Arnold Reservoir Report
Last Updated: December 5, 2025
Arnold, located in Goshen, Wyoming, is a vital structure on the North Platte Offstream, designed by JOHN R LONG in 1968 for flood risk reduction.
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Summary
This Earth-type dam stands at 33 feet tall with a hydraulic height of 28 feet and a length of 300 feet, providing a maximum storage capacity of 2639 acre-feet and a normal storage of 1134 acre-feet. Despite its low hazard potential and fair condition assessment, Arnold has been deemed to have a moderate risk level.
Managed by a private owner, Arnold is under state jurisdiction and regulation, with permitting, inspection, and enforcement overseen by the State Engineer's Office in Wyoming. The dam features an uncontrolled spillway, one outlet gate, and a spillway width of 50 feet. Its primary purpose remains flood risk reduction, serving as a crucial infrastructure component in protecting the surrounding area from potential water-related disasters.
With its strategic location in Morrill, Nebraska, Arnold plays a significant role in mitigating flood risks and ensuring the safety of nearby communities. As a point of interest for water resource and climate enthusiasts, Arnold stands as a testament to the importance of effective dam infrastructure in managing water resources and enhancing resilience in the face of changing environmental conditions.
Year Completed |
1968 |
Dam Length |
300 |
Dam Height |
33 |
River Or Stream |
NORTH PLATTE OFFSTREAM |
Primary Dam Type |
Earth |
Surface Area |
227 |
Hydraulic Height |
28 |
Nid Storage |
2639 |
Structural Height |
33 |
Outlet Gates |
Uncontrolled - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
33 |
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.
Arnold