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January 10, 2012

Severe Drought, Wildfires Threaten Water Resources

by Zulima Palacio

Scientists say severe, prolonged drought and soaring temperatures were major factors in the wildfires that destroyed thousands of hectares of forest and woodlands in the western United States last year.  They predict those conditions might continue to threaten both the region's forests and its scarce water resources.

Now a team of scientists in New Mexico's Valles Caldera National Preserve is trying to restore the damaged forest land. They're also trying to find ways to conserve water in a region that climate change is making increasingly dry.

This is Valles Caldera. Actually, it's the giant mouth of a dormant super volcano that last erupted 40,000 years ago.  In the millennia since then, the terrain developed high-elevation forests, of  abundant water sources and a rich ecosystem.  Today it's a national preserve.

But last year, over 32,000 hectares of forest in Valles Caldera, as well as in several other states of the American southwest, were consumed by the worst wild fires in a century.   

"This burned 43,000 acres [17,000 hectares] in 14 hours. To give you a kind of visual on that, a football field with both end zones and bench areas, burns in 2 seconds," noted Bob Parmenter, chief scientist at Valles Caldera National Preserve.

Parmenter says there are several reasons for that kind of fire: shorter winters with less snow pack along the Rocky Mountains, where many rivers in the American west originate, as well as longer and warmer summers with less rain.  

David Brown, a regional climate director for the National Oceanic and Atmospheric Administration (NOAA), says drought is putting heavy stress on water resources.

"One of the most severe droughts in the last 100 years is playing out right now in the southwest," said Brown.

As a result, more than a hundred scientists are working in Valles Caldera in a bid to restore ecological balance to the region, through reforestation and water conservation.

The challenges are huge.  A study by the U.S. Geological Survey revealed a 30 to 60 percent decline in the Rocky Mountain snow pack. Gregory Pederson, a climate scientist for USGS, participated in the study.

"All the water resources we need to support the societies and ecosystems comes primarily from snow.  For this neck of the world, most of the water comes from snow pack, 60 to 80 percent," said Pederson.

Data from the last several decades indicate that rivers like the Jemez River have lost 40 percent of their waters.

Trees play an important role in water preservation, says Bob Parmenter of the Valles Caldera National Preserve:

"The conservative estimate here is that the shading alone increases snow water storage up to 22 percent.  As we manage this forest, we can hopefully keep water in the streams as the climate continues to change," added Parmenter.

Parmenter and his team say restoring the forest and the ecosystem in these mountains will help ensure that the region's water resources will survive future droughts and climate change.

The team has begun thinning this forest so wildfires become less likely.