First Gravel Wetland in Connecticut!    

In 2012, NWCD assisted in the installation of the first gravel wetland in Connecticut. A barn manufacturing company applied to the town of Morris to create a commercial operation on a developed site, which proposed to add approximately one acre of impervious surface, requiring a primary stormwater treatment practice.

     Subsurface Horizontal Flow Gravel Wetlands, ‘Gravel Wetlands’, function as biological filters similar to bioretention structures. However, instead of moving polluted stormwater vertically through one or two feet of soil media, a gravel wetland filters water horizontally through roots, soil, and gravel across 30+ feet. An anaerobic environment, combined with a long filter path, makes gravel wetlands extremely efficient at pollutant removal.

     Gravel wetlands are one of many stormwater treatment measures considered for a Low Impact Development (LID) project. One of the principle goals of LID is to use structures that mimic natural systems to treat polluted stormwater where it is generated. Gravel wetlands have a unique ability to strip out a broad spectrum of pollutants captured in runoff, while maintaining a relatively compact structure. This makes them an ideal primary treatment measure for both new development and retrofitting developed areas.

     All development have impacts on the environment that need to be balanced with a property owner’s wishes. LID is a paradigm that helps the land use management community minimize environmental degradation. There is well-documented evidence that developing land using LID principles and standards is more cost-effective, more efficient at water quality and wetland protection, and more attractive as compared with conventional development practices.

     Comprehensive documentation of gravel wetlands can be found at the University of New Hampshire’s Stormwater Center, where they have designed, built and treated these systems for many years.

Morris Gravel Wetland Photo Gallery