINAL LIQUEFACTION ASSESSMENT CPT-BASED SOIL BEHAVIOR Soil Behavior Type, SBT Normalized Soil Behavior Type, SBTn

LABORATORY TEST RESULTS LIQUEFACTION CRITERIA
Data Input By Analyst
Results of Analysis
Calculated Values
Total Number of Thin Layers (N) =
PROJECT NUMBER:

Reach ID:

Groundwater Depth bgs During Earthquake(ft) =
Return Period (Years) =
Peak Ground Acceleration (PHA, g) =
Ground Elevation (NAVD88) =
Enter thin layer depths and the corresponding average tip resistance representing thin layer and outside thin layer, and select Cthin Notes:
1- Thin layer correction can be only made for a standard cone (diameter = 1.4055") 2- Based on Reference 1, minimum tip resistance ratio (qcB)avg/(qcA)avg = 2, and maximum tip resistance ratio (qcB)avg/(qcA)avg = 10 are used 3- User can enter up to 30 thin layers
4- Interpolated Cthin is provided for maximum thin layer thickness of 2.4 feet (for (qcB)avg/(qcA)avg between 2 and 5) and 7.2 feet (for (qcB)avg/(qcA)avg between 5 and 10) 5- Cthin outside interpolation range can be selected by user (Figure 5, Reference 1) 6- Thin layer correction factor Cthin is capped at 1.8
User Error

1.4055 Warning 4 Alert
Layer NumberDepth to Top of LayerDepth to Bottom of LayerThin Layer Thickness, hAverage Tip Resistance in Thin Layer, (qcB)avrAverage Tip Resistance Outside Thin Layer, (qcA)avr(qcB)avg/(qcA)avgThin Layer Correction Factor, Cthin (Figure 5 - Digitized & Interpolated)Thin Layer Correction Factor, Cthin (Figure 5 - Selected by User)Corrected Tip Resistance for thin Layer, qc* Errors, Warnings and Alerts
Depth
Raw Tip Resistance, qc
Sleeve Friction, fsTotal Unit WeightSoil Behavior Type, SBTNormalized Soil Behavior Type, SBTn (-) (ft) (ft) (ft) (tsf) (tsf) (-) (-) (-) (tsf) (ft) (tsf) (tsf) (pcf) (-) (-) 1 11.0 12.5 1.5 80 20 4.0 1.38 1.38 110 0.7 45.3 0.9 118.0 7 8 2 15.0 16.0 1.0 210 70 3.0 1.47 1.47 309 0.8 48.3 1.2 115.0 6 8 3 22.5 24.0 1.5 256 120 2.1 1.23 1.23 315 1.0 54.2 1.4 115.0 6 8 4 34.5 36.9 2.4 100 40 2.5 1.11 1.11 111 1.1 47.5 1.5 115.0 6 8

1.3 38.5 1.4 115.058

1.5 29.5 1.3 115.048

1.6 26.1 1.3 111.039

1.8 28.1 1.4 111.039

2.0 37.0 1.6 115.048

2.1 45.6 1.7 115.058

2.3 49.1 1.7 115.058

2.5 53.9 1.9 115.058

2.6 63.5 2.2 115.0
68 2.8 67.3 2.3 115.068

3.0 62.1 2.3 115.058

3.1 52.4 2.3 115.048

3.3 46.6 2.3 115.049

3.4 52.8 2.3 115.058

3.6 48.0 2.2 115.048

3.8 42.7 2.0 115.049

3.9 39.7 1.8 115.049

4.1 38.0 1.7 115.049

4.3 34.1 1.6 115.049

4.4 28.8 1.5 111.039

4.6 25.5 1.4 111.039

4.8 24.4 1.4 111.039

4.9 23.5 1.3 111.039

5.1 22.4 1.2 111.039

5.2 23.2 1.2 111.039

5.4 24.5 1.1 115.049

5.6 25.2 1.1 115.049

5.7 26.2 1.1 115.044

5.9 24.2 1.2 111.034

6.1 23.4 1.2 111.039

6.2 23.1 0.8 115.0
5 4

6.4 23.6 0.9 115.044

6.6 24.2 0.9 115.044

6.7 24.9 1.0 115.044

6.9 25.5 1.1 115.044

7.1 23.7 1.1 115.044

SELECTED CPT DATA
Cone Diameter (inch) =
Total Number of Thin Layers (N) =

THIN LAYER CORRECTION
048
12 16
20 24
28 32
36 40
44 48
52 56
60 64
68 72
0 100 200 300 400 500 600
ft
Tip Resistance q
c, tsf
References:

1. 2.

3. 4.

Notes and Instructions:

3. Legend for Color Code
July, 2008
Developed by
Verified with
Verified by
Calculated Values
Date
Khaled Chowdhury, PE, GE and Adil Shah, PE
Contributors:

Version 1.1
Date July, 2012
Version 1.2
Updated by Gyeong-Taek Hong, Kanax Kanagalingam, Erik Julian Update approved by Khaled Chowdhury and Michael Hughes
Verified with MS Office Excel 2010

SPT BASED LIQUEFACTION ANALYSIS FOR ULE

DWR URBAN LEVEE GEOTECHNICAL EVALUATIONS PROGRAM (ULE)

6. The spreadsheet is built to automatically calculate CSR values based on the τmax values on the tabs Crest_Tau, Landside_Tau, and Waterside_Tau. The τmax values are given at 0.5 ft. intervals. The maximum depth for crest τmax = 140 feet, landside τmax = 120 feet, and waterside τmax = 100 feet.

15. Depth of Liquefaction evaluation should be in accordance with the current Guidance Document for the ULE program.

9. Sampler Codes : S = SPT Standard Sampler, SW = SPT Standard Sampler with Slot for Liner But Liner Not Used, SCAL = California Sampler with 2.4 inch I.D., MCAL = California Sampler with 2.0 inch I.D. (Mike Lubbers, 2006)
Data Input By Analyst
Less Likely Liquefiable
CSR Interpolation by
Detail Check by
Ahmed Bayoumi, PhD and Anthony Deus
Gyeong-Taek Hong, PhD, PE
Michael Luebbers, GE, PE
MS Office Excel 2003 SP2, Part of MS Office Standard Edition 2003 Likely Liquefiable

5. CRR values are calculated using Reference 1 and CSR values are calculated based on τmax values presented in Reference 2.

7. To select τmax values, enter the following (in Row 23, Column AC):
- For borings located water-ward of a point one-third up the waterside slope of the levee, enter "Waterside" - For borings located land-ward of a point one-third up the landside slope of the levee, enter "Landside" - For borings located within the region one-third up the water side slopes and including the crest, enter "Crest"

12. In the absence of laboratory data for fines content (FC), the spreadsheet estimates fines content as: FC = 35% for CL, ML, CL-ML, OL, CH, MH, OH ; FC = 12% for GM, GC, GC-GM, SM, SC, SC-SM ; FC = 8% for GW-GM, GW-GC, GPGM, GP-GC, SW-SM, SW-SC, SP-SM, SP-SC (average of range shown on DWR Soil and Rock Logging Manual v1.3) ; FC = 5% for GP, GW, SP, SW. Any soil type except these soil types will result in "Error in USCS". For FC < 5%, FC = 0% used in accordance with Reference 1.

13. Liquefaction susceptibilty of fine-grained soils is assessed based on laboratory data in Column AM ("PI <10, LL<35, and w > 0.8 LL? (Yes/No)"). For intermittently loaded levees, CL materials are not considered susceptible to liquefaction.

For frequently loaded levees, the Atterberg Limits criteria above apply to CL materials. Analysts need to manually enter whether fine-grained soil is susceptible to liquefaction in Column AN ("Liquefaction Susceptibility Based on Soil Type (Yes/No)") based on Column AM or evaluation of chacteristics based on soil deposits, in the absence of laboratory data.

Atterberg Limits data sould not be entered for coarse-grained soils.

14. The following equation was used to calculate the Sampler Correction, Cs for non standardized sampler configuration

11. Sampler Correction: For SW: Reference 1 was Used; For SCAL (Sampler Correction = 0.65) and MCAL (sampler correction = 0.8): Notes from Reference 4 (Section 5.4.5) and local practice info used.

4. The spreadsheet estimates the Factors of Safety against liquefaction in accordance with the procedure described in Reference 1. In accordance with Reference 2, FSL <1 is considered "Likely Liquefiable" and 1<FSL <1.25 is considered "Less Likely Liquefiable". User shall be responsible for interpretation of the FSL results.

Non-Liquefiable

10. Depth to sample is considered the distance between top of boring to the depth of the N value.

Cetin, K.O., et al, 2004. Standard Penetration Test-Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Potential. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 130, No. 12, 1313-1340 and Discussions and Closures (May, 2006)
Seed, R.B., et al, 2003, Recent Advances in Soil Liquefaction Engineering : A Unified and Consistent Framework. 26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Keynote Presentation, H.M.S. Queens Mary, Long Beach, Ca (not used for spreadsheet equations)
Southern California Earthquake Center, University of Southern California, Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and Mitigating Liquefaction in California (1999). (used only for guidance on MCAL and SCAL sampler correction)
URS Corporation 2013. Guidance Document for Geotechnical Analysis , Urban Levee Geotechnical Evaluations Project Version 14

1. The user should understand the methodology and assumptions presented in the references before using this spreadsheet.

8. In the normal distribution function of CRR, a Probability (PL) value of 15% was used in accordance with References 1 and 3.

Results of Analysis
Date January, 2014
Version 1.3
Updated by Erik Julian, Bryan Burnitt, Kanax Kanagalingam Update approved by Khaled Chowdhury
Verified with MS Office Excel 2010
100

01.0(1CCCN MAX(10, )))N MIN(30, 1 Cs EBR1 1 ⋅+⋅⋅⋅⋅ +=
C:\Users\KC_Fuerstenberger\Desktop\Copy of SPT LiquefactionV1 3 (Less Likely)SPT Based Liquefaction 8/6/2014
Notes:

SPT-BASED LIQUEFACTION ANALYSIS 1. Refer to the Verification and Read Me tabs for further notes and instructions on using this spreadsheet.

References: 2. The "N60" values shown in this spreadsheet include corrections for hammer efficiency, borehole diameter, sampler type, and rod length (i.e., N60=NfieldCECBCSCR). These "N60" values are

1. Cetin, K.O., et al, 2004. Standard Penetration Test-Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Potential. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 130, No. 12, 1313-1340. and Discussions and Closures (May, 2006) not directly comparable to the "N60(ASTM)" values shown on boring logs and stick figures (on cross-sections and profiles), which are only corrected for hammer efficiency (i.e., N60(ASTM)=NfieldC

2. URS Corporation 2012. Guidance Document for Geotechnical Analysis , Urban Levee Geotechnical Evaluations Program Rev. 12. 3. As applicable, blow counts for Standard and Modified California samples may be presented below. Please note that on boring logs and stick figures (on cross-sections and profiles),

3. Seed, R.B., et al, 2003. Recent Advances in Soil Liquefaction Engineering : A Unified and Consistent Framework . 26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Keynote Presentation, H.M.S. Queens Mary, Long Beach, Ca. "N60(ASTM)" values are not shown for Standard and Modified California samples.

4. Southern California Earthquake Center, University of Southern California, Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and Mitigating Liquefaction in California (1999). (used only for guidance on MCAL and SCAL sampler correction) Cell color definitions:

Analysis By: Date:

Check By: Date:

39.2 Note: Intermittently (I) or Frequently (F) Loaded Levee = I Earthquake Information:

Groundwater Elev. During Drilling (ft.) = 7.4 Note: Groundwater Depth Below GS During Drilling (ft.) = 31.8 Hammer Type = Automatic Return Period (years) = 200 PHA (g) = 0.15 Analyzed Groundwater Elevation (ft.)= 12.5 Note: Analyzed Groundwater Depth Below GS (ft.) = 26.7 Energy Ratio = 84 Mw = 6.5 Location = Crest Enter: Crest, Landside, or Waterside Sample ID Depth to Sample (ft.) NfieldUSCS ClassificationUnit Weight (pcf)Total Overburden Pressure, σv (psf)Effective Overburden Pressure During Drilling, σv' (psf)Effective Overburden Pressure During Earthquake, σv' (psf)Overburden Correction Factor, CNCorrection for Hammer Energy Efficiency, CEDrilling MethodBorehole Diameter (inches)Correction for Borehole Diameter, CBSampler Code(S, SW, SCAL, MCAL)N1 for Sampler Correction Only(for SW sampler)Sampler Correction, Cs (for SW Sampler only)Sampler Correction for Analysis, CsStick Up (Protrusion) Rod Length Above Ground (feet)Rod Length (m)Rod Length Correction Factor, CRN60N1,60Fines Content (%)Fines Content for Analysis (%)Correction Factor for Fine Content, CfinesN1,60,CSCyclic Resistance Ratio, CRR τmax (psf)
Cyclic Stress Ratio, CSRFactor of Safety, FSL
FSL < 1.25 (Yes/No)Below Analyzed Ground water Level (Yes/No)N1,60,CS<23 (Yes/No) USCS Classification
Liquid Limit, LL (%)(Enter number only)Plasticity Index, PI (%)(Enter number only)Water Content, w (%)(Enter number only)NP from Atterberg Limits test (Yes/Blank)Is PI<10, LL<35, w>0.8LL?Liquefaction Susceptibility Based on Soil Type (Yes/No)Final Assessment(Yes/No)(Based on Columns AE, AF,AG, and AN)Factor of Safety, FSLComment(Likely Liquefiablefor FSL≤1;Less Likely Liquefiable for 1.0<FSL<1.25;Non-Liquefiable for FSL≥1.25) 3 5 4 SM 115 575 575 575 1.6 1.4 H 7 1.10 S 6 1.10 1.00 7 3.4 0.75 5 7 20 20 1.2 9 0.126 117.8 0.133 0.95 Yes No Yes SM - Yes No 0.95 Non-Liquefiable Non-Liquefiable. Sample is above the groundwater surface. 5 10 6 ML 120 1175 1175 1175 1.3 1.4 H 7 1.10 S 8 1.11 1.00 7 4.9 0.83 8 10 59 35 1.3 13 0.141 228.7 0.126 1.11 Yes No Yes ML - Yes No 1.11 Non-Liquefiable Non-Liquefiable. Sample is above the groundwater surface. 7 15 6 SM 115 1750 1750 1750 1.1 1.4 H 7 1.10 S 6 1.10 1.00 7 6.4 0.90 8 9 25 25 1.2 11 0.107 303.8 0.113 0.95 Yes No Yes SM - Yes No 0.95 Non-Liquefiable Non-Liquefiable. Sample is above the groundwater surface. 9 20 9 SM 125 2375 2375 2375 0.9 1.4 H 7 1.10 S 8 1.13 1.00 7 7.9 0.94 13 12 12 1.1 13 0.115 357.5 0.098 1.18 Yes No Yes SM - Yes No 1.18 Non-Liquefiable Non-Liquefiable. Sample is above the groundwater surface. 12 28 10 CH 125 3375 3375 3294 0.8 1.4 H 7 1.10 S 8 1.13 1.00 7 10.4 0.97 15 12 35 1.3 15 0.120 423.5 0.084 1.44 No Yes Yes CH 51 24 No No No 1.44 Non-Liquefiable Non-Liquefiable. Not susceptible to liquefaction. 15 33 6 ML 120 3975 3900 3582 0.7 1.4 M 5 1.02 S 4 1.10 1.00 7 11.9 0.98 8 6 74 35 1.4 9 0.074 461.0 0.084 0.88 Yes Yes Yes ML Yes Yes Yes Yes 0.88 Likely Liquefiable Likely Liquefiable. FSL<1.0. 17 35 5 ML 120 4215 4015 3697 0.7 1.4 M 5 1.02 S 4 1.10 1.00 7 12.5 0.99 7 5 59 35 1.5 7 0.067 474.9 0.083 0.80 Yes Yes Yes ML - Yes Yes 0.80 Likely Liquefiable Likely Liquefiable. FSL<1.0. 19 40 8 ML 125 4840 4328 4010 0.7 1.4 M 5 1.02 S 5 1.10 1.00 7 14.0 0.99 11 8 35 1.4 11 0.082 509.8 0.083 0.99 Yes Yes Yes ML - Yes Yes 0.99 Likely Liquefiable Likely Liquefiable. FSL<1.0. 21 45 10 SM 125 5465 4641 4323 0.7 1.4 M 5 1.02 S 7 1.10 1.00 7 15.5 0.99 14 9 38 35 1.3 12 0.093 542.8 0.082 1.14 Yes Yes Yes SM 31 Yes Yes Yes Yes 1.14 Less Likely Liquefiable Less Likely Liquefiable. 1.0<FSL<1.25. 23 50 0 SM 115 6040 4904 4586 0.6 1.4 M 5 1.02 S 0 1.10 1.00 7 17.1 1.00 0 0 51 35 193.7 2 0.041 574.1 0.081 0.50 Yes Yes Yes SM - Yes Yes 0.50 Likely Liquefiable Likely Liquefiable. FSL<1.0. 25 55 20 SP-SM 125 6665 5217 4899 0.6 1.4 M 5 1.02 S 12 1.20 1.00 7 18.6 1.00 29 18 10 10 1.1 19 0.145 603.8 0.080 1.81 No Yes Yes SP-SM - Yes No 1.81 Non-Liquefiable Non-Liquefiable. FSL≥1.25. 27 60 14 SP-SM 125 7290 5530 5212 0.6 1.4 M 5 1.02 S 8 1.13 1.00 7 20.1 1.00 20 12 8 1.1 13 0.091 631.9 0.079 1.15 Yes Yes Yes SP-SM - Yes Yes 1.15 Less Likely Liquefiable Less Likely Liquefiable. 1.0<FSL<1.25. 29 65 16 SP-SM 125 7915 5843 5525 0.6 1.4 M 5 1.02 S 9 1.15 1.00 7 21.6 1.00 23 13 8 8 1.1 14 0.099 657.2 0.077 1.28 No Yes Yes SP-SM - Yes No 1.28 Non-Liquefiable Non-Liquefiable. FSL≥1.25. 31 70 23 SP-SM 130 8565 6181 5863 0.6 1.4 M 5 1.02 S 13 1.21 1.00 7 23.2 1.00 33 19 8 1.1 20 0.147 682.4 0.076 1.94 No Yes Yes SP-SM - Yes No 1.94 Non-Liquefiable Non-Liquefiable. FSL≥1.25. 33 75 32 SP-SM 130 9215 6519 6201 0.6 1.4 M 5 1.02 S 18 1.30 1.00 7 24.7 1.00 46 25 8 1.0 27 0.242 707.7 0.074 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Non-Liquefiable. FSL≥1.25. Sample is below liquefaction assessment zone (>50' below LS toe).
35 80 28 SP-SM 130 9865 6857 6539 0.5 1.4 M 5 1.02 S 15 1.25 1.00 7 26.2 1.00 40 22 9 9 1.1 23 0.181 732.9 0.073 2.48 No Yes Yes SP-SM - Yes No 2.48 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 37 85 29 SP-SM 130 10515 7195 6877 0.5 1.4 M 5 1.02 S 15 1.25 1.00 7 27.7 1.00 41 22 8 1.1 23 0.180 755.7 0.071 2.52 No Yes Yes SP-SM - Yes No 2.52 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 39 90 18 SP-SM 125 11140 7508 7190 0.5 1.4 M 5 1.02 S 9 1.15 1.00 7 29.3 1.00 26 13 9 9 1.1 14 0.092 778.5 0.070 1.31 No Yes Yes SP-SM - Yes No 1.31 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 41 95 69 GP-GM 130 11790 7846 7528 0.5 1.4 M 5 1.02 S 35 1.30 1.00 7 30.8 1.00 99 50 8 1.0 52 1.524 801.4 0.069 3.00 No Yes No GP-GM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 42 100 48 GP-GM 130 12440 8184 7866 0.5 1.4 M 5 1.02 S 24 1.30 1.00 7 32.3 1.00 69 34 8 1.0 35 0.440 824.2 0.068 3.00 No Yes No GP-GM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 43 105 74 GP-GM 130 13090 8522 8204 0.5 1.4 M 5 1.02 S 36 1.30 1.00 7 33.8 1.00 106 51 8 1.0 53 1.664 847.0 0.067 3.00 No Yes No GP-GM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 44 110 55 SP-SM 130 13740 8860 8542 0.5 1.4 M 5 1.02 S 26 1.30 1.00 7 35.4 1.00 79 37 13 13 1.1 40 0.605 869.8 0.066 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 45 115 120 SP-SM 130 14390 9198 8880 0.5 1.4 M 5 1.02 S 56 1.30 1.00 7 36.9 1.00 171 80 8 1.0 83 15.058 892.6 0.065 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 46 120 51 SP-SM 130 15040 9536 9218 0.5 1.4 M 5 1.02 S 23 1.30 1.00 7 38.4 1.00 73 33 9 9 1.0 35 0.410 915.5 0.065 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 47 125 69 SP-SM 130 15690 9874 9556 0.5 1.4 M 5 1.02 S 31 1.30 1.00 7 39.9 1.00 99 44 8 1.0 46 0.938 938.3 0.064 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 48 130 112 SP-SM 130 16340 10212 9894 0.4 1.4 M 5 1.02 S 50 1.30 1.00 7 41.5 1.00 160 71 9 9 1.0 74 7.388 961.1 0.063 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 49 135 47 SP-SM 130 16990 10550 10232 0.4 1.4 M 5 1.02 S 20 1.30 1.00 7 43.0 1.00 67 29 8 1.0 31 0.285 983.9 0.063 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe). 50 135 83 SP-SM 130 16990 10550 10232 0.4 1.4 M 5 1.02 S 36 1.30 1.00 7 43.0 1.00 119 52 8 1.0 54 1.616 983.9 0.063 3.00 No Yes No SP-SM - Yes No 3.00 Non-Liquefiable Below liquefaction assessment zone (>50' below LS toe).

DWR Urban Levee Geotechnical Evaluations Program (ULE)
Reach ID:

PROJECT NAME:

Table 1: Liquefaction-Triggering Analysis for ULE
Task Area: Sacramento River
LEVEE SEGMENT:

Data Input By Analyst
Results of Analysis
Avg. Winter WSE
Ground Elevation (ft.)=
Station:

PROJECT NUMBER:

Boring Location
(Crest/Landside/Waterside, and
distance from Crest/Landside
toe/Waterside toe)
Lab Test Results for Fine-Grained Soils
Crest
Boring ID: Likely Liquefiable
Conclusions and Comments
Liquefaction Assessment
Calculated Values
Non-Liquefiable
Less Likely Liquefiable

APPENDIX K

APPENDIX K
The Development of a 200-year Return
Period Seismic Hazard Map for the
Urban Levee Evaluations Project Region

URS Corporation
2870 Gateway Oaks Drive, Suite 150
Sacramento, CA 95833
Tel: 916.679.2000
Fax: 916.679.2900
Memorandum
Contract 4600008101

Page 1 of 6 ends

Sacramento City CouncilOctober 21, 2025

Sacramento City Council
October 21, 2025