Page 53 - _ 180314 Special Yucaipa GSA Packet

1. INFILTRATION TESTING WORK PLAN APPROACH

The San Bernardino Valley Municipal Water District (Valley District) has been working
collaboratively with the City of Yucaipa, San Bernardino County Flood Control District
(SBCFCD), and retail water agencies to develop a Groundwater Management Plan (Plan) for
the Yucaipa Basin (Basin). A key objective of the Plan is to manage local groundwater
resources conjunctively with imported State Water Project (SWP) water supplies and to
increase basin recharge with natural storm runoff and recycled water. Valley District and its
partners have completed preliminary field investigations across the Basin and have
identified up to thirteen (13) investigation sites potentially suitable for future recharge
facilities.

To determine whether the permeability of upper vadose zone sediments are favorable for
long‐term groundwater recharge via surface spreading methods, Valley District and its
partner agencies are proposing to conduct a series of short‐term infiltration tests. Test
results will provide a planning‐level estimate of the long‐term infiltration capacity of each
investigation site.

The purpose of this Work Plan is to provide Valley District and its partners the information
needed to (1) prioritize investigation sites for testing, (2) obtain necessary permits from
local, state, and federal regulatory agencies, and (3) prepare and plan for the
implementation of the infiltration tests (tentatively scheduled to commence in late
Summer/early Fall of 2017). The work plan incorporates information collected during a
reconnaissance visit to the thirteen sites on April 27, 2016. The site visit was attended by
representatives from Todd Groundwater (TODD), Valley District, City of Yucaipa, Yucaipa
Valley Water District (YVWD), Western Heights Mutual Water Company (WHMC), South
Mesa Water Company (SMWC), San Bernardino County Flood Control District (SBCFCD), and
the U.S. Geological Survey (USGS). During the site reconnaissance, (1) suitable locations and
dimensions for test infiltration basins and potential water sources were identified at each
site, (2) physical conditions and access routes were confirmed, and (3) site security and
traffic control needs were assessed.

This Work Plan describes the proposed infiltration testing activities, including test basin
locations, preferred sources for test water, equipment needs, soils management associated
with proposed earthwork, security measures, and field monitoring protocol. A preliminary
field schedule and cost estimate is provided to conduct the infiltration tests. Costs include
contractor labor, material costs, and equipment rental fees. Costs are also included for
engineering supervision to manage the field program, evaluate infiltration test results, and
document key findings and recommendations in a final report.

1.1. INVESTIGATION SITES AND IMPACTED WATERWAYS

The thirteen proposed sites include undeveloped parcels, storm channels and basins along
Oak Glen Creek, Wilson Creek, and Yucaipa Creek owned by the San Bernardino County

Final Infiltration Test Work Plan for
Thirteen Investigation Sites
Yucaipa Valley, CA 1 TODD GROUNDWATER

Yucaipa Groundwater Sustainability Agency - March 14, 2018 - Page 53 of 226