"Oregon's Removal-Fill Law (ORS 196.795-990) requires people who plan to remove or fill material in wetlands or waterways to obtain a permit from the Department of State Lands. This permit is broadly referred to as the “Removal-Fill Permit.” The law applies to all landowners, whether private individuals or public agencies.
The purpose of the law, enacted in 1967, is to ensure protection and the best use of Oregon’s water resources for home, commercial, wildlife habitat, public navigation, fishing and recreational uses.
In most cases, a permit is required if an activity will involve filling or removing 50 cubic yards or more of material in a wetland or waterway. For activities in state-designated Essential Salmonid Habitat, State Scenic Waterways and compensatory mitigation sites, a permit is required for any amount of removal or fill." -Department of State Lands Website