What materials should be used for constructing causeways and cofferdams in a watercourse?

Using non-erodible materials for constructing causeways and cofferdams in a watercourse is essential for ensuring stability and minimizing environmental impact. Non-erodible materials help prevent soil and sediment from being washed away during high water flows, which can lead to increased sedimentation in the watercourse and surrounding areas. These materials are typically more durable against the forces of water than earthen fill, which can become saturated and unstable, especially during storm events or high flow conditions.

Moreover, non-erodible materials can include options such as rock, concrete, or other engineered products specifically designed to withstand water flow and resist erosion. This choice promotes long-term effectiveness and safety of the structure, aids in maintaining water quality, and aligns with best management practices as outlined in Erosion and Sediment Control guidelines.

In contrast, earthen fill may be prone to erosion and instability when exposed to water, while the use of any available materials can lead to unauthorized or ineffective construction practices that ultimately compromise the structure's integrity. Plastic coverings, although offering temporary protection in some cases, do not provide the necessary structural support or erosion resistance needed for these applications.