Swannanoa Lake #1 (South) Dam, located in Jefferson Township, Morris County, New Jersey, was completed in 1914 with a primary purpose of recreation.
Wind
Humidity
This masonry dam stands at a height of 15 feet and spans 228 feet in length, creating a reservoir with a storage capacity of 400 acre-feet. The dam is situated on the West Branch Rockaway River and is regulated by the New Jersey Department of Environmental Protection.
Despite its age, the dam is in satisfactory condition, with a high hazard potential due to its location and storage capacity. Regular inspections are conducted, with the last assessment completed in July 2021. The dam has a designated emergency action plan (EAP) with a recent revision in December 2021 to ensure readiness in case of a potential hazard or failure. The surrounding area has a drainage area of 13.9 square miles, and the reservoir covers 51 acres, providing a recreational space for the community while also serving important water resource management functions.
Year Completed |
1914 |
Dam Length |
228 |
Dam Height |
15 |
River Or Stream |
West Branch Rockaway River |
Primary Dam Type |
Masonry |
Surface Area |
51 |
Drainage Area |
13.9 |
Nid Storage |
400 |
Hazard Potential |
High |
Nid Height |
15 |