First Reservoir Dam in Thiells, New York, is a state-regulated earth dam constructed in 1917 for the primary purpose of water supply.
Wind
Humidity
With a height of 46 feet and a length of 650 feet, this dam has a storage capacity of 116 acre-feet and a surface area of 6 acres. Located on Horse Chock Brook in Rockland County, the dam is owned and regulated by the New York State Department of Environmental Conservation (NYS DEC), ensuring state permitting, inspection, and enforcement for its operations.
Despite being classified as having a high hazard potential and poor condition assessment, the dam continues to provide essential water resources to the surrounding area. The spillway type is uncontrolled with a width of 30 feet, and the dam is situated within a drainage area of 1.98 square miles. The last inspection in June 2019 revealed the dam's need for improvement, highlighting the importance of regular maintenance and monitoring to ensure the safety and functionality of this critical infrastructure.
With its historical significance and vital role in water supply management, First Reservoir Dam serves as a focal point for water resource and climate enthusiasts interested in understanding the complexities of dam infrastructure and its impact on local communities. As efforts to enhance risk management measures and address maintenance issues continue, the dam remains a key component of the region's water supply infrastructure, emphasizing the importance of sustainable practices and proactive stewardship of natural resources.
Year Completed |
1917 |
Dam Length |
650 |
Dam Height |
46 |
River Or Stream |
HORSE CHOCK BROOK |
Primary Dam Type |
Earth |
Surface Area |
6 |
Drainage Area |
1.98 |
Nid Storage |
116 |
Hazard Potential |
High |
Nid Height |
46 |