Working to
Restore Rivers
Since 1984

Credit for video clip of kingfisher: MIT Media Lab’s Responsive Environments Group, in collaboration with Living Observatory, at Mass Audubon’s Tidmarsh Wildlife Sanctuary. Used by permission.

Our Work


Dam Removal & Fish Passage

Fish passage barriers across the United States are being removed or modified to help fish and wildlife, improve safety and boost recreation. We’ve worked on 150+ dam removals, removed hundreds of culverts, and developed best practices resources for bridge crossings.


Estuary Restoration

Estuaries are dynamic ecosystems where oceans, rivers and human economies converge; they’re also critical to rearing grounds for fish and wildlife and at particular risk to a changing climate. Across the country, we’re reconnecting and restoring these habitats.



Beginning with the daylighting of Tanner Creek in Portland (1992), we’ve been collaborating with urban planners and landscape architects to restore urban streams from coast to coast in the US and abroad.

Inter-Fluve has completed over 2,400 projects. Here’s where we’ve been working.

Mud gets a bad rap.

Marl, a sedimentary substance rich in calcium carbonate and occasionally interspersed with clay and silt, has a variety of useful qualities. It has long been used in fertilizer all over the world. For trout, it can provide ideal habitat. This chalky mud harmonizes pH levels when it is present in streams, and it can regulate water temperatures via groundwater interaction—perfect conditions for trout.

However, marl can pose challenges for river restoration. It is soft and crumbly, making it vulnerable to bank instability or collapse. Additionally, the disturbance of marl beds can cause a temporary increase in water turbidity, which can harm aquatic life and impede construction visibility. It's crucial to take special care when working in areas with marl deposits to minimize environmental impact and to ensure the safety and efficiency of construction operations.

Colm Tóibín's poetic musing underscores these two characteristics of marl—its accretion over the centuries makes it valuable, but it is also a challenge to work with. #trout #flyfishing #river #geology #geologyrocks #environment #environmentalscience

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It's #nationalestuariesweek again! When working in these delicate and important ecosystems, we take extra care to minimize construction impacts. In this case, it involved using barges to transport equipment. #estuary #pnw #construction #ecology #waterresources #barge #bargelife ...

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NOAA and American Rivers teamed up to remove Bloede Dam on the Patapsco River, restoring vital habitat for migratory species. A recent study shows river herring now using the reopened area. Read the full article here: #DamRemoval #HabitatRestoration #MigratoryFish #Conservation
Image credit: Chesapeake Bay Program

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