Saw Mill Creek, on the west shore of Staten Island, was threatened by factors such as illegal dumping and invasive weeds for years. During Superstorm Sandy in 2012, the creek suffered from severe flooding, which only worsened the degradation. A strategy was developed to protect the 54-acre Saw Mill Creek wetlands, while fostering sustainable waterfront development. These wetlands are located in an area with a mix of industrial land adjacent to salt marsh and coastal forests.
WSP was chosen by the NYC Economic Development Corporation, in collaboration with other city, state and federal agencies, to provide permitting and wetland restoration design for the Saw Mill Creek Marsh project, the city's first wetland mitigation bank. This pilot project, part of the Mitigation and Restoration Strategies for Habitat and Ecological Sustainability Initiative, sought to:
- Improve water and sediment quality.
- Increase plant and wildlife diversity.
- Improve storm surge protection on the west shore of Staten Island and enhance its capacity to handle flooding.
WSP developed an ecological assessment methodology and conducted surveying and environmental testing, including sediment sampling and wetland functional assessments. A vegetation analysis and a threatened/endangered species analysis were also performed. WSP then provided a feasibility study, construction cost estimates, a construction schedule, and restoration design plans for emergent wetlands, scrub-shrub wetlands, freshwater forested wetlands, open water channels/pools, mudflat habitat, and uplands.
Rewilding Success
Now in the fourth year of post-construction maintenance and monitoring, the Saw Mill Creek Bank is a thriving habitat that successfully supports a variety of plants and wildlife, and provide a living solution to storm surge resilience and flood protection.
Recent monitoring activity observed:
- 33 bird species, including a New York Species of Special Concern, osprey, and a High Priority Species of Greatest Conservation Need, saltmarsh sparrow;
- macrofauna from coffee bean and mud snails, ribbed mussel, and various types of crabs to striped killifish, garter snake, red fox, domestic cats, and white-tailed deer; and
- vegetation monitoring measured approximately 88 percent, dominated by native saltgrass, smooth cordgrass, and saltmeadow cordgrass.
The monitoring was conducted in accordance with the Mitigation Banking Instrument, to establish guidelines and responsibilities for the establishment, use, operation and maintenance of the Saw Mill Creek Marsh.
