The Sustainable Groundwater Management Act, which takes effect Jan. 1, requires that the Department of Water Resources categorize each of California’s 515 alluvial groundwater basins and subbasins as high, medium, low, or very low priority by Jan. 31. DWR published basin prioritization results in June that provides a likely “preview” of its impending Jan. 31 priorities. DWR has provided a map of these results on its CASGEM website.

The Act will impose new requirements on high and medium priority basins, specifically that each basin be sustainably and cooperatively managed, on a basin-wide scale. Any local agency, which is defined under the Act as a local public agency having water supply, water management, or land use responsibilities within a basin, may elect to be, or join other agencies in forming, a Groundwater Sustainability Agency to implement sustainable groundwater management.

Many of these basins and subbasins, as defined by DWR’s Bulletin 118, involve complex issues, spanning hundreds of thousands of acres, crossing multiple counties and implicating dozens of local agencies such as counties, cities and water districts that utilize groundwater resources and carry out land use planning. The Act also requires groundwater sustainability plans to consider the interests of all beneficial uses and users of groundwater, including:

• domestic and agricultural overlying rights,
• environmental uses of groundwater,
• surface water users if there is a hydrologic connection to groundwater,
• the federal government,
• California Native American tribes, and
• disadvantaged communities.

To say the least, sustainable groundwater management plans will require entirely new levels of technical, legal and political coordination.

Furthermore, many groundwater basins throughout the state are currently managed according to boundaries that are hydrologically justified, yet which differ from the boundaries designated by Bulletin 118. The Act provides a means to petition DWR to change basin boundaries, or to form new subbasins, if there is justification for so doing and if it will assist with sustainable groundwater management. By Jan. 1, 2016, DWR must adopt emergency regulations, including methodology and criteria, to evaluate proposed basin boundary changes.