Moll Lake Dam Reservoir Report

Last Updated: December 5, 2025

Moll Lake Dam, located in Columbia Hills Corners, Ohio, is a private earth dam completed in 1940 with a primary purpose of recreation.


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Summary

It stands at a height of 32.2 feet and has a storage capacity of 56.8 acre-feet. The dam's reservoir covers an area of 5 acres and drains a watershed of 0.39 square miles, with a maximum discharge rate of 127 cubic feet per second.

Despite its significant hazard potential, Moll Lake Dam is currently in poor condition, as assessed during the last inspection in 2018. The dam is regulated by the Ohio Department of Natural Resources, with permitting, inspection, and enforcement responsibilities falling under the state jurisdiction. The dam poses a potential risk to the surrounding area, prompting the need for a comprehensive risk assessment and management plan to ensure the safety of downstream communities and the integrity of the dam structure.

As a critical component of the local water resource management infrastructure, Moll Lake Dam serves as a recreational hub for the community while also playing a vital role in flood control and water supply management. With its historical significance dating back to the 1940s, efforts must be made to address its poor condition and mitigate any potential risks associated with its operation to safeguard both the environment and public safety.

Year Completed

1940

Dam Length

275

Dam Height

32.2

River Or Stream

TRIBUTARY TO WEST BRANCH ROCKY RIVER

Primary Dam Type

Earth

Surface Area

5

Drainage Area

0.39

Nid Storage

56.8

Hazard Potential

Significant

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.