Impact of soil media in raingardens used for control of urban stormwater

Three different types of soil media suitable for rain gardens were analyzed in the laboratory in order to evaluate the impact of soil type on stormwater quality. Synthetic parking lot runoff was used to dose laboratory-scale columns containing different media: 100% sand; 50% sand + 50% compost; and 50% sand + 50% peat. The effluent samples from all the columns were analyzed for turbidity, conductivity, pH, COD, chloride, nitrate, phosphate, and sulfate ions. The soil samples were analyzed for plant nutrients, cation exchange capacity, and select cations. The column study showed that the sand + compost media had the best combination of ability to remove contaminants and support the growth of rain garden plants.