Assessment of Embedded Culvert Low Flow Hydraulics

In 2010, New Hampshire adopted new rules for the permitting of stream crossings. One aspect of the new rules was that new culverts should be geomorphically sized and preferably have natural materials located at the stream crossing stream bed to better accommodate the passage of aquatic and other organisms. In culverts that are not open bottom, this means oversizing the culvert and partially filling the bottom with natural material. This partially filled culvert is known as an embedded culvert. Often the material placed in the embedded culvert is specifically sized to match the native material in the stream as well as to be stable. Very coarse sediments are needed for stability, and, at low flows, the water can completely disappear into these sediments leaving no aquatic habitat. While culverts are recommended to be embedded, the practice is criticized for its impact on aquatic habitat. The proposed research had two thrusts: to study constructed embedded culverts in New Hampshire and to complete literature reviews and interviews with other states that require embedded culverts. For the field monitoring portion embedded culverts at various ages were inspected and the bed sediments were sampled for particle size distribution analysis and comparison to that of the design when available. Aquatic organism passage was assessed at low flows. The products of this research provide a diagnosis of the issue, real or perceived, and the elements of bed sediment design leading to successful embedded culverts that provide passage for aquatic organisms.

• Record URL:
  • https://mm.nh.gov/files/uploads/dot/remote-docs/nhdot-research-26962y-2022-report.pdf
• Record URL:
  • https://rosap.ntl.bts.gov/view/dot/61001
• Corporate Authors:

  University of New Hampshire, Durham

  Department of Civil and Environmental Engineering
  Durham, NH  United States 

  New Hampshire Department of Transportation

  Bureau of Materials and Research
  Box 483, 5 Hazen Drive
  Concord, NH  United States  03302-0483

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Sawosik, Ben
  • Carter, Chloe
  • Ballestero, Thomas
• Publication Date: 2022-2

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Illustrations; Maps; Photos;
• Pagination: 46p

Subject/Index Terms

• TRT Terms: Aquatic life; Culverts; Hydraulics; Streambeds; Streamflow
• Geographic Terms: New Hampshire
• Subject Areas: Bridges and other structures; Environment; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 01839347
• Record Type: Publication
• Report/Paper Numbers: FHWA-NH-RD-26962Y
• Contract Numbers: 26962Y, A004(856)
• Files: NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Mar 23 2022 10:51AM