Urbanization And Its Effects on Hydrology, Water Quality, And Fish Communities in the Big Darby Creek Watershed, Ohio

Abstract

The Big Darby Creek in Ohio is one of the more ecologically diverse rivers in the United States. The watershed is currently experiencing urban development pressure, and therefore, the purpose of my research is to understand how urbanization is affecting hydrology, water quality, and fish communities along the Big Darby Creek. I determined that the amount of developed land area has increased 8.06% from 2001 to 2014. Discharges between the study years did not differ, but the Richards-Baker Flashiness Indices increased 31.3%. I compared mean ambient water quality parameter concentrations for ammonia, “nitrates and nitrites,” nitrites, total Kjeldahl nitrogen, total phosphorus, and total suspended solids. Mean ambient nitrites, total Kjeldahl nitrogen, and total phosphorus concentrations declined 17.7%, 25.5%, and 57.5% respectively. I used mean ambient water quality parameter concentrations to calculate weighted stressor values for each species of fish for each water quality parameter for 2001 and 2014. I correlated fish species with a weighted stressor value in the bottom 20th percentile to each water quality parameter in each study year. I found significant correlations between the quantity of sensitive fish species to total suspended solids and “nitrates and nitrites” for both study years and total phosphorus in 2014. The number (517) of sensitive species in 2001 and 2014 did not differ when all chemicals were compared, but there were 1.09 times more in 2014. 2014 had a greater quantity of sensitive fish species than 2001 when I only analyzed the data for total suspended solids and “nitrates and nitrites.” Shannon-Weiner Diversity (SDI) Indices increased between 2001 and 2014 while species evenness scores did not differ. Additionally, SDI indices were negatively correlated with study site. When I classed fish species into feeder groups and compared them, insectivore quantities increased from 63% to 74% between 2001 and 2014. Overall, my research shows improvement in water quality and ecological diversity on the Big Darby Creek despite ever present and increasing urbanization.