|
<br />Data Included
<br />
<br />General
<br />
<br />TABLE II-I
<br />
<br />1.
<br />
<br />Design storms for the outfall study hydrology were developed following the
<br />procedures outlined in the Urban Storm Drainage Criteria Manual (USDCM)
<br />(Wright McLaughlin, 1969), The USDCM specifies the temporal distribution
<br />for a 2-hour design storm developed from the I-hour National Oceanic and
<br />Atmospheric Agency (NOAA) precipitation depth. This design storm
<br />approximates a maximum runoff rate from a catchment area of less than 5
<br />square miles in the Denver region. No areal adjustment of the NOAA point
<br />precipitation depth is required for catchments of this size. Design storms were
<br />developed in this manner for the 2-, 5-, 10-, and lOG-year frequencies and are
<br />presented in Table II-I of the document, These design storms were identical
<br />to those used in the Westminster Flood Hazard Area Delineation (FHAD)
<br />hydrologic modelling,
<br />
<br />DESIGN RAINFALLl
<br />
<br />2, CUHP /SWMM input parameters and output flows and storage volumes are
<br />listed in the Technical Appendix of the document for the 2- and 100-year
<br />design storms,
<br />
<br />..'....'..... ,'I'Il-ne. Fro';' ..',. , '.,..,................'....'.'.'..."'.,.,..'.',',',.," ,,',. .'.'.,'.. .'..'. ..,'...,','.>'...., ....."..... i, .'.'.,.,.
<br />.',...."',.~..Dlng of.,.. .>.>....".' . IuCftDleatollJtiptll(l.r. ii .'....'. .i
<br />...'....',.,..""> ,',.'....,' ..... '.
<br />,'.' "shmll,.",. ...,.'.'. "'.'.,,,'. .',,',,' .'~~,,_..',..,.'... ..'.
<br />,.,.,..,.,.,.",',.,.,'.,", <iniiiutesl ,." ,"." '.... 2-Yeai' SOY..... ",.II-y.,....
<br />"",...".." """ '," FreijUendeS" ,,' ."..,>.~ F."Dd ,',.
<br />,.,,",.',,".','. "....,.,'..FrelJUenel!ill , ,..,,"~,ts ,,'
<br />5 ,02 .03 ,03 ,03
<br />10 ,04 ,05 ,06 ,08
<br />15 ,08 .12 ,14 ,12
<br />20 ,16 ,21 ,25 ,21
<br />25 ,25 .35 .42 .38
<br />30 ,14 ,18 ,20 .67
<br />35 ,06 ,08 ,09 .38
<br />40 ,05 ,06 .07 .21
<br />45 ,03 ,05 ,06 ,17
<br />50 ,03 ,05 ,05 ,13
<br />55 ,03 ,04 ,05 ,11
<br />60 ,03 ,04 ,05 ,11
<br />65 ,03 ,04 ,05 .11
<br />70 ,02 ,04 ,05 ,05
<br />75 ,02 .04 ,05 ,05
<br />80 ,02 .03 ,04 ,03
<br />85 ,02 ,03 ,03 ,03
<br />90 ,02 ,03 ,03 ,03
<br />95 ,02 ,03 ,03 ,03
<br />100 ,02 ,02 ,03 ,03
<br />105 ,02 ,02 ,03 ,03
<br />110 ,02 ,02 ,03 ,03
<br /> 115 ,01 ,02 ,03 ,03
<br /> 120 ,01 ,02 ,02 ,03
<br />, ",',. ,',',' " ,. ',',",' ".'," ~ ""'..."".'.,.,.....'....'.""",'.
<br />TOTAL 1.15 1.60 , 1.8!l " ',,' ;J.Oll" '.',
<br />
<br />3, Peak discharges from Great Western Reservoir are 80 cfs for the 2-year storm
<br />and 1,940 cfs for the l00-year storm, Peak discharges from Standley Lake are
<br />60 cfs for the 2-year storm and 1,470 cfs for the 100-year storm,
<br />
<br />4, Table II-I of the document, presented herein, presents the sub-basins with the
<br />CUHP /SWMM model elements, Line diagrams for the models are included
<br />in the Technical Appendix.
<br />
<br />1. This report presents fully approved hydrology for Walnut Creek and Big Dry
<br />Creek downstream of Great Western Reservoir and Standley Lake, New
<br />hydrologic studies should be consistent with this report unless changes are
<br />coordinated fully with UDFCD,
<br />
<br />2.
<br />
<br />The 1986 Technical Appendix (10/15/86 computer runs) indicates that the
<br />100-year inflow flood to Great Western Reservoir is the same as the 100-year
<br />outflow flood of 1940 cfs, It would appear that surface detention storage was
<br />not considered, II
<br />
<br />I Taken from "Outfall Systems Planning" (Muller Engineering, 1987),
<br />
<br />
|