

Water at the surface is connected to the water hidden below.

The water from California’s rivers and streams, along with rainwater, seeps into the ground, where it remains among the rocks, gravel and sand. Between these surface and sub-surface supplies lies the water table, which is what hydrologists call the top of the area that has been saturated underground.

Using too much groundwater affects not only surface water supplies but also entire ecosystems. Pumping from the earth deep enough to suck water out can lower the groundwater table and dry out surface soils.

Rivers and streams feed more than 500 aquifers around California. Less than a quarter of these account for the overwhelming majority of groundwater pumping.

In these basins, this landmark law already has begun to transform the Central Valley.

For decades, farmers fought the regulation and monitoring of groundwater tooth and nail. Now that it’s here, SGMA has already begun to change the region’s economy and landscape, as some farmers have sold or fallowed land in antipation of the coming changes.

The Public Policy Institute of California predicts that agricultural interests may have to let 750,000 acres of land go fallow, mostly in parts of the San Joaquin Valley where the most severe overpumping has occurred.

Farmers may also have to cycle current crops out for those requiring less water. For example, almonds are water-intensive but have been profitable in recent years; those margins would change if water becomes much more expensive than it is now.

Some local water managers have a lot of work to show by the end of the month.

There are 21 “critically overdrafted” basins for which officials must submit groundwater management plans by Jan. 31.

In each area where people have habitually pumped more than has come back in, local water managers have to figure out how much they’ve taken from underground, and how water at the surface replenishes those stores. Each region has to propose ways to monitor groundwater over multiple intervals: day-to-day, short-term, seasonal, and yearslong. Basically, they’re creating monitoring systems, in some cases from scratch, to help determine whether conditions are changing.

The groundwater plans are built around models for how to share water in a way that’s sustainable by 2040. Each one can be a little different, but local managers and the state have to check up on every single one and meet interim deadlines every five years.

The Department of Water Resources can accept the plans as is or ask for tweaks. DWR can also refer the plans to the state water board for intervention, meaning that local officials may have to try again if the state judges a plan unlikely to succeed. In extreme cases, the state may have to step in to settle disputes over local rights.



This isn’t just a Valley problem.

Balancing aquifers like bank accounts will cost money and effort in the Bay Area and other parts of the state. Two years from now, managers for dozens more groundwater basins with state-designated risk ratings of high or medium must submit their own plans to the State Water Resources Control Board. They include water managers in Sonoma, Napa, San Mateo and Santa Clara counties.

Even though these plans will take years to come into focus, plenty of political decisions remain.

State requirements for sustainable regional groundwater management haven’t taken away anyone’s rights; the rules have changed how localities must meet their water needs from now on. Even the plans submitted by the locally formed groundwater agencies that will meet this year’s deadline haven’t absolutely nailed down who gets to use what in the future. The coming decisions and politics about water may be tense, but the alternative is that one day, wells could run dry.