J Janssen #1 Reservoir Report
Nearby: Russiff #1 Ness #1
Last Updated: December 6, 2025
J Janssen #1 is a privately owned irrigation dam located in Powder River, Montana along the picturesque Hay Creek.
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Summary
Built in 1940 by the USDA NRCS, this earth dam stands at a height of 16 feet and spans 480 feet in length, providing a maximum storage capacity of 151 acre-feet. With a low hazard potential, this dam serves the primary purpose of irrigation, supporting agricultural activities in the region.
Managed by the Montana Department of Natural Resources and Conservation (DNRC), J Janssen #1 is regulated, permitted, inspected, and enforced to ensure its structural integrity and safety. Although its condition assessment is currently not rated, the dam's emergency action plan (EAP) status, risk assessment, and inundation maps preparation are pending updates. Situated in a remote area with a distance of 39 miles from the city of Mizpah, J Janssen #1 contributes to water resource management and climate resilience efforts in the region.
As part of the Omaha District under the US Army Corps of Engineers, J Janssen #1 plays a crucial role in supporting irrigation activities in Powder River County. With its historical significance dating back to the mid-20th century, this dam stands as a testament to the collaboration between federal and state agencies in ensuring sustainable water resource management. As water resource and climate enthusiasts, the data surrounding J Janssen #1 offers a glimpse into the intricate network of regulatory frameworks and engineering marvels that underpin our water infrastructure systems.
Year Completed |
1940 |
Dam Length |
480 |
Dam Height |
16 |
River Or Stream |
HAY CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
16 |
Drainage Area |
15.38 |
Nid Storage |
151 |
Hazard Potential |
Low |
Nid Height |
16 |
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.
J Janssen #1