The Yakima River above the Naches confluence is nearly 100 miles long, and drains nearly twice as much area as the Naches drainage. Much of the mainstem of the Upper Yakima has relatively low gradient with extensive floodplains that once contained multiple channels and large areas of spawning and rearing habitat for salmonids, as around the towns of Easton, Cle Elum, Ellensburg and Selah. Other reaches run through large bedrock canyons between Cle Elum and Ellensburg, and Ellensburg and Selah. The mainstem Yakima, Teanaway River and Swauk Creek support most of the current steelhead use in the Upper Yakima population area. A number of other tributaries to the Upper Yakima River (e.g., Wilson, Naneum, Big, Little, Taneum, Manastash, Tucker, Cooke, Caribou, Coleman, and Reecer creeks) are likely to have historically supported steelhead, but impassable dams, dry reaches below dams and unscreened diversions have greatly reduced or eliminated steelhead use of these tributaries. The upper watershed contains three natural glacial lakes that have been converted to serve as storage reservoirs; historically accessible habitat above Cle Elum, Kachess and Keechelus dams has been unavailable to steelhead since the early 20th century.