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AVGWLF Goes International
Since 2000, Barry Evans and his group at PSIEE have been improving upon a watershed modeling tool that they initially developed with funding from the Pennsylvania Department of Environmental Protection (PaDEP). This software called AVGWLF (ArcView Generalized Watershed Loading Function) provides a link between commercial GIS mapping software (ArcView) and the GWLF watershed model originally developed at Cornell University for use in simulating nutrient and sediment transport.
This modeling tool has since been recommended by the U.S. Environmental Protection Agency (EPA)
for use in federally-mandated “total maximum daily load” (TMDL) studies as well as general watershed assessments.
Since its initial development, AVGWLF has undergone numerous upgrades completed by Evans and his colleagues Dave Lehning, Ken Corradini
and Scott Sheeder (all research assistants at PSIEE), including the addition of a streambank erosion routine
and a best management practice (BMP) assessment module. The most recent version released in early 2008 now also
includes specialized routines for handling farm animal loads, a pathogen load routine, and a specialized model for use in urbanized settings.
As a TMDL and watershed restoration support tool, AVGWLF has been used by PaDEP since 1999.
It is also being used to support lake studies in New York, a “regionalized” version of it has been developed for use in
New England through a funded project with the New England Interstate Water Pollution Control Commission, and the U.S.
Environmental Protection Agency has recently asked Evans to adapt the software tool for use in the five western
states that comprise EPA Region 6. AVGWLF is now available for download at www.avgwlf.psu.edu, and since this site
was set up, it has been accessed regularly at a rate of several hundred hits per month.
In addition to being used within the U.S., AVGWLF has also been gaining an international reputation. During the last few years, Evans has spoken at a number of international conferences about the modeling tool, and he has been asked to provide in-depth training on its use to interested groups around the globe. For example, he has been advising the Mexican Institute of Water Technology on use of a Spanish-language version of AVGWLF since 1999.
He has also assisted the National Water Commission of Israel on using the model as part of a watershed management plan for the Sea of Galilee. Other countries have also found AVGWLF to be useful in supporting their water quality assessment efforts, and as a result, Evans has provided additional advice and training to groups such as the Argentine Institute of Oceanography; the Environment Agency of England and Wales; the Autonomous University of La Molina in Lima, Peru; the Province of Ontario, Canada; the Institute of Water Problems in Sofia, Bulgaria; and the Swedish Meteorological and Hydrological Institute. Most recently, he has helped researchers at the European Union’s Joint Research Centre located in Ispra, Italy use AVGWLF to quantify nutrient and sediment loads delivered to the Mediterranean Sea by surrounding countries.
In the latest wrinkle to the AVGWLF story, Evans and his group are in the process of converting AVGWLF to a completely non-commercial software environment called MapWindow. One of the primary benefits to moving AVGWLF to a “freeware” environment is that it will provide users with the ability to duplicate the functionality of AVGWLF without the need to have commercial GIS software (i.e., ArcView 3.x) installed on their computer. Additionally, MapWindow can directly use ESRI-formatted GIS data, which is the most widely-used data format in the world. A “free” version of this GIS-based modeling tool would also allow a much wider audience (e.g., local watershed groups) to conduct the kind of analyses required to support future watershed restoration efforts.
Submitted by Dr. Barry Evans (e-mail: bme1@psu.edu), director of the GIS Support Center.