About MapShed

Objective MapShed, which evolved from the previously-developed AVGWLF software, is a customized GIS interface that is used to create input data for an enhanced version of the GWLF watershed model originally developed at Cornell University. In utilizing this interface, the user is prompted to identify required GIS files and to provide other information related to ―non-spatial‖ model parameters. This information is subsequently used to derive values for required model input parameters which are then written to the input file needed for model execution. With MapShed, a user selects areas of interest, creates model input files, runs the simulations model, and views the output in a series of seamless steps. Another tool provided with MapShed called PRedICT provides the ability to evaluate potential pollutant load reductions that might be achieved via different levels of BMP/mitigation measure implementation within a watershed.

Developer Dr. Barry M. Evans and associated staff at the Penn State Institutes of Energy and the Environment.

Contact information Dr. Barry M. Evans,, 814-865-3357, Land & Water Building, Penn State University, University Park PA 16802.

Inputs Various GIS data layers and weather data are required to use MapShed. Data sets for Pennsylvania and some other states will soon be available at Users can also create their own data using the format guide provided at the same web location.

Outputs MapShed provides daily, monthly and annual estimates of sediment, nutrient and pathogen loads at the watershed scale. This information is provided in both tabular and graphical form

User MapShed was designed for use by individuals having a mid-level understanding of water quality and watershed-scale transport processes.

Scales of Relevance MapShed is probably best used at watersheds ranging in size from about 5 to 100 square miles.

Other MapShed, and its’ pre-cursor AVGWLF, were originally designed to support TMDL analyses and similar watershed assessments. AVGWLF has been used by the Pennsylvania DEP since 1999, and various versions of AVGWLF and MapShed are being used throughout the U.S., as well as in Canada, Mexico, Israel and several other countries.

Sponsors/funders The development of both MapShed and AVGWLF has primarily been supported by funds from the Pennsylvania Department of Environmental Protection and the U.S. EPA, with additional funding from the New England Interstate Water Pollution Control Commission.