Contact:	Julie Coonrod, 277-3233 Cliff Dahm, 277-2850 Michael Padilla, 277-1816
May 22, 2002 UNM RESEARCHERS ARE STUDYING THE EVAPORATION AND TRANSPIRATION OF WATER USED BY TREES IN THE MIDDLE RIO GRANDE Researchers at the University of New Mexico are investigating the rates of evaporation and transpiration of water used by trees in the Middle Rio Grande Bosque and are offering solutions to better conserve water by creating restoration projects along the river. The project, “Evapotranspiration along the Middle Rio Grande Bosque,” was conducted by Civil Engineering Assistant Professor Julie Coonrod, Biology Professor Cliff Dahm, Research Assistant Professor James Cleverly, Biology Field Research Technician Jim Thibault, and biology Ph.D. student Dianne McDonnell. Coonrod recently presented the research at the American Society of Civil Engineers annual spring meeting in Albuquerque. Evapotranspiration is the combination of water entering the atmosphere —evaporation, and water that goes through the plant into the atmosphere —transpiration. The researchers are using seasonal information generated from four towers that are placed along the Rio Grande Bosque. Two towers are placed in cottonwood sites and two in salt cedar sites. Information is entered into a Geographical Informational System (GIS). Coonrod said that Landsat imagery combined with the field measurements can be used to estimate evapotranspiration for the entire Middle Rio Grande Bosque. “With the information we are gathering we can estimate water savings by changing vegetation along the river,” Coonrod said. “The better we can quantify the water budget then the better we can offer solutions to allocate demands for water.” Part of the project is to educate individuals in water distribution. Coonrod said that they are working closely with the Interstate Stream Commission and the Bosque Improvement Group. Coonrod says that a an average household uses about 1 acre-foot of water (325,851 gallons, the amount needed to cover one acre with one foot of water) per year and approximately 1/3 acre of bosque (cottonwood + invasive species understory) uses an equivalent of 1 acre-foot per year. The project was initially funded through a NASA grant for $700,000 with Dahm serving as primary investigator. Dahm is also the lead author on one of the recent papers from the project highlighting water use by riparian vegetation on the Middle Rio Grande bosque titled, “Evapotranspiration at the Land/Water Interface in a Semi-Arid Drainage Basin.” ###

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