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Infiltration Test Results

A B

E

D

A. 4" fire hose / YVWD fire hydrant in background
B. Bermed (background) and Excavated Basin (foreground)
C. Fine silt/clay on ground surface F
D. Post-excavtion and plastic sheeting bermed basin
E. Testing in progress (Day 1)
F. Leaked recharge water east of test basin (Day 6)
C

Conclusions:
- Results of infiltration testing of the bermed basin at Oak Glen Creek indicates that while the site is
favorable for recharge, fine grained sediment in the upper approximately 3 feet of soil has decreased
Test Start Sep-17-2018
the recharge capacity of the basin significantly.
Test End Oct-01-2018 - Clean full-scale basin initial infiltration rates (based on 50% of measured field-scale testing infiltration
Basin Dimensions (L x W) (ft) 34 x 34 rates of the excavated test basin) are estimated at 10.5 feet/day.
Average Water Height (ft) 1.6 YVWD - Long-term infiltration rates (based on 50% of full-scale basin initial infiltration rates) are estimated
2
Infiltrating Area Basin Bottom (ft ) 960 Hydrant at 5.2 feet/day. Long-term rates assume a consistent basin maintenance and cleaning program.
- An estimated full-scale long-term infiltration rate of 2.8 feet/day is predicted, which is similar to
2
Infiltrating Area Basin Bottom + Walls (ft ) 1,270 infiltration rates (3.2 feet/day) measured during pilot testing in 2018.
Oak Glen Creek Basins (City of Yucaipa, Oak Glen Creek Recharge Report, 2018)
Total Water Added (gallons) 639,130 Test Site (Bermed)
Total Water Added (acre-feet) 2.0 X Y Boring EX-2 Recommendations:
" )
High (ft/d) 6.12 - Infiltration test results for excavated and bermed test basins within Oak Glen Creek Basin highlight
Infiltration Rate the effect that the upper 3 feet of accumulated fine silt/clay has on basin infiltration capacity.
Low (ft/d) 5.15
(Constant-Head) - If site recharge goals are expected to exceed the operational capacity of the Oak Glen Creek Basins,
Average (ft/d) 5.6 the removal of the upper 3 feet of sediment in each of the Oak Glen Creek basins prior to future
Infiltration Rate High (ft/d) 6.58 active recharge is recommended. Pilot-scale testing is not critical at this site.
(Falling-Head) Low (ft/d) 5.17 ´
Full-Scale Basin Est. Initial Infiltration Rate (ft/d) 2.8 0 400 Feet Figure 12
Full-Scale Basin Est. Long-Term Infiltration Rate (ft/d) ***2.8 Oak Glen Creek
Basins (Bermed)
*** Initial and long-term infiltration rates are the same, because the basin is already significantly clogged from lack of maintenance
Yucaipa Sustainable Groundwater Management Agency - January 23, 2019 - Page 56 of 137