Mainline 1 Reservoir Report

Last Updated: December 6, 2025

Mainline 1 is a privately owned irrigation dam located on Maury Creek in Crook County, Oregon.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 1969, this earth dam stands at a height of 57 feet and has a storage capacity of 500 acre-feet, with a normal storage level of 445 acre-feet. The dam plays a crucial role in providing water for agricultural irrigation in the region, covering a drainage area of 5.96 square miles.

With a significant hazard potential and a moderate risk assessment rating, Mainline 1 is subject to regular inspections by the Oregon Water Resources Department to ensure its structural integrity and safety. The dam features a slide (sluice gate) outlet for water release and an uncontrolled spillway type. Although the condition assessment is currently 'Not Rated', the dam's emergency action plan status and risk management measures are not specified in the available data.

As an essential component of the local water resource infrastructure, Mainline 1 serves as a vital resource for sustaining agricultural activities in the area. Its strategic location and design highlight the importance of proper maintenance and monitoring to mitigate potential risks and ensure the continued availability of water for irrigation purposes in the region.

Year Completed

1969

Dam Length

460

Dam Height

57

River Or Stream

MAURY CREEK

Primary Dam Type

Earth

Surface Area

20.5

Hydraulic Height

55

Drainage Area

5.96

Nid Storage

500

Structural Height

57

Outlet Gates

Slide (sluice gate)

Hazard Potential

Significant

Nid Height

57
       
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.