Sandia LabNews

Labs water resource simulator rapidly calculates tomorrow's supply given today's choices

By 2015, according to experts, half the world’s population — 3 billion people — will lack access to fresh water. (See "Why water is a national security issue," on page 4. )

A team of Sandians is developing software models they think might help not only regions and nations with seemingly hopeless water shortages, but also water-wary areas such as the Southwestern US where sound resource management might still avert a crisis.

The simulations, called Dynamic Water Budget Models, allow decision makers to see how water policy options selected today will affect a society’s water resources decades into the future.

The developers include Dick Thomas (6115), Steve Conrad (6515), Vince Tidwell (6115), Erik Webb (6115), and Cara McCarthy (University of Arizona).

Exploring policy options

The models are built on the commercial Powersim software tool, which Sandia has used to study everything from summer blackouts in California to global nuclear material inventories. The intuitive user interface allows easy changes to inputs and immediate extrapolation and visualization of results. Making policy changes is as simple as fiddling with a few knobs, says Dick.

But underneath it all is a complex model not only of water uses but of the subtle interrelationships among ground and surface water sources, recharge rates, groundwater pumping, irrigation, climate, evapotranspiration, and demographics. Future models will include other factors, such as environmental impacts, water quality, economic productivity, and an area’s social and cultural foundations.

"There are modeling tools that provide greater fidelity in modeling individual components of the water system," says Erik. "We’ve abstracted and combined those kinds of models to ask what the water resource picture might be 20 years down the road. This is the only model we’ve found that allows for big-picture, long-term planning."

Thinking globally, acting locally

Development of the tool, first envisioned by Dennis Engi (16000) in 1986, has been funded primarily through the Laboratory Directed Research and Development (LDRD) program.

Dick and Steve built the first model in the mid 1990s to examine water supply and demand trends for China’s 10 major water basins, concluding that water will become a limiting factor in the country’s ability to feed itself during the next two decades as China’s major agricultural areas run increasingly large water deficits.

The simulations were part of a Harvard University study that helped alter the way some experts now think about China’s future.

"China’s goal is to be a self-sufficient nation with regard to grain production," says Steve. "Our conclusion was that China is not going to be self- sufficient unless something changes drastically."

The team then used the Middle Rio Grande Basin, the basin that supplies water to the Albuquerque area, as a testbed for developing the tool further.

"It’s a way of helping our community with sustainability issues while also creating a tool that could help the nation and the world," says Dick.

Working with the US Geological Survey and the state engineer’s office they built a model that shows, not surprisingly, that current water use practices in New Mexico are not sustainable.

The team continues to work with city planners in Albuquerque and Rio Rancho to apply the tool to Albuquerque-area policy-making efforts, in cooperation with the UNM Law School’s Utton International Transboundary Resource Center.

Workable vs. unworkable options

A similar model of New Mexico’s Estancia Basin, in cooperation with the Estancia Basin Water Planning Committee, is helping show farmers and developers the possible results of various development schemes and agricultural practices for the area.

"Different users have different ideas about what optimal use of the water resource is," says Dick. "We helped get them talking sooner about realistic approaches rather than dwelling on unworkable, unsustainable options."

The team expects to deliver to officials a web-based version of the Estancia Basin model in four to six months as part of a project sponsored internally by Corporate Outreach Dept. 12650.

They also are exploring, in cooperation with Sandia’s Cooperative Monitoring Center, the possibility of modeling water issues for basins shared by countries of the Former Soviet Union, for nine countries that border the Nile River, and for the US and Mexico in the El Paso/Cuidad Juarez area. The team has demonstrated the model to local school children as well.

"It’s a great educational tool," says Steve. "Anybody can play their own ‘what if’ game. It allows different people with different stakes in the outcome to rapidly test the long-term effects of many policy options. It’s very democratizing."