Page 42 - _ 180314 Special Yucaipa GSA Packet

Request for Proposals
Infiltration Testing Implementation for
Thirteen Sites in Yucaipa Basin Area
Yucaipa Basin Recharge Study
Page 2

City of Yucaipa. Figure 2 shows the six sites not under the jurisdiction of SBCFCD. These
six sites are owned by the City of Yucaipa, South Mountain Water Company, and private
individuals.

Impacted waterways include storm channels and storm detention basins along Oak Glen
Creek, Wilson Creek, Yucaipa Creek and Wildwood Creek. As shown in the upper
portion of Table 1, seven sites are existing flood control facilities under the jurisdiction
of SBCFCD. Valley District has obtained the environmental permits needed to conduct
the recharge testing. The sites under the jurisdiction of SBCFCD are currently pending
review at the time of this writing, however all necessary documents have been
submitted in order to obtain a permit from them.

Proposed Infiltration Testing

Each infiltration test will involve the construction of a temporary test infiltration basin,
addition of water into the test basin, and monitoring of water volume added and
ponded water height over an approximately 14-day period. Each test infiltration basin
will have dimensions of approximately 30’ x 30’ x 5’ deep. Each test infiltration basin will
be constructed using a backhoe and will involve soil excavation/management and
potential onsite storage of water used for testing depending on the availability of
preferred water sources. Test monitoring equipment includes a totalizing flowmeter
connected to the hose bib at the water source, a water hose between the water source

and the test infiltration pit, and a staff gage in the basin to allow for measurement of
ponded water depth. During testing, the site needs to be secured with temporary
construction fencing to ensure public safety and to prevent vandalism. The individual
site maps on Figures 1 and 2 show the proposed areas of soil disturbance, including
anticipated limits of the proposed test basin and site access routes for the backhoe.

Management of Excavated Soils
The bottom of each test basin will be excavated 5 feet below existing grade. Excavated

material may be either a) stockpiled adjacent to the test pit above the storm
channel/basin banks or b) if temporary storage of excavated soil within the channel is
acceptable, the excavated soil could be used to create shallow berms around the test
basin. At the completion of infiltration testing, each test basin would be backfilled with
the native excavated material, and the site would be returned to its original, pre-

Yucaipa Groundwater Sustainability Agency - March 14, 2018 - Page 42 of 226