Lookout Reservoir Report
Nearby: 83 No 2 (Nid) Summit
Last Updated: December 7, 2025
Lookout is a federal-owned Earth dam located in Lyman, South Dakota, along Cedar Creek.
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Summary
Completed in 1938, this dam stands at 25 feet high with a length of 335 feet, providing a storage capacity of 40 acre-feet. While it has a low hazard potential and is currently rated as "Not Rated" for its condition assessment, Lookout serves as a key structure for water resource management in the region.
Managed by the St. Paul District of the US Army Corps of Engineers, Lookout plays a crucial role in regulating water flow and storage along Cedar Creek. Despite its age, the dam continues to serve its purpose effectively, with a maximum discharge capacity of 11 cubic feet per second. As climate change impacts water resources, structures like Lookout become increasingly important for maintaining water security and mitigating potential flood risks in the area.
With its historical significance and ongoing functionality, Lookout represents a blend of engineering excellence and environmental stewardship. As water resource and climate enthusiasts continue to monitor and assess the impact of climate change on water infrastructure, structures like Lookout serve as essential components in ensuring the sustainable management of water resources for future generations.
Year Completed |
1938 |
Dam Length |
335 |
Dam Height |
25 |
River Or Stream |
CEDAR CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Nid Storage |
40 |
Hazard Potential |
Low |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Lookout