NASA to Help Manage California’s Water Resources

Water is fundamental to life on Earth. Knowing where and how much rain and snow falls is vital to understanding how weather and climate impact our environment, including the effects on agriculture, fresh water availability and natural disasters. Nowhere is this better seen than in California. The California Water Plan, a regular analysis published by the California Department of Water Resources (DWR) is the major guide book for water planning within the state. The latest version of the Plan was released for public review in January 2009 and updated in 2013. It stated: “We must adapt and evolve California’s water systems more quickly and effectively to keep pace with ever changing conditions now and in the future. Population is growing while available water supplies are static and even decreasing.”

The powerful Pacific storm that brought rain and snow late last week through much of California. Communities endangered by wildfire just weeks ago, faced mud and debris landslides and flash floods. The much prayed for rain came in a massive deluge as it often does. On Friday 4.3 inches of rain fell on Los Angeles almost three times as much rain as had fallen in the region since July. The parched ground and hillsides stripped bare by wildfires were less able to absorb water and several communities experienced mudslides and flash floods. The storm front moved on to the east bringing more snow to the east coast.

Despite the enormity of the deluge, these storms will not rescue the region from the three years of below-normal rainfall, California still looks to be facing its most severe drought in decades. It would take rainfall of almost biblical proportions to make up the water shortfall that California faces. If you recall Governor Jerry Brown has declared a drought emergency and water allocations had been cut to zero by state and federal water manages. Though, this storm did bring some relief to rural and smaller communities especially in Northern California whose water supply was forecast to run dry in the next two months.

In the past California’s state water agencies could not even track how much water is actually being used, where it is being used, where it is being diverted to, how much is being diverted, or how many diversions are illegal. The ability to track water usage and accurate long range forecasts of precipitation would allow California water manages to better capture and store the precious water. The California DWR announced last week that they will be working with NASA to apply new technology to better understand, monitor and manage the state's water resources and respond to its droughts and changing water needs. NASA scientists, university researchers and DWR water managers will work together to apply advanced remote sensing and improved forecast modeling to better assess water resources, monitor drought conditions and water supplies, plan for drought response and mitigation, and measure drought impacts.

DWR first began working with NASA on the Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to quantify groundwater depletion. A group of researchers at the University of California, Irvine, the University of Texas, and the Hydrological Sciences Branch at NASA GSFC have worked in partnership to apply GRACE and GLDAS to various real world groundwater monitoring with funding from the 2009 American Recovery and Reinvestment Act. The GRACE scientific team will launch the next generation of GRACE satellites able to monitor groundwater changes on a weekly basis and to be able to monitor groundwater and river basins that are 1,000 square miles in area. In addition, this partnership will provide the resources to interpret the date in a more timely fashion so that communities can use it to manage water resources in real time.

In California's Central Valley groundwater was pumped to such an extent that the ground subsided more than 75 feet in some places. The area was identified by the research efforts of Joseph Poland in the 1970’s as the location of maximum subsidence in the United States due to groundwater mining. Once the land subsides, it loses its water holding capacity and will never recover as an aquifer. Recent GRACE data has indicated that the groundwater level is once more falling due to over pumping. The groundwater resources of the state need to be managed with the surface water resources and the partnership with NASA holds promise of providing tools to do just that.

In addition, NASA is now planning on using their remote sensing data and research to monitor the California delta levees; map fallowed agricultural lands; and improve estimates of precipitation, water stored in the winter snowpack, and changes in groundwater resources. The agencies also are working to combine data from NASA satellites and DWR's network of agricultural weather stations to improve estimates of crop water requirements for California farmers seeking to better manage irrigation.

Next month, NASA and DWR will resume flights of NASA's Airborne Snow Observatory to map the snowpack of the Tuolumne River Basin in the Sierra Nevada and the Uncompahgre watershed in the Upper Colorado River Basin. The Tuolumne watershed is the source of the water supply for 2.6 million San Francisco Bay Area residents. The airborne observatory measures how much water is in the snowpack and how much sunlight the snow absorbs, which in turn affects how fast the snow melts. This information would allow NASA and DWR to make accurate estimates of how much water will flow out of a basin when the snow melts. Last year, observatory data helped water managers optimize reservoir filling and more efficiently allocate water between power generation, water supplies and ecological uses.

Another pilot project is demonstrating the feasibility of using satellite imagery to track the extent of fallowed land -- cultivated land intentionally allowed to lie idle during growing season. NASA is working with DWR, the U.S. Department of Agriculture, the U.S. Geological Survey (USGS) and California State University at Monetary Bay to establish a fallowed land monitoring service as part of a California drought early warning information system. New methods using time-series of crop data from NASA and USGS satellites can provide information on land fallowing and reductions in planted acreage early in the year. The team is preparing to produce data and maps of fallowed acreage in the Central Valley beginning this April to help monitor the impacts of the ongoing drought.

Over the next seven years NASA plans to launch four additional water-related satellites to add to the more than a dozen NASA satellites focused on understanding detailed Earth science processes. NASA also monitors Earth from ground-based observation posts. NASA is working to develop new ways to observe and study Earth's interconnected natural systems using the long-term data records and computer analysis tools to better see how our planet is changing and contribute to understanding and protecting our home planet.

These programs are not going to increase the water available to California, and they will likely reduce individual choice, but they may allow the state to rationally manage the resources available to it. I say maybe because California and its population has demonstrated an inability to face and accept harsh truths and plan rationally for the future. There seems to be a tendency to engage in magical thinking. Hope for the best, plan for the worst and carefully monitor the facts of the situation.