Browsing by Subject "Fishes"

Now showing 1 - 3 of 3
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    Assessing Culverts in Minnesota: Fish Passage and Storm Vulnerability
    (Minnesota Department of Transportation, 2021-11) Kozarek, Jessica; Herb, William; Bentelspacher, Nick
    Culverts at road-stream crossings can create barriers to movement within a stream network that can have dramatic consequences for fish populations by fragmenting habitat. Culverts can become barriers when flow conditions exceed fish swimming ability, e.g., for drop at the outlet and insufficient depth or excess flow velocity. In this project, we use a simple modeling framework to assess 50 culverts throughout Minnesota to: a) determine what fraction of these culverts currently present a fish passage barrier for both high flows (velocity barrier) and low flows (depth barrier) and b) to summarize design parameters that most affect passibility (e.g., culvert width). The estimated high and low flows are fed into the HY-8 culvert hydraulics model, and the resulting velocity and depths are compared to published fish swimming capabilities. We also assess future (2061-2080) high- and low-flow fish passage conditions for five culvert sites using global climate model outputs, Hydrologic Simulation Program Fortran (HSPF) runoff models, and the fish passibility modeling framework. Both low- and high-flow conditions in streams are very responsive to future climate, with either positive or negative future changes, depending on which global climate model is used. This study concludes that maintaining a low-flow channel or embedded culvert barrel will make culverts more passable during changes in low flows and ensuring culvert widths equal to or greater than the bankfull channel width in combination with embedded sediment will help mitigate increases in high fish passage flows and high peak flows.
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    Sediment Transport through Recessed Culverts: Laboratory Experiments
    (Minnesota Department of Transportation, 2015-03) Kozarek, Jessica; Mielke, Sara
    Recessed culverts are often installed in Minnesota to facilitate aquatic organism passage (AOP) by providing a natural streambed through the culvert. The least expensive option when installing a recessed culvert is to allow the culvert to fill in with sediment naturally over time; however, previous field studies suggest that in many cases, sediment fails to deposit within the culvert. The objective of this research was to understand the function of a culvert set below the streambed elevation under various sediment transport conditions. Laboratory experiments were designed to assess the performance of recessed culverts across a range of geomorphic characteristics representative of Minnesota streams. These experiments explored the functionality of a culvert that is prefilled with sediment representative of the stream as a part of the installation process against one that is empty after installation and assessed the potential for headcutting and downstream degradation. The experiments evaluated the need for artificial roughness installations within recessed culverts in high gradient streams. Three sets of experiments were conducted examining: 1) the effect of sediment grain size, slope, and flow hydrograph on sediment transport through a single recessed box culvert, 2) the effect of bed roughness structures on sediment stability in a single recessed box culvert in high-gradient streams, and 3) the effect of culvert offset and skew on sedimentation in multi-barrel culverts.
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    Thinking Inside the Box (Culvert): Developing a Low-Cost, Easy-to-Install Retrofit Prototype for Fish Passage
    (Center for Transportation Studies, University of Minnesota, 2024-05) Kozarek, Jessica; Hernick, Matthew
    This project addresses a need to develop a low-cost, easy-to-install, and safe culvert retrofit for fish passage. Culverts can create barriers to fish movement due to fast-flowing water with no resting areas, shallow flow, and/or lack of cover. While new culvert design guidance addresses these concerns, many existing culverts have known fish passage issues that are not slated for replacement. We previously investigated a potential solution, using mussel spat rope, a fibrous plastic rope that has been demonstrated to facilitate fish passage in New Zealand. This design showed promise in laboratory, fish, and field trials. However, despite interest, concerns over the release of plastic into the environment have inhibited its use. Therefore, we leveraged this experience to investigate new solutions with benefits similar to the installation of mussel spat rope (i.e., low-flow resting areas, cover, and minimal impact to culvert capacity) but that are made with bio-based sustainable materials. The goals of this project were to 1) identify appropriate materials and 2) design and test protypes in flume experiments. We have several viable prototype designs ready for field-scale testing and/or deployment made with a range of non-plastic materials.