Alexander Reservoir Report

Last Updated: December 6, 2025

Alexander is a gravity dam located on the Wisconsin River in Merrill, Wisconsin, with a primary purpose of hydroelectric power generation.


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Summary

Built in 1913, this historic structure stands at a height of 38 feet and has a maximum storage capacity of 6600 acre-feet, serving as a critical water resource in the region. The dam's spillway, with a width of 338 feet, is controlled to manage water flow and prevent flooding, showcasing its importance in water resource management.

Managed by the Federal Energy Regulatory Commission, Alexander is a key player in providing clean energy and recreational opportunities in the area. With a hazard potential rated as high and a risk assessment indicating a very high risk level, the dam's safety and structural integrity are closely monitored. Despite its age, Alexander continues to play a vital role in water resource management, highlighting the importance of maintaining and investing in our existing infrastructure to ensure a sustainable and resilient future for our water resources and climate.

Year Completed

1913

Dam Length

1481

Dam Height

38

River Or Stream

Wisconsin River

Primary Dam Type

Gravity

Surface Area

803

Hydraulic Height

23

Drainage Area

2520

Nid Storage

6600

Structural Height

40

Outlet Gates

Tainter (radial) - 11

Hazard Potential

High

Foundations

Rock

Nid Height

40
       
Seasonal Comparison

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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.