Jamaica Bay, Queens County, NY
In order to evaluate the effectiveness of the state's tidal wetlands program in protecting wetlands under the Tidal Wetlands Act (Article 25 of the Environmental Conservation Law), tidal wetlands trends analyses have been conducted by DEC. These analyses use color infrared aerial photography and geographic information system (GIS) technology. GIS technology allows geographic data, such as aerial photography, to be digitized. Through the use of GIS, a tidal wetlands line can be drawn on a scanned aerial photograph. This information is then checked in the field by marine biologists.
To date, the tidal wetlands trends analysis has shown that the regulatory program to protect tidal wetlands from the historic "fill and build" damage is extremely successful. In many areas, such as Shinnecock and Moriches Bay on Long Island, there is no detectable loss due to those activities. In fact, the wetlands have increased over 250 acres in Shinnecock and Moriches Bay due to the landward migration of the wetlands.
DEC has observed, though, significant losses of vegetated tidal wetlands, principally Spartina alterniflora (Intertidal Marsh), in marsh islands of Jamaica Bay. Examination of historic maps reveals that between 1857 and 1924, the intertidal marsh islands area varied in size without trend, with average changes of up to 10 acres per year. During periods of significant storms, there were losses of marsh islands. But during quiescent years, the marsh islands were able to rebuild. This information was obtained by scanning into a computer tidal wetland boundaries on historic US Coast and Geodetic Survey Maps and aerial photography.
From 1924 to 1974, 780 acres of marsh islands were lost due to direct dredging and filling (which were unregulated activities up to 1974) and 510 acres were lost (approximately 10 acres per year) due to other reasons. This information was obtained through analysis of aerial photography. Since 1974, the study shows that the rate of loss of intertidal marsh islands is accelerating. Between 1974 and 1994, 526 acres of marsh islands were lost at an average rate of 26 acres per year. Between 1994 and 1999, 220 acres were lost at an average rate of 44 acres per year. The vegetated intertidal marsh is being converted to nonvegetated underwater lands. Photographs illustrating this conversion are shown below.
These photographs show the twenty acres of tidal marshes lost between 1974 and 1999 on Black Wall Marsh in Jamaica Bay.
The data indicates significant loss of intertidal marsh (especially islands and also along the shoreline) is occurring in Jamaica Bay, but the reasons are subject to further research. Potential contributing factors include sediment budget disruption, sea level rise, dredging, wave energy, erosion, inlet stabilization, mussel dams on the marshes, and eutrophication. Staff have observed in many areas, that the interior portions of the marsh appear to be at a lower elevation and water logged, soft and compressed rather than "spongy" like healthy marshes.
Sixty-five acres of tidal wetlands were lost on Duck Point Marsh in Jamaica Bay between 1974 and 1999.
In addition, preliminary information suggests that the disappearance of intertidal marshes, at a lesser degree and rate, is occurring in other areas of the marine district (western and eastern portions of Long Island Sound and South Oyster Bay). This discovery makes it prudent to develop an overall strategy for addressing this important natural resource management issue and for communicating findings and implications. Because intertidal marsh is critical to estuarine productivity and New York State has lost much intertidal marsh historically, it is essential to give priority attention to the assessment of the problem marine-district-wide, and develop remediation/restoration/research and monitoring strategies where possible and necessary.
Fifteen acres of tidal wetlands were lost on a section of East High Marsh in Jamaica Bay between 1974 and 1999.
Initial efforts, though, should focus on Jamaica Bay. This is where the most dramatic losses in intertidal marshes, especially islands, in the marine district are known to be occurring. Jamaica Bay is also a regionally important fish, wildlife and plant habitat complex. At least 326 species of birds have been sighted on the wetland islands in Jamaica Bay, including confirmed breeding by 62 species. It is one of the most important migratory shorebird stopover sites in the New York Bight region. Eighty-one species of fish are known to use Jamaica Bay.
On Elders Point Marsh in Jamaica Bay seventy-six acres of tidal wetlands were lost bewteen 1974 and 1999.
Strategies for Addressing Marsh Loss in Jamaica Bay
The following is an outline of strategies for addressing the loss of tidal wetlands in Jamaica Bay. More general strategies have been developed and are available online.
DEC will commit to undertaking the following activities:
- Brief stakeholders (e.g., US National Park Service, US Army Corps of Engineers, NY-NJ Harbor Estuary Program committees, local community groups, elected officials, etc.) on the Jamaica Bay findings by May, 2001 for majority of stakeholders and on-going for others.
- Expand awareness through presentations at technical conferences, workshops and meetings.
- Expand awareness through the DEC website.
- Within the Gateway National Recreational Area lands (where the significant loss of wetlands has occurred), provide assistance and become a partner with the National Parks Service to carry out the following:
- promote interest and awareness of the issues in the research community, and seek support for research to ascertain causes.
- support federal efforts and initiate state efforts to remediate identified causes, targeted in areas proposed for pilot-scale restoration projects.
- make state funds available to initiate pilot-scale restoration efforts in partnership with the landowner (National Park Service).
- assist in pre- and post- restoration monitoring.
- provide information and assistance to the National Park Service Blue Ribbon Panel on Jamaica Bay.
- Within perimeter tidal wetlands (i.e., non-federal property)
- complete wetland trend analysis, particularly to identify areas of significant loss (by August, 2001), then
- work with established partners (e.g., Harbor Estuary Program Habitat Work Group, Jamaica Bay Taskforce) and appropriate landowners, employ funding, and initiate pilot scale demonstration projects.
- For local Jamaica Bay dredge/fill project sites which require DEC permit decisions or mitigation requirements, seek assistance from the regulated community to ascertain the cause and resolution of the marsh loss. These applicants will be briefed on the trend analysis upon permit application submittal and be requested to participate in short and long term restoration efforts, however appropriate.
- Draft an article for the Conservationist.