Bronx River Restoration Projects
Objectives and Constraints
In the Bronx River watershed soils, topography, drainage patterns, and vegetation communities have been so extremely altered that most of the characteristics of healthy riparian and wetland systems can never be completely restored. A more realistic objective is to maximize the sites within the watershed where natural hydrologic patterns (such as infiltration and detention of stormwater) can be restored and where native vegetation can be established. Restoration goals and objectives in the Bronx include:
- Increase native vegetation and porous soils to intercept and infiltrate stormwater, slow runoff and reduce erosion.
- Improve water quality by eliminating direct and indirect pollution inputs, including stormwater from combined sewer outfalls.
- Increase plant diversity through targeted removal of invasive vegetation and planting of a diverse native vegetation.
- Enforce implementation of erosion and sediment control practices.
- Increase community education and stewardship.
- Implement watershed wide plans, in cooperation with Westchester County, to implement goals above.
Freshwater Wetlands and Aquatic Habitat
- Increase native woody vegetation on stream banks to reduce erosion, increase aquatic and canopy cover, improve habitat diversity, slow flow and trap sediment, and create a future source for large woody debris (LWD) recruitment.
- Remove fill from and rehabilitate wetland sites
- Increase in-stream cover by maintaining large woody debris in the channel and adding in-stream structures as appropriate
- Create passages for diadromous fish and increase connectivity between reaches.
- Improve riparian management practices; repair gullies, leave wide un-mowed strips of vegetation along the river, minimize pesticide use, reduce removal of standing dead trees in adjacent areas.
- Control invasive exotic species seed sources and regeneration by using targeted, well-researched, coordinated, and seasonally appropriate management techniques.
- Plant native vegetation.
- Restore tidal marsh through artificial fill removal and re-planting.
- Install inter- and sub-tidal habitat for shellfish and other organisms.
- Eliminate sources of pollution and remove existing garbage and rubble.
Though often small in size, restoration projects work to meet the environmental and social goals listed above. Wetland related restoration projects are shown below, both geographically on the interactive map (click on areas around Woodlawn Tributary, Bronx River Forest, Drew Gardens, Concrete Plant, Lafayette, and Soundview to see NRG restoration efforts) and by topic (below map). Green areas represent wetlands in the Bronx River Watershed. Efforts to restore the relationship between rainfall and soil in the watershed using stormwater best management practices (or low impact development) are also increasing and will ultimately benefit wetlands if implemented on a broad scale
Restoration projects by topic:
- Native Species Plantings
Invasive Species Removal
- Download the Bronx River Riparian Invasive Plant Management Plan
- Bank Stabilization
- Aquatic Habitat Creation
- Pilot Oyster Reef Project
Fish Passage Needs and Feasibility Assessment (2004)
- Anadromous Fish Reintroduction
Several factors make it very difficult to achieve these ecological objectives. The over-riding obstacle is the built-up urban watershed in which the landscape has been irreversibly altered. Though small and incremental changes can be made to lessen the impact of development, the potential for restoring the ecosystem to its previous character is always limited. In the case of the riverine wetlands of the Bronx River, flashy flows from upstream, high sediment loads, and exotic species will continue to impact the wetlands in the Bronx regardless of any local restoration efforts. In the estuary, the hundreds of thousands of cubic yards of fill dumped on top of the salt marsh will never be removed. On-going impacts to consider when evaluating and planning restoration and protection of wetlands in the Bronx include:
- Hydrology, sediment transport, and water quality are largely controlled by activities upstream in Westchester County and cannot be un-done locally.
- High-density urban development and a highly engineered stormwater capture system that prevent infiltration and natural groundwater recharge has disrupted the natural hydrologic cycle that supports wetlands.
- Limited open space in the Bronx reduces the area available for restoration work and forces efforts to be concentrated along the river corridor or small, fragmented sites elsewhere in the watershed.
- Disturbed and contaminated soils that mean exotic species invasion is likely, export of dirty and import of clean soil may be necessary, or human access to the site may be restricted.