Soil Saver Wall Performance and Potential Modifications for Aquatic Organism Passage

Reinforced concrete box (RCB) culverts are designed to provide hydraulic conveyance at peak stream discharge for low initial and long-term maintenance costs; however, these structures can pose challenges to aquatic organism passage (AOP) at some locations. A number of states are using a variety of methods for the construction of RCB culverts that facilitate the passage of aquatic organisms. Culverts constructed using stream simulation methods, roughened channels, and inclusion of baffles are some of the methods used to promote AOP. One of the issues with RCB culverts is the potential for erosion to develop upstream of the culvert (headcutting). The Kansas Department of Transportation (KDOT) constructs soil saver walls on RCB culverts to prevent headcutting. The hydraulic efficiency of culverts with soil saver walls is usually acceptable. However, soil saver walls act as a drop inlet and can hinder AOP. Therefore, KDOT is considering modifications to the soil saver wall design to further promote AOP. Thirty states were surveyed to evaluate current RCB culvert applications and headcutting prevention practice and how AOP was addressed. Most of these states had problems with headcutting due to box culverts. Some of these states used a soil saver wall-type structure to control headcutting in the form of a rock or gabion weir, stone wall, concrete wall, or embedment formation. These features may include a V-notch. Some states use upstream riprap. Some states are facing regulatory issues regarding AOP. Most states with upstream weirs that act as drop inlets have redesigned or are in the process of redesigning those structures to facilitate AOP. Fifteen existing RCB culverts in Kansas with soil saver walls were surveyed; seven of these are discussed in this report. Most of these culverts were in excellent condition. There was very little to no headcutting observed and the culverts appeared to be functioning well. It did appear they could potentially act as a barrier to AOP. Flume testing was conducted in the Water Resources Lab at the University of Kansas on models of a conventional box culvert with a standard soil saver wall configuration, a wall with a square notch, and a wall with a V-notch. It was observed that excellent performance for the control of grade was provided by the soil saver wall for both the standard and notched walls. The V-notch wall appeared to have the potential to provide for better AOP for low flows, therefore this configuration is preferred.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 79p

Subject/Index Terms

Filing Info

  • Accession Number: 01596815
  • Record Type: Publication
  • Report/Paper Numbers: K-TRAN: KU-14-2
  • Contract Numbers: C1984
  • Files: NTL, TRIS, ATRI, STATEDOT
  • Created Date: Mar 31 2016 7:34AM