Study shows trees regulate water usage

NORTH PLATTE -- Preliminary results from an evapotranspiration study along the Platte River indicate that trees in riparian systems regulate water intake according to atmospheric conditions, said David Rus, U.S. Geological Survey hydrologist.

Some water use estimates for cottonwoods and other trees that have their roots in shallow groundwater 60 to 70 inches of water per year, but preliminary estimates from monitoring along the Platte System between 2002 and 2004 showed that the average was closer to 21-23 inches annually, Rus said.

"What we've found is that the plants regulate themselves down so that their water usage reflects atmospheric conditions," Rus said.

He said that the Cooperative Hydrology Study Group is using evapotranspiration studies in its ground water/surface water model to study stream depletion. Amid discussion of multiple management scenarios for riparian woody plants, the studies can provide decision-makers with more information.

Rus said that the CHSG studies are continuing and that another, funded by the Central Platte Natural Resources District and the Environmental Trust will start soon. These studies will provide the scientific basis for management decisions along Nebraska's rivers, he said.