Merrill Karlen #1 Reservoir Report

Last Updated: December 13, 2025

Merrill Karlen #1 is a privately owned earth dam located in Lyman, South Dakota, with a height of 28 feet and a length of 400 feet.


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Summary

Completed in 1954, this dam has a maximum storage capacity of 23 acre-feet and a normal storage capacity of 20 acre-feet. With a low hazard potential and a condition assessment of "Not Rated," Merrill Karlen #1 is regulated by the South Dakota Department of Environment and Natural Resources (DENR) and is subject to state permitting, inspection, and enforcement.

Managed by the Natural Resources Conservation Service, Merrill Karlen #1 serves as a vital structure for water resource management in the area, with a maximum discharge capacity of 2100 cubic feet per second. Situated on the TR-MISSONot RatedI river or stream, this dam plays a crucial role in flood control and water supply for the surrounding communities. Despite its age, Merrill Karlen #1 continues to function effectively, ensuring the safety and sustainability of water resources in the region.

Owned by a private entity, Merrill Karlen #1 is a key component of the local water infrastructure, contributing to the overall resilience and adaptability to climate change impacts in the area. As a low-hazard dam with a history of reliable performance, this structure represents a valuable asset for water resource and climate enthusiasts seeking to understand and support sustainable water management practices in South Dakota.

Year Completed

1954

Dam Length

400

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

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.