Bioengineering Restoration Strategies for Flashy Semi-Urban Streams: Herrick Hollow Creek, New York

摘要

Amphenol Corporation was required to develop design measures to restore nearly a mile of Herrick Hollow Creek at the Richardson Hill Road Landfill Superfund Site, located in Masonville, NY. Herrick Hollow Creek eventually discharges via Trout Creek to the West Branch of the Delaware River and the Cannonsville Reservoir operated by the New York City Department of Environmental Protection (NYCDEP). New York City water supply undergoes only limited treatment. NYDEP's intense watershed protection requirements are aimed at urging developers and stream restorers to protect the natural purity of their water supply. Previous stream restoration measures designed by others had failed multiple times and much of the fill material placed in the stream corridor had been washed downstream into the drinking water reservoir. The situation was very tense due to the need for the NYCDEP to comply with EPA regulations limiting turbidity in the reservoir, and the NY Attorney General's office was involved. As a result, the Bioengineering Group was contacted to help provide immediate input regarding erosion control and eventually a full restoration design and construction strategy. As an immediate short-term remedy, several field-engineered interim measures were designed and installed to temporarily stabilize the channel. Next, a meeting of stakeholders was convened to establish clear and measurable goals and objectives for the restoration effort. A key to achieving consensus was for all to understand the trade-offs involved and to establish specific and quantifiable ecological restoration priorities. Emphasis on a holistic stream restoration continued by basing the design on site-specific hydrologic data combined of data referencing geomorphically and ecologically appropriate nearby stream reaches. After ecological performance was linked to fundamental geomorphology, full geotechnical and hydraulic engineering analysis was conducted to validate and refine the treatment designs. In early 2007, Bioengineering Group provided a Basis of Design report, with full consideration of the needs of the stakeholders. Stakeholder meetings were convened to establish clear and measurable goals and objectives for the restoration effort, and to gamer local and agency support for the project. We believe that a key to achieving successful consensus on this project was due to the effort to facilitate an understanding of the trade-offs involved in stream restoration projects. The combination of establishing a level of stakeholder communication and understanding, and applying engineering rigor to the project, served to maintain constructive interaction leading to successful project completion.