Hidden Hill Lake Dam Reservoir Report

Last Updated: December 5, 2025

Hidden Hill Lake Dam, located in New Palestine, Ohio, is a privately owned structure that serves as a recreational site for water and climate enthusiasts.


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Summary

The dam, completed in 1943, stands at a height of 31.7 feet and has a storage capacity of 99 acre-feet, with a normal storage level of 58 acre-feet. The dam is situated on Twelvemile Creek and is regulated by the Ohio Department of Natural Resources, ensuring regular inspections and enforcement of safety measures.

Despite its low hazard potential, Hidden Hill Lake Dam has a poor condition assessment as of its last inspection in April 2018. The dam covers a surface area of 7.6 acres and has a drainage area of 1.23 square miles, with a maximum discharge capacity of 799 cubic feet per second. While the dam lacks spillway infrastructure, it remains a popular location for recreational activities such as fishing, boating, and wildlife observation. With its scenic surroundings and historical significance, Hidden Hill Lake Dam continues to attract visitors and water resource enthusiasts alike.

As a key feature in Clermont County, Ohio, Hidden Hill Lake Dam plays a crucial role in water management and conservation efforts in the region. Despite its aging infrastructure and poor condition assessment, the dam remains operational and provides essential recreational opportunities for the local community. With ongoing inspections and regulatory oversight by the Department of Natural Resources, Hidden Hill Lake Dam stands as a testament to the importance of maintaining and preserving water resources in a changing climate.

Year Completed

1943

Dam Length

240

Dam Height

31.7

River Or Stream

TWELVEMILE CREEK

Primary Dam Type

Earth

Surface Area

7.6

Drainage Area

1.23

Nid Storage

99

Hazard Potential

Low

Nid Height

32
       
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.