• Red Rocks with water in front of them in the desert.
  • Clouds behind Joshua Tree and bushes.
  • Desert flowers blooming in bushes in front of mountains in the desert.
  • Setting sun reflecting of clouds of orange and blue behind a joshua tree.
  • Hoover Dam intake towers with water behind the dam showing that it is not full.

2012 SCIENCE PROJECTS

Assessing evapotranspiration rate changes for proposed restoration of the forested uplands of the Desert LCC

Science Need(s)

Improved monitoring and inventory of watersheds and their associated infrastructure and ecosystems;
Improved hydrologic forecasting and modeling methodologies, including better understanding and communication of uncertainty

Grantee: Northern Arizona University
Principle Investigator: Dr. Abe Springer
Cooperative Agreement: $136,734 in non-Federal funds and $135,332 in Federal funds provided by BOR
Project Duration: 2012-2014

Project Goal(s)

The goal of this work is to improve the understanding of the hydrological responses of forest thinning through detailed measurements and modeling of evapotranspiration.

Brief Project Description

Accurate estimation of evapotranspiration (ET) is essential for assessments of water balance and hydrologic responses to forest restoration treatments in uplands adjacent to the Desert LCC. As part of the Four Forests Restoration Initiative, a new paired watershed study is being planned to assess the hydrologic effects of mechanically thinning and restoring a more frequent fire regime to the ponderosa pine forests of Arizona. Water and energy balances will be measured and modeled in these paired watersheds to help inform and better plan for the hydrologic responses of future forest restoration actions. Researchers at Northern Arizona University have collected six years of eddy covariance measurements of ET in the ponderosa pine forest of Northern
Arizona. One site consists of a thinned pine stand and the other one is an undisturbed-control pine stand. These studies show a short-lived and transient decrease in ET at the thinned site similar to the hydrological results of separate paired watershed studies in Arizona's ponderosa pine forests from the 1950s to 1980s using only precipitation, stream discharge and basal area change data. We propose to 1) continue to directly measure ET via eddy covariance measurement at the thinned site, and 2) examine the capability of existing models and algorithms to predict ET of upland forests of the Desert LCC based on comparisons with ET measured by eddy covariance. Models evaluated will include BIOME-BGC, SoilWat, and Preistley-Taylor.
The results of this study will provide a validated technique for measuring landscape-scale ET in upland semi-arid forests that supply water to the Desert LCC. Because ET is the largest component of the hydrological cycle that returns water to the atmosphere, it has the largest influence on the hydrologic response of recharge and runoff processes which provide surface water and groundwater to rare aquatic resources in the Desert LCC. The proposed 2-year project will begin October l, 2012 and be completed by September 30, 2014.

Project Location

Ponderosa Pine forests in Arizona

Project Tasks

  • Examine the capability of existing ET models and algorithms to predict ET based on comparisons with ET measured by eddy covariance.
  • Final report and paper(s).

Project Deliverables

  • Data archived in digital format and when appropriate, will be in geospatial format compatible with ArcGIS with attached metadata.
  • Journal article for publication in a relevant peer-reviewed journal
  • Model simulations that will provide quantification of anticipated water resources’ effects of forest restoration, which can inform adaptive management to benefit the resource.

Documents Available for Download