Improve Fish Passage Through Culverts

Salmon, trout and other fish and aquatic species are often blocked from their habitat by poorly designed or constructed culverts.  Repairing or removing culverts is costly and requires considerable time and resources.  We have developed a culvert baffle weir that improves fish passage in an effective and economic manner. 

The Flexi-Baffle has been used to improve habitat connectivity for a variety of strong and weak swimming species in hundreds of installations all over the world.  ​  

The current plight of the Killer Whales, or Orca, is partially due to lack of salmon to eat.  Culverts block thousands of miles of productive salmon spawning habitat.  There is a lot of work being done to repair the largest fish passage obstructions.  However, thousands of culverts still block salmon from available spawning habitat. 

The Flexi-Baffle can be used quickly and economically improve culvert passage efficiency to help increase salmon populations that are the key to saving the Killer Whales. 

Flexi-Baffle Installation Mill Brook, VT

The Flexi-Baffle is an Important Tool in Killer Whale Conservation

Culvert with flexible baffles installed to help salmon and eel passage
Culvert before Flexi Baffle installed by County Road Department and Department of Transportation.
Flexible culvert baffle to help salmon, trout and eel pass through culverts

Installing Fish Weirs in a Culvert to Improve Fish Passage

Flexible culvert baffle to help eels pass through culverts Can be installed by Department of Transportation or County Road Departments.

S. Scott & Associates LLC

4719 NE Salmon Creek St

Vancouver, WA 98686

Tel: 1 (360) 601-2391


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S. Scott & Associates LLC

Before and After Fish Weir Installation

Flexi Baffles can be installed by Watershed Councils, Department of Transportation or County Public Works staff.
Flexible culvert baffle to help salmon and trout pass through a box culvert

Fish Passing Culvert After Fish Weir Installation

Flexi Baffle installed to help fish pass through culverts. Can be installed by Watershed Councils, Public Works Departments or Department of Transportation

Prior to Fish Weir Installation

Videos and Pictures


Culvert Fish Weir Flow Study

S. Scott & Associates LLC

Johnson Creek Fish Passage Restoration

Portland, OR

The White River Partnership installed Flexi-Baffles in a culvert on Mill Brook to improve fish passage for brook trout. The Flexi Baffle improved fish passage while maintaining the hydraulic capacity of the culvert.

The Benefits of the Flexi-Baffle 

Installing weirs or baffles is often an option to mitigate poor passage conditions in culverts.  However, a solid weir or baffle often adversely affects the hydraulic capacity of the culvert.  Solid structures can also be damaged during high flow events.  We have developed a flexible weir that can be adapted to a wide variety of culverts to reconnect fish and other aquatic organisms with their habitat.

The Flexi-Baffle Maintains Hydraulic Capacity of the Culvert

The Flexi-Baffle has a flexible design which allows them to bend over and pass flows during high water events.  After the flood event, the Flexi-Baffle returns to vertical thereby creating resting pools and slowing water velocity which provides improved passage conditions. 

 The Flexi-Baffle Improves Habitat Connectivity

The Flexi-Baffle can improve passage for a variety of weak and strong swimming species.  Populations of resident fish and other aquatic organisms can become isolated by poor culvert passage conditions.  Anadromous species, such as salmon and lamprey can be excluded from spawning grounds.  Juvenile eels are often precluded from freshwater habitat by poor culvert passage conditions.  Reconnecting these habitats are the key to conserving these species. 

The Flexi-Baffle Is Simple to Install

The Flexi-Baffle is installed with simple hand tools.  You don’t need expensive tools or a lot of expertise to install the Flexi-Baffle.  A team of two can improve fish passage in most typical culverts in just a few hours.  The Flexi-Baffle can be installed in a variety of culvert shapes and sizes. 

We Can Assist with your Flexi-Baffle Application

Our Fish Passage experts can assist you with your specific application.  Each culvert is different.  We can help design the type and configuration of Flexi-Baffles that will provide the most benefit for your site.   


Learn more from our Fish Passage Experts>>>