An Evaluation of the Effect of Stormwater Treatment Ponds on Wetland and Stream Quality Indicators
Date of Award
Master of Science
Timothy J. Ehlinger
Timothy J. Ehlinger, James A. Reinartz, Peter O. Dunn
Modifications of land cover in urban areas are leading to hydrological, physiochemical and subsequent biological disturbances in the receiving aquatic ecosystems. Resulting in damage of the limited quantity of available freshwater. Based on the recognition of the value of natural wetlands in water quality improvement, constructed wetlands have been widely used for water treatment, to remove fine pollutants from catchment runoff also to control increased surface runoff from urbanization. The hypotheses of the study was that the surface water quality would improve while the sediment quality would vary moving from up-gradient to down-gradient through the interconnected wetlands, relative to precipitation, discharge rate and season. The interconnected wetlands in Pike River watershed (Racine, WI) were chosen for the study. Water quality (physical characters and nutrients) and sediment studies were performed in these three interconnected wetlands and in the stream as well. Physical parameters (including pH, specific conductivity, dissolved oxygen, turbidity) and nutrient levels (nitrogen, phosphorus) were analyzed from the water. Sediment bioassays were performed with the plant species Sinapsis, Lepidium, and Sorghum and with the invertebrate Heterocypris as an indicator species. Also, Thamnocephalus was used as an indicator for the pore water bioassay. Results showed strong indication of water quality improvement by phosphate reduction towards the down-gradient wetland, high specific conductance, turbidity and Low dissolved oxygen partly in the up-gradient wetland. Although there were some exceptions in the results, but its important to realize that these wetlands are just 10 years old and may not have their biological potential at the fullest like natural wetlands. Another important finding of the study was that the stream also performed in a comparable fashion with the wetlands. These findings suggest that a functional interconnected wetland system can discharge less polluted fresh water to its connected water body.
Ghosh Roy, Subhomita, "An Evaluation of the Effect of Stormwater Treatment Ponds on Wetland and Stream Quality Indicators" (2012). Theses and Dissertations. 198.