La Quinta Resort & Club Surface Drainage MaintenanceSeptember 26, 2016
Prepared by
GeoKinetics
Geotechnical & Environmental
Engineers
77 Bunsen
Irvine, CA 92618
Tel 949.502.5353, Fax 949.502.5354
GeoKinetics
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Hydrology and Hydraulics Report
for Surface Drainage Maintenance
and Improvements at
La Quinta Resort & Club
La Quinta, California
Prepared for
Glaser Weil Fink Howard Avchen & Shapiro LLP
Table 1 - Summary of Tributary Area Sizes and Estimated Flow Rates
Page 1 of 1
Tributary
Area Size
Peak Run-Off for Tributary
Area
(CFS)
Run-Off Rate Into Golf Course
Channel Accounting for Time Lag
(CFS)
Peak Cumulative Flow in Golf
Course Channel Without Basin
(CFS)
Peak Cumulative Flow In Golf
Course Channel With Basin
(CFS)
1 65 Acres 227 227 227 227
2 5 Acres 17 17 244 244
3 330 Acres 1,150 1,150 / 1538 1,394 782
4 11 Acres 38 234 1,428 816
5 264 Acres 921 3553 1,981 1,369
6 10 Acres 35 321 2,002 1,390
7 45 Acres 157 477 2,079 1,467
8 40 Acres 140 559 2,138 1,526
1
2
3
4
5
Peak flow occurs ≈ 1.2 minutes prior to arrival of peak flow from Area #'s 1, 2, and 3. Apply correction factor of 0.89 to adjust peak flow per
hydrograph based upon time offset
Peak flow occurs ≈ 4.4 minutes prior to arrival of peak flow from Area #'s 1, 2, and 3. Apply correction factor of 0.60 to adjust peak flow per
hydrograph based upon time offset
Peak flow occurs ≈ 6.4 minutes prior to arrival of peak flow from Area #'s 1, 2, and 3. Apply correction factor of 0.49 to adjust peak flow per
hydrograph based upon time offset
Peak flow occurs ≈8.6 minutes prior to arrival of peak flow from Area #'s 1, 2, and 3. Apply correction factor of 0.42 to adjust peak flow per
hydrograph based upon time offset
Peak flow reduced by detention basin.
Table 2 - Summary of Calculated Flow Conditions
Page 1 of 2
Channel New Basin Bulked Flow Section Flow Rate
(CFS)
Maximum Flow Depth
(Feet)
Water Elevation
(Feet)
Average Velocity
(FPS)
B 1394 5.99 57.89 12.40
C 1394 6.29 57.59 4.30
D 1394 8.10 57.50 2.60
E 1428 7.05 57.45 5.80
F 1428 6.80 57.10 8.80
G 2002 7.69 56.09 9.30
H 2002 7.18 54.78 8.90
I 2079 6.84 53.54 8.80
J 2079 4.90 50.90 5.20
K 2138 5.15 50.25 15.50
B 1394 6.88 58.79 10.20
C 1394 7.22 58.52 3.50
D 1394 9.05 58.45 2.00
E 1428 8.00 58.40 4.80
F 1428 7.80 58.10 7.10
G 2002 8.79 57.19 7.40
H 2002 8.45 56.05 7.10
I 2079 7.92 54.62 6.90
J 2079 5.67 51.67 4.20
K 2138 5.89 50.99 12.20
B 782 4.53 56.43 10.53
C 782 4.84 56.14 3.63
D 782 6.65 56.05 2.19
E 816 5.60 56.00 4.60
F 816 5.43 55.73 7.08
G 1390 6.61 55.01 8.37
H 1390 6.11 53.71 7.74
I 1467 5.91 52.61 7.73
J 1467 4.27 50.27 4.75
K 1526 4.27 49.57 13.75
B 782 5.24 57.14 8.61
C 782 5.59 56.89 2.89
D 782 7.43 56.83 1.75
E 816 6.38 56.78 3.81
F 816 6.25 56.55 5.81
G 1390 7.49 55.89 6.79
H 1390 7.14 54.74 6.25
I 1467 6.84 53.54 6.22
J 1467 4.95 50.95 3.62
K 1526 5.24 50.34 10.77
Existing
No
No
Yes
(10%)
No
Yes
Yes
(10%)
Table 2 - Summary of Calculated Flow Conditions
Page 2 of 2
Channel New Basin Bulked Flow Section Flow Rate
(CFS)
Maximum Flow Depth
(Feet)
Water Elevation
(Feet)
Average Velocity
(FPS)
B 1394 5.75 55.67 9.56
C 1394 5.65 55.50 6.17
D 1394 5.63 55.28 5.23
E 1428 5.63 54.95 6.42
F 1428 5.63 54.46 6.58
G 2002 5.58 53.98 8.59
H 2002 5.29 52.99 7.19
I 2079 5.42 52.12 7.59
J 2079 4.16 50.16 5.71
K 2138 4.13 49.23 13.97
B 1394 6.37 56.29 8.34
C 1394 6.27 56.12 5.36
D 1394 6.24 55.89 4.32
E 1428 6.27 55.59 5.58
F 1428 6.28 55.11 5.71
G 2002 6.24 54.64 7.38
H 2002 6.02 53.72 5.34
I 2079 6.35 53.05 6.12
J 2079 4.97 50.97 4.41
K 2138 5.06 50.16 11.03
B 782 4.49 54.41 7.41
C 782 4.42 54.27 4.89
D 782 4.45 54.10 4.45
E 816 4.48 53.80 4.89
F 816 4.61 53.44 4.85
G 1390 0.71 53.11 7.45
H 1390 4.53 52.23 6.44
I 1467 4.61 51.31 6.59
J 1467 3.54 49.54 5.22
K 1526 3.39 48.49 12.59
B 782 5.07 54.99 6.43
C 782 5.01 54.86 4.14
D 782 0.05 54.70 3.68
E 816 5.11 54.43 4.2
F 816 5.26 54.09 4.15
G 1390 5.39 53.79 6.28
H 1390 5.27 52.97 5.07
I 1467 5.40 52.10 5.39
J 1467 4.16 50.16 4.05
K 1526 4.14 49.24 9.99
Improved
No
No
Yes
(10%)
Yes
No
Yes
(10%)
SEDIMENT/DEBRIS BULKING FACTORS
AND POST-FIRE HYDROLOGY
FOR VENTURA COUNTY
FINAL REPORT
June 2011
Prepared for: Prepared by:
Ventura County
Watershed Protection District
WEST Consultants, Inc.
San Diego, California
WEST Consultants, Inc. Ventura County Bulking Study
June 2011 Final Report 4-4
4.3.2 Manning’s n Coefficients
To model hyperconcentrated flow, Manning’s n values should be adjusted as follows (Appendix A):
Manning’s n (laminar flows, Re < 500):
0.74 /bulked bulkednq (English units only) (4.2)
Manning’s n (turbulent flows, Re > 500):
1/9
bulked
bulkednn
(4.3)
where:
V = flow velocity (ft/sec)
y = depth of flow in the channel (ft)
q = is the bulked flow per linear foot width of the channel (ft2/sec)
Re bulkedVy/4 = Reynolds number (dimensionless)
To test the use of the Manning’s n equation for bulked, turbulent flows, an HEC-RAS hydraulic
model for Pole Creek was used as an example. The Reynolds number ranged from approximately
800 to 2,400 (depending on the peak discharge and cross section), which corresponds to the
turbulent flow threshold of approximately 500 cfs (using νbulked = 0.282 ft2/s).
Table 4-2 shows computed nbulked values for a range of sediment concentrations by volume. As
sediment concentration by volume and clear water Manning’s n increase, Manning’s nbulked increases,
which indicates that higher n values are required to represent sediment-laden flows.
Table 4-2. Computed Manning’s n for Bulked Flows – Pole Creek Example (Turbulent Flow)
Sediment
Concentration
(% by Volume)
Manning's n
0 0.015 0.02 0.025 0.03
10 0.018 0.024 0.030 0.036
20 0.023 0.030 0.038 0.045
30 0.029 0.039 0.048 0.058
40 0.035 0.047 0.059 0.071
50 0.045 0.060 0.075 0.090