Community partnership reaches milestone for water quality improvements

A community partnership designed to reduce pollution runoff into the Little Assawoman Bay will be completed with the construction of a new pond and wetland near Sea Colony, with a new right-turn lane off Route 1 also being constructed.

Construction was set to begin March 2 on an innovative stormwater treatment facility located at the intersection of Coastal Highway and South Pennsylvania Avenue near Bethany Beach, South Bethany and the Sea Colony high-rise condominiums.

The work is the final project of a water-quality master plan for the Anchorage Canal drainage area, developed in 2010 by a community partnership led by the Delaware Center for the Inland Bays. It will include a pond and wetland designed to remove pollution from stormwater runoff that flows to South Bethany’s Anchorage Canal. The facility will include native vegetation that is intended to help with pollution removal and beautify the area.

The South Pennsylvania Avenue northbound slip ramp off of Coastal Highway will be closed to vehicles and made into what the partnership described as “a safe and attractive walking and bike path.” A new right-turn lane will be created at the existing intersection, they said.

South Bethany’s canals, which flow to Little Assawoman Bay, are considered highly polluted by excessive amounts of nitrogen and phosphorus, much of which comes from stormwater runoff. The canals are poorly flushed, and the excess nutrients cause heavy algae blooms in warmer months and low oxygen levels in the water that can harm fish and other aquatic life.

Anchorage Canal, the northernmost of the South Bethany canals, receives runoff from a 100-acre drainage area that includes nearly a mile of Coastal Highway, the Sea Colony condominiums, and homes and businesses on either side of the highway. As a result, the canal has been particularly stressed by runoff pollution, they said.

To address the poor water quality, South Bethany, Middlesex Beach, Bethany Beach, Sea Colony, DelDOT and the Center for the Inland Bays have worked together for a decade to implement a Pollution & Stormwater Control Strategy for Anchorage Canal Drainage Area that identified 25 stormwater retrofit projects.

Bioretention facilities installed in the median in South Bethany in 2012

Bioretention facilities were installed in the median of Route 1 in South Bethany in 2012 to help address runoff into the canals. A new project will complete the larger effort by reducing pollution in runoff into the Anchorage Canal.

Those include a variety of wet swales, bioretention facilities, infiltration trenches and rain gardens that have been built through grant-funded projects managed by the Center and its partners. The goal is to remove at least 40 percent of the nitrogen and phosphorus that enters Anchorage Canal from the drainage area. The new pond and wetland built this spring will complete implementation of this master plan.

“This is a significant achievement for clean water,” said Marianne Walch, the Center’s Science & Restoration coordinator. “The Anchorage Canal stormwater initiative has been a great demonstration of how communities, government agencies and nonprofit organizations like the Center can work together to achieve important water quality goals.”

John Gilbert, speaking on behalf of the Sea Colony Recreation Association, which helped fund the project, noted, “It’s been a pleasure to work with the Center for the Inland Bays, the local beach community and DelDOT, as well as our consultants, in developing this important project. … It serves two key objectives by improving pedestrian safety and removing pollutants from runoff before the water goes into the canals and bay.”

Design and construction of the project were funded by DelDOT’s Transportation Alternatives Program, with a 20 percent match from the Sea Colony Recreation Association. The Center sponsored the partnership.

The first phase of construction beginning March 2 will involve a detour of the right-turn lane on Pennsylvania Avenue. Motorists are also being cautioned that access to Pennsylvania Avenue from Coastal Highway will at some point in the spring only be from the new turn lane. Construction of the project is expected to be complete by mid-June.