LAND USE/LAND COVER CHANGE OF SMALL (SUB)URBANIZING WATERSHEDS: REMOTE SENSING CLASSIFICATION AND GIS COMPARISON

Northampton County, Pennsylvania is one of the fastest growing regions in the state, due to its proximity to Philadelphia, and New York City. Being a bedroom community to these metropolitan areas, the rural character of the region is slowly diminishing as development pressures increase. This land use change has dramatic affects on the water quality, and erosive capability of the small streams within the watersheds.

The Martin's-Jacoby Watershed, consists of six high quality watersheds, and a number of smaller watersheds that drain directly into the Delaware River. The Martins Jacoby Watershed Association is currently completing a watershed protection plan to provide detailed mapping of the natural features within the watershed. This protection plan will be used with zoning from local municipalities to encourage growth that does not have adverse affects on the watershed, and the quality of the streams.

To provide some estimate of land use/land cover change in the watershed, Landsat images from the NALC program (1973, 1987, 1991), as well as more recent images (1999, 2002) are being used to quantify amounts of land use/land cover classes. Using unsupervised classifications, land cover changes can be quantified over the 30 year period covered by the images. Classifications show the expected increase in urban land cover, along with a decrease in agricultural and forested land, presumably as a result of the urbanization.

Using high resolution (1 m pixel) aerial photography within a Geographic Information System, the classification of the remote sensing imagery is being tested for accuracy. The identification and digitization of impervious surfaces (buildings, parking lots, roads), forests, and agricultural areas from the aerial photography , will allow for a verification of the values of the remote sensing classification, as well as a recent (2005) classification of the watershed.