Bumping River

It flows down the east side of the Cascade Range, through Wenatchee National Forest and the William O. Douglas Wilderness.

Below the dam, the Bumping River continues flowing northeast.

It is joined by the American River, its main tributary, a few miles above its mouth where it joins the Little Naches River to form the Naches River.

Stockmen said that the river's name was given because during a freshet heavy boulders were carried down the river creating a rumbling vibration as the rocks kept bumping together.

[5] Variant names listed by the United States Geological Survey (USGS) for the Bumping River include Tancum River and Tanum River.