Schedule for Engineering Design Plans for Dam Removal a. Within six (6) months of the final execution of Headgates Dam Demolition Agreement and Right of Entry Agreement with Somerset County, Xxxxxx Xxxxxx shall complete the necessary requirements of the Engineering Design Plan for Dam Removal (Technical Backup for Dam Safety Permit). Per the New Jersey Dam Safety Standards, N.J.A.C. 7:20-1.7(h), Xxxxxx Xxxxxx shall, as applicable and appropriate, develop the following data and information into a NJDEP Bureau of Dam Safety (Dam Safety) Technical Report for inclusion into the required NJDEP permit submittal: • Develop plans and HEC-RAS modeling computations for the breach2 including size, shape, and location of the initial breach and disposal of the spoil material; • Conduct sediment transport analyses using the HEC-RAS model to determine maximum allowable scour velocity during initial breaching. These data shall be used to control the release of sediment from the impoundment during and after the initial breach has been implemented, and to inform the timing for dewatering the impoundment. Nothing herein shall constitute a requirement that Xxxxxx Xxxxxx perform long-term sediment transport modeling; • Develop computations detailing the effects of the final breach on the downstream channel, including during 10, 50 and 100 year storms; • Identify the proposed work methods and demolition equipment and prepare a proposed work schedule for removing the Headgates Dam; • Provide a plan (scaled drawing) of the existing dam and lake along with surrounding property lines; • Identify the potential effects of the dam removal upon the environment, life and property downstream of the dam; 1 In the Bureau of Dam Safety file documentation, this dam is registered as NJ File No. 25-13. 2 The term “breach” in this Dam Safety context refers to the complete removal of the dam. Hereafter, the term “initial breach” refers to actions that begin the release of impounded water from above the dam and the “final breach,” means the complete removal of the dam. • Develop Construction Plans and Details (two sets/copies), including estimated as- built condition, river and dam cross-section profiles, and initial/final breach profile and plans for inclusion into the Dam Safety Permit.
