Christianson, R, PE, PhD and Fraley-McNeal, L. 2016.Influence of Stormwater Infiltration Practices on Surrounding Structures. Watershed Science Bulletin, February 2016. Center for Watershed Protection, Ellicott City, MD.

Infiltration areas for stormwater management have the same hydraulics as natural groundwater recharge and infiltration areas designated for aquifer storage and recovery projects. Work on infiltration and groundwater movement has been going on for years, making the available knowledge base fairly wide. Differences, however, arise in the intended use of the practice/area. While the goal of groundwater recharge is to promote a more sustainable and cleaner groundwater source (possibly water banking for dry times), the goal of stormwater infiltration practices is to harvest stormwater (leading to reduced discharge volume and enhanced water quality) in order to meet stormwater regulations. For stormwater practices, concern about the appropriate design criteria generally stops at sizing the structure to meet pollutant removal goals, maintain groundwater recharge, pass extreme floods, and reduce downstream channel erosion. Investigating the impact on surrounding structures like parking lots and buildings, through exploration of groundwater mounding, provides in-depth understanding of cautions and considerations for stormwater infiltration practices. An example of a stormwater infiltration site in Mission, Kansas is provided in this paper. At the Mission site, Visual Bluebird groundwater modeling software was used to identify potential areas of concern for groundwater mounding. In addition to the modeling approach, several guidelines are also provided to help identify areas with a higher likelihood for groundwater impacts following the case study.