Canyon Lake Dam Reservoir Report

Last Updated: December 5, 2025

Canyon Lake Dam in Rapid City, South Dakota, stands as a critical structure for water resource management and climate resilience in the region.


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Summary

Completed in 1976, this earth dam on Rapid Creek serves multiple purposes, including flood control, water storage, and recreation. With a height of 23 feet and a storage capacity of 610 acre-feet, the dam plays a vital role in regulating water flow and mitigating flood risks in the area.

Owned and regulated by the local government with oversight from the South Dakota Department of Agriculture and Natural Resources, Canyon Lake Dam is subject to regular inspections to ensure its structural integrity and safety. Despite being classified as having a high hazard potential, the dam is currently assessed as being in fair condition, with a comprehensive Emergency Action Plan in place to address any potential risks or emergencies. The dam's location in Pennington County, South Dakota, highlights its importance in safeguarding the surrounding communities and environment from the impacts of extreme weather events and changing climate patterns.

With a maximum discharge capacity of 50,000 cubic feet per second and a drainage area of 66 square miles, Canyon Lake Dam exemplifies the critical role that infrastructure plays in managing water resources and adapting to climate challenges. As climate change continues to impact the frequency and intensity of extreme weather events, dams like Canyon Lake play a crucial role in protecting communities, supporting water supply needs, and enhancing overall resilience in the face of a changing climate landscape.

Year Completed

1976

Dam Length

1325

Dam Height

23

River Or Stream

RAPID CREEK

Primary Dam Type

Earth

Hydraulic Height

23

Drainage Area

66

Nid Storage

610

Hazard Potential

High

Nid Height

23
       
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.