Page 84 - Yucaipa Sustainable Groundwater Management Agency - Yucaipa SGMA
P. 84
The DWR guidance on incorporating climate Task 6. Define Undesirable
change into the assessment of sustainability is
currently limited and the data sets to be used Results, Minimum Thresholds,
for these analyses were not developed Measureable Objectives
specifically to address the 50-year planning
horizon analyzed in the GSP. The DWR data Development of the sustainable management
sets cover a longer time horizon than will be criteria lies at the heart of the GSP. These
simulated for the Basin sustainability analysis, criteria are what provide the GSA with the
leaving the GSA to consider which 50-year operational flexibility to maximize the use of
period(s) to simulate as part of the plan. One groundwater in the Basin while simultaneously
way to address uncertainty in future climate avoiding undesirable results.
conditions is to simulate the future conditions
using a dry, average, and wet 50-year period Undesirable Results
from the data provided by DWR. The GSA must define undesirable results in the
Basin by determining what condition(s) in the
Another way to assess uncertainty is to produce
a range of synthetic future climate data, based Basin would be significant and unreasonable
on the historical distribution of precipitation and for each sustainability indicator. This
the gridded change factors provided by DWR. determination is based on an analysis of how
Dudek will work collaboratively with the GSA to the minimum thresholds may affect the
establish technically sound and locally specific interests of beneficial uses and users of
future conditions to simulate in the Basin. groundwater, or land use and property
interests. Because both beneficial uses and
Results of the numerical model in simulating users of groundwater are considered when
the baseline water budget and future budgets defining undesirable results, the determination
influenced by planned projects and climate of undesirable results must incorporate
change will be documented in the “Water stakeholder feedback. Dudek, with input from
Budget and Sustainable Yield” section of the the TAC, will provide the analysis of the
”Basin Setting” chapter. This chapter will be technical information to support the decision-
developed with input from Valley District, USGS, making process, and will work collaboratively
and the TAC. with the GSA and stakeholders to facilitate the
development of undesirable results.
Task 5. Define Management Areas
Minimum Thresholds
Dudek will work with the GSA, TAC, and USGS to The minimum thresholds are the quantitative
identify and define management areas within measure of undesirable results and are set at
the Basin. The management areas will be individual monitoring sites. These thresholds
based on hydrogeologic data (e.g., faulting that will be established, based on an analysis of how
created hydraulic barriers to groundwater flow) they would impact beneficial uses and users of
and/or jurisdictional boundaries to facilitate groundwater in the Basin and the determination
more effective management of water resources. of undesirable results for each sustainability
Dudek will prepare the “Management Areas” indicator. This process will be iterative, as
section of the “Basin Setting” chapter of the minimum thresholds and undesirable results
GSP. This section will provide the justification are linked together under SGMA. As with the
for each management area selected and definition of the undesirable results, Dudek will
explain how the management of separate areas conduct the technical analysis to support
within the Basin will not cause undesirable setting the minimum thresholds. This is
results in other areas of the Basin. anticipated to be an iterative process, with the
results of the predictive simulations informing
Develop Groundwater Sustainability Plan for the Yucaipa Basin Area Page 5
Yucaipa Sustainable Groundwater Management Agency - August 9, 2018 - Page 83 of 208
