| dc.description.abstract | Urbanization is causing increasing amounts of contaminated stormwater runoff to enter streams, rivers, and other aquatic ecosystems. In particular, nitrogen concentrations in stormwater can damage ecosystems by causing eutrophication and lowering available oxygen levels in water. Rain gardens are an efficient method of filtering stormwater before it enters ecosystems. In this study, we examined three types of soil to determine which would be the most viable for use in a rain garden in terms of nitrogen filtration efficiency, water volume output, and cost. By pouring "contaminated" water through columns of soil, we measured the flow rate and nitrogen concentrations of discharged water. Although there was no significant difference in the filtration capacity of the three soils, compost was determined to be a poor choice due to extremely low discharge flow rates. Both the sandy loam and the sand/peat mixture had comparable flow rates and filtration capacity, filtering nitrate at 65% and 79% average efficiency respectively. The sandy loam is significantly cheaper than the sand/peat mixture and is most likely the best option for use in rain gardens. | |
