We performed Independent Consultant Dam Safety Inspections and Potential Failure Mode Analyses, in accordance with Federal Energy Regulatory Commission (FERC) Part 12D regulations for Brookfield Renewable Effley, High Falls, and Taylorville projects New York State. The scope of the project included:
Design and Operational Documentation Review – To prepare for the inspections, we reviewed previous Safety Inspection Reports, Potential Failure Modes Analyses, Dam Safety Surveillance and Monitoring Plan and Report (DSSMP & DSSMR) and the Supporting Technical Information Document (STID) for each development. Documentation/data reviewed as part of the STID included: H&H data and analysis; stability analysis; geology and seismicity, surveillance data, dam break studies, construction and rehabilitation history, standard operating procedures, and operational data. One of the Projects included an extensive review and update of foundation strength parameters and a proposed methodology for determining the capacity of post-tensioned anchors in the project structures. Concrete in the original powerhouse at one of the projects was evaluated for the effects of alkali-aggregate reactivity.
Potential Failure Modes Analysis – We conducted PFMA sessions in accordance with FERC guidelines with a cross functional team of Brookfield and FERC personnel including members of the Compliance and Operations groups as well as the Dam Safety Engineer. The development of each Potential Failure Mode (PFM) included: 1) a review/assessment of the sequence of conditions and events that would lead to that particular PFM; 2) a review/assessment of the risk reduction opportunities for each PFM; and, 3) a review/assessment of the Surveillance and Monitoring Plan that should be implemented for each PFM.
Dam Safety Inspection – We performed a visual inspection of each dam to identify any potential safety issues. The inspections were performed in accordance with FERC Part 12D requirements for each element of the project. Inspections included the spillway, abutments, embankment, gravity sections, crest, intake structure, powerhouse, penstocks, conveyance system, and all appurtenant features. Aterra prepared a detailed report with findings and recommendations which was subsequently submitted to FERC for review and approval.