141-089-0810 Wetland Ecosystem Improvement – Authorized Projects Projects are limited to the following. (1) Vegetation Management. Ground-altering activities needed to reestablish and maintain native vegetation, such as mechanized land clearing to remove nonnative vegetation and disking for seedbed preparation and planting of native wetland species is allowed. (2) Floodplain Contouring. Floodplain contouring of wetland terraces to reconnect a waterway to an adjacent wetland or expand the area of seasonal inundation is allowed. This project does not include modification of a stream channel. (3) Microtopography Establishment. Grading and contouring to reestablish microtopography (e.g., hummocks, minor ridges, very shallow depressions) in areas that have been previously leveled, scalped, or otherwise disturbed to eliminate preexisting microtopography is allowed. The project is limited to six-inch maximum elevation rise or drop. (4) Macrotopography Establishment. Shallow excavation to create scrapes, basins, meanders, and swales that do not exceed two feet in depth from existing or original ground surface and have minimum side slopes of 6:1 or gentler is allowed. If shallow excavation is combined with berm construction described in section (6) of this rule, the maximum depth of inundation must not exceed two feet. (5) Removal of Materials. Removal of soil or other materials that have been placed in a wetland for the purpose of restoring or improving the natural and/or historical topography is allowed. (6) Low Earthen Berms and Spillways. Construction of low earthen berms and vegetated spillways that impede, contain, or direct surface water may be used to extend the area or duration of shallow inundation. The design height of the berms must be no more than 18 inches from the existing ground level and have a maximum top width of four feet, variable slopes at a minimum of 6:1 or gentler on the water side, and maximum slopes of 6:1 on the land side, unless gentler slopes do not result in the conversion of wetland to upland. These structures may be installed to manipulate seasonal water depth, duration and degree of fluctuation that would be characteristic of natural or historical hydrologic conditions and to manage invasive species. When berms are combined with shallow excavation described in section (4) of this rule, the maximum depth of inundation must not exceed two feet. (7) Removal of Structures. Removal of diversion structures, water control structures, berms, and tidegates, as long as the removal does not cause water to rise or be redirected in such a manner to result in damage to structures or substantial property is allowed. (8) Placement of Temporary Exclusion Fencing in Wetlands. Where necessary to protect plantings from herbivores, temporary exclusion fencing may be placed in wetlands. (9) Maintenance and Reconstruction of Wetland Ecosystem Improvement Structures. Removal and fill necessary to maintain or reconstruct the serviceability of existing, man-made wetland ecosystem improvement structures not otherwise exempted by OAR 141-085-0534 is allowed. The terms “maintenance” and “reconstruction” have the same meanings as in OAR 141-085-0510. Statutory/Other Authority: ORS 196.600 - 196.692 & 196.795 - 196.990 Statutes/Other Implemented: ORS 196.600 - 196.692 & 196.795 - 196.990 History: DSL 2-2024, amend filed 05/31/2024, effective 07/01/2024 DSL 31-2018, minor correction filed 01/03/2018, effective 01/03/2018 DSL 2-2011, f. & cert. ef. 3-1-11