Harrington Reservoir Report
Nearby: Fairview Extension Sandstone Dam
Last Updated: December 5, 2025
Harrington, also known as Enl of 4629r, is a privately owned earth dam located in Greybull, Wyoming, along the Manny Draw river or stream.
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Summary
Completed in 1974, this irrigation dam stands at a height of 30 feet with a hydraulic height of 25 feet and a length of 1817 feet. It has a storage capacity of 2126 acre-feet and a surface area of 185 acres, serving the purpose of irrigation for the surrounding area.
Despite its significant hazard potential and poor condition assessment, Harrington is regulated, permitted, inspected, and enforced by the Wyoming State Engineer's Office. The dam features an uncontrolled spillway with a width of 100 feet and an outlet gate valve - 1. With a moderate risk assessment rating of 3, there are no emergency action plans in place, highlighting a need for improved risk management measures for this essential water resource infrastructure.
Located in Big Horn County, Harrington plays a crucial role in water management and agricultural activities in the region. As climate change continues to impact water resources, it is essential to ensure the safety and efficiency of dams like Harrington to sustainably meet the irrigation needs of the community while mitigating potential risks and adapting to changing environmental conditions.
Year Completed |
1974 |
Dam Length |
1817 |
Dam Height |
30 |
River Or Stream |
MANNY DRAW |
Primary Dam Type |
Earth |
Surface Area |
185 |
Hydraulic Height |
25 |
Drainage Area |
2 |
Nid Storage |
2126 |
Structural Height |
30 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Bighorn River At Basin
|
996cfs |
Bighorn River At Kane
|
1340cfs |
Bighorn R At Worland Wyo
|
4350cfs |
Greybull River At Meeteetse
|
338cfs |
Shell Creek Near Shell
|
74cfs |
Shoshone River Near Lovell
|
460cfs |
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.
Harrington