HomeMy WebLinkAboutSite Certifications - 06/17/20041630 S. college rflr"W
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(970) 493-2802
57,4X (970) 495- 9735
June 17, 2004
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, CO 80526
Attention: Mr. Basil Hamdam
RE: Drainage Swale between Mountain Ridge Farms 2nd Filing and Cobblestone Corner PUD, Fort Collins,
CO
Dear Basil:
We calculated the 100 year flow to 3 design points along the western property line of Cobblestone Comer
PUD and the corresponding depth of flow within the channel. We used the c values from the approved Final
Drainage Study for Mountain Ridge Farms 2"d Filing. We calculated the time of concentration assuming a
channel velocity of 1.0 fps. From our calculations, the actual velocities are less than 1.0 fps which would
result in a longer time of concentration and a lower flow rate. Therefore, we believe that our flow
calculations are conservative.
Our channel hydraulics were based on an "n" value of 0.060. The bottom of the channel is a concrete pan
with a much lower `W' value. If we were to average the "n" value, we would get a lower `W' value and a
smaller depth of flow. We also used 4:1 side slopes in our calculations. We believe that our assumption will
result in a calculated depth that is greater than the actual flow depth during a 100 year event.
Our results show that the worst case occurs at design point 7A, which is the farthest north design point. In
the worst case, there would be a depth of flow of 0.56 feet or approximately 6 1/4 inches at the property line.
With an assumed 10:1 slope, the width of flow on Cobblestone Corner will be approximately 5.6 feet, which
is well within the existing 10 foot drainage easement adjacent to Cobblestone Corner's property line. We
also calculated the depth with a 5 percent side slope on one side and 4:1 on the other side. The result was a
flow depth of 0.49 feet with a depth of 0.40 feet at the property line. With a 5 percent slope, the width of
flow on Cobblestone Corner will be approximately 8.0 feet.
The middle design point has a smaller impact on Cobblestone Corner and the southern design point had no
impact on Cobblestone Comer. Please refer to our attached calculations for additional information.
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contact me at the above address or phone number.
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/3,eE.-q = 4. 67. �o ly�o zZ = /, 03/9Lc cuoo = a Si
DESCRIPTION
TRAPEZOIDAL CHANNEL ANALYSIS Lff 1 �' Q S'Po SGof��S
NORMAL DEPTH COMPUTATION
June 17, 2004
- ------------------------------------------
PROGRAM INPUT DATA
VALUE
--------------------------------------------------------------------------------
Flow Rate(cfs)............................................. 2.43 OR"-- 4/ov
Channel Bottom Slope(ft/ft)................................ 0.0039
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 4.0 wa-
Channel Right Side Slope (horizontal/vertical).............. 20.0 O&�
Channel Bottom Width(ft)................................... 2.0
-------------------
-------------------
COMPUTATION RESULTS
DESCRIPTION VALUE
Normal Depth(ft)........................................... 0.48 6� OFPr�
Flow Velocity (fps) ................................ ......• 0.65
Froude Number ............................................... 0.22
Velocity Head(ft).......................................... 0.01
Energy Head(ft)............................................ 0.49
Cross -Sectional Area of Flow (sq ft).. ...............•••••• 3.72
Top Width of Flow(ft)••••••••••••••••........ ••............ 13.51
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson & Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
TRAPEZOIDAL CHANNEL ANALYSIS
NORMAL DEPTH COMPUTATION
June 17, 2004
PROGRAM INPUT DATA
�/ : / Siva Sip
DESCRIPTION VALUE
Flow Rate(cfs)............................................. 2.43 •E-- Qlac,
Channel Bottom Slope(ft/ft)................................ 0.0039
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 4.0 e'--
Channel Right Side Slope (horizontal/vertical).............. 4.0 `—
Channel Bottom Width(ft)................................... 2.0
- - -------------------
COMPUTATION RESULTS
DESCRIPTION VALUE
-------------------------------------------------------------------------------
Normal Depth(ft)........................................... 0.64 4
Flow Velocity (fps) ....................................••••• 0.84
Froude Number ............................................... 0.231
Velocity Head(ft)....................................•••••• 0.01
Energy Head(ft)............................................ 0.65
Cross -Sectional Area of Flow (sq ft)..................•••••• 2.9
Top Width of Flow(ft)....................................•• 7.1
------------------------------------------------------------------
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson & Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
�KI_V77-4-1/ OC7jFP7-H pG C,0�69.v,LJ,.FL Q Tc ' 93,6 / -
DO_4-�7-W G,,r- I-&/AV-T�-sP (E = 0.6Y' - 0-via= 0. fa �T
/_'ZcIC-�T:;; --A� .�iors� Z �" o
TRAPEZOIDAL CHANNEL ANALYSIS
NORMAL DEPTH COMPUTATION
June 17, 2004
------------------
------------------
PROGRAM INPUT DATA
DESCRIPTION VALUE
---------------------------------------- ---------------------------------------
Flow Rate(cfs)............................................. 2.43 ' Q roU
Channel Bottom Slope(ft/ft)................................ 0.0039
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 10.0 E---
Channel Right Side Slope (horizontal/vertical).............. 4.0 4
Channel Bottom Width(ft)................................... 2.0
DESCRIPTION
--------------------------------------
COMPUTATION RESULTS
VALUE
--------------------------------------------------------------------------------
Normal Depth(ft)........................................... 0.56 4C.06z1.7—
Flow Velocity (fps) ......................................... 0.74
Froude Number ............................................... 0.225
Velocity Head(ft).......................................... 0.01
Energy Head(ft)............................................ 0.57
Cross -Sectional Area of Flow (sq ft).......... I............. 3.29
Top Width of Flow(ft)..................... I................ 9.8
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson s Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
,e�ZE/4`7 /7'
,DEPTH o�
.06
l 7 B
TRAPEZOIDAL CHANNEL ANALYSIS si0� fLO�$
NORMAL DEPTH COMPUTATION 74
June 17, 2004
-----------------------------------------
PROGRAM INPUT DATA
DESCRIPTION VALUE
--------------------------------------------------------------------------------
Flow Rate(cfs)............................................. 2.93
Channel Bottom Slope(ft/ft)................................ 0.0026
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 4.0 ^
Channel Right Side Slope (horizontal/vertical).............. 4.0 �
Channel Bottom Width(ft)................................... 2.0
COMPUTATION RESULTS
DESCRIPTION VALUE
--------------------------------------------------------------------------------
Normal Depth(ft)........................................... 0.76
Flow Velocity (fps) ......................................... 0.76
Froude Number ............................................... 0.194
Velocity Head(ft).......................................... 0.01
Energy Head(ft)............................................ 0.77
Cross -Sectional Area of Flow (sq ft)..................•••••• 3.86
Top Width of Flow(ft)....................................•• 8.11
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson 6 Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
�r-
TRAPEZOIDAL CHANNEL ANALYSIS Gf
NORMAL DEPTH COMPUTATION
June 17, 2004
PROGRAM INPUT DATA
DESCRIPTION VALUE
--------------------------------------------------------------------------------
Flow Rate(cfs)............................................. 2.93 •E--Q,oc
Channel Bottom Slope(ft/ft)................................ 0.0026
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 4.0 �-
Channel Right Side Slope (horizontal/vertical).............. 10.0 L—
Channel Bottom Width(ft)................................... 2.0
COMPUTATION RESULTS
DESCRIPTION VALUE
Normal Depth(ft)........................................... 0.66 DEBT/
Flow Velocity (fps) ......................................... 0.67
Froude Number ............................................... 0.188
Velocity Head(ft).......................................... 0.01
Energy Head(ft)................................... :........ 0.67
Cross -Sectional Area of Flow (sq ft)..................•••••• 4.39
Top Width of Flow(ft)..............................••...•.• 11.27
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson & Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
,6� i 6 77XIllr ,f]6PT.5� OF P'w/I.,t - -c 10 ' ,4 = 93, a Z 9 3, 3/ = 0 3��r
TRAPEZOIDAL CHANNEL ANALYSIS
NORMAL DEPTH COMPUTATION
June 17, 2004
------------------
PROGRAM INPUT DATA
DESCRIPTION VALUE
G/. !/ Sio.� Scos�cGr
Flow Rate (cfs)............................................. 3.78
Channel Bottom Slope(ft/ft)................................ 0.0032
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 4.0
Channel Right Side Slope (horizontal/vertical).............. 4.0 �^
Channel Bottom Width(ft)................................... 2.0
----------------------------------------
COMPUTATION RESULTS
DESCRIPTION VALUE
--------------------------------------------------------------------------------
Normal Depth(ft)........................................... 0.82
Flow Velocity (fps) ......................................... 0.87
Froude Number ............................................... 0.217
Velocity Head(ft)....................................•••••• 0.01
Energy Head(ft)............................................ 0.83
Cross -Sectional Area of Flow (sq ft)..................•••••• 4.32
Top Width of Flow(ft)....................................•• 8.55
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson s Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
• �FS//9.ti/ Pin.rT %G
TRAPEZOIDAL CHANNEL ANALYSIS
NORMAL DEPTH COMPUTATION
June 17, 2004
------------------
------------------
PROGRAM INPUT DATA
DESCRIPTION VALUE
Flow Rate(cfs)............................................. 3.78 Qlotl
Channel Bottom Slope(ft/ft)................................ 0.0032
Manning's Roughness Coefficient (n-value)................... 0.06
Channel Left Side Slope (horizontal/vertical)............... 10.0 �-
Channel Right Side Slope (horizontal/vertical).............. 4.0 �-
Channel Bottom Width(ft)................................... 2.0
COMPUTATION RESULTS
DESCRIPTION VALUE
--------------------------------------------------------------------------------
Normal Depth(ft)........................................... 0.71 tc — OEPT/i
Flow Velocity (fps) ......................................... 0.77
Froude Number ............................................... 0.212
Velocity Head(ft).......................................... 0.01
Energy Head(ft)............................................ 0.72
Cross -Sectional Area of Flow (sq ft)..................•••••• 4.9
Top Width of Flow (ft)....................................... 11.88
HYDROCALC Hydraulics for Windows, Version 1.0 Copyright (c) 1996
Dodson 5 Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069
Phone:(281)440-3787, Fax:(281)440-4742, Email:software@dodson-hydro.com
All Rights Reserved.
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