Sustainable Stormwater Management: Infiltration vs. Surface Treatment Strategies

Stormwater managers are increasingly faced with the need to address many potentially-conflicting issues as part of their activities, ranging from flood prevention to protection of downstream habitat. New urban development philosophies, such as low impact development, no adverse impact, water-sensitive urban drainage systems, etc., establish goals similar to other professions – Do No Harm. This is addressed often through criteria such as maintaining pre-development hydrology to the maximum extent practicable after development with treatment provided to reduce pollutants to their pre-development level. These new management plans incorporate both infiltration and surface treatment/discharge into the development.

A series of flowcharts were developed to aid stormwater managers in stepping through the process of selecting an appropriate management/treatment technology that meets both the low-impact goals and the regulatory requirements. These charts refer to the specific document sections that address the issues of concern that should be considered when selecting appropriate stormwater practices. Appendices were developed to provide supporting information for users not familiar with the terminology or the methods and supporting literature.  

This work has been based on the literature and guidance documents developed around the world. Surface-treatment technologies such as detention and filtration have a long history with much literature published about them. They are better understood than the infiltration practices currently gaining favor. Therefore, several chapters are devoted to the concerns associated with selecting infiltration.