Infiltration Testing
From large to small scale infiltration studies, PS&R conducts infiltration testing and soil characterization in accordance with the Pennsylvania Stormwater Best Management Practices Manual, Appendix C. Staff geologists or engineers prepare detailed logs of the soil profiles as well as the depth to groundwater, seasonal high water table, bedrock or other limiting zones observed in the test pits excavated in potential BMP areas. If suitable conditions are present, a double-Ring Infiltrometer ( 510HD) is installed in an adjacent test pit at the appropriate depth to measure the infiltration rate. The infiltration test results are then utilized to determine the optimum locations for stormwater BMP structures for a proposed project site.
Infiltration Testing Background
- Infiltration tests estimate the rate at which runoff will infiltrate into the subgrade of stormwater facilities installed in undisturbed, native soil.
- Infiltration tests should be performed across the proposed development area prior to the development of the site grading plan. This provides the opportunity to install LID (Low Impact Development) facilities on optimal soils and geology. If buildings are proposed on slower infiltrating soils and stormwater facilities sited in faster infiltrating soils, builders can plan their sites to improve stormwater management, prevent flooding, address water-quality issues and decrease the cost of the on-site stormwater management facilities.
- The information obtained from the infiltration test studies can be used to answer three important questions. Is the site suitable for an infiltration facility? Can the site be developed to meet water quality standards? What size of low-impact development (LID) facility should be installed?
