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Lower Assunpink Creek Ecosystem Restoration

Project Background

The U.S. Army Corps of Engineers Philadelphia District initiated an environmental restoration project for the lower Assunpink Creek area under authority of Section 1135 of the Water Resources Development Act. As amended, the Act provides authority for modifying the structure or operation of an existing USACE project to improve the quality of the environment in the public interest and for determining if the operation of such a project has contributed to the degradation of the quality of the environment. The City of Trenton, New Jersey, will serve as the non-Federal project sponsor.

The Lower Assunpink Creek Ecosystem Restoration Project study area is located along a 3- mile section of the lower Assunpink Creek in Trenton, New Jersey. Assunpink Creek is 25 miles long, and drains approximately 91 square miles in central New Jersey. The main tributaries that feed Assunpink Creek are Shabakunk Creek and Miry Run. The headwaters begin in Millstone Township, in Monmouth County, and flow into the Delaware River in Trenton. The project area evaluated during the study process encompasses a 500-foot section of the lower Assunpink Creek in downtown Trenton where the creek is contained within a buried box culvert known as the Broad Street culvert.

From the Delaware River to the Trenton city limits, several former industrial sites, abandoned bridges, and the Broad Street culvert were identified as candidates for ecological restoration. The Broad Street culvert experienced a structural failure, which increased the urgency to implement a restoration action that would also address a public safety hazard. The Broad Street culvert is located in the heart of the downtown business district and is on a recovering urban stream that connects various greenway areas and transportation facilities.

The day lighting of the stream occurs through removal of the culvert roof structure, allowing the stream to be exposed to natural sunlight. The resulting open channel design will improve anadromous fish migration, as low-light conditions can disorient migrating fish, hindering their ability to spawn upstream. The project will also benefit businesses adjacent to the site, provide recreational options for visitors and local residents, and provide historical and educational opportunities for the community.

Current Status

The Army Corps of Engineers Philadelphia executed a Project Partnership Agreement with the City of Trenton in September of 2009. The project plans are currently under review. The city of Trenton, the non-Federal sponsor, will contract to analyze utility relocation design alternatives to determine how to best relocate utilities that cross the creek. New Jersey flood hazard area and Freshwater Wetlands General Permit applications are under review. Soil erosion and sediment control plans have been submitted to Mercer County.

Advertisement of the construction contract is scheduled for the end of the 4th quarter of fiscal year 2012 pending the availability of construction funds.

Project Goals

The goal of the Lower Assunpink Creek Ecosystem Restoration Project is to restore migratory fish habitat, enhance recreational opportunities, and improve the overall stream ecology of Assunpink Creek. Project goals will be accomplished through day lighting the Broad Street culvert and creation of an open-channel system. Additionally, restoring the freshwater ecology and creating recreational opportunities for the public will benefit the overall economy of the City of Trenton and the region.