FLOOD04641

• County: Denver
• Community: All
• Stream Name: All
• Basin: South Platte
• Title: Proposed Hydrology for use in Hydraulic Analysis of FEMA Flood Studies and Restudies
• Date: 9/1/1989
• Prepared For: State of Colorado
• Prepared By: Resource Consultants
• Floodplain - Doc Type: Educational/Technical/Reference Information

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subbasin 3 on Figure 2.1, collects at the Patty Jewett Pond via
a storm sewer system. This structure serves to regulate the
sigllificant flow from this area before passing it on to the
South Shooks Run Channel.

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2.2

Previous Studies

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Two previous studies of the basin were available for review.
These w,ore the FIS .:. Cill of Colorado Spring1l. (Reference 6)
and the Shooks Run Master Draina~ Basin Studv (SIlRMDR)
(Reference 7). The recently completed Lower Craemor Master
Drainaj~ Report (Reference 8) provided background for
evaluatIon of the upper hasin. Plans and discharge curves for
the Patty Jewett Dam were obtained from the State EngIneer's
OffIce. DraInage details for subbasIn 3 came from the Palmer
Park Ma~ DraL~~ Study (Reference 9). In addItIon, much
InformatIon and materials were obtaIned from the CIty of
Colorado SprIngs Department of Public Works.

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RevIew of the two earlier studIes Indicates that both were
conductl!d under the gui de lines of previously specified Colorado
Springs drainage criterIa. The storm parameters used for the
SHRMDR to obtain the JOO-year flood were based on a I-hour
storm duratIon with rainfall intensities of 2.3 inches In the
Shooks Run Channel and 2.0 inches in the tributaries and
subdIvisions under AMC II condItIons. Hydrology for the FIS
was developed by the U. S. Army Corps of EngIneers and Is
presented in a hydrologic report pertainIng to the general
Colorado SprIngs area (Reference 10). The analysis utilized a
synthetic unit hydrograph method which was correlated wi th TM-l
(Reference 11) methods. ThIs approach tends to result In very
generalized estimates of streamflow when applIed to small
watershl!ds.

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TABLE 2.1 _. ~UMMARY QE ~IR PEAK DISCHARGES FROM PREVIQUS REPORTS

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REPORT

DRAINAGE AREA
lli\tare mile!l.L

PEAK DISCHARGES .D::.ful
AT THE CONFLUENCE WITU FOUNTAIN CREEK
10 YR 50 YR 100 YR 500 YR

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FIS
SHRMDR

9.1.
7.3

4,900

6,700

7,800
4,524

11,500

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Peak discharge res\tlts at the confluence with Fountain Creek
are presented in Table 2.1 for the two studies; consIderable
discrepancy In peak discharge values is obvIous. AsIde from
the differences in technical approach, it is difficult to
ascertain exactly how this substantial difference in peak flow
has been established. One may infer that the listed drainage
area of 9.4 square miles from the FIS (as compared to 7.4
square miles and 7.8 square miles for the lower basin
determIned by the SHRMDR and RCI, respectively) may be an
indication that the Van Buren Ditch diversion was neglected in

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R€~OURC€ CON~ULTI\NT~ INC

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