Analysis Of Pervious Concrete As A Stormwater Management Tool Using Swmm Modeling

Stormwater runoff occurs when precipitation flows over the ground. Increase in impervious land cover due to urbanization causes excess stormwater runoff and affects the quantity and quality of water bodies. The use of low impact development (lid) controls is highly recommended to reduce the excess volume of stormwater runoff. Lid controls include infiltration techniques such as pervious pavements, evaporation, and storage techniques to reduce the volume of runoff. In this study, an analysis is done for the performance of pervious concrete pavement located at the University of Mississippi Law School parking area. The law school was constructed in 2010 and is adjacent to a privately owned recreational pond. Prior to the construction of the law school, runoff from the area, which contained student housing and parking lots, contributed excessive water and sediments to the pond. The university then constructed pervious concrete pavement to reduce the runoff. However, there is a high volume of runoff from the law school area going to the pond, which leads to the hypothesis that the pervious concrete parking lot is not performing as planned. Multiple in-place infiltration rate tests, using the astm c1701/c1701m-09 standard test method, were conducted at different locations to evaluate the effectiveness of the pervious pavement. The area was then modeled using the epa stormwater management modeling tool (swmm) to quantify the volume of runoff that can be expected from different intensity storms with various pervious concrete pavement area coverage and infiltration rates. Based on the infiltration rate test results the average infiltration rate of the impervious pavement is 45 mm/hr, which is less than the desired rate. The modeling results show pervious concrete is 25% more effective for a low intensity, long duration storm (178-mm in 24-hr) than for a high intensity, short duration storm (209-mm in 4-hr). 21% to 45% volume of runoff can be reduced by increasing the area of pervious concrete pavement coverage by 30%. However, the same volume of runoff cam be reduced by maintaining the desired infiltration of pervious concrete pavement