Gus Allen 2 Reservoir Report
Nearby: Gus Allen 1 Merrill Karlen #2
Last Updated: December 13, 2025
Gus Allen 2 is a privately owned earth dam located in Lyman, South Dakota, completed in 1956.
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Summary
With a height of 28 feet and a length of 330 feet, this dam serves the primary purpose of water resource management. Managed by the Natural Resources Conservation Service, this structure has a maximum storage capacity of 23 acre-feet and a normal storage capacity of 20 acre-feet. The dam has a low hazard potential and its condition is currently rated as "Not Rated".
Situated on the TR-MISSONot RatedI river or stream, Gus Allen 2 is regulated by the South Dakota Department of Environment and Natural Resources for permitting, inspection, and enforcement. While the dam has not been modified in recent years and lacks specific hazard assessment or emergency action plans, it remains an important component of the local water infrastructure. With a maximum discharge capacity of 425 cubic feet per second, this dam plays a crucial role in managing water flow and mitigating flood risks in the area.
For water resource and climate enthusiasts, Gus Allen 2 offers a fascinating example of privately owned water infrastructure in South Dakota. As a key element in the state's water management system, this dam highlights the importance of regulatory oversight, maintenance, and emergency preparedness in ensuring the safety and effectiveness of such structures. With its low hazard potential and historical significance, Gus Allen 2 serves as a reminder of the ongoing need for sustainable water resource management practices in the face of changing environmental conditions.
Year Completed |
1956 |
Dam Length |
330 |
Dam Height |
28 |
River Or Stream |
TR-MISSONot RatedI |
Primary Dam Type |
Earth |
Hydraulic Height |
28 |
Nid Storage |
23 |
Hazard Potential |
Low |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
White R Near Oacoma Sd
|
105cfs |
Bad R Near Fort Pierre Sd
|
7cfs |
White River Near White River
|
42cfs |
Little White R Below White River Sd
|
141cfs |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Iron Nation - Lake Sharpe
|
||
West Bend State Rec Area - Pierre
|
||
Byre Lake Recreation Area
|
Gus Allen 2