Muscota Marsh

• Create public waterfront access to the New York City (NYC) Parks waterfront through land owned by Columbia University.
• Restore saltwater marsh habitat and mudflats by removing invasive species.
• Enhance biodiversity and increase stormwater infiltration by building a freshwater wetland ecosystem connected to the saltwater marsh and tidal mudflats.
• Create a low-maintenance, user-friendly public park.

• The freshwater wetland filters stormwater before it enters the saltwater marsh and mudflats. This dynamic estuarine ecosystem provides essential habitat for numerous wildlife species and supports a variety of native plants including smooth cordgrass (Sporobolus alterniflorus), salt meadow rush (Juncus gerardii), switchgrass (Panicum virgatum), little bluestem (Schizachyrium scoparium), and seaside goldenrod (Solidago sempervirens).
• Due to the close proximity of the saltwater marsh and freshwater wetland, visitors can view wading birds like the great blue heron and snowy egret, as well as leopard frogs and ribbed mussels.
• The restoration included planting 34 trees representing 6 species within the marsh as well as on the adjoining street: black gum/tupelo (Nyssa sylvatica), Eastern redbud (Cercis canadensis), sawtooth oak (Quercus acutissima), English oak (Quercus robur), pin oak (Quercus palustris), and Northern red oak (Quercus rubra).
• A boardwalk made of domestic douglas fir with a metal guardrail topped with a domestic robinia wood wraps around the wetland edge. This raised platform allows visitors to be immersed in the sounds, smells, and sights of the naturalized riverbank.
• An ADA-compliant pier at the end of the boardwalk has an adjustable-height boat dock that is used by Columbia University and the public.
• Anchored seating is artfully arranged along the concrete promenade and picnic area, creating inviting spaces that range from quiet nooks to social gathering spots. Seating options include benches with and without backs and arms, as well as wheelchair-accessible picnic tables. Additionally, tiered sculptural concrete steps in the grassy area offer versatility as elevated viewing spots, an outdoor classroom, and a natural climbing scape for children.
• Lamp posts along the path provide downlighting to provide light where needed, reducing glare and minimizing light pollution to maintain darker skies for migratory and nocturnal wildlife.
• Signage at the park’s entrance and along the pathways explains the marsh’s purpose and provides guidance for visitors on park rules. Trash receptacles are easily accessible along pathways.
• The light grey color of all paths provides visual continuity. The concrete walkways were designed to transition seamlessly with the preexisting permeable pavers and permeable gravel paths from Columbia’s boathouse.
• The entry from 218^th Street to Inwood Park was widened to include access to the marsh and graded to comply with ADA, improving accessibility. The entrance is across from Inwood Park, making Muscota Marsh a convenient waterfront addition to the forest trails. Boulders and bollards at Inwood Park’s entrance remained as markers for the newly widened entrance that integrated public access to the marsh.
• Bike racks at the entrance encourage visitors to use alternate forms of transportation. Additional rentable city bikes can be found on the street leading to the marsh, enhancing access options.
• The design maintained several existing features, including existing riprap along the water’s edge. The old stone wall along the 218^th Street boundary, which was covered in mosses and climbing vines, was preserved to provide a unique transition from the city’s prewar dwellings to the marsh and docks. In addition to this historic structure, the permeable pavers used in front of the dock were retained. An existing groundsel hedge (Baccharis halimifolia) was kept and transplanted on site.
• Several—but not all—of the existing nonnative or invasive trees (Norway maple, Ailanthus, black locust, mulberry) were removed to make way for native species that would further the goals of stormwater filtration.

The landscape architect partnered with three engineering firms to construct a three-tiered freshwater wetland to provide additional habitat beyond the saltwater marsh and tidal mudflats. Moreover, this freshwater ecosystem would provide for the filtration of stormwater before it enters the saltwater marsh and mudflats. Weirs (cement barriers with drains) to control the flow of water were constructed to form freshwater wetland holding tanks. A drainage system was laid starting uphill from the holding tanks to catch water coming down from the street level. Holding areas were planted with various sedges, rushes, and flowering plants meant to filter stormwater and add water retention capacity and pollinator habitat.

In the saltwater marsh transition zones, big and little bluestem, switchgrass, Indian grass, and seaside goldenrod were planted, while the high and low marsh were planted with salt meadow cordgrass and smooth cordgrass, respectively. The plantings were acclimatized to salinity levels, and the marsh was established using pre-planted coconut coir mattresses, which were rolled out on the substrate so that the soil would not suffocate the roots by retaining too much water as the plantings established themselves. Additional details on the plantings are located in Appendix 1 of the Methods Document.

• During the design phase, the engineering team was concerned about high groundwater tables and the potential for saltwater infiltration into the freshwater ecosystem during a drought due to uplift. To counteract this, they integrated a pump system into the design to lower the water table. When budget constraints precluded the purchase of a dewatering line after construction was underway, the team had to adapt and quickly modify the design. The decision was made to lift the freshwater wetlands by one foot. This created steeper slopes in the wetland terrain and resulted in pools. Luckily, the initial design and construction included a gravel bed that had been intended as a filter but ended up working as a drain for the wetland after the design modification.
• In the present day, 10 years after project completion, there has been flooding with high tides and waves caused by large ships coming to dock. Additional soil has been added to embankments to keep saltwater out of the freshwater wetland. If the freshwater wetland had not been raised to begin with, there would have been substantial infiltration of salt water as sea levels rise and high tides increase in the coming years.
• The invasion of phragmites into the native salt meadow cordgrass (Spartina patens), a common issue, has caused maintenance challenges. Since the primary way to restrict phragmites’ growth would be to shade them out, the maintenance plan is focused on management rather than removal, as sunlight is necessary for the herbaceous wetland ecosystem.
• The freshwater wetland was designed to be maintained with regular intervals of de-sedimentation and weir plugging, but due to some miscommunication, this had not been done between 2014-2021. This resulted in sedimentation and nutrient deposits that made invasive species more dominant. However, despite invasive species, native plant communities had formed and were a direct result of the environment that had been created. Thus, to minimize disturbance, it was decided to leave the weirs unplugged permanently.

Furnishings: Landscape Forms, black locust

Project Team

Prime, Landscape Architect, Public Realm: Field Operations
Hydrology, Natural Resources Engineering, and Habitat Restoration: eDesign Dynamics
Civil and Environmental Engineering: Langan Engineering & Environmental Services
Structural Engineering: Halcrow Yolles
Lighting Design: Brandston Partnership Inc

Role of the Landscape Architect

The landscape architect served as the design lead, collaborating with engineers and ecologists through planning, design, and documentation. They directed community outreach and stakeholder engagement and facilitated communication between Columbia University and the New York City Parks Department in balancing community and university needs with the ecological restoration and associated maintenance requirements. Additionally, they guided the design review and permitting processes for the project.