Assessing the Impact of Urbanization on White River Water and Sediment Geochemistry in An Agricultural Watershed

Increased urbanization in the United States and the rest of the world, has led to more research on the effects it has on the local ecology. Urbanization can be defined as the creation of impervious cover in areas previously covered by forest, grass or farm lands. Small increases in impervious cover can cause noticeable changes in stream chemistry. The goal of this study is to quantify the impact of smaller industrial cities on water and sediment geochemistry in a largely agricultural watershed. The study area is in east-central Indiana along the west fork of the White River and includes the cities of Winchester, Muncie and Anderson. This area is dominated by agriculture and the impact of cities in the region on water chemistry has not been studied. To assess this impact, sampling sites were selected up- and downstream of the three cities to characterize White River water chemistry before and after it flows through the cities and sewage treatment plants. Sampling was done over the course of one year to obtain samples characteristic of high and low flow river conditions. Samples were analyzed for major cation and anion concentrations as well as total suspended solids. Background sites unaffected by urbanization were sampled for comparison. Metals data was also obtained from water and sediment in the study area. Results show that sediment load, on average, increases on the downstream side of these cities. Initial chemical analyses show that major cations and anions, Na+, K+, NO3-, SO42- and Cl-, have distinct spikes in concentration on the downstream side of the cities, as well. Na+ and Cl- are specifically linked to human and urbanized activity, and were up to four times higher downstream of the urbanized areas.