Soapbox

Groundwater recharge could help replace storage function of Hetch Hetchy

Improved groundwater recharge, managed conjunctively with other surface storage on the Tuolumne River, could replace the storage function provided by Hetch Hetchy Reservoir.
Improved groundwater recharge, managed conjunctively with other surface storage on the Tuolumne River, could replace the storage function provided by Hetch Hetchy Reservoir. New York Times file

The forecast of a “Godzilla El Niño” in 2016 sounds pretty good in drought parched California. Many of us are willing to risk a few floods and mudslides if the abnormally warm waters of the eastern Pacific can produce winter storms that will engulf our streams and fill our reservoirs.

Filling our surface reservoirs would certainly put us at ease. That relief, however, would only last a year or two if succeeding years are dry. California needs a long-term plan, using a wide variety of water management tools, to better and sustainably supply water for our cities, our world-class farms and our precious environment.

Perhaps no single tool is as important as increasing groundwater recharge in wet years. Gov. Jerry Brown has rightly touted the importance of the landmark Sustainable Groundwater Management Act, passed by the Legislature a year ago. The act, however, will be implemented over time – and not fully so until 2040. That is much too slow.

We all know that California has a huge problem with groundwater depletion. The U.S. Geological Survey reports we have overdrawn groundwater by 125 million acre-feet over the last century – more than three times the total capacity of our surface reservoirs.

The lesser-known story is that we have opportunities to recharge many depleted basins in wet years. The most critical element for making a successful recharge program possible – one that is too often missing – is a clear agreement between landowners and water users for controlling the subsequent extraction of stored water.

The Kern Water Bank was developed for a small fraction of the cost of a new dam. Wet year supplies are diverted from the California Aqueduct to recharge groundwater beneath the former Tulare Lake Bed. The investment has allowed Paramount Farms, the bank’s leading investor and California’s largest agricultural enterprise, to safely invest in orchards throughout the San Joaquin Valley. While there is controversy – and litigation – over whether a handful of private entities should control so much of California’s water, no one disputes it was a cost-effective project.

Groundwater recharge has been successful in other parts of the state as well, especially when operated “conjunctively” with surface reservoirs. The upper San Joaquin River flows into Millerton Reservoir, where water is then diverted to farms along the Friant-Kern Canal. In wet years, runoff into Millerton is funneled to “spreading basins” for recharging groundwater. These stored supplies help during dry years when surface water deliveries are diminished.

In the Bay Area, San Francisco is implementing an effective program to refill the “Southwest Basin” just outside its boundaries. Neighboring cities will forgo their usual pattern of pumping free groundwater in wet years, so the basin will refill and more supply will be available in dry years. This aquifer can store about 60,000 acre-feet or about one-sixth of the volume of Hetch Hetchy Reservoir.

Unfortunately, these local success stories are the exception rather than the norm. Groundwater recharge programs need to be implemented statewide, and as soon as possible. Where there is no agreement over who owns or controls groundwater, however, there is no incentive to pursue recharge opportunities.

Fixing our groundwater problem will not only provide supply benefits, it can fix environmental problems as well. Improved groundwater recharge, managed conjunctively with other surface storage on the Tuolumne River, could easily replace the storage function provided by Hetch Hetchy Reservoir. Such an investment would allow the eponymous Hetch Hetchy Valley to be returned to Yosemite National Park and the people of California and America without losing a drop of water supply.

Spreck Rosekrans is executive director of Restore Hetch Hetchy.

  Comments