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<br />2. DOUGLAS CREEK SOUTH
<br />
<br />2.1. Watershed Description
<br />
<br />Douglas Creek South (DCS) drains an area in and adjacent to northwestern Colorado Springs
<br />(Figure 2,1), The uppermost portion of the basin reaches on elevation of 8,000 ft, msl, and is within
<br />the Pike National Forest The channel flows generally southeast through industrial and residential
<br />developments for approximately three miles to the confluence with Monument Creek, The outlet is
<br />at an elevation of approximately 6,100 ft, msL
<br />
<br />The total basin area is 3,53 square miles, Hillslope gradients range from 15 to 50 percent in
<br />the upper basin and from 5 to 30 percent in the lower basin, Channel gradients range from 10 to 30
<br />percent in the upper basin, The lower basin channels are predominantly concrete lined with frequent
<br />drop structures and range in gradient from 1 to 6 percent Soils tend to be in the "A" and "S"
<br />hydrologic soil groups as defined by the SCS with "C" soils being well represented in the middle of the
<br />basin, "D" soils are not common except where significant rock outcrop occurs,
<br />
<br />2.2. Previous Studies
<br />
<br />Two previous studies of the basin hydrology were available for review, These were the FIS -
<br />City of Colorado Springs (Ref. 2,1) and the Douglas Creek Drainage Study (DCDS) (Ref. 2.2), The
<br />FIS hydrology was performed by the U,S, Army Corps of Engineers using TM1 procedures (Ref. 2,3)
<br />combined with synthetic unit hydrograph analysis, This approach tends to result in very generalized
<br />estimates of streamflow when applied to small watersheds, The DCDS used Colorado Springs
<br />drainage criteria and assumed full development within the basin,
<br />
<br />2,1 Resource Consultants & Engineers, Inc,
<br />
<br />
<br />Peak discharges at the outlet are presented in Table 2.1, The DCDS arrived at significantly
<br />lower peak discharges than the FIS, This is expected due to the differences in methodology,
<br />
<br />Table 2,1, Summary of Douglas Creek South Hydrology from Previous Reports,
<br />. n__ ___"".
<br />"_","'"'' ,__n_,____..
<br />."",'.', ,',"..,' ,>~~~R!~9!!~$!!f!!pt~~
<br />A!.'me.'C:Clilfl411!l~...WlII1'.Mo!l~m~ilt.9~k
<br />1 O.y~ar 50~Yililr.'. >100ty~i $PO"yeilr
<br />1,600 3,700 5,000 9,900
<br />3,680
<br />
<br />Report
<br />
<br />Drainage
<br />Area
<br />(square miles)
<br />
<br />FIS
<br />
<br />3,52
<br />
<br />Drainage Study
<br />
<br />3.46
<br />
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