Hydraulic modeling at selected dam-removal and culvert-retrofit sites in the northeastern United States

First posted July 8, 2021 For additional information, contact: Director, New England Water Science CenterU.S. Geological Survey10 Bearfoot RoadNorthborough, MA 01532 Aquatic connectivity projects, such as removing dams and modifying culverts, have substantial benefits. The restoration of natural flow conditions improves water quality, sediment transport, aquatic riparian habitat, fish passage. These projects can also decrease hazards faced by communities lowering water-surface elevations flood waters the risk dam breaches associated with aging or inadequate infrastructure.This report documents provides results one- two-dimensional hydraulic models developed for selected rivers streams in northeastern United States where a was removed culvert retrofitted. were before after removal modification. discharges applied included monthly annual exceedance probabilities 50, 20, 10, 4, 2, 1, 0.5, 0.2 percent.This study, U.S. Survey cooperation Fish Wildlife Service, demonstrates benefits resulting from retrofitting undersized culverts terms decreased during flooding improved Army Corps Engineers Hydrologic Engineering Center’s River Analysis System used to model sites hydraulics, decreases 1-percent probability discharge elevation found at all studied. which impoundment ranged 1.3 10.4 feet. One site, Bradford Dam Westerly, Rhode Island, had only 0.2-foot decrease, but that site replaced series weirs retain upstream allow passage.Minimal differences between computed models. models, however, provide benefit detailed velocity depth data throughout channel resolution not possible one-dimensional model. allowed assessment suitability passage sites. culvert. Prolonged swim criteria species maintained three nine study sites, burst met