Glastowbury Reservoir Report

Last Updated: December 6, 2025

Glastowbury is a privately owned dam located in Cumberland, Tennessee, with a primary purpose of recreation.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1979, this earthen dam stands at a structural height of 98.1 feet and has a hydraulic height of 89.8 feet, impounding the Trail Branch river. With a normal storage capacity of 2400 acre-feet and a maximum storage of 2880 acre-feet, Glastowbury covers a surface area of 53 acres and drains an area of 1.95 square miles.

Managed by the Tennessee Safe Dams Program, Glastowbury is classified as having a significant hazard potential but is currently in satisfactory condition as of the last inspection in October 2020. While the spillway is uncontrolled, the dam has no outlet gates or associated structures. The risk assessment for Glastowbury is moderate (3), indicating a level of risk that warrants attention and management measures to ensure the safety and integrity of the dam.

Located within the Nashville District and under state jurisdiction, Glastowbury serves as a vital recreational resource in the area. Its presence not only provides opportunities for outdoor activities but also highlights the importance of proper dam management and maintenance to mitigate risks and ensure the safety of surrounding communities and the environment.

Year Completed

1979

Dam Length

570

River Or Stream

TRAIL BRANCH

Primary Dam Type

Earth

Surface Area

53

Hydraulic Height

89.8

Drainage Area

1.95

Nid Storage

2880

Structural Height

98.1

Outlet Gates

None

Hazard Potential

Significant

Nid Height

98
       
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.