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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12.2

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through thIs canal and has been Included in the basIn mapping
shown In Figure 12.1.

At Bradley Road (WG-4 on Figure 12.1) the WG channel is
diverted into an underground 12 foot diameter culvert 1,200
feet into a stormwater detention pond (WG-5 on Figure 12.2).
The culverts at Bradley Road restrict the flows and the
embankment has created a detention pond (Pond 4 on Figure
12.1). The lower detention pond (Pond 5 on Figure 12.1)
releases into a channelized portion of WG which flows 2,700
feet in a concrete lined channel section, to another 12 foot
dIameter culvert which then carries WG drainage waters
underground to Fountain Creek.

Several previous studies have been conducted for WG basin.
These ,oonsist of the FIS -=- II Paso County (Reference 19),
Windmill Gulch Master Drainage Study (Reference 24), WindmIll
Gulch ~torm Water Management Plan (Reference 25), and several
other reports dealing with drainage plans for development of
the Fountain Valley Ranch property in the lower portion of the
basin.

Previous Studies

Peak flows for the various hydrologic studies conducted for the
WG basin are summarIzed in Table 12.1. Previous FIS studies
utilized the hydrology that was developed by the U.S. Army
Corps of Engineers (Reference 10) which developed hydrology for
several basIns in the Colorado Springs and El Paso County area.
Thls study (previously discussed under South Shooks Run) was
the bas is for the exis cIng FIRM's for WG. The 100-year peak
flow at the mouth of WG was estimated to be 5,000 cfs for thls
study.

In 1984 the Wlndmlll Gulch Master Dralnagg Study was completed
by Finn and Associates (Reference 24). ThIs study estImated
flows for the basin for exIsting and future development
condltions. It excluded a large portion of the basin above
Drennan Road, claIming that it would not contribute runoff
durlng the 100-year flood. In additIon, the study assumed that
flows in the upper portion of the basin (above Bradley Road)
would bE! captured by Canal #4 and would not contribute flows to
the lower WG channel for floods of the 5-year magnitude or
less.

In December of 1984, LanSer, Inc. prepared the Fountain Valley
Subdivision !2ralnagg Study report (Reference 26), which revised
the previous hydrology but utilized the same general
asslUnptlons of the Finn and Associates Study. In 1985, further
drainage studies were completed for the Fountain Valley Ranch
development by RBD (Reference 27), which utilized the same
hydroloE;y that was presented in the LanSer report.
In 1986, a new Storm Water Management Plan was developed by
Simons, Li and Associates, Inc. (SLA) (Reference 28). This

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