Technical Report

Evapotranspiration in the Middle Rio Grande Bosque

URL: https://webapps.usgs.gov/mrgescp/documents/Cleverly%20et%20al_2007_Evapotranspiration%20in%20the%20MRG%20Bosque.pdf

Date: 2007/09/30

Author(s): Cleverly J.R., Pockman W.T., Dahm C.N.

Publication: Report prepared for U.S. Bureau of Reclamation, 21 p.

Abstract:

With the assistance of the endangered species workgroup, the Rio-ET project at UNM was enabled to uninterruptedly collect evapotranspiration (ET) measurements from a variety of sites along the Middle Rio Grande (MRG) in New Mexico. Data on ET and related hydrologic and atmospheric conditions were collected from towers and shallow groundwater wells throughout the MRG. These vital measurements were made in saltcedar, cottonwood, and Russian olive ecosystems, beginning in 1999 and continuing through 2007.

Climatic conditions in the MRG basin and its headwaters in New Mexico and Colorado ranged from moderately wet to extreme drought. ET, or depletions from the water budget from evaporation and transpiration, was undiminished at the cottonwood sites during the drought period due to maintenance of groundwater levels at both sites–one in the outflow of the City of Albuquerque’s wastewater recovery plant and the other surrounded by irrigation structures and drain channels. In the saltcedar thickets, ET was inconsistently depressed during the drought: lower ET was not observed in both locations and both years of extreme drought. Altogether, ET rates remained very high through the drought years, and plant water use returned to predrought levels within one year of release from drought.