FLOOD05773

• County: Larimer
• Community: Larimer County
• Stream Name: Cooper Slough
• Basin: South Platte
• Title: Hydrologic Analysis of Cooper Slough
• Date: 7/1/1993
• Prepared For: Larimer County
• Prepared By: Love & Associates, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

COOPER SLOUGH HYDROLOGY

BOXELDER OVERFLOW OF INTERSTATE 25 AT STATE HWY 14

MEDIAN CHANNEL FLOW @ ROAD OVERTOPPPING:
AREA, fI2 = 53.58
WET. PER., ft = 44,2
Mannlngs 'n' = 0.04
Slope, fI/fl = 0.0073
FLOW, cis = 193.9

ROAD WEIR 1 :
LENGTH,L =
.C.=

116
2.65

ROAD WEIR 2 :
SLOPE, Z =
LENGTH, L =
.C.=

180
varies
2.65

ROAD MEDIAN FLOW (not to Cooper Slough) WEIR 1 WEIR2 WEIR 2 TOTAL FLOW FLOW TO
OVERTOP AREA WET, PER HYD.RAD Q* head overflow length overflow FROM BOXELDE COOPER
ELEV (ft2) (ft) eft) lets) (ft) (cis) (It) IcIs) (cis) lets)
4935.1 53.58 44.2 1.21 193.9 0.0 0.0 0 0.0 193.9 0.0
4935.2 57.98 44.4 1.31 220.5 0.1 9.7 18 0.6 23O.B 10.3
275.. 29**
4935.3 62.38 44.6 1,40 248.3 0.2 27.5 36 3.4 279.2 30.9
4935.4 66.78 44.8 1.49 277.3 0.3 50.5 54 9.4 337.3 59.9
4935.5 71.18 45.0 1.58 307.6 0.4 77.8 72 19.3 404.6 97.1
4935.6 75.58 45.2 1.67 338.9 0.5 108.7 90 33.7 4Bl.3 142.4
530** 173*.
4935.7 79,98 45.4 1.76 371.3 0.6 142.9 108 53.2 587.4 196.1
4935,8 84.38 45,6 1.85 404.8 0.7 180,0 126 78.2 663.0 258,3
, ., 726** , 301** ,
. . . .
. 4935.9 . , .
88.78 45.8 1.94 439.3 0.8 220.0 144 109.2 768.5 329.2
4936.0 93.18 46.0 2.03 474.8 0.9 262.5 162 146.6 883.9 409.1
4936.1 97.58 46.2 2.11 511.3 1.0 307.4 180 190.B 1009.5 498.2
1136** 590**
4936.2 101.98 46.4 2.20 548.7 1.1 3~.61 198 I 242.1 1145.5 I 596.8 I

4936.3 I
4936.4

106,38 I
110.78

2,37

1.2
1.3

404.1
455.6

301,0 I
367.7

1292,1 I
1449.5

705.1 I
823.3

* Determined by manning's equallon.
** Total Flow from Saxelder values from Gerald SchultzjUSBR study (Refs, 2 and 3). Total flow to Cooper Slough interpolated from spreadsheet.