OAR 635-500-3400: Applicability

OAR 635-500-3400 through 635-500-3520 apply to the Sandy River basin. The Sandy River basin is defined as the Sandy River and its tributaries that originate high on the west and south slopes of Mount Hood, flow approximately 55 miles in a northwesterly direction and enter the Columbia River near Troutdale (Columbia RM 120.5). The Sandy River basin is situated in Multnomah and Clackamas counties, and drains approximately 508 square miles. The Sandy River basin is comprised of several subbasins, many of which are uniquely distinct hydrologically and geomorphologically. Principal tributaries include the Zigzag River, Still Creek, and Salmon River in the upper basin and Bull Run River, Gordon, Cedar, and Beaver creeks in the lower basin. Many other smaller tributaries located throughout the basin contribute significantly to streamflows and provide habitat for a wide array of fish and wildlife assemblages.