Dimock Reservoir Report
Nearby: Ethan Moench Dam
Last Updated: December 12, 2025
Dimock is a state-owned dam located in Hutchinson, South Dakota, with a history dating back to its completion in 1937 by the Works Progress Administration (WPA).
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Summary
This earth dam stands at a height of 30 feet and has a storage capacity of 1900 acre-feet, serving the purpose of regulating the flow of the TRJAMES river. Despite being categorized as low hazard potential and not yet rated for condition assessment, Dimock is under the regulatory oversight of the South Dakota Department of Agriculture and Natural Resources (DANR), with regular inspections conducted every three years to ensure its safety and functionality.
Situated in the St. Paul District of South Dakota, Dimock plays a crucial role in managing water resources and mitigating potential flood risks in the region. The dam's spillway, equipped with uncontrolled discharge capabilities and vertical lift outlet gates, can handle a maximum flow of 7100 cubic feet per second. While the dam has not undergone recent modifications or received an official Emergency Action Plan (EAP) assessment, its moderate risk assessment rating suggests the need for proactive risk management measures to safeguard downstream communities in case of emergencies. As climate change impacts continue to pose challenges to water resource management, Dimock stands as a key infrastructure asset in ensuring the resilience of the local watershed.
Year Completed |
1937 |
Dam Length |
960 |
Dam Height |
30 |
River Or Stream |
TRJAMES |
Primary Dam Type |
Earth |
Hydraulic Height |
30 |
Drainage Area |
105 |
Nid Storage |
1900 |
Outlet Gates |
Vertical Lift |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
30 |
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.
Dimock