Sierra is white with snow, but more drought solutions needed

Roger Bales
January 21, 2016


Yes, it's raining and snowing, but drought damages must be addressed.
Subsidence is a serious issue in much of the Central Valley.
Federal, state and local agencies need much greater cooperation. 

USGS Subsidence in CA Central Valley
Land subsidence in the San Joaquin Valley, California, 1926-70. 


Prof. Roger Bales, UC Water DirectorYes, it’s nice to see snow, and those Californians dreaming of a white Christmas saw that dream come true in the Sierra. But dreaming isn’t going to solve the state’s long-term water problems.

For that, we need shared strategy and cooperation.

The drought brought unprecedented change to the Sierra Nevada headwaters. Tree mortality rates are up to 50 percent in some mixed-conifer forest areas. A record number of acres have experienced high-intensity wildfires.

We must use systemic thinking to integrate management of our source-water areas such as the Sierra Nevada – much of which is federal land – with our largely state-controlled groundwater aquifers.

Even if El Niño brings more rain and snow this year, the state will still have a large imbalance between supply and demand; and the greater uncertainty added by climate warming makes managing those imbalances even more challenging.

In addition to congressional action on a water bill, federal agencies can do more within existing programs to provide both immediate drought relief and lasting solutions.

There are some key individual programs – or components of integrated regional solutions – that federal-state partnerships can implement now, including:

  • Groundwater recharge on farmland and in expanded floodplains;
  • Agricultural incentives for groundwater recharge and traditional conservation measures;
  • Forest management.

Drought-response and grant programs within the Bureau of Reclamation, the Natural Resources Conservation Service and other agencies can enable these solutions. The U.S. Geological Survey can support decision making at local agencies through additional sharing of data and expertise.

Long-term over-pumping of groundwater, accelerated during the drought to make up for decreases in irrigation flows from California’s reservoirs and rivers, has depleted underground water levels and increased land subsidence.

A recent assessment released by the California Department of Water Resources reported a shocking drop in land surface during 2014 of up to 12 inches in two San Joaquin Valley areas. The USGS reported even greater land subsidence over the previous decade.

Already, bridges and roads are cracking and buckling. In an ironic twist, the capacity of the state’s network of canals that send water throughout California is at risk of being reduced.

Approximately 75 percent – or 30 million – Californians, including virtually everyone in the Central Valley, depend on groundwater for a portion of their supply. For many, it is their only supply.

On average, groundwater provides about 40 percent of our agricultural and urban water uses.

Groundwater is used alongside surface water to meet the state’s needs, which range from urban and industrial uses to irrigating roughly half the fruits and vegetables grown in the U.S.

The recent mining of groundwater has taken well levels to record low depths – in some places more than 100 feet lower than previous dry periods. Those declining levels have contributed to more than 2,500 domestic wells throughout the state going dry and thousands more paying higher energy bills to pump water from greater depths or having to drill new wells.

Sustainable groundwater management is an essential pillar of Gov. Jerry Brown’s five-year California Water Action Plan, which was updated just last month. It formulates broad actions to achieve sustainable water-resource management, including the overarching goals to establish resilient resources that can be relied upon for future generations.

In 2014, California passed the historic Sustainable Groundwater Management Act, which provides the rules and framework for sustainably managing California’s groundwater basins by 2040.

That’s commendable, but we need to do more between now and then.

We need regional cooperation to invest in infrastructure improvements to maximize water capture for storage above and below ground; and we need timely, transparent, accurate water-resources information. Together, these are foundations of water security.

There is no single path to sustainability.

Strategic, collaborative action between local, regional, state and federal agencies – plus the private sector – to plan, invest and operate our water systems efficiently can lead to effective solutions.


Roger Bales, a founding faculty member and distinguished professor of engineering at UC Merced, has worked on California water and climate issues for nearly 40 years. He is director of UC Water and the Southern Sierra Critical Zone Observatory.

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