Beaver Dam Creek: A Case Study in Watershed Planning

Introduction

The development of a watershed-based restoration plan for Beaver Dam Creek began in January 2001 when the Long Island Wetland Restoration Initiative first convened with the intent to improve communication and cooperation within the regional wetland restoration community. Through follow-up meetings and the work of several subcommittees, eight ‘formerly-connected’ tidal wetlands within Long Island’s South Shore Estuary Reserve were identified as candidate sites for restoration. Wetlands on the tidal portion of Beaver Dam Creek were among these sites.

A Beaver Dam Creek Tributary Corridor Restoration Task Force comprised of federal, state and local government partners, non governmental organizations and academic institutions was subsequently formed to develop and implement a restoration plan for Beaver Dam Creek. This planning and implementation project, coordinated and facilitated by Ducks Unlimited, is aimed at improving the creek's water quality and aquatic habitats through the construction of storm water abatement projects, the restoration of tidal wetlands, and the use of public education and other best management practices. The project is consistent with implementation actions identified in the South Shore Estuary Reserve comprehensive management plan.

The current project is building upon efforts begun as early as 1990, when a report by the Long Island Regional Planning Board first identified the protection and restoration needs of Beaver Dam Creek. A 1996 Town of Brookhaven storm water inventory for South Shore Bays identified and assessed numerous storm water discharge points into the creek, and was the basis for a Bellhaven Road watershed management plan prepared for Brookhaven by the Suffolk County Soil and Water Conservation District. This watershed plan is the basis for storm water remediation work currently being done in the Bellhaven community by Brookhaven with support from New York Clean Water / Clean Air Bond Act funds.

The Post-Morrow Foundation also has had a long interest in the protection and restoration of Beaver Dam Creek. In 1999, the Foundation, along with the U.S. Fish and Wildlife Service and Cornell Cooperative Extension, restored a small section of tidal wetlands at the end of Clover Lane. The Foundation purchased and protected a forty-nine-acre farm on the west side of the creek in 2000, and has purchased several smaller parcels along the creek as well. Additionally, the Foundation is pursuing purchase of a nine-acre parcel at the headwaters of Beaver Dam Creek and is developing a best management practices plan for a small marina it owns on the west side of the creek.

Background

Beaver Dam Creek is a semi-rural tributary of Great South Bay. The creek's 2,096 acre / 3.3 square mile watershed lies entirely within the Town of Brookhaven in Suffolk County (7.5' Quadrangle: Bellport, NY). The 1.1 mile tidal portion of the creek, up to the Beaver Dam Road bridge, is a designated Significant Coastal Fish and Wildlife Habitat due to the rarity in the region of such relatively undeveloped tidal channels bordered by substantial tidal marshlands. Beaver Dam Creek is also one of only five streams on Long Island with significant concentrations of sea-run brown trout and supports an autumn recreational fishery of county-level significance.

Use impairments in Beaver Dam Creek are identified in the 2000 Atlantic Ocean/Long Island Sound Basin Waterbody Inventory and Priority Waterbodies List (PWL). According to the PWL, year-round shell fishing restrictions apply in the tidal portion of the creek due to the potential for pathogen introduction from marine toilets, and urban and storm water runoff. Other recreational uses of the creek are considered stressed based on these shell fishing restrictions.

Beaver Dam Creek forms the western edge of the Carmans River flood plain and was once flanked by expansive salt marshes. Dredging in the 1920's and again in the 1960's resulted in the construction of dikes along the creek and the placement of dredge spoil on the marshes along both shores. Consequently, numerous benefits provided by wetlands were lost, including a significant amount of wildlife habitats, natural filtration of overland runoff, buffering against storm surges, and nursery functions for various estuarine species. Accompanying development within the watershed was storm water runoff and other nonpoint source pollution, and significant alterations to wetland hydrology from grid ditching for mosquito control. The invasive common reed (Phragmites australis) also became widespread.

As part of a general characterization of the watershed, the Suffolk County Planning Department (SCPD) is in the process of preparing tax map scale geographic information system (GIS) maps of the Beaver Dam Creek watershed detailing the existing land use and ownership of all recreation and open space parcels. In addition to the field verified GIS maps, the SCPD will tabulate land use acreage within the Beaver Dam Creek watershed for the thirteen land use categories that are commonly used for regional planning purposes.

Water Quality

A watershed analysis of Beaver Dam Creek completed in January of 2002 identified 12 locations where storm water runoff discharges into the creek. Three discharge points are of immediate concern:

· the Bellhaven community on the southwest side of the creek;
· the farm on the northwest side of the creek; and
· the north side of the railroad tracks (representing concentrated flow from Montauk Highway).

The Suffolk County Soil and Water Conservation District (SWCD) is assisting the Town of Brookhaven with redesigning the storm water management system at key discharge points bordering the creek in the Bellhaven community. The Town of Brookhaven has received a New York Clean Water / Clean Air Bond Act grant for $88,230 to apply toward completion of the project, which is scheduled to begin spring 2003.

The USDA Natural Resources Conservation Service has helped develop a comprehensive conservation plan, as per Agricultural Environmental Management (AEM) planning guidelines, for the 33-acre vegetable farm bordering Beaver Dam Creek that grows lettuce, spinach and cabbage. The plan identifies conservation practices necessary to improve soil quality, reduce and filter runoff, and protect groundwater.

Site Design and Monitoring

Site design and monitoring for the Beaver Dam Creek restoration project have been coordinated to date by Ducks Unlimited (DU) and the US Fish and Wildlife Service (USFWS), with input from numerous other partners. Current restoration efforts focus on an eight-acre parcel owned by the Post-Morrow Foundation on the east side of the creek.

Site Design and Habitat Restoration

Efforts to create a site design for the proposed restoration project involved numerous visits to the project location by DU, USFWS, regulatory personnel from the NYS Department of Environmental Conservation (NYSDEC), and several other partner agencies. Existing conditions on the site were surveyed to provide a base map on which to delineate the final project design. An accurate survey of the current elevation profile is critical for determining the amount of material, i.e., dredge spoil, to be removed from the site; elevations of areas of healthy, functioning marsh serve as benchmarks for final grades. An overlay of the final design on the base map allows for the proposed acreage of restored mud flat, low marsh, and high marsh to be calculated. These figures are then used to determine the amount of plant material needed to revegetate the site once final grading is achieved. The proposed site design is required as part of the permit package by the Town of Brookhaven, submitted to the NYSDEC, the US Army Corps of Engineers, and to the NYS Department of State for consistency review.

Ducks Unlimited is coordinating habitat restoration work. The first phase of the project, anticipated for completion in summer 2003, will remove most of the dredge spoil on the east side of the creek. The second phase of the project, anticipated for winter 2004, will involve partial removal of the dike along the east side of the creek, control of common reed, removal of the remaining dredge spoil, and final grading of the site. This work will be followed with planting of native salt marsh grasses and shrubs in May-June 2004. These restoration efforts are being supported through: a $40,000 Community-based Restoration Program grant from the National Oceanic and Atmospheric Administration; a $9,000 contribution from the Post-Morrow Foundation; two Clean Water / Clean Air Bond Act grants to the Town of Brookhaven, totalling $220,000, and an equal amount of Town matching funds; a $10,000 award from the US Fish and Wildlife Service Partners for Fish and Wildlife; and in-kind services contributed by Ducks Unlimited, the US Fish and Wildlife Service, and the Town of Brookhaven.

Natural hydrology patterns resulting from this restoration will provide increased habitat for the numerous wildlife species dependent upon salt marshes. Waterfowl, shorebirds and long-legged wading birds will benefit from the mud flats, open water, and intertidal marsh that will be created. Resident finfish such as common mummichog, striped killifish and sheepshead minnow, and seasonal visitors such as Atlantic silverside, bay anchovy, Atlantic menhaden, winter flounder, bluefish, striped bass, and fluke, will benefit from increased foraging, breeding, and nursery habitat. Expected increases in marsh fish will provide important foraging opportunities for blue crabs, terns, egrets and herons.

Monitoring

Monitoring of physical and biological characteristics at the proposed restoration site was begun in fall 2001. Parameters were chosen to allow an objective assessment of pre- and post-restoration conditions. These parameters include height of the water table, soil salinity, and plant species composition. Visual documentation of the site will be captured through photo monitoring from fixed-point locations.

Measurements of the water table and soil salinity will be taken monthly during the growing season, and vegetation data collection and photo monitoring will be completed annually at the end of summer. After completion of the project, anticipated for spring 2004, post-restoration monitoring will continue for five years.

Monitoring efforts will follow protocols established in a regional study of open marsh water management (OMWM) by the US Geological Survey and US Fish and Wildlife Service. With limited resources always an issue, the monitoring plan for this project allows for the collection of relevant physical and biological characteristics with reasonable time and financial commitments by the partner agencies. Photo monitoring, in particular, is a low-cost method for evaluating the structural attributes of the site from year to year.

With a $60,000 Community-based Restoration Program grant from the National Oceanic and Atmospheric Administration, DU is working with Southampton College and Cornell Cooperative Extension to monitor the fish community at the restoration site. Both pre- and post-restoration sampling will be conducted to evaluate the impacts of the restoration efforts on finfish that are dependent on salt marshes for their life cycle.

Water quality monitoring is being conducted by the Suffolk County Health Department Office of Ecology on a voluntary basis. Samples are collected monthly at four marine and four freshwater sites. Routine sampling parameters will include ammonia, nitrite + nitrate, urea, total nitrogen, dissolved inorganic phosphate, total phosphorus, silicates, total and fecal coliform bacteria, metals and volatile organic compounds (VOC’s). Sampling for pesticides will be conducted on a quarterly basis. These data will be invaluable in identifying where mitigation measures should be concentrated within the watershed.

Education and Outreach

Critical to the project is an education and outreach subcommittee comprised of New York Sea Grant, Cornell Cooperative Extension of Suffolk County, Ducks Unlimited, the US Department of Agriculture’s Natural Resources Conservation Service, the Suffolk County Soil and Water Conservation District, and the Post-Morrow Foundation. The group has focused on documenting and promoting the progress of the restoration effort, developing educational materials on preventive and restorative measures to protect the creek, and identifying undeveloped land in the watershed that could be protected.

Accomplishments of the subcommittee include:

· two newsletters of the Post-Morrow Foundation (spring 1999, winter 2002) that explain the scope of the project and progress to date, distributed to more than 3,000 residents of the area;
· an article on the project in Sea Grant’s magazine Coastlines (Vol 31/No2);
· a brochure titled Beaver Dam Creek Restoration Project, which provides background on the project;
· a second brochure titled Help Protect Beaver Dam Creek, which explains the impacts of storm water runoff on the creek and how homeowners can help reduce those impacts;
· a Powerpoint presentation on the project, presented by Ducks Unlimited staff at the spring 2002 annual meeting of the Brookhaven Village Association; and
· an article on Lohmann’s Farm and its stewardship of the farmland along Beaver Dam Creek, highlighted in the NYS Soil and Water Conservation Committee Agricultural Environmental Management 2002 Annual Report.

In addition to these efforts, Cornell Cooperative Extension of Suffolk County has begun development of a video of the entire planning and restoration process. The video will be used for education and outreach within the Beaver Dam Creek watershed and made available to other communities interested in embarking on such watershed-based resource management.

The subcommittee has held discussions with the Bellport High School Science Department in an effort to develop projects that include high school students. One project identified is a summer science program that focuses on the impacts of lawn care products on the creek’s water quality and what homeowners can do to reduce those impacts.

The subcommittee plans to continue its education and outreach activities in an effort to create a strong investment in the restoration project on the part of all residents within the watershed, and in particular among those landowners whose properties are adjacent to and developed down to the creek. Having local residents become active stewards of the watershed is key to ensuring the long-term health of Beaver Dam Creek.