Chapelle Reservoir Report
Nearby: J. Harter Harter Pond Dam
Last Updated: December 12, 2025
Chapelle, a state-owned Earth dam located in Hyde, South Dakota, was completed in 1937 by the Works Progress Administration (WPA).
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Summary
This structure spans 500 feet in length and stands at a height of 20 feet, with a storage capacity of 625 acre-feet. The dam serves the primary purpose of flood control along Chapelle Creek, with a drainage area of 28 square miles and a maximum discharge capacity of 2,233 cubic feet per second.
Despite being categorized as having a low hazard potential, Chapelle is subject to state regulation and inspection, with the South Dakota Department of Agriculture and Natural Resources overseeing its enforcement and permitting processes. The dam's last inspection was conducted in September 2019, with a moderate risk assessment rating of 3. While its condition assessment is currently listed as "Not Rated," the structure's emergency action plan (EAP) status and risk management measures remain unclear, highlighting potential areas for further evaluation and improvement to ensure public safety and water resource management.
This historical dam, designed by the WPA and owned by the state of South Dakota, serves as a crucial infrastructure for flood control and water storage in the region. With its uncontrolled spillway and moderate risk assessment, ongoing monitoring and maintenance are essential to safeguard the surrounding communities and ecosystems from potential hazards. The data on Chapelle's design, construction, and regulatory oversight provide valuable insights for water resource and climate enthusiasts interested in the intersection of infrastructure management and environmental sustainability.
Year Completed |
1937 |
Dam Length |
500 |
Dam Height |
20 |
River Or Stream |
CHAPELLE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Drainage Area |
28 |
Nid Storage |
625 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Bad R Near Fort Pierre Sd
|
7cfs |
White R Near Oacoma Sd
|
105cfs |
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.
Chapelle