ii Project Summary

The objective of this project is to show how a common AL DOT design and maintenance practice, the use of grass drainage swales, can help meet the requirements of the new Phase II Stormwater Regulations. Managing this permit can be very expensive and time-consuming. However, current drainage practices on many AL DOT transportation corridors likely meet the objectives of the conservation design strategy of the permits. This project shows the water quality and drainage benefits of grass-lined drainages. This will result in significant time and cost savings for AL DOT managers. An important element of the Phase II NPDES Stormwater Regulations is the reliance and promotion of conservation design elements. Agencies, including transportation departments, will be required to emphasize the use of stormwater drainage practices that help reduce the discharges of pollutants and excessive runoff volumes, while maintaining successful drainage objectives. The federal guidance emphasizes the use of “soft ” controls over historically expensive stormwater treatment options. These include the use of grass swale drainages, minimizing the amount of paved areas, and routing runoff from paved areas to specially constructed infiltration areas. In Alabama, AL DOT already uses grass swale drainages in many suburban and rural areas. The objective of this project is to document the stormwater quality attributes of these existing drainage system elements under local conditions so tha