Impacts of Onsite Stormwater Management on Different Residential Communities

摘要

Urbanization expanding the impervious areas such as rooftop, building top, parking area, streetand road has increased the stormwater runoff volume, which was used to infiltrate intoundeveloped green space. Thus, the city of Atlanta promoted projects to separate the combinedsewer system in the city area as well as to expand the carrying or storage capacity of combinedsewer lines. However, still the stormwater runoff as a non-point source contaminates surfacewater and consumes additional resources for its treatment. Low impact development(LID)options such as green landscaping and rainwater harvesting have been remarked due to theirpotential controlling the stormwater on-site and even enabling people to use rainwater fordomestic purposes. Thus, the rainfall volume distributing to runoff, initial abstraction andharvesting was quantified depending on the application of rain garden, rooftop harvesting and/orsurface runoff harvesting. Also, the stormwater distribution profile was investigated for tworesidential 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-yearreturn period rainfall intensity. The harvesting potential improved the water scarcity issue of thecity which is close to high limitation into the condition close to medium level. The city can savegreater 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 landscapedcommunities.