HomeMy WebLinkAboutDay, Etiwanda and San Sevaine Creek With the exception of the Day Creek Basin immediately south of
Highland Avenue, basin storage of flood flows was not considered
for the ultimate design on the Day Creek Channel System. Wine -
ville and Riverside Basins will be used to some degree for flood
flow storage in the early phases of channel construction.
In the San Sevaine Creek Channel System, the Lower San Sevaine
Basin and Jurupa Basin were used as flood storage basins. Lower
San Sevaine Basin is designed as a flow- through basin and Jurupa
Basin is designed as a by -pass system. Design flows were reduced
below these basins based on analysis and coordination with the
San Bernardino County Flood Control District, and the Riverside
County Flood Control and Water Conservation District.
Tabulation of channel design flows by reach for each system are
given in Section II. The Drainage Plan and hydrology map show
the watershed area, design flows, and basin storage values. Figure
No. 1 shows schematically the location of the proposed basins.
HYDRAULIC DESIGN CRITERIA
The design flow for the flood control systems described herein
is based on a 100 -year frequency storm. The hydraulic design
criteria is described in detail in Section III. In general,
hydraulic methods and design criteria used in developing the
preliminary plans were based on the Los Angeles County Flood
Control District's experiences and practices, and is recommended
herein. Water surface profile calculations for final design
plans should be calculated using the Bernovilli energy equation
combined with the momentum equation for analyzing confluences
and junctions.
A three foot (3') freeboard was used for the channel design where
the flow velocity was 35 feet per second or more. A two foot (2')
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3. UNIT - HYDROGRAPH PEAK FLOW RATES
For ready reference, the peak flow rate estimates at certain
selected points are tabulated below. The design flow is based
on a 100 -year frequency, 24 -hour storm.
Table No. 1
DAY CREEK SYSTEM
Watershed
Location Design Flow
Point General 24 -hour Storm
Number * Description Q100 (cfs) **
1 Day Creek Canyon Mouth 5,310
2 Highland Avenue 6,214
3 Devore Freeway 7,375
4 San Bernardino Freeway 8,156
6 Wineville Basin 9,260
8 Riverside Basin 9,718
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FIGURE 8. OCEMA CRITICAL STORM PATTERN AS A FUNCTION OF WATERSHED AREA