Long-Term Subsurface Monitoring of Storm Water Infiltration for Groundwater Recharge

The USEPA and many states have recently issued regulations and permits encouraging the capture and infiltration of storm water runoff to reduce the volume and peak flow of surface runoff, and to augment groundwater supply. These regulations apply to a wide variety of land uses, including industrial sites. Although these new regulations will undoubtedly increase storm water infiltration and groundwater recharge, there is a general lack of research to indicate whether this strategy will eventually result in degradation of groundwater quality. This paper is a case study of long-term (up to six years), comprehensive subsurface monitoring at six infiltration sites in southern California that begins to address this important issue. Results to date suggest that properly designed and implemented storm water infiltration poses little risk to groundwater quality.