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Infiltration Test Results

Note: Flow rates into the basin averaged 7.0 to 7.7 gpm
(below minimum threshold of digital paddle meter); B
thus infiltration rates were calculated based on A
meter readings approximately every two days.

E

A. YVWD hydrant at 10th Street and 4" fire hose
B. 4" fire hose along northern channel bank west of 10th Street
C. Excavated basin, fencing, and soil stockpile
D. Initial test basin filling (Day 1)
C D E. Falling head test in progress view from south (Day 2)

Conclusions:
Test Start Sep-24-2018 - Results of infiltration testing indicate that the site (within the channel) is not suitable for recharge.
- Full-scale basin initial infiltration rates (based on 50% of measured field-scale testing infiltration
Test End Oct-01-2018 ´ 0 400 Feet YVWD Hydrant rates) are estimated at 0.7 feet/day. Long-term infiltration rates (based on 50% of full-scale basin initial
Basin Dimensions (L x W) (ft) 46 x 20 infiltration rates) are estimated at 0.4 feet/day.
Average Water Height (ft) 2.0 - Low infiltration rates appear to be due to low-permeability clayey silt sediments comprising
the channel sidewalls and bottom.
2
Infiltrating Area Basin Bottom (ft ) 960 - Fine-grained deposits were identified in EX-9 from 15 to 25 feet-bgs (approximately 0 to 10 feet
2
Infiltrating Area Basin Bottom + Walls (ft ) 1,270 below the channel bottom); however, fine-grained material also appears to be associated with
sediment load from natural stormflows.
Total Water Added (gallons) 50,632 Boring
Total Water Added (acre-feet) 0.2 X Y EX-9 Recommendations:
High (ft/d) 1.59 - Surficial sediments found Oak Glen Creek at this location are comprised of predominatly
Infiltration Rate fine-grained sediments that may be naturally occurring and also associated with
Low (ft/d) 1.24
(Constant-Head) Oak Glen Creek at Western Heights natural stormflows, which significantly inhibit infiltration.
Average (ft/d) 1.4 - No additional actions are recommended at this site.
Test Site
Infiltration Rate High (ft/d) 1.64 " )
(Falling-Head) Low (ft/d) 1.45 Figure 13
Full-Scale Basin Est. Initial Infiltration Rate (ft/d) 0.7 Oak Glen Creek
Full-Scale Basin Est. Long-Term Infiltration Rate (ft/d) 0.4 at Western Heights

Yucaipa Sustainable Groundwater Management Agency - January 23, 2019 - Page 57 of 137