Aquatic connectivity is a key restoration goal for HEP and its partners. While aquatic connectivity has been studied in Estuary watersheds of New Jersey with respect to dams, the effectiveness of fish passage at many structures, such as culverts and bridges, has not been assessed. Based in part on similar efforts by the Hudson River Estuary Program in New York, HEP is assessing road-stream crossings for how well they are able to pass fish and other aquatic life and any hydraulic capacity issues that may lead to roadway flooding and erosion. We use these assessments to prioritize restoration of the crossing. Increases in rainfall due to climate change makes investing in these improvements a growing priority.
We use the protocols, training methods and collective database developed by the North Atlantic Aquatic Connectivity Collaborative (NAACC). The information collected during the NAACC assessment is then used in a model developed by the Cornell University Water Resources Institute to assess the maximum storm interval (e.g. 100-year storm event) that the bridge/culvert can accommodate without the flow topping the road or causing roadside/streambank erosion. The combination of these two data sets can be utilized by state and local planning and transportation agencies to prioritize and replace undersized bridges/culverts with climate-ready, connectivity-friendly versions.
Thanks to a 2020 EPA Coastal Watershed Grant administered by Restore America's Estuaries, HEP is partnering with the Rutgers Sustainable Raritan River Initiative to scale-up this connectivity project to assess over 300 road/stream crossings in the Lower Raritan and South Rivers in coastal New Jersey. Additional project development partners include: Montclair University, HR Estuary Program, Cornell University, and USACE. Thirteen subwatersheds and more than 320 crossings have already been assessed.
Just Released! Princeton Hydro and HEP have created a toolkit to prioritize problematic road-stream crossings and identify possible solutions at potential project sites. Learn more about it here. Download the toolkit here.
Just Released! Princeton Hydro has created a 30% design for a priority culvert replacement on Iresick Brook in Old Bridge, NJ. See the design report here.