Clackamas River Basin Water-Quality Assessment

Science Center Objects

Starting in 1997, the USGS began routinely studying water resources in the Clackamas River Basin. Whether it be assessing harmful algal blooms, runoff issues, streamflow, or watershed health, the USGS has worked with its partners to maintain one of Oregon's most beloved rivers.

The Clackamas River in northwestern Oregon is valued for its scenic beauty, recreational opportunities, salmon and steelhead runs, and for providing a high-quality source of drinking water. From its headwaters in the Cascade Range between Mount Hood and Mount Jefferson, the upper Clackamas River descends 7,200 feet on a northwesterly course, winding through steep canyons and gorges and cutting through promi­ nent basalt outcrops and cliffs. The many falls and rapids, separated by deep, clear pools and expansive cobble bars, make the upper Clackamas River a favorite among whitewater enthusiasts, anglers, and hikers. Downstream from Estacada, the river emerges into gentler terrain, forming a broad floodplain that is confined by steep cliffs that form upland terraces in places. Here, the lower Clackamas River is wider, flowing past volcanic buttes in the lower basin before meeting the Willamette River south of Portland.

Water quality in the Clackamas River is consid­ered very good to excellent compared to other rivers in the State and has withstood pressures from human impacts and natural disturbances seemingly well. However, urban development and human activities continue to affect the water-quality of the Clackamas River and it's tributaries. The USGS monitors the watershed and investigates current stream conditions, ecological health, channel change and water quality.