Water Resource Management and Planning for SCV Water

Since 2000, GSI has conducted numerous water resource management and planning studies for SCV Water and its predecessor wholesale and retail water agencies that have focused on sustainable management and use of local groundwater supplies. These studies have also evaluated future conjunctive use opportunities involving recharge of the valley’s surficial and deeper aquifer systems using imported water supplies, treated water, and/or stormwater.

Much of this work has included the use of a basin-wide, multi-layer, regional-scale groundwater flow model of the Santa Clarita Valley. GSI personnel built the model and have applied it for several different groundwater management purposes on behalf of SCV Water. GSI continues to update the model as basin monitoring continues over time and data gaps are filled.

GSI’s work has also supported several state-required water plans, including the past three Urban Water Management Plans, the Salt and Nutrient Management Plan, and the Groundwater Sustainability Plan for the basin. Other related planning studies have included a water supply reliability plan and plans/programs for containing a contaminant plume emanating from a large contaminated site that has impacted certain municipal supply wells owned and operated by SCV Water.

GSI's work involved:

• Evaluating the long-term sustainability of the basin’s aquifers.
• Assessing offsite pumping strategies to capture, contain, and prevent further spreading of a perchlorate plume.
• Developing time-varying groundwater budgets for the basin’s Salt and Nutrient Management Plan.
• Evaluating options for infiltrating treated water and/or imported water supplies into the alluvial aquifer via spreading basins.
• Assessing aquifer storage and recovery (ASR) of imported water supplies as a method for augmenting groundwater pumping capacities during curtailment years.
• Evaluating temporary groundwater pumping redistribution to respond to short-term water level declines in certain alluvial production wells during drought conditions.
• Analyzing the potential range of effects of climate change on groundwater recharge rates and timing (from precipitation and streamflows).
• Leading the development of a groundwater sustainability plan for the basin (approved by the Department of Water Resources in January 2024).