As part of the Regional Wastewater Management Plan, Cape Cod Commission staff examined green infrastructure (GI) opportunities including dredging, inlet widening, and aquaculture. However, additional data are needed to establish the percent nitrogen removal that can be attained using green infrastructure solutions. The Commission focused a US Environmental Protection Agency (EPA) technical assistance grant on the use of various green infrastructure technologies to reduce nitrogen from groundwater and stormwater sources within Environmental Justice (EJ) communities, resulting in proposed projects in Barnstable and Yarmouth. Technical assistance was provided to the Cape Cod Commission through EPA’s 2012 Green Infrastructure Community Partners Project to develop conceptual designs for GI projects in the Lewis Bay/Parkers River watersheds. The overall intention of the project was to identify areas within EJ communities where pollutants from stormwater may be addressed closer to the source and often at a reasonable scale (size) and cost. It also offers greater opportunities for re-establishing connections to green open space infrastructure, providing air quality benefits, access to open space, recreational opportunities, and re-creating the human-environment connection. Many of the vegetative options are transferable among similar environments and can be taught to EJ community youth to provide them with construction and landscaping skills and improved job opportunities for building and maintaining green options and environments. Such projects are needed throughout the region and could provide sustainable solutions to areas vulnerable to excessive runoff, sea level rise and wind driven storms.
As part of the project, a screening process was refined utilizing a siting criteria matrix to identify areas of opportunity for green infrastructure practices. The green infrastructure practices identified and assessed as part of the screening process were specifically selected for nitrogen reduction capabilities and included constructed wetlands, phytoremediation, enhanced bioretention and many others. Application of the screening process resulted in the selection of eight high-opportunity sites for green infrastructure placement. These sites were investigated in more detail through a field site assessment that evaluated physical, public outreach, economic, water quality, and constructability considerations. The project team presented the screening process and the site opportunities to a group of local stakeholders from Barnstable and Yarmouth. This group of stakeholders, Commission staff, and consultants collectively selected two sites to advance to conceptual designs. An advanced bioretention system was designed for an elementary school in Barnstable and a bioretention/phytoremediation area was designed for a proposed marina site in Yarmouth. In addition, conceptual plans and details, an analysis of the regulatory pathway, and cost estimates for the two sites were also developed.
Presented at the New England Water Environment Association (NEWEA) conference, January 2014
|» View the Photo Gallery:|| Cape Cod Commission (CCC) staff launched a research project in 2012 focusing on the use of trees to mitigate excess nitrogen in groundwater. The process involved phytoremediation, which is the use of plants to clean up soils. Phytoremediation has been shown to be a cost-effective, aesthetically pleasing, and environmentally conscious method of cleaning up contaminated groundwater. |
In June 2012, a graduate research student and several CCC staff members installed test cells at the Barnstable Water Pollution Control Facility (WPCF) to learn the potential of phytoremediation as one among a set of possible green infrastructure options to lessen the impacts of wastewater on Cape Cod's groundwater and estuaries (see PHOTO ALBUM). Three species of trees — two hybrid poplars and one willow — were planted as saplings in nine “test cells.” Bi-monthly water samples were taken to determine how well the trees remediate nitrogen, phosphorus, and heavy metals from the facility’s effluent. The Commission staff compiled the final report (above link) after having received all the water-quality sampling results from the lab at the UMASS/Dartmouth School for Marine Science and Technology. In January 2013, the staff moved the materials to the Alternative Septic System Test Center run by the Barnstable County Department of Health and Environment. There, the trees will continue to be dosed with effluent and results will be measured on site.
Special thanks to the Town of Barnstable, Ecolotree, and Cape Cod Aggregates for their assistance with this project.
Special Projects Coordinator,