St. Croix Fish Passage | Projects

In recent years Verdantas' Flow Labs team (formerly Alden Research Laboratory) has supported the planning, feasibility, and design efforts to restore and improve fish passage on the St. Croix River which boarders Maine and New Brunswick. Our team contributed to the International Joint Commission of the St. Croix River’s evaluation of fish passage improvements for Woodland and Grand Falls Dams. Since the study was published, we have continued to advance fish passage designs working with the State of Maine’s Department of Marine Resources (MDMR), The Nature Conservancy (TNC), and the Passamaquoddy Tribe (Tribe). Improved fish passage on the St. Croix River will open up 600 miles for migratory fish and 60,000 acres of habitat for alewives.

We are currently aiding the Tribe and project partners by conducting field studies to inform the design for upstream and downstream fish passage with funding from NOAA. Studies include American eel surveys using traps and telemetry studies to track the downstream movement of juvenile herring and adult eels. A feasibility study of design alternatives for downstream passage will assess the results of the study to help select an effective alternative.

At Woodland Dam the existing Denil fish ladder is in disrepair and does not meet current Fish and Wildlife design guidelines for the target anadromous species. New fish passage facilities would substantially improve fish passage to crucial habitat. Verdantas, under contract to MDMR, is developing a fish lift, fish ladder downstream passage facilities designs with a scope includes hydraulic modeling of the tailrace and fishway components, geotechnical borings and engineering, water level measurements, permitting, agency and stakeholder consultations, construction cost estimates and completing the final design drawings and bid documents for construction. The primary funders of the project include MDMR, NOAA and FWS.

At the Grand Falls Dam and Powerhouse, under contract to TNC, Verdantas is evaluating and designing upstream fish passage facilities. The existing fish ladder, along with the Woodland existing fish ladder may be the longest and highest head Denil ladders that are known and are in poor condition with visible leaks, cracks, and misaligned offsets at concrete joints. Verdantas is evaluating and advancing designs for a nature-like fishway (NLF) at Grand Falls. The NLF design will emulate a natural stream with a low gradient using sloping rock vanes and boulders to dissipate energy and provide variable flow patterns conducive to fish passage and resting zones. The design process includes using computational fluid dynamic (CFD) modeling as a design tool, to optimize hydraulic conditions for fish passage and reduce design uncertainty. The fish passage design scope includes a bathymetry and topographic surveys, geotechnical exploration pits, borings and engineering, hydraulic modeling, hydrology and hydraulic design, permitting, agency and stakeholder consultations, construction cost estimates and completing the final design drawings and construction bid documents.

The designs at each project are being developed with input and feedback from project stakeholders and agencies including Woodland Pulp, state and federal agencies, Canadian agencies, TNC the Tribe and Peskotomuhkati at Skutik.

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