Agenda packet — Coachella City Council, January 28, 2026 (part 9 of 11)

Item 33.
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AB C D

RCFCD SYNTHETIC UNIT HYDROGRAPH

DATA INPUT SHEET
WORKSHEET PREPARED BY: JAMES R. BAZUA, P.E.

PROJECT NAME CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB #
CONCENTRATION POINT DESIGNATION 1
AREA DESIGNATION SUBAREA 1

TRIBUTARY AREAS ACRES

COMMERCIAL
PAVING/HARDSCAPE 1.18
SF - 1 ACRE
SF - 1/2 ACRE
SF - 1/4 ACRE

MF - CONDOMINIUMS

MF - APARTMENTS

MOBILE HOME PARK
LANDSCAPING 0.83

RETENTION BASIN

GOLF COURSE

MOUNTAINOUS
LOW LOSS RATE (PERCENT) 90%
LENGTH OF WATERCOURSE (L) 1000
LENGTH TO POINT OPPOSITE CENTROID (Lca) 15
ELEVATION OF HEADWATER 471.5
ELEVATION OF CONCENTRATION POINT 468.8
AVERAGE MANNINGS 'N' VALUE 0.02
STORM FREQUENCY (YEAR) 100

POINT RAIN
3-HOUR 2.12
6-HOUR 2.78
24-HOUR 4.47
BASIN CHARACTERISTICS: ELEVATION AREA
465 3025
466 3700
467 4430
468 5215
468.5 5630
PERCOLATION RATE (in/hr) 0.67

DRYWELL DATA

NUMBER USED
PERCOLATION RATE (cfs)

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Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT BASIC DATA CALCULATION FORM JOB # 0
SHORTCUT METHOD BY ES R. BAZUA, P.E. DATE 1/17/2025
[1] SOURCE
[2] FREQUENCY-YEARS 100
[3] DURATION:
[4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]

POINT AREA AVERAGE POINT AREA AVERAGE POINT AREA AVERAGE

RAIN POINT RAIN POINT RAIN POINT

INCHES RAIN INCHES RAIN INCHES RAIN
(Plate E-5.2) INCHES (Plate E-5.4) INCHES (Plate E-5.6) INCHES

2.12 2.010 1.00 2.12 2.78 2.010 1.00 2.78 4.47 2.010 1.00 4.47

0.00 0.00 0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00
SUM [5] 2.01 SUM [7] 2.12 SUM [9] 2.01 SUM [11] 2.78 SUM [13] 2.01 SUM [15] 4.47 [16] AREA ADJ FACTOR 1.000 1.000 1.000
[17] ADJ AVG POINT RAIN 2.12 2.78 4.47
DURATION 3-HOUR 6-HOUR 24-HOUR
EFFECTIVE RAIN (in) 1.39 1.40 1.43
FLOOD VOLUME (cu-ft) 10,165 10,196 10,445
(acre-ft) 0.23 0.23 0.24
REQUIRED STORAGE (cu-ft) 9,580 9,148 8,100
(acre-ft) 0.22 0.21 0.19
PEAK FLOW (cfs) 3.70 3.26 0.80
MAXIMUM WSEL (ft) 467.45 467.36 467.13

0.189

15.00 0.000
[12] S^0.5
[13] L*LCA/S^0.5
[14] AVERAGE MANNINGS 'N'
[10] H-FEET 2.7
[11] S-FEET/MILE

PHYSICAL DATA

RAINFALL DATA
[1] CONCENTRATION POINT 1
SUBAREA 1

2.010
1000

0.003
471.5
468.8

0.02 1.0

1.0 2.0

14.3 3.78

0.02 6-HOURS
[6] La-FEET
[7] La-MILES
[8] ELEVATION OF HEADWATER
[9] ELEVATION OF CONCENTRATION POINT
[2] AREA DESIGNATION
[3] AREA - ACRES
[4] L-FEET
[5] L-MILES
5 24-HOURS
[15] LAG TIME-HOURS
[16] LAG TIME-MINUTES

0.05 STORM EVENT SUMMARY
[17] 100% OF LAG-MINUTES
[18] 200% OF LAG-MINUTES
[24] TOTAL PERCOLATION RATE (cfs)
[19] UNIT TIME-MINUTES (100%-200% OF LAG)
3-HOURS
Plate E-2.1

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Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT CALHOUN AT AVENUE 49 - 100 YEAR EVENT CONCENTRATION POINT: 1BY MES R. BAZUA, P.E. DATE 1/17/2025

ADJUSTED LOSS RATE

SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AVERAGE

GROUP NUMBER AREA PERCENT INFILTRATION ADJUSTED

INFILTRATION OF AREA RATE INFILTRATION

RATE IMPERVIOUS RATE
(in/hr) (in/hr) (in/hr)
[Plate C-1] [Plate E-6.1] [Plate E-6.2] [Plate E-6.3]
B 56 0.52 90% 0.10 0.00 0.000 0.0000
B 56 0.52 100% 0.05 1.18 0.587 0.0305
B 56 0.52 20% 0.43 0.00 0.000 0.0000B 56 0.52 40% 0.33 0.00 0.000 0.0000B 56 0.52 50% 0.29 0.00 0.000 0.0000B 56 0.52 65% 0.22 0.00 0.000 0.0000B 56 0.52 80% 0.15 0.00 0.000 0.0000B 56 0.52 75% 0.17 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.83 0.413 0.2147B 56 0.52 0% 0.52 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.00 0.000 0.0000 D 93 0.95 90% 0.18 0.00 0.000 0.0000

0.00 0.000 0.0000

0.00 0.000 0.0000
SUM 2.01 SUM 0.2453
VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY)Fm= 0.122626866C= 0.00227Ft=C(24-(T/60))^1.55 = 0.00227 0.12 in/hr LOW LOSS RATE (80-90 PERCENT) = 90%Where:T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 +

LAND USE

COMMERCIAL

PAVING/HARDSCAPE
SF - 1 ACRE
SF - 1/2 ACRESF - 1/4 ACRE
MF - COND0MINIUMS

MF - APARTMENTS

MOBILE HOME PARKS

LANDSCAPING

RETENTION BASINS

GOLF COURSE

MOUNTAINOUS
Plate E-2.1

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Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 3 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: MES R. BAZUA, DATE 1/17/2025
DRAINAGE AREA-ACRES 2.01
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 1.00
UNIT TIME-PERCENT OF LAG 502.5
TOTAL ADJUSTED STORM RAIN-INCHES 2.12
CONSTANT LOSS RATE-in/hr 0.25
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.05 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 1.3 0.331 0.25 0.30 0.09 0.17 37.46
2 10 0.17 1.3 0.331 0.25 0.30 0.09 0.17 37.46
3 15 0.25 1.1 0.280 0.25 0.25 0.03 0.07 6.78
4 20 0.33 1.5 0.382 0.25 0.34 0.14 0.27 68.14
5 25 0.42 1.5 0.382 0.25 0.34 0.14 0.27 68.14
6 30 0.50 1.8 0.458 0.25 0.41 0.21 0.43 114.16
7 35 0.58 1.5 0.382 0.25 0.34 0.14 0.27 68.14
8 40 0.67 1.8 0.458 0.25 0.41 0.21 0.43 114.16
9 45 0.75 1.8 0.458 0.25 0.41 0.21 0.43 114.16
10 50 0.83 1.5 0.382 0.25 0.34 0.14 0.27 68.14
11 55 0.92 1.6 0.407 0.25 0.37 0.16 0.33 83.48
12 60 1.00 1.8 0.458 0.25 0.41 0.21 0.43 114.16
13 65 1.08 2.2 0.560 0.25 0.50 0.31 0.63 175.52
14 70 1.17 2.2 0.560 0.25 0.50 0.31 0.63 175.52
15 75 1.25 2.2 0.560 0.25 0.50 0.31 0.63 175.52
16 80 1.33 2.0 0.509 0.25 0.46 0.26 0.53 144.84
17 85 1.42 2.6 0.661 0.25 0.60 0.42 0.84 236.89
18 90 1.50 2.7 0.687 0.25 0.62 0.44 0.89 252.23
19 95 1.58 2.4 0.611 0.25 0.55 0.37 0.73 206.21
20 100 1.67 2.7 0.687 0.25 0.62 0.44 0.89 252.23
21 105 1.75 3.3 0.840 0.25 0.76 0.59 1.19 344.27
22 110 1.83 3.1 0.789 0.25 0.71 0.54 1.09 313.59
23 115 1.92 2.9 0.738 0.25 0.66 0.49 0.99 282.91
24 120 2.00 3.0 0.763 0.25 0.69 0.52 1.04 298.25
25 125 2.08 3.1 0.789 0.25 0.71 0.54 1.09 313.59
26 130 2.17 4.2 1.068 0.25 0.96 0.82 1.65 482.33
27 135 2.25 5.0 1.272 0.25 1.14 1.03 2.06 605.05
28 140 2.33 3.5 0.890 0.25 0.80 0.65 1.30 374.95
29 145 2.42 6.8 1.730 0.25 1.56 1.48 2.98 881.18
30 150 2.50 7.3 1.857 0.25 1.67 1.61 3.24 957.88
31 155 2.58 8.2 2.086 0.25 1.88 1.84 3.70 1095.94
32 160 2.67 5.9 1.501 0.25 1.35 1.26 2.52 743.12
33 165 2.75 2.0 0.509 0.25 0.46 0.26 0.53 144.84
34 170 2.83 1.8 0.458 0.25 0.41 0.21 0.43 114.16
35 175 2.92 1.8 0.458 0.25 0.41 0.21 0.43 114.16
36 180 3.00 0.6 0.153 0.25 0.14 0.02 0.03 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.39
FLOOD VOLUME (acft) 0.23
FLOOD VOLUME (cuft) 10165.45
REQUIRED STORAGE (acft) 0.22
REQUIRED STORAGE (cuft) 9579.59
PEAK FLOW RATE (cfs) 3.70
Loss Rate
in/hr
Time

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

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Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 6 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 2.01
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 1.00
UNIT TIME-PERCENT OF LAG 502.5
TOTAL ADJUSTED STORM RAIN-INCHES 2.78
CONSTANT LOSS RATE-in/hr 0.245
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.05 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 0.5 0.167 0.25 0.15 0.02 0.03 0.00
2 10 0.17 0.6 0.200 0.25 0.18 0.02 0.04 0.00
3 15 0.25 0.6 0.200 0.25 0.18 0.02 0.04 0.00
4 20 0.33 0.6 0.200 0.25 0.18 0.02 0.04 0.00
5 25 0.42 0.6 0.200 0.25 0.18 0.02 0.04 0.00
6 30 0.50 0.7 0.234 0.25 0.21 0.02 0.05 0.01
7 35 0.58 0.7 0.234 0.25 0.21 0.02 0.05 0.01
8 40 0.67 0.7 0.234 0.25 0.21 0.02 0.05 0.01
9 45 0.75 0.7 0.234 0.25 0.21 0.02 0.05 0.01
10 50 0.83 0.7 0.234 0.25 0.21 0.02 0.05 0.01
11 55 0.92 0.7 0.234 0.25 0.21 0.02 0.05 0.01
12 60 1.00 0.8 0.267 0.25 0.24 0.02 0.04 0.00
13 65 1.08 0.8 0.267 0.25 0.24 0.02 0.04 0.00
14 70 1.17 0.8 0.267 0.25 0.24 0.02 0.04 0.00
15 75 1.25 0.8 0.267 0.25 0.24 0.02 0.04 0.00
16 80 1.33 0.8 0.267 0.25 0.24 0.02 0.04 0.00
17 85 1.42 0.8 0.267 0.25 0.24 0.02 0.04 0.00
18 90 1.50 0.8 0.267 0.25 0.24 0.02 0.04 0.00
19 95 1.58 0.8 0.267 0.25 0.24 0.02 0.04 0.00
20 100 1.67 0.8 0.267 0.25 0.24 0.02 0.04 0.00
21 105 1.75 0.8 0.267 0.25 0.24 0.02 0.04 0.00
22 110 1.83 0.8 0.267 0.25 0.24 0.02 0.04 0.00
23 115 1.92 0.8 0.267 0.25 0.24 0.02 0.04 0.00
24 120 2.00 0.9 0.300 0.25 0.27 0.05 0.11 19.08
25 125 2.08 0.8 0.267 0.25 0.24 0.02 0.04 0.00
26 130 2.17 0.9 0.300 0.25 0.27 0.05 0.11 19.08
27 135 2.25 0.9 0.300 0.25 0.27 0.05 0.11 19.08
28 140 2.33 0.9 0.300 0.25 0.27 0.05 0.11 19.08
29 145 2.42 0.9 0.300 0.25 0.27 0.05 0.11 19.08
30 150 2.50 0.9 0.300 0.25 0.27 0.05 0.11 19.08
31 155 2.58 0.9 0.300 0.25 0.27 0.05 0.11 19.08
32 160 2.67 0.9 0.300 0.25 0.27 0.05 0.11 19.08
33 165 2.75 1.0 0.334 0.25 0.30 0.09 0.18 39.20
34 170 2.83 1.0 0.334 0.25 0.30 0.09 0.18 39.20
35 175 2.92 1.0 0.334 0.25 0.30 0.09 0.18 39.20
36 180 3.00 1.0 0.334 0.25 0.30 0.09 0.18 39.20
37 185 3.08 1.0 0.334 0.25 0.30 0.09 0.18 39.20
38 190 3.17 1.1 0.367 0.25 0.33 0.12 0.24 59.31
39 195 3.25 1.1 0.367 0.25 0.33 0.12 0.24 59.31
40 200 3.33 1.1 0.367 0.25 0.33 0.12 0.24 59.31
41 205 3.42 1.2 0.400 0.25 0.36 0.16 0.31 79.43
42 210 3.50 1.3 0.434 0.25 0.39 0.19 0.38 99.55
43 215 3.58 1.4 0.467 0.25 0.42 0.22 0.45 119.66
44 220 3.67 1.4 0.467 0.25 0.42 0.22 0.45 119.66
45 225 3.75 1.5 0.500 0.25 0.45 0.26 0.51 139.78
46 230 3.83 1.5 0.500 0.25 0.45 0.26 0.51 139.78
47 235 3.92 1.6 0.534 0.25 0.48 0.29 0.58 159.89
48 240 4.00 1.6 0.534 0.25 0.48 0.29 0.58 159.89
49 245 4.08 1.7 0.567 0.25 0.51 0.32 0.65 180.01
50 250 4.17 1.8 0.600 0.25 0.54 0.36 0.71 200.13
51 255 4.25 1.9 0.634 0.25 0.57 0.39 0.78 220.24
52 260 4.33 2.0 0.667 0.25 0.60 0.42 0.85 240.36
53 265 4.42 2.1 0.701 0.25 0.63 0.46 0.92 260.48
54 270 4.50 2.1 0.701 0.25 0.63 0.46 0.92 260.48
55 275 4.58 2.2 0.734 0.25 0.66 0.49 0.98 280.59
56 280 4.67 2.3 0.767 0.25 0.69 0.52 1.05 300.71

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
Plate E-2.2

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Item 33.

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
57 285 4.75 2.4 0.801 0.25 0.72 0.56 1.12 320.82
58 290 4.83 2.4 0.801 0.25 0.72 0.56 1.12 320.82
59 295 4.92 2.5 0.834 0.25 0.75 0.59 1.18 340.94
60 300 5.00 2.6 0.867 0.25 0.78 0.62 1.25 361.06
61 305 5.08 3.1 1.034 0.25 0.93 0.79 1.59 461.64
62 310 5.17 3.6 1.201 0.25 1.08 0.96 1.92 562.22
63 315 5.25 3.9 1.301 0.25 1.17 1.06 2.12 622.56
64 320 5.33 4.2 1.401 0.25 1.26 1.16 2.32 682.91
65 325 5.42 4.7 1.568 0.25 1.41 1.32 2.66 783.49
66 330 5.50 5.6 1.868 0.25 1.68 1.62 3.26 964.54
67 335 5.58 1.9 0.634 0.25 0.57 0.39 0.78 220.24
68 340 5.67 0.9 0.300 0.25 0.27 0.05 0.11 19.08
69 345 5.75 0.6 0.200 0.25 0.18 0.02 0.04 0.00
70 350 5.83 0.5 0.167 0.25 0.15 0.02 0.03 0.00
71 355 5.92 0.3 0.100 0.25 0.09 0.01 0.02 0.00
72 360 6.00 0.2 0.067 0.25 0.06 0.01 0.01 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.40
FLOOD VOLUME (acft) 0.23
FLOOD VOLUME (cuft) 10195.68
REQUIRED STORAGE (acft) 0.21
REQUIRED STORAGE (cuft) 9147.59
PEAK FLOW RATE (cfs) 3.26
Plate E-2.2

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Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 24 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 2.010 CONSTANT LOSS RATE-in/hr n/a
UNIT TIME-MINUTES 15 VARIABLE LOSS RATE (AVG) in/hr 0.2453 LAG TIME - MINUTES 1.00 MINIMUM LOSS RATE (for var. loss) - in/hr 0.123 UNIT TIME-PERCENT OF LAG 1507.5 LOW LOSS RATE - DECIMAL 0.90 TOTAL ADJUSTED STORM RAIN-INCHES 4.47 C 0.00227
PERCOLATION RATE (cfs) 0.05
Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 15 0.25 0.2 0.036 0.433 0.032 0.004 0.01 0.00
2 30 0.50 0.3 0.054 0.428 0.048 0.005 0.01 0.00
3 45 0.75 0.3 0.054 0.423 0.048 0.005 0.01 0.00
4 60 1.00 0.4 0.072 0.418 0.064 0.007 0.01 0.00
5 75 1.25 0.3 0.054 0.413 0.048 0.005 0.01 0.00
6 90 1.50 0.3 0.054 0.408 0.048 0.005 0.01 0.00
7 105 1.75 0.3 0.054 0.403 0.048 0.005 0.01 0.00
8 120 2.00 0.4 0.072 0.399 0.064 0.007 0.01 0.00
9 135 2.25 0.4 0.072 0.394 0.064 0.007 0.01 0.00
10 150 2.50 0.4 0.072 0.389 0.064 0.007 0.01 0.00
11 165 2.75 0.5 0.089 0.384 0.080 0.009 0.02 0.00
12 180 3.00 0.5 0.089 0.379 0.080 0.009 0.02 0.00
13 195 3.25 0.5 0.089 0.375 0.080 0.009 0.02 0.00
14 210 3.50 0.5 0.089 0.370 0.080 0.009 0.02 0.00
15 225 3.75 0.5 0.089 0.365 0.080 0.009 0.02 0.00
16 240 4.00 0.6 0.107 0.361 0.097 0.011 0.02 0.00
17 255 4.25 0.6 0.107 0.356 0.097 0.011 0.02 0.00
18 270 4.50 0.7 0.125 0.352 0.113 0.013 0.03 0.00
19 285 4.75 0.7 0.125 0.347 0.113 0.013 0.03 0.00
20 300 5.00 0.8 0.143 0.343 0.129 0.014 0.03 0.00
21 315 5.25 0.6 0.107 0.338 0.097 0.011 0.02 0.00
22 330 5.50 0.7 0.125 0.334 0.113 0.013 0.03 0.00
23 345 5.75 0.8 0.143 0.330 0.129 0.014 0.03 0.00
24 360 6.00 0.8 0.143 0.325 0.129 0.014 0.03 0.00
25 375 6.25 0.9 0.161 0.321 0.145 0.016 0.03 0.00
26 390 6.50 0.9 0.161 0.317 0.145 0.016 0.03 0.00
27 405 6.75 1.0 0.179 0.312 0.161 0.018 0.04 0.00
28 420 7.00 1.0 0.179 0.308 0.161 0.018 0.04 0.00
29 435 7.25 1.0 0.179 0.304 0.161 0.018 0.04 0.00
30 450 7.50 1.1 0.197 0.300 0.177 0.020 0.04 0.00
31 465 7.75 1.2 0.215 0.296 0.193 0.021 0.04 0.00
32 480 8.00 1.3 0.232 0.292 0.209 0.023 0.05 0.00
33 495 8.25 1.5 0.268 0.288 0.241 0.027 0.05 6.29
34 510 8.50 1.5 0.268 0.284 0.241 0.027 0.05 6.29
35 525 8.75 1.6 0.286 0.280 0.257 0.007 0.01 0.00
36 540 9.00 1.7 0.304 0.276 0.274 0.028 0.06 9.01
37 555 9.25 1.9 0.340 0.272 0.306 0.068 0.14 80.76
38 570 9.50 2.0 0.358 0.268 0.322 0.090 0.18 120.10
39 585 9.75 2.1 0.375 0.264 0.338 0.111 0.22 159.37
40 600 10.00 2.2 0.393 0.260 0.354 0.133 0.27 198.58
41 615 10.25 1.5 0.268 0.256 0.241 0.012 0.02 0.00
42 630 10.50 1.5 0.268 0.253 0.241 0.015 0.03 0.00
43 645 10.75 2.0 0.358 0.249 0.322 0.109 0.22 154.08
44 660 11.00 2.0 0.358 0.245 0.322 0.112 0.23 160.67
45 675 11.25 1.9 0.340 0.242 0.306 0.098 0.20 134.85
46 690 11.50 1.9 0.340 0.238 0.306 0.101 0.20 141.31
47 705 11.75 1.7 0.304 0.235 0.274 0.069 0.14 83.00
48 720 12.00 1.8 0.322 0.231 0.290 0.091 0.18 121.66
49 735 12.25 2.5 0.447 0.228 0.402 0.219 0.44 354.32
50 750 12.50 2.6 0.465 0.224 0.418 0.240 0.48 392.84
51 765 12.75 2.8 0.501 0.221 0.451 0.280 0.56 463.63
52 780 13.00 2.9 0.519 0.218 0.467 0.301 0.60 502.00
53 795 13.25 3.4 0.608 0.214 0.547 0.394 0.79 669.68
54 810 13.50 3.4 0.608 0.211 0.547 0.397 0.80 675.55
55 825 13.75 2.3 0.411 0.208 0.370 0.203 0.41 325.56
56 840 14.00 2.3 0.411 0.205 0.370 0.206 0.42 331.29
57 855 14.25 2.7 0.483 0.202 0.434 0.281 0.57 466.31
58 870 14.50 2.6 0.465 0.199 0.418 0.266 0.54 439.54
59 885 14.75 2.6 0.465 0.196 0.418 0.269 0.54 445.03
60 900 15.00 2.5 0.447 0.193 0.402 0.254 0.51 418.10
61 915 15.25 2.4 0.429 0.190 0.386 0.240 0.48 391.08
62 930 15.50 2.3 0.411 0.187 0.370 0.225 0.45 363.98
63 945 15.75 1.9 0.340 0.184 0.306 0.156 0.31 239.77
64 960 16.00 1.9 0.340 0.181 0.306 0.159 0.32 244.85
65 975 16.25 0.4 0.072 0.178 0.064 0.007 0.01 0.00
66 990 16.50 0.4 0.072 0.176 0.064 0.007 0.01 0.00
67 1005 16.75 0.3 0.054 0.173 0.048 0.005 0.01 0.00
Time Loss Rate
in/hr

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 7 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
68 1020 17.00 0.3 0.054 0.170 0.048 0.005 0.01 0.00
69 1035 17.25 0.5 0.089 0.168 0.080 0.009 0.02 0.00
70 1050 17.50 0.5 0.089 0.165 0.080 0.009 0.02 0.00
71 1065 17.75 0.5 0.089 0.163 0.080 0.009 0.02 0.00
72 1080 18.00 0.4 0.072 0.160 0.064 0.007 0.01 0.00
73 1095 18.25 0.4 0.072 0.158 0.064 0.007 0.01 0.00
74 1110 18.50 0.4 0.072 0.156 0.064 0.007 0.01 0.00
75 1125 18.75 0.3 0.054 0.153 0.048 0.005 0.01 0.00
76 1140 19.00 0.2 0.036 0.151 0.032 0.004 0.01 0.00
77 1155 19.25 0.3 0.054 0.149 0.048 0.005 0.01 0.00
78 1170 19.50 0.4 0.072 0.147 0.064 0.007 0.01 0.00
79 1185 19.75 0.3 0.054 0.145 0.048 0.005 0.01 0.00
80 1200 20.00 0.2 0.036 0.143 0.032 0.004 0.01 0.00
81 1215 20.25 0.3 0.054 0.141 0.048 0.005 0.01 0.00
82 1230 20.50 0.3 0.054 0.139 0.048 0.005 0.01 0.00
83 1245 20.75 0.3 0.054 0.138 0.048 0.005 0.01 0.00
84 1260 21.00 0.2 0.036 0.136 0.032 0.004 0.01 0.00
85 1275 21.25 0.3 0.054 0.134 0.048 0.005 0.01 0.00
86 1290 21.50 0.2 0.036 0.133 0.032 0.004 0.01 0.00
87 1305 21.75 0.3 0.054 0.131 0.048 0.005 0.01 0.00
88 1320 22.00 0.2 0.036 0.130 0.032 0.004 0.01 0.00
89 1335 22.25 0.3 0.054 0.129 0.048 0.005 0.01 0.00
90 1350 22.50 0.2 0.036 0.127 0.032 0.004 0.01 0.00
91 1365 22.75 0.2 0.036 0.126 0.032 0.004 0.01 0.00
92 1380 23.00 0.2 0.036 0.125 0.032 0.004 0.01 0.00
93 1395 23.25 0.2 0.036 0.124 0.032 0.004 0.01 0.00
94 1410 23.50 0.2 0.036 0.124 0.032 0.004 0.01 0.00
95 1425 23.75 0.2 0.036 0.123 0.032 0.004 0.01 0.00
96 1440 24.00 0.2 0.036 0.123 0.032 0.004 0.01 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.43
FLOOD VOLUME (acft) 0.24
FLOOD VOLUME (cuft) 10444.84
REQUIRED STORAGE (acft) 0.19
REQUIRED STORAGE (cuft) 8099.53
PEAK FLOW (cfs) 0.80
Plate E-2.2

Page 8 of 14 ends

Item 33.

PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB # 0
1 BASIN CHARACTERISTICS

CONTOUR DEPTH AREA VOLUME

INCR TOTAL INCR TOTAL INCR TOTAL
(ft) (ft) (sf) (sf) (cuft) (cuft) (acre-ft)
465 0 0 3025 0 0 0.00
466 1 1 675 3700 3363 3363 0.08
467 1 2 730 4430 4065 7428 0.17
468 1 3 785 5215 4823 12250 0.28
468.5 0.5 3.5 415 5630 2711 14961 0.34

PERCOLATION CALCULATIONS
PERCOLATION RATE 0.67 in/hr 0.05 cfs

MAXWELL IV DRYWELLS
NUMBER USED 0
RATE/DRYWELL 0 cfs
TOTAL DISSIPATED 0 cfs
TOTAL PERCOLATION RATE 0.05 cfs
Basin Characteristics

Page 9 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 3 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.17 52 52 14 37 465.01 37 0.00
2 10 0.17 52 89 14 75 465.02 75 0.00
3 15 0.07 21 96 14 82 465.02 82 0.00
4 20 0.27 82 164 14 150 465.04 150 0.00
5 25 0.27 82 232 14 218 465.06 218 0.01
6 30 0.43 128 346 14 332 465.10 332 0.01
7 35 0.27 82 414 14 400 465.12 400 0.01
8 40 0.43 128 529 14 514 465.15 514 0.01
9 45 0.43 128 643 14 629 465.19 629 0.01
10 50 0.27 82 711 14 697 465.21 697 0.02
11 55 0.33 98 794 14 780 465.23 780 0.02
12 60 0.43 128 908 14 894 465.27 894 0.02
13 65 0.63 190 1,084 14 1,070 465.32 1,070 0.02
14 70 0.63 190 1,260 14 1,245 465.37 1,245 0.03
15 75 0.63 190 1,435 14 1,421 465.42 1,421 0.03
16 80 0.53 159 1,580 14 1,566 465.47 1,566 0.04
17 85 0.84 251 1,817 14 1,803 465.54 1,803 0.04
18 90 0.89 266 2,069 14 2,055 465.61 2,055 0.05
19 95 0.73 220 2,275 14 2,261 465.67 2,261 0.05
20 100 0.89 266 2,527 14 2,513 465.75 2,513 0.06
21 105 1.19 358 2,872 14 2,858 465.85 2,858 0.07
22 110 1.09 328 3,185 14 3,171 465.94 3,171 0.07
23 115 0.99 297 3,468 14 3,454 466.02 3,454 0.08
24 120 1.04 312 3,766 14 3,752 466.10 3,752 0.09
25 125 1.09 328 4,080 14 4,066 466.17 4,066 0.09
26 130 1.65 496 4,562 14 4,548 466.29 4,548 0.10
27 135 2.06 619 5,167 14 5,153 466.44 5,153 0.12
28 140 1.30 389 5,542 14 5,528 466.53 5,528 0.13
29 145 2.98 895 6,424 14 6,409 466.75 6,409 0.15
30 150 3.24 972 7,381 14 7,367 466.99 7,367 0.17
31 155 3.70 1,110 8,477 14 8,463 467.21 8,463 0.19
32 160 2.52 757 9,220 14 9,206 467.37 9,206 0.21
33 165 0.53 159 9,365 14 9,351 467.40 9,351 0.21
34 170 0.43 128 9,479 14 9,465 467.42 9,465 0.22
35 175 0.43 128 9,594 14 9,580 467.45 9,580 0.22
36 180 0.03 9 9,589 14 9,575 467.45 9,575 0.22

BALANCE IN
BASIN
TIME
Basin Depth Analysis

Page 10 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.03 10 10 14 - 465.00 - 0.00
2 10 0.04 12 12 14 - 465.00 - 0.00
3 15 0.04 12 12 14 - 465.00 - 0.00
4 20 0.04 12 12 14 - 465.00 - 0.00
5 25 0.04 12 12 14 - 465.00 - 0.00
6 30 0.05 14 14 14 0 465.00 0.00 0
7 35 0.05 14 14 14 0 465.00 0.00 0
8 40 0.05 14 14 14 0 465.00 0.00 0
9 45 0.05 14 14 14 0 465.00 0.00 0
10 50 0.05 14 14 14 0 465.00 0.00 0
11 55 0.05 14 14 14 0 465.00 0.00 0
12 60 0.04 13 13 14 - 465.00 - 0.00
13 65 0.04 13 13 14 - 465.00 - 0.00
14 70 0.04 13 13 14 - 465.00 - 0.00
15 75 0.04 13 13 14 - 465.00 - 0.00
16 80 0.04 13 13 14 - 465.00 - 0.00
17 85 0.04 13 13 14 - 465.00 - 0.00
18 90 0.04 13 13 14 - 465.00 - 0.00
19 95 0.04 13 13 14 - 465.00 - 0.00
20 100 0.04 13 13 14 - 465.00 - 0.00
21 105 0.04 13 13 14 - 465.00 - 0.00
22 110 0.04 13 13 14 - 465.00 - 0.00
23 115 0.04 13 13 14 - 465.00 - 0.00
24 120 0.11 33 33 14 19 465.01 19 0.00
25 125 0.04 13 32 14 18 465.01 18 0.00
26 130 0.11 33 51 14 37 465.01 37 0.00
27 135 0.11 33 70 14 56 465.02 56 0.00
28 140 0.11 33 89 14 75 465.02 75 0.00
29 145 0.11 33 108 14 94 465.03 94 0.00
30 150 0.11 33 128 14 113 465.03 113 0.00
31 155 0.11 33 147 14 133 465.04 133 0.00
32 160 0.11 33 166 14 152 465.05 152 0.00
33 165 0.18 53 205 14 191 465.06 191 0.00
34 170 0.18 53 244 14 230 465.07 230 0.01
35 175 0.18 53 283 14 269 465.08 269 0.01
36 180 0.18 53 322 14 308 465.09 308 0.01
37 185 0.18 53 362 14 348 465.10 348 0.01
38 190 0.24 73 421 14 407 465.12 407 0.01
39 195 0.24 73 480 14 466 465.14 466 0.01
40 200 0.24 73 540 14 526 465.16 526 0.01
41 205 0.31 94 619 14 605 465.18 605 0.01
42 210 0.38 114 719 14 705 465.21 705 0.02
43 215 0.45 134 838 14 824 465.25 824 0.02
44 220 0.45 134 958 14 944 465.28 944 0.02
45 225 0.51 154 1,098 14 1,084 465.32 1,084 0.02
46 230 0.51 154 1,237 14 1,223 465.36 1,223 0.03
47 235 0.58 174 1,397 14 1,383 465.41 1,383 0.03
48 240 0.58 174 1,557 14 1,543 465.46 1,543 0.04
49 245 0.65 194 1,737 14 1,723 465.51 1,723 0.04
50 250 0.71 214 1,937 14 1,923 465.57 1,923 0.04
51 255 0.78 234 2,158 14 2,144 465.64 2,144 0.05
52 260 0.85 254 2,398 14 2,384 465.71 2,384 0.05
53 265 0.92 275 2,658 14 2,644 465.79 2,644 0.06
54 270 0.92 275 2,919 14 2,905 465.86 2,905 0.07
55 275 0.98 295 3,200 14 3,185 465.95 3,185 0.07

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 11 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
56 280 1.05 315 3,500 14 3,486 466.03 3,486 0.08
57 285 1.12 335 3,821 14 3,807 466.11 3,807 0.09
58 290 1.12 335 4,142 14 4,128 466.19 4,128 0.09
59 295 1.18 355 4,483 14 4,469 466.27 4,469 0.10
60 300 1.25 375 4,844 14 4,830 466.36 4,830 0.11
61 305 1.59 476 5,306 14 5,291 466.47 5,291 0.12
62 310 1.92 576 5,868 14 5,854 466.61 5,854 0.13
63 315 2.12 637 6,490 14 6,476 466.77 6,476 0.15
64 320 2.32 697 7,173 14 7,159 466.93 7,159 0.16
65 325 2.66 798 7,957 14 7,943 467.11 7,943 0.18
66 330 3.26 979 8,921 14 8,907 467.31 8,907 0.20
67 335 0.78 234 9,142 14 9,127 467.35 9,127 0.21
68 340 0.11 33 9,161 14 9,147 467.36 9,147 0.21
69 345 0.04 12 9,159 14 9,145 467.36 9,145 0.21
70 350 0.03 10 9,155 14 9,140 467.36 9,140 0.21
71 355 0.02 6 9,147 14 9,132 467.35 9,132 0.21
72 360 0.01 4 9,136 14 9,122 467.35 9,122 0.21
Basin Depth Analysis

Page 12 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 15 0.01 6 6 42 - 465.00 - 0.00
2 30 0.01 10 10 42 - 465.00 - 0.00
3 45 0.01 10 10 42 - 465.00 - 0.00
4 60 0.01 13 13 42 - 465.00 - 0.00
5 75 0.01 10 10 42 - 465.00 - 0.00
6 90 0.01 10 10 42 - 465.00 - 0.00
7 105 0.01 10 10 42 - 465.00 - 0.00
8 120 0.01 13 13 42 - 465.00 - 0.00
9 135 0.01 13 13 42 - 465.00 - 0.00
10 150 0.01 13 13 42 - 465.00 - 0.00
11 165 0.02 16 16 42 - 465.00 - 0.00
12 180 0.02 16 16 42 - 465.00 - 0.00
13 195 0.02 16 16 42 - 465.00 - 0.00
14 210 0.02 16 16 42 - 465.00 - 0.00
15 225 0.02 16 16 42 - 465.00 - 0.00
16 240 0.02 19 19 42 - 465.00 - 0.00
17 255 0.02 19 19 42 - 465.00 - 0.00
18 270 0.03 23 23 42 - 465.00 - 0.00
19 285 0.03 23 23 42 - 465.00 - 0.00
20 300 0.03 26 26 42 - 465.00 - 0.00
21 315 0.02 19 19 42 - 465.00 - 0.00
22 330 0.03 23 23 42 - 465.00 - 0.00
23 345 0.03 26 26 42 - 465.00 - 0.00
24 360 0.03 26 26 42 - 465.00 - 0.00
25 375 0.03 29 29 42 - 465.00 - 0.00
26 390 0.03 29 29 42 - 465.00 - 0.00
27 405 0.04 32 32 42 - 465.00 - 0.00
28 420 0.04 32 32 42 - 465.00 - 0.00
29 435 0.04 32 32 42 - 465.00 - 0.00
30 450 0.04 36 36 42 - 465.00 - 0.00
31 465 0.04 39 39 42 - 465.00 - 0.00
32 480 0.05 42 42 42 - 465.00 - 0.00
33 495 0.05 49 49 42 6 465.00 6 0.00
34 510 0.05 49 55 42 13 465.00 13 0.00
35 525 0.01 12 24 42 - 465.00 - 0.00
36 540 0.06 51 51 42 9 465.00 9 0.00
37 555 0.14 123 132 42 90 465.03 90 0.00
38 570 0.18 162 252 42 210 465.06 210 0.00
39 585 0.22 202 411 42 369 465.11 369 0.01
40 600 0.27 241 610 42 568 465.17 568 0.01
41 615 0.02 21 589 42 547 465.16 547 0.01
42 630 0.03 28 575 42 532 465.16 532 0.01
43 645 0.22 196 729 42 687 465.20 687 0.02
44 660 0.23 203 889 42 847 465.25 847 0.02
45 675 0.20 177 1,024 42 982 465.29 982 0.02
46 690 0.20 184 1,166 42 1,123 465.33 1,123 0.03
47 705 0.14 125 1,249 42 1,206 465.36 1,206 0.03
48 720 0.18 164 1,370 42 1,328 465.39 1,328 0.03
49 735 0.44 397 1,725 42 1,682 465.50 1,682 0.04
50 750 0.48 435 2,117 42 2,075 465.62 2,075 0.05
51 765 0.56 506 2,581 42 2,539 465.76 2,539 0.06
52 780 0.60 544 3,083 42 3,041 465.90 3,041 0.07
53 795 0.79 712 3,753 42 3,711 466.09 3,711 0.09
54 810 0.80 718 4,428 42 4,386 466.25 4,386 0.10
55 825 0.41 368 4,754 42 4,712 466.33 4,712 0.11
56 840 0.42 374 5,085 42 5,043 466.41 5,043 0.12
57 855 0.57 509 5,551 42 5,509 466.53 5,509 0.13
58 870 0.54 482 5,991 42 5,949 466.64 5,949 0.14

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 13 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
59 885 0.54 487 6,436 42 6,394 466.75 6,394 0.15
60 900 0.51 460 6,854 42 6,812 466.85 6,812 0.16
61 915 0.48 433 7,245 42 7,203 466.94 7,203 0.17
62 930 0.45 406 7,609 42 7,567 467.03 7,567 0.17
63 945 0.31 282 7,849 42 7,807 467.08 7,807 0.18
64 960 0.32 287 8,094 42 8,052 467.13 8,052 0.18
65 975 0.01 13 8,065 42 8,022 467.12 8,022 0.18
66 990 0.01 13 8,035 42 7,993 467.12 7,993 0.18
67 1005 0.01 10 8,003 42 7,961 467.11 7,961 0.18
68 1020 0.01 10 7,970 42 7,928 467.10 7,928 0.18
69 1035 0.02 16 7,944 42 7,902 467.10 7,902 0.18
70 1050 0.02 16 7,918 42 7,876 467.09 7,876 0.18
71 1065 0.02 16 7,892 42 7,850 467.09 7,850 0.18
72 1080 0.01 13 7,863 42 7,821 467.08 7,821 0.18
73 1095 0.01 13 7,833 42 7,791 467.08 7,791 0.18
74 1110 0.01 13 7,804 42 7,762 467.07 7,762 0.18
75 1125 0.01 10 7,772 42 7,729 467.06 7,729 0.18
76 1140 0.01 7,736 6 42 7,694 467.06 7,694 0.18
77 1155 0.01 10 7,703 42 7,661 467.05 7,661 0.18
78 1170 0.01 13 7,674 42 7,632 467.04 7,632 0.18
79 1185 0.01 10 7,642 42 7,599 467.04 7,599 0.17
80 1200 0.01 6 7,606 42 7,564 467.03 7,564 0.17
81 1215 0.01 10 7,573 42 7,531 467.02 7,531 0.17
82 1230 0.01 10 7,541 42 7,499 467.01 7,499 0.17
83 1245 0.01 10 7,508 42 7,466 467.01 7,466 0.17
84 1260 0.01 6 7,473 42 7,430 467.00 7,430 0.17
85 1275 0.01 10 7,440 42 7,398 466.99 7,398 0.17
86 1290 0.01 6 7,404 42 7,362 466.98 7,362 0.17
87 1305 0.01 10 7,372 42 7,330 466.98 7,330 0.17
88 1320 0.01 6 7,336 42 7,294 466.97 7,294 0.17
89 1335 0.01 10 7,303 42 7,261 466.96 7,261 0.17
90 1350 0.01 6 7,268 42 7,225 466.95 7,225 0.17
91 1365 0.01 6 7,232 42 7,190 466.94 7,190 0.17
92 1380 0.01 6 7,196 42 7,154 466.93 7,154 0.16
93 1395 0.01 6 7,160 42 7,118 466.92 7,118 0.16
94 1410 0.01 6 7,125 42 7,082 466.92 7,082 0.16
95 1425 0.01 6 7,089 42 7,047 466.91 7,047 0.16
96 1440 0.01 6 7,053 42 7,011 466.90 7,011 0.16
Basin Depth Analysis

Page 14 of 14 ends

Item 33.
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
37 38
39 40
41 42
43 44
45 46
47 48
49 50
51 52
53 54
55 56
AB C D

RCFCD SYNTHETIC UNIT HYDROGRAPH

DATA INPUT SHEET
WORKSHEET PREPARED BY: JAMES R. BAZUA, P.E.

PROJECT NAME CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB #
CONCENTRATION POINT DESIGNATION 1
AREA DESIGNATION SUBAREA 2

TRIBUTARY AREAS ACRES

COMMERCIAL
PAVING/HARDSCAPE 2.51
SF - 1 ACRE
SF - 1/2 ACRE
SF - 1/4 ACRE
MF - CONDOMINIUMS 7.46

MF - APARTMENTS

MOBILE HOME PARK
LANDSCAPING 0.6

RETENTION BASIN

GOLF COURSE

MOUNTAINOUS
LOW LOSS RATE (PERCENT) 90%
LENGTH OF WATERCOURSE (L) 724
LENGTH TO POINT OPPOSITE CENTROID (Lca) 100
ELEVATION OF HEADWATER 472
ELEVATION OF CONCENTRATION POINT 468.5
AVERAGE MANNINGS 'N' VALUE 0.02
STORM FREQUENCY (YEAR) 100

POINT RAIN
3-HOUR 2.12
6-HOUR 2.78
24-HOUR 4.47
BASIN CHARACTERISTICS: ELEVATION AREA
465 15600
466 17120
467 18710
468 20350
468.5 21200
PERCOLATION RATE (in/hr) 0.67

DRYWELL DATA

NUMBER USED
PERCOLATION RATE (cfs)

Page 1241 ends

Item 33.

POINT AREA AVERAGE POINT AREA AVERAGE POINT AREA AVERAGE

RAIN POINT RAIN POINT RAIN POINT

INCHES RAIN INCHES RAIN INCHES RAIN
(Plate E-5.2) INCHES (Plate E-5.4) INCHES (Plate E-5.6) INCHES

2.12 10.570 1.00 2.12 2.78 10.570 1.00 2.78 4.47 10.570 1.00 4.47

0.00 0.00 0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00
SUM [5] 10.57 SUM [7] 2.12 SUM [9] 10.57 SUM [11] 2.78 SUM [13] 10.57 SUM [15] 4.47 [16] AREA ADJ FACTOR 1.000 1.000 1.000
[17] ADJ AVG POINT RAIN 2.12 2.78 4.47
DURATION 3-HOUR 6-HOUR 24-HOUR
EFFECTIVE RAIN (in) 1.54 1.64 1.79
FLOOD VOLUME (cu-ft) 59,174 63,009 68,653
(acre-ft) 1.36 1.45 1.58
REQUIRED STORAGE (cu-ft) 56,096 57,661 56,204
(acre-ft) 1.29 1.32 1.29
PEAK FLOW (cfs) 20.00 17.69 4.66
MAXIMUM WSEL (ft) 468.11 468.19 468.12
24-HOURS
[15] LAG TIME-HOURS
[16] LAG TIME-MINUTES

0.24 STORM EVENT SUMMARY
[17] 100% OF LAG-MINUTES
[18] 200% OF LAG-MINUTES
[24] TOTAL PERCOLATION RATE (cfs)
[19] UNIT TIME-MINUTES (100%-200% OF LAG)
3-HOURS 6-HOURS
[6] La-FEET
[7] La-MILES
[8] ELEVATION OF HEADWATER
[9] ELEVATION OF CONCENTRATION POINT
[2] AREA DESIGNATION
[3] AREA - ACRES
[4] L-FEET
[5] L-MILES
5 0.03

1.6 1.6

3.2 25.5

5.05 0.02

PHYSICAL DATA

RAINFALL DATA
[1] CONCENTRATION POINT 1
SUBAREA 2

10.570
724

0.019
472
468.5

0.137
100.00

0.001
[12] S^0.5
[13] L*LCA/S^0.5
[14] AVERAGE MANNINGS 'N'
[10] H-FEET 3.5
[11] S-FEET/MILE
Plate E-2.1

Page 2 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT CALHOUN AT AVENUE 49 - 100 YEAR EVENT CONCENTRATION POINT: 1BY MES R. BAZUA, P.E. DATE 1/17/2025

ADJUSTED LOSS RATE

SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AVERAGE

GROUP NUMBER AREA PERCENT INFILTRATION ADJUSTED

INFILTRATION OF AREA RATE INFILTRATION

RATE IMPERVIOUS RATE
(in/hr) (in/hr) (in/hr)
[Plate C-1] [Plate E-6.1] [Plate E-6.2] [Plate E-6.3]
B 56 0.52 90% 0.10 0.00 0.000 0.0000
B 56 0.52 100% 0.05 2.51 0.237 0.0123
B 56 0.52 20% 0.43 0.00 0.000 0.0000B 56 0.52 40% 0.33 0.00 0.000 0.0000B 56 0.52 50% 0.29 0.00 0.000 0.0000B 56 0.52 65% 0.22 7.46 0.706 0.1523B 56 0.52 80% 0.15 0.00 0.000 0.0000B 56 0.52 75% 0.17 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.60 0.057 0.0295B 56 0.52 0% 0.52 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.00 0.000 0.0000 D 93 0.95 90% 0.18 0.00 0.000 0.0000

0.00 0.000 0.0000

0.00 0.000 0.0000
SUM 10.57 SUM 0.1942
VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY)Fm= 0.097085525C= 0.00180Ft=C(24-(T/60))^1.55 = 0.00180 0.10 in/hr LOW LOSS RATE (80-90 PERCENT) = 90%Where:T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,T=1 1/2 unit time for the second period, etc.

LANDSCAPING

RETENTION BASINS

GOLF COURSE

MOUNTAINOUS
SF - 1 ACRE
SF - 1/2 ACRESF - 1/4 ACRE
MF - COND0MINIUMS

MF - APARTMENTS

MOBILE HOME PARKS
(24-(T/60))^1.55 +

LAND USE

COMMERCIAL

PAVING/HARDSCAPE
Plate E-2.1

Page 3 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 3 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: MES R. BAZUA, DATE 1/17/2025
DRAINAGE AREA-ACRES 10.57
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 1.62
UNIT TIME-PERCENT OF LAG 308.6
TOTAL ADJUSTED STORM RAIN-INCHES 2.12
CONSTANT LOSS RATE-in/hr 0.19
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.24 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 1.3 0.331 0.19 0.30 0.14 1.44 360.41
2 10 0.17 1.3 0.331 0.19 0.30 0.14 1.44 360.41
3 15 0.25 1.1 0.280 0.19 0.25 0.09 0.91 199.07
4 20 0.33 1.5 0.382 0.19 0.34 0.19 1.98 521.75
5 25 0.42 1.5 0.382 0.19 0.34 0.19 1.98 521.75
6 30 0.50 1.8 0.458 0.19 0.41 0.26 2.79 763.76
7 35 0.58 1.5 0.382 0.19 0.34 0.19 1.98 521.75
8 40 0.67 1.8 0.458 0.19 0.41 0.26 2.79 763.76
9 45 0.75 1.8 0.458 0.19 0.41 0.26 2.79 763.76
10 50 0.83 1.5 0.382 0.19 0.34 0.19 1.98 521.75
11 55 0.92 1.6 0.407 0.19 0.37 0.21 2.25 602.42
12 60 1.00 1.8 0.458 0.19 0.41 0.26 2.79 763.76
13 65 1.08 2.2 0.560 0.19 0.50 0.37 3.86 1086.45
14 70 1.17 2.2 0.560 0.19 0.50 0.37 3.86 1086.45
15 75 1.25 2.2 0.560 0.19 0.50 0.37 3.86 1086.45
16 80 1.33 2.0 0.509 0.19 0.46 0.31 3.33 925.11
17 85 1.42 2.6 0.661 0.19 0.60 0.47 4.94 1409.13
18 90 1.50 2.7 0.687 0.19 0.62 0.49 5.21 1489.80
19 95 1.58 2.4 0.611 0.19 0.55 0.42 4.40 1247.79
20 100 1.67 2.7 0.687 0.19 0.62 0.49 5.21 1489.80
21 105 1.75 3.3 0.840 0.19 0.76 0.65 6.82 1973.82
22 110 1.83 3.1 0.789 0.19 0.71 0.59 6.28 1812.48
23 115 1.92 2.9 0.738 0.19 0.66 0.54 5.75 1651.14
24 120 2.00 3.0 0.763 0.19 0.69 0.57 6.01 1731.81
25 125 2.08 3.1 0.789 0.19 0.71 0.59 6.28 1812.48
26 130 2.17 4.2 1.068 0.19 0.96 0.87 9.24 2699.85
27 135 2.25 5.0 1.272 0.19 1.14 1.08 11.39 3345.21
28 140 2.33 3.5 0.890 0.19 0.80 0.70 7.36 2135.16
29 145 2.42 6.8 1.730 0.19 1.56 1.54 16.23 4797.28
30 150 2.50 7.3 1.857 0.19 1.67 1.66 17.58 5200.63
31 155 2.58 8.2 2.086 0.19 1.88 1.89 20.00 5926.66
32 160 2.67 5.9 1.501 0.19 1.35 1.31 13.81 4071.24
33 165 2.75 2.0 0.509 0.19 0.46 0.31 3.33 925.11
34 170 2.83 1.8 0.458 0.19 0.41 0.26 2.79 763.76
35 175 2.92 1.8 0.458 0.19 0.41 0.26 2.79 763.76
36 180 3.00 0.6 0.153 0.19 0.14 0.02 0.16 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.54
FLOOD VOLUME (acft) 1.36
FLOOD VOLUME (cuft) 59173.82
REQUIRED STORAGE (acft) 1.29
REQUIRED STORAGE (cuft) 56095.73
PEAK FLOW RATE (cfs) 20.00
Loss Rate
in/hr
Time

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 4 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 6 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 10.57
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 1.62
UNIT TIME-PERCENT OF LAG 308.6
TOTAL ADJUSTED STORM RAIN-INCHES 2.78
CONSTANT LOSS RATE-in/hr 0.194
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.24 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 0.5 0.167 0.19 0.15 0.02 0.18 0.00
2 10 0.17 0.6 0.200 0.19 0.18 0.01 0.06 0.00
3 15 0.25 0.6 0.200 0.19 0.18 0.01 0.06 0.00
4 20 0.33 0.6 0.200 0.19 0.18 0.01 0.06 0.00
5 25 0.42 0.6 0.200 0.19 0.18 0.01 0.06 0.00
6 30 0.50 0.7 0.234 0.19 0.21 0.04 0.42 52.19
7 35 0.58 0.7 0.234 0.19 0.21 0.04 0.42 52.19
8 40 0.67 0.7 0.234 0.19 0.21 0.04 0.42 52.19
9 45 0.75 0.7 0.234 0.19 0.21 0.04 0.42 52.19
10 50 0.83 0.7 0.234 0.19 0.21 0.04 0.42 52.19
11 55 0.92 0.7 0.234 0.19 0.21 0.04 0.42 52.19
12 60 1.00 0.8 0.267 0.19 0.24 0.07 0.77 157.98
13 65 1.08 0.8 0.267 0.19 0.24 0.07 0.77 157.98
14 70 1.17 0.8 0.267 0.19 0.24 0.07 0.77 157.98
15 75 1.25 0.8 0.267 0.19 0.24 0.07 0.77 157.98
16 80 1.33 0.8 0.267 0.19 0.24 0.07 0.77 157.98
17 85 1.42 0.8 0.267 0.19 0.24 0.07 0.77 157.98
18 90 1.50 0.8 0.267 0.19 0.24 0.07 0.77 157.98
19 95 1.58 0.8 0.267 0.19 0.24 0.07 0.77 157.98
20 100 1.67 0.8 0.267 0.19 0.24 0.07 0.77 157.98
21 105 1.75 0.8 0.267 0.19 0.24 0.07 0.77 157.98
22 110 1.83 0.8 0.267 0.19 0.24 0.07 0.77 157.98
23 115 1.92 0.8 0.267 0.19 0.24 0.07 0.77 157.98
24 120 2.00 0.9 0.300 0.19 0.27 0.11 1.12 263.76
25 125 2.08 0.8 0.267 0.19 0.24 0.07 0.77 157.98
26 130 2.17 0.9 0.300 0.19 0.27 0.11 1.12 263.76
27 135 2.25 0.9 0.300 0.19 0.27 0.11 1.12 263.76
28 140 2.33 0.9 0.300 0.19 0.27 0.11 1.12 263.76
29 145 2.42 0.9 0.300 0.19 0.27 0.11 1.12 263.76
30 150 2.50 0.9 0.300 0.19 0.27 0.11 1.12 263.76
31 155 2.58 0.9 0.300 0.19 0.27 0.11 1.12 263.76
32 160 2.67 0.9 0.300 0.19 0.27 0.11 1.12 263.76
33 165 2.75 1.0 0.334 0.19 0.30 0.14 1.47 369.55
34 170 2.83 1.0 0.334 0.19 0.30 0.14 1.47 369.55
35 175 2.92 1.0 0.334 0.19 0.30 0.14 1.47 369.55
36 180 3.00 1.0 0.334 0.19 0.30 0.14 1.47 369.55
37 185 3.08 1.0 0.334 0.19 0.30 0.14 1.47 369.55
38 190 3.17 1.1 0.367 0.19 0.33 0.17 1.83 475.33
39 195 3.25 1.1 0.367 0.19 0.33 0.17 1.83 475.33
40 200 3.33 1.1 0.367 0.19 0.33 0.17 1.83 475.33
41 205 3.42 1.2 0.400 0.19 0.36 0.21 2.18 581.11
42 210 3.50 1.3 0.434 0.19 0.39 0.24 2.53 686.90
43 215 3.58 1.4 0.467 0.19 0.42 0.27 2.88 792.68
44 220 3.67 1.4 0.467 0.19 0.42 0.27 2.88 792.68
45 225 3.75 1.5 0.500 0.19 0.45 0.31 3.24 898.47
46 230 3.83 1.5 0.500 0.19 0.45 0.31 3.24 898.47
47 235 3.92 1.6 0.534 0.19 0.48 0.34 3.59 1004.25
48 240 4.00 1.6 0.534 0.19 0.48 0.34 3.59 1004.25
49 245 4.08 1.7 0.567 0.19 0.51 0.37 3.94 1110.04
50 250 4.17 1.8 0.600 0.19 0.54 0.41 4.29 1215.82
51 255 4.25 1.9 0.634 0.19 0.57 0.44 4.65 1321.61
52 260 4.33 2.0 0.667 0.19 0.60 0.47 5.00 1427.39
53 265 4.42 2.1 0.701 0.19 0.63 0.51 5.35 1533.18
54 270 4.50 2.1 0.701 0.19 0.63 0.51 5.35 1533.18
55 275 4.58 2.2 0.734 0.19 0.66 0.54 5.71 1638.96
56 280 4.67 2.3 0.767 0.19 0.69 0.57 6.06 1744.75

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
Plate E-2.2

Page 5 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
57 285 4.75 2.4 0.801 0.19 0.72 0.61 6.41 1850.53
58 290 4.83 2.4 0.801 0.19 0.72 0.61 6.41 1850.53
59 295 4.92 2.5 0.834 0.19 0.75 0.64 6.76 1956.31
60 300 5.00 2.6 0.867 0.19 0.78 0.67 7.12 2062.10
61 305 5.08 3.1 1.034 0.19 0.93 0.84 8.88 2591.02
62 310 5.17 3.6 1.201 0.19 1.08 1.01 10.64 3119.94
63 315 5.25 3.9 1.301 0.19 1.17 1.11 11.70 3437.30
64 320 5.33 4.2 1.401 0.19 1.26 1.21 12.76 3754.65
65 325 5.42 4.7 1.568 0.19 1.41 1.37 14.52 4283.57
66 330 5.50 5.6 1.868 0.19 1.68 1.67 17.69 5235.64
67 335 5.58 1.9 0.634 0.19 0.57 0.44 4.65 1321.61
68 340 5.67 0.9 0.300 0.19 0.27 0.11 1.12 263.76
69 345 5.75 0.6 0.200 0.19 0.18 0.01 0.06 0.00
70 350 5.83 0.5 0.167 0.19 0.15 0.02 0.18 0.00
71 355 5.92 0.3 0.100 0.19 0.09 0.01 0.11 0.00
72 360 6.00 0.2 0.067 0.19 0.06 0.01 0.07 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.64
FLOOD VOLUME (acft) 1.45
FLOOD VOLUME (cuft) 63008.73
REQUIRED STORAGE (acft) 1.32
REQUIRED STORAGE (cuft) 57661.37
PEAK FLOW RATE (cfs) 17.69
Plate E-2.2

Page 6 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 24 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 10.570 CONSTANT LOSS RATE-in/hr n/a UNIT TIME-MINUTES 15 VARIABLE LOSS RATE (AVG) in/hr 0.1942 LAG TIME - MINUTES 1.62 MINIMUM LOSS RATE (for var. loss) - in/hr 0.097 UNIT TIME-PERCENT OF LAG 925.8 LOW LOSS RATE - DECIMAL 0.90 TOTAL ADJUSTED STORM RAIN-INCHES 4.47 C 0.00180
PERCOLATION RATE (cfs) 0.24
Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 15 0.25 0.2 0.036 0.343 0.032 0.004 0.04 0.00
2 30 0.50 0.3 0.054 0.339 0.048 0.005 0.06 0.00
3 45 0.75 0.3 0.054 0.335 0.048 0.005 0.06 0.00
4 60 1.00 0.4 0.072 0.331 0.064 0.007 0.08 0.00
5 75 1.25 0.3 0.054 0.327 0.048 0.005 0.06 0.00
6 90 1.50 0.3 0.054 0.323 0.048 0.005 0.06 0.00
7 105 1.75 0.3 0.054 0.319 0.048 0.005 0.06 0.00
8 120 2.00 0.4 0.072 0.316 0.064 0.007 0.08 0.00
9 135 2.25 0.4 0.072 0.312 0.064 0.007 0.08 0.00
10 150 2.50 0.4 0.072 0.308 0.064 0.007 0.08 0.00
11 165 2.75 0.5 0.089 0.304 0.080 0.009 0.09 0.00
12 180 3.00 0.5 0.089 0.300 0.080 0.009 0.09 0.00
13 195 3.25 0.5 0.089 0.297 0.080 0.009 0.09 0.00
14 210 3.50 0.5 0.089 0.293 0.080 0.009 0.09 0.00
15 225 3.75 0.5 0.089 0.289 0.080 0.009 0.09 0.00
16 240 4.00 0.6 0.107 0.286 0.097 0.011 0.11 0.00
17 255 4.25 0.6 0.107 0.282 0.097 0.011 0.11 0.00
18 270 4.50 0.7 0.125 0.278 0.113 0.013 0.13 0.00
19 285 4.75 0.7 0.125 0.275 0.113 0.013 0.13 0.00
20 300 5.00 0.8 0.143 0.271 0.129 0.014 0.15 0.00
21 315 5.25 0.6 0.107 0.268 0.097 0.011 0.11 0.00
22 330 5.50 0.7 0.125 0.264 0.113 0.013 0.13 0.00
23 345 5.75 0.8 0.143 0.261 0.129 0.014 0.15 0.00
24 360 6.00 0.8 0.143 0.257 0.129 0.014 0.15 0.00
25 375 6.25 0.9 0.161 0.254 0.145 0.016 0.17 0.00
26 390 6.50 0.9 0.161 0.251 0.145 0.016 0.17 0.00
27 405 6.75 1.0 0.179 0.247 0.161 0.018 0.19 0.00
28 420 7.00 1.0 0.179 0.244 0.161 0.018 0.19 0.00
29 435 7.25 1.0 0.179 0.241 0.161 0.018 0.19 0.00
30 450 7.50 1.1 0.197 0.237 0.177 0.020 0.21 0.00
31 465 7.75 1.2 0.215 0.234 0.193 0.021 0.23 0.00
32 480 8.00 1.3 0.232 0.231 0.209 0.002 0.02 0.00
33 495 8.25 1.5 0.268 0.228 0.241 0.041 0.43 167.88
34 510 8.50 1.5 0.268 0.224 0.241 0.044 0.46 198.07
35 525 8.75 1.6 0.286 0.221 0.257 0.065 0.68 398.09
36 540 9.00 1.7 0.304 0.218 0.274 0.086 0.91 597.84
37 555 9.25 1.9 0.340 0.215 0.306 0.125 1.32 967.41
38 570 9.50 2.0 0.358 0.212 0.322 0.146 1.54 1166.63
39 585 9.75 2.1 0.375 0.209 0.338 0.166 1.76 1365.57
40 600 10.00 2.2 0.393 0.206 0.354 0.187 1.98 1564.23
41 615 10.25 1.5 0.268 0.203 0.241 0.065 0.69 401.88
42 630 10.50 1.5 0.268 0.200 0.241 0.068 0.72 429.90
43 645 10.75 2.0 0.358 0.197 0.322 0.160 1.70 1308.09
44 660 11.00 2.0 0.358 0.194 0.322 0.163 1.73 1335.54
45 675 11.25 1.9 0.340 0.191 0.306 0.148 1.57 1192.62
46 690 11.50 1.9 0.340 0.189 0.306 0.151 1.60 1219.49
47 705 11.75 1.7 0.304 0.186 0.274 0.118 1.25 905.90
48 720 12.00 1.8 0.322 0.183 0.290 0.139 1.47 1102.28
49 735 12.25 2.5 0.447 0.180 0.402 0.267 2.82 2318.92
50 750 12.50 2.6 0.465 0.178 0.418 0.287 3.04 2514.71
51 765 12.75 2.8 0.501 0.175 0.451 0.326 3.44 2880.29
52 780 13.00 2.9 0.519 0.172 0.467 0.346 3.66 3075.47
53 795 13.25 3.4 0.608 0.170 0.547 0.438 4.63 3950.71
54 810 13.50 3.4 0.608 0.167 0.547 0.441 4.66 3975.18
55 825 13.75 2.3 0.411 0.165 0.370 0.247 2.61 2128.32
56 840 14.00 2.3 0.411 0.162 0.370 0.249 2.63 2152.16
57 855 14.25 2.7 0.483 0.160 0.434 0.323 3.42 2856.04
58 870 14.50 2.6 0.465 0.157 0.418 0.308 3.25 2709.14
59 885 14.75 2.6 0.465 0.155 0.418 0.310 3.28 2732.00
60 900 15.00 2.5 0.447 0.152 0.402 0.295 3.11 2584.44
61 915 15.25 2.4 0.429 0.150 0.386 0.279 2.95 2436.54
62 930 15.50 2.3 0.411 0.148 0.370 0.263 2.78 2288.29
63 945 15.75 1.9 0.340 0.146 0.306 0.194 2.05 1629.43
64 960 16.00 1.9 0.340 0.143 0.306 0.196 2.08 1650.58
65 975 16.25 0.4 0.072 0.141 0.064 0.007 0.08 0.00
66 990 16.50 0.4 0.072 0.139 0.064 0.007 0.08 0.00
67 1005 16.75 0.3 0.054 0.137 0.048 0.005 0.06 0.00
Time Loss Rate
in/hr

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 7 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
68 1020 17.00 0.3 0.054 0.135 0.048 0.005 0.06 0.00
69 1035 17.25 0.5 0.089 0.133 0.080 0.009 0.09 0.00
70 1050 17.50 0.5 0.089 0.131 0.080 0.009 0.09 0.00
71 1065 17.75 0.5 0.089 0.129 0.080 0.009 0.09 0.00
72 1080 18.00 0.4 0.072 0.127 0.064 0.007 0.08 0.00
73 1095 18.25 0.4 0.072 0.125 0.064 0.007 0.08 0.00
74 1110 18.50 0.4 0.072 0.123 0.064 0.007 0.08 0.00
75 1125 18.75 0.3 0.054 0.121 0.048 0.005 0.06 0.00
76 1140 19.00 0.2 0.036 0.120 0.032 0.004 0.04 0.00
77 1155 19.25 0.3 0.054 0.118 0.048 0.005 0.06 0.00
78 1170 19.50 0.4 0.072 0.116 0.064 0.007 0.08 0.00
79 1185 19.75 0.3 0.054 0.115 0.048 0.005 0.06 0.00
80 1200 20.00 0.2 0.036 0.113 0.032 0.004 0.04 0.00
81 1215 20.25 0.3 0.054 0.112 0.048 0.005 0.06 0.00
82 1230 20.50 0.3 0.054 0.110 0.048 0.005 0.06 0.00
83 1245 20.75 0.3 0.054 0.109 0.048 0.005 0.06 0.00
84 1260 21.00 0.2 0.036 0.108 0.032 0.004 0.04 0.00
85 1275 21.25 0.3 0.054 0.106 0.048 0.005 0.06 0.00
86 1290 21.50 0.2 0.036 0.105 0.032 0.004 0.04 0.00
87 1305 21.75 0.3 0.054 0.104 0.048 0.005 0.06 0.00
88 1320 22.00 0.2 0.036 0.103 0.032 0.004 0.04 0.00
89 1335 22.25 0.3 0.054 0.102 0.048 0.005 0.06 0.00
90 1350 22.50 0.2 0.036 0.101 0.032 0.004 0.04 0.00
91 1365 22.75 0.2 0.036 0.100 0.032 0.004 0.04 0.00
92 1380 23.00 0.2 0.036 0.099 0.032 0.004 0.04 0.00
93 1395 23.25 0.2 0.036 0.099 0.032 0.004 0.04 0.00
94 1410 23.50 0.2 0.036 0.098 0.032 0.004 0.04 0.00
95 1425 23.75 0.2 0.036 0.097 0.032 0.004 0.04 0.00
96 1440 24.00 0.2 0.036 0.097 0.032 0.004 0.04 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.79
FLOOD VOLUME (acft) 1.58
FLOOD VOLUME (cuft) 68652.95
REQUIRED STORAGE (acft) 1.29
REQUIRED STORAGE (cuft) 56203.65
PEAK FLOW (cfs) 4.66
Plate E-2.2

Page 8 of 14 ends

Item 33.

PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB # 0
1 BASIN CHARACTERISTICS

CONTOUR DEPTH AREA VOLUME

INCR TOTAL INCR TOTAL INCR TOTAL
(ft) (ft) (sf) (sf) (cuft) (cuft) (acre-ft)
465 0 0 15600 0 0 0.00
466 1 1 1520 17120 16360 16360 0.38
467 1 2 1590 18710 17915 34275 0.79
468 1 3 1640 20350 19530 53805 1.24
468.5 0.5 3.5 850 21200 10388 64193 1.47

PERCOLATION CALCULATIONS
PERCOLATION RATE 0.67 in/hr 0.24 cfs

MAXWELL IV DRYWELLS
NUMBER USED 0
RATE/DRYWELL 0 cfs
TOTAL DISSIPATED 0 cfs
TOTAL PERCOLATION RATE 0.24 cfs
Basin Characteristics

Page 9 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 3 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 1.44 433 433 73 360 465.02 360 0.01
2 10 1.44 433 793 73 721 465.04 721 0.02
3 15 0.91 272 992 73 920 465.06 920 0.02
4 20 1.98 594 1,514 73 1,442 465.09 1,442 0.03
5 25 1.98 594 2,036 73 1,963 465.12 1,963 0.05
6 30 2.79 836 2,800 73 2,727 465.17 2,727 0.06
7 35 1.98 594 3,322 73 3,249 465.20 3,249 0.07
8 40 2.79 836 4,085 73 4,013 465.25 4,013 0.09
9 45 2.79 836 4,849 73 4,776 465.29 4,776 0.11
10 50 1.98 594 5,371 73 5,298 465.32 5,298 0.12
11 55 2.25 675 5,973 73 5,901 465.36 5,901 0.14
12 60 2.79 836 6,737 73 6,664 465.41 6,664 0.15
13 65 3.86 1,159 7,823 73 7,751 465.47 7,751 0.18
14 70 3.86 1,159 8,910 73 8,837 465.54 8,837 0.20
15 75 3.86 1,159 9,996 73 9,924 465.61 9,924 0.23
16 80 3.33 998 10,921 73 10,849 465.66 10,849 0.25
17 85 4.94 1,482 12,331 73 12,258 465.75 12,258 0.28
18 90 5.21 1,562 13,820 73 13,748 465.84 13,748 0.32
19 95 4.40 1,320 15,068 73 14,996 465.92 14,996 0.34
20 100 5.21 1,562 16,558 73 16,485 466.01 16,485 0.38
21 105 6.82 2,046 18,532 73 18,459 466.12 18,459 0.42
22 110 6.28 1,885 20,344 73 20,272 466.22 20,272 0.47
23 115 5.75 1,724 21,995 73 21,923 466.31 21,923 0.50
24 120 6.01 1,804 23,727 73 23,655 466.41 23,655 0.54
25 125 6.28 1,885 25,540 73 25,467 466.51 25,467 0.58
26 130 9.24 2,772 28,239 73 28,167 466.66 28,167 0.65
27 135 11.39 3,418 31,585 73 31,512 466.85 31,512 0.72
28 140 7.36 2,208 33,720 73 33,647 466.96 33,647 0.77
29 145 16.23 4,870 38,517 73 38,445 467.21 38,445 0.88
30 150 17.58 5,273 43,718 73 43,645 467.48 43,645 1.00
31 155 20.00 5,999 49,644 73 49,572 467.78 49,572 1.14
32 160 13.81 4,144 53,716 73 53,643 467.99 53,643 1.23
33 165 3.33 998 54,641 73 54,568 468.04 54,568 1.25
34 170 2.79 836 55,405 73 55,332 468.07 55,332 1.27
35 175 2.79 836 56,168 73 56,096 468.11 56,096 1.29
36 180 0.16 48 56,144 73 56,072 468.11 56,072 1.29

BALANCE IN
BASIN
TIME
Basin Depth Analysis

Page 10 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.18 53 53 73 - 465.00 - 0.00
2 10 0.06 19 19 73 - 465.00 - 0.00
3 15 0.06 19 19 73 - 465.00 - 0.00
4 20 0.06 19 19 73 - 465.00 - 0.00
5 25 0.06 19 19 73 - 465.00 - 0.00
6 30 0.42 125 125 73 52 465.00 52 0.00
7 35 0.42 125 177 73 104 465.01 104 0.00
8 40 0.42 125 229 73 157 465.01 157 0.00
9 45 0.42 125 281 73 209 465.01 209 0.00
10 50 0.42 125 334 73 261 465.02 261 0.01
11 55 0.42 125 386 73 313 465.02 313 0.01
12 60 0.77 231 544 73 471 465.03 471 0.01
13 65 0.77 231 702 73 629 465.04 629 0.01
14 70 0.77 231 860 73 787 465.05 787 0.02
15 75 0.77 231 1,018 73 945 465.06 945 0.02
16 80 0.77 231 1,176 73 1,103 465.07 1,103 0.03
17 85 0.77 231 1,334 73 1,261 465.08 1,261 0.03
18 90 0.77 231 1,492 73 1,419 465.09 1,419 0.03
19 95 0.77 231 1,650 73 1,577 465.10 1,577 0.04
20 100 0.77 231 1,808 73 1,735 465.11 1,735 0.04
21 105 0.77 231 1,966 73 1,893 465.12 1,893 0.04
22 110 0.77 231 2,123 73 2,051 465.13 2,051 0.05
23 115 0.77 231 2,281 73 2,209 465.14 2,209 0.05
24 120 1.12 336 2,545 73 2,473 465.15 2,473 0.06
25 125 0.77 231 2,703 73 2,631 465.16 2,631 0.06
26 130 1.12 336 2,967 73 2,894 465.18 2,894 0.07
27 135 1.12 336 3,231 73 3,158 465.19 3,158 0.07
28 140 1.12 336 3,494 73 3,422 465.21 3,422 0.08
29 145 1.12 336 3,758 73 3,686 465.23 3,686 0.08
30 150 1.12 336 4,022 73 3,949 465.24 3,949 0.09
31 155 1.12 336 4,286 73 4,213 465.26 4,213 0.10
32 160 1.12 336 4,550 73 4,477 465.27 4,477 0.10
33 165 1.47 442 4,919 73 4,846 465.30 4,846 0.11
34 170 1.47 442 5,289 73 5,216 465.32 5,216 0.12
35 175 1.47 442 5,658 73 5,586 465.34 5,586 0.13
36 180 1.47 442 6,028 73 5,955 465.36 5,955 0.14
37 185 1.47 442 6,397 73 6,325 465.39 6,325 0.15
38 190 1.83 548 6,873 73 6,800 465.42 6,800 0.16
39 195 1.83 548 7,348 73 7,275 465.44 7,275 0.17
40 200 1.83 548 7,823 73 7,751 465.47 7,751 0.18
41 205 2.18 654 8,404 73 8,332 465.51 8,332 0.19
42 210 2.53 759 9,091 73 9,019 465.55 9,019 0.21
43 215 2.88 865 9,884 73 9,811 465.60 9,811 0.23
44 220 2.88 865 10,677 73 10,604 465.65 10,604 0.24
45 225 3.24 971 11,575 73 11,503 465.70 11,503 0.26
46 230 3.24 971 12,474 73 12,401 465.76 12,401 0.28
47 235 3.59 1,077 13,478 73 13,405 465.82 13,405 0.31
48 240 3.59 1,077 14,482 73 14,409 465.88 14,409 0.33
49 245 3.94 1,183 15,592 73 15,520 465.95 15,520 0.36
50 250 4.29 1,288 16,808 73 16,735 466.02 16,735 0.38
51 255 4.65 1,394 18,130 73 18,057 466.09 18,057 0.41
52 260 5.00 1,500 19,557 73 19,484 466.17 19,484 0.45
53 265 5.35 1,606 21,090 73 21,018 466.26 21,018 0.48
54 270 5.35 1,606 22,623 73 22,551 466.35 22,551 0.52
55 275 5.71 1,712 24,262 73 24,190 466.44 24,190 0.56

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 11 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
56 280 6.06 1,817 26,007 73 25,934 466.53 25,934 0.60
57 285 6.41 1,923 27,858 73 27,785 466.64 27,785 0.64
58 290 6.41 1,923 29,708 73 29,635 466.74 29,635 0.68
59 295 6.76 2,029 31,664 73 31,592 466.85 31,592 0.73
60 300 7.12 2,135 33,726 73 33,654 466.97 33,654 0.77
61 305 8.88 2,664 36,317 73 36,245 467.10 36,245 0.83
62 310 10.64 3,193 39,437 73 39,365 467.26 39,365 0.90
63 315 11.70 3,510 42,875 73 42,802 467.44 42,802 0.98
64 320 12.76 3,827 46,629 73 46,557 467.63 46,557 1.07
65 325 14.52 4,356 50,913 73 50,840 467.85 50,840 1.17
66 330 17.69 5,308 56,149 73 56,076 468.11 56,076 1.29
67 335 4.65 1,394 57,470 73 57,398 468.17 57,398 1.32
68 340 1.12 336 57,734 73 57,661 468.19 57,661 1.32
69 345 0.06 19 57,680 73 57,608 468.18 57,608 1.32
70 350 0.18 53 57,661 73 57,588 468.18 57,588 1.32
71 355 0.11 32 57,620 73 57,547 468.18 57,547 1.32
72 360 0.07 21 57,568 73 57,496 468.18 57,496 1.32
Basin Depth Analysis

Page 12 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 15 0.04 34 34 218 - 465.00 - 0.00
2 30 0.06 51 51 218 - 465.00 - 0.00
3 45 0.06 51 51 218 - 465.00 - 0.00
4 60 0.08 68 68 218 - 465.00 - 0.00
5 75 0.06 51 51 218 - 465.00 - 0.00
6 90 0.06 51 51 218 - 465.00 - 0.00
7 105 0.06 51 51 218 - 465.00 - 0.00
8 120 0.08 68 68 218 - 465.00 - 0.00
9 135 0.08 68 68 218 - 465.00 - 0.00
10 150 0.08 68 68 218 - 465.00 - 0.00
11 165 0.09 85 85 218 - 465.00 - 0.00
12 180 0.09 85 85 218 - 465.00 - 0.00
13 195 0.09 85 85 218 - 465.00 - 0.00
14 210 0.09 85 85 218 - 465.00 - 0.00
15 225 0.09 85 85 218 - 465.00 - 0.00
16 240 0.11 102 102 218 - 465.00 - 0.00
17 255 0.11 102 102 218 - 465.00 - 0.00
18 270 0.13 119 119 218 - 465.00 - 0.00
19 285 0.13 119 119 218 - 465.00 - 0.00
20 300 0.15 136 136 218 - 465.00 - 0.00
21 315 0.11 102 102 218 - 465.00 - 0.00
22 330 0.13 119 119 218 - 465.00 - 0.00
23 345 0.15 136 136 218 - 465.00 - 0.00
24 360 0.15 136 136 218 - 465.00 - 0.00
25 375 0.17 153 153 218 - 465.00 - 0.00
26 390 0.17 153 153 218 - 465.00 - 0.00
27 405 0.19 170 170 218 - 465.00 - 0.00
28 420 0.19 170 170 218 - 465.00 - 0.00
29 435 0.19 170 170 218 - 465.00 - 0.00
30 450 0.21 187 187 218 - 465.00 - 0.00
31 465 0.23 204 204 218 - 465.00 - 0.00
32 480 0.02 15 15 218 - 465.00 - 0.00
33 495 0.43 386 386 218 168 465.01 168 0.00
34 510 0.46 416 584 218 366 465.02 366 0.01
35 525 0.68 616 982 218 764 465.05 764 0.02
36 540 0.91 816 1,580 218 1,362 465.08 1,362 0.03
37 555 1.32 1,185 2,547 218 2,329 465.14 2,329 0.05
38 570 1.54 1,384 3,714 218 3,496 465.21 3,496 0.08
39 585 1.76 1,583 5,079 218 4,861 465.30 4,861 0.11
40 600 1.98 1,782 6,643 218 6,426 465.39 6,426 0.15
41 615 0.69 620 7,045 218 6,828 465.42 6,828 0.16
42 630 0.72 648 7,475 218 7,257 465.44 7,257 0.17
43 645 1.70 1,526 8,783 218 8,566 465.52 8,566 0.20
44 660 1.73 1,553 10,119 218 9,901 465.61 9,901 0.23
45 675 1.57 1,410 11,311 218 11,094 465.68 11,094 0.25
46 690 1.60 1,437 12,531 218 12,313 465.75 12,313 0.28
47 705 1.25 1,124 13,437 218 13,219 465.81 13,219 0.30
48 720 1.47 1,320 14,539 218 14,321 465.88 14,321 0.33
49 735 2.82 2,537 16,858 218 16,640 466.02 16,640 0.38
50 750 3.04 2,732 19,373 218 19,155 466.16 19,155 0.44
51 765 3.44 3,098 22,253 218 22,035 466.32 22,035 0.51
52 780 3.66 3,293 25,329 218 25,111 466.49 25,111 0.58
53 795 4.63 4,168 29,279 218 29,062 466.71 29,062 0.67
54 810 4.66 4,193 33,254 218 33,037 466.93 33,037 0.76
55 825 2.61 2,346 35,383 218 35,165 467.05 35,165 0.81
56 840 2.63 2,370 37,535 218 37,317 467.16 37,317 0.86
57 855 3.42 3,074 40,391 218 40,173 467.30 40,173 0.92
58 870 3.25 2,927 43,100 218 42,882 467.44 42,882 0.98

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 13 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
59 885 3.28 2,950 45,832 218 45,614 467.58 45,614 1.05
60 900 3.11 2,802 48,417 218 48,199 467.71 48,199 1.11
61 915 2.95 2,654 50,853 218 50,635 467.84 50,635 1.16
62 930 2.78 2,506 53,141 218 52,924 467.95 52,924 1.21
63 945 2.05 1,847 54,771 218 54,553 468.04 54,553 1.25
64 960 2.08 1,868 56,421 218 56,204 468.12 56,204 1.29
65 975 0.08 68 56,272 218 56,054 468.11 56,054 1.29
66 990 0.08 68 56,122 218 55,904 468.10 55,904 1.28
67 1005 0.06 51 55,955 218 55,738 468.09 55,738 1.28
68 1020 0.06 51 55,789 218 55,571 468.08 55,571 1.28
69 1035 0.09 85 55,656 218 55,438 468.08 55,438 1.27
70 1050 0.09 85 55,523 218 55,305 468.07 55,305 1.27
71 1065 0.09 85 55,390 218 55,173 468.07 55,173 1.27
72 1080 0.08 68 55,241 218 55,023 468.06 55,023 1.26
73 1095 0.08 68 55,091 218 54,873 468.05 54,873 1.26
74 1110 0.08 68 54,941 218 54,724 468.04 54,724 1.26
75 1125 0.06 51 54,775 218 54,557 468.04 54,557 1.25
76 1140 0.04 54,591 34 218 54,373 468.03 54,373 1.25
77 1155 0.06 51 54,424 218 54,206 468.02 54,206 1.24
78 1170 0.08 68 54,274 218 54,057 468.01 54,057 1.24
79 1185 0.06 51 54,108 218 53,890 468.00 53,890 1.24
80 1200 0.04 34 53,924 218 53,706 467.99 53,706 1.23
81 1215 0.06 51 53,757 218 53,539 467.99 53,539 1.23
82 1230 0.06 51 53,590 218 53,373 467.98 53,373 1.23
83 1245 0.06 51 53,424 218 53,206 467.97 53,206 1.22
84 1260 0.04 34 53,240 218 53,022 467.96 53,022 1.22
85 1275 0.06 51 53,073 218 52,856 467.95 52,856 1.21
86 1290 0.04 34 52,890 218 52,672 467.94 52,672 1.21
87 1305 0.06 51 52,723 218 52,505 467.93 52,505 1.21
88 1320 0.04 34 52,539 218 52,321 467.92 52,321 1.20
89 1335 0.06 51 52,372 218 52,155 467.92 52,155 1.20
90 1350 0.04 34 52,189 218 51,971 467.91 51,971 1.19
91 1365 0.04 34 52,005 218 51,787 467.90 51,787 1.19
92 1380 0.04 34 51,821 218 51,603 467.89 51,603 1.18
93 1395 0.04 34 51,637 218 51,420 467.88 51,420 1.18
94 1410 0.04 34 51,454 218 51,236 467.87 51,236 1.18
95 1425 0.04 34 51,270 218 51,052 467.86 51,052 1.17
96 1440 0.04 34 51,086 218 50,869 467.85 50,869 1.17
Basin Depth Analysis

Page 14 of 14 ends

Item 33.
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
37 38
39 40
41 42
43 44
45 46
47 48
49 50
51 52
53 54
55 56
AB C D

RCFCD SYNTHETIC UNIT HYDROGRAPH

DATA INPUT SHEET
WORKSHEET PREPARED BY: JAMES R. BAZUA, P.E.

PROJECT NAME CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB #
CONCENTRATION POINT DESIGNATION 1
AREA DESIGNATION SUBAREA 3

TRIBUTARY AREAS ACRES

COMMERCIAL
PAVING/HARDSCAPE 2.56
SF - 1 ACRE
SF - 1/2 ACRE
SF - 1/4 ACRE
MF - CONDOMINIUMS 6.65

MF - APARTMENTS

MOBILE HOME PARK
LANDSCAPING 1.04

RETENTION BASIN

GOLF COURSE

MOUNTAINOUS
LOW LOSS RATE (PERCENT) 90%
LENGTH OF WATERCOURSE (L) 750
LENGTH TO POINT OPPOSITE CENTROID (Lca) 170
ELEVATION OF HEADWATER 471.8
ELEVATION OF CONCENTRATION POINT 468.5
AVERAGE MANNINGS 'N' VALUE 0.02
STORM FREQUENCY (YEAR) 100

POINT RAIN
3-HOUR 2.12
6-HOUR 2.78
24-HOUR 4.47
BASIN CHARACTERISTICS: ELEVATION AREA
465 15000
466 16600
467 18250
468 19960
468.5 20831
PERCOLATION RATE (in/hr) 0.67

DRYWELL DATA

NUMBER USED
PERCOLATION RATE (cfs)

Page 1255 ends

Item 33.

POINT AREA AVERAGE POINT AREA AVERAGE POINT AREA AVERAGE

RAIN POINT RAIN POINT RAIN POINT

INCHES RAIN INCHES RAIN INCHES RAIN
(Plate E-5.2) INCHES (Plate E-5.4) INCHES (Plate E-5.6) INCHES

2.12 10.250 1.00 2.12 2.78 10.250 1.00 2.78 4.47 10.250 1.00 4.47

0.00 0.00 0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00
SUM [5] 10.25 SUM [7] 2.12 SUM [9] 10.25 SUM [11] 2.78 SUM [13] 10.25 SUM [15] 4.47 [16] AREA ADJ FACTOR 1.000 1.000 1.000
[17] ADJ AVG POINT RAIN 2.12 2.78 4.47
DURATION 3-HOUR 6-HOUR 24-HOUR
EFFECTIVE RAIN (in) 1.51 1.59 1.71
FLOOD VOLUME (cu-ft) 56,125 59,056 63,525
(acre-ft) 1.29 1.36 1.46
REQUIRED STORAGE (cu-ft) 53,172 53,709 51,340
(acre-ft) 1.22 1.23 1.18
PEAK FLOW (cfs) 19.27 17.04 4.42
MAXIMUM WSEL (ft) 468.04 468.07 467.95

0.142
170.00

0.001
[12] S^0.5
[13] L*LCA/S^0.5
[14] AVERAGE MANNINGS 'N'
[10] H-FEET 3.3
[11] S-FEET/MILE

PHYSICAL DATA

RAINFALL DATA
[1] CONCENTRATION POINT 1
SUBAREA 3

10.250
750

0.032
471.8
468.5

0.03 2.0

2.0 4.1

23.2 4.82

0.23 STORM EVENT SUMMARY
[17] 100% OF LAG-MINUTES
[18] 200% OF LAG-MINUTES
[24] TOTAL PERCOLATION RATE (cfs)
[19] UNIT TIME-MINUTES (100%-200% OF LAG)
3-HOURS
Plate E-2.1

Page 2 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT CALHOUN AT AVENUE 49 - 100 YEAR EVENT CONCENTRATION POINT: 1BY MES R. BAZUA, P.E. DATE 1/17/2025

ADJUSTED LOSS RATE

SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AVERAGE

GROUP NUMBER AREA PERCENT INFILTRATION ADJUSTED

INFILTRATION OF AREA RATE INFILTRATION

RATE IMPERVIOUS RATE
(in/hr) (in/hr) (in/hr)
[Plate C-1] [Plate E-6.1] [Plate E-6.2] [Plate E-6.3]
B 56 0.52 90% 0.10 0.00 0.000 0.0000
B 56 0.52 100% 0.05 2.56 0.250 0.0130
B 56 0.52 20% 0.43 0.00 0.000 0.0000B 56 0.52 40% 0.33 0.00 0.000 0.0000B 56 0.52 50% 0.29 0.00 0.000 0.0000B 56 0.52 65% 0.22 6.65 0.649 0.1400B 56 0.52 80% 0.15 0.00 0.000 0.0000B 56 0.52 75% 0.17 0.00 0.000 0.0000B 56 0.52 0% 0.52 1.04 0.101 0.0528B 56 0.52 0% 0.52 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.00 0.000 0.0000 D 93 0.95 90% 0.18 0.00 0.000 0.0000

0.00 0.000 0.0000

0.00 0.000 0.0000
SUM 10.25 SUM 0.2058
VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY)Fm= 0.102877561C= 0.00191Ft=C(24-(T/60))^1.55 = 0.00191 0.10 in/hr LOW LOSS RATE (80-90 PERCENT) = 90%Where:T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 +

LAND USE

COMMERCIAL

PAVING/HARDSCAPE
SF - 1 ACRE
SF - 1/2 ACRESF - 1/4 ACRE
MF - COND0MINIUMS

MF - APARTMENTS

MOBILE HOME PARKS

LANDSCAPING

RETENTION BASINS

GOLF COURSE

MOUNTAINOUS
Plate E-2.1

Page 3 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 3 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: MES R. BAZUA, DATE 1/17/2025
DRAINAGE AREA-ACRES 10.25
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 2.05
UNIT TIME-PERCENT OF LAG 244.5
TOTAL ADJUSTED STORM RAIN-INCHES 2.12
CONSTANT LOSS RATE-in/hr 0.21
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.23 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 1.3 0.331 0.21 0.30 0.12 1.28 314.48
2 10 0.17 1.3 0.331 0.21 0.30 0.12 1.28 314.48
3 15 0.25 1.1 0.280 0.21 0.25 0.07 0.76 158.02
4 20 0.33 1.5 0.382 0.21 0.34 0.18 1.80 470.93
5 25 0.42 1.5 0.382 0.21 0.34 0.18 1.80 470.93
6 30 0.50 1.8 0.458 0.21 0.41 0.25 2.58 705.62
7 35 0.58 1.5 0.382 0.21 0.34 0.18 1.80 470.93
8 40 0.67 1.8 0.458 0.21 0.41 0.25 2.58 705.62
9 45 0.75 1.8 0.458 0.21 0.41 0.25 2.58 705.62
10 50 0.83 1.5 0.382 0.21 0.34 0.18 1.80 470.93
11 55 0.92 1.6 0.407 0.21 0.37 0.20 2.06 549.16
12 60 1.00 1.8 0.458 0.21 0.41 0.25 2.58 705.62
13 65 1.08 2.2 0.560 0.21 0.50 0.35 3.63 1018.53
14 70 1.17 2.2 0.560 0.21 0.50 0.35 3.63 1018.53
15 75 1.25 2.2 0.560 0.21 0.50 0.35 3.63 1018.53
16 80 1.33 2.0 0.509 0.21 0.46 0.30 3.11 862.07
17 85 1.42 2.6 0.661 0.21 0.60 0.46 4.67 1331.44
18 90 1.50 2.7 0.687 0.21 0.62 0.48 4.93 1409.67
19 95 1.58 2.4 0.611 0.21 0.55 0.40 4.15 1174.98
20 100 1.67 2.7 0.687 0.21 0.62 0.48 4.93 1409.67
21 105 1.75 3.3 0.840 0.21 0.76 0.63 6.50 1879.04
22 110 1.83 3.1 0.789 0.21 0.71 0.58 5.97 1722.58
23 115 1.92 2.9 0.738 0.21 0.66 0.53 5.45 1566.12
24 120 2.00 3.0 0.763 0.21 0.69 0.56 5.71 1644.35
25 125 2.08 3.1 0.789 0.21 0.71 0.58 5.97 1722.58
26 130 2.17 4.2 1.068 0.21 0.96 0.86 8.84 2583.09
27 135 2.25 5.0 1.272 0.21 1.14 1.07 10.93 3208.91
28 140 2.33 3.5 0.890 0.21 0.80 0.68 7.02 2035.49
29 145 2.42 6.8 1.730 0.21 1.56 1.52 15.62 4617.02
30 150 2.50 7.3 1.857 0.21 1.67 1.65 16.93 5008.16
31 155 2.58 8.2 2.086 0.21 1.88 1.88 19.27 5712.21
32 160 2.67 5.9 1.501 0.21 1.35 1.30 13.28 3912.96
33 165 2.75 2.0 0.509 0.21 0.46 0.30 3.11 862.07
34 170 2.83 1.8 0.458 0.21 0.41 0.25 2.58 705.62
35 175 2.92 1.8 0.458 0.21 0.41 0.25 2.58 705.62
36 180 3.00 0.6 0.153 0.21 0.14 0.02 0.16 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.51
FLOOD VOLUME (acft) 1.29
FLOOD VOLUME (cuft) 56125.24
REQUIRED STORAGE (acft) 1.22
REQUIRED STORAGE (cuft) 53171.53
PEAK FLOW RATE (cfs) 19.27
Loss Rate
in/hr
Time

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 4 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 6 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 10.25
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 2.05
UNIT TIME-PERCENT OF LAG 244.5
TOTAL ADJUSTED STORM RAIN-INCHES 2.78
CONSTANT LOSS RATE-in/hr 0.206
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.23 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 0.5 0.167 0.21 0.15 0.02 0.17 0.00
2 10 0.17 0.6 0.200 0.21 0.18 0.02 0.21 0.00
3 15 0.25 0.6 0.200 0.21 0.18 0.02 0.21 0.00
4 20 0.33 0.6 0.200 0.21 0.18 0.02 0.21 0.00
5 25 0.42 0.6 0.200 0.21 0.18 0.02 0.21 0.00
6 30 0.50 0.7 0.234 0.21 0.21 0.03 0.28 15.59
7 35 0.58 0.7 0.234 0.21 0.21 0.03 0.28 15.59
8 40 0.67 0.7 0.234 0.21 0.21 0.03 0.28 15.59
9 45 0.75 0.7 0.234 0.21 0.21 0.03 0.28 15.59
10 50 0.83 0.7 0.234 0.21 0.21 0.03 0.28 15.59
11 55 0.92 0.7 0.234 0.21 0.21 0.03 0.28 15.59
12 60 1.00 0.8 0.267 0.21 0.24 0.06 0.63 118.17
13 65 1.08 0.8 0.267 0.21 0.24 0.06 0.63 118.17
14 70 1.17 0.8 0.267 0.21 0.24 0.06 0.63 118.17
15 75 1.25 0.8 0.267 0.21 0.24 0.06 0.63 118.17
16 80 1.33 0.8 0.267 0.21 0.24 0.06 0.63 118.17
17 85 1.42 0.8 0.267 0.21 0.24 0.06 0.63 118.17
18 90 1.50 0.8 0.267 0.21 0.24 0.06 0.63 118.17
19 95 1.58 0.8 0.267 0.21 0.24 0.06 0.63 118.17
20 100 1.67 0.8 0.267 0.21 0.24 0.06 0.63 118.17
21 105 1.75 0.8 0.267 0.21 0.24 0.06 0.63 118.17
22 110 1.83 0.8 0.267 0.21 0.24 0.06 0.63 118.17
23 115 1.92 0.8 0.267 0.21 0.24 0.06 0.63 118.17
24 120 2.00 0.9 0.300 0.21 0.27 0.09 0.97 220.75
25 125 2.08 0.8 0.267 0.21 0.24 0.06 0.63 118.17
26 130 2.17 0.9 0.300 0.21 0.27 0.09 0.97 220.75
27 135 2.25 0.9 0.300 0.21 0.27 0.09 0.97 220.75
28 140 2.33 0.9 0.300 0.21 0.27 0.09 0.97 220.75
29 145 2.42 0.9 0.300 0.21 0.27 0.09 0.97 220.75
30 150 2.50 0.9 0.300 0.21 0.27 0.09 0.97 220.75
31 155 2.58 0.9 0.300 0.21 0.27 0.09 0.97 220.75
32 160 2.67 0.9 0.300 0.21 0.27 0.09 0.97 220.75
33 165 2.75 1.0 0.334 0.21 0.30 0.13 1.31 323.33
34 170 2.83 1.0 0.334 0.21 0.30 0.13 1.31 323.33
35 175 2.92 1.0 0.334 0.21 0.30 0.13 1.31 323.33
36 180 3.00 1.0 0.334 0.21 0.30 0.13 1.31 323.33
37 185 3.08 1.0 0.334 0.21 0.30 0.13 1.31 323.33
38 190 3.17 1.1 0.367 0.21 0.33 0.16 1.65 425.91
39 195 3.25 1.1 0.367 0.21 0.33 0.16 1.65 425.91
40 200 3.33 1.1 0.367 0.21 0.33 0.16 1.65 425.91
41 205 3.42 1.2 0.400 0.21 0.36 0.19 1.99 528.50
42 210 3.50 1.3 0.434 0.21 0.39 0.23 2.34 631.08
43 215 3.58 1.4 0.467 0.21 0.42 0.26 2.68 733.66
44 220 3.67 1.4 0.467 0.21 0.42 0.26 2.68 733.66
45 225 3.75 1.5 0.500 0.21 0.45 0.29 3.02 836.24
46 230 3.83 1.5 0.500 0.21 0.45 0.29 3.02 836.24
47 235 3.92 1.6 0.534 0.21 0.48 0.33 3.36 938.82
48 240 4.00 1.6 0.534 0.21 0.48 0.33 3.36 938.82
49 245 4.08 1.7 0.567 0.21 0.51 0.36 3.70 1041.41
50 250 4.17 1.8 0.600 0.21 0.54 0.39 4.05 1143.99
51 255 4.25 1.9 0.634 0.21 0.57 0.43 4.39 1246.57
52 260 4.33 2.0 0.667 0.21 0.60 0.46 4.73 1349.15
53 265 4.42 2.1 0.701 0.21 0.63 0.49 5.07 1451.73
54 270 4.50 2.1 0.701 0.21 0.63 0.49 5.07 1451.73
55 275 4.58 2.2 0.734 0.21 0.66 0.53 5.41 1554.32
56 280 4.67 2.3 0.767 0.21 0.69 0.56 5.76 1656.90

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
Plate E-2.2

Page 5 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
57 285 4.75 2.4 0.801 0.21 0.72 0.59 6.10 1759.48
58 290 4.83 2.4 0.801 0.21 0.72 0.59 6.10 1759.48
59 295 4.92 2.5 0.834 0.21 0.75 0.63 6.44 1862.06
60 300 5.00 2.6 0.867 0.21 0.78 0.66 6.78 1964.64
61 305 5.08 3.1 1.034 0.21 0.93 0.83 8.49 2477.55
62 310 5.17 3.6 1.201 0.21 1.08 1.00 10.20 2990.46
63 315 5.25 3.9 1.301 0.21 1.17 1.10 11.23 3298.21
64 320 5.33 4.2 1.401 0.21 1.26 1.20 12.25 3605.96
65 325 5.42 4.7 1.568 0.21 1.41 1.36 13.96 4118.87
66 330 5.50 5.6 1.868 0.21 1.68 1.66 17.04 5042.10
67 335 5.58 1.9 0.634 0.21 0.57 0.43 4.39 1246.57
68 340 5.67 0.9 0.300 0.21 0.27 0.09 0.97 220.75
69 345 5.75 0.6 0.200 0.21 0.18 0.02 0.21 0.00
70 350 5.83 0.5 0.167 0.21 0.15 0.02 0.17 0.00
71 355 5.92 0.3 0.100 0.21 0.09 0.01 0.10 0.00
72 360 6.00 0.2 0.067 0.21 0.06 0.01 0.07 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.59
FLOOD VOLUME (acft) 1.36
FLOOD VOLUME (cuft) 59055.81
REQUIRED STORAGE (acft) 1.23
REQUIRED STORAGE (cuft) 53709.02
PEAK FLOW RATE (cfs) 17.04
Plate E-2.2

Page 6 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 24 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 10.250 CONSTANT LOSS RATE-in/hr n/a UNIT TIME-MINUTES 15 VARIABLE LOSS RATE (AVG) in/hr 0.2058 LAG TIME - MINUTES 2.05 MINIMUM LOSS RATE (for var. loss) - in/hr 0.103 UNIT TIME-PERCENT OF LAG 733.4 LOW LOSS RATE - DECIMAL 0.90 TOTAL ADJUSTED STORM RAIN-INCHES 4.47 C 0.00191
PERCOLATION RATE (cfs) 0.23
Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 15 0.25 0.2 0.036 0.363 0.032 0.004 0.04 0.00
2 30 0.50 0.3 0.054 0.359 0.048 0.005 0.05 0.00
3 45 0.75 0.3 0.054 0.355 0.048 0.005 0.05 0.00
4 60 1.00 0.4 0.072 0.351 0.064 0.007 0.07 0.00
5 75 1.25 0.3 0.054 0.347 0.048 0.005 0.05 0.00
6 90 1.50 0.3 0.054 0.343 0.048 0.005 0.05 0.00
7 105 1.75 0.3 0.054 0.338 0.048 0.005 0.05 0.00
8 120 2.00 0.4 0.072 0.334 0.064 0.007 0.07 0.00
9 135 2.25 0.4 0.072 0.330 0.064 0.007 0.07 0.00
10 150 2.50 0.4 0.072 0.326 0.064 0.007 0.07 0.00
11 165 2.75 0.5 0.089 0.322 0.080 0.009 0.09 0.00
12 180 3.00 0.5 0.089 0.318 0.080 0.009 0.09 0.00
13 195 3.25 0.5 0.089 0.314 0.080 0.009 0.09 0.00
14 210 3.50 0.5 0.089 0.310 0.080 0.009 0.09 0.00
15 225 3.75 0.5 0.089 0.307 0.080 0.009 0.09 0.00
16 240 4.00 0.6 0.107 0.303 0.097 0.011 0.11 0.00
17 255 4.25 0.6 0.107 0.299 0.097 0.011 0.11 0.00
18 270 4.50 0.7 0.125 0.295 0.113 0.013 0.13 0.00
19 285 4.75 0.7 0.125 0.291 0.113 0.013 0.13 0.00
20 300 5.00 0.8 0.143 0.288 0.129 0.014 0.15 0.00
21 315 5.25 0.6 0.107 0.284 0.097 0.011 0.11 0.00
22 330 5.50 0.7 0.125 0.280 0.113 0.013 0.13 0.00
23 345 5.75 0.8 0.143 0.276 0.129 0.014 0.15 0.00
24 360 6.00 0.8 0.143 0.273 0.129 0.014 0.15 0.00
25 375 6.25 0.9 0.161 0.269 0.145 0.016 0.16 0.00
26 390 6.50 0.9 0.161 0.266 0.145 0.016 0.16 0.00
27 405 6.75 1.0 0.179 0.262 0.161 0.018 0.18 0.00
28 420 7.00 1.0 0.179 0.258 0.161 0.018 0.18 0.00
29 435 7.25 1.0 0.179 0.255 0.161 0.018 0.18 0.00
30 450 7.50 1.1 0.197 0.252 0.177 0.020 0.20 0.00
31 465 7.75 1.2 0.215 0.248 0.193 0.021 0.22 0.00
32 480 8.00 1.3 0.232 0.245 0.209 0.023 0.24 5.05
33 495 8.25 1.5 0.268 0.241 0.241 0.027 0.28 39.29
34 510 8.50 1.5 0.268 0.238 0.241 0.030 0.31 70.31
35 525 8.75 1.6 0.286 0.235 0.257 0.052 0.53 266.00
36 540 9.00 1.7 0.304 0.231 0.274 0.073 0.75 461.42
37 555 9.25 1.9 0.340 0.228 0.306 0.112 1.15 821.51
38 570 9.50 2.0 0.358 0.225 0.322 0.133 1.36 1016.37
39 585 9.75 2.1 0.375 0.222 0.338 0.154 1.58 1210.96
40 600 10.00 2.2 0.393 0.218 0.354 0.175 1.79 1405.26
41 615 10.25 1.5 0.268 0.215 0.241 0.053 0.54 279.74
42 630 10.50 1.5 0.268 0.212 0.241 0.056 0.58 308.53
43 645 10.75 2.0 0.358 0.209 0.322 0.149 1.52 1161.74
44 660 11.00 2.0 0.358 0.206 0.322 0.152 1.55 1189.95
45 675 11.25 1.9 0.340 0.203 0.306 0.137 1.40 1052.92
46 690 11.50 1.9 0.340 0.200 0.306 0.140 1.43 1080.54
47 705 11.75 1.7 0.304 0.197 0.274 0.107 1.10 777.97
48 720 12.00 1.8 0.322 0.194 0.290 0.128 1.31 969.93
49 735 12.25 2.5 0.447 0.191 0.402 0.256 2.62 2151.25
50 750 12.50 2.6 0.465 0.188 0.418 0.277 2.84 2342.59
51 765 12.75 2.8 0.501 0.185 0.451 0.315 3.23 2698.57
52 780 13.00 2.9 0.519 0.183 0.467 0.336 3.44 2889.30
53 795 13.25 3.4 0.608 0.180 0.547 0.428 4.39 3739.48
54 810 13.50 3.4 0.608 0.177 0.547 0.431 4.42 3764.62
55 825 13.75 2.3 0.411 0.174 0.370 0.237 2.43 1975.07
56 840 14.00 2.3 0.411 0.172 0.370 0.239 2.45 1999.56
57 855 14.25 2.7 0.483 0.169 0.434 0.314 3.21 2683.50
58 870 14.50 2.6 0.465 0.167 0.418 0.298 3.06 2542.39
59 885 14.75 2.6 0.465 0.164 0.418 0.301 3.08 2565.88
60 900 15.00 2.5 0.447 0.162 0.402 0.285 2.93 2424.08
61 915 15.25 2.4 0.429 0.159 0.386 0.270 2.77 2281.94
62 930 15.50 2.3 0.411 0.157 0.370 0.255 2.61 2139.45
63 945 15.75 1.9 0.340 0.154 0.306 0.185 1.90 1501.78
64 960 16.00 1.9 0.340 0.152 0.306 0.188 1.93 1523.52
65 975 16.25 0.4 0.072 0.150 0.064 0.007 0.07 0.00
66 990 16.50 0.4 0.072 0.147 0.064 0.007 0.07 0.00
67 1005 16.75 0.3 0.054 0.145 0.048 0.005 0.05 0.00
Time Loss Rate
in/hr

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 7 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
68 1020 17.00 0.3 0.054 0.143 0.048 0.005 0.05 0.00
69 1035 17.25 0.5 0.089 0.141 0.080 0.009 0.09 0.00
70 1050 17.50 0.5 0.089 0.139 0.080 0.009 0.09 0.00
71 1065 17.75 0.5 0.089 0.137 0.080 0.009 0.09 0.00
72 1080 18.00 0.4 0.072 0.134 0.064 0.007 0.07 0.00
73 1095 18.25 0.4 0.072 0.133 0.064 0.007 0.07 0.00
74 1110 18.50 0.4 0.072 0.131 0.064 0.007 0.07 0.00
75 1125 18.75 0.3 0.054 0.129 0.048 0.005 0.05 0.00
76 1140 19.00 0.2 0.036 0.127 0.032 0.004 0.04 0.00
77 1155 19.25 0.3 0.054 0.125 0.048 0.005 0.05 0.00
78 1170 19.50 0.4 0.072 0.123 0.064 0.007 0.07 0.00
79 1185 19.75 0.3 0.054 0.122 0.048 0.005 0.05 0.00
80 1200 20.00 0.2 0.036 0.120 0.032 0.004 0.04 0.00
81 1215 20.25 0.3 0.054 0.118 0.048 0.005 0.05 0.00
82 1230 20.50 0.3 0.054 0.117 0.048 0.005 0.05 0.00
83 1245 20.75 0.3 0.054 0.115 0.048 0.005 0.05 0.00
84 1260 21.00 0.2 0.036 0.114 0.032 0.004 0.04 0.00
85 1275 21.25 0.3 0.054 0.113 0.048 0.005 0.05 0.00
86 1290 21.50 0.2 0.036 0.111 0.032 0.004 0.04 0.00
87 1305 21.75 0.3 0.054 0.110 0.048 0.005 0.05 0.00
88 1320 22.00 0.2 0.036 0.109 0.032 0.004 0.04 0.00
89 1335 22.25 0.3 0.054 0.108 0.048 0.005 0.05 0.00
90 1350 22.50 0.2 0.036 0.107 0.032 0.004 0.04 0.00
91 1365 22.75 0.2 0.036 0.106 0.032 0.004 0.04 0.00
92 1380 23.00 0.2 0.036 0.105 0.032 0.004 0.04 0.00
93 1395 23.25 0.2 0.036 0.104 0.032 0.004 0.04 0.00
94 1410 23.50 0.2 0.036 0.104 0.032 0.004 0.04 0.00
95 1425 23.75 0.2 0.036 0.103 0.032 0.004 0.04 0.00
96 1440 24.00 0.2 0.036 0.103 0.032 0.004 0.04 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.71
FLOOD VOLUME (acft) 1.46
FLOOD VOLUME (cuft) 63525.46
REQUIRED STORAGE (acft) 1.18
REQUIRED STORAGE (cuft) 51340.48
PEAK FLOW (cfs) 4.42
Plate E-2.2

Page 8 of 14 ends

Item 33.

PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB # 0
1 BASIN CHARACTERISTICS

CONTOUR DEPTH AREA VOLUME

INCR TOTAL INCR TOTAL INCR TOTAL
(ft) (ft) (sf) (sf) (cuft) (cuft) (acre-ft)
465 0 0 15000 0 0 0.00
466 1 1 1600 16600 15800 15800 0.36
467 1 2 1650 18250 17425 33225 0.76
468 1 3 1710 19960 19105 52330 1.20
468.5 0.5 3.5 871 20831 10198 62528 1.44

PERCOLATION CALCULATIONS
PERCOLATION RATE 0.67 in/hr 0.23 cfs

MAXWELL IV DRYWELLS
NUMBER USED 0
RATE/DRYWELL 0 cfs
TOTAL DISSIPATED 0 cfs
TOTAL PERCOLATION RATE 0.23 cfs
Basin Characteristics

Page 9 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 3 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 1.28 384 384 70 314 465.02 314 0.01
2 10 1.28 384 699 70 629 465.04 629 0.01
3 15 0.76 228 857 70 787 465.05 787 0.02
4 20 1.80 541 1,328 70 1,258 465.08 1,258 0.03
5 25 1.80 541 1,799 70 1,729 465.11 1,729 0.04
6 30 2.58 775 2,504 70 2,434 465.15 2,434 0.06
7 35 1.80 541 2,975 70 2,905 465.18 2,905 0.07
8 40 2.58 775 3,681 70 3,611 465.23 3,611 0.08
9 45 2.58 775 4,386 70 4,317 465.27 4,317 0.10
10 50 1.80 541 4,857 70 4,788 465.30 4,788 0.11
11 55 2.06 619 5,406 70 5,337 465.34 5,337 0.12
12 60 2.58 775 6,112 70 6,042 465.38 6,042 0.14
13 65 3.63 1,088 7,131 70 7,061 465.45 7,061 0.16
14 70 3.63 1,088 8,149 70 8,079 465.51 8,079 0.19
15 75 3.63 1,088 9,168 70 9,098 465.58 9,098 0.21
16 80 3.11 932 10,030 70 9,960 465.63 9,960 0.23
17 85 4.67 1,401 11,361 70 11,291 465.71 11,291 0.26
18 90 4.93 1,479 12,771 70 12,701 465.80 12,701 0.29
19 95 4.15 1,245 13,946 70 13,876 465.88 13,876 0.32
20 100 4.93 1,479 15,356 70 15,286 465.97 15,286 0.35
21 105 6.50 1,949 17,235 70 17,165 466.08 17,165 0.39
22 110 5.97 1,792 18,957 70 18,887 466.18 18,887 0.43
23 115 5.45 1,636 20,523 70 20,453 466.27 20,453 0.47
24 120 5.71 1,714 22,168 70 22,098 466.36 22,098 0.51
25 125 5.97 1,792 23,890 70 23,820 466.46 23,820 0.55
26 130 8.84 2,653 26,473 70 26,403 466.61 26,403 0.61
27 135 10.93 3,279 29,682 70 29,612 466.79 29,612 0.68
28 140 7.02 2,105 31,718 70 31,648 466.91 31,648 0.73
29 145 15.62 4,687 36,335 70 36,265 467.16 36,265 0.83
30 150 16.93 5,078 41,343 70 41,273 467.42 41,273 0.95
31 155 19.27 5,782 47,055 70 46,985 467.72 46,985 1.08
32 160 13.28 3,983 50,968 70 50,898 467.93 50,898 1.17
33 165 3.11 932 51,830 70 51,760 467.97 51,760 1.19
34 170 2.58 775 52,536 70 52,466 468.01 52,466 1.20
35 175 2.58 775 53,241 70 53,172 468.04 53,172 1.22
36 180 0.16 47 53,218 70 53,149 468.04 53,149 1.22

BALANCE IN
BASIN
TIME
Basin Depth Analysis

Page 10 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.17 51 51 70 - 465.00 - 0.00
2 10 0.21 62 62 70 - 465.00 - 0.00
3 15 0.21 62 62 70 - 465.00 - 0.00
4 20 0.21 62 62 70 - 465.00 - 0.00
5 25 0.21 62 62 70 - 465.00 - 0.00
6 30 0.28 85 85 70 16 465.00 16 0.00
7 35 0.28 85 101 70 31 465.00 31 0.00
8 40 0.28 85 117 70 47 465.00 47 0.00
9 45 0.28 85 132 70 62 465.00 62 0.00
10 50 0.28 85 148 70 78 465.00 78 0.00
11 55 0.28 85 163 70 94 465.01 94 0.00
12 60 0.63 188 281 70 212 465.01 212 0.00
13 65 0.63 188 400 70 330 465.02 330 0.01
14 70 0.63 188 518 70 448 465.03 448 0.01
15 75 0.63 188 636 70 566 465.04 566 0.01
16 80 0.63 188 754 70 684 465.04 684 0.02
17 85 0.63 188 872 70 803 465.05 803 0.02
18 90 0.63 188 990 70 921 465.06 921 0.02
19 95 0.63 188 1,109 70 1,039 465.07 1,039 0.02
20 100 0.63 188 1,227 70 1,157 465.07 1,157 0.03
21 105 0.63 188 1,345 70 1,275 465.08 1,275 0.03
22 110 0.63 188 1,463 70 1,393 465.09 1,393 0.03
23 115 0.63 188 1,581 70 1,512 465.10 1,512 0.03
24 120 0.97 291 1,802 70 1,732 465.11 1,732 0.04
25 125 0.63 188 1,920 70 1,850 465.12 1,850 0.04
26 130 0.97 291 2,141 70 2,071 465.13 2,071 0.05
27 135 0.97 291 2,362 70 2,292 465.15 2,292 0.05
28 140 0.97 291 2,582 70 2,513 465.16 2,513 0.06
29 145 0.97 291 2,803 70 2,733 465.17 2,733 0.06
30 150 0.97 291 3,024 70 2,954 465.19 2,954 0.07
31 155 0.97 291 3,245 70 3,175 465.20 3,175 0.07
32 160 0.97 291 3,465 70 3,396 465.21 3,396 0.08
33 165 1.31 393 3,789 70 3,719 465.24 3,719 0.09
34 170 1.31 393 4,112 70 4,042 465.26 4,042 0.09
35 175 1.31 393 4,435 70 4,366 465.28 4,366 0.10
36 180 1.31 393 4,759 70 4,689 465.30 4,689 0.11
37 185 1.31 393 5,082 70 5,012 465.32 5,012 0.12
38 190 1.65 496 5,508 70 5,438 465.34 5,438 0.12
39 195 1.65 496 5,934 70 5,864 465.37 5,864 0.13
40 200 1.65 496 6,360 70 6,290 465.40 6,290 0.14
41 205 1.99 598 6,888 70 6,819 465.43 6,819 0.16
42 210 2.34 701 7,519 70 7,450 465.47 7,450 0.17
43 215 2.68 803 8,253 70 8,183 465.52 8,183 0.19
44 220 2.68 803 8,987 70 8,917 465.56 8,917 0.20
45 225 3.02 906 9,823 70 9,753 465.62 9,753 0.22
46 230 3.02 906 10,659 70 10,589 465.67 10,589 0.24
47 235 3.36 1,009 11,598 70 11,528 465.73 11,528 0.26
48 240 3.36 1,009 12,537 70 12,467 465.79 12,467 0.29
49 245 3.70 1,111 13,578 70 13,509 465.85 13,509 0.31
50 250 4.05 1,214 14,722 70 14,652 465.93 14,652 0.34
51 255 4.39 1,316 15,969 70 15,899 466.01 15,899 0.36
52 260 4.73 1,419 17,318 70 17,248 466.08 17,248 0.40
53 265 5.07 1,522 18,770 70 18,700 466.17 18,700 0.43
54 270 5.07 1,522 20,221 70 20,152 466.25 20,152 0.46
55 275 5.41 1,624 21,776 70 21,706 466.34 21,706 0.50

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 11 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
56 280 5.76 1,727 23,433 70 23,363 466.43 23,363 0.54
57 285 6.10 1,829 25,192 70 25,122 466.53 25,122 0.58
58 290 6.10 1,829 26,952 70 26,882 466.64 26,882 0.62
59 295 6.44 1,932 28,814 70 28,744 466.74 28,744 0.66
60 300 6.78 2,034 30,778 70 30,709 466.86 30,709 0.70
61 305 8.49 2,547 33,256 70 33,186 467.00 33,186 0.76
62 310 10.20 3,060 36,246 70 36,177 467.15 36,177 0.83
63 315 11.23 3,368 39,545 70 39,475 467.33 39,475 0.91
64 320 12.25 3,676 43,151 70 43,081 467.52 43,081 0.99
65 325 13.96 4,189 47,269 70 47,200 467.73 47,200 1.08
66 330 17.04 5,112 52,311 70 52,242 468.00 52,242 1.20
67 335 4.39 1,316 53,558 70 53,488 468.06 53,488 1.23
68 340 0.97 291 53,779 70 53,709 468.07 53,709 1.23
69 345 0.21 62 53,771 70 53,701 468.07 53,701 1.23
70 350 0.17 51 53,752 70 53,682 468.07 53,682 1.23
71 355 0.10 31 53,713 70 53,643 468.06 53,643 1.23
72 360 0.07 21 53,664 70 53,594 468.06 53,594 1.23
Basin Depth Analysis

Page 12 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 15 0.04 33 33 209 - 465.00 - 0.00
2 30 0.05 49 49 209 - 465.00 - 0.00
3 45 0.05 49 49 209 - 465.00 - 0.00
4 60 0.07 66 66 209 - 465.00 - 0.00
5 75 0.05 49 49 209 - 465.00 - 0.00
6 90 0.05 49 49 209 - 465.00 - 0.00
7 105 0.05 49 49 209 - 465.00 - 0.00
8 120 0.07 66 66 209 - 465.00 - 0.00
9 135 0.07 66 66 209 - 465.00 - 0.00
10 150 0.07 66 66 209 - 465.00 - 0.00
11 165 0.09 82 82 209 - 465.00 - 0.00
12 180 0.09 82 82 209 - 465.00 - 0.00
13 195 0.09 82 82 209 - 465.00 - 0.00
14 210 0.09 82 82 209 - 465.00 - 0.00
15 225 0.09 82 82 209 - 465.00 - 0.00
16 240 0.11 99 99 209 - 465.00 - 0.00
17 255 0.11 99 99 209 - 465.00 - 0.00
18 270 0.13 115 115 209 - 465.00 - 0.00
19 285 0.13 115 115 209 - 465.00 - 0.00
20 300 0.15 132 132 209 - 465.00 - 0.00
21 315 0.11 99 99 209 - 465.00 - 0.00
22 330 0.13 115 115 209 - 465.00 - 0.00
23 345 0.15 132 132 209 - 465.00 - 0.00
24 360 0.15 132 132 209 - 465.00 - 0.00
25 375 0.16 148 148 209 - 465.00 - 0.00
26 390 0.16 148 148 209 - 465.00 - 0.00
27 405 0.18 165 165 209 - 465.00 - 0.00
28 420 0.18 165 165 209 - 465.00 - 0.00
29 435 0.18 165 165 209 - 465.00 - 0.00
30 450 0.20 181 181 209 - 465.00 - 0.00
31 465 0.22 198 198 209 - 465.00 - 0.00
32 480 0.24 214 214 209 5 465.00 5 0.00
33 495 0.28 249 254 209 44 465.00 44 0.00
34 510 0.31 280 324 209 115 465.01 115 0.00
35 525 0.53 475 590 209 381 465.02 381 0.01
36 540 0.75 671 1,051 209 842 465.05 842 0.02
37 555 1.15 1,031 1,873 209 1,664 465.11 1,664 0.04
38 570 1.36 1,226 2,889 209 2,680 465.17 2,680 0.06
39 585 1.58 1,420 4,100 209 3,891 465.25 3,891 0.09
40 600 1.79 1,615 5,506 209 5,296 465.34 5,296 0.12
41 615 0.54 489 5,785 209 5,576 465.35 5,576 0.13
42 630 0.58 518 6,094 209 5,884 465.37 5,884 0.14
43 645 1.52 1,371 7,256 209 7,046 465.45 7,046 0.16
44 660 1.55 1,399 8,446 209 8,236 465.52 8,236 0.19
45 675 1.40 1,262 9,498 209 9,289 465.59 9,289 0.21
46 690 1.43 1,290 10,579 209 10,370 465.66 10,370 0.24
47 705 1.10 987 11,357 209 11,148 465.71 11,148 0.26
48 720 1.31 1,179 12,327 209 12,117 465.77 12,117 0.28
49 735 2.62 2,361 14,478 209 14,269 465.90 14,269 0.33
50 750 2.84 2,552 16,821 209 16,611 466.05 16,611 0.38
51 765 3.23 2,908 19,519 209 19,310 466.20 19,310 0.44
52 780 3.44 3,099 22,409 209 22,199 466.37 22,199 0.51
53 795 4.39 3,949 26,148 209 25,939 466.58 25,939 0.60
54 810 4.42 3,974 29,913 209 29,703 466.80 29,703 0.68
55 825 2.43 2,184 31,888 209 31,678 466.91 31,678 0.73
56 840 2.45 2,209 33,887 209 33,678 467.02 33,678 0.77
57 855 3.21 2,893 36,571 209 36,361 467.16 36,361 0.83
58 870 3.06 2,752 39,113 209 38,904 467.30 38,904 0.89

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 13 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
59 885 3.08 2,775 41,679 209 41,470 467.43 41,470 0.95
60 900 2.93 2,633 44,103 209 43,894 467.56 43,894 1.01
61 915 2.77 2,491 46,385 209 46,176 467.68 46,176 1.06
62 930 2.61 2,349 48,525 209 48,315 467.79 48,315 1.11
63 945 1.90 1,711 50,026 209 49,817 467.87 49,817 1.14
64 960 1.93 1,733 51,550 209 51,340 467.95 51,340 1.18
65 975 0.07 66 51,406 209 51,197 467.94 51,197 1.18
66 990 0.07 66 51,263 209 51,054 467.93 51,054 1.17
67 1005 0.05 49 51,103 209 50,894 467.92 50,894 1.17
68 1020 0.05 49 50,943 209 50,734 467.92 50,734 1.16
69 1035 0.09 82 50,816 209 50,607 467.91 50,607 1.16
70 1050 0.09 82 50,689 209 50,480 467.90 50,480 1.16
71 1065 0.09 82 50,563 209 50,353 467.90 50,353 1.16
72 1080 0.07 66 50,419 209 50,210 467.89 50,210 1.15
73 1095 0.07 66 50,276 209 50,066 467.88 50,066 1.15
74 1110 0.07 66 50,132 209 49,923 467.87 49,923 1.15
75 1125 0.05 49 49,972 209 49,763 467.87 49,763 1.14
76 1140 0.04 49,796 33 209 49,587 467.86 49,587 1.14
77 1155 0.05 49 49,636 209 49,427 467.85 49,427 1.13
78 1170 0.07 66 49,493 209 49,283 467.84 49,283 1.13
79 1185 0.05 49 49,333 209 49,124 467.83 49,124 1.13
80 1200 0.04 33 49,157 209 48,947 467.82 48,947 1.12
81 1215 0.05 49 48,997 209 48,787 467.81 48,787 1.12
82 1230 0.05 49 48,837 209 48,627 467.81 48,627 1.12
83 1245 0.05 49 48,677 209 48,467 467.80 48,467 1.11
84 1260 0.04 33 48,500 209 48,291 467.79 48,291 1.11
85 1275 0.05 49 48,341 209 48,131 467.78 48,131 1.10
86 1290 0.04 33 48,164 209 47,955 467.77 47,955 1.10
87 1305 0.05 49 48,004 209 47,795 467.76 47,795 1.10
88 1320 0.04 33 47,828 209 47,619 467.75 47,619 1.09
89 1335 0.05 49 47,668 209 47,459 467.75 47,459 1.09
90 1350 0.04 33 47,492 209 47,282 467.74 47,282 1.09
91 1365 0.04 33 47,315 209 47,106 467.73 47,106 1.08
92 1380 0.04 33 47,139 209 46,929 467.72 46,929 1.08
93 1395 0.04 33 46,962 209 46,753 467.71 46,753 1.07
94 1410 0.04 33 46,786 209 46,577 467.70 46,577 1.07
95 1425 0.04 33 46,610 209 46,400 467.69 46,400 1.07
96 1440 0.04 33 46,433 209 46,224 467.68 46,224 1.06
Basin Depth Analysis

Page 14 of 14 ends

Item 33.
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
37 38
39 40
41 42
43 44
45 46
47 48
49 50
51 52
53 54
55 56
AB C D

RCFCD SYNTHETIC UNIT HYDROGRAPH

DATA INPUT SHEET
WORKSHEET PREPARED BY: JAMES R. BAZUA, P.E.

PROJECT NAME CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB #
CONCENTRATION POINT DESIGNATION 1
AREA DESIGNATION SUBAREA 4

TRIBUTARY AREAS ACRES

COMMERCIAL
PAVING/HARDSCAPE 2.33
SF - 1 ACRE
SF - 1/2 ACRE
SF - 1/4 ACRE
MF - CONDOMINIUMS 6.56

MF - APARTMENTS

MOBILE HOME PARK
LANDSCAPING 0.9

RETENTION BASIN

GOLF COURSE

MOUNTAINOUS
LOW LOSS RATE (PERCENT) 90%
LENGTH OF WATERCOURSE (L) 620
LENGTH TO POINT OPPOSITE CENTROID (Lca) 70
ELEVATION OF HEADWATER 470.5
ELEVATION OF CONCENTRATION POINT 468
AVERAGE MANNINGS 'N' VALUE 0.02
STORM FREQUENCY (YEAR) 100

POINT RAIN
3-HOUR 2.12
6-HOUR 2.78
24-HOUR 4.47
BASIN CHARACTERISTICS: ELEVATION AREA
464.5 13730
465.5 15200
466.5 16700
467.5 18270
468 19075
PERCOLATION RATE (in/hr) 0.67

DRYWELL DATA

NUMBER USED
PERCOLATION RATE (cfs)

Page 1269 ends

Item 33.

POINT AREA AVERAGE POINT AREA AVERAGE POINT AREA AVERAGE

RAIN POINT RAIN POINT RAIN POINT

INCHES RAIN INCHES RAIN INCHES RAIN
(Plate E-5.2) INCHES (Plate E-5.4) INCHES (Plate E-5.6) INCHES

2.12 9.790 1.00 2.12 2.78 9.790 1.00 2.78 4.47 9.790 1.00 4.47

0.00 0.00 0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00
SUM [5] 9.79 SUM [7] 2.12 SUM [9] 9.79 SUM [11] 2.78 SUM [13] 9.79 SUM [15] 4.47 [16] AREA ADJ FACTOR 1.000 1.000 1.000
[17] ADJ AVG POINT RAIN 2.12 2.78 4.47
DURATION 3-HOUR 6-HOUR 24-HOUR
EFFECTIVE RAIN (in) 1.51 1.59 1.71
FLOOD VOLUME (cu-ft) 53,707 56,587 60,936
(acre-ft) 1.23 1.30 1.40
REQUIRED STORAGE (cu-ft) 50,983 51,654 49,570
(acre-ft) 1.17 1.19 1.14
PEAK FLOW (cfs) 18.42 16.28 4.23
MAXIMUM WSEL (ft) 467.67 467.70 467.59
24-HOURS
[15] LAG TIME-HOURS
[16] LAG TIME-MINUTES

0.21 STORM EVENT SUMMARY
[17] 100% OF LAG-MINUTES
[18] 200% OF LAG-MINUTES
[24] TOTAL PERCOLATION RATE (cfs)
[19] UNIT TIME-MINUTES (100%-200% OF LAG)
3-HOURS 6-HOURS
[6] La-FEET
[7] La-MILES
[8] ELEVATION OF HEADWATER
[9] ELEVATION OF CONCENTRATION POINT
[2] AREA DESIGNATION
[3] AREA - ACRES
[4] L-FEET
[5] L-MILES
5 0.02

1.4 1.4

2.8 21.3

4.61 0.02

PHYSICAL DATA

RAINFALL DATA
[1] CONCENTRATION POINT 1
SUBAREA 4

9.790
620

0.013
470.5
468

0.117

70.00 0.000
[12] S^0.5
[13] L*LCA/S^0.5
[14] AVERAGE MANNINGS 'N'
[10] H-FEET 2.5
[11] S-FEET/MILE
Plate E-2.1

Page 2 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT CALHOUN AT AVENUE 49 - 100 YEAR EVENT CONCENTRATION POINT: 1BY MES R. BAZUA, P.E. DATE 1/17/2025

ADJUSTED LOSS RATE

SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AVERAGE

GROUP NUMBER AREA PERCENT INFILTRATION ADJUSTED

INFILTRATION OF AREA RATE INFILTRATION

RATE IMPERVIOUS RATE
(in/hr) (in/hr) (in/hr)
[Plate C-1] [Plate E-6.1] [Plate E-6.2] [Plate E-6.3]
B 56 0.52 90% 0.10 0.00 0.000 0.0000
B 56 0.52 100% 0.05 2.33 0.238 0.0124
B 56 0.52 20% 0.43 0.00 0.000 0.0000B 56 0.52 40% 0.33 0.00 0.000 0.0000B 56 0.52 50% 0.29 0.00 0.000 0.0000B 56 0.52 65% 0.22 6.56 0.670 0.1446B 56 0.52 80% 0.15 0.00 0.000 0.0000B 56 0.52 75% 0.17 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.90 0.092 0.0478B 56 0.52 0% 0.52 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.00 0.000 0.0000 D 93 0.95 90% 0.18 0.00 0.000 0.0000

0.00 0.000 0.0000

0.00 0.000 0.0000
SUM 9.79 SUM 0.2048
VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY)Fm= 0.102390603C= 0.00190Ft=C(24-(T/60))^1.55 = 0.00190 0.10 in/hr LOW LOSS RATE (80-90 PERCENT) = 90%Where:T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,T=1 1/2 unit time for the second period, etc.

LANDSCAPING

RETENTION BASINS

GOLF COURSE

MOUNTAINOUS
SF - 1 ACRE
SF - 1/2 ACRESF - 1/4 ACRE
MF - COND0MINIUMS

MF - APARTMENTS

MOBILE HOME PARKS
(24-(T/60))^1.55 +

LAND USE

COMMERCIAL

PAVING/HARDSCAPE
Plate E-2.1

Page 3 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 3 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: MES R. BAZUA, DATE 1/17/2025
DRAINAGE AREA-ACRES 9.79
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 1.38
UNIT TIME-PERCENT OF LAG 362.1
TOTAL ADJUSTED STORM RAIN-INCHES 2.12
CONSTANT LOSS RATE-in/hr 0.20
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.21 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 1.3 0.331 0.20 0.30 0.13 1.23 306.00
2 10 0.17 1.3 0.331 0.20 0.30 0.13 1.23 306.00
3 15 0.25 1.1 0.280 0.20 0.25 0.08 0.73 156.57
4 20 0.33 1.5 0.382 0.20 0.34 0.18 1.73 455.43
5 25 0.42 1.5 0.382 0.20 0.34 0.18 1.73 455.43
6 30 0.50 1.8 0.458 0.20 0.41 0.25 2.48 679.59
7 35 0.58 1.5 0.382 0.20 0.34 0.18 1.73 455.43
8 40 0.67 1.8 0.458 0.20 0.41 0.25 2.48 679.59
9 45 0.75 1.8 0.458 0.20 0.41 0.25 2.48 679.59
10 50 0.83 1.5 0.382 0.20 0.34 0.18 1.73 455.43
11 55 0.92 1.6 0.407 0.20 0.37 0.20 1.98 530.15
12 60 1.00 1.8 0.458 0.20 0.41 0.25 2.48 679.59
13 65 1.08 2.2 0.560 0.20 0.50 0.35 3.47 978.46
14 70 1.17 2.2 0.560 0.20 0.50 0.35 3.47 978.46
15 75 1.25 2.2 0.560 0.20 0.50 0.35 3.47 978.46
16 80 1.33 2.0 0.509 0.20 0.46 0.30 2.98 829.02
17 85 1.42 2.6 0.661 0.20 0.60 0.46 4.47 1277.32
18 90 1.50 2.7 0.687 0.20 0.62 0.48 4.72 1352.04
19 95 1.58 2.4 0.611 0.20 0.55 0.41 3.97 1127.89
20 100 1.67 2.7 0.687 0.20 0.62 0.48 4.72 1352.04
21 105 1.75 3.3 0.840 0.20 0.76 0.63 6.21 1800.35
22 110 1.83 3.1 0.789 0.20 0.71 0.58 5.72 1650.91
23 115 1.92 2.9 0.738 0.20 0.66 0.53 5.22 1501.48
24 120 2.00 3.0 0.763 0.20 0.69 0.56 5.47 1576.19
25 125 2.08 3.1 0.789 0.20 0.71 0.58 5.72 1650.91
26 130 2.17 4.2 1.068 0.20 0.96 0.86 8.46 2472.80
27 135 2.25 5.0 1.272 0.20 1.14 1.07 10.45 3070.54
28 140 2.33 3.5 0.890 0.20 0.80 0.69 6.71 1949.78
29 145 2.42 6.8 1.730 0.20 1.56 1.53 14.93 4415.45
30 150 2.50 7.3 1.857 0.20 1.67 1.65 16.18 4789.04
31 155 2.58 8.2 2.086 0.20 1.88 1.88 18.42 5461.49
32 160 2.67 5.9 1.501 0.20 1.35 1.30 12.69 3742.99
33 165 2.75 2.0 0.509 0.20 0.46 0.30 2.98 829.02
34 170 2.83 1.8 0.458 0.20 0.41 0.25 2.48 679.59
35 175 2.92 1.8 0.458 0.20 0.41 0.25 2.48 679.59
36 180 3.00 0.6 0.153 0.20 0.14 0.02 0.15 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.51
FLOOD VOLUME (acft) 1.23
FLOOD VOLUME (cuft) 53707.39
REQUIRED STORAGE (acft) 1.17
REQUIRED STORAGE (cuft) 50982.60
PEAK FLOW RATE (cfs) 18.42
Loss Rate
in/hr
Time

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 4 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 6 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 9.79
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 1.38
UNIT TIME-PERCENT OF LAG 362.1
TOTAL ADJUSTED STORM RAIN-INCHES 2.78
CONSTANT LOSS RATE-in/hr 0.205
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.21 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 0.5 0.167 0.20 0.15 0.02 0.16 0.00
2 10 0.17 0.6 0.200 0.20 0.18 0.02 0.20 0.00
3 15 0.25 0.6 0.200 0.20 0.18 0.02 0.20 0.00
4 20 0.33 0.6 0.200 0.20 0.18 0.02 0.20 0.00
5 25 0.42 0.6 0.200 0.20 0.18 0.02 0.20 0.00
6 30 0.50 0.7 0.234 0.20 0.21 0.03 0.28 20.52
7 35 0.58 0.7 0.234 0.20 0.21 0.03 0.28 20.52
8 40 0.67 0.7 0.234 0.20 0.21 0.03 0.28 20.52
9 45 0.75 0.7 0.234 0.20 0.21 0.03 0.28 20.52
10 50 0.83 0.7 0.234 0.20 0.21 0.03 0.28 20.52
11 55 0.92 0.7 0.234 0.20 0.21 0.03 0.28 20.52
12 60 1.00 0.8 0.267 0.20 0.24 0.06 0.61 118.50
13 65 1.08 0.8 0.267 0.20 0.24 0.06 0.61 118.50
14 70 1.17 0.8 0.267 0.20 0.24 0.06 0.61 118.50
15 75 1.25 0.8 0.267 0.20 0.24 0.06 0.61 118.50
16 80 1.33 0.8 0.267 0.20 0.24 0.06 0.61 118.50
17 85 1.42 0.8 0.267 0.20 0.24 0.06 0.61 118.50
18 90 1.50 0.8 0.267 0.20 0.24 0.06 0.61 118.50
19 95 1.58 0.8 0.267 0.20 0.24 0.06 0.61 118.50
20 100 1.67 0.8 0.267 0.20 0.24 0.06 0.61 118.50
21 105 1.75 0.8 0.267 0.20 0.24 0.06 0.61 118.50
22 110 1.83 0.8 0.267 0.20 0.24 0.06 0.61 118.50
23 115 1.92 0.8 0.267 0.20 0.24 0.06 0.61 118.50
24 120 2.00 0.9 0.300 0.20 0.27 0.10 0.93 216.48
25 125 2.08 0.8 0.267 0.20 0.24 0.06 0.61 118.50
26 130 2.17 0.9 0.300 0.20 0.27 0.10 0.93 216.48
27 135 2.25 0.9 0.300 0.20 0.27 0.10 0.93 216.48
28 140 2.33 0.9 0.300 0.20 0.27 0.10 0.93 216.48
29 145 2.42 0.9 0.300 0.20 0.27 0.10 0.93 216.48
30 150 2.50 0.9 0.300 0.20 0.27 0.10 0.93 216.48
31 155 2.58 0.9 0.300 0.20 0.27 0.10 0.93 216.48
32 160 2.67 0.9 0.300 0.20 0.27 0.10 0.93 216.48
33 165 2.75 1.0 0.334 0.20 0.30 0.13 1.26 314.46
34 170 2.83 1.0 0.334 0.20 0.30 0.13 1.26 314.46
35 175 2.92 1.0 0.334 0.20 0.30 0.13 1.26 314.46
36 180 3.00 1.0 0.334 0.20 0.30 0.13 1.26 314.46
37 185 3.08 1.0 0.334 0.20 0.30 0.13 1.26 314.46
38 190 3.17 1.1 0.367 0.20 0.33 0.16 1.59 412.44
39 195 3.25 1.1 0.367 0.20 0.33 0.16 1.59 412.44
40 200 3.33 1.1 0.367 0.20 0.33 0.16 1.59 412.44
41 205 3.42 1.2 0.400 0.20 0.36 0.20 1.91 510.41
42 210 3.50 1.3 0.434 0.20 0.39 0.23 2.24 608.39
43 215 3.58 1.4 0.467 0.20 0.42 0.26 2.57 706.37
44 220 3.67 1.4 0.467 0.20 0.42 0.26 2.57 706.37
45 225 3.75 1.5 0.500 0.20 0.45 0.30 2.89 804.35
46 230 3.83 1.5 0.500 0.20 0.45 0.30 2.89 804.35
47 235 3.92 1.6 0.534 0.20 0.48 0.33 3.22 902.33
48 240 4.00 1.6 0.534 0.20 0.48 0.33 3.22 902.33
49 245 4.08 1.7 0.567 0.20 0.51 0.36 3.55 1000.31
50 250 4.17 1.8 0.600 0.20 0.54 0.40 3.87 1098.28
51 255 4.25 1.9 0.634 0.20 0.57 0.43 4.20 1196.26
52 260 4.33 2.0 0.667 0.20 0.60 0.46 4.53 1294.24
53 265 4.42 2.1 0.701 0.20 0.63 0.50 4.85 1392.22
54 270 4.50 2.1 0.701 0.20 0.63 0.50 4.85 1392.22
55 275 4.58 2.2 0.734 0.20 0.66 0.53 5.18 1490.20
56 280 4.67 2.3 0.767 0.20 0.69 0.56 5.51 1588.18

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
Plate E-2.2

Page 5 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
57 285 4.75 2.4 0.801 0.20 0.72 0.60 5.83 1686.15
58 290 4.83 2.4 0.801 0.20 0.72 0.60 5.83 1686.15
59 295 4.92 2.5 0.834 0.20 0.75 0.63 6.16 1784.13
60 300 5.00 2.6 0.867 0.20 0.78 0.66 6.49 1882.11
61 305 5.08 3.1 1.034 0.20 0.93 0.83 8.12 2372.00
62 310 5.17 3.6 1.201 0.20 1.08 1.00 9.75 2861.89
63 315 5.25 3.9 1.301 0.20 1.17 1.10 10.73 3155.83
64 320 5.33 4.2 1.401 0.20 1.26 1.20 11.71 3449.76
65 325 5.42 4.7 1.568 0.20 1.41 1.36 13.35 3939.66
66 330 5.50 5.6 1.868 0.20 1.68 1.66 16.28 4821.46
67 335 5.58 1.9 0.634 0.20 0.57 0.43 4.20 1196.26
68 340 5.67 0.9 0.300 0.20 0.27 0.10 0.93 216.48
69 345 5.75 0.6 0.200 0.20 0.18 0.02 0.20 0.00
70 350 5.83 0.5 0.167 0.20 0.15 0.02 0.16 0.00
71 355 5.92 0.3 0.100 0.20 0.09 0.01 0.10 0.00
72 360 6.00 0.2 0.067 0.20 0.06 0.01 0.07 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.59
FLOOD VOLUME (acft) 1.30
FLOOD VOLUME (cuft) 56587.21
REQUIRED STORAGE (acft) 1.19
REQUIRED STORAGE (cuft) 51653.82
PEAK FLOW RATE (cfs) 16.28
Plate E-2.2

Page 6 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 24 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 9.790 CONSTANT LOSS RATE-in/hr n/a
UNIT TIME-MINUTES 15 VARIABLE LOSS RATE (AVG) in/hr 0.2048 LAG TIME - MINUTES 1.38 MINIMUM LOSS RATE (for var. loss) - in/hr 0.102 UNIT TIME-PERCENT OF LAG 1086.4 LOW LOSS RATE - DECIMAL 0.90 TOTAL ADJUSTED STORM RAIN-INCHES 4.47 C 0.00190
PERCOLATION RATE (cfs) 0.21
Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 15 0.25 0.2 0.036 0.362 0.032 0.004 0.04 0.00
2 30 0.50 0.3 0.054 0.357 0.048 0.005 0.05 0.00
3 45 0.75 0.3 0.054 0.353 0.048 0.005 0.05 0.00
4 60 1.00 0.4 0.072 0.349 0.064 0.007 0.07 0.00
5 75 1.25 0.3 0.054 0.345 0.048 0.005 0.05 0.00
6 90 1.50 0.3 0.054 0.341 0.048 0.005 0.05 0.00
7 105 1.75 0.3 0.054 0.337 0.048 0.005 0.05 0.00
8 120 2.00 0.4 0.072 0.333 0.064 0.007 0.07 0.00
9 135 2.25 0.4 0.072 0.329 0.064 0.007 0.07 0.00
10 150 2.50 0.4 0.072 0.325 0.064 0.007 0.07 0.00
11 165 2.75 0.5 0.089 0.321 0.080 0.009 0.09 0.00
12 180 3.00 0.5 0.089 0.317 0.080 0.009 0.09 0.00
13 195 3.25 0.5 0.089 0.313 0.080 0.009 0.09 0.00
14 210 3.50 0.5 0.089 0.309 0.080 0.009 0.09 0.00
15 225 3.75 0.5 0.089 0.305 0.080 0.009 0.09 0.00
16 240 4.00 0.6 0.107 0.301 0.097 0.011 0.11 0.00
17 255 4.25 0.6 0.107 0.297 0.097 0.011 0.11 0.00
18 270 4.50 0.7 0.125 0.294 0.113 0.013 0.12 0.00
19 285 4.75 0.7 0.125 0.290 0.113 0.013 0.12 0.00
20 300 5.00 0.8 0.143 0.286 0.129 0.014 0.14 0.00
21 315 5.25 0.6 0.107 0.282 0.097 0.011 0.11 0.00
22 330 5.50 0.7 0.125 0.279 0.113 0.013 0.12 0.00
23 345 5.75 0.8 0.143 0.275 0.129 0.014 0.14 0.00
24 360 6.00 0.8 0.143 0.272 0.129 0.014 0.14 0.00
25 375 6.25 0.9 0.161 0.268 0.145 0.016 0.16 0.00
26 390 6.50 0.9 0.161 0.264 0.145 0.016 0.16 0.00
27 405 6.75 1.0 0.179 0.261 0.161 0.018 0.18 0.00
28 420 7.00 1.0 0.179 0.257 0.161 0.018 0.18 0.00
29 435 7.25 1.0 0.179 0.254 0.161 0.018 0.18 0.00
30 450 7.50 1.1 0.197 0.250 0.177 0.020 0.19 0.00
31 465 7.75 1.2 0.215 0.247 0.193 0.021 0.21 0.00
32 480 8.00 1.3 0.232 0.243 0.209 0.023 0.23 13.15
33 495 8.25 1.5 0.268 0.240 0.241 0.028 0.28 55.92
34 510 8.50 1.5 0.268 0.237 0.241 0.031 0.31 85.41
35 525 8.75 1.6 0.286 0.233 0.257 0.053 0.52 272.18
36 540 9.00 1.7 0.304 0.230 0.274 0.074 0.72 458.69
37 555 9.25 1.9 0.340 0.227 0.306 0.113 1.10 802.48
38 570 9.50 2.0 0.358 0.224 0.322 0.134 1.31 988.46
39 585 9.75 2.1 0.375 0.220 0.338 0.155 1.52 1174.18
40 600 10.00 2.2 0.393 0.217 0.354 0.176 1.72 1359.63
41 615 10.25 1.5 0.268 0.214 0.241 0.054 0.53 284.49
42 630 10.50 1.5 0.268 0.211 0.241 0.057 0.56 311.86
43 645 10.75 2.0 0.358 0.208 0.322 0.150 1.46 1126.65
44 660 11.00 2.0 0.358 0.205 0.322 0.153 1.49 1153.47
45 675 11.25 1.9 0.340 0.202 0.306 0.138 1.35 1022.46
46 690 11.50 1.9 0.340 0.199 0.306 0.141 1.38 1048.71
47 705 11.75 1.7 0.304 0.196 0.274 0.108 1.06 759.60
48 720 12.00 1.8 0.322 0.193 0.290 0.129 1.26 942.83
49 735 12.25 2.5 0.447 0.190 0.402 0.257 2.51 2071.00
50 750 12.50 2.6 0.465 0.187 0.418 0.278 2.72 2253.64
51 765 12.75 2.8 0.501 0.185 0.451 0.316 3.09 2593.53
52 780 13.00 2.9 0.519 0.182 0.467 0.337 3.30 2775.58
53 795 13.25 3.4 0.608 0.179 0.547 0.429 4.20 3587.49
54 810 13.50 3.4 0.608 0.176 0.547 0.432 4.23 3611.39
55 825 13.75 2.3 0.411 0.174 0.370 0.238 2.33 1902.04
56 840 14.00 2.3 0.411 0.171 0.370 0.240 2.35 1925.32
57 855 14.25 2.7 0.483 0.168 0.434 0.314 3.08 2578.46
58 870 14.50 2.6 0.465 0.166 0.418 0.299 2.93 2443.57
59 885 14.75 2.6 0.465 0.163 0.418 0.302 2.95 2465.90
60 900 15.00 2.5 0.447 0.161 0.402 0.286 2.80 2330.36
61 915 15.25 2.4 0.429 0.158 0.386 0.271 2.65 2194.50
62 930 15.50 2.3 0.411 0.156 0.370 0.255 2.50 2058.30
63 945 15.75 1.9 0.340 0.153 0.306 0.186 1.82 1449.14
64 960 16.00 1.9 0.340 0.151 0.306 0.189 1.85 1469.81
65 975 16.25 0.4 0.072 0.149 0.064 0.007 0.07 0.00
66 990 16.50 0.4 0.072 0.147 0.064 0.007 0.07 0.00
67 1005 16.75 0.3 0.054 0.144 0.048 0.005 0.05 0.00
Time Loss Rate
in/hr

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 7 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
68 1020 17.00 0.3 0.054 0.142 0.048 0.005 0.05 0.00
69 1035 17.25 0.5 0.089 0.140 0.080 0.009 0.09 0.00
70 1050 17.50 0.5 0.089 0.138 0.080 0.009 0.09 0.00
71 1065 17.75 0.5 0.089 0.136 0.080 0.009 0.09 0.00
72 1080 18.00 0.4 0.072 0.134 0.064 0.007 0.07 0.00
73 1095 18.25 0.4 0.072 0.132 0.064 0.007 0.07 0.00
74 1110 18.50 0.4 0.072 0.130 0.064 0.007 0.07 0.00
75 1125 18.75 0.3 0.054 0.128 0.048 0.005 0.05 0.00
76 1140 19.00 0.2 0.036 0.126 0.032 0.004 0.04 0.00
77 1155 19.25 0.3 0.054 0.124 0.048 0.005 0.05 0.00
78 1170 19.50 0.4 0.072 0.123 0.064 0.007 0.07 0.00
79 1185 19.75 0.3 0.054 0.121 0.048 0.005 0.05 0.00
80 1200 20.00 0.2 0.036 0.119 0.032 0.004 0.04 0.00
81 1215 20.25 0.3 0.054 0.118 0.048 0.005 0.05 0.00
82 1230 20.50 0.3 0.054 0.116 0.048 0.005 0.05 0.00
83 1245 20.75 0.3 0.054 0.115 0.048 0.005 0.05 0.00
84 1260 21.00 0.2 0.036 0.113 0.032 0.004 0.04 0.00
85 1275 21.25 0.3 0.054 0.112 0.048 0.005 0.05 0.00
86 1290 21.50 0.2 0.036 0.111 0.032 0.004 0.04 0.00
87 1305 21.75 0.3 0.054 0.110 0.048 0.005 0.05 0.00
88 1320 22.00 0.2 0.036 0.108 0.032 0.004 0.04 0.00
89 1335 22.25 0.3 0.054 0.107 0.048 0.005 0.05 0.00
90 1350 22.50 0.2 0.036 0.106 0.032 0.004 0.04 0.00
91 1365 22.75 0.2 0.036 0.105 0.032 0.004 0.04 0.00
92 1380 23.00 0.2 0.036 0.105 0.032 0.004 0.04 0.00
93 1395 23.25 0.2 0.036 0.104 0.032 0.004 0.04 0.00
94 1410 23.50 0.2 0.036 0.103 0.032 0.004 0.04 0.00
95 1425 23.75 0.2 0.036 0.103 0.032 0.004 0.04 0.00
96 1440 24.00 0.2 0.036 0.102 0.032 0.004 0.04 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.71
FLOOD VOLUME (acft) 1.40
FLOOD VOLUME (cuft) 60935.59
REQUIRED STORAGE (acft) 1.14
REQUIRED STORAGE (cuft) 49570.20
PEAK FLOW (cfs) 4.23
Plate E-2.2

Page 8 of 14 ends

Item 33.

PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB # 0
1 BASIN CHARACTERISTICS

CONTOUR DEPTH AREA VOLUME

INCR TOTAL INCR TOTAL INCR TOTAL
(ft) (ft) (sf) (sf) (cuft) (cuft) (acre-ft)
464.5 0 0 13730 0 0 0.00
465.5 1 1 1470 15200 14465 14465 0.33
466.5 1 2 1500 16700 15950 30415 0.70
467.5 1 3 1570 18270 17485 47900 1.10
468 0.5 3.5 805 19075 9336 57236 1.31

PERCOLATION CALCULATIONS
PERCOLATION RATE 0.67 in/hr 0.21 cfs

MAXWELL IV DRYWELLS
NUMBER USED 0
RATE/DRYWELL 0 cfs
TOTAL DISSIPATED 0 cfs
TOTAL PERCOLATION RATE 0.21 cfs
Basin Characteristics

Page 9 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 3 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 1.23 370 370 64 306 464.52 306 0.01
2 10 1.23 370 676 64 612 464.54 612 0.01
3 15 0.73 220 832 64 769 464.55 769 0.02
4 20 1.73 519 1,288 64 1,224 464.58 1,224 0.03
5 25 1.73 519 1,743 64 1,679 464.62 1,679 0.04
6 30 2.48 743 2,423 64 2,359 464.66 2,359 0.05
7 35 1.73 519 2,878 64 2,814 464.69 2,814 0.06
8 40 2.48 743 3,558 64 3,494 464.74 3,494 0.08
9 45 2.48 743 4,238 64 4,174 464.79 4,174 0.10
10 50 1.73 519 4,693 64 4,629 464.82 4,629 0.11
11 55 1.98 594 5,223 64 5,159 464.86 5,159 0.12
12 60 2.48 743 5,903 64 5,839 464.90 5,839 0.13
13 65 3.47 1,042 6,881 64 6,817 464.97 6,817 0.16
14 70 3.47 1,042 7,860 64 7,796 465.04 7,796 0.18
15 75 3.47 1,042 8,838 64 8,774 465.11 8,774 0.20
16 80 2.98 893 9,667 64 9,603 465.16 9,603 0.22
17 85 4.47 1,341 10,944 64 10,881 465.25 10,881 0.25
18 90 4.72 1,416 12,296 64 12,233 465.35 12,233 0.28
19 95 3.97 1,192 13,424 64 13,360 465.42 13,360 0.31
20 100 4.72 1,416 14,776 64 14,712 465.52 14,712 0.34
21 105 6.21 1,864 16,577 64 16,513 465.63 16,513 0.38
22 110 5.72 1,715 18,228 64 18,164 465.73 18,164 0.42
23 115 5.22 1,565 19,729 64 19,665 465.83 19,665 0.45
24 120 5.47 1,640 21,305 64 21,241 465.92 21,241 0.49
25 125 5.72 1,715 22,956 64 22,892 466.03 22,892 0.53
26 130 8.46 2,537 25,429 64 25,365 466.18 25,365 0.58
27 135 10.45 3,134 28,500 64 28,436 466.38 28,436 0.65
28 140 6.71 2,014 30,449 64 30,385 466.50 30,385 0.70
29 145 14.93 4,479 34,865 64 34,801 466.75 34,801 0.80
30 150 16.18 4,853 39,654 64 39,590 467.02 39,590 0.91
31 155 18.42 5,525 45,115 64 45,051 467.34 45,051 1.03
32 160 12.69 3,807 48,858 64 48,794 467.55 48,794 1.12
33 165 2.98 893 49,687 64 49,623 467.59 49,623 1.14
34 170 2.48 743 50,367 64 50,303 467.63 50,303 1.15
35 175 2.48 743 51,046 64 50,983 467.67 50,983 1.17
36 180 0.15 45 51,027 64 50,964 467.66 50,964 1.17

BALANCE IN
BASIN
TIME
Basin Depth Analysis

Page 10 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.16 49 49 64 - 464.50 - 0.00
2 10 0.20 59 59 64 - 464.50 - 0.00
3 15 0.20 59 59 64 - 464.50 - 0.00
4 20 0.20 59 59 64 - 464.50 - 0.00
5 25 0.20 59 59 64 - 464.50 - 0.00
6 30 0.28 84 84 64 21 464.50 21 0.00
7 35 0.28 84 105 64 41 464.50 41 0.00
8 40 0.28 84 125 64 62 464.50 62 0.00
9 45 0.28 84 146 64 82 464.51 82 0.00
10 50 0.28 84 166 64 103 464.51 103 0.00
11 55 0.28 84 187 64 123 464.51 123 0.00
12 60 0.61 182 306 64 242 464.52 242 0.01
13 65 0.61 182 424 64 360 464.52 360 0.01
14 70 0.61 182 543 64 479 464.53 479 0.01
15 75 0.61 182 661 64 597 464.54 597 0.01
16 80 0.61 182 780 64 716 464.55 716 0.02
17 85 0.61 182 898 64 834 464.56 834 0.02
18 90 0.61 182 1,017 64 953 464.57 953 0.02
19 95 0.61 182 1,135 64 1,071 464.57 1,071 0.02
20 100 0.61 182 1,254 64 1,190 464.58 1,190 0.03
21 105 0.61 182 1,372 64 1,308 464.59 1,308 0.03
22 110 0.61 182 1,491 64 1,427 464.60 1,427 0.03
23 115 0.61 182 1,609 64 1,545 464.61 1,545 0.04
24 120 0.93 280 1,826 64 1,762 464.62 1,762 0.04
25 125 0.61 182 1,944 64 1,880 464.63 1,880 0.04
26 130 0.93 280 2,161 64 2,097 464.64 2,097 0.05
27 135 0.93 280 2,377 64 2,313 464.66 2,313 0.05
28 140 0.93 280 2,593 64 2,530 464.67 2,530 0.06
29 145 0.93 280 2,810 64 2,746 464.69 2,746 0.06
30 150 0.93 280 3,026 64 2,963 464.70 2,963 0.07
31 155 0.93 280 3,243 64 3,179 464.72 3,179 0.07
32 160 0.93 280 3,459 64 3,395 464.73 3,395 0.08
33 165 1.26 378 3,774 64 3,710 464.76 3,710 0.09
34 170 1.26 378 4,088 64 4,024 464.78 4,024 0.09
35 175 1.26 378 4,403 64 4,339 464.80 4,339 0.10
36 180 1.26 378 4,717 64 4,653 464.82 4,653 0.11
37 185 1.26 378 5,032 64 4,968 464.84 4,968 0.11
38 190 1.59 476 5,444 64 5,380 464.87 5,380 0.12
39 195 1.59 476 5,857 64 5,793 464.90 5,793 0.13
40 200 1.59 476 6,269 64 6,205 464.93 6,205 0.14
41 205 1.91 574 6,779 64 6,716 464.96 6,716 0.15
42 210 2.24 672 7,388 64 7,324 465.01 7,324 0.17
43 215 2.57 770 8,094 64 8,030 465.06 8,030 0.18
44 220 2.57 770 8,801 64 8,737 465.10 8,737 0.20
45 225 2.89 868 9,605 64 9,541 465.16 9,541 0.22
46 230 2.89 868 10,409 64 10,345 465.22 10,345 0.24
47 235 3.22 966 11,312 64 11,248 465.28 11,248 0.26
48 240 3.22 966 12,214 64 12,150 465.34 12,150 0.28
49 245 3.55 1,064 13,214 64 13,150 465.41 13,150 0.30
50 250 3.87 1,162 14,312 64 14,249 465.49 14,249 0.33
51 255 4.20 1,260 15,509 64 15,445 465.56 15,445 0.35
52 260 4.53 1,358 16,803 64 16,739 465.64 16,739 0.38
53 265 4.85 1,456 18,195 64 18,131 465.73 18,131 0.42
54 270 4.85 1,456 19,587 64 19,524 465.82 19,524 0.45
55 275 5.18 1,554 21,078 64 21,014 465.91 21,014 0.48

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 11 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
56 280 5.51 1,652 22,666 64 22,602 466.01 22,602 0.52
57 285 5.83 1,750 24,352 64 24,288 466.12 24,288 0.56
58 290 5.83 1,750 26,038 64 25,974 466.22 25,974 0.60
59 295 6.16 1,848 27,822 64 27,758 466.33 27,758 0.64
60 300 6.49 1,946 29,704 64 29,640 466.45 29,640 0.68
61 305 8.12 2,436 32,076 64 32,012 466.59 32,012 0.73
62 310 9.75 2,926 34,938 64 34,874 466.76 34,874 0.80
63 315 10.73 3,220 38,094 64 38,030 466.94 38,030 0.87
64 320 11.71 3,514 41,544 64 41,480 467.13 41,480 0.95
65 325 13.35 4,004 45,483 64 45,420 467.36 45,420 1.04
66 330 16.28 4,885 50,305 64 50,241 467.63 50,241 1.15
67 335 4.20 1,260 51,501 64 51,437 467.69 51,437 1.18
68 340 0.93 280 51,718 64 51,654 467.70 51,654 1.19
69 345 0.20 59 51,713 64 51,649 467.70 51,649 1.19
70 350 0.16 49 51,698 64 51,634 467.70 51,634 1.19
71 355 0.10 29 51,663 64 51,599 467.70 51,599 1.18
72 360 0.07 20 51,619 64 51,555 467.70 51,555 1.18
Basin Depth Analysis

Page 12 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 15 0.04 32 32 192 - 464.50 - 0.00
2 30 0.05 47 47 192 - 464.50 - 0.00
3 45 0.05 47 47 192 - 464.50 - 0.00
4 60 0.07 63 63 192 - 464.50 - 0.00
5 75 0.05 47 47 192 - 464.50 - 0.00
6 90 0.05 47 47 192 - 464.50 - 0.00
7 105 0.05 47 47 192 - 464.50 - 0.00
8 120 0.07 63 63 192 - 464.50 - 0.00
9 135 0.07 63 63 192 - 464.50 - 0.00
10 150 0.07 63 63 192 - 464.50 - 0.00
11 165 0.09 79 79 192 - 464.50 - 0.00
12 180 0.09 79 79 192 - 464.50 - 0.00
13 195 0.09 79 79 192 - 464.50 - 0.00
14 210 0.09 79 79 192 - 464.50 - 0.00
15 225 0.09 79 79 192 - 464.50 - 0.00
16 240 0.11 95 95 192 - 464.50 - 0.00
17 255 0.11 95 95 192 - 464.50 - 0.00
18 270 0.12 110 110 192 - 464.50 - 0.00
19 285 0.12 110 110 192 - 464.50 - 0.00
20 300 0.14 126 126 192 - 464.50 - 0.00
21 315 0.11 95 95 192 - 464.50 - 0.00
22 330 0.12 110 110 192 - 464.50 - 0.00
23 345 0.14 126 126 192 - 464.50 - 0.00
24 360 0.14 126 126 192 - 464.50 - 0.00
25 375 0.16 142 142 192 - 464.50 - 0.00
26 390 0.16 142 142 192 - 464.50 - 0.00
27 405 0.18 158 158 192 - 464.50 - 0.00
28 420 0.18 158 158 192 - 464.50 - 0.00
29 435 0.18 158 158 192 - 464.50 - 0.00
30 450 0.19 173 173 192 - 464.50 - 0.00
31 465 0.21 189 189 192 - 464.50 - 0.00
32 480 0.23 205 205 192 13 464.50 13 0.00
33 495 0.28 248 261 192 69 464.50 69 0.00
34 510 0.31 277 346 192 154 464.51 154 0.00
35 525 0.52 464 618 192 427 464.53 427 0.01
36 540 0.72 650 1,077 192 885 464.56 885 0.02
37 555 1.10 994 1,879 192 1,688 464.62 1,688 0.04
38 570 1.31 1,180 2,868 192 2,676 464.69 2,676 0.06
39 585 1.52 1,366 4,042 192 3,850 464.77 3,850 0.09
40 600 1.72 1,551 5,402 192 5,210 464.86 5,210 0.12
41 615 0.53 476 5,686 192 5,495 464.88 5,495 0.13
42 630 0.56 504 5,998 192 5,806 464.90 5,806 0.13
43 645 1.46 1,318 7,125 192 6,933 464.98 6,933 0.16
44 660 1.49 1,345 8,278 192 8,087 465.06 8,087 0.19
45 675 1.35 1,214 9,301 192 9,109 465.13 9,109 0.21
46 690 1.38 1,240 10,349 192 10,158 465.20 10,158 0.23
47 705 1.06 951 11,109 192 10,917 465.25 10,917 0.25
48 720 1.26 1,134 12,052 192 11,860 465.32 11,860 0.27
49 735 2.51 2,263 14,123 192 13,931 465.46 13,931 0.32
50 750 2.72 2,445 16,376 192 16,185 465.61 16,185 0.37
51 765 3.09 2,785 18,970 192 18,778 465.77 18,778 0.43
52 780 3.30 2,967 21,746 192 21,554 465.94 21,554 0.49
53 795 4.20 3,779 25,333 192 25,141 466.17 25,141 0.58
54 810 4.23 3,803 28,944 192 28,753 466.40 28,753 0.66
55 825 2.33 2,094 30,846 192 30,655 466.51 30,655 0.70
56 840 2.35 2,117 32,772 192 32,580 466.62 32,580 0.75
57 855 3.08 2,770 35,350 192 35,159 466.77 35,159 0.81
58 870 2.93 2,635 37,794 192 37,602 466.91 37,602 0.86

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 13 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
59 885 2.95 2,658 40,260 192 40,068 467.05 40,068 0.92
60 900 2.80 2,522 42,590 192 42,398 467.19 42,398 0.97
61 915 2.65 2,386 44,785 192 44,593 467.31 44,593 1.02
62 930 2.50 2,250 46,843 192 46,651 467.43 46,651 1.07
63 945 1.82 1,641 48,292 192 48,100 467.51 48,100 1.10
64 960 1.85 1,661 49,762 192 49,570 467.59 49,570 1.14
65 975 0.07 63 49,633 192 49,442 467.58 49,442 1.14
66 990 0.07 63 49,505 192 49,313 467.58 49,313 1.13
67 1005 0.05 47 49,360 192 49,169 467.57 49,169 1.13
68 1020 0.05 47 49,216 192 49,024 467.56 49,024 1.13
69 1035 0.09 79 49,103 192 48,911 467.55 48,911 1.12
70 1050 0.09 79 48,990 192 48,798 467.55 48,798 1.12
71 1065 0.09 79 48,877 192 48,686 467.54 48,686 1.12
72 1080 0.07 63 48,749 192 48,557 467.54 48,557 1.11
73 1095 0.07 63 48,620 192 48,428 467.53 48,428 1.11
74 1110 0.07 63 48,491 192 48,300 467.52 48,300 1.11
75 1125 0.05 47 48,347 192 48,155 467.51 48,155 1.11
76 1140 0.04 48,187 32 192 47,995 467.51 47,995 1.10
77 1155 0.05 47 48,042 192 47,851 467.50 47,851 1.10
78 1170 0.07 63 47,914 192 47,722 467.49 47,722 1.10
79 1185 0.05 47 47,769 192 47,578 467.48 47,578 1.09
80 1200 0.04 32 47,609 192 47,418 467.47 47,418 1.09
81 1215 0.05 47 47,465 192 47,273 467.46 47,273 1.09
82 1230 0.05 47 47,320 192 47,129 467.46 47,129 1.08
83 1245 0.05 47 47,176 192 46,984 467.45 46,984 1.08
84 1260 0.04 32 47,016 192 46,824 467.44 46,824 1.07
85 1275 0.05 47 46,872 192 46,680 467.43 46,680 1.07
86 1290 0.04 32 46,711 192 46,520 467.42 46,520 1.07
87 1305 0.05 47 46,567 192 46,375 467.41 46,375 1.06
88 1320 0.04 32 46,407 192 46,215 467.40 46,215 1.06
89 1335 0.05 47 46,262 192 46,071 467.40 46,071 1.06
90 1350 0.04 32 46,102 192 45,911 467.39 45,911 1.05
91 1365 0.04 32 45,942 192 45,751 467.38 45,751 1.05
92 1380 0.04 32 45,782 192 45,590 467.37 45,590 1.05
93 1395 0.04 32 45,622 192 45,430 467.36 45,430 1.04
94 1410 0.04 32 45,462 192 45,270 467.35 45,270 1.04
95 1425 0.04 32 45,302 192 45,110 467.34 45,110 1.04
96 1440 0.04 32 45,142 192 44,950 467.33 44,950 1.03
Basin Depth Analysis

Page 14 of 14 ends

Item 33.
1 2
3 4
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15 16
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21 22
23 24
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31 32
33 34
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37 38
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47 48
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AB C D

RCFCD SYNTHETIC UNIT HYDROGRAPH

DATA INPUT SHEET
WORKSHEET PREPARED BY: JAMES R. BAZUA, P.E.

PROJECT NAME CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB #
CONCENTRATION POINT DESIGNATION 1
AREA DESIGNATION SUBAREA 5

TRIBUTARY AREAS ACRES

COMMERCIAL
PAVING/HARDSCAPE 1.95
SF - 1 ACRE
SF - 1/2 ACRE
SF - 1/4 ACRE
MF - CONDOMINIUMS 4.71

MF - APARTMENTS

MOBILE HOME PARK
LANDSCAPING 2.83

RETENTION BASIN

GOLF COURSE

MOUNTAINOUS
LOW LOSS RATE (PERCENT) 90%
LENGTH OF WATERCOURSE (L) 950
LENGTH TO POINT OPPOSITE CENTROID (Lca) 310
ELEVATION OF HEADWATER 471
ELEVATION OF CONCENTRATION POINT 467
AVERAGE MANNINGS 'N' VALUE 0.02
STORM FREQUENCY (YEAR) 100

POINT RAIN
3-HOUR 2.12
6-HOUR 2.78
24-HOUR 4.47
BASIN CHARACTERISTICS: ELEVATION AREA
463.5 17610
464.5 19400
465.5 21240
466.5 23140
467 24110
PERCOLATION RATE (in/hr) 0.67

DRYWELL DATA

NUMBER USED
PERCOLATION RATE (cfs)

Page 1283 ends

Item 33.

POINT AREA AVERAGE POINT AREA AVERAGE POINT AREA AVERAGE

RAIN POINT RAIN POINT RAIN POINT

INCHES RAIN INCHES RAIN INCHES RAIN
(Plate E-5.2) INCHES (Plate E-5.4) INCHES (Plate E-5.6) INCHES

2.12 9.490 1.00 2.12 2.78 9.490 1.00 2.78 4.47 9.490 1.00 4.47

0.00 0.00 0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00
SUM [5] 9.49 SUM [7] 2.12 SUM [9] 9.49 SUM [11] 2.78 SUM [13] 9.49 SUM [15] 4.47 [16] AREA ADJ FACTOR 1.000 1.000 1.000
[17] ADJ AVG POINT RAIN 2.12 2.78 4.47
DURATION 3-HOUR 6-HOUR 24-HOUR
EFFECTIVE RAIN (in) 1.31 1.30 1.28
FLOOD VOLUME (cu-ft) 45,222 44,840 44,164
(acre-ft) 1.04 1.03 1.01
REQUIRED STORAGE (cu-ft) 41,999 39,086 31,405
(acre-ft) 0.96 0.90 0.72
PEAK FLOW (cfs) 17.21 15.14 3.54
MAXIMUM WSEL (ft) 465.64 465.51 465.13

0.180
310.00

0.002
[12] S^0.5
[13] L*LCA/S^0.5
[14] AVERAGE MANNINGS 'N'
[10] H-FEET 4
[11] S-FEET/MILE

PHYSICAL DATA

RAINFALL DATA
[1] CONCENTRATION POINT 1
SUBAREA 5

9.490
950

0.059
471
467

0.05 2.8

2.8 5.7

22.2 4.72

0.27 STORM EVENT SUMMARY
[17] 100% OF LAG-MINUTES
[18] 200% OF LAG-MINUTES
[24] TOTAL PERCOLATION RATE (cfs)
[19] UNIT TIME-MINUTES (100%-200% OF LAG)
3-HOURS
Plate E-2.1

Page 2 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT CALHOUN AT AVENUE 49 - 100 YEAR EVENT CONCENTRATION POINT: 1BY MES R. BAZUA, P.E. DATE 1/17/2025

ADJUSTED LOSS RATE

SOIL RI PERVIOUS DECIMAL ADJUSTED AREA AVERAGE

GROUP NUMBER AREA PERCENT INFILTRATION ADJUSTED

INFILTRATION OF AREA RATE INFILTRATION

RATE IMPERVIOUS RATE
(in/hr) (in/hr) (in/hr)
[Plate C-1] [Plate E-6.1] [Plate E-6.2] [Plate E-6.3]
B 56 0.52 90% 0.10 0.00 0.000 0.0000
B 56 0.52 100% 0.05 1.95 0.205 0.0107
B 56 0.52 20% 0.43 0.00 0.000 0.0000B 56 0.52 40% 0.33 0.00 0.000 0.0000B 56 0.52 50% 0.29 0.00 0.000 0.0000B 56 0.52 65% 0.22 4.71 0.496 0.1071B 56 0.52 80% 0.15 0.00 0.000 0.0000B 56 0.52 75% 0.17 0.00 0.000 0.0000B 56 0.52 0% 0.52 2.83 0.298 0.1551B 56 0.52 0% 0.52 0.00 0.000 0.0000B 56 0.52 0% 0.52 0.00 0.000 0.0000 D 93 0.95 90% 0.18 0.00 0.000 0.0000

0.00 0.000 0.0000

0.00 0.000 0.0000
SUM 9.49 SUM 0.2729
VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY)Fm= 0.136428767C= 0.00253Ft=C(24-(T/60))^1.55 = 0.00253 0.14 in/hr LOW LOSS RATE (80-90 PERCENT) = 90%Where:T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,T=1 1/2 unit time for the second period, etc. (24-(T/60))^1.55 +

LAND USE

COMMERCIAL

PAVING/HARDSCAPE
SF - 1 ACRE
SF - 1/2 ACRESF - 1/4 ACRE
MF - COND0MINIUMS

MF - APARTMENTS

MOBILE HOME PARKS

LANDSCAPING

RETENTION BASINS

GOLF COURSE

MOUNTAINOUS
Plate E-2.1

Page 3 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 3 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: MES R. BAZUA, DATE 1/17/2025
DRAINAGE AREA-ACRES 9.49
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 2.83
UNIT TIME-PERCENT OF LAG 176.4
TOTAL ADJUSTED STORM RAIN-INCHES 2.12
CONSTANT LOSS RATE-in/hr 0.27
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.27 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 1.3 0.331 0.27 0.30 0.06 0.55 82.80
2 10 0.17 1.3 0.331 0.27 0.30 0.06 0.55 82.80
3 15 0.25 1.1 0.280 0.27 0.25 0.01 0.07 0.00
4 20 0.33 1.5 0.382 0.27 0.34 0.11 1.03 227.65
5 25 0.42 1.5 0.382 0.27 0.34 0.11 1.03 227.65
6 30 0.50 1.8 0.458 0.27 0.41 0.19 1.76 444.94
7 35 0.58 1.5 0.382 0.27 0.34 0.11 1.03 227.65
8 40 0.67 1.8 0.458 0.27 0.41 0.19 1.76 444.94
9 45 0.75 1.8 0.458 0.27 0.41 0.19 1.76 444.94
10 50 0.83 1.5 0.382 0.27 0.34 0.11 1.03 227.65
11 55 0.92 1.6 0.407 0.27 0.37 0.13 1.27 300.08
12 60 1.00 1.8 0.458 0.27 0.41 0.19 1.76 444.94
13 65 1.08 2.2 0.560 0.27 0.50 0.29 2.72 734.65
14 70 1.17 2.2 0.560 0.27 0.50 0.29 2.72 734.65
15 75 1.25 2.2 0.560 0.27 0.50 0.29 2.72 734.65
16 80 1.33 2.0 0.509 0.27 0.46 0.24 2.24 589.79
17 85 1.42 2.6 0.661 0.27 0.60 0.39 3.69 1024.36
18 90 1.50 2.7 0.687 0.27 0.62 0.41 3.93 1096.79
19 95 1.58 2.4 0.611 0.27 0.55 0.34 3.20 879.50
20 100 1.67 2.7 0.687 0.27 0.62 0.41 3.93 1096.79
21 105 1.75 3.3 0.840 0.27 0.76 0.57 5.38 1531.35
22 110 1.83 3.1 0.789 0.27 0.71 0.52 4.89 1386.50
23 115 1.92 2.9 0.738 0.27 0.66 0.46 4.41 1241.64
24 120 2.00 3.0 0.763 0.27 0.69 0.49 4.65 1314.07
25 125 2.08 3.1 0.789 0.27 0.71 0.52 4.89 1386.50
26 130 2.17 4.2 1.068 0.27 0.96 0.80 7.55 2183.20
27 135 2.25 5.0 1.272 0.27 1.14 1.00 9.48 2762.62
28 140 2.33 3.5 0.890 0.27 0.80 0.62 5.86 1676.21
29 145 2.42 6.8 1.730 0.27 1.56 1.46 13.83 4066.32
30 150 2.50 7.3 1.857 0.27 1.67 1.58 15.03 4428.46
31 155 2.58 8.2 2.086 0.27 1.88 1.81 17.21 5080.31
32 160 2.67 5.9 1.501 0.27 1.35 1.23 11.65 3414.47
33 165 2.75 2.0 0.509 0.27 0.46 0.24 2.24 589.79
34 170 2.83 1.8 0.458 0.27 0.41 0.19 1.76 444.94
35 175 2.92 1.8 0.458 0.27 0.41 0.19 1.76 444.94
36 180 3.00 0.6 0.153 0.27 0.14 0.02 0.14 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.31
FLOOD VOLUME (acft) 1.04
FLOOD VOLUME (cuft) 45221.59
REQUIRED STORAGE (acft) 0.96
REQUIRED STORAGE (cuft) 41998.54
PEAK FLOW RATE (cfs) 17.21
Loss Rate
in/hr
Time

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 4 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 6 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 9.49
UNIT TIME-MINUTES 5
LAG TIME - MINUTES 2.83
UNIT TIME-PERCENT OF LAG 176.4
TOTAL ADJUSTED STORM RAIN-INCHES 2.78
CONSTANT LOSS RATE-in/hr 0.273
LOW LOSS RATE - PERCENT 90% TOTAL PERCOLATION RATE (cfs) 0.27 cfs Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 5 0.08 0.5 0.167 0.27 0.15 0.02 0.16 0.00
2 10 0.17 0.6 0.200 0.27 0.18 0.02 0.19 0.00
3 15 0.25 0.6 0.200 0.27 0.18 0.02 0.19 0.00
4 20 0.33 0.6 0.200 0.27 0.18 0.02 0.19 0.00
5 25 0.42 0.6 0.200 0.27 0.18 0.02 0.19 0.00
6 30 0.50 0.7 0.234 0.27 0.21 0.02 0.22 0.00
7 35 0.58 0.7 0.234 0.27 0.21 0.02 0.22 0.00
8 40 0.67 0.7 0.234 0.27 0.21 0.02 0.22 0.00
9 45 0.75 0.7 0.234 0.27 0.21 0.02 0.22 0.00
10 50 0.83 0.7 0.234 0.27 0.21 0.02 0.22 0.00
11 55 0.92 0.7 0.234 0.27 0.21 0.02 0.22 0.00
12 60 1.00 0.8 0.267 0.27 0.24 0.03 0.25 0.00
13 65 1.08 0.8 0.267 0.27 0.24 0.03 0.25 0.00
14 70 1.17 0.8 0.267 0.27 0.24 0.03 0.25 0.00
15 75 1.25 0.8 0.267 0.27 0.24 0.03 0.25 0.00
16 80 1.33 0.8 0.267 0.27 0.24 0.03 0.25 0.00
17 85 1.42 0.8 0.267 0.27 0.24 0.03 0.25 0.00
18 90 1.50 0.8 0.267 0.27 0.24 0.03 0.25 0.00
19 95 1.58 0.8 0.267 0.27 0.24 0.03 0.25 0.00
20 100 1.67 0.8 0.267 0.27 0.24 0.03 0.25 0.00
21 105 1.75 0.8 0.267 0.27 0.24 0.03 0.25 0.00
22 110 1.83 0.8 0.267 0.27 0.24 0.03 0.25 0.00
23 115 1.92 0.8 0.267 0.27 0.24 0.03 0.25 0.00
24 120 2.00 0.9 0.300 0.27 0.27 0.03 0.26 0.00
25 125 2.08 0.8 0.267 0.27 0.24 0.03 0.25 0.00
26 130 2.17 0.9 0.300 0.27 0.27 0.03 0.26 0.00
27 135 2.25 0.9 0.300 0.27 0.27 0.03 0.26 0.00
28 140 2.33 0.9 0.300 0.27 0.27 0.03 0.26 0.00
29 145 2.42 0.9 0.300 0.27 0.27 0.03 0.26 0.00
30 150 2.50 0.9 0.300 0.27 0.27 0.03 0.26 0.00
31 155 2.58 0.9 0.300 0.27 0.27 0.03 0.26 0.00
32 160 2.67 0.9 0.300 0.27 0.27 0.03 0.26 0.00
33 165 2.75 1.0 0.334 0.27 0.30 0.06 0.58 91.00
34 170 2.83 1.0 0.334 0.27 0.30 0.06 0.58 91.00
35 175 2.92 1.0 0.334 0.27 0.30 0.06 0.58 91.00
36 180 3.00 1.0 0.334 0.27 0.30 0.06 0.58 91.00
37 185 3.08 1.0 0.334 0.27 0.30 0.06 0.58 91.00
38 190 3.17 1.1 0.367 0.27 0.33 0.09 0.89 185.97
39 195 3.25 1.1 0.367 0.27 0.33 0.09 0.89 185.97
40 200 3.33 1.1 0.367 0.27 0.33 0.09 0.89 185.97
41 205 3.42 1.2 0.400 0.27 0.36 0.13 1.21 280.95
42 210 3.50 1.3 0.434 0.27 0.39 0.16 1.53 375.93
43 215 3.58 1.4 0.467 0.27 0.42 0.19 1.84 470.90
44 220 3.67 1.4 0.467 0.27 0.42 0.19 1.84 470.90
45 225 3.75 1.5 0.500 0.27 0.45 0.23 2.16 565.88
46 230 3.83 1.5 0.500 0.27 0.45 0.23 2.16 565.88
47 235 3.92 1.6 0.534 0.27 0.48 0.26 2.48 660.85
48 240 4.00 1.6 0.534 0.27 0.48 0.26 2.48 660.85
49 245 4.08 1.7 0.567 0.27 0.51 0.29 2.79 755.83
50 250 4.17 1.8 0.600 0.27 0.54 0.33 3.11 850.81
51 255 4.25 1.9 0.634 0.27 0.57 0.36 3.43 945.78
52 260 4.33 2.0 0.667 0.27 0.60 0.39 3.74 1040.76
53 265 4.42 2.1 0.701 0.27 0.63 0.43 4.06 1135.73
54 270 4.50 2.1 0.701 0.27 0.63 0.43 4.06 1135.73
55 275 4.58 2.2 0.734 0.27 0.66 0.46 4.38 1230.71
56 280 4.67 2.3 0.767 0.27 0.69 0.49 4.69 1325.69

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
Plate E-2.2

Page 5 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
Time Loss Rate
in/hr
57 285 4.75 2.4 0.801 0.27 0.72 0.53 5.01 1420.66
58 290 4.83 2.4 0.801 0.27 0.72 0.53 5.01 1420.66
59 295 4.92 2.5 0.834 0.27 0.75 0.56 5.33 1515.64
60 300 5.00 2.6 0.867 0.27 0.78 0.59 5.64 1610.61
61 305 5.08 3.1 1.034 0.27 0.93 0.76 7.22 2085.49
62 310 5.17 3.6 1.201 0.27 1.08 0.93 8.81 2560.37
63 315 5.25 3.9 1.301 0.27 1.17 1.03 9.76 2845.30
64 320 5.33 4.2 1.401 0.27 1.26 1.13 10.71 3130.23
65 325 5.42 4.7 1.568 0.27 1.41 1.30 12.29 3605.11
66 330 5.50 5.6 1.868 0.27 1.68 1.60 15.14 4459.89
67 335 5.58 1.9 0.634 0.27 0.57 0.36 3.43 945.78
68 340 5.67 0.9 0.300 0.27 0.27 0.03 0.26 0.00
69 345 5.75 0.6 0.200 0.27 0.18 0.02 0.19 0.00
70 350 5.83 0.5 0.167 0.27 0.15 0.02 0.16 0.00
71 355 5.92 0.3 0.100 0.27 0.09 0.01 0.09 0.00
72 360 6.00 0.2 0.067 0.27 0.06 0.01 0.06 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.30
FLOOD VOLUME (acft) 1.03
FLOOD VOLUME (cuft) 44839.99
REQUIRED STORAGE (acft) 0.90
REQUIRED STORAGE (cuft) 39085.84
PEAK FLOW RATE (cfs) 15.14
Plate E-2.2

Page 6 of 14 ends

Item 33.

RCFCD SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT 100 YEAR - 24 HOUR STORM EVENT CONCENTRATION POINT: 1
BY: JAMES R. BAZ DATE: 1/17/2025
DRAINAGE AREA-ACRES 9.490 CONSTANT LOSS RATE-in/hr n/a
UNIT TIME-MINUTES 15 VARIABLE LOSS RATE (AVG) in/hr 0.2729 LAG TIME - MINUTES 2.83 MINIMUM LOSS RATE (for var. loss) - in/hr 0.136 UNIT TIME-PERCENT OF LAG 529.1 LOW LOSS RATE - DECIMAL 0.90 TOTAL ADJUSTED STORM RAIN-INCHES 4.47 C 0.00253
PERCOLATION RATE (cfs) 0.27
Unit Time Pattern Storm Effective Flood Required
Period Minutes Hours Percent Rain Rain Hydrograph Storage in/hr Flow
(Plate E-5.9) Max Low in/hr cfs cf
1 15 0.25 0.2 0.036 0.482 0.032 0.004 0.03 0.00
2 30 0.50 0.3 0.054 0.476 0.048 0.005 0.05 0.00
3 45 0.75 0.3 0.054 0.471 0.048 0.005 0.05 0.00
4 60 1.00 0.4 0.072 0.465 0.064 0.007 0.07 0.00
5 75 1.25 0.3 0.054 0.460 0.048 0.005 0.05 0.00
6 90 1.50 0.3 0.054 0.454 0.048 0.005 0.05 0.00
7 105 1.75 0.3 0.054 0.449 0.048 0.005 0.05 0.00
8 120 2.00 0.4 0.072 0.443 0.064 0.007 0.07 0.00
9 135 2.25 0.4 0.072 0.438 0.064 0.007 0.07 0.00
10 150 2.50 0.4 0.072 0.433 0.064 0.007 0.07 0.00
11 165 2.75 0.5 0.089 0.427 0.080 0.009 0.08 0.00
12 180 3.00 0.5 0.089 0.422 0.080 0.009 0.08 0.00
13 195 3.25 0.5 0.089 0.417 0.080 0.009 0.08 0.00
14 210 3.50 0.5 0.089 0.412 0.080 0.009 0.08 0.00
15 225 3.75 0.5 0.089 0.407 0.080 0.009 0.08 0.00
16 240 4.00 0.6 0.107 0.401 0.097 0.011 0.10 0.00
17 255 4.25 0.6 0.107 0.396 0.097 0.011 0.10 0.00
18 270 4.50 0.7 0.125 0.391 0.113 0.013 0.12 0.00
19 285 4.75 0.7 0.125 0.386 0.113 0.013 0.12 0.00
20 300 5.00 0.8 0.143 0.381 0.129 0.014 0.14 0.00
21 315 5.25 0.6 0.107 0.376 0.097 0.011 0.10 0.00
22 330 5.50 0.7 0.125 0.371 0.113 0.013 0.12 0.00
23 345 5.75 0.8 0.143 0.367 0.129 0.014 0.14 0.00
24 360 6.00 0.8 0.143 0.362 0.129 0.014 0.14 0.00
25 375 6.25 0.9 0.161 0.357 0.145 0.016 0.15 0.00
26 390 6.50 0.9 0.161 0.352 0.145 0.016 0.15 0.00
27 405 6.75 1.0 0.179 0.347 0.161 0.018 0.17 0.00
28 420 7.00 1.0 0.179 0.343 0.161 0.018 0.17 0.00
29 435 7.25 1.0 0.179 0.338 0.161 0.018 0.17 0.00
30 450 7.50 1.1 0.197 0.334 0.177 0.020 0.19 0.00
31 465 7.75 1.2 0.215 0.329 0.193 0.021 0.20 0.00
32 480 8.00 1.3 0.232 0.324 0.209 0.023 0.22 0.00
33 495 8.25 1.5 0.268 0.320 0.241 0.027 0.25 0.00
34 510 8.50 1.5 0.268 0.315 0.241 0.027 0.25 0.00
35 525 8.75 1.6 0.286 0.311 0.257 0.029 0.27 0.00
36 540 9.00 1.7 0.304 0.307 0.274 0.030 0.29 13.81
37 555 9.25 1.9 0.340 0.302 0.306 0.037 0.35 73.64
38 570 9.50 2.0 0.358 0.298 0.322 0.060 0.57 263.09
39 585 9.75 2.1 0.375 0.294 0.338 0.082 0.78 452.20
40 600 10.00 2.2 0.393 0.290 0.354 0.104 0.99 640.96
41 615 10.25 1.5 0.268 0.285 0.241 0.027 0.25 0.00
42 630 10.50 1.5 0.268 0.281 0.241 0.027 0.25 0.00
43 645 10.75 2.0 0.358 0.277 0.322 0.080 0.76 441.57
44 660 11.00 2.0 0.358 0.273 0.322 0.085 0.80 476.21
45 675 11.25 1.9 0.340 0.269 0.306 0.071 0.67 357.77
46 690 11.50 1.9 0.340 0.265 0.306 0.075 0.71 391.68
47 705 11.75 1.7 0.304 0.261 0.274 0.043 0.41 119.79
48 720 12.00 1.8 0.322 0.257 0.290 0.065 0.61 305.68
49 735 12.25 2.5 0.447 0.253 0.402 0.194 1.84 1407.47
50 750 12.50 2.6 0.465 0.250 0.418 0.215 2.04 1592.60
51 765 12.75 2.8 0.501 0.246 0.451 0.255 2.42 1930.06
52 780 13.00 2.9 0.519 0.242 0.467 0.276 2.62 2114.43
53 795 13.25 3.4 0.608 0.239 0.547 0.369 3.51 2909.26
54 810 13.50 3.4 0.608 0.235 0.547 0.373 3.54 2940.13
55 825 13.75 2.3 0.411 0.231 0.370 0.180 1.71 1290.76
56 840 14.00 2.3 0.411 0.228 0.370 0.183 1.74 1320.84
57 855 14.25 2.7 0.483 0.224 0.434 0.258 2.45 1961.36
58 870 14.50 2.6 0.465 0.221 0.418 0.244 2.32 1837.90
59 885 14.75 2.6 0.465 0.218 0.418 0.247 2.35 1866.75
60 900 15.00 2.5 0.447 0.214 0.402 0.233 2.21 1742.46
61 915 15.25 2.4 0.429 0.211 0.386 0.218 2.07 1617.74
62 930 15.50 2.3 0.411 0.208 0.370 0.204 1.93 1492.59
63 945 15.75 1.9 0.340 0.205 0.306 0.135 1.28 908.87
64 960 16.00 1.9 0.340 0.201 0.306 0.138 1.31 935.56
65 975 16.25 0.4 0.072 0.198 0.064 0.007 0.07 0.00
66 990 16.50 0.4 0.072 0.195 0.064 0.007 0.07 0.00
67 1005 16.75 0.3 0.054 0.192 0.048 0.005 0.05 0.00
Time Loss Rate
in/hr

EFFECTIVE RAIN CALCULATION FORM
Plate E-2.2

Page 7 of 14 ends

Item 33.

EFFECTIVE RAIN CALCULATION FORM
68 1020 17.00 0.3 0.054 0.189 0.048 0.005 0.05 0.00
69 1035 17.25 0.5 0.089 0.187 0.080 0.009 0.08 0.00
70 1050 17.50 0.5 0.089 0.184 0.080 0.009 0.08 0.00
71 1065 17.75 0.5 0.089 0.181 0.080 0.009 0.08 0.00
72 1080 18.00 0.4 0.072 0.178 0.064 0.007 0.07 0.00
73 1095 18.25 0.4 0.072 0.176 0.064 0.007 0.07 0.00
74 1110 18.50 0.4 0.072 0.173 0.064 0.007 0.07 0.00
75 1125 18.75 0.3 0.054 0.171 0.048 0.005 0.05 0.00
76 1140 19.00 0.2 0.036 0.168 0.032 0.004 0.03 0.00
77 1155 19.25 0.3 0.054 0.166 0.048 0.005 0.05 0.00
78 1170 19.50 0.4 0.072 0.164 0.064 0.007 0.07 0.00
79 1185 19.75 0.3 0.054 0.161 0.048 0.005 0.05 0.00
80 1200 20.00 0.2 0.036 0.159 0.032 0.004 0.03 0.00
81 1215 20.25 0.3 0.054 0.157 0.048 0.005 0.05 0.00
82 1230 20.50 0.3 0.054 0.155 0.048 0.005 0.05 0.00
83 1245 20.75 0.3 0.054 0.153 0.048 0.005 0.05 0.00
84 1260 21.00 0.2 0.036 0.151 0.032 0.004 0.03 0.00
85 1275 21.25 0.3 0.054 0.149 0.048 0.005 0.05 0.00
86 1290 21.50 0.2 0.036 0.148 0.032 0.004 0.03 0.00
87 1305 21.75 0.3 0.054 0.146 0.048 0.005 0.05 0.00
88 1320 22.00 0.2 0.036 0.145 0.032 0.004 0.03 0.00
89 1335 22.25 0.3 0.054 0.143 0.048 0.005 0.05 0.00
90 1350 22.50 0.2 0.036 0.142 0.032 0.004 0.03 0.00
91 1365 22.75 0.2 0.036 0.141 0.032 0.004 0.03 0.00
92 1380 23.00 0.2 0.036 0.139 0.032 0.004 0.03 0.00
93 1395 23.25 0.2 0.036 0.138 0.032 0.004 0.03 0.00
94 1410 23.50 0.2 0.036 0.138 0.032 0.004 0.03 0.00
95 1425 23.75 0.2 0.036 0.137 0.032 0.004 0.03 0.00
96 1440 24.00 0.2 0.036 0.137 0.032 0.004 0.03 0.00

EFFECTIVE RAIN & FLOOD VOLUMES SUMMARY
EFFECTIVE RAIN (in) 1.28
FLOOD VOLUME (acft) 1.01
FLOOD VOLUME (cuft) 44164.39
REQUIRED STORAGE (acft) 0.72
REQUIRED STORAGE (cuft) 31405.17
PEAK FLOW (cfs) 3.54
Plate E-2.2

Page 8 of 14 ends

Item 33.

PROJECT: CALHOUN AT AVENUE 49 - 100 YEAR EVENT
JOB # 0
1 BASIN CHARACTERISTICS

CONTOUR DEPTH AREA VOLUME

INCR TOTAL INCR TOTAL INCR TOTAL
(ft) (ft) (sf) (sf) (cuft) (cuft) (acre-ft)
463.5 0 0 17610 0 0 0.00
464.5 1 1 1790 19400 18505 18505 0.42
465.5 1 2 1840 21240 20320 38825 0.89
466.5 1 3 1900 23140 22190 61015 1.40
467 0.5 3.5 970 24110 11813 72828 1.67

PERCOLATION CALCULATIONS
PERCOLATION RATE 0.67 in/hr 0.27 cfs

MAXWELL IV DRYWELLS
NUMBER USED 0
RATE/DRYWELL 0 cfs
TOTAL DISSIPATED 0 cfs
TOTAL PERCOLATION RATE 0.27 cfs
Basin Characteristics

Page 9 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 3 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.55 165 165 82 83 463.50 83 0.00
2 10 0.55 165 248 82 166 463.51 166 0.00
3 15 0.07 20 185 82 104 463.51 104 0.00
4 20 1.03 310 413 82 331 463.52 331 0.01
5 25 1.03 310 641 82 559 463.53 559 0.01
6 30 1.76 527 1,086 82 1,004 463.55 1,004 0.02
7 35 1.03 310 1,313 82 1,231 463.57 1,231 0.03
8 40 1.76 527 1,758 82 1,676 463.59 1,676 0.04
9 45 1.76 527 2,203 82 2,121 463.61 2,121 0.05
10 50 1.03 310 2,431 82 2,349 463.63 2,349 0.05
11 55 1.27 382 2,731 82 2,649 463.64 2,649 0.06
12 60 1.76 527 3,176 82 3,094 463.67 3,094 0.07
13 65 2.72 817 3,911 82 3,829 463.71 3,829 0.09
14 70 2.72 817 4,645 82 4,563 463.75 4,563 0.10
15 75 2.72 817 5,380 82 5,298 463.79 5,298 0.12
16 80 2.24 672 5,970 82 5,888 463.82 5,888 0.14
17 85 3.69 1,106 6,994 82 6,912 463.87 6,912 0.16
18 90 3.93 1,179 8,091 82 8,009 463.93 8,009 0.18
19 95 3.20 961 8,970 82 8,888 463.98 8,888 0.20
20 100 3.93 1,179 10,067 82 9,985 464.04 9,985 0.23
21 105 5.38 1,613 11,598 82 11,517 464.12 11,517 0.26
22 110 4.89 1,468 12,985 82 12,903 464.20 12,903 0.30
23 115 4.41 1,324 14,227 82 14,145 464.26 14,145 0.32
24 120 4.65 1,396 15,541 82 15,459 464.34 15,459 0.35
25 125 4.89 1,468 16,927 82 16,845 464.41 16,845 0.39
26 130 7.55 2,265 19,110 82 19,028 464.53 19,028 0.44
27 135 9.48 2,845 21,873 82 21,791 464.66 21,791 0.50
28 140 5.86 1,758 23,549 82 23,467 464.74 23,467 0.54
29 145 13.83 4,148 27,616 82 27,534 464.94 27,534 0.63
30 150 15.03 4,510 32,044 82 31,962 465.16 31,962 0.73
31 155 17.21 5,162 37,124 82 37,042 465.41 37,042 0.85
32 160 11.65 3,496 40,539 82 40,457 465.57 40,457 0.93
33 165 2.24 672 41,129 82 41,047 465.60 41,047 0.94
34 170 1.76 527 41,573 82 41,492 465.62 41,492 0.95
35 175 1.76 527 42,018 82 41,936 465.64 41,936 0.96
36 180 0.14 43 41,980 82 41,898 465.64 41,898 0.96

BALANCE IN
BASIN
TIME
Basin Depth Analysis

Page 10 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 5 0.16 47 47 82 - 463.50 - 0.00
2 10 0.19 57 57 82 - 463.50 - 0.00
3 15 0.19 57 57 82 - 463.50 - 0.00
4 20 0.19 57 57 82 - 463.50 - 0.00
5 25 0.19 57 57 82 - 463.50 - 0.00
6 30 0.22 66 66 82 - 463.50 - 0.00
7 35 0.22 66 66 82 - 463.50 - 0.00
8 40 0.22 66 66 82 - 463.50 - 0.00
9 45 0.22 66 66 82 - 463.50 - 0.00
10 50 0.22 66 66 82 - 463.50 - 0.00
11 55 0.22 66 66 82 - 463.50 - 0.00
12 60 0.25 76 76 82 - 463.50 - 0.00
13 65 0.25 76 76 82 - 463.50 - 0.00
14 70 0.25 76 76 82 - 463.50 - 0.00
15 75 0.25 76 76 82 - 463.50 - 0.00
16 80 0.25 76 76 82 - 463.50 - 0.00
17 85 0.25 76 76 82 - 463.50 - 0.00
18 90 0.25 76 76 82 - 463.50 - 0.00
19 95 0.25 76 76 82 - 463.50 - 0.00
20 100 0.25 76 76 82 - 463.50 - 0.00
21 105 0.25 76 76 82 - 463.50 - 0.00
22 110 0.25 76 76 82 - 463.50 - 0.00
23 115 0.25 76 76 82 - 463.50 - 0.00
24 120 0.26 78 78 82 - 463.50 - 0.00
25 125 0.25 76 76 82 - 463.50 - 0.00
26 130 0.26 78 78 82 - 463.50 - 0.00
27 135 0.26 78 78 82 - 463.50 - 0.00
28 140 0.26 78 78 82 - 463.50 - 0.00
29 145 0.26 78 78 82 - 463.50 - 0.00
30 150 0.26 78 78 82 - 463.50 - 0.00
31 155 0.26 78 78 82 - 463.50 - 0.00
32 160 0.26 78 78 82 - 463.50 - 0.00
33 165 0.58 173 173 82 91 463.50 91 0.00
34 170 0.58 173 264 82 182 463.51 182 0.00
35 175 0.58 173 355 82 273 463.51 273 0.01
36 180 0.58 173 446 82 364 463.52 364 0.01
37 185 0.58 173 537 82 455 463.52 455 0.01
38 190 0.89 268 723 82 641 463.53 641 0.01
39 195 0.89 268 909 82 827 463.54 827 0.02
40 200 0.89 268 1,095 82 1,013 463.55 1,013 0.02
41 205 1.21 363 1,376 82 1,294 463.57 1,294 0.03
42 210 1.53 458 1,752 82 1,670 463.59 1,670 0.04
43 215 1.84 553 2,223 82 2,141 463.62 2,141 0.05
44 220 1.84 553 2,694 82 2,612 463.64 2,612 0.06
45 225 2.16 648 3,259 82 3,177 463.67 3,177 0.07
46 230 2.16 648 3,825 82 3,743 463.70 3,743 0.09
47 235 2.48 743 4,486 82 4,404 463.74 4,404 0.10
48 240 2.48 743 5,147 82 5,065 463.77 5,065 0.12
49 245 2.79 838 5,903 82 5,821 463.81 5,821 0.13
50 250 3.11 933 6,754 82 6,672 463.86 6,672 0.15
51 255 3.43 1,028 7,699 82 7,617 463.91 7,617 0.17
52 260 3.74 1,123 8,740 82 8,658 463.97 8,658 0.20
53 265 4.06 1,218 9,876 82 9,794 464.03 9,794 0.22
54 270 4.06 1,218 11,012 82 10,930 464.09 10,930 0.25
55 275 4.38 1,313 12,242 82 12,160 464.16 12,160 0.28

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 11 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 6 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
56 280 4.69 1,408 13,568 82 13,486 464.23 13,486 0.31
57 285 5.01 1,503 14,989 82 14,907 464.31 14,907 0.34
58 290 5.01 1,503 16,409 82 16,327 464.38 16,327 0.37
59 295 5.33 1,598 17,925 82 17,843 464.46 17,843 0.41
60 300 5.64 1,693 19,536 82 19,454 464.55 19,454 0.45
61 305 7.22 2,167 21,621 82 21,539 464.65 21,539 0.49
62 310 8.81 2,642 24,181 82 24,100 464.78 24,100 0.55
63 315 9.76 2,927 27,027 82 26,945 464.92 26,945 0.62
64 320 10.71 3,212 30,157 82 30,075 465.07 30,075 0.69
65 325 12.29 3,687 33,762 82 33,680 465.25 33,680 0.77
66 330 15.14 4,542 38,222 82 38,140 465.47 38,140 0.88
67 335 3.43 1,028 39,168 82 39,086 465.51 39,086 0.90
68 340 0.26 78 39,164 82 39,082 465.51 39,082 0.90
69 345 0.19 57 39,139 82 39,057 465.51 39,057 0.90
70 350 0.16 47 39,104 82 39,022 465.51 39,022 0.90
71 355 0.09 28 39,051 82 38,969 465.51 38,969 0.89
72 360 0.06 19 38,988 82 38,906 465.50 38,906 0.89
Basin Depth Analysis

Page 12 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft) 1 15 0.03 31 31 246 - 463.50 - 0.00
2 30 0.05 46 46 246 - 463.50 - 0.00
3 45 0.05 46 46 246 - 463.50 - 0.00
4 60 0.07 61 61 246 - 463.50 - 0.00
5 75 0.05 46 46 246 - 463.50 - 0.00
6 90 0.05 46 46 246 - 463.50 - 0.00
7 105 0.05 46 46 246 - 463.50 - 0.00
8 120 0.07 61 61 246 - 463.50 - 0.00
9 135 0.07 61 61 246 - 463.50 - 0.00
10 150 0.07 61 61 246 - 463.50 - 0.00
11 165 0.08 76 76 246 - 463.50 - 0.00
12 180 0.08 76 76 246 - 463.50 - 0.00
13 195 0.08 76 76 246 - 463.50 - 0.00
14 210 0.08 76 76 246 - 463.50 - 0.00
15 225 0.08 76 76 246 - 463.50 - 0.00
16 240 0.10 92 92 246 - 463.50 - 0.00
17 255 0.10 92 92 246 - 463.50 - 0.00
18 270 0.12 107 107 246 - 463.50 - 0.00
19 285 0.12 107 107 246 - 463.50 - 0.00
20 300 0.14 122 122 246 - 463.50 - 0.00
21 315 0.10 92 92 246 - 463.50 - 0.00
22 330 0.12 107 107 246 - 463.50 - 0.00
23 345 0.14 122 122 246 - 463.50 - 0.00
24 360 0.14 122 122 246 - 463.50 - 0.00
25 375 0.15 137 137 246 - 463.50 - 0.00
26 390 0.15 137 137 246 - 463.50 - 0.00
27 405 0.17 153 153 246 - 463.50 - 0.00
28 420 0.17 153 153 246 - 463.50 - 0.00
29 435 0.17 153 153 246 - 463.50 - 0.00
30 450 0.19 168 168 246 - 463.50 - 0.00
31 465 0.20 183 183 246 - 463.50 - 0.00
32 480 0.22 199 199 246 - 463.50 - 0.00
33 495 0.25 229 229 246 - 463.50 - 0.00
34 510 0.25 229 229 246 - 463.50 - 0.00
35 525 0.27 244 244 246 - 463.50 - 0.00
36 540 0.29 260 260 246 14 463.50 14 0.00
37 555 0.35 319 333 246 87 463.50 87 0.00
38 570 0.57 509 596 246 351 463.52 351 0.01
39 585 0.78 698 1,049 246 803 463.54 803 0.02
40 600 0.99 887 1,689 246 1,444 463.58 1,444 0.03
41 615 0.25 229 1,673 246 1,427 463.58 1,427 0.03
42 630 0.25 229 1,656 246 1,410 463.58 1,410 0.03
43 645 0.76 687 2,098 246 1,852 463.60 1,852 0.04
44 660 0.80 722 2,574 246 2,328 463.63 2,328 0.05
45 675 0.67 604 2,932 246 2,686 463.65 2,686 0.06
46 690 0.71 637 3,323 246 3,077 463.67 3,077 0.07
47 705 0.41 366 3,443 246 3,197 463.67 3,197 0.07
48 720 0.61 551 3,749 246 3,503 463.69 3,503 0.08
49 735 1.84 1,653 5,156 246 4,910 463.77 4,910 0.11
50 750 2.04 1,838 6,749 246 6,503 463.85 6,503 0.15
51 765 2.42 2,176 8,679 246 8,433 463.96 8,433 0.19
52 780 2.62 2,360 10,793 246 10,547 464.07 10,547 0.24
53 795 3.51 3,155 13,703 246 13,457 464.23 13,457 0.31
54 810 3.54 3,186 16,643 246 16,397 464.39 16,397 0.38
55 825 1.71 1,537 17,933 246 17,688 464.46 17,688 0.41
56 840 1.74 1,567 19,254 246 19,008 464.52 19,008 0.44
57 855 2.45 2,207 21,216 246 20,970 464.62 20,970 0.48
58 870 2.32 2,084 23,054 246 22,808 464.71 22,808 0.52

TIME BALANCE IN
BASIN
Basin Depth Analysis

Page 13 of 14 ends

Item 33.
1 JOB # 0
100 YEAR - 24 HOUR STORM EVENT

FLOW VOLUME TOTAL IN PERC TOTAL IN BASIN
UNIT (min) IN IN BASIN OUT BASIN DEPTH
PERIOD (cfs) (cuft) (cuft) (cuft) (cuft) (ft) (cuft) (acre-ft)

TIME BALANCE IN
BASIN
59 885 2.35 2,113 24,920 246 24,674 464.80 24,674 0.57
60 900 2.21 1,988 26,663 246 26,417 464.89 26,417 0.61
61 915 2.07 1,864 28,280 246 28,035 464.97 28,035 0.64
62 930 1.93 1,738 29,773 246 29,527 465.04 29,527 0.68
63 945 1.28 1,155 30,682 246 30,436 465.09 30,436 0.70
64 960 1.31 1,181 31,618 246 31,372 465.13 31,372 0.72
65 975 0.07 61 31,433 246 31,187 465.12 31,187 0.72
66 990 0.07 61 31,248 246 31,002 465.12 31,002 0.71
67 1005 0.05 46 31,048 246 30,802 465.11 30,802 0.71
68 1020 0.05 46 30,848 246 30,602 465.10 30,602 0.70
69 1035 0.08 76 30,679 246 30,433 465.09 30,433 0.70
70 1050 0.08 76 30,509 246 30,263 465.08 30,263 0.69
71 1065 0.08 76 30,340 246 30,094 465.07 30,094 0.69
72 1080 0.07 61 30,155 246 29,909 465.06 29,909 0.69
73 1095 0.07 61 29,970 246 29,724 465.05 29,724 0.68
74 1110 0.07 61 29,786 246 29,540 465.04 29,540 0.68
75 1125 0.05 46 29,586 246 29,340 465.03 29,340 0.67
76 1140 0.03 29,370 31 246 29,125 465.02 29,125 0.67
77 1155 0.05 46 29,170 246 28,925 465.01 28,925 0.66
78 1170 0.07 61 28,986 246 28,740 465.00 28,740 0.66
79 1185 0.05 46 28,786 246 28,540 464.99 28,540 0.66
80 1200 0.03 31 28,570 246 28,325 464.98 28,325 0.65
81 1215 0.05 46 28,370 246 28,125 464.97 28,125 0.65
82 1230 0.05 46 28,170 246 27,925 464.96 27,925 0.64
83 1245 0.05 46 27,970 246 27,725 464.95 27,725 0.64
84 1260 0.03 31 27,755 246 27,509 464.94 27,509 0.63
85 1275 0.05 46 27,555 246 27,309 464.93 27,309 0.63
86 1290 0.03 31 27,340 246 27,094 464.92 27,094 0.62
87 1305 0.05 46 27,140 246 26,894 464.91 26,894 0.62
88 1320 0.03 31 26,925 246 26,679 464.90 26,679 0.61
89 1335 0.05 46 26,725 246 26,479 464.89 26,479 0.61
90 1350 0.03 31 26,509 246 26,264 464.88 26,264 0.60
91 1365 0.03 31 26,294 246 26,048 464.87 26,048 0.60
92 1380 0.03 31 26,079 246 25,833 464.86 25,833 0.59
93 1395 0.03 31 25,864 246 25,618 464.85 25,618 0.59
94 1410 0.03 31 25,648 246 25,402 464.84 25,402 0.58
95 1425 0.03 31 25,433 246 25,187 464.83 25,187 0.58
96 1440 0.03 31 25,218 246 24,972 464.82 24,972 0.57
Basin Depth Analysis

Page 14 of 14 ends

Item 33.

IV STREET FLOWRATE CAPACITY
On-site street curb and gutter systems will be designed to convey runoff to the on-site retention basin systems via surface flow. The project site will be designed to ensure that surface runoff generated during the 100 year storm event can be contained within the street right of way per City of Coachella drainage standards
In terms of on-site drainage, the site is divided into 4 separate quadrants, each draining to a separate surface retention basin. Within each quadrant, the maximum tributary area contributing runoff to any single street is 5 acres. Rational method calculations based on the 100 year design storm for 5 acres drainage area are provided in this section to quantify the maximum flowrate (Q) that must be conveyed by any on-site interior street. Manning’s equation for open channel flow has then been used to show that the 100 year maximum flowrate (Q) can be contained within the street section right of way.

Q(100) MAX. = 10.92 CFS
MAX. STREET CAPACITY = 13.86 CFS

Page 1297 ends

Item 33.

Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2005 Version

7.1 Rational Hydrology Study Date: 09/25/24
File:CALHOUN100STREET.out
------------------------------------------------------------------ ------
CALHOUN 100 YEAR - 5 ACRE STUDY

------------------------------------------------------------------ ------
********* Hydrology Study Control Information ********** English (in-lb) Units used in input data file
------------------------------------------------------------------ ------
Program License Serial Number 6253
------------------------------------------------------------------ ------
Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District 1978 hydrology manual
Storm event (year) = 100.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.350(In.)
100 year, 1 hour precipitation = 1.330(In.)
Storm event year = 100.0
Calculated rainfall intensity data:
1 hour intensity = 1.330(In/Hr)
Slope of intensity duration curve = 0.5900
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++
Process from Point/Station 100.000 to Point/Station
200.000
**** INITIAL AREA EVALUATION ****
__________________________________________________________________ ____
Initial area flow distance = 1000.000(Ft.)
Top (of initial area) elevation = 450.000(Ft.)
Bottom (of initial area) elevation = 446.500(Ft.)
Difference in elevation = 3.500(Ft.)
Slope = 0.00350 s(percent)= 0.35
TC = k(0.370)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 18.171 min.

Rainfall intensity = 2.691(In/Hr) for a 100.0 year storm

Page 1298 ends

Item 33.

CONDOMINIUM subarea type
Runoff Coefficient = 0.812
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 1.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 56.00
Pervious area fraction = 0.350; Impervious fraction = 0.650 Initial subarea runoff = 10.922(CFS)
Total initial stream area = 5.000(Ac.)
Pervious area fraction = 0.350
End of computations, total study area = 5.00 (Ac.)
The following figures may
be used for a unit hydrograph study of the same area.

Area averaged pervious area fraction(Ap) = 0.350
Area averaged RI index number = 56.0

Page 1299 ends

Item 33.

Page 1300 ends

Item 33.

V APPENDIX

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Item 33.

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Item 33.

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Whitewater River Region Preliminary WQMP
Calhoun Street Subdivision
Appendix G
AGREEMENTS – CC&RS, COVENANT AND AGREEMENTS, BMP

MAINTENANCE AGREEMENTS AND/OR OTHER

MECHANISMS FOR ENSURING ONGOING OPERATION,

MAINTENANCE, FUNDING AND TRANSFER OF

REQUIREMENTS FOR THIS PROJECT-SPECIFIC WQMP
N/A

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Item 33.

Whitewater River Region Preliminary WQMP
Calhoun Street Subdivision
Appendix H
PHASE 1 ENVIRONMENTAL SITE ASSESSMENT – SUMMARY OF SITE

REMEDIATION CONDUCTED AND USE RESTRICTIONS

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Item 33.

The Altum Group
44‐600 Village Court, Suite 100
Palm Desert, California 92260
Proposal No.: BER‐23‐8‐001
Proposal for
Geotechnical Engineering Feasibility Report and
Phase I Environmental Site Assessment
Vandenburg
APN: 612‐260‐010‐6
Coachella, Riverside County, California
August 1, 2023
© 2023 Earth Systems Pacific
Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Pacific

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Item 33.

EARTH SYSTEMS
79‐811B Country Club Drive | Bermuda Dunes, CA 92203‐1244 | (760) 345‐1588 | www.earthsystems.com August 1, 2023 Proposal No.: BER‐23‐8‐001
The Altum Group
44‐600 Village Court, Suite 100
Palm Desert, California 92260
Attention: Rich Malacoff, AICP, Principal Planner
Subject: Geotechnical Engineering Feasibility Report and Phase I Environmental Site Assessment
Project: Vandenburg
APN: 612‐260‐010‐6
Coachella, Riverside County, California
Earth Systems Pacific [Earth Systems] is pleased to submit this proposal to provide geotechnical services and a Phase I Environmental Site Assessment for the above referenced project. Since 1969, the Earth Systems group of companies has provided expert geo‐professional services to assist our clients through all aspects of geotechnical and geologic engineering, environmental engineering, and construction related materials testing and inspection services. Our dedicated staff understands the diverse geotechnical, geologic, and construction‐related issues that may affect the proposed project and will work to develop practical and economical geotechnical engineering solutions through innovative approaches. We have prepared this proposal based on our understanding of preliminary project information provided by the client. We have estimated the total number of borings and our fees based on preliminary information provided by the client.

We also understand that the proposed structure/s will be developed under the regulation of the current California Building Code [CBC] (2022). Based upon the anticipated conditions, the following sections describe our understanding of the project and our anticipated scope of services in order to meet the above requirements.

This project will be managed by Mr. Kevin Paul, GE 2930, who will also oversee the engineering evaluation and report preparation, and be the Principal on the project. Mr. Mark Spykerman, EG 1174, will also oversee the interpretation of the site geologic conditions.

Environmental work on this project will be performed under the direct supervision of an Environmental Professional [EP], in accordance with the US EPA AAI and ASTM E‐1527‐13 requirements.

SITE AREA AND PROJECT UNDERSTANDING
We understand the proposed project is contained within one accessor parcel number located southwest corner of Avenue 49 and Calhoun Street, Riverside County, California. The legal address is APNs: 612‐260‐010‐6. The project is bounded by future extension of Avenue 49 to the north, Calhoun Street to the east, abandoned date palm farmland to the south and west. The APN report states the area is approximately 38.8 acres and has a high potential for liquefaction.

The site appears to have been used as a former date tree farm.

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Item 33.

August 1, 2023 2 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
The client provided site plan shows multiple improvements on the project site. The following improvements are noted:
• Three subareas containing apartment buildings, total 15.2 acres. • Residential Lots.
• Park site totaling 1.5 acres.
• Two retention basins along Calhoun Street
Note, plans showing actual building locations and other improvements have not been provided to Earth Systems at the time of drafting this proposal; hence, the reason for “feasibility level” geotechnical report. Earth Systems shall review the 100 percent concept plans to determine if the report can become a “full level” geotechnical report. The client should understand that Earth Systems could require additional exploration, lab testing, and report addendums based on the comparison of the now and future Concept Plans and other project plans.

Figure 1 Conceptual Site Plan

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Item 33.

August 1, 2023 3 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
Earth Systems assumes any new structure will be one to two‐story with slab on grade construction. Earth Systems also assumes the structure will be made of wood or metal frame construction with shallow conventional foundation. Below grade basement levels are not anticipated. We assume column loads are anticipated not to exceed approximately 50 kips for spread footings and 3 kip/LF for wall loads. Based on the type of development, appurtenant site work is anticipated to include perimeter walls, trash enclosure, asphaltic pavement, driveway approaches, PCC sidewalk, underground utilities and landscaping. If all weather roads consisting of gravel is desired, please contact Earth Systems for these design recommendations.

Preliminary grading elevations were not available at this time. We assumed that proposed grades will be approximately (+/‐3 feet) those of existing site grades. Site soils are expected to be coarse grained soils. Bedrock is not expected to be within the limits of the borings (maximum depth of 50 feet). However, groundwater may be near the 50‐foot depth of search required by the California Building Code.

The purpose of our study will be to explore the subsurface conditions and provide geotechnical recommendations for project design. Two locations will be selected prior to field explorations to perform shallow boring percolation tests for proposed storm basin infiltration. This proposal contains a brief project description, our proposed approach to the project based upon our initial assessment of site conditions and readily available information, our proposed scope of services, schedule, and proposed fee. Since detailed services may involve greater expense, we ask that our clients participate in determining the level of service, which provides adequate information for their purposes. Please review this information and our proposed scope. If you should have any questions or suggested revisionsto our scope, please do not hesitate to contact the signatory of this proposal. Our proposal is based upon the assumption that we will be provided full access to the site during normal business hours (M‐F, 7 am to 6 pm) to complete field activities and that drilling with a gasoline powered drill rig equipped with a 140‐pound hammer to drive the soil samplers can be used at the site.

PROPOSED SCOPE OF GEOTECHNICAL SERVICES
Our scope will include performing subsurface exploration, laboratory testing, and preparing one report of our findings and recommendations regarding geotechnical and geologic aspects of the project. Specific tasks are as follows:

Task 1 ‐ Literature Review
We propose to begin our services by reviewing select geologic and geotechnical literature pertaining to the project. This will include a review of various hazard, fault and geologic maps prepared by the U.S. Geological Survey, Riverside County, and other governmental agencies as they relate to the site.

Task 2 ‐ Utility Coordination, USA Layout
Each of our proposed field exploration locations will be located and marked in the field and cleared with known utility lines as identified by Underground Service Alert [USA]. Our proposed exploration locations will be located in the field by hand measuring devices such as tape or a

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Item 33.

August 1, 2023 4 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
wheel, based on the control provided, and a consumer grade hand‐held GPS (accuracy +‐ 15 feet).

The accuracy of location will be governed by the method used.

Task 3 – Field Exploration
We propose to evaluate the general subsurface conditions at the site by utilizing a rubber track rig‐mounted drill utilizing hollow‐stem auger type techniques. Borings will be performed to collect field data and soil samples to evaluate the general nature of the anticipated site soils. Our proposed exploration locations will be selected based on client provided information of the proposed improvements. Additionally, backhoe test pits on the order of 5 to 10 feet deep will be excavated to observe the depth of date palm roots.

Our planned boring exploration will include approximately five (5) exploration borings. Boring depths vary between 10 and 50 feet (50‐foot depth) in depth below the ground surface or practical refusal. Boring and pit depths are measured below the existing ground surface and will be excavated to the approximate stated depth or to practical refusal, whichever occurs first.

Boring and pit depths may be adjusted depending on conditions encountered.

A representative from Earth Systems will maintain a log of the subsurface conditions encountered and will obtain samples for visual observation, classification and laboratory testing.

Soils will be logged in general accordance with the Unified Soil Classification System. Our typical sampling interval within the borings will be approximately every 2½ to 5 feet to the full depth explored; however, sampling intervals may be adjusted depending on the materials encountered.

Bulk samples of the soil materials will be obtained. The number of blows necessary to drive either a Standard Penetration Test [SPT] sampler or a modified California‐type sampler within the borings will be recorded. The depth to groundwater will be measured, if encountered. Borings will be backfilled with the soils from the cuttings and tamped upon completion. Controlled compaction of the backfill is not proposed. Our field exploration will be provided under the direction of a Registered Engineer from our firm.

In the event that unusual site conditions not presently anticipated are encountered during the exploration, we will bring it to your attention and will discuss with you the effect of these conditions on both the estimated cost and timing of the report.

Task 4 ‐ Laboratory Testing
Laboratory tests will be performed on selected samples to evaluate the physical characteristics of the materials encountered during our field exploration. We anticipate laboratory testing may include moisture content, dry unit weight, maximum density/optimum moisture content, sieve analysis, Expansion Index, R‐value, and consolidation/collapse potential. Testing will be performed in general accordance with American Society for Testing and Materials [ASTM] or appropriate test procedure. Selected samples will also be tested for a screening level of corrosion potential (pH, electrical resistivity, water‐soluble sulfates, and water‐soluble chlorides). Earth Systems does not practice corrosion engineering; however, these test results may be used by a qualified engineer in designing an appropriate corrosion control plan for the project. The tests selected and the frequency of testing may be modified and will be based on the subsurface conditions encountered.

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Item 33.

August 1, 2023 5 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
Task 5 – Analysis and Report
Earth Systems will analyze the field data obtained, perform preliminary engineering analyses, and provide recommended design parameters for earthwork and foundations for the proposed structure/s. The results of our field exploration and engineering analysis will be summarized in a report prepared under the supervision of a Registered Engineer. Four copies of this report will be provided to the client. We anticipate that our report will include:
 A description of the proposed project including a site plan showing the approximate boring locations.
 A description of the surface and subsurface site conditions including groundwater conditions, as encountered in our field exploration.
 A description of the site geologic setting and possible associated geology‐related hazards, including liquefaction, subsidence, and seismic settlement analysis.  A discussion of regional geology and site seismicity.  A description of local and regional active faults.
 A discussion of other geologic hazards such as ground shaking, landslides, flooding, and tsunamis.
 A discussion of site conditions, including the geotechnical suitability of the site for the general type of construction proposed.
 A “General Procedure” seismic analysis including geotechnical seismic design coefficients in accordance with the 2022 CBC.
 Recommendations for imported fill (if required) for use in compacted fills.  Recommendations for foundation design including parameters for shallow foundations and building pad and subgrade preparation.
 Anticipated total and differential settlements for the recommended foundation system.  Preliminary recommendations for the mitigation of seismic induced settlement.  Recommendations for lateral earth pressures (active, at‐rest, and passive) for retaining walls, including drainage requirements, coefficients of friction and seismic earth pressures.
 Recommendations for site preparation, earthwork, and fill compaction specifications.  Discussion of anticipated excavation conditions, including shrinkage and/or bulking.  Recommendations for underground utility trench backfill and import soils.  Recommendations for stability of temporary trench excavations.  Recommendations for slabs‐on‐grade (building slabs and walkways), including recommendations for reducing the potential for moisture transmission through interior slabs.

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Item 33.

August 1, 2023 6 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
 Asphalt concrete pavement and Portland cement driveway recommendations for auto, driveways, and fire lanes (Traffic Index values of 5.0 for parking areas and 7.0 for driveways, and 5.0 for fire lanes).
 Recommendations for collapsible or expansive soils (if applicable).  Recommendations for location specific storm water infiltration rates. Note, infiltration rates will be provided in the geotechnical report.
 A discussion of the corrosion potential of the near‐surface soils encountered during our field exploration.
 An appendix, which will include a summary of the field exploration and laboratory testing program.

Task 6 – Percolation Testing for Basin Infiltration
In addition to the geotechnical explorations, two (2) borings will be drilled and used for percolation testing and soil classification. The percolation testing borings will extend no deeper than 5 feet below the ground surface. Drilling must be performed in conjunction with the geotechnical engineering exploration during our field exploration and these will be used for percolation testing in proposed infiltration systems (location to be determined by the hydraulic engineer prior to drilling operations). The percolation test values will be converted to infiltration values based on Porchet Method defined in Riverside County (accepted by San Bernardino County) Low Impact Development BMP Design Handbook: Shallow Percolation Test. Test holes will extend vertically to maximum depth of 5 feet below the existing ground surface representing the assumed bottom of the drainage facility. Perforated PVC pipe and gravel and sock will be placed into the test hole to hold it open during the test, and the test holes will be pre‐soaked and allowed to sit overnight if required.

Percolation testing will consist of adding up to 3 feet of clean water to the test holes. Adding the water will allow measuring the rate at which the water percolates into the subsurface by periodically measuring the drop in water surface over time. The tests will take about one hour if a sandy protocol is used, and will last about six hours if a clayey protocol is used (in general conformance with the standards of the Riverside County Low Impact Development BMP Design Handbook: Shallow Percolation Test. For the clayey protocol, the testing will be performed the day after the hole has been presoaked; for the sandy protocol, the testing can be performed two hours after the hole has been presoaked. Based on knowledge of the surface soils designated as sandy, we anticipate that the sandy testing protocol may apply. The tests can be performed concurrently in the various test holes.

Optional Task 7 – Private Utility Locating
As USA does not locate utilities on private property. We offer, as an optional task item, to perform private utility locating at the proposed boring locations if utility plans are not available from the owner and they would like greater assurance of not encountering a buried utility during the drilling.

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Item 33.

August 1, 2023 7 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
GEOTECHNICAL FEES
We propose to complete the proposed scope of work presented above assuming typical site conditions on a fixed‐fee basis as detailed below:

Geotechnical Engineering Report and Seismic Hazards Evaluation and Percolation Testing (Tasks 1‐6) $19,900.00
Private Utility Locating (Optional Task 7) $ 1,500.00 Typical site conditions assume reasonable accessibility for a truck mounted drill rig, permits are not required, monitoring by third parties are not required, and minimal delays for utility clearances. In the event that unusual site conditions not presently anticipated are encountered during the exploration, we will bring it to your attention and will discuss with you the effect of these conditions on both the estimated cost and timing of the reports.

Other services not included are private utility locating (unless option selected), percolation testing for leach private sewage, temporary traffic control plans & permit & devices & device setup, plan reviews, response to reviews, meetings, testing or observation during construction, or any other service not expressly detailed. If required, services in addition to the scope of work described above will be billed on a time‐and‐expense basis, based upon the Fee Schedule in effect at the time the services are provided.

Our proposal is based on the understanding that our services, as outlined in this proposal, are not subject to Prevailing Wage Law for non‐professional field staff (i.e. drillers and helpers). In the event that the Department of Industrial Relations determines that additional Prevailing Wage Law applies to the project, (client) agrees to pay to Consultant any additional compensation necessary to adjust Consultant’s employees’ wages to conform to the Prevailing Wage Law on this project.

GEOTECHNICAL SCHEDULE
Based on the requested information, we feel confident that we can provide the geotechnical engineering report as outlined in this proposal in an expeditious manner. Typically, once authorization to enter the property and a signed contract and retainer are received, we will mark respective boring locations in the field. Subsequent to field marking, we will contact Underground Service Alert which requires 48 hours notification prior to any underground excavation or drilling. Depending on subcontractor availability, we anticipate excavating our field borings within one to two weeks after the minimum 48 hour wait required by Underground Service Alert. Drilling operations will take approximately one day to complete.

Laboratory testing is anticipated to take three weeks to complete after drilling is completed. This time frame is governed by the type of testing performed as certain tests anticipated for this project require at least two weeks to run. Normal time frames from receipt of authorization to report submittal is typically about six to eight weeks. If requested, we can provide preliminary design data in the interim period before the report is finalized.

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Item 33.

August 1, 2023 8 Proposal No.: BER‐23‐8‐001
EARTH SYSTEMS PACIFIC
PROPOSED SCOPE OF ENVIRONMENTAL SERVICES
Our environmental scope will include performing a standard Phase I Environmental Site Assessment. No additional environmental services are proposed. The purpose of an ESA is to evaluate the potential for soil or groundwater contamination at a site due to the possible past use, storage, or handling of hazardous materials or petroleum products on or near the site, based on a visit to the site and a review of readily obtainable information concerning site activities and conditions. The scope of work is based on United States Environmental Protection Agency Final All Appropriate Inquiry Rule (2006) [US EPA AAI] and ASTM Standard E‐1527‐13, Standard Practice for Environmental Site Assessments. Our cost estimate is based on performing the following scope of services:

Site Reconnaissance: This will include a visual reconnaissance of the site, noting physical evidence of potential contamination or possible sources of contamination. The client/owner, tenants, and/or site personnel will be interviewed (if possible) regarding current and past site usage. The site will be photographed to document current conditions. Adjacent site uses will also be observed to evaluate their possible impact on the subject property.

Site History Investigation: The history of the site will be researched to identify past land use at and near the site related to the storage, production, or use of hazardous materials.

If possible, persons with knowledge of past site uses will be interviewed. Documents to be reviewed may include the following:
 Historical aerial photographs
 Topographic maps
 Munger Oil maps
 Fire insurance maps
 Land title information
 Local street directories
 Zoning/land use records
 Interviews with current and/or former owners, occupants, and operators  Engineering and institutional controls, such as deed restrictions and restrictive zoning to a radius of ½‐mile, if contained in publicly available lists/registries
 Tribal records of subject property and adjoining properties (if tribal land)  Local government records such as building department files  Environmental cleanup liens
 Prior investigative reports (non‐Earth Systems reports must be provided by the client)
Regulatory Agency Record Review: Many regulatory agencies compile information concerning sites that generate, store, use, and/or have released hazardous materials.

This information will be accessed by obtaining a report from a firm that specializes in maintaining a database of this type of information. The search radii for this review will be in accordance with the US EPA AAI and ASTM standard E‐1527‐13 (plus an additional distance to accommodate large sites, as appropriate). In addition, personnel at select government agencies will be contacted for information they may have regarding

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August 1, 2023 9 Proposal No.: BER‐23‐8‐001
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environmental conditions at the site or in the site vicinity. If the site or an adjacent property is known to have had a release of hazardous materials, the agency files for that site will be reviewed (if readily obtainable). We have assumed that this review will take no more than 2 hours.

Report Preparation: A report summarizing the results of the assessment will be prepared and sent to the client. The report will present our findings regarding past land use on and around the site, our opinion regarding the potential for soil or groundwater contamination at the site, and our recommendations for additional assessment of the site (if deemed appropriate). The US EPA AAI and ASTM standard E1527‐13 require the identification of gaps in the data used in evaluating the site. Data gaps encountered in the project, and their significance to the project, will be summarized. The report is normally provided in digital form (as a pdf). Up to three paper copies of the report can be provided upon request at no additional cost.

Note that the collection or analysis of samples of building materials, soil, groundwater, or air is not typically included in the scope of an ESA and is not proposed here. Assessment for the presence of molds is also not included. We do not propose to determine the degree or extent of any contamination that may be identified during this phase of work. If needed, these evaluations would normally be performed as part of a subsequent “Phase II” investigation, at an additional fee.

ENVIRONMENTAL FEES
We propose to conduct this Phase I with a normal turnaround time of 4 weeks and on a fixed‐fee basis.

Phase I Environmental Site Assessment – site has past use $4,900.00 In lieu of requesting a credit application and performing a credit check, we will invoice you for this amount when we receive authorization to proceed. That invoice must be paid before the report will be issued.

ENVIRONMENTAL SCHEDULE
Phase I ESA's typically require about four weeks to complete. Please note that some of the information required to complete the ESA may not be available within the project time‐frame.

Significant information that does not arrive by the time of publication will be reported as a data gap.

TERMS FOR SERVICE
The following terms and conditions shall be incorporated into the agreement for services and form the basis for the fees developed within. Contract terms more onerous than presented within or insurance greater than $1,000,000 typical limit could incur greater fee.

1. STUDY, MONITORING & INSPECTION: If the services include monitoring or inspection of soil, construction and/or materials, Client shall authorize and pay for Consultant to provide sufficient observation and professional inspection to permit Consultant to form opinions according to accepted statistical sampling methods as to whether the work has been performed

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August 1, 2023 10 Proposal No.: BER‐23‐8‐001
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in accordance with recommendations. Such opinions, while statistically valid, do not guaranty uniformity of conditions or materials. Similarly, soils and geology investigations do not guaranty uniformity of subsurface conditions. Client hereby represents and warrants that it has provided and shall provide to Consultant all information and sufficient advance notice necessary in order for Consultant to perform the appropriate level of services. No statement or action of Consultant can relieve Client’s contractors of their obligation to perform their work properly. Consultant has no authority to supervise or stop the work of others.

2. SITE ACCESS & UTILITIES: Client has sole responsibility for securing site access, locating utilities, and any repair.

3. BILLING AND PAYMENT: Client will pay Consultant the proposal amount or, if none is stated, according to the fee schedule in effect at the time our services are provided. Prior to initiation of fieldwork, a retainer may be required. This retainer shall be maintained throughout the project and shall be applied to the final invoice. Payment is due on presentation of invoices, and is delinquent if Consultant has not received payment within 30‐days from date of an invoice.

Client will pay an additional charge of 1‐1/2 (1.5) percent per month (or the maximum percentage allowed by law, whichever is lower) on any delinquent amount. Each payment will first be applied to accrued interest, costs and fees and then to the principal unpaid amount. All time spent and expenses incurred (including any in‐house or outside attorney's fees) in connection with collection of any delinquent amount will be paid by the Client to Consultant per Consultant's current fee schedule. Payment by Credit Card is subject to a 3% additional fee.

4. OWNERSHIP OF DOCUMENTS: Consultant owns all documents it creates and grants Client limited license to use the documents for the purposes stated in the documents.

Consultant reserves the right to withhold delivery of documents to Client until payment in full of current invoices has been received.

5. TERMINATION: This agreement may be terminated by either party effective seven (7) days from the date of written notice, or if the client suspends the work for three (3) months. In the event of termination, Consultant will be paid for services performed prior to the date of termination plus reasonable termination expenses. If Consultant has not received payment for any invoice within 30 days from the date of the invoice, or in the event of anticipatory breach by Client, Consultant may suspend performance of its services immediately and may terminate this contract.

6. RISK ALLOCATION: In order for Client to obtain the benefit of a fee which includes a lesser allowance for compensating Consultant for its litigation risk, Client agrees to indemnify, hold harmless and defend Consultant, its agents, employees, or officers, from and against any and all loss, claim, expenses, including attorney’s fees, injury, damages, liability or costs arising out of non‐design services (i.e., services other than as defined by Civil Code Section 2784) performed by Consultant on this project, except where such loss injury, damage, liability, cost, expenses or claims are the result of the sole negligence or willful misconduct of Consultant.

Client further agrees to limit the total aggregate liability of Consultant, its agents, employees, and officers to Client on the entire project, to the greater of $25,000.00 or total fees charged by Consultant, except that Consultant’s liability for willful misconduct shall not be limited. These terms may be negotiable depending on the particular facts of your project. You should consult with an attorney experienced in construction contracts and litigation regarding this provision.

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August 1, 2023 11 Proposal No.: BER‐23‐8‐001
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7. HAZARDOUS MATERIALS: Consultant is responsible only for hazardous materials brought by Consultant onto the site. Client retains ownership and responsibility in all respects for other hazardous materials and associated damage.

8. ASSIGNS AND THIRD PARTIES: This Contract is intended only to benefit the parties hereto. No person who is not a signatory to this Contract shall have any rights hereunder to rely on this Contract or on any of Consultant’s services or reports without the express written authorization of Consultant. This Contract shall not be assigned by Client without the Consultant’s written consent. This Contract is binding on any successor companies to Client or Consultant, and on the surviving corporation in the event of a merger or acquisition.

9. STANDARD OF CARE: Consultant agrees to strive to perform its services that are intended solely for the use of the Client, in a proper and professional manner in accordance with current standards of environmental practice in this community at this time. The Client agrees to pay for and look to Consultant only for such performances. No warranty or guarantee is expressed or implied. Consultant and the Client agree that there are risks of earth movement and property damage inherent in land development and repair and that Consultant has not been authorized to perform the exhaustive and economically unfeasible investigation necessary to eliminate such risks.

10. EFFECTS OF SITE EXPLORATION: It is understood that in the normal course of providing these services, Consultant may be required to access the site to perform field exploration. All boreholes will be backfilled at completion; however, some settlement should be anticipated.

Consultant will attempt to minimize the effects of the exploration operations on the site.

However, it must be understood that some damage to existing roadways, vegetation, or other improvements may occur. Consultant does not propose to restore the site to the same condition as was present prior to the exploration operations.

11. GOVERNING LAW, SURVIVAL AND FORUM SELECTION: The contract shall be governed by laws of the State of California. If any of the provisions contained in this agreement are held invalid, the enforceability of the remaining provisions will not be impaired. Limitations of liability, indemnities, representations and warranties by Client will survive termination of this agreement. The signatories represent and warrant that they are authorized by the entities on whose behalf they sign to enter into this contract and that their principals have filed fictitious business name statements, if required. All disputes between Consultant and client related to this agreement will be submitted to the court of the county where Consultant's principal place of business is located and client waives the right to remove the action to any other county or judicial jurisdiction.

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CLOSURE
If the proposed Scope of Services, Terms for Service and Fee are satisfactory, please sign in the space provided. Please return one copy to our office with the Owner Information Form. This will constitute authorization for us to proceed with work on the project. Our fee will be billed subsequent to the submission of our final report to the client. Based on the passing of Assembly Bill No. 2629, services may not commence until the execution of a written contract. This agreement can be terminated by either party by notification in writing. Earth Systems responsibility for the project will end upon completion of the services described herein or termination of the agreement, unless authorization to perform additional work and agreement for payment thereof is provided by the client. This proposal is valid for a period of 90 days. If authorized after 90 days, Earth Systems reserves the right to reconsider the fees presented herein. We look forward to assisting you on this project and we thank you for the opportunity to submit this proposal.

If you have any questions or require additional information, please do not hesitate to contact the undersigned at (760) 345‐1588.

Respectfully submitted,
EARTH SYSTEMS PACIFIC AGREED TO AND ACCEPTED
Kevin L. Paul
Vice President CLIENT NAME (IN PRINT)
PLEASE RETURN A SIGNED COPY TO SIGNATURE AND TITLE
EARTH SYSTEMS PACIFIC
____________________________________
TIN/SSN (Tax ID No. /Social Security No.)
(This information and signature above authorizes us to
review Client credit history.)
Proposal/ac/cgj/klp/mh
DATE
Check Below to Authorize Services:
□ Geotechnical Engineering Feasibility Report
□ Optional Task 7 – Private Utility Locating
□Phase I Environmental Site Assessment
Attachments: Owner Information Form
Distribution: 1/Rich Malacoff: [email protected] 1/BER File

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Whitewater River Region Preliminary WQMP
Calhoun Street Subdivision
Appendix I

PROJECT-SPECIFIC WQMP SUMMARY DATA FORM

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Rod

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Initial Study/Mitigated Negative Declaration
City of Coachella Calhoun Street Housing Development/TTM 39051 November 2025 Initial Study/Mitigated Negative Declaration F
Appendix F
Calhoun Street Housing Development Traffic Impact Analysis

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CALHOUN STREET

SUBDIVISION

TRAFFIC ANALYSIS
Reference Number Agency Date
15830-04 TA Report.docx City of Coachella September 6, 2024 PREPARED BY: Janette Cachola | [email protected] Marlie Whiteman, P.E. | [email protected]
John Kain, AICP | [email protected]

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ii

TABLE OF CONTENTS
Table of Contents ............................................................................................................................................... ii Appendices ......................................................................................................................................................... iv List of Exhibits ..................................................................................................................................................... v List of Tables ...................................................................................................................................................... vi List of Abbreviated Terms ............................................................................................................................... vii 1 Introduction............................................................................................................................................... 1

1.1 Project Overview........................................................................................................................... 1

1.2 Analysis Scenarios......................................................................................................................... 1

1.3 Study Area..................................................................................................................................... 3

1.4 Analysis Findings........................................................................................................................... 3 2 Methodologies .......................................................................................................................................... 7

2.1 Level of Service ............................................................................................................................. 7

2.2 Intersection Capacity Analysis ...................................................................................................... 7

2.3 Traffic Signal Warrant Analysis Methodology............................................................................... 9

2.4 Minimum Acceptable Levels of Service (LOS)............................................................................. 10 3 Area Conditions ...................................................................................................................................... 11

3.1 Existing Circulation Network....................................................................................................... 11

3.2 City of Coachella General Plan Circulation Element ................................................................... 11

3.3 Transit Service............................................................................................................................. 11

3.4 Pedestrian and Bicycle Facilities ................................................................................................. 11

3.5 Existing (2024) Traffic Counts ..................................................................................................... 16

3.6 Intersection Operations Analysis................................................................................................ 16

3.7 Traffic Signal Warrants Analysis.................................................................................................. 19 4 Projected Future Traffic ......................................................................................................................... 21

4.1 Project Trip Generation............................................................................................................... 21

4.2 Project Trip Distribution.............................................................................................................. 22

4.3 Modal Split.................................................................................................................................. 22

4.4 Project Trip Assignment.............................................................................................................. 22

4.5 Background Traffic ...................................................................................................................... 22

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iii
5 EAP (2026) Traffic Conditions ................................................................................................................ 29

5.1 EAP Traffic Volume Forecasts ..................................................................................................... 29

5.2 Intersection Operations Analysis................................................................................................ 29

5.3 Traffic Signal Warrants Analysis.................................................................................................. 29 6 EAPC (2026) Traffic Conditions ............................................................................................................. 33

6.1 EAPC (2026) Traffic Volume Forecasts........................................................................................ 33

6.2 Intersection Operations Analysis................................................................................................ 33

6.3 Traffic Signal Warrants Analysis.................................................................................................. 33

6.4 Cumulative Improvements.......................................................................................................... 36 7 Cumulative and Site Access Improvements ........................................................................................ 37

7.1 Recommended Cumulative Improvement.................................................................................. 37

7.2 ON‐Site and Site‐Adjacent Improvements.................................................................................. 37 8 References ............................................................................................................................................... 41

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iv

APPENDICES
Appendix 1.1: Traffic Study Scope
Appendix 1.2: VMT Screening
Appendix 3.1: Traffic Counts –2024
Appendix 3.2: Existing (2024) Conditions Intersection Operations Analysis Worksheets Appendix 3.3: Traffic Signal Warrant Analysis Worksheets Appendix 5.1: EAP (2026) Conditions Intersection Operations Analysis Worksheets Appendix 6.1: EAPC (2026) Conditions Intersection Operations Analysis Worksheets

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v

LIST OF EXHIBITS
Exhibit 1-1: Preliminary Site Plan ..................................................................................................................... 2 Exhibit 1-2: Study Area ....................................................................................................................................... 4 Exhibit 3-1: Existing Number of Through Lanes and Intersection Controls ............................................. 12 Exhibit 3-2: City of Coachella General Plan Circulation Element ............................................................... 13 Exhibit 3-3: City of Coachella General Plan Roadway Cross-Sections ....................................................... 14 Exhibit 3-4: Existing Pedestrian and Bike Facilities ...................................................................................... 15 Exhibit 3-5: Existing (2024) Traffic Volumes .................................................................................................. 17 Exhibit 4-1: Project Trip Distribution .............................................................................................................. 24 Exhibit 4-2: Project Only Traffic volumes ...................................................................................................... 25 Exhibit 4-3: Cumulative Development Location Map .................................................................................. 26 Exhibit 5-1: EAP (2026) Traffic Volumes ......................................................................................................... 31 Exhibit 6-1: EAPC (2026) Traffic Volumes ...................................................................................................... 34 Exhibit 7-1: Site Access Recommendations .................................................................................................. 39 Exhibit 7-2: Recommended Intersection Improvements for
EAP (2026) and EAPC (2026) Conditions ................................................................................... 40

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vi

LIST OF TABLES
Table 1-1: Intersection Analysis Locations ...................................................................................................... 3 Table 1-2: Level of Service Summary ............................................................................................................... 5 Table 2-1: Signalized Intersection LOS Thresholds ........................................................................................ 8 Table 2-2: Unsignalized Intersection LOS Thresholds ................................................................................... 9 Table 2-3: Traffic Signal Warrant Analysis Locations ................................................................................... 10 Table 3-1: Intersection Analysis for Existing (2024) Conditions ................................................................. 18 Table 4-1: Project Trip Generation Summary ............................................................................................... 21 Table 4-2: Cumulative Development Land Use Summary .......................................................................... 27 Table 5-1: Intersection Analysis for EAP (2026) Conditions ........................................................................ 32 Table 6-1: Intersection Analysis for EAPC (2026) Conditions ...................................................................... 35 Table 7-1: Existing Plus Ambient Plus Project Plus Cumulative (EAPC) Fair Share Calculations ............ 37

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LIST OF ABBREVIATED TERMS
(1) Reference
ADT Average Daily Traffic
CAMUTCD California Manual on Uniform Traffic Control Devices Caltrans California Department of Transportation
EAP Existing Plus Ambient Plus Project
EAPC Existing Plus Ambient Plus Project Plus Cumulative HCM Highway Capacity Manual
ITE Institute of Transportation Engineers
LOS Level of Service
PHF Peak Hour Factor
Project Calhoun Street Subdivision
sf Square Feet
TA Traffic Analysis

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Calhoun Street Subdivision Traffic Analysis
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1 1 INTRODUCTION
This report presents the results of the traffic analysis (TA) for Calhoun Street Subdivision (“Project”), located at the southwest corner of Calhoun Street and Avenue 49 in the City of Coachella, as shown on Exhibit 1-1.

The purpose of this TA is to evaluate the potential circulation system deficiencies that may result from the development of the proposed Project, and recommend improvements to achieve acceptable circulation system operational conditions. This TA has been prepared based in accordance with the County of Riverside’s Transportation Analysis Guidelines for Level of Service & Vehicle Miles Traveled (December 2020), as the City of Coachella utilizes the County guidelines. (1) Urban Crossroads, Inc. prepared a traffic study scoping package (included in Appendix 1.1) which was reviewed by City’s consultant prior to the preparation of this report.

1.1 PROJECT OVERVIEW
The Project is proposed to consist of 259 single family residential units and a 1.5-acre park on approximately 40 acres. It is anticipated that the Project would be developed by year 2026. A preliminary site plan of the proposed Project is shown in Exhibit 1-1. Access to the Project will be provided via Access 1 at Calhoun Street (full access) and Access 2 at Avenue 49 (full access).

In order to develop the traffic characteristics of the proposed Project, trip-generation rates provided in the Institute of Transportation Engineers (ITE) Trip Generation (11th Edition, 2021) are utilized.

The Project is anticipated to generate a total of 2,517 trip-ends per day with 192 AM peak hour trips and 250 PM peak hour trips. The assumptions and methods used to estimate the Project’s trip generation characteristics are discussed in greater detail in Section 4.1 Project Trip Generation of this report.

1.2 ANALYSIS SCENARIOS
For the purposes of this traffic study, potential deficiencies to traffic and circulation have been assessed for each of the following conditions:
 Existing (2024) Conditions
 Existing plus Ambient plus Project (EAP) (2026) Conditions  Existing plus Ambient plus Project plus Cumulative (EAPC) (2026) Conditions

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2

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3 For the existing study area intersections, traffic count data has been collected in January and June, 2024 during the AM peak period of 7:00 AM to 9:00 AM and PM peak period of 4:00 PM to 6:00 PM.

The Existing plus Ambient plus Project (EAP) conditions analysis determines the potential near-term cumulative circulation system deficiencies with the Project but without known cumulative projects.

To account for background traffic growth, an ambient growth factor from Existing conditions of 4.04% (2% per year, compounded annually over 2 years) is included for EAP (2026) traffic conditions. The ambient growth is consistent with the growth used by other projects within the City of Coachella.

The Existing plus Ambient plus Project plus Cumulative (EAPC) (2026) traffic conditions analysis determines the potential cumulative circulation system deficiencies, including the Project and other known cumulative projects. The cumulative project list was compiled from information provided in the City of Coachella website.

1.3 STUDY AREA
The Project study area was defined in coordination with the City of Coachella. Exhibit 1-2 presents the study area and intersection analysis locations. The intersections listed in Table 1-1 were selected for this TA with City of Coachella technical staff concurrence.

TABLE 1-1: INTERSECTION ANALYSIS LOCATIONS
# Intersection # Intersection
1 Calhoun St. / Dr. Carreon Bl. 5 Jackson St. / Avenue 49 - Odlum Dr. 2 Calhoun St. / Avenue 48 6 Calhoun St. / Access 1
3 Calhoun St. / Avenue 49 7 Access 2 / Avenue 49
4 Calhoun St. / Avenue 50

1.4 ANALYSIS FINDINGS
This section provides a summary of the analysis results for Existing (2024), EAP (2026), and EAPC (2026) conditions. Table 1-2 presents a summary of study area LOS conditions for each analysis scenario.

1.4.1 EXISTING (2024) CONDITIONS
For Existing (2024) traffic conditions the unsignalized study area intersections of Calhoun Street / Dr.

Carreon Boulevard (#1), Calhoun Street / Avenue 49 (#3), and Jackson Street / Avenue 49 – Odlum Drive (#5) are operating at unacceptable level of service (LOS “E” or worse). Each of these three locations meet the traffic volume warrants for installation of a traffic signal based upon existing traffic counts.
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# Intersection AM PM AM PM AM PM
1 Calhoun St. / Dr. Carreon Bl.
- Without Improvements
- With Improvements N/A N/A
2 Calhoun St. / Avenue 48
3 Calhoun St. / Avenue 49
- Without Improvements
- With Improvements N/A N/A
4 Calhoun St. / Avenue 50
5 Jackson St. / Avenue 49 - Odlum Dr.
- Without Improvements
- With Improvements N/A N/A
6 Calhoun St. / Access 1 N/A N/A
7 Access 2 / Avenue 49 N/A N/A
Legend:
= A - D = E = F
F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Report.xlsx]1-2_LOS Summary TABLE 1-2: LEVEL OF SERVICE (LOS) SUMMARY
Existing
(2024)
EAP
(2026)
EAPC
(2026)
5

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6 1.4.2 EXISTING PLUS AMBIENT PLUS PROJECT (EAP) (2026) CONDITIONS For EAP (2026) traffic conditions, there are no additional intersections anticipated to operate at unacceptable LOS during peak hours beyond the three locations which have existing deficiencies.

Installation of a traffic signal at each of the deficient intersections of Calhoun Street / Dr. Carreon Boulevard (#1), Calhoun Street / Avenue 49 (#3), and Jackson Street / Avenue 49 – Odlum Drive (#5) are anticipated to address intersection operational deficiencies.

Although the intersection of Calhoun Street / Access 1 (#6) operates at an acceptable LOS for EAP conditions, this location meets the volume warrants for installation of a traffic signal.

1.4.3 EXISTING PLUS AMBIENT PLUS PROJECT PLUS CUMULATIVE (EAPC) (2026) CONDITIONS For EAPC (2026) traffic conditions, there are no additional intersections anticipated to operate at unacceptable LOS during peak hours. Similar to EAP conditions, installation of traffic signal at the three deficient unsignalized intersections are anticipated to address intersection operational deficiencies.

Detailed Project fair share calculations, for each peak hour, are provided in Table 7-1 for the three locations where traffic signals are warranted for all analysis scenarios (existing, EAP, and EAPC).

Site-adjacent improvements are listed in Section 7.2 and include the following:
 Project to construct Avenue 49 as a 2-lane roadway (40 feet curb-to-curb width) from Jackson Street to the Project’s westerly site boundary.
 Project to construct Avenue 49 at its ultimate southerly half section width as a Primary Arterial with bicycle facility from the Project’s westerly site boundary to the Project’s easterly site boundary (Calhoun Street).
 Project to widen Calhoun Street at its ultimate westerly half-section width as a Collector Roadway with Bicycle facility from Project’s northerly site boundary (Avenue 49) to the Project’s southerly boundary.  Project to implement a new traffic signal at the Calhoun Street / Avenue 49 (#3) intersection, with potential future reimbursement contingent upon cumulative development activity.  Access to the adjacent public park to be provided from Calhoun Street, subject to park development access and parking plans (to be determined).

1.4.4 VEHICLE MILES TRAVELED (VMT)
Appendix 1.2 contains the approved VMT screening analysis which was performed in a separate document (Calhoun Street Subdivision Vehicle Miles Traveled (VMT) Screening, Urban Crossroads, June 18, 2024) and no further VMT is required.

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7 2 METHODOLOGIES
This section of the report presents the methodologies used to perform the traffic analyses summarized in this report. The methodologies described are consistent with the County of Riverside TIA Guidelines. (1)

2.1 LEVEL OF SERVICE
Traffic operations of roadway facilities are described using the term “Level of Service” (LOS). LOS is a qualitative description of traffic flow based on several factors, such as speed, travel time, delay, and freedom to maneuver. Six levels are typically defined ranging from LOS A, representing completely free-flow conditions, to LOS F, representing breakdown in flow resulting in stop-and-go conditions.

LOS E represents operations at or near Capacity, an unstable level where vehicles are operating with the minimum spacing for maintaining uniform flow.

2.2 INTERSECTION CAPACITY ANALYSIS
The definitions of LOS for interrupted traffic flow (flow restrained by the existence of traffic signals and other traffic control devices) differ slightly depending on the type of traffic control. The LOS is typically dependent on the quality of traffic flow at the intersections along a roadway. The 7th Edition Highway Capacity Manual (HCM) methodology expresses the LOS at an intersection in terms of delay time for the various intersection approaches. (2)The HCM uses different procedures depending on the type of intersection control.

2.2.1 SIGNALIZED INTERSECTIONS
The City of Coachella requires signalized intersection operations analysis based on the methodology described in the HCM. (2) Intersection LOS operations are based on an intersection’s average control delay. Control delay includes initial deceleration delay, queue move-up time, stopped delay, and final acceleration delay. For signalized intersections LOS is related to the average control delay per vehicle and is correlated to a LOS designation as described on Table 2-1.

The traffic modeling and signal timing optimization software package Synchro (Version 12) has been utilized to analyze signalized intersections. Synchro is a macroscopic traffic software program that is based on the signalized intersection capacity analysis as specified in the HCM. Macroscopic level models represent traffic in terms of aggregate measures for each movement at the study intersections. Equations are used to determine measures of effectiveness such as delay and queue length. The level of service and Capacity analysis performed by Synchro takes into consideration optimization and coordination of signalized intersections within a network.

The peak hour traffic volumes are adjusted using a peak hour factor (PHF) to reflect peak 15-minute volumes. Common practice for LOS analysis is to use a peak 15-minute rate of flow. However, flow rates are typically expressed in vehicles per hour.
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8 The PHF is the relationship between the peak 15-minute flow rate and the full hourly volume (e.g. PHF = [Hourly Volume] / [4 x Peak 15-minute Flow Rate]). The use of a 15-minute PHF produces a more detailed analysis as compared to analyzing vehicles per hour. Existing PHFs have been used for all analysis scenarios. Per the HCM, PHF values over 0.95 often are indicative of high traffic volumes with capacity constraints on peak hour flows while lower PHF values are indicative of greater variability of flow during the peak hour. (2)
TABLE 2-1: SIGNALIZED INTERSECTION LOS THRESHOLDS

2.2.2 UNSIGNALIZED INTERSECTIONS
The City of Coachella requires the operations of unsignalized intersections be evaluated using the methodology described in the HCM. (2) The LOS rating is based on the weighted average control delay expressed in seconds per vehicle (see Table 2-2). At two-way or side-street stop-controlled intersections, LOS is calculated for each controlled movement and for the left turn movement from the major street, as well as for the intersection as a whole. For approaches composed of a single lane, the delay is computed as the average of all movements in that lane. Delay for the intersection is reported for the worst individual movement at a two-way stop-controlled intersection.

Average Control Delay Level of Serice,
(Seconds), V/C < 1.0 V/C < 1.01
Operations with very low delay occurring with favorable progression and/or short cycle length.
0 to 10.00 A
Operations with low delay occurring with good progression and/or short cycle lengths.

10.01 to 20.00 B
Operations with average delays resulting from fair
progression and/or longer cycle lengths. Individual cycle failures begin to appear.

20.01 to 35.00 C
Operations with longer delays due to a combination of
unfavorable progression, long cycle lengths, or high V/C ratios. Many vehicles stop and indvidual cycle failures are noticeable.

35.01 to 55.00 D
Operations with high delay values indicating poor
progression, long cycle lengths, and high V/C ratios.

Individual cycle failures are frequent occurrences. This is considered to be the limit of acceptable delay.

55.01 to 80.00 E
Operation with delays unacceptable to most drivers
occurring due to over saturation, poor progression, or very long cycle lengths.

80.01 and up F
Source: HCM, 7th Edition
1 if V/C is greater than 1.0 then LOS is F per HCM
Description
8

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9 TABLE 2-2: UNSIGNALIZED INTERSECTION LOS THRESHOLDS

2.3 TRAFFIC SIGNAL WARRANT ANALYSIS METHODOLOGY
The term “signal warrants” refers to the list of established criteria used by Caltrans and other public agencies to quantitatively justify or determine the potential need for installation of a traffic signal at an otherwise unsignalized intersection. This TA uses the signal warrant criteria presented in the latest edition of the Caltrans California Manual on Uniform Traffic Control Devices (CA MUTCD). (3) The signal warrant criteria for Existing study area intersections are based upon several factors, including volume of vehicular and pedestrian traffic, frequency of accidents, and location of school areas. The CA MUTCD indicates that the installation of a traffic signal should be considered if one or more of the signal warrants are met. (3) Specifically, this TA utilizes the Peak Hour Volume-based Warrant 3 as the appropriate representative traffic signal warrant analysis for existing traffic conditions and for all future analysis scenarios for existing unsignalized intersections. Warrant 3 is appropriate to use for this TA because it provides specialized warrant criteria for intersections with rural characteristics. For the purposes of this study, the speed limit was the basis for determining whether Urban or Rural warrants were used for a given intersection. Urban warrants have been used as posted speed limits on the major roadways with unsignalized intersections are 40 miles per hour or below and rural warrants have been used on roadways with speeds greater than 40 miles per hour.

Future intersections that do not currently exist have been assessed regarding the potential need for new traffic signals based on future average daily traffic (ADT) volumes, using the Caltrans planning level ADT-based signal warrant analysis worksheets. Similarly, the speed limit has been used as the basis for determining the use of Urban and Rural warrants.

Traffic signal warrant analyses were performed for the following unsignalized study area intersections shown in Table 2-3:

Average Control Delay Level of Serice,
(Seconds), V/C < 1.0 V/C < 1.01
Little or no delays. 0 to 10.00 A
Short traffic delays. 10.01 to 15.00 B
Average traffic delays. 15.01 to 25.00 C
Long traffic delays. 25.01 to 35.00 D
Very long traffic delays. 35.01 to 50.00 E
Extreme traffic delays with intersections capacity exceeded. >50.00 F Source: HCM, 7th Edition
1 if V/C is greater than 1.0 then LOS is F per HCM
Description
9

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10 TABLE 2-3: TRAFFIC SIGNAL WARRANT ANALYSIS LOCATIONS # Intersection # Intersection
1 Calhoun St. / Dr. Carreon Bl. 6 Calhoun St. / Access 1 3 Calhoun St. / Avenue 49 7 Access 2 / Avenue 49
5 Jackson St. / Avenue 49 - Odlum Dr.

The Existing conditions traffic signal warrant analysis is presented in the subsequent section, Section 3 Area Conditions of this report. The traffic signal warrant analyses for future conditions are presented in Section 5 EAP (2026) Traffic Conditions and Section 6 EAPC (2026) Traffic Conditions of this report.

It is important to note that a signal warrant defines the minimum condition under which the installation of a traffic signal might be warranted. Meeting this threshold condition does not require that a traffic control signal be installed at a particular location, but rather, that other traffic factors and conditions be evaluated in order to determine whether the signal is truly justified. It should also be noted that signal warrants do not necessarily correlate with LOS. An intersection may satisfy a signal warrant condition and operate at or above acceptable LOS or operate below acceptable LOS and not meet a signal warrant.

2.4 MINIMUM ACCEPTABLE LEVELS OF SERVICE (LOS)
For the purposes of this analysis, the following thresholds of significance have been applied to study area intersections located within the City of Coachella to identify significant impacts through a comparison of Existing and EAP traffic conditions:
 If an intersection is projected to operate at an acceptable level of service (i.e., LOS D or better) under Existing traffic conditions and the addition of project traffic is expected to cause the intersection to operate at an unacceptable level of service (LOS E or F), the impact is considered significant;  If an intersection is projected to operate at LOS E or LOS F under Existing, and the addition of project traffic, the impact is considered significant.

Cumulative traffic impacts are deficiencies that are not directly caused by the Project, but occur as a result of regional growth combined with that or other nearby cumulative development projects. The Project’s contribution to a particular cumulative transportation deficiency is deemed cumulatively considerable if the Project adds significant traffic to the forecasted deficiency. A Project’s contribution to a cumulatively considerable impact can be reduced to less than significant if the Project is required to implement or fund its fair share of improvements designed to alleviate the potential cumulative impact. If full funding of future cumulative improvements is not reasonably assured, a temporary unmitigated cumulative impact may occur until the needed improvement is fully funded and constructed.

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11 3 AREA CONDITIONS
This section provides a summary of the existing circulation network, the City of Coachella General Plan Circulation Network, and a review of existing peak hour intersection operations and traffic signal warrant analyses.

3.1 EXISTING CIRCULATION NETWORK
Pursuant to the Project scope (Appendix 1.1), the study area includes 5 existing intersections as shown previously on Exhibit 1-2, which have been agreed upon with City staff. Exhibit 3-1 illustrates the number of through traffic lanes for existing roadways and traffic controls for study area intersections.

3.2 CITY OF COACHELLA GENERAL PLAN CIRCULATION ELEMENT
As noted previously, the Project site is located at the southwest corner of Tyler Street and Avenue 53 in the City of Coachella. Exhibit 3-2 shows the City of Coachella General Plan Circulation Element, with planned roadway classifications. Exhibit 3-3 illustrates the City of Coachella General Plan roadway cross-sections.

Calhoun Street is classified as a Collector with Bicycle Facility in the study area.

Dr. Carreon Boulevard and Avenue 49 are classified as a Primary Arterial with Bicycle Facility in the study area.

Avenue 48 and Avenue 50 are classified as a Major Arterial with Bicycle Facility in the study area.

3.3 TRANSIT SERVICE
The City of Coachella is currently served by the SunLine Transit Agency; currently, Route 8 is located along Calhoun Street (between Avenue 48 and Avenue 50), Dr. Carreon Boulevard (between Jackson Street & Van Buren Street), Avenue 48 (between Calhoun Street & Van Buren Street), Avenue 50 (east of Calhoun Street) in the study area. Transit service is reviewed and updated by Sunline periodically to address ridership, budget and community demand needs. Changes in land use can affect these periodic adjustments which may lead to either enhanced or reduced service where appropriate.

3.4 PEDESTRIAN AND BICYCLE FACILITIES
The existing pedestrian facilities within the study area are shown on Exhibit 3-4. As shown on Exhibit 3-4, existing on-street bike lanes are located along the Calhoun Street, Avenue 48, and Avenue 50.

Sidewalks generally exist on Avenue 48 and Avenue 50. Some portions of the sidewalk exist on Calhoun Street, Jackson Street, Dr. Carreon Boulevard, Odlum Drive, and Avenue 49.

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16 3.5 EXISTING (2024) TRAFFIC COUNTS
The intersection LOS analysis is based on the traffic volumes observed during the peak hour conditions using traffic count data collected in August 2024. The City of Coachella experiences seasonal population variations over the course of the year, with relatively higher populations during the winter months from January to the end of March. To compensate for the discrepancy, counts not taken during this peak winter period (January 2 to March 31) require seasonal adjustments. A 20% increase is applied to counts taken in August to estimate peak season. This factor is consistent with other nearby jurisdictions within the Coachella Valley area.

The following peak hours were selected for analysis:
 Weekday AM Peak Hour (peak hour between 7:00 AM and 9:00 AM)  Weekday PM Peak Hour (peak hour between 4:00 PM and 6:00 PM) The raw manual peak hour turning movement traffic count data sheets are included in Appendix 3.1.

The weekday AM and PM peak hour count data are representative of typical peak hour traffic conditions in the study area. There were no observations made in the field that would indicate atypical traffic conditions on the count dates, such as construction activity that would prevent or limit roadway access and detour routes. These raw turning volumes have been flow conserved between intersections with limited access, no access and where there are currently no uses generating traffic.

Existing weekday peak hour intersection volumes are shown on Exhibit 3-5.

Existing weekday ADT volumes are also shown on Exhibit 3-5. Where actual 24-hour tube count data was not available, Existing ADT volumes were based upon factored intersection peak hour counts collected by Urban Crossroads, Inc. using the following formula for each intersection leg:

Weekday PM Peak Hour (Approach Volume + Exit Volume) x 12.658 = Leg Volume A comparison of the PM peak hour and daily traffic volumes of various roadway segments within the study area indicated that the peak-to-daily relationship is approximately 7.90 percent. As such, the above equation utilizing a factor of 12.658 estimates the ADT volumes on the study area roadway segments assuming a peak-to-daily relationship of approximately 7.90 percent (i.e., 1/0.070 = 12.658) and was assumed to sufficiently estimate average daily traffic (ADT) volumes for planning-level analyses.

3.6 INTERSECTION OPERATIONS ANALYSIS
Existing peak hour traffic operations have been evaluated for the study area intersections based on the analysis methodologies presented in Section 2.2 Intersection Capacity Analysis of this report. The intersection operations analysis results are summarized on Table 3-1, which indicates that no study area intersections operate at unacceptable LOS (LOS “E” or worse). The intersection operations analysis worksheets are included in Appendix 3.2 of this TA.

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Delay3 Level of
Traffic Northbound Southbound Eastbound Westbound (secs.) Service # Intersection Control1 L T R L T R L T R L T R AM PM AM PM 1 Calhoun St. / Dr. Carreon Bl. AWS 1 1 1 1 2 0 1 1 1 1 1 0 >80 28.7 F D 2 Calhoun St. / Avenue 48 TS 120120130130 32.5 28.6 C C 3 Calhoun St. / Avenue 49 AWS 0 1 0 1 1 1 0 0 0 0 1! 0 51.2 20.3 F C 4 Calhoun St. / Avenue 50 TS 120120120120 33.1 28.5 C C 5 Jackson St. / Avenue 49 - Odlum Dr. AWS 1* 1002110d000 51.9 23.0 F C 6 Calhoun St. / Access 1 --
7 Access 2 / Avenue 49 --
1 TS = Traffic Signal; AWS = All Way Stop
2 When a right turn is designated, the lane can either be striped or unstriped. To function as a right turn lane there must be sufficient width for right turning vehicles to travel outside the through lanes.
3 Per the Highway Capacity Manual (7th Edition), overall average intersection delay and level of service are shown for intersections with a traffic signal or all way stop control. For intersections with cross street stop control, the delay and level of service for the worst individual movement (or movements sharing a single lane) are shown.

F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Report.xlsx]E L = Left; T = Through; R = Right; d = Defacto Right Turn Lane; 0.5 = Shared Lane; 1! = Shared Left/Through/Right lane; Future Intersection
Future Intersection
* = Left-Turn accommodated within two-way left turn lane (TWLTL) striped median TABLE 3-1: INTERSECTION ANALYSIS FOR EXISTING (2023) CONDITIONS Intersection Approach Lanes2
18

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19 3.7 TRAFFIC SIGNAL WARRANTS ANALYSIS
Traffic signal warrants for Existing traffic conditions are based on 2024 peak hour intersection turning volumes (see Appendix 3.3). For Existing (2024) traffic conditions, the following three unsignalized study area intersections currently meets traffic volume warrants for installation of a traffic signal.  Calhoun Street / Dr. Carreon Boulevard (#1)
 Calhoun Street / Avenue 49 (#3)
 Jackson Street / Avenue 49 – Odlum Drive (#5)

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21 4 PROJECTED FUTURE TRAFFIC
This section presents the traffic volumes estimated to be generated by the Project, as well as the Project’s trip assignment onto the study area roadway network.

The Project is proposed to consist of 259 single family residential units and a 1.5-acre park with dog run on approximately 40 acres.

It is anticipated that the Project will be operational by year 2026. Access to the Project will be provided via Access 1 at Calhoun Street (full access) and Access 2 at Avenue 49 (full access)

4.1 PROJECT TRIP GENERATION
Trip generation represents the amount of traffic which is both attracted to and produced by a development. Determining traffic generation for a specific project is therefore based upon forecasting the amount of traffic that is expected to be both attracted to and produced by the specific land uses being proposed for a given development.

In order to develop the traffic characteristics of the proposed project, the trip generation rates provided in the Institute of Transportation Engineers (ITE) Trip Generation (11th Edition, 2021) have been utilized (4).

Table 4-1 shows the vehicle trip generation rates for the Project, as well as the vehicle trip generation summary with daily and peak hour trip generation estimates. As shown on Table 4-1, the Project is anticipated to generate a total of 2,517 trip-ends per day with 192 AM peak hour trips and 250 PM peak hour trips.

TABLE 4-1: PROJECT TRIP GENERATION SUMMARY
Trip Generation Rates1
Land Use
ITE LU
Code Quantity2
AM Peak Hour PM Peak Hour
In Out Total In Out Total Daily
Single Family Detached 210 259 DU 0.18 0.52 0.70 0.59 0.35 0.94 9.43 Park with Dog Run3 -- 1.5 AC 3.25 3.25 6.50 2.25 2.25 4.50 50.00 Trip Generation Results
Land Use
ITE LU
Code Quantity2
AM Peak Hour PM Peak Hour
In Out Total In Out Total Daily
Single Family Detached 210 259 DU 47 135 182 153 91 244 2,442 Park with Dog Run -- 1.5 AC 5 5 10 3 3 6 75
TOTAL 52 140 192 156 94 250 2,517 1 Trip Generation Source: Institute of Transportation Engineers (ITE), Trip Generation Manual, 11th Edition (2021). 2 DU = Dwelling Unit; AC = Acre
3 Since ITE does not have trip rates for a park with dog run, similar use based on SANDAG's City park is utilized to account for higher park activity related to the dog run use.

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22 4.2 PROJECT TRIP DISTRIBUTION
The Project trip distribution and assignment process represents the directional orientation of traffic to and from the Project site. The trip distribution pattern is heavily influenced by the geographical location of the site, the location of surrounding uses, and proximity to the surrounding highway network. Trip distribution patterns proposed for the Project are illustrated on Exhibit 4-1.

4.3 MODAL SPLIT
The potential for Project trips to be reduced by the use of public transit, walking or bicycling have not been included as part of the Project’s estimated trip generation. Essentially, the Project’s traffic projections are “conservative” in that these alternative travel modes would reduce the forecasted traffic volumes.

4.4 PROJECT TRIP ASSIGNMENT
The assignment of traffic from the Project area to the adjoining roadway system is based upon the Project trip generation, trip distribution, and the arterial highway and local street system improvements that would be in place by the time of initial occupancy of the Project. Based on the identified Project traffic generation and trip distribution patterns, Project weekday ADT and weekday peak hour intersection turning movement volumes are shown on Exhibit 4-2.

4.5 BACKGROUND TRAFFIC
Future year traffic forecasts have been based upon background (ambient) growth at 2% per year for 2026 traffic conditions. The total ambient growth is 4.04% for 2026 traffic conditions. This ambient growth rate is added to existing traffic volumes to account for area-wide growth not reflected by cumulative development projects. Ambient growth has been added to daily and peak hour traffic volumes on surrounding roadways, in conjunction with traffic generated by the development of future projects that have been approved but not yet built and/or for which development applications have been filed and are under consideration by governing agencies.

Exhibit 4-3 illustrates the cumulative development location map. The cumulative projects listed are those that would generate traffic and would contribute traffic to study area intersections. A summary of cumulative development projects and their proposed land uses are shown on Table 4-2. If applicable, the traffic generated by individual cumulative projects was manually added to the EAP forecasts to ensure that traffic generated by the listed cumulative development projects on Table 4-2 are reflected as part of the background traffic.
22

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23 The near-term traffic analysis includes the following traffic conditions, with the various traffic components:
 EAP (2026)
o Existing (2024) volumes
o Ambient growth traffic (4.04% over 2 years)
o Project traffic
 EAPC (2026)
o Existing (2024) volumes
o Ambient growth traffic (4.04% over 2 years)
o Project traffic
o Cumulative development traffic

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SITE
15 14
1 2
3 4
5 6
7 9
8 10
11 12
13 16
17 MONROE ST
50TH AVE

JACKSON ST
52ND AVE

INDIO BLVD
AVENUE 48
AVENUE 46

DILLON RD HARRISON ST

GOLF CENTER PKY

GRAPEFRUIT BLVD

INDIO BLVD

GRAPEFRUIT BLVD
%&'(10
·|}þ86
54TH AVE

CALHOUN ST
AVENUE 44

VAN BUREN ST
AVENUE 45
51ST AVE

REQUA AVE
53RD AVE

MILES AVE
AVENUE 53
AVENUE 51

OASIS ST
ODLUM DR 49TH AVE
6TH ST

FREDERICK ST
AVENUE 49

CABAZON AVE

HARRISON ST

HEIFITZ DR

DOCTOR CARREON BLVD

SIERRA AVE
CO
M
M

E RCE ST

DILLON AVE
WAYNE
ST

VALLEY RD

CALICO AVE

VALENCIA AVE

CA R IBE AVE

DATE A VE

COCHR A N DR

HOOV ER AVE
AVENUE 47

DISN EY DR

JOHN NOBLES AVE

SLATE DR
O

ATES LN
AVENUE 46

DOUMA ST
POE CT

LAPIS DRAUSTIN DR

CALLE AVILA

PIKE PL

CALLE EL SOL

REBECCA CT

CALLE RUIZ

ZENDA DR

HIGGINS CT

BALBOA ST

DATE AVE

HARRISON ST
51ST AVE
INDIO

COACHELLA

LA QUINTA
N_
EXHIBIT 4-3: CUMULATIVE DEVELOPMENT MAP
URBAN CROSSROADS Calhoun Street Subdivision Traffic Analysis 15830 - CD.mxd
26

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27 TABLE 4-2: CUMULATIVE DEVELOPMENT LAND USE SUMMARY
TAZ Project Land Use Quantity Units1
1 TT 38072 Single Family Residential 173 DU
2 Mariposa Pointe Single Family Residential 155 DU
3 Sevilla II Single Family Residential 204 DU
4 Encanto Single Family Residential 112 DU
5 Glenroy Hotel Project
Resort casitas/bungalows 620 RM
Hotel 130 RM
Restaurant 3.6 TSF
Retail Cannabis 3.12 TSF
General Store 2.5 TSF
Coffee shop with drive thru 2.5 TSF
6 Rancho Flores 2 Single Family Residential 124 DU
7 Sevilla by Pulte Single Family Residential 232 DU
8 Placita Dolores Huerta Multifamily Residential 110 DU 9 Fountainhead Plaza
(NEC 1st St. & Cesar Chavez St.)
Supermarket 20.422 TSF
Fast-Food Restaurant 2.6 TSF
Coffee Shop w/ Restaurant 2.1 TSF
10 Tripoli Mixed-Use Multifamily Residential 108 DU
11 Villa Verde Apartments Multifamily Residential 152 DU 12 Bellissima (Tract 31978) Single Family Residential 111 DU 13 West Coast Self Storage Self-Storage Facility 62 TSF 14 Indio Public Safety Campus
(NEC Jackson St. & Dr. Carreon Bl.)
Fire Station Expansion 4.1 TSF
Police Headquarters Expansion 44 EMP
Government Office Complex 30.1 TSF
15 Coachella Medical Center
(North of Dr. Carreon Bl., b/w Monroe & Arabia) Skilled Nursing Facility 288 Beds 16 Tower Market Convenience Mkt. w/ Pumps 12 VFP
17 Frederick St. Residential
(NWC Frederick/Ave. 52) Single Family Residential 256 DU 1 DU = Dwelling Units; TSF = Thousand Square Feet; RM = Rooms; EMP = Employees; VFP = Vehicle Fueling Positions

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29 5 EAP (2026) TRAFFIC CONDITIONS
This section discusses the traffic forecasts for Existing plus Ambient plus Project (EAP) conditions and the resulting intersection operations and traffic signal warrant analyses.

The lane configurations and traffic controls assumed to be in place for EAP (2026) conditions are consistent with those shown previously on Exhibit 3-1, with the exception driveways and those facilities assumed to be constructed by the project to provide site access are assumed to be in place for EAP (2026) conditions (e.g., intersection and roadway improvements at the projects’ frontage and driveways).

5.1 EAP TRAFFIC VOLUME FORECASTS
This scenario includes Existing traffic volumes plus an ambient growth factor of 4.04% and the addition of project traffic. The weekday ADT and weekday peak hour intersection turning movement volumes which can be expected for EAP (2026) traffic conditions are shown on Exhibit 5-1.

5.2 INTERSECTION OPERATIONS ANALYSIS
EAP peak hour traffic operations have been evaluated for the study area intersections based on the analysis methodologies presented in Section 2 Methodologies of this TA.

The intersection analysis results summarized in Table 5-1, indicate that the following intersections are anticipated to continue to operate at an unacceptable LOS during peak hours under EAP conditions, without installation of the traffic signal that is currently warranted for existing conditions.  Calhoun Street / Dr. Carreon Boulevard (#1)
 Calhoun Street / Avenue 49 (#3)
 Jackson Street / Avenue 49 – Odlum Drive (#5)
The intersection operations analysis worksheets for EAP traffic conditions are included in Appendix

5.1 of this TA.

5.3 TRAFFIC SIGNAL WARRANTS ANALYSIS
The traffic signal warrant analysis for EAP (2026) traffic conditions provided in Appendix 3.3. For EAP conditions, the intersection of Calhoun Street / Access 1 (#6) meets the volume warrants for installation of a traffic signal (see Appendix 3.3).

As mentioned previously, it is important to note that a signal warrant defines the minimum condition under which the installation of a traffic signal might be warranted. Meeting this threshold condition does not require that a traffic control signal be installed at a particular location, but rather, that other traffic factors and conditions be evaluated in order to determine whether the signal is truly justified.

It should also be noted that signal warrants do not necessarily correlate with LOS. 29

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30 An intersection may satisfy a signal warrant condition and operate at or above acceptable LOS or operate below acceptable LOS and not meet a signal warrant.

Installation of a traffic signal is currently not recommended at Calhoun Street / Access 1 (#6) intersection for the following reasons:
 This intersection is anticipated to operate at an acceptable LOS for EAP (2026) conditions with crossstreet stop control.  Access to the Project site is also provided at the Access 2 / Avenue 49 (#7) intersection, which is anticipated to operate at LOS “A” during peak hours for both EAP and EAPC conditions.  This intersection is also anticipated to operate at an acceptable LOS for EAPC (2026) conditions with cross-street stop control.

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Delay3 Level of
Traffic Northbound Southbound Eastbound Westbound (secs.) Service # Intersection Control1 L T R L T R L T R L T R AM PM AM PM 1 Calhoun St. / Dr. Carreon Bl.
- With Existing All-Way Stop AWS 1 1 1 1 2 0 1 1 1 1 1 0 >80 41.7 F E - With Traffic Signal Improvement TS 111120111110 39.0 31.9 D C 2 Calhoun St. / Avenue 48 TS 120120130130 33.7 30.3 C C 3 Calhoun St. / Avenue 49
- With Existing All-Way Stop AWS 1 1011 1 0 1! 0 0 1! 0 >80 46.2 F E - With Traffic Signal Improvement TS 1 1011 1 0 1! 0 0 1! 0 10.4 7.9 B A 4 Calhoun St. / Avenue 50 TS 1201201 2 0120 34.3 29.3 C C 5 Jackson St. / Avenue 49 - Odlum Dr.
- With Existing All-Way Stop AWS 1* 1 0 1* 2110d0 1! 0 74.2 35.0 F D - With Traffic Signal Improvement TS 1 10 1 2 1 0.5 0.5 d 0 1! 0 12.4 9.2 B A 6 Calhoun St. / Access 1 CSS 1 100100 1! 0000 27.3 25.1 D D 7 Access 2 / Avenue 49 CSS 0 1! 00000 1 0 0.5 0.5 0 8.7 8.8 A A 1 TS = Traffic Signal; CSS = Cross-Street Stop; AWS = All Way Stop 2 When a right turn is designated, the lane can either be striped or unstriped. To function as a right turn lane there must be sufficient width for right turning vehicles to travel outside the through lanes.
3 Per the Highway Capacity Manual (7th Edition), overall average intersection delay and level of service are shown for intersections with a traffic signal or all way stop control. For intersections with cross street stop control, the delay and level of service for the worst individual movement (or movements sharing a single lane) are shown.

F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Report.xlsx]EAP TABLE 5-1: INTERSECTION ANALYSIS FOR EAP (2026) CONDITIONS Intersection Approach Lanes2
L = Left; T = Through; R = Right; d = Defacto Right Turn Lane; 0.5 = Shared Lane; 1! = Shared Left/Through/Right lane; * = Left-Turn accommodated within two-way left turn lane (TWLTL) striped median; 1 = Improvement 32

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33 6 EAPC (2026) TRAFFIC CONDITIONS
This section discusses the methods used to develop Existing plus Ambient plus Project plus Cumulative (EAPC) (2026) traffic forecasts, and the resulting intersection operations and traffic signal warrant analyses.

The lane configurations and traffic controls assumed to be in place for EAPC (2026) conditions are consistent with those shown previously on Exhibit 3-1, with the exception of the following:
 Project driveways and those facilities assumed to be constructed by the Project to provide site access are also assumed to be in place for EAPC conditions (e.g., intersection and roadway improvements along the Project’s frontage and driveways).
 If applicable, driveways and those facilities assumed to be constructed by cumulative developments to provide site access are also assumed to be in place for EAPC conditions (e.g., intersection and roadway improvements along the cumulative development’s frontages and driveways).

6.1 EAPC (2026) TRAFFIC VOLUME FORECASTS
This scenario consists of existing traffic volumes plus an ambient growth factor of 4.04% plus traffic from pending and approved but not yet constructed known development projects in the area plus the Project.

The weekday ADT and weekday peak hour volumes which can be expected for EAPC (2026) traffic conditions are shown on Exhibit 6-1.

6.2 INTERSECTION OPERATIONS ANALYSIS
The intersection analysis results summarized in Table 6-1, indicate that the following intersections are anticipated to continue to operate at an unacceptable LOS during peak hours under EAPC conditions, without installation of the traffic signal that are currently warranted for existing conditions.  Calhoun Street / Dr. Carreon Boulevard (#1)
 Calhoun Street / Avenue 49 (#3)
 Jackson Street / Avenue 49 – Odlum Drive (#5)
The intersection operations analysis worksheets for EAPC traffic conditions are included in Appendix

6.1 of this TA.

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Delay3 Level of
Traffic Northbound Southbound Eastbound Westbound (secs.) Service # Intersection Control1 L T R L T R L T R L T R AM PM AM PM 1 Calhoun St. / Dr. Carreon Bl.
- With Existing All-Way Stop AWS 1 1 1 1 2 0 1 1 1 1 1 0 >80 >80 F F - With Traffic Signal Improvement TS 111120111110 43.6 32.6 D C 2 Calhoun St. / Avenue 48 TS 120120130130 34.7 31.0 C C 3 Calhoun St. / Avenue 49
- With Existing All-Way Stop AWS 1 1011 1 0 1! 0 0 1! 0 >80 75.4 F F - With Traffic Signal Improvement TS 1 1011 1 0 1! 0 0 1! 0 10.9 7.8 B A 4 Calhoun St. / Avenue 50 TS 1201201 2 0120 37.8 30.5 D C 5 Jackson St. / Avenue 49 - Odlum Dr.
- With Existing All-Way Stop AWS 1* 1 0 1* 2110d0 1! 0 >80 47.9 F E - With Traffic Signal Improvement TS 1 10 1 2 1 0.5 0.5 d 0 1! 0 15.7 11.9 B B 6 Calhoun St. / Access 1 CSS 1 100100 1! 0000 32.2 30.6 D D 7 Access 2 / Avenue 49 CSS 0 1! 00000 1 0 0.5 0.5 0 8.7 8.8 A A 1 TS = Traffic Signal; CSS = Cross-Street Stop; AWS = All Way Stop 2 When a right turn is designated, the lane can either be striped or unstriped. To function as a right turn lane there must be sufficient width for right turning vehicles to travel outside the through lanes.
3 Per the Highway Capacity Manual (7th Edition), overall average intersection delay and level of service are shown for intersections with a traffic signal or all way stop control. For intersections with cross street stop control, the delay and level of service for the worst individual movement (or movements sharing a single lane) are shown.

F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Report.xlsx]EAPC TABLE 6-1: INTERSECTION ANALYSIS FOR EAPC (2026) CONDITIONS Intersection Approach Lanes2
* = Left-Turn accommodated within two-way left turn lane (TWLTL) striped median; 1 = Improvement L = Left; T = Through; R = Right; d = Defacto Right Turn Lane; 0.5 = Shared Lane; 1! = Shared Left/Through/Right lane; 35

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36 6.3 TRAFFIC SIGNAL WARRANTS ANALYSIS
The traffic signal warrant analysis worksheets for EAPC (2026) traffic conditions are provided in Appendix 3.3. For EAPC conditions, no additional study area intersections meet the volume warrants for installation of a traffic signal (see Appendix 3.3).

As mentioned previously, a signal warrant defines the minimum condition under which the installation of a traffic signal might be warranted. Meeting this threshold condition does not require that a traffic control signal be installed at a particular location, but rather, that other traffic factors and conditions be evaluated in order to determine whether the signal is truly justified. It should also be noted that signal warrants do not necessarily correlate with LOS. An intersection may satisfy a signal warrant condition and operate at or above acceptable LOS or operate below acceptable LOS and not meet a signal warrant.

Installation of a traffic signal at the intersection of Calhoun Street / Access 1 (which was previously warranted under EAP 2026 conditions) is not currently recommended since this intersection is anticipated to continue to operate at an acceptable LOS under EAPC (2026) conditions as a crossstreet stop controlled intersection.

6.4 CUMULATIVE IMPROVEMENTS
The provision of traffic signal control addresses the off-site intersection operational deficiency for EAPC (2026) conditions at the intersections of Calhoun Street / Dr. Carreon Boulevard (#1), Calhoun Street / Avenue 49 (#3), and Jackson Street / Avenue 49 – Odlum Drive (#5). The effectiveness of this recommended signal improvement at the abovementioned intersections are presented in Table 6-1 for EAPC (2026) traffic conditions.

The intersection operations analysis worksheets for EAPC (2026) traffic conditions, with this traffic signal improvement, are included in Appendix 6.1 of this TA. 36

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37 7 CUMULATIVE AND SITE ACCESS IMPROVEMENTS

7.1 RECOMMENDED CUMULATIVE IMPROVEMENTS
The provision of traffic signal control addresses the off-site intersection operational deficiency for EAPC (2026) conditions at the intersections of Calhoun Street / Dr. Carreon Boulevard (#1), Calhoun Street / Avenue 49 (#3), and Jackson Street / Avenue 49 – Odlum Drive (#5).

Detailed fair share calculations, for each peak hour, are provided below (see Table 7-1).

TABLE 7-1: EXISTING PLUS AMBIENT PLUS PROJECT PLUS CUMULATIVE (EAPC)

FAIR SHARE CALCULATIONS
# Intersection
Existing
(2024)
Traffic
EAPC
(2026)
Traffic3
Project
Only
Traffic
Total
New
Traffic1
Project
Fair Share
(%)2
1 Calhoun St. / Dr. Carreon Bl.
• AM Peak Hour 2,002 2,357 58 355 16.3%
• PM Peak Hour 1,585 1,962 75 377 19.9%
3 Calhoun St. / Avenue 49
• AM Peak Hour 1,159 1,403 96 244 39.3%
• PM Peak Hour 1,050 1,350 125 300 41.7%
5 Jackson St. / Avenue 49 - Odlum Dr.
• AM Peak Hour 1,209 1,413 38 204 18.6%
• PM Peak Hour 1,253 1,505 50 252 19.8%
1 Total New Traffic = (EAPC 2026 - Existing Traffic)
2 Project Fair Share % = (Project Only Traffic / Total New Traffic) 3 Existing Plus Ambient Plus Project Plus Cumulative (2026) Conditions F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Report.xlsx]7-1 FairShare

7.2 ON-SITE AND SITE-ADJACENT IMPROVEMENTS
The following recommendations are based on the minimum improvements needed to accommodate site access and maintain acceptable peak hour operations for the proposed Project. On-site and site adjacent recommendations are shown on Exhibit 7-1.
 Project to construct Avenue 49 as a 2-lane roadway (40 feet curb-to-curb width) from Jackson Street to the Project’s westerly site boundary.
 Project to construct Avenue 49 at its ultimate southerly half section width as a Primary Arterial with bicycle facility from the Project’s westerly site boundary to the Project’s easterly site boundary (Calhoun Street).
37

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38  Project to widen Calhoun Street at its ultimate westerly half-section width as a Collector Roadway with Bicycle facility from Project’s northerly site boundary (Avenue 49) to the Project’s southerly boundary.  Project to implement a new traffic signal at the Calhoun Street / Avenue 49 (#3) intersection, with potential future reimbursement contingent upon cumulative development activity.  Access to the adjacent public park to be provided from Calhoun Street, subject to park development access and parking plans (to be determined).

Exhibit 7-2 shows the following site access and site adjacent intersection improvements:
#3 – Calhoun Street / Avenue 49
 Provide a separate northbound left turn lane.
 Modify southbound approach striping to provide a separate southbound right turn lane.  Provide a shared eastbound left/thru/right lane.
#6 – Calhoun Street / Access 1
 Provide a separate northbound left turn lane.
 Provide a shared eastbound left/right turn lane.
#7 – Access 1 / Avenue 49
 Provide a shared northbound left/right turn lane.
 Provide a shared eastbound thru/right turn lane.
 Provide a shared westbound left/thru lane.
38

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ENG
39

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41 8 REFERENCES

1. Riverside County. Transportation Analysis Guidelines for Level of Service & Vehicle Miles Traveled.

Riverside County : s.n., December 2020.

2. Transportation Research Board. Highway Capacity Manual (HCM), 7th Edition. s.l. : National Academy of Sciences, 2022.

3. California Department of Transportation. California Manual on Uniform Traffic Control Devices (CA MUTCD). [book auth.] California Department of Transportation. California Manual on Uniform Traffic Control Devices (CA MUTCD). 2014, Updated March 30, 2021 (Revision 6).

4. Institute of Transportation Engineers. Trip Generation Manual. 11th Edition, 2021.

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APPENDIX 1.1: TRAFFIC STUDY SCOPE

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TAGSA v03092022

SCOPING AGREEMENT FOR TRANSPORTATION LOS ANALYSIS
This letter acknowledges the Riverside County Transportation Department requirements for transportation level of service analysis of the following project. The analysis must follow the Riverside County Transportation Department Transportation Analysis Guidelines, December 2020.

Case No.

Related Cases
Project Name:

Project Address:

Project Description:

Traffic Consultant Applicant/Developer
Name:

Address:

Telephone:

E-mail:

Current GP Land Use Proposed Land Use
Current Zoning Proposed Zoning
A. Trip Generation Source:

Current Trip Generation Proposed Trip Generation
In Out Total In Out
AM Trips6DWXUGD\0RUQLQJ
PM Trips6XQGD\$IWHUQRRQ
Internal Trip Allowance Yes No ( % Trip Discount)
Pass-By Trip Allowance Yes No ( % Trip Discount)
A pass-by trip discount of 25% is allowed for appropriate land uses. The pass-by trips at adjacent study area intersections and project driveways shall be indicated on a report figure.

B. Trip Geographic Distribution: N % S % E % W %
(attach exhibit for detailed assignment)
C. Background Traffic
Project Build-out Year: Annual Ambient Growth Rate: %
Phase Year(s)
Other projects to be analyzed:

Model/Forecast methodology
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VLQJOHIDPLO\GHWDFKHGUHVLGHQWLDOXQLWVDQGDFUHSDUNZLWKGRJUXQ Marlie Whiteman, P.E., Urban Crossroads, Inc. 7HUUD1RYD3ODQQLQJ 5HVHDUFK,QF1LFROH&ULVWH 1133 Camelback St. #8329
Newport Beach, CA 92658
714.585.0574
[email protected]
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2 1.1-1

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TAGSA v03092022
D. Study intersections: (NOTE: Subject to revision after other projects, trip generation and distribution are determined, or comments from other agencies.)

1. 6.

2. 7.

3. 8.

4. 9.

5. 10.

E. Study Roadway Segments: (NOTE: Subject to revision after other projects, trip generation and distribution are determined, or comments from other agencies.)

1. 6.

2. 7.

3. 8.

4. 9.

5. 10.

F. Other Jurisdictional
Is this project within a City’s Sphere of Influence or one-mile radius of City boundaries? Yes No If yes, name of jurisdiction(s):

G. Site Plan (please attach reduced copy)
H. Specific issues to be addressed in the Study (in addition to the standard analysis described in the Guideline) (To be filled out by Transportation Department) (NOTE: If the traffic study states that “a traffic signal is warranted” (or “a traffic signal appears to be warranted,” or similar statement) at an existing unsignalized intersection under existing conditions, 8-hour approach traffic volume information must be submitted in addition to the peak hourly turning movement counts for that intersection.) I. Existing Conditions
Traffic count data must be new or recent. Provide traffic count dates if using other than new counts.

Date of counts______________________________________________________________________ *NOTE* Traffic Study Submittal Form and appropriate fee must be submitted with this form.

Recommended by: Approved Scoping Agreement
Traffic Consultant Date Date
Scoping Agreement Submitted on
Revised on
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1.1-2

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Item 33.

DATE: August 14, 2024
TO: Mr. Andrew Simmons, P.E., City of Coachella
FROM: John Kain and Marlie Whiteman, Urban Crossroads, Inc.

JOB NO: 15830-02 LOS Scope.docx
CALHOUN STREET SUBDIVISION – LEVEL OF SERVICE (LOS)

ANALYSIS SCOPE
Urban Crossroads, Inc. is pleased to submit the following LOS traffic study scope for the proposed Calhoun Street Subdivision development (Project). The Project is located at the southwest corner of Calhoun Street and Avenue 49 in the City of Coachella. The following evaluation is based on the County of Riverside’s Transportation Analysis Guidelines for Level of Service & Vehicle Miles Traveled (December 2020), as the City of Coachella utilizes the County guidelines.

PROJECT DESCRIPTION
It is our understanding that the Project is to consist of 258 dwelling units and a 1.5- acre park with dog run on approximately 40 acres. A preliminary site plan for the proposed Project is shown on Exhibit 1.

Access to the Project is provided via Access 1 at Calhoun Street (full access), Access 2 at Avenue 49 (full access), and Access 3 at Calhoun Street (right-in/right-out only access for the park).

STUDY AREA
Exhibit 2 presents the study area intersection analysis locations. Study area intersections will be evaluated using the HCM 7 methodology. Count data will be collected during the AM and PM peak hours on a typical weekday.

ANALYSIS SCENARIOS
The analysis of peak hour operations at study area intersections will be provided for the following analysis scenarios:
 Existing (2024)
 Existing Plus Ambient Growth Plus Project (2026) Conditions (EAP) o EAP with Improvements (if needed)
 Existing Plus Ambient Growth Plus Cumulative (2026) Conditions (EAC) o EAC with Improvements (if needed)
 Existing Plus Ambient Growth Plus Project Plus Cumulative (2026) Conditions (EAPC) o EAPC with Improvements (if needed)
EAP traffic conditions will be utilized to determine direct Project traffic impacts, while the EAPC (2026) analysis will be utilized to determine the Project’s cumulatively considerable/direct impacts (subject to payment of fees/fair share).

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Mr. Andrew Simmons, P.E., City of Coachella
August 14, 2024

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15830-02 LOS Scope.docx
Based on the traffic analysis results, the TA will indicate new improvement requirements and fair share contribution for the proposed Project.

STUDY AREA
Per the County’s traffic study guidelines, the study area has been developed by including locations where the Project is anticipated to contribute 50 or more peak hour trips within a 5- mile radius of the Project. Exhibit 2 presents the study area intersection analysis locations. The study area intersections will be evaluated using the HCM 7 methodology.

AMBIENT GROWTH ASSUMPTIONS
An ambient growth rate of 2.0 percent per year is proposed for the study area intersections which will be compounded for each year to the Project’s Opening Year of 2026 (in addition to cumulative development traffic overlays). The growth rate is consistent with the growth rate utilized by the County of Riverside.

TRIP GENERATION
Trip generation represents the amount of traffic that is attracted and produced by a development, and is based upon the specific land uses planned for a given project. Table 1 presents the trip generation rates and the resulting trip generation summary for the proposed Project. The trip generation rates used for this analysis are based upon information collected by the Institute of Transportation Engineers (ITE) as provided in their Trip Generation manual, 11th Edition, 2021. As shown in Table 1, the Project is anticipated to generate a total of 2,508 trip-ends per day with 190 AM peak hour trips and 248 PM peak hour trips.

TRIP DISTRIBUTION
Trip distribution is the process of identifying the probable destinations, directions, or traffic routes that will be utilized by Project traffic. The potential interaction between the planned land use and surrounding regional access routes are considered, to identify the route where the Project traffic would distribute. The trip distribution pattern is heavily influenced by the geographical location of the site, the location of surrounding uses, and the proximity to the regional freeway system. Exhibits 3 and 4 illustrate the outbound and inbound trip distribution patterns for the Project, respectively.

PROJECT TRAFFIC VOLUMES
The assignment of traffic from the Project area to the adjoining roadway system is based upon the Project trip generation, trip distribution, and the arterial street system improvements that would be in place by the time of initial occupancy of the Project. Based on the identified Project traffic generation and trip distribution patterns, Project Only Average Daily Traffic (ADT) volumes and AM and PM peak hour intersection turning movement volumes are shown on Exhibit 5.

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In Out Total In Out Total
Single Family Detached 210 258 DU 0.18 0.52 0.70 0.59 0.35 0.94 9.43 Park with Dog Run3 -- 1.5 AC 3.25 3.25 6.50 2.25 2.25 4.50 50.00 In Out Total In Out Total
Single Family Detached 210 258 DU 46 134 180 152 90 242 2,433 Park with Dog Run -- 1.5 AC 5 5 10 3 3 6 75
51 139 190 155 93 248 2,508
F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Scope.xlsx]15830 - TG 3 Since ITE does not have trip rates for a park with dog run, similar use based on SANDAG's City park is utilized to account for higher park activity related to the dog run use.

TOTAL
1 Trip Generation Source: Institute of Transportation Engineers (ITE), Trip Generation Manual, 11th Edition (2021). 2 DU = Dwelling Unit; AC = Acre
Land Use
ITE LU
Code Quantity2
AM Peak Hour PM Peak Hour
Daily
Trip Generation Results
Land Use
ITE LU
Code Quantity2
AM Peak Hour PM Peak Hour
Daily
TABLE 1: PROJECT TRIP GENERATION SUMMARY
Trip Generation Rates1

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Mr. Andrew Simmons, P.E., City of Coachella
August 14, 2024

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15830-02 LOS Scope.docx

LEVEL OF SERVICE (LOS) CRITERIA AND THRESHOLDS OF SIGNIFICANCE The City of Coachella’s current General Plan applies LOS D as a performance threshold for roadway segments and intersections.

The following thresholds of significance will be applied to study area intersections to identify significant impacts through a comparison of Existing and EAP traffic conditions:
 If an intersection is projected to operate at an acceptable level of service (i.e., LOS D or better) under Existing traffic conditions and the addition of project traffic is expected to cause the intersection to operate at an unacceptable level of service (i.e., LOS E or F), the impact is considered significant;  If an intersection is projected to operate at LOS E or LOS F under Existing, with the addition of project traffic, the impact is considered significant.

EXISTING COUNT DATA
New traffic counts will be conducted during a typical weekday when local schools are in session and operating on a typical bell schedule. No adjustments are proposed to the traffic counts for the baseline traffic condition with the exception of volume balancing between closely spaced intersections. Traffic counts are scheduled and will be conducted on August 27th with school in full session and not during music festival weekends.

Intersection turning movement counts will be conducted at the study area intersection locations for weekday AM (7-9AM) and weekday PM (4-6PM).

CITY GENERAL PLAN CIRCULATION ELEMENT
The adopted City of Coachella General Plan Circulation Element is shown on Exhibit 6. Exhibit 7 shows the City of Coachella General Plan roadway cross-sections.

CUMULATIVE DEVELOPMENT
It is requested that City staff review the list of cumulative development projects (shown on Exhibit 8 and listed on Table 2) and any additional information for projects that should be included in this traffic study that may not be reflected Exhibit 8.

Information pertaining to project location, land use, and intensity are necessary for consideration and to estimate trip generation.

If you have any questions, please contact us directly at [email protected] for John or [email protected] for Marlie.

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SITE
15 14
1 2
3 4
5 6
7 9
8 10
11 12
13 16 MONROE ST
50TH AVE

JACKSON ST
52ND AVE

INDIO BLVD
AVENUE 48
AVENUE 46

DILLON RD HARRISON ST

GOLF CENTER PKY

GRAPEFRUIT BLVD

INDIO BLVD

GRAPEFRUIT BLVD
%&'(10
·|}þ86
54TH AVE

CALHOUN ST
AVENUE 44

VAN BUREN ST
AVENUE 45
51ST AVE

REQUA AVE
53RD AVE

MILES AVE
AVENUE 53
AVENUE 51

OASIS ST
ODLUM DR 49TH AVE
6TH ST

FREDERICK ST
AVENUE 49

CABAZON AVE

HARRISON ST

HEIFITZ DR

DOCTOR CARREON BLVD

SIERRA AVE
CO
M
M

E RCE ST

DILLON AVE
WAYNE
ST

VALLEY RD

CALICO AVE

VALENCIA AVE

CA R IBE AVE

DATE A VE

COCHR A N DR

HOOV ER AVE
AVENUE 47

DISN EY DR

JOHN NOBLES AVE

SLATE DR
O

ATES LN
AVENUE 46

DOUMA ST
POE CT

LAPIS DRAUSTIN DR

CALLE AVILA

PIKE PL

CALLE EL SOL

REBECCA CT

CALLE RUIZ

ZENDA DR

HIGGINS CT

BALBOA ST

DATE AVE

HARRISON ST
51ST AVE
INDIO

COACHELLA

LA QUINTA
N_
EXHIBIT 8: CUMULATIVE DEVELOPMENT MAP
URBAN CROSSROADS Calhoun Street Subdivision Traffic Analysis 15830 - CD.mxd

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TAZ Project Land Use Quantity Units1
1 TT 38072 Single Family Residential 173 DU
2 Mariposa Pointe Single Family Residential 155 DU
3 Sevilla II Single Family Residential 204 DU
4 Encanto Single Family Residential 112 DU
Resort casitas/bungalows 620 RM
Hotel 130 RM
Restaurant 3.6 TSF
Retail Cannabis 3.12 TSF
General Store 2.5 TSF
Coffee shop with drive thru 2.5 TSF
6 Rancho Flores 2 Single Family Residential 124 DU
7 Sevilla by Pulte Single Family Residential 232 DU
8 Placita Dolores Huerta Multifamily Residential 110 DU Supermarket 20.422 TSF
Fast-Food Restaurant 2.6 TSF
Coffee Shop w/ Restaurant 2.1 TSF
10 Tripoli Mixed-Use Multifamily Residential 108 DU
11 Villa Verde Apartments Multifamily Residential 152 DU 12 Bellissima (Tract 31978) Single Family Residential 111 DU 13 West Coast Self Storage Self-Storage Facility 62 TSF Fire Station Expansion 4.1 TSF
Police Headquarters Expansion 44 EMP
Government Office Complex 30.1 TSF
15 Coachella Medical Center
(North of Dr. Carreon Bl., b/w Monroe & Arabia) Skilled Nursing Facility 288 Beds 16 Tower Market Convenience Mkt. w/ Pumps 12 VFP
F:\UXRjobs\_15600_16000\_15800\15830\02_LOS\Excel\[15830 - Scope.xlsx]15830-C TABLE 2: CUMULATIVE DEVELOPMENT LAND USE SUMMARY
9 Fountainhead Plaza
(NEC 1st St. & Cesar Chavez St.)
Indio Public Safety Campus
(NEC Jackson St. & Dr. Carreon Bl.)
14 5 Glenroy Hotel Project
1 DU = Dwelling Units; TSF = Thousand Square Feet; RM = Rooms; EMP = Employees; VFP = Vehicle Fueling Positions

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15830-03 VMT.docx
June 18, 2024
Mr. Andrew Simmons, P.E.

City of Coachella
53990 Enterprise Way
Coachella, CA 92236

CALHOUN STREET SUBDIVISION VEHICLE MILES TRAVELED (VMT) SCREENING Mr. Andrew Simmons, P.E.,
Urban Crossroads, Inc. is pleased to provide the following Vehicle Miles Traveled (VMT) Screening for the Calhoun Street Subdivision development (Project), which is located at the southwest corner of Calhoun Street and Avenue 49 in the City of Coachella.

PROJECT OVERVIEW
It is our understanding that the Project is to consist of 258 dwelling units and an 1.5 acre park with dog run on approximately 40 acres. A preliminary site plan for the proposed Project is shown on Exhibit 1. Access to the Project is provided via two full access driveways (Access 1 at Calhoun Street and Access 2 at Avenue 49), and one right-in/right-out only access for the park (Access 3 at Calhoun Street).

BACKGROUND
Changes to California Environmental Quality Act (CEQA) Guidelines were adopted in December 2018, which requires all lead agencies to adopt VMT as a replacement for automobile delay-based level of service (LOS) as the new measure for identifying transportation impacts for land use projects. This statewide mandate went into effect July 1, 2020. To aid in this transition, the Governor’s Office of Planning and Research (OPR) released a Technical Advisory on Evaluating Transportation Impacts in CEQA (December of 2018) (Technical Advisory) (1). Based on OPR’s Technical Advisory, the County of Riverside adopted their Transportation Analysis Guidelines for Level of Service Vehicle Miles Traveled (December of 2020) (County Guidelines) (2). The City of Coachella utilizes the adopted County Guidelines.

Consistent with County Guidelines, projects should evaluate available screening criteria based on their location and project type to determine if a presumption of a less than significant transportation impact can be made. The following project screening thresholds were selected for review based on their applicability to the proposed Project:
• Small Projects Screening
• High Quality Transit Areas (HQTA) Screening
• Map-Based Screening
• Local Essential Service Screening

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Mr. Andrew Simmons, P.E.

City of Coachella
June 18, 2024

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SMALL PROJECTS SCREENING
County Guidelines identify those projects forecasted to generate greenhouse gas (GHG) emissions below 3,000 Metric Tons of Carbon Dioxide Equivalent (MTCO2e) per year are also assumed to cause a less than significant VMT impact.1 The County Guidelines provides a list of land use types based on quantity (i.e., dwelling units or square footage) and provides a typical development potential to be below the 3,000 MTCO2e per year. Single Family Housing projects less than or equal to 110 dwelling units have been identified to meet the County threshold2 .

The Project quantity of 258 dwelling units is more than the residential VMT screening criteria.

Small Projects screening criteria is not met.

HIGH QUALITY TRANSIT AREAS (HQTA) SCREENING
Projects located within a Transit Priority Area (TPA) (i.e., within ½ mile of an existing “major transit stop”3 or an existing stop along a “high-quality transit corridor”4) may be presumed to have a less than significant impact absent substantial evidence to the contrary. The Project is not located within ½ mile of an existing major transit stop, or along a high-quality transit corridor.

HQTA screening criteria is not met.

MAP-BASED SCREENING
The County Guidelines note that “residential projects that locate in areas with low VMT, and that incorporate similar features (i.e., density, mix of uses, transit accessibility), will tend to exhibit similarly low VMT.”5 Urban Crossroads has obtained a VMT data table from County Staff for all TAZs within Riverside County that identifies VMT per capita for the purposes of identifying low VMT areas. The data utilizes the sub-regional Riverside Transportation Analysis Model (RIVTAM) to measure baseline VMT performance, and a comparison was made to the applicable impact threshold.

The Project’s TAZ was identified in the Riverside County Transportation Analysis Model (RIVTAM) as TAZ 4787.
1 County Guidelines; Page 19.
2 County Guidelines; Page 42, Table 1
3 Pub. Resources Code, § 21064.3 (“‘Major transit stop’ means a site containing an existing rail transit station, a ferry terminal served by either a bus or rail transit service, or the intersection of two or more major bus routes with a frequency of service interval of 15 minutes or less during the morning and afternoon peak commute periods.”).
4 Pub. Resources Code, § 21155 (“For purposes of this section, a high-quality transit corridor means a corridor with fixed route bus service with service intervals no longer than 15 minutes during peak commute hours.”). 5 Technical Advisory; Page 12

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Coachella City CouncilJanuary 28, 2026

Coachella City Council
January 28, 2026