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3 | Groundwater Sustainability Plan for the Yucaipa Basin Area | San Bernardino Valley Municipal Water District

project approach

Our approach is designed to efficiently produce a GSP that is defensible and widely accepted. Tasks
1 through 5 are largely informational, and the WSC-Geoscience Team will perform these tasks
efficiently as we will draw on the experience of key team members in the Yucaipa Basin. WSC’s
proven facilitation and stakeholder engagement team will navigate the GSA through critical Tasks
6 ,7, and 9 of the GSP and gain alignment amongst the GSA members. Following each task where a
technical memorandum is prepared, the draft technical memorandum will be reviewed by the GSA,
and a workshop will be conducted and coordinated with the regularly scheduled GSA meetings. In
addition to the workshops with the GSA, 13 workshops with the Technical Advisory Committee (TAC)
will be conducted at strategic junctures during the development of the GSP, as described in Task 17
in the RFP. During preparation of this proposal, our team identified two additional recommended TAC
meetings to address the sustainable yield estimations and definition of management areas that will be
critical for the success of the GSP.

EVALUATE SUPPLIES AND DEMANDS

TASK 1.0 USGS GROUNDWATER MODEL
Our team has successfully used models developed by the USGS to conduct geohydrologic studies in several
groundwater basins, including groundwater models for the San Bernardino Basin Area, Rialto-Colton
Basin, and Antelope Valley. Geoscience is currently in the process of developing an integrated Upper
Santa Ana River groundwater model that incorporates the model layers developed by the USGS in the
Yucaipa Basin.
The Yucaipa Basin Groundwater Model developed by the USGS is a four-layer groundwater model using
the computer code GSFLOW. GSFLOW was developed by the USGS to simulate coupled groundwater
and surface water resources. We have used the GSFLOW computer code to develop the Murrieta-
Temecula Groundwater Basin Model in coordination with the USGS and can conduct the model scenarios
efficiently and accurately for the Yucaipa Basin.
We will obtain the calibrated Yucaipa Groundwater Model developed by the USGS and will rerun the
model to validate the results. Our team will analyze the modeled water budgets to develop the information
required in the following tasks, historic and current groundwater conditions (Task 2), water budget and
sustainable yield (Task 4), and data management system (Task 12). We will also run various predictive
model scenarios to provide necessary information to define undesirable results, minimum thresholds and
measurable objectives (Task 6) and to identify projects and management actions to achieve sustainability.

TAC Meeting: USGS Model Inputs Deliverables: TM summarizing USGS model use for GSP preparation

TASK 2.0 CURRENT AND HISTORICAL GROUNDWATER CONDITIONS

2.1 Summarize Studies
The Yucaipa Groundwater Basin has been studied extensively since the 1970s by the USGS and
consultants working for the Yucaipa Valley Water District or Valley District. Geoscience has reviewed
the geologic and hydrogeologic technical documents available for the basin over the course of a number
of studies completed in the basin.

Yucaipa Sustainable Groundwater Management Agency - August 9, 2018 - Page 7 of 208