Specifications include, but are not limited to: The project consists of gaining access and backfilling an erosion cavity at a spillway wingwall of the Tongue River Dam. The work generally consists of constructing a steep ramp in the near vertical bluff to facilitate access to the toe of the Tongue River Dam. Once access is established, loose and sloughed materials from the bluff will be removed down to a stable base, presently thought to be a sandstone bedrock layer near the water surface elevation of the river. All excavated materials will be removed to designated waste areas away from the river. A stable slope comprised of on-site sandy gravel and rock mulch plus some imported riprap will be constructed on the stable base, and a stable drain, backfill, and rock surface is to be placed in////////over the existing erosion cavity to stabilize the erosion.
