Sustainable water supply is a crucial factor when seeking approval to build and operate renewable energy projects in remote California locations. With municipal water infrastructure and surface water sources typically not available, groundwater is often the most practical water supply option for construction and long-term operations.
However, groundwater is subject to increasingly complex assessment requirements as California counties update their general plans. Many of California’s 118 groundwater basins are in a state of moderate to severe overdraft (current and future water demands exceed estimates of available supply) due to agriculture, industry, and municipal draws upon the supply.
Obtaining an up-to-date understanding of the specific Groundwater Basin Management Plan (GBMP) encompassing a project is essential for renewable energy project due diligence.
The GBMP may have been prepared by one or more agencies, including the California Department of Water Resources, regional water supply districts and water companies, county planning departments, and the California Regional Water Quality Control Boards. In some instances, a specific site may be located within overlapping water basin plans, with an undetermined primary jurisdiction.
The GBMP attempts to quantify the balance of the basin’s water use versus available estimated supply and ensure the delivery of pollutant-free potable water. The typical plan summarizes water use reported in acre-feet per year, water levels monitored in wells, precipitation data analysis, estimated infiltration and recharge rates, surface water inflow and outflow, geologic studies, water quality analyses, and tracking of population and land use changes.
In some cases, the GBMP identifies corrective actions to mitigate existing basin overdraft or to avoid future overdraft. The sophistication of GBMPs is highly variable, depending on the expertise, resources, and data available used to evaluate a basin.
The following approach will help renewable project developers evaluate a GBMP to identify the groundwater supply options available:
- Quantify construction and operational water requirements for the project
- Identify any other reliable, affordable water supply for both construction and operation
- Note the designation of “off-site water sources only” or “no groundwater use” in the application
- Carefully quantify groundwater resources available from the GBMP
- Obtain a legal determination of the water rights associated with the project property
- If necessary, complete a groundwater supply assessment per local agency requirements.