M&E developed a Supplemental Watershed Plan and Environmental Assessment (EA) for the rehabilitation of Clear Fork Dam 33. This was necessitated by the change in classification from a low hazard dam to a high hazard dam. This project was prepared in accordance with Principles & Guidelines (P&G), National Environmental Plan Act (NEPA), Environmental Laws, and the NRCS National Watershed Program Manual (NWPH). Computer programs TR 20 and HEC-RAS were used for the hydrology and hydraulic analysis of the watershed and TCEQ Full Dam Breach procedure was used for the breach analysis of Clear Fork Dam 33 to determine hazard classification and inundation areas. Stage-Storage area relationships were determined from available LIDAR data combined with a bathometric survey of the pool area. SITES was utilized to evaluate the existing and alternative dam/spillway configurations for capacity, conformance to TR 60 requirements, and to assess the stability and integrity of the existing vegetated auxiliary spillway. Modifications of the existing vegetated spillway in combination with various structural roller compacted concrete (RCC) spillway widths were developed using SITES to identify the most economical rehabilitation alternative. The knowledge and experience of the planning team were important to the success of developing the Supplemental Watershed Plan and EA as per, P&G, NEPA, and NRCS requirements. Alternative plans formulated and evaluated were No Action or Future Without Project, Decommission, Low Hazard Dam with Non-Structural measures, and Rehabilitation of Clear Fork 33. Public participation letters and notices were prepared for distribution and publication and public meetings held. Federal and State agencies and Tribal communities were invited to consult on the project and attend public meetings.
Principal Spillway outlet channel
Auxiliary Spillway crest section
Principal Spillway Normal Pool
Principal Spillway Riser
Dam, Riser, and Normal Pool
Dam and Normal Pool