Simulation Modeling Of Hydropower Impacts On Dissolved Oxygen In The Upper Ohio River Basin PDF Download

Abstract: The potential changes of dissolved oxygen concentrations caused by combined sewer overflows (CSOs) are an important consideration before and after dam removal in many urban rivers. In central Ohio, removal of a 2-m-high dam is planned in Columbus for the fourth-order Lower Olentangy River, which has several major CSOs. Two simulation models were developed, using STELLA® 9.1.4, an icon-based dynamic systems modeling software, to investigate the interactions of hydrology, water quality, CSOs, and dam removal on the Olentangy River reservoir before the Fifth Avenue Dam. The first simulation model, focusing on daily dissolved oxygen (DO), was created to predict DO changes with the pollution of CSOs before and 120 hours after dam removal. Field DO data in 2009, 2011, and 2012 were used to calibrate and validate the model. The second simulation model, a weekly water quality model, was created to simulate one-year streamflow, gross primary productivity (GPP) and DO changes before dam removal and to predict long-term water quality changes 2 years after dam removal. Field streamflow and water quality data in 2004 and 2009 were used to calibrate the model. The results from both field data analysis and model simulations suggest that large differences existed in water quality between base flow and flooding periods. The water quality of the Lower Olentangy River will be impacted immediately after dam removal. DO concentrations will continue to be significantly impacted by CSO discharges even after dam removal.