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Developing a Watershed Inventory for Vulnerability Assessment Using ArcGIS

A number of data sources were combined to produce a detailed picture of the land uses and landscapes within the watershed. The 2001 National Land Cover Database, a consistent land-cover database for the entire continental United States at a 30-meter resolution, was downloaded from the Seamless Data Distribution System, National Center for Earth Resources Observation and Science (EROS) Web site ( In addition, the National Land Cover Database provides tree canopy and impervious surface data at the same resolution. For Pennsylvania, higher resolution impervious surface data was estimated by Dr. Toby Carlson of Penn State University. Available for 1985 and 2000, it shows changes in impervious surfaces within a watershed.

DVRPC made available digital land-use data interpreted from high-resolution digital orthophotography. Data from 1990, 1995, and 2000 allows an assessment of land-use patterns and land-use change. Although few areas of the country currently have available consistently interpreted, high-resolution land-use data from more than a single time period, more of this data is becoming available.

ArcGIS tools, combined with high-quality land-use and land-cover data from multiple sources allow for a detailed assessment of landscape patterns. For example, forests play an important role in both species habitat and water quality. Detailed measures of forest fragmentation can be used to assess ecosystem threats and prioritize land conservation strategies. Using an ArcGIS extension written by Kurt Paulsen of Temple University and Jianye Chen of Rutgers University, a number of measures of forest fragmentation were calculated for each subbasin. Hawth's Analysis Tools for ArcGIS were used to calculate distances between forest patches and the proximity of forested patches to streams.

BiologicalFishPhiladelphia Water Department2002
HabitatPhiladelphia Water Department2002
MicroinvertebratePhiladelphia Water Department2002
Water RelatedWetlandDelaware Valley Regional Planning Commission1981
Bridge & CulvertCenter for Sustainable Communities, Temple University 2005
DamPhiladelphia Water Department1999
Riparian BufferHeritage Conservancy2002
Effluent ConcentrationPhiladelphia Water Department2003
Discharges & WithdrawalsDelaware River Basin Commission 1996
StreamCenter for Sustainable Communities, Temple University2004
FloodplainFederal Emergency Management Agency1996
GeologicalBed Rock GeologyDelaware River Basin Commission1998
SoilDelaware River Basin CommissionUnknown
Base FlowPhiladelphia Water Department1998
DemographicHousehold DensityU.S. Census Bureau1990/2000
Median Household IncomeU.S. Census Bureau1990/2000
Population DensityU.S. Census Bureau1990/2000
Land FeaturesLand useDelaware Valley Regional Planning Commission1990/1995/2000
Land CoverUnited States Geological Survey2001
Tree Canopy DensityUnited States Geological Survey2001
Impervious SurfacePennsylvania State University, Dr. Toby Carlson1985/2000
SlopeCenter for Sustainable Communities, Temple University2004
Road DensityCenter for Sustainable Communities, Temple University2005
Forest FragmentationCenter for Sustainable Communities, Temple University2005


Watersheds are complex ecosystems with multiple hydrological, biological, political, and economic influences. ArcGIS, combined with a number of widely available extensions, serves as a powerful platform for the integration and analysis of a wide range of data sources. The tools and methods of EPA's ReVA program and the GIS strategies demonstrated in the Pennypack Creek inventory should provide environmental planners, decision makers, and citizens with a tremendous range of tools and techniques for improved watershed understanding and management.

For more information, contact

Center for Sustainable Communities
Temple University
580 Meetinghouse Road
Ambler, Pennsylvania, 19002

About the Authors

Md Mahbubur R. Meenar is a GIS coordinator for the Center for Sustainable Communities at Temple University. He received a master's degree in urban and regional planning from State University of New York, Buffalo, and earned a bachelor's degree in architecture from Bangladesh University of Engineering and Technology (BUET). His interests include environmental modeling, neighborhood revitalization, recreational planning, and three-dimensional GIS simulations. He can be reached at

A.S.M. Abdul Bari is a GIS coordinator for the Center for Sustainable Communities at Temple University. He received a master's degree in urban and regional planning from State University of New York, Buffalo, and earned a bachelor's degree in architecture from BUET. His interests include urban design, environmental planning, and alternative methods of transportation. He can be reached at

Kurt Paulsen is an assistant professor in the Department of Community and Regional Planning at Temple University. His research focuses on utilizing GIS and quantitative methods in models of land-use change and in the relationship between land development and local public finance. He earned master's degrees in agricultural and applied economics and in policy and public administration, both from the University of Wisconsin. He received a doctorate in urban planning and policy development from Rutgers University. He can be reached at

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