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