| Between January 2000 and
February 2005, The Idaho Department of Water
Resources and the University of Idaho's Department of
Biological and Agricultural Engineering worked on a NASA
Synergy grant to develop an efficient and accurate method of
mapping evapotranspiration.
IDWR and UI worked, first, with the Surface Energy Balance Algorithm for Land
(SEBAL). SEBAL was significantly modified into METRIC (Mapping EvapoTranspiration
with High Resolution and Internalized
Calibration). Both SEBAL and METRIC
are energy
balance models. they use satellite image-data to compute a
complete radiation and energy balance, sensible heat, and
evapotranspiration (ET) for each pixel of the
satellite image. For this application, IDWR and UI used Landsat
ETM+ data.
The goal of the project was to develop METRIC into an
operational tool for IDWR to use in administering Idaho water.
This project was one of eleven 'Infomart'
projects across the United States awarded as part of a NASA
program called the Earth
Observing System Data and Information System (EOSDIS).
The Raytheon Company administered these Infomarts as part of
their Synergy
Program. In addition to the support from Synergy, this work
was supported by funding from The
Idaho Department of Water Resources, the University of
Idaho's Departments of Biological and Agricultural
Engineering and Civil Engineering, and by the U.S. Bureau of
Reclamation.
The Idaho Synergy project was
structured in phases. Each phase was designed to stand on its
own, with self-contained goals, tasks, and products, while
building on the accomplishments of previous tasks.
Phase I (1/12000 - 12/2000)
of the project was completed at the end of 2000. Phase I was
limited in scope, designed to apply the European SEBAL to
the Bear River Basin in Idaho, to evaluate the results, and
to suggest modifications if necessary. The results of Phase
I were encouraging, and Phase II was funded.
Phase II (1/2002 - 12/2001) was a much more ambitious
project, processing multiple years of Landsat data through
SEBAL on the Eastern Snake River Plain. The work included
making modifications to the SEBAL model suggested by Phase
I, the comparison of SEBAL ET with ET measured by the
precision weighing lysimeters at the Kimberly Research
Station near Twin Falls, and the comparison of
SEBAL-computed ET with estimated ground-water pumpage for
water rights on the Eastern Snake Plain. Phase
Phase III (1/2002 - 12/2002)
was designed to further refine the SEBAL model, and to
demonstrate that it could be used operationally as a tool
for administering water-rights. It is with the Phase III
modifications that METRIC fully diverged from SEBAL
Phase IV (1/2003 - 12/2003)
was designed to begin the transition to an operational
system. Phase V (1/2004
- 2/2005) was designed to finish the transition of METRIC into an
operational system. |
