Tanglewood Lake Dam Reservoir Report

Last Updated: December 5, 2025

Tanglewood Lake Dam, located in Geauga County, Ohio, is a privately owned structure with a primary purpose of recreation.


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Summary

Built in 1971, this earth dam stands at a height of 37.4 feet and has a storage capacity of 228 acre-feet. Situated along McFarland Creek, the dam spans 195 feet in length and covers a surface area of 17.4 acres.

Managed by the Department of Natural Resources in Ohio, Tanglewood Lake Dam is regulated, inspected, and enforced by the state to ensure its safety and compliance with standards. Despite being classified as having a high hazard potential, the dam's condition has been assessed as fair during the last inspection in June 2018. With a drainage area of 3.69 square miles and a maximum discharge of 26,100 cubic feet per second, the dam plays a crucial role in managing water resources in the region.

While Tanglewood Lake Dam presents risks due to its hazard potential, ongoing inspections and regulatory oversight help mitigate these concerns. As a vital infrastructure for recreational activities and water storage, the dam serves as a focal point for water resource and climate enthusiasts interested in understanding the intersection of human-made structures and natural ecosystems. With a commitment to safety and maintenance, Tanglewood Lake Dam continues to play a pivotal role in water management and conservation efforts in Ohio.

Year Completed

1971

Dam Length

195

Dam Height

37.4

River Or Stream

MCFARLAND CREEK

Primary Dam Type

Earth

Surface Area

17.4

Drainage Area

3.69

Nid Storage

228

Hazard Potential

High

Nid Height

37
       
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.