About the Event
Culverts can act as barriers to fish and other aquatic organism movement in streams for a number of reasons, including insufficient water depth, excess velocity, excess turbulence, or insufficient roughness. In addition, fish and other aquatic organisms may encounter a behavioral barrier due to different conditions (such as light) within the culvert. These barriers to movement are detrimental to fish and other aquatic organisms because they may limit migration during key times such as spawning and may isolate endangered populations.
This presentation covered a series of experiments conducted in the field and at St. Anthony Falls Laboratory to examine the physical performance of fish passage culvert design as well as the behavior of warm water species when approaching a dark culvert. While significant research efforts have been made to understand the swimming abilities of individual fish, our projects examine other aspects of fish and aquatic organism passage through culverts: culvert performance in terms of sediment transport into and through embedded culverts, potential behavioral barriers, and novel methods to add roughness along the boundaries of concrete box culverts.
These experiments provide guidance to culvert designers on the need for sediment placement within embedded culverts to maintain natural stream bed roughness, the need for light mitigation strategies in long, dark culverts, and the ability to utilize inexpensive methods to retrofit culverts with additional boundary roughness. These experiments focus on Minnesota culvert design for aquatic organism passage, but lessons learned are applicable to other locations with similar geomorphic characteristics and fish communities.
Jessica Kozarek is a research associate and research manager of the Outdoor StreamLab at the University of Minnesota's St. Anthony Falls Laboratory. Her research interests include fish passage, stream restoration, in-stream nutrient dynamics and habitat, and the ecogeomorphological responses to flood flows in vegetated stream systems.