The Skok floods so much because its filling in with excess bottom sediments. During high flows the channels not deep enough and there's no where for the water to go but over the banks. I believe the principal culprit are the Lake Cushman Dams on the North Fork. The dams act to regulate flow on about 50 percent of the basin, substantially lowering peak storm flows, which would blow out excess sediments during the winter. Increased siltation from agriculture and logging likely contributes to the condition as well.