New York State Department of Environmental Conservation (NYSDEC) -- Elizabethtown, New York
Located in Elizabethtown, New York, Kingdom Dam was an Intermediate Hazard Class “B” dam, impounding Lincoln Pond. CHA performed a dam hazard assessment, hydrologic and hydraulic evaluation and a dam stability analysis, which concluded: the dam should be reclassified to a High Hazard Class “C” dam; the current spillway configuration could not pass the flows associated with the spillway design flood, 50% of the Probable Maximum Flood; and the dam did not meet factors of safety for overturning stability as required by NYSDEC Dam Safety Guidelines.
CHA assessed three spillway modification options to address the spillway flow and stability deficiencies. The selected option minimized costs and reduced environmental impacts. The option modified the dam to extend the spillway from 45 to 110 feet long, raised the crest of the dam by 6 feet, and installed post-tensioned ground anchors into bedrock to meet the stability requirements.
CHA developed plans, specifications and a permit application package to rehabilitate the dam. CHA provided technical engineering support and construction observation throughout construction.
Services Provided by CHA:
- Dam Safety Inspection
- Geotechnical Investigation
- Stability Analysis
- Hydrologic and Hydraulic Evaluation
- Dam Hazard Assessment
- Wetland Delineation
- Permit Application Preparation
- Hydraulic Design
- Spillway Design
- Erosion and Sediment Control Design
- Dam Safety Design
- Concrete Design
- Construction Observation