Effect of pavement and traffic characteristics on storm water quantity and quality
This research aims to analyze the current capacity of detention basins and swales in sites located in San Antonio to store the storm water runoff as of now and when the full development of the watershed takes place. Future development of watershed areas is a significant factor in designing the capacity of basins and swales because it will increase the storm water runoff volume by decreasing the infiltration. It analyzes the capacity of basins required to meet the current peak inflow and future peak inflow of storm water runoff after the full development of watershed areas under various degree of rainfall such as average daily rainfall, maximum daily rainfall, and extreme rainfall event with the highest daily rainfall in San Antonio in ten years. The swales should be designed to convey the peak storm water inflow of the 10-year rainfall – the rainfall of the size that is expected to occur once every 10 years --according to storm water manual of San Antonio, hence this research analyzes the capacity of swales required to meet the current peak inflow and future peak inflow after full development of the watershed areas due to the 10-year rainfall and extreme event of 100-year rainfall. If the design capacity of the swale withstands these rainfalls, then the swale is assumed to have adequate capacity to meet the requirement for average rainfall of San Antonio. The watershed areas that contribute storm water runoff to the basins and swales were determined using Google Earth Pro. This was followed by analyzing the impact of pavement properties such as pavement area, slope, age, the Average Annual Daily Traffic (AADT), and vehicular speed to each site's storm water runoff volume and quality. The major pollutants in the storm water runoff were analyzed and the efficiency of detention pond and swales were determined and analyzed by comparing the concentration of influent and effluent pollutant loads.