E.E Pettegrew Dam No.2 Reservoir Report

Last Updated: December 6, 2025

E.E Pettegrew Dam No.2, located in Fall River, South Dakota, was completed in 1910 and stands as a private earth dam along the TR-Cheyenne river system.


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Summary

With a dam height of 15 feet and a storage capacity of 160 acre-feet, this structure plays a vital role in water resource management in the region. The dam's primary purpose and associated structures are not specified, but its low hazard potential and "Not Rated" condition assessment indicate a relatively stable and safe infrastructure.

Managed by the South Dakota Department of Environment and Natural Resources (DENR), E.E Pettegrew Dam No.2 undergoes regular state inspections, permitting, and enforcement to ensure its continued functionality and safety. Despite lacking detailed information on emergency action plans and risk assessments, the dam's presence is significant for local water supply, flood control, and environmental conservation efforts. With a maximum discharge capacity of 420 cubic feet per second, the dam provides crucial support to the surrounding ecosystem and contributes to climate resilience in the area.

Overall, E.E Pettegrew Dam No.2 serves as a valuable water resource infrastructure in South Dakota, with its historical significance dating back over a century. As climate change impacts water availability and quality, the maintenance and regulation of such dams become increasingly important for sustainable water management practices. Enthusiasts and stakeholders in water resources and climate activism can appreciate the role of this dam in ensuring water security and environmental protection in the region.

Year Completed

1910

Dam Length

1500

Dam Height

15

River Or Stream

TR-CHEYENNE

Primary Dam Type

Earth

Hydraulic Height

10

Nid Storage

160

Hazard Potential

Low

Nid Height

15
       
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.