G & J Heck No.2 Reservoir Report
Nearby: Brooks Dam R. Clark No.1
Last Updated: December 13, 2025
G & J Heck No.2 is a privately owned dam located in Dewey County, South Dakota, along the TR GRAND river.
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Summary
Built in 1954, this earth dam stands at a height of 25 feet and has a length of 400 feet, with a maximum storage capacity of 75 acre-feet and a normal storage capacity of 40 acre-feet. The dam is regulated and inspected by the South Dakota Department of Environment and Natural Resources (DENR), ensuring its structural integrity and operational safety.
Despite being classified as having low hazard potential, G & J Heck No.2 has not been rated for its condition assessment. The dam does not have an Emergency Action Plan (EAP) in place or updated inundation maps prepared. It is reassuring to note that the dam meets state jurisdictional requirements for permitting, inspection, and enforcement, highlighting a commitment to maintaining safety standards. With a maximum discharge capacity of 3660 cubic feet per second, G & J Heck No.2 plays a crucial role in water resource management and serves as an important infrastructure component in the region.
The presence of G & J Heck No.2 underscores the importance of monitoring and managing water resources in South Dakota. As climate change impacts become more pronounced, understanding the condition and functionality of such critical infrastructure becomes paramount. With its unique location and historical significance, G & J Heck No.2 stands as a testament to the ongoing efforts to balance water resource utilization with environmental preservation, ensuring a sustainable future for generations to come.
Year Completed |
1954 |
Dam Length |
400 |
Dam Height |
25 |
River Or Stream |
TR GRAND |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Nid Storage |
75 |
Hazard Potential |
Low |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Moreau R Near Whitehorse Sd
|
35cfs |
Grand R At Little Eagle Sd
|
47cfs |
Moreau R Near Faith Sd
|
14cfs |
Cedar Creek Nr Raleigh
|
20cfs |
Oak Cr Near Wakpala Sd
|
10cfs |
Cannonball River Nr Raleigh
|
40cfs |
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.
G & J Heck No.2