Annual Winter Drawdown Schedule

December 01, 2025| Community, Environment

By: Holly Odgers

Each year the water level on Lake Hopatcong is lowered to allow for waterfront maintenance and to protect private property from ice damage. The lake level is managed by Hopatcong State Park staff through adjustments in the four sluice gates at the dam within the park. These adjustments are made in accordance with the New Jersey Department of Environmental Protection’s (NJDEP) Lake Hopatcong Water Level Management Plan, which was updated in 2024.

The updated plan still calls for a 26-inch annual drawdown and a 60-inch drawdown every five years. However, the 22-inch drawdown pilot program, first introduced in 2016, will continue to remain in effect and now appears as Appendix E (page 50) within the Plan. The pilot program temporarily supersedes the 26-inch drawdown described in the plan and is designed to improve the likelihood of a successful spring refill while maintaining downstream ecological protection.

2025 Drawdown Schedule  

The drawdown initiation dates are determined by assessing recent rainfall and current lake levels. Due to this fall’s unusually dry weather, the lake level has already declined significantly. State Park officials will initiate the drawdown as necessary to meet the 22-inch target, or a gage height of 7.16 feet, by December 15. The graph below displays the timeline and water level targets for the drawdown process. The U.S. Geological Survey (USGS) monitors water level, outflow, and rain data on Lake Hopatcong. Their data can be viewed HERE. 

The water level will then be maintained until a spring thaw has softened the ice on the lake sufficient to avoid ice damage to private property. Once the spring thaw is underway, the flow will be reduced at the dam to a level to both maintain sufficient flow to the Musconetcong River and allow refill of the lake, given adequate rainfall, to the elevation of 9 feet.