Ida Lake Dam – Existing Condition and Proposed Drawdown Plan Gregory Daviero, PhD, PE Michael Quinn, PE October 30, 2018
Tonight’s Agenda • Existing conditions • Previous failure of dam • Proposed drawdown • Long term solutions • Next steps
Project Drivers • NYCRR Part 673 covers activities related to ownership of dams - Promulgated August 19, 2009 - Inspection and Maintenance Plan (I&M) - Engineering Assessment (EA) • FEMA funded project - Damaged during Hurricane Irene - Intended to repair left and right abutments • Inspection revealed an unsafe condition
Site Location Ida Lake Dam Ida Lake
Existing Conditions • Timber dam – 135 ft long, 12 ft high • 28 crosswise supports spaced at 5 ft on center • Foundation is concrete slab on bedrock
September 14, 2018 Inspection • Bents in good to fair condition • Spanning timbers in fair to very poor condition Area of significant cracking • Bents underneath dam • Failing spanning timbers
January 1998 Dam Failure (from NYS DEC Files) • Failure in January 1998 • Approximately 30 feet wide • Top: Dam • Right: Dam shortly after Shortly before failure reconstruction (February, 1998) (Summer, 1999)
Existing Lake Elevation
Proposed Lake Lowering Plan (Looking Downstream)
Proposed Lake Lowering Plan (Looking Upstream)
Existing Lake Elevation
Anticipated Lake Elevation
Site after 1997 Drawdown
Permitting • NYS DEC Dam Safety • US Army Corps of Engineers • NYS DEC Region 4
Long Term Solutions • Decommissioning (Removal) • Replace with a more resilient structure (not wood) • Replace with a more resilient structure at a lower crest elevation
Next Steps • Lower Pool • Collection of site topography • Deliberations on the future of the structure • Community meeting for presentation on options
Questions? Gregory Daviero, PhD, PE Michael Quinn, PE October 30, 2018
Regulated Waters and Wetlands • NYSDEC - Poesten Kill regulated as a Class C waterway • Supporting fisheries and non-contact recreation - No mapped wetlands • Federal Wetlands - Forested - Open Water
Federally Regulated Waters and Wetlands • NYSDEC Ida Lake Dam - Poestenkill regulated as a Class C waterway • Supporting fisheries and non-contact recreation - No mapped wetlands • Federal Wetlands - Forested - Open Water
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