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Infiltration Test Results

A B

E

C

F

DRY SOIL (SILT) A. Initial excavation of test infiltration basin
10-12 FEET BELOW B. 4" fire hose through intra-basin culvert
C. Clay on basin surface from historical SWP recharge
C CHANNEL BOTTOM D operations; SWP water during test release from turnout
D. Fine-grained silt/clay 0-2.5 feet; silt/sand/gravel 2.5-5 feet)
E. Test in progress (Day 11)
F. Dry basin after falling-head test (Day 14)

Conclusions:
Test Start Aug-13-2018 - Results of infiltration testing confirm that the site is suitable for recharge.
Test End Aug-27-2018 - Full-scale basin initial infiltration rates (based on 50% of measured field-scale testing infiltration
Basin Dimensions (L x W) (ft) 32 x 29 rates) are estimated at 3.7 feet/day. Long-term infiltration rates (based on 50% of full-scale basin initial
Average Water Height (ft) 3.0 Chicken Hill Fault YVWD infiltration rates) are estimated at 1.8 feet/day.
- While long-term estimates consider expected clogging of the basin bottom from SWP water,
Hydrant
2
Infiltrating Area Basin Bottom (ft ) 960 actual long-term rates will be dependent on the specific site recharge goal and implementation
2
Infiltrating Area Basin Bottom + Walls (ft ) 1,270 of a basin maintenance plan.
- Declining infiltration rates during the test are associated with shallow recharge mounding
Total Water Added (gallons) 882,120 Wilson Creek Basins identified by the USGS (Mooreland, 1970)
Total Water Added (acre-feet) 2.7 Test Site
High (ft/d) 8.71 " ) Recommendations:
Infiltration Rate - If site recharge goals are expected to exceed the operational capacity of the basins,
Low (ft/d) 6.05 the removal of the approximately upper 3 feet of sediment in each of the basins is
(Constant-Head)
Average (ft/d) 7.4 recommended prior to future active recharge. Pilot-scale testing is not recommended at this site.
Infiltration Rate High (ft/d) 7.39
(Falling-Head) Low (ft/d) 5.51 X Y Exploratory Boring EX-1 ´ 0 400 Feet Figure 7
Full-Scale Basin Est. Initial Infiltration Rate (ft/d) 3.7 Piezometer PZ1 Wilson Creek
Full-Scale Basin Est. Long-Term Infiltration Rate (ft/d) 1.8 Basins

Yucaipa Sustainable Groundwater Management Agency - January 23, 2019 - Page 51 of 137