ASSESSMENT OF TEMPORAL VARIATION IN STREAM WATER QUALITY DUE TO LAND USE CHANGES IN THE MID-OHIO RIVER WATERSHED DURING 1977-2003

The objective of the research was to determine changes in land use/ land cover and the affect on water quality in the Mid-Ohio River Watershed area during 1977-2003. Satellite images were classified into land use/ land cover maps, and maps were also acquired from the United States Geological Survey (USGS). Water quality data was collected from the USGS and the Environmental Protection Agency (EPA). Trends in nutrient concentrations in water were researched as well as land use changes.

The USGS and EPA water quality data were both useful for different reasons. The water quality data collected from the EPA (STORET and Legacy data) was abundant. Water quality stations plotted from the EPA data had numerous locations in the study area. The abundance of data was useful to find locations of water quality stations which occurred solely in forest, urban, or agricultural areas. The water chemistry could then be compared for each of the areas using Archydro to delineate watershed areas for the stations. This research helped to determine relationships with water quality and land use, such as higher chloride concentrations in urban areas. The USGS (NASQAN and HBN data) was also useful since the water quality sampling data was continuous from 1977 – 1995, and the station locations were static during this period. The USGS data was used to plot graphs showing changes in concentrations of nutrient constituents through the years.

Land use/ land cover data (LULC) were derived from LANDSAT imagery provided by Earthsat for NASA, and was also collected from the USGS. The changes in forest were determined from both sets of imagery. The USGS LULC was used to find changes in forest from 1977 – 2001, while the LULC maps created were used to find changes in forest from 1988-1999. Changes were then compared for the years which overlapped. Both sets of change detections showed that forest increases from 1988-1999. The USGS LULC change detection also showed a decrease in forest from 1977-1992.