The water source is Toats Coulee Creek at a point some 15 miles northwest of Tonasket. Toats Coulee Diversion Dam is a concrete structure with an ogee overflow section, and headworks for the main supply canal. This also required a concrete gated outlet structure to divert water into the Spectacle Lake Canal. Two larger pumping plants are located on Spectacle Lake. Distribution is made through about 27 miles of lined and unlined laterals.
Most lands are sprinkler irrigated, with each farm providing the pressure required.
Fish screens are included at Spectacle Lake outlet works and at the two larger pumping plants. Chelan The Chelan Division, Manson Unit, has been authorized and constructed. The unit is located in Chelan County, bordering the north shore of the lower end of Lake Chelan, about 40 miles up the Columbia River from Wenatchee. Spectacle Lake Dike Spectacle Lake Dike is part of the Whitestone Coulee Unit, Okanogan - Similkameen Division, Chief Joseph Dam Project. Spectacle Lake Dike forms an offstream regulatory reservoir.