With the passage of the Sustainable Groundwater Management Act (SGMA) came the requirement for the California Department of Water Resources (DWR) to “prepare and publish a report by December 31, 2016, … that presents the department’s best estimate … of water available for replenishment of groundwater in the state.” (Wat. Code, § 10729(c).) On April 1, 2016, DWR released its “Water Available for Replenishment White Paper” (White Paper) as its initial response to the “water available for replenishment” requirements in SGMA, and to provide background information to support these requirements and identify next steps for completing the Water Available for Replenishment Report (WAFR) by December 31, 2016. Local agencies are encouraged to review the White Paper and follow development of the WAFR because SGMA requires Groundwater Sustainability Agencies (GSA) to prepare Groundwater Sustainability Plans (GSP) that include “[a] description of surface water supply used or available for use for groundwater recharge or in-lieu use.” (Wat. Code, § 10727.2(d)(5).)

For analytical purposes, DWR separates the phrase “water available for replenishment” into two parts – i.e., “water available,” and “for replenishment of groundwater.” DWR’s division assumes that there will be two distinct planning processes associated with using available water for groundwater replenishment. The first involves quantifying water available from various methods, and the second entails analyzing the replenishment potential of a groundwater basin.

According to the White Paper, DWR will develop planning level estimates of the quantity of water available from various methods, including surface water (including stormwater), conserved water, recycled water, desalination, and water transfers, among other methods. With respect to surface water, these estimates will not account for specific factors such as instream beneficial uses or other regulatory considerations typically involved in the State Water Resources Control Board’s analyses of water availability in the context of evaluating a new appropriation. The estimate for surface water will quantify the water that could be made available in excess of total water use by hydrologic region, using current operations, and regulatory requirements. For conservation, recycled water, desalinated water, and water transfers, DWR will use planning level estimates that reflect amounts local agencies estimate will be available in their service areas.

The WAFR will also evaluate replenishment opportunities. DWR interprets the term “for replenishment of groundwater” to have a meaning similar to SGMA’s definition of “groundwater recharge.” SGMA defines “groundwater recharge” as [t]he augmentation of groundwater, by natural or artificial means.” (Wat. Code, § 10721(i).) DWR will analyze both “active recharge” and “in-lieu recharge” in the WAFR. Active recharge includes “direct spreading” – i.e., ponding water in percolation basins where it infiltrates downward into unconfined aquifers – and “aquifer injection” – i.e., injection of water into confined aquifers using aquifer storage and recovery wells. DWR will also analyze opportunities for “in-lieu recharge” – providing an alternative source to those that would normally use groundwater, thereby reducing groundwater use.

The White Paper clearly recognizes the challenges and uncertainties associated with estimating the water available for replenishment of groundwater. DWR acknowledges that estimates need to consider the spatial, temporal, and physical mechanisms involved in making water available for replenishment of groundwater basins. The White Paper indicates that DWR’s estimates will be influenced by data availability, water quality requirements, operations and infrastructure capacity, regulatory issues, and financial considerations.

DWR envisions that the WAFR will assist GSAs in planning for and achieving sustainable groundwater management. To this end, the WAFR will include roadmaps to guide GSAs in determining water available for replenishment planning, and assist in review and selection of replenishment projects. DWR will develop estimates of water availability at the hydrologic region and planning area level, which means that GSAs will need to calculate their own water availability at a local level for inclusion in GSPs. The roadmaps will assist these local efforts by describing how to quantify water available and the effectiveness of replenishment.

DWR will continue to engage stakeholders and GSA representatives as it develops the WAFR, and welcomes comments on the White Paper to help inform this process. Comments can be directed to sgmps@water.ca.gov. To view a copy of the White Paper and related materials, please visit: http://www.water.ca.gov/groundwater/sgm/wafr.cfm. For more information on this topic, please contact Aaron Ferguson at (916) 446-7979 or aferguson@somachlaw.com.

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