Abstract: Session A  9:30 am (BACK)
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A Post-Disaster Culvert Replacement and Stream Restoration Project for Aquatic Organism Passage in New York

Kevin Verweire
HDR
Walton, New York

Flooding from Hurricane Irene and Tropical Storm Lee impacted streams in New York during August and September of 2011, and a Federal Emergency Management Agency (FEMA) disaster declaration was subsequently issued. The Town of Warwick, Orange County, New York experienced damage to multiple culverts and infrastructure as a result of the storms. One such structure, the Brady Road culvert, was a six-foot diameter circular pipe that drained 0.9 square miles of the predominantly forested Cascade Brook watershed. Cascade Brook is a second order perennial trout stream, with a Rosgen classification of C4b, which drains to the Village of Warwick drinking water supply reservoir.  Severe damage to the culvert as a result of the storms included partial road collapse, damage to the structural integrity of the culvert, and erosion of culvert backfill and sub-base. Downstream scour resulted in a perched culvert condition of approximately six feet above the new downstream base level that prevented passage for brook trout (Salvelinus fontinalis).

Following the storm events, in 2012 FEMA awarded funding to replace the culvert in-kind with no hazard mitigation. With a desire to have a more resilient road crossing, and following recommendations from the New York State Department of Environmental Conservation to establish conditions for fish passage, the Town of Warwick subsequently filed an appeal to FEMA to include funding for replacement of the damaged culvert with a three-sided box culvert, including natural streambed and downstream restoration. Ultimately in 2015 FEMA agreed to the Town’s appeal which led to a design to support aquatic organism passage upstream and downstream of the culvert location.

The culvert and stream restoration design was accomplished using a combination of Rosgen Natural Channel Design and U.S. Forest Service (USFS) Stream Simulation techniques. Culvert passage for the design species, brook trout, was modeled using the USFS FishXing software. Downstream of the new culvert a series of rock step-pools and grade control structures were established to allow fish passage, and to restore a Rosgen B4a channel for approximately 500 feet. The project was constructed during the fall of 2016, five years after the initial storm impact.