Monitoring

Each autumn Fall Creek Lake is drawn down to allow endangered juvenile salmonids to pass freely through the dam. The drawdowns involve lowering the lake water level to the lake bed, creating a fluvial environment characterized by large amounts of sediment being transported through the dam and into Fall Creek and the Middle Fork Willamette River.

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.

Drinking water for the city of Eugene, Oregon, is drawn from the McKenzie River, a high-quality source that is nonetheless threatened by urban, agricultural, and forestry land uses upstream as well as by changes in water management in the watershed. In 2002, the USGS began monitoring dissolved pesticides in the McKenzie River and its tributaries.

Environmental flows are defined as "streamflow needed to sustain ecosystems while continuing to meet human needs."

From 1986 to 2009, the USGS studied various aspects of watershed health in the Yakima River Basin. The results from these studies have been published and are available online.

Marmot Dam on the Sandy River was removed in 2007 as part of decommissioning of Portland General Electric’s Bull Run Hydroelectric Project. Removal of the 15-meter-tall dam would allow the Sandy River to flow freely for the first time in nearly 100 years and make upstream habitat more accessible to anadromous fish.