GROUNDWATER QUALITY AND GIS INVESTIGATION OF A SHALLOW SAND AQUIFER, OAK OPENINGS REGION, NORTHWEST OHIO

The Oak Openings Region is a 337 km2 area located within Fulton, Henry, and Lucas Counties in northwestern Ohio and Monroe County in southeastern Michigan. The region consists of sand ridges deposited on lacustrine clay that formed during the recession of the Huron-Erie Lobes when northwest Ohio was inundated by a succession of ancestral lakes of modern Lake Erie. The shallow aquifer is comprised of fine to medium grained sand up to 12 m thick. Many driven sand point and dug wells exist in the area and local health officials are concerned about the quality of the groundwater in this aquifer. Water samples from 46 sites were collected in July 2003 and then again in June 2004. The samples were tested for a suite of parameters that included pH, alkalinity and conductivity along with other numerous inorganic and organic compounds. Results were then entered in a geographic information systems (GIS) database. The water quality results were plotted in the GIS database to show EPA drinking water maximum concentration level (MCL) and secondary regulation exceedances. Stiff diagrams of the data were also entered into the GIS database to show relative flow paths. Landuse, soil type, distance from road and septic system, along with other attributes were plotted against water quality parameters to illustrate correlations. Water quality results show no pesticides or other organic compounds for either sampling dates and show no correlation between landuse, soils, and distance from road. Distance from septic system and amount of boron show a slight correlation. The results from the current study indicate that wells in the shallow sand aquifer are not contaminated by landuse practices such as road salting and the application of fertilizers and pesticides on farmland. The results will be used by the county health boards to update current regulations regarding point and dug well construction.