Later dams at North Fork, Oak Grove, Stone Creek, and Timothy Lake also intercepted wood sediment on the lower river.

About 61 miles (98 km) from the mouth, Granite Creek enters from the left, and the river flows by Austin Hot Springs and Picnic Area.

Shortly thereafter, Switch Creek enters from the right, and at about 57 miles (92 km) from the mouth, the Clackamas receives the Collawash River from the left.

[6][7] The river then flows by Bonnie Lure State Recreation Area, which lies to the north, and receives Eagle Creek from the right about 17 miles (27 km) from the mouth.

It receives Goose Creek from the right before passing Barton County Park, which lies north of the river about 3 miles (5 km) downstream of Bonnie Lure.

[6][7] Before 1800, coniferous forests covered most of the watershed, and its streams supported big populations of salmon, steelhead, and other fish.

Native Americans hunted, fished and gathered food and materials in the Clackamas River drainage as early as 10,000 years ago.

This was home to the Clackamas tribe, a subgroup of the Chinookan speakers who lived in the Columbia River valley from Celilo Falls to the Pacific Ocean.

Remnants of the tribe continued to travel from the Warm Springs Indian Reservation to fish and to gather berries near Estacada through the 1930s.

[8] The Clackamas River Basin Council, with diverse representatives from over 20 stakeholder groups, fosters partnerships with organizations and private individuals to advocate natural resource conservation and preserve the watershed for future generations.

Stakeholders include (but are not limited to) those involved in agriculture, education, fish and wildlife, hydropower, recreation, timber production, and government agencies.

The watershed is home to the last significant run of wild late-winter coho salmon in the Columbia Basin, which generally spawn on the main stem of the Clackamas above the North Fork Reservoir.

The watershed also has one of only two remaining runs of spring chinook in the Willamette basin and supports a significant population of winter steelhead, cutthroat trout, and native lamprey.

The protected portion of the Clackamas features five categories of resources that are considered to be "outstandingly remarkable", defined by the NWSRS as having "importance to the region or nation".

[11] In March 2008, the United States Geological Survey (USGS) released a report entitled "Pesticide Occurrence and Distribution in the Lower Clackamas River Basin, Oregon, 2000–2005."