Hart, Robert J, Taylor, Howard E, Antweiler, Ronald C, Fisk, Greg G, Anderson, G M, Roth, D A, Flynn, Marilyn E, Peart, D B, Truini, Margot, and Barber, L B, 2005, Physical and chemical characteristics of Knowles, Forgotten, and Moqui Canyons, and effects of recreational use on water quality, Lake Powell, Arizona and Utah: United States Geological Survey.