Willoughby Reservoir Report

Last Updated: December 6, 2025

Willoughby is a state-regulated earth dam located in Madison, Tennessee, with a structural height of 30 feet and a hydraulic height of 18.5 feet.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 1994, this dam serves multiple purposes, including storage and flood control, with a maximum storage capacity of 380 acre-feet and a normal storage capacity of 150 acre-feet. The dam covers a surface area of 26 acres and has a drainage area of 0.98 square miles, making it a crucial structure for water resource management in the region.

With a low hazard potential and a satisfactory condition assessment as of October 2018, Willoughby is regularly inspected by the Tennessee Safe Dams Program to ensure its continued safety and functionality. The dam is equipped with an uncontrolled spillway and has no outlet gates. Its risk assessment has been categorized as moderate, indicating a moderate level of risk associated with the structure. Overall, Willoughby plays a vital role in the local water resource infrastructure, mitigating flood risks and providing essential water storage for the surrounding area.

Year Completed

1994

Dam Length

1060

Primary Dam Type

Earth

Surface Area

26

Hydraulic Height

18.5

Drainage Area

0.98

Nid Storage

380

Structural Height

30

Outlet Gates

None

Hazard Potential

Low

Nid Height

30
       
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.