Verdantas is leading the design of a nature-like fishway at Grand Falls Dam on the St. Croix (Skutik) River along the Maine-New Brunswick border. The proposed bypass will provide upstream passage for migratory fish and, together with passage improvements at downstream dams, help reconnect fish with extensive habitat throughout the St. Croix watershed. The river holds the largest potential habitat for migratory river herring on the East Coast, with the capacity to support an estimated 20–60 million fish.
At approximately 4,000 feet long with a 50-foot elevation gain, the proposed bypass is expected to be one of the longest nature-like fishways of its kind. The design creates a low-gradient channel that emulates natural stream conditions, using sloping novel rock vanes and boulders to dissipate energy, create varied flow conditions, and provide resting areas for migrating fish.
Given the scale and hydraulic complexity of the proposed fishway, Verdantas is using computational fluid dynamics (CFD) modeling as an integral part of the design process. CFD allows the team to evaluate complex flow conditions throughout the nature-like channel, refine the hydraulic design, and reduce uncertainty in how the proposed fishway will perform. This model-informed approach provides greater flexibility as the design advances while helping create hydraulic conditions conducive to successful fish passage.
Verdantas' multidisciplinary scope also includes hydrologic data analysis, bathymetric and topographic surveys, geotechnical exploration and engineering, structural and civil engineering, permitting, cost estimating, and coordination with state, federal, Canadian, Tribal, and other project stakeholders.
Project Highlights:
- Approximately 4,000-foot-long nature-like fishway with a 50-foot elevation gain
- CFD modeling to refine hydraulic conditions and reduce design uncertainty
- Nature-like channel design incorporating novel rock vanes, boulders, variable flow conditions, and resting areas
- Hydrologic and hydraulic analysis and design
- Bathymetric, topographic, and geotechnical investigations
- Multidisciplinary engineering, permitting, and stakeholder coordination
