Watershed Plan Case Study

Long Island Watershed

Shinnecock Bay, Long Island

Estuaries throughout Long Island have long supported a vibrant shellfishing industry, but significant changes in land use and development in recent decades have increased inputs of bacteria, nutrients, and sediments, decimating eelgrass beds and shellfish populations. As a result of the Town of Southampton’s targeted watershed planning and implementation efforts, Shinnecock Bay, located on the south fork of Long Island, is experiencing improvements in coastal water quality and habitat and a related resurgence of bay scallops and other shellfish.

Recognizing the importance of wetlands in protecting water quality and habitat, the Town of Southampton adopted a Wetlands Protection Law in 1993. The primary goal of the law is to restore wetland and buffer areas as mitigation for proposed new development or expansion. The wetland ordinance requires a permit for projects that include filling, digging, dredging, or other activities associated with new construction, installation of fences, vegetation pruning, demolition, and environmental testing within wetlands and specified wetland buffer zones.

Southampton has made significant strides in mitigating stormwater runoff by identifying key problem areas and implementing best management practices to remove sediment and other pollutants from storm water. This includes an effort to “peel back” roadways that end at the shore by creating naturalized buffers of beach grass and shoreline vegetation at road ends. In an effort to improve the ecological functions of degraded wetlands, the Town has restored the natural hydrology of several marshes by removing dredged materials and replanting those areas with native wetland vegetation.

The Town has also been successful in acquiring lands to preserve sensitive coastal and wetland areas. The Town of Southampton enacted a Community Preservation Fund which places a two percent tax on all land transfers within the Town. Revenue generated from the tax is used to purchase sensitive lands that provide critical ecosystem functions.

This case study appears in Chapter 6 of the Watershed Plans Guidebook.

Watershed-Based Stormwater Management on Eastern Long Island 

The Suffolk County Department of Health Services is implementing stormwater management plans in four pilot watersheds on eastern Long Island to address runoff from farms, villages, and commercial properties. The project involves identifying potential stormwater retrofits in each watershed and developing a ranking system to identify the top sites for priority construction. Factors considered in the ranking system include the potential reductions in nitrogen and bacterial loading, construction cost, land ownership, permitting constraints, construction and maintenance access, maintenance burden, habitat potential, and supplemental public benefit (e.g., educational opportunity). Project sites were scored and ranked to develop a "short-list" of projects for immediate implementation. This ranking will be used to focus funding for stormwater retrofits over the next several years.

This example appears in Chapter 5 of the Watershed Plans Guidebook. 

Eelgrass and salt marsh restoration in Shinnecock Bay

Cornell Cooperative Extension (CCE) is conducting an assessment of eelgrass in Shinnecock Bay. The goal of this project is to restore coastal ecosystems by restoring eelgrass and scallops, which naturally coexist in this area. The project consists of analyzing aerial photography to identify eelgrass meadows, and then ground truthing those aerial photographs. Going out into the bay, CCE assesses the populations of scallops and eelgrass by looking at stem density, macro algae, bottom types, depth and nutrients. This assessment will help prioritize restoration projects within the bay.

The Cornell Cooperative Extension previously participated in a salt marsh assessment project during the 1990s along the Southampton coastline. Working with a local consultant, degraded town-owned salt marshes were identified and prioritized for potential restoration projects. One successful project restored a former dredge spoil site to a productive salt marsh. The site now offers public access, provides fish and wildlife habitat, and includes a trail and gazebo heavily used by bird watchers.

More information about eelgrass restoration is available through Cornell Cooperative Extension's Eelgrass Program, go here.

This example appears in Chapter 4 of the Watershed Plans Guidebook.