Lawrence Brook Fish Passage Feasibility Assessment

After obtaining funding from the New England Interstate Water Pollution Control Commission (NEIWPCC), the Lawrence Brook Watershed Partnership contracted Princeton Hydro to provide a preliminary assessment for the feasibility of a fishway to help diadromous fish pass beyond the two dams actively serving the City of New Brunswick Water Utility.  The project is part of the larger Hudson-Raritan Estuary Comprehensive Restoration Plan.

Princeton Hydro completed site investigation, installed pressure-transducers upstream and downstream of the dams, and gathered daily streamflow records to build a robust hydrologic dataset. Incorporating water withdrawal rates provided by the New Brunswick Water Utility, Princeton Hydro then completed a detailed hydrologic and hydraulic analysis that demonstrated project feasibility.

Navigating a complex interaction of multiple factors, Princeton Hydro consulted state fisheries experts and historic records to confirm the target diadromous fish species and reviewed scientific literature to determine their range of swimming abilities, requisite hydraulic conditions, and migration periods. With this information, a conceptual fish ladder design was developed to ascertain the minimum flow requirements to create passable hydraulic conditions within the swimming abilities of the target species. By analyzing daily stream flow records that reflect water withdrawals, Princeton Hydro was able to determine that water withdrawal operations during the fish migration period could be modified slightly to meet both competing needs of water supply and fish passage.