Tongue River Dam Spillway Stilling Basin Erosion Repair

The project consists of gaining access and backfilling an erosion cavity at a spillway wingwall of the Tongue River Dam 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. The project is owned by the DNRC and operated by the Tongue River Water User's Association. The Work shall be Substantially Completed by November 11, 2022. Anticipated Notice to Proceed date is September 16, 2022 and will not be later than October 3, 2022 Question Submission Close Date 7/24/2022 5:00 PM MDT

Division 02 -	Existing Conditions, Subsurface Investigation.
Division 31 -	Earthwork, Site Clearing, Grading, Excavation and Fill, Subgrade Preparation, Excavation, Shoring, Tunneling and Mining, Tunnel Excavation.
Division 35 -	Waterway and Marine Construction, Dam Construction and Equipment.