South Lanesville Dike Reservoir Report

Last Updated: December 5, 2025

Located in New Milford, Connecticut, the South Lanesville Dike is a concrete gravity dam with a height of 20 feet and a length of 520 feet.


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Summary

Completed in 1929, this hydroelectric structure serves as a vital resource for the region, providing a maximum storage capacity of 172,000 acre-feet and a normal storage of 158,200 acre-feet. With a surface area of 5,600 acres and a drainage area of 40.4 square miles, the dam plays a crucial role in water management and recreational activities in the area.

Managed by the Federal Energy Regulatory Commission, the South Lanesville Dike is associated with six structures and has a high hazard potential. Despite its age, the dam has not undergone recent condition assessments but has an established emergency action plan. With a maximum discharge capacity of 2,280 cubic feet per second, the dam is designed to withstand potential risks and protect surrounding communities from flooding events. As a key component of the water resource infrastructure in the region, the South Lanesville Dike continues to play a significant role in ensuring water security and energy production.

Supported by federal regulations and inspections, the South Lanesville Dike exemplifies the importance of maintaining and monitoring critical water infrastructure. With its primary purpose of hydroelectric power generation, the dam serves as a valuable asset for the community while also offering recreational opportunities. As climate change impacts water resources and infrastructure, the South Lanesville Dike stands as a testament to the resilience and adaptability of water management systems in the face of evolving environmental challenges.

Year Completed

1929

Dam Length

520

Dam Height

20

River Or Stream

Rocky River

Primary Dam Type

Concrete

Surface Area

5600

Drainage Area

40.4

Nid Storage

172000

Hazard Potential

High

Nid Height

20
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
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Area Campgrounds

Location Reservations Toilets
South Lanesville Dike                                            SR3 Preview SR3
South Lanesville Dike                                            SR4 Preview SR4
South Lanesville Dike                                            SR2 Preview SR2
South Lanesville Dike                                            SR1 Preview SR1