Stormwater filtration and infiltration are two sediment control processes to manage surface runoff. Filtration systems are designed to remove suspended sediments by passing water through porous media filters—often consisting of sand, soil, or gravel—or vegetative filters like grassed swales.1,2,3 These systems have widespread applicability; however, filtration systems are less effective when capturing finer solids such as highway runoff pollutants.4
Infiltration systems work by temporarily storing runoff, before allowing it to infiltrate into the ground.4 Stormwater infiltration allows for pollutant removal, slows runoff velocity, and decreases the volume of runoff.5,6 Examples of infiltration designs include detention basins, underground infiltration systems, permeable pavements, and infiltration trenches.7
How it Helps
Combination of Measures:
Infiltration systems may require additional stormwater management solutions to assist in runoff storage and sediment removal.5 Developers and planners should communicate with engineers and other drainage and waste removal experts before implementing infiltration systems in a community.
There are certain factors that need to be assessed before filtration or infiltration systems can be implemented to determine compatibility with the surrounding environment, including existing infrastructure, soil types, runoff flow patterns and volume, and other characteristics.
1) Surfside Beach, South Carolina’s Stormwater Mitigation Solutions
Surfside Beach has implemented several stormwater mitigation solutions, including using infiltration pipe and deep sump catch basins. The town has utilized other approaches, including public education and street sweeping, to greatly improve their water quality.