Owned and operated by UYWCD, the Stillwater Ditch primarily delivers agricultural releases from Yamcolo Reservoir and Stillwater Reservoir across the Five Pines Mesa. The Stillwater Ditch serves irrigators with original water rights, shareholders of Stillwater Reservoir storage, the Yamcolo Irrigators Association, and municipal and agricultural storage contract holders from Yamcolo Reservoir.
With a capacity of 62.5 cubic feet per second (cfs), the Stillwater Ditch allows irrigators and municipalities whose diversions are not along the Bear River to contract stored water from Yamcolo Reservoir. While there is a small municipal contract that can be delivered via the Stillwater Ditch, the primary use of water deliveries through the ditch are agricultural uses including livestock and irrigation. Agricultural operations across the Five Pines Mesa depend on water deliveries through the Stillwater Ditch to enhance and extend their irrigation season beyond spring runoff each year.