Port Huron Sga #4 Reservoir Report

Last Updated: December 5, 2025

Port Huron Sga #4, also known as Walker Flats, is a state-owned earth dam located in St.


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Summary

Clair County, Michigan. Built in 1966, this dam serves a primary purpose that is classified as "Other." It has a height of 10 feet and a hydraulic height of 9 feet, with a length of 1790 feet and a storage capacity of 180 acre-feet.

Despite being classified as having a low hazard potential, Port Huron Sga #4 has a moderate risk assessment rating of 3. The dam is currently in "Not Rated" condition assessment status, with the last inspection conducted in February 1994. The spillway type is uncontrolled, with a width of 9 feet, and the dam is located on a tributary to the Black River. Overall, this dam presents an interesting case study for water resource and climate enthusiasts, with opportunities for further exploration into its risk management measures and potential environmental impacts.

Year Completed

1966

Dam Length

1790

Dam Height

10

River Or Stream

Tributary to Black River

Primary Dam Type

Earth

Surface Area

45

Hydraulic Height

9

Nid Storage

180

Structural Height

10

Hazard Potential

Low

Nid Height

10
       
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.