Rock Mountain Lake Reservoir Report

Last Updated: December 5, 2025

Rock Mountain Lake, also known as Pawnee Reservoir, is a private water supply dam located in Jefferson County, Alabama.


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Summary

Built in 1936, this Earth-type dam stands at 49 feet tall with a hydraulic height of 43 feet. It has a storage capacity of 254 acre-feet, with a normal storage level of 184 acre-feet. The dam is situated on the TR-Barton Branch river, within the jurisdiction of the Mobile District of the US Army Corps of Engineers.

Despite being privately owned, Rock Mountain Lake serves as a significant water source for the surrounding area. With a maximum discharge rate of 296 cubic feet per second, the dam plays a crucial role in water supply management for the region. While the dam's hazard potential is considered significant, its condition assessment has not been rated, highlighting the need for ongoing monitoring and maintenance to ensure its continued safety and functionality.

For water resource and climate enthusiasts, Rock Mountain Lake offers a fascinating example of early 20th-century dam engineering and its importance in providing essential water supply services. As a key infrastructure in Alabama's water management system, this dam serves as a reminder of the delicate balance between human development and environmental sustainability in the face of changing climate conditions.

Year Completed

1936

Dam Length

1838

River Or Stream

TR-BARTON BRANCH

Primary Dam Type

Earth

Hydraulic Height

43

Nid Storage

254

Structural Height

49

Hazard Potential

Significant

Nid Height

49
       
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.