The Alsea Watershed Study - Original and Revisited

The Alsea Watershed Study (44.5°N, 123.9°W), in the Oregon Coast Range, was the first paired-catchment study in the U.S. to simultaneously quantify the effects of forest harvesting on water quantity, water quality, and fish (habitat and populations). The Original Alsea study included seven years (1959-1965) of pre-harvest data and seven years (1967-1973) of post-harvest data. The study consisted of three small catchments, including Flynn Creek (reference), Needle Branch (clearcut harvested), and Deer Creek (patchcut with riparian buffers). The research clearly demonstrated the effectiveness of riparian areas at mitigating the effects of forest management activities on water quality (sediment, temperature, dissolved oxygen, nutrients) and aquatic ecosystem health. The results from this catchment study were critical in the development of the Oregon Forest Practices Act (1971/72), which provided the first rules associated with forest harvesting in the country. In 1990, the Alsea study was reactivated, and Needle Branch was harvested again, using current forest management practices, over two entries in 2009 and 2014. The Alsea Watershed Study Revisited provided a unique opportunity to quantify legacy effects from the historical (1960s) harvesting activity and to quantify and compare the effects of contemporary and historic forest harvesting practices. In our presentation we will provide a thorough overview, including site characteristics, data, experiments, and key findings from both the Original and Revisited Alsea Watershed Study, which has spanned almost six decades and provided many important insights to science, industry, and governmental organizations.