Impacts of a rural subdivision on groundwater: results of a decade of monitoring

Understanding how rural subdivision developments using onsite septic systems impact groundwater quality and quantity is important for land-use decisions. In 1998, an unsewered subdivision near Sun Prairie, WI became part of a long term groundwater monitoring project. Prior to being converted to residential lots, the area consisted of agricultural land, woods, and a wetland. Investigations in 2002 and 2005 showed that groundwater beneath the site had been impacted by nitrate and atrazine from previous agricultural use, and that significant temporal and spatial variation in groundwater quality occurred. One of these studies detected three wastewater indicator compounds in septic drainfield effluent, but none of the compounds were detected in groundwater.The present study is a long-term follow-up to the previous studies and was designed to examine the impact of septic systems after a longer period of use. In addition, new technology allowed the analysis of numerous wastewater indicators such as human viruses and artificial sweeteners