Boswell was retained by the County of Passaic to provide engineering design, permitting, surveying and construction management services for the rehabilitation of an existing duck pond and a 2-mile stretch of the Goffle Brook flowing through Goffle Brook Park in Hawthorne, New Jersey.

The banks of Goffle Brook displayed evidence of progressive erosion at numerous locations along the study area.  Additionally, the brook’s flow has eroded the banks and exposed the root system of existing vegetation.  Moreover, an on-stream duck pond was exhibiting degradation and ectophization due to siltation/sedimentation combined with an overabundance of resident waterfowl.

Boswell worked closely with the NJDEP in terms of permitting and bioengineering.  Due to the project’s size and scope the State required a Freshwater Wetland Individual Permit (IP) rather than a common general permit.  Next, Boswell designed bioengineering bank stabilization methods to include:

•   Live Stakings;
•   Vegetated geogrid; and
•   Vegetated gabion baskets.

The NJDEP was particularly interested in the project’s design and planned to use the project as a case study for future bioengineering rehabilitation.

This project will demonstrate the ability to restore a damaged, riparian corridor within the 91-acre Goffle Brook Park by reducing riverbank erosion, flood damages, and non-point source pollution (primarily TMDL, fecal coliform, and polluted runoff).  The methods Boswell will use to restore the damaged stream corridor will include dredging, bioengineering, and vegetated gabion baskets.  The first phase of the project will be the dredging of large sediment deposits (shoals) that have formed in the Goffle Brook.  The shoals can be found near the banks or in the center of the stream channel.  The largest shoals are located in the middle of the stream and are heavily overgrown with wetland vegetation.   These sediment deposits have formed small islands throughout the stream which divide the channel’s flow pattern and prevents proper drainage.

The second phase of the project will be to install vegetated gabion baskets in the most severely eroded areas of the stream corridor.  The gabion baskets will reshape the original banks of the Goffle Brook, while providing a solid base for various types of vegetation.  The baskets will also prevent the formation of future shoals by filtering out any silt and debris carried by surface runoff.

The final phase of the project involves implementing a comprehensive bioengineering plan.  The plan will use native herbaceous plants, shrubs and trees to restore the stream banks and eliminate the resident geese population.  The stream banks will be re-established using a variety of naturally occurring herbaceous ground cover.  The ground cover will prevent erosion near the banks of the stream by creating a complex root system and act as a filtration device by removing chemicals and fecal coliform from groundwater runoff.  The vegetation to be planted along the perimeter of the duck pond will also incorporate native ground cover, however, an additional variety of shrubs and small trees will be used to limit the resident geese population’s access to the pond.

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