Page 52 - Yucaipa Sustainable Groundwater Management Agency - Yucaipa SGMA

Infiltration Test Results Dunlap

Channel
Site

CLAY
Note: Flow rates into the basin averaged 0.3 to 0.7 gpm
(below minimum threshold of digital paddle meter); B
thus infiltration rates were calculated based on A
meter readings approximately every one to three days.

F

A. WHWC hydrant setup on Avenue D
D B. Excavation of test infiltration basin
C. Native clay sediment deposited on base of
flow control skid at end of testing (Day 13)
D. Testing in progress (Day 1)
E. End of falling-head test (Day 13)
F. Geologic cross section 2-2' (Figure 5b;
Geoscience, Dec 2014) showing
significant clay lenses in vadose zone
beneath Dunlap Channel test basin site

C E

Test Start Jul-16-2018
Conclusions:
Test End Jul-30-2018
- Results of infiltration testing indicate that the site is not suitable for recharge.
Basin Dimensions (L x W) (ft) 33 x 30 - Full-scale basin initial infiltration rates (based on 50% of measured field-scale testing infiltration
Average Water Height (ft) 2.5 rates) are estimated at 0.1 feet/day. Long-term infiltration rates (based on 50% of full-scale basin
initial infiltration rates) are estimated at <0.1 feet/day.
2
Infiltrating Area Basin Bottom (ft ) 960
2
Infiltrating Area Basin Bottom + Walls (ft ) 1,270 Dunlap Channel Recommendations:
Total Water Added (gallons) 22,895 Test Site - Regional geologic cross sections and interpretations indicate vadose zone sediments are comprised
of significant fine-grained clay layers in this area of the Western Heights Subarea, corresponding
Total Water Added (acre-feet) 0.1 with the very low infiltration rates observed during testing.
High (ft/d) 0.14 " ) - No additional actions are recommended at this site.
Infiltration Rate
Low (ft/d) 0.1
(Constant-Head)
Average (ft/d) 0.1
Infiltration Rate High (ft/d) 0.19
(Falling-Head) Low (ft/d) 0.18 ´ Figure 3
Full-Scale Basin Est. Initial Infiltration Rate (ft/d) 0.1 0 800 Feet Dunlap
Full-Scale Basin Est. Long-Term Infiltration Rate (ft/d) 0.0 Channel

Yucaipa Sustainable Groundwater Management Agency - January 23, 2019 - Page 47 of 137