Minnesota Culvert Design Guidance for Aquatic Species Passage and Stream Connectivity

Principal Investigator(s):

Matthew Hernick, Associate Engineer, SAFHL - Hydraulic Lab


  • Jeff Marr, Associate Director, SAFHL - Hydraulic Lab
  • John Nieber, Professor, Bioproducts and Biosystems Engineering

Project summary:

Minnesota has ~92,000 miles of streams and rivers and 142,000 miles of roads. Minnesota streams and rivers are an integral part of our state's natural and economic landscape. These two networks intersect numerous times, often with a stream passing beneath the roadway in a culvert. Historically, these crossings have been designed with the safe passage of roadway traffic in mind, but recently there has been wide acknowledgement that allowing for passage of stream "traffic" (fish and other aquatic organisms) is also important to maintain the aquatic connectivity of in-stream habitat. Culverts can become barriers when conditions exceed fish or aquatic organism abilities with: excessive drop at outlet, insufficient pool depth, excess flow velocity, excessive turbulence, or behavioral barriers. Although a number of published resources on aquatic organism passage design exist, there is no single guide to inform designers which solutions are appropriate and effective in Minnesota. The design of culverts to accommodate aquatic organism passage (AOP) requires an understanding of organism habitat requirements, swimming abilities, and migration needs, as well as an understanding of how a culvert design will perform in a specific geomorphic and hydrologic context. Due to the variety of eco-regions found in Minnesota, culvert geometries, and other factors, it is not likely that there is a single solution to accommodate aquatic organism passage through culverts. This project is mining expert knowledge and synthesizing existing AOP documents to develop a Minnesota culvert design guidance for aquatic species passage and stream connectivity.

Project details:

  • Project number: 2017013
  • Start date: 06/2016
  • Project status: Completed
  • Research area: Environment and Energy