IMPACTS OF SOIL MEDIA CHARACTERISTICS ON STORMWATER BIOFILTRATION SYSTEM PERFORMANCE

Abstract: Stormwater bioinfiltration systems can be effective options for the treatment and disposal of stormwater runoff from urban areas. However, the performance of these systems and other infiltration devices can be affected by factors such as texture, structure and degree of compaction of the treatment media. This study provides insights on media characteristics of a poorly operating biofilter facility located in Tuscaloosa, AL, along with supporting laboratory investigations. Double ring infiltrometer tests and soil compaction measurements were conducted along a large biofilter to determine the in-situ infiltration and compaction characteristics of the media. Infiltration measurements were also made during actual rain events by observing falling water levels in ponded areas. The effects of different compaction levels on the infiltration rates through the soil media were also examined during controlled laboratory column tests for comparison to the field observations. Similar tests were also conducted examining compaction effects of the media after mixing with varying amounts of filter sand to investigate restoration options. These results indicate that soil compaction results in increased bulk densities, decreased moisture capacities and has dramatic effects on the infiltration rates.

Keywords: Stormwater, bioinfiltration, infiltration, compaction