Establishing GIS Land Use/Land Cover Indicators for Assessment and Monitoring of Marine Ecosystem Health

Human population growth and land cover change in coastal areas increase the sources of anthropogenic-induced pollution, microbial pathogens and potential transport of these contaminants to important nearshore habitat, shoreline public use and access areas. Impervious surface is a well-documented indicator of the consequences land development has on the ecological integrity of aquatic ecosystems (Alberti et al., 2004; Arnold and Gibbons 1996). While most existing studies have focused on the relationship between watershed urbanization and the associated biotic conditions in streams (Booth et al., 2002), there have been some recent investigations that consider impervious surface and development impacts to coastal areas (Holland et al., 2003; Lerberg et al., 2000; Fulton et al., 1993). This project is motivated by the need to better integrate the results of landscape-scale drainage basin analysis into comprehensive zoning, land use regulations, and storm water and shoreline planning.

The overall goal of this project is to test apply a GIS landscape metric methodology to complete spatially-explicit characterizations of select marine drainage basins in Washington’s Puget Sound. Specific objectives include: 1) hydrogeomorphologic delineation of marine drainage basins, including shoreline surface flows and ground water seeps (Alberti and Bidwell 2005); 2) assessment of drainage and drift cell system functions; 3) a prioritized list of natural resource sites for preservation and restoration; and 4) identification of the most appropriate areas to implement storm water retrofitting and low impact development (including clustering and storm water Best Management Practices) to most effectively accommodate flood and geologic hazard conditions, protect water quality and preserve and restore habitat.

The project objectives will be addressed through application of a geospatial analysis of land cover patterns from remotely sensed imagery (color infra-red, multi-spectral and aerial photography) together with water quality and habitat survey data to assess the status of marine habitat and function. The characterization relies on measures of land use change that are indicative of ecological stressors such as alterations in physical habitat, modification of upland vegetation and release of contaminants. The land cover metrics to be evaluated (such as deciduous vegetation patch size, aggregated impervious patches per unit length of shoreline) and their relationships to ecosystem function (e.g. transport of storm water runoff) have been defined or estimated through empirically based studies and process model results available in the scientific literature.

Based on a review of the most recent scientific literature on non-point source pollution and land use impacts to marine systems, we will develop a table of indicator geospatial metrics, including a list of source data necessary for their application. The indicator metrics will be developed and applied to a selection of pilot study areas in the Puget Sound, resulting in a final report, interpretive maps and tables demonstrating this application. The results will be presented in a Powerpoint-based web module and at one public forum for local governments.