Sunday, April 12, 2015

Bringing the Assunpink Creek Back Into the Daylight in Trenton

Assunpink Creek flowing through Trenton near Mill Hill Park
Work is expected to begin on a $4 million restoration this spring that is being financed 75 percent by the U.S. Army Corps of Engineers and 25 percent by the DEP through a federal Clean Water Act grant.

What the project hopes to accomplish is to restore the Assunpink Creek in downtown Trenton. You say you've never seen it? That's because decades ago this tributary of the Delaware River was channeled into an underground culvert. It disappears from view between South Broad and South Warren streets.

The idea years ago was certainly to allow for greater development where the creek flowed, but the culvert prevented fish from migrating into the Delaware. The downtown also lost the natural beauty of the stream.

Maybe it was a sign from nature when the nine years ago part of the culvert roof collapsed. The immediate effect was not good - a safety hazard that was fenced off and became an overgrown lot.

But this project to restore the creek looks like it will now happen.

On the New Jersey Future website at, you can see maps and historic photos.

The term for this restoration is "daylighting," as in bringing back the water to the light of day from its capture underground.

The 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 creek gathers intensity as it meanders west from Millstone Township in Monmouth County, through the Assunpink Wildlife Management Area and Mercer County Park, across the old, flat clays and silts of the Raritan and Magothy formations into Trenton.

The Lower Assunpink Creek Ecosystem Restoration Project study area is located on a 3- mile section of the Assunpink Creek between the Delaware River and the Trenton city limits. Several former industrial sites, abandoned bridges, and a 500-foot section of the creek between Broad and Warren Streets, contained within a buried box culvert were identified as candidates for ecological restoration.

The buried box culvert, known locally as the Broad Street culvert, was evaluated during the feasibility study and approved for removal and restoration of a natural creek channel. The Broad Street culvert removal project is located in the heart of the downtown Trenton business and historic district on a recovering urban stream that also serves to connect several greenway and urban park facilities.

illustration via

The project site is also the location of the the Battle of Assunpink Creek (AKA the Second Battle of Trenton) during the American Revolution. On Jan. 2, 1777, the Continental Army and supporting militias held a defensive line along the creek's south shore. Under George Washington's command, the Americans repelled charges by British and Hessian soldiers across a stone bridge spanning the creek, as well as an attempt to ford the creek near its mouth.

By morning, Washington had reached Princeton and after a brief battle, the British there were decisively defeated and most of the garrison was captured. With their third defeat in ten days, Cornwallis' superior, General William Howe ordered the army to withdraw from southern New Jersey and most of the way back to New York. The British left forward positions at New Brunswick and Washington moved his army to Morristown for winter quarters.

The daylighting of the stream this year will mean the removal of the culvert structure, allowing the stream to be exposed to natural sunlight, and the resulting open channel design will improve anadromous fish migration. 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.

The name Assunpink comes from the Lenape word for "stony, watery place," describing the gravelly springs of New Jersey's 65 million-year-old ancient coastline. This ironstone "cuesta," or ridgeline divides the inner and outer coastal plains.

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