Impacts of Onsite Stormwater Management on Different Residential Communities

Urbanization expanding the impervious areas such as rooftop, building top, parking area, street and road has increased the stormwater runoff volume, which was used to infiltrate into undeveloped green space. Thus, the city of Atlanta promoted projects to separate the combined sewer system in the city area as well as to expand the carrying or storage capacity of combined sewer lines. However, still the stormwater runoff as a non-point source contaminates surface water and consumes additional resources for its treatment. Low impact development(LID) options such as green landscaping and rainwater harvesting have been remarked due to their potential controlling the stormwater on-site and even enabling people to use rainwater for domestic purposes. Thus, the rainfall volume distributing to runoff, initial abstraction and harvesting was quantified depending on the application of rain garden, rooftop harvesting and/or surface runoff harvesting. Also, the stormwater distribution profile was investigated for two residential communities, which have different sizes of private yard, house, street and open space. The application of the options reduced the runoff generation at least by 40 % even in 100-year return period rainfall intensity. The harvesting potential improved the water scarcity issue of the city which is close to high limitation into the condition close to medium level. The city can save greater than $1.6 million/year and the city's residents can save up to $38.5 million/year and, additionally, the property value increases due to the aesthetic value of green landscaped communities.