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ANALYSIS OF LANDSCAPE AND WATER QUALITY IN THE NEW YORK CATSKILL - DELAWARE WATERSHED (1973-1998)
Citation:
Mehaffey, M H., T G. Wade, M S. Nash, AND C M. Edmonds. ANALYSIS OF LANDSCAPE AND WATER QUALITY IN THE NEW YORK CATSKILL - DELAWARE WATERSHED (1973-1998). Presented at International Congress on Ecosystem Health, Sacramento, CA, August 15-20, 1999.
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
The primary goal of this study is to improve risk assessment through the development of methods and tools for characterization of landscape and water resource change. Exploring the relationship between landscape pattern and water quality in the Catskill-Delaware basins will improve understanding of environmental risk and help maintain New York City's drinking water supply system. Currently the city is trying to decrease the threat to its quality of water through 'the development and implementation of a long-range watershed protection program. Under the agreement, the State Department of Environmental Conservation issued a permit to acquire land through outright purchase and conservation easement. Landscape indicators believed to impact drinking water quality were calculated for all sub-basins in the Delaware/Catskill watershed using land cover derived from 1989/1991 landsat TM imagery. All available water quality data was collected for streams and reservoirs in the Catskill-Delaware basins from 1986-1994. The main source for chemical and physical water quality parameters was the EPA's storage and retrieval data base (STORET). The New York State Department of Conservation supplied a separate database containing benthic measurements from 1986 to 1997. Correlations were conducted at the scale of the sub-basin between landscape indicators and water quality parameters There were negative correlations between forest and the water quality parameters chloride, pH, silica, and nitrate nitrogen. Urban and crop land use patterns, particularly on steep slopes and within the riparian area, had weak positive correlations with chloride and nitrate nitrogen, while pasture tended to be more strongly related to pH and silica levels. A step-wise regression analysis was conducted on 25 sampling stations for which the proportion of forest, urban, pasture and crops had been calculated 100 and 500 meter upstream of the site. The interactions between landscape indicators were found to be more important in predicting water quality than any single land use type. These results suggest that maintaining the quality of New York Cities' water supply will require the evaluation of multiple landscape indicators in order to target areas in need of protection or restoration.