GIS management tools for estimating change trends in surface water quality: an application of multi-temporal land cover data

The National Oceanic and Atmospheric Administration’s (NOAA) Coastal Remote Sensing Program at the Coastal Services Center (the Center) runs a Coastal Water Quality project. The primary goal of this project is to investigate the complex nature of the impacts of terrestrial land management practices on coastal water quality and the capability of remote sensing to monitor and measure those impacts. The complex interactions between terrestrial and aquatic systems pose challenges to coastal zone managers who need to understand the relationships between land cover and water quality. The Center developed two GIS based tools to allow managers to explore these linkages using easily obtainable remote sensing data and GIS layers. The Impervious Surface Analysis Tool (ISAT) calculates the percentage of impervious surface area of user-selected geographic areas. The Nonpoint-Source Pollution and Erosion Comparison Tool (N-SPECT) examines the relationships between land cover, soil characteristics, topography, and precipitation in order to assess spatial and temporal patterns of surface water runoff, nonpoint-source pollution, and erosion. Two eras of Coastal Change Analysis Program (C-CAP) land cover data are used to model potential water quality change trends in Myrtle Beach, South Carolina.