HomeMy WebLinkAboutDrainage Reports - 03/16/2012 (2)Final Drainage Report
Colorado Iron & Metal
CALCULATION OF A PEAK RUNOFF USING RATIONAL IETHOO
Project THIG CM
Catchment ID: Basin A, 100-year Discharge
1. Catchment Hydrologic Data
Catchment ID = A
Area = 3.18 Acres
Percent Imperviousness= B6.00 %
NRCS SoilType= BA, B, C. or
j O. Rainfall Information I(IncNFr)= C1 I P11(C2• Tdr C3
�\ Design Storm Return Period, Tr=
100 years (input return period fordesign storm>
C1=
2850 ( nput the valu a of C 11
C2=
10.00 (Input the Yalu a of C 2)
C3=
0.793 (input the value of C 3)
P1=
2.91 inches (input one-hr preapaahon—see Sheet "Design Ink"
8L Analysis of Flow Time(rimeof Concentration) fora Catchment
Runoff Coefhciern, C =
0.76
Ovende Runoff Coefficient, C =
(enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient. C c =
0.67
_- Overide 5-yr. Runoff Coefficient. C =
arter an ovende C-5 value ifdesired, or leave blank to accept calculated C-5. )
ttlustratkm
rV.
Rexh 1 Dsv
Huh ` .1 L7 SeZiw�
_ Flan- Dirrrtia.
Caartuwewl
anaaLes
40---S Land
Hevy
Tillage
Shut
Newt
Grassed
Pwmd Pressa
Type
frkadvv
11
�ieki
Pastor.
Dwe
Swales
Shalkw P�Swdes
LLrrs
Ground
Ni sterwa
(Shed�
.roe
2
5
7
10
15-1
�Flan
t—
Calculations:
Reach
Sim"
Length
5-yr
NRCS
Flow
Flea'
ID
5
L
Runoff
cmvey-
Veksdy
Tare
Codl
arsrs
V
Tf
Poa
It
cz
fm
minutes
input
input
output
input
output
cutpui
Overland
0.0200
25
0.67
0.13
3.09
1
0.0050
540
20.00
1,41
6.3E
2
3
4
5
Sum
565
C omputed
Tc =
9 4c
Regional Tc= 13.14
Peak Runoff Prediction using Computed Tc Kliction using Regional Tc
Rainfall Intensity at Tc. 1= 7.88 in dtlltr Rainfall lntensityatTc, l= 6.87 inchhtr
Peak Flovrate, Op= 19.10 cfs Peek Flovaate, Op= 16.64 cfs
UD Rational- Basin A 100yr.)ds, Tc and PeakO
4202011. 10:D7 AM