Discussion

Rain gardens play an important part in preventing runoff into our waterways by absorbing and filtering the contaminated water before releasing it into our freshwater ways. Studies have indicated that "up to 70 percent of the pollution in our streams, rivers and lakes is carried there by runoff", additionally, rain gardens provide new habitats for wildlife, and they are a great place for native plants which form deep roots to channel the water and provide soil stability (Steeb). These factors demonstrate the importance of runoff and therefore rain gardens in maintaining our environment. 

Our analysis and investigation demonstrated an insignificant difference between the old and new soil conditions for all factors except genetic biodiversity. Our data shows the new soil condition has a statistically significantly higher average richness and diversity but a lower evenness than the old soil condition. We found that our new soil condition had higher levels of Pseudomonas and Sphingomonas. Sphingomonas are found in soils contaminated with pollutants due to their unique function of degrading pollutants. Pseudomonas play an important role in soil diversity. This information provides insight to the biodiversity and health of the soil in new rain gardens compared to old rain gardens, which could be used to determine whether the old rain garden is still as effective as the new one. This knowledge could have a significant impact on how communities maintain and design their rain gardens to have the greatest positive impact on the environment and water pollution.