Cedar Grove Colony Dam Reservoir Report
Nearby: Sly Number 1 Joubert Drainage Dam
Last Updated: December 13, 2025
Cedar Grove Colony Dam, located in Brule, South Dakota, was completed in 1937 and stands as a testament to the Works Progress Administration's (WPA) design and construction.
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Summary
This private earth dam on TRIB. PLATTE CREEK has a height of 19 feet and a length of 300 feet, providing a storage capacity of 80 acre-feet. Despite its low hazard potential and moderate risk assessment, the dam's condition remains unrated, highlighting the need for further inspection and assessment.
Managed by the South Dakota Department of Environment and Natural Resources (DENR), Cedar Grove Colony Dam is subject to state regulation, permitting, inspection, and enforcement. The dam's primary purpose and associated structures are not specified, but its role in water resource management for the surrounding area is evident. With a maximum discharge capacity of 1523 cubic feet per second and an uncontrolled spillway width of 30 feet, the dam plays a crucial role in flood control and water storage for the region.
As climate change continues to impact water resources and infrastructure, the importance of maintaining and assessing dams like Cedar Grove Colony Dam cannot be understated. With Dusty Johnson (R) representing the area in Congress, there is a significant opportunity for collaboration and funding to ensure the continued safety and effectiveness of this essential water management structure in South Dakota.
Year Completed |
1937 |
Dam Length |
300 |
Dam Height |
19 |
River Or Stream |
TRIB. PLATTE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
19 |
Drainage Area |
3 |
Nid Storage |
80 |
Hazard Potential |
Low |
Nid Height |
19 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Platte Creek Near Platte
|
3cfs |
Firesteel Cr Near Mount Vernon Sd
|
0cfs |
White R Near Oacoma Sd
|
105cfs |
James R Near Mitchell Sd
|
659cfs |
James R Near Forestburg Sd
|
560cfs |
Niobrara River At Mariaville
|
1650cfs |
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.
Cedar Grove Colony Dam