Designing & Implementing Green Infrastructure in the Metedeconk River Watershed

The Metedeconk River flows through over 40 miles of New Jersey’s woodlands, freshwater wetlands, forested wetlands, tidal wetlands, and densely developed areas before emptying into the Barnegat Bay. The river and its watershed provide drinking water from ground and surface water sources to about 100,000 homes in Ocean and Monmouth Counties.

A tributary to the North Branch of the Metedeconk River that flows directly through Ocean County Park in Lakewood, NJ. This tributary was deemed to have water quality impairments, including fecal coliform due to the Canada Goose population and high temperature due to the exposed stream channels, which lack a significant tree-canopy. The increasing amounts of impervious land cover associated with the continued urbanization of the Metedeconk River’s Watershed was also a primary cause of water quality impairments.

American Littoral Society (ALS) partnered with Princeton Hydro and local stakeholders to implement green infrastructure projects with the goal of remedying the fecal coliform and water temperature impairments in the Park’s tributary as well as improving the overall health and water quality of the Metedeconk River, its surrounding watershed, and, ultimately, the greater Barnegat Bay.

Green Infrastructure Design & Implementation Project

The project team designed and implemented a stormwater treatment train, which combined multiple green infrastructure stormwater management best management practices (BMPs) that work in unison to decrease NPS pollutant loading to the Metedeconk River and increase ecological diversity in Ocean County Park.

The project, which was funded by a New Jersey Department of Environmental Protection 2014 319(h) Implementation Grant, included four primary BMPs in Ocean County Park:
1. Installation of two Filterra curb-side tree boxes;
2. Construction of a vegetated bioretention/biofiltration swale;
3. Creation of a section of living shoreline along the banks of Duck Pond; and
4. Installation of two floating wetland islands in Duck Pond.

Filterra Curb-Side Tree Boxes

Built at street level, the Filterra™ tree box is a pre-manufactured, in-ground concrete box filled with soil media and planted with a native, noninvasive tree or shrub. It is designed to collect stormwater, absorb nutrients, and treat water before it discharges into surrounding waterbodies.

For this project, two Filterra™ tree box units were installed in the parking lot to the north of Ocean County Park’s swimming beach and each planted with serviceberry shrubs. The boxes serve to catch and treat stormwater runoff flowing from the parking lot.

Vegetated Bioswale

Unlike a traditional drainage basin that simply collects water, a vegetated bioswale uses native plants to reduce the volume of stormwater runoff, decrease total phosphorus loading, and prevent debris, sediment, and pollutants from flowing into the Metedeconk River and other surrounding waterbodies.

For this project, the team designed and implemented a .07-acre bioswale adjacent to the park’s main parking lot. Installation of the vegetated bioswale began by removing existing vegetation, excavating the ground north of the parking lot, and then regrading it per the specifications on the plans. Once proper grading was established, the basin was planted with native species including Joe Pye Weed, Blue Mistflower, Jacob Cline Bee Balm, Orange Coneflower, and Wrinkleleaf Goldenrod.

Living Shoreline Along Duck Pond

Living shorelines use a variety of native plants to filter runoff, create and improve habitat for aquatic animals, increase water quality, and protect the shoreline from erosion. Two sections of bulkhead along the North and South edges of Ocean County Park’s Duck Pond were removed so that the bank could be sloped naturally into the pond and populated with vegetation. The design serves as an additional point of stormwater collection and filtration, significantly reducing the amount of water flowing into nearby paved parking areas.

The northern portion of the living shoreline encompasses 0.06 acres and spans 100 feet along the shore. The southern portion  encompasses 0.18 acres and spans 40 feet along the shore. The living shorelines were seeded and then planted with Green Bulrush, Helen’s Flower, Switchgrass, Blue Mistflower, New England Aster, Upright Sedge, and Little BlueStem.

Floating Wetland Islands in Duck Pond

A floating wetland island is made up of a plastic matrix that is planted with water-loving native vegetation. The matrix promotes the growth of a healthy microbial community. The biofilm that develops on the plants’ roots and within the island matrix, contribute toward the uptake of nutrients within the waterbody thus improving water quality. Floating wetland islands are anticipated to remove an estimated 17.33 lbs of phosphorus and 566.67 lbs of nitrogen each year, as well as promote a balanced ecosystem through the promotion of “healthy” bacteria and plankton.

Two 250-square-foot floating wetland islands made of polyethylene terephthalate layers were populated with native wetland plants and installed in Duck Pond. The plant pockets were then filled with a biomix of soil and peat, and a variety of native plant species were planted on both islands, including: Swamp Milkweed, Upright Sedge, Common Boneset, Crimson Eyed Rosemallow, and Blue Flag Iris.

Volunteer Involvement & Community Education

Given the magnitude of the project and the high-profile nature of Barnegat Bay, community education and outreach was an essential element of the project and its long-term success. Throughout the course of the project, efforts were made to increase public understanding of the project and to encourage public input in the design of the green infrastructure BMPs and the living shoreline.

The education and outreach was a collaborative effort led by ALS, with support provided by the Ocean County Department of Parks and Recreation, Georgian Court University, Brick Municipal utilities Authority, NJDEP, and Princeton Hydro.

The team conducted public presentations and meetings, installed educational signs to accompany the water quality improvement techniques that were implemented, created a website dedicated to providing project details and updates, and invited local residents to participate in shoreline restoration and floating wetland island planting efforts.

Successful Outcome

Following the project, in-situ and discrete water quality monitoring was conducted in stream in order to assess the effectiveness of the above BMPs. The combined green infrastructure and living shoreline elements of this project set the stage for a much needed effort to reduce nonpoint source pollution loading and address waterfowl-related pathogen impacts to Ocean County Park’s lakes and the Metedeconk River. It also heightened public awareness of nonpoint source pollution and the benefits of green infrastructure measures in the abatement of water quality problems.

The project serves as a model for proper stormwater management and living shoreline creation throughout both the Metedeconk River and Barnegat Bay Watersheds.

To learn more about Princeton Hydro’s robust natural resource management and restoration services, click here. Click here to read about another stormwater management green infrastructure project recently completed in Thompson Park, the largest developed park in the New Jersey’s Middlesex County park system.

• Green Infrastructure
• Natural Resource Management
• Stormwater Management