OAR 350-082-0640: General Management Area Water Resources (Wetlands, Streams, Ponds, Lakes, and Riparian Areas) Criteria

(1) Wetlands Boundaries and Site Plans for Review Uses in Wetlands (a) If the proposed use is within a wetland or wetlands buffer zone, the applicant shall be responsible for determining the exact location of the wetland boundary. (A) The approximate location and extent of wetlands in the National Scenic Area is shown on the National Wetlands Inventory (U.S. Department of the Interior) as well as local wetlands inventories produced by state or local governments. In addition, the list of hydric soils and the soil survey maps shall be used as an indicator of wetlands. Some wetlands may not be shown on the wetlands inventory or soil survey maps. Wetlands that are discovered during an inspection of a potential project site shall be delineated and protected. (B) The project applicant shall be responsible for using the procedures specified in the Corps of Engineers Wetlands Delineation Manual (Wetlands Research Program Technical Report Y-87-1, on-line edition) and applicable Regional Supplements as may be revised from time to time. All wetlands delineations shall be conducted by a professional who has been trained to use the federal delineation procedures. (b) The Executive Director may verify the accuracy of, and may render adjustments to, a wetlands boundary delineation. If the project applicant contests the Executive Director’s verification or an adjustment, the Executive Director shall obtain professional services to render a final delineation, at the project applicant’s expense. (c) In addition to the information required in all site plans, site plans for proposed uses in water resources, or their buffer zones, shall include: (A) a site plan map prepared at a scale of one inch equals 100 feet (1:1,200), or a scale providing greater detail; (B) the exact boundary of the water resource, ordinary high water mark, or normal pool elevation, and the buffer zone; and (C) a description of actions that would affect the water resource. (2) Commission Rule 350-082-0640 shall not apply to proposed uses that would occur in the main stem of the Columbia River. The main stem of the Columbia River is defined by the Ordinary High Water Mark or Normal Pool Elevation and generally depicted on the map titled “Boundary Map, Columbia River Gorge National Scenic Area,” numbered NSA-001 and dated September 1986. This map is available at county planning departments and Gorge Commission and Forest Service offices. Backwaters and isolated water bodies created by roads and railroads are not part of the main stem of the Columbia River. (3) Review Uses in Wetlands. (a) The following uses may be allowed in wetlands, subject to compliance with 350-082-0600 through 350-082-0720 and subsection (b) below. (A) The modification, expansion, replacement, or reconstruction of serviceable transportation or other public infrastructure (this does not include private roads and driveways), if such actions would not: (i) Increase the size of an existing structure by more than 100 percent; (ii) Result in a loss of water resource functions; and (iii) Result in a loss of water quality, natural drainage, and fish and wildlife habitat. (B) The construction, modification, expansion, replacement, or reconstruction of minor water-related recreation structures that are available for public use. Structures in this category shall be limited to: boardwalks; observation decks; interpretative aids, such as kiosks and signs; and trails and paths, provided their surface is not constructed of impervious materials. (C) The construction, modification, expansion, replacement, or reconstruction of minor water-dependent structures that are placed on pilings, if the pilings allow unobstructed flow of water and are not placed so close together that they effectively convert an aquatic area to dry land. Structures in this category shall be limited to public and private docks and boat houses, and fish and wildlife management structures that are constructed by federal, state, or tribal government resource agencies. (b) The uses listed in subsection (a) above may be allowed only if they meet all of the following criteria: (A) Practicable alternatives for locating the structure outside of the wetland do not exist. (B) All reasonable measures have been applied to ensure that the use will result in the minimum loss of wetlands and in the minimum degradation of ecological functions, water quality, existing contour, vegetation, fish and wildlife resources, and hydrology. (C) The use will be constructed using best management practices. Best management practices can include measures to prevent soil erosion, the introduction and spread of invasive plants and aquatic species, and other impacts to plants, wildlife, soil, and water. Boardwalks and observation decks shall be constructed using non-toxic materials to protect water quality. (D) Areas disturbed during construction of the use will be rehabilitated to the maximum extent practicable. (E) The use complies with 350-082-0640(5)(b). (F) Proposed uses in wetlands shall be evaluated for adverse effects, including cumulative effects, and adverse effects shall be prohibited. (G) The use complies with all applicable federal, state, and local laws. (4) Review Uses in Water Resources (Except Wetlands), and Water Resource Buffer Zones (Including Wetlands Buffer Zones) (a) The following uses may be allowed in water resources (except wetlands), and may be allowed in all water resource buffer zones (including wetlands buffer zones), subject to compliance with 350-082-0600 through 350-082-0720 and subsection (b) below. (A) The modification, expansion, replacement, or reconstruction of serviceable structures, if such actions would not: (i) Increase the size of an existing structure by more than 100 percent; (ii) Result in a loss of water resources acreage or functions; (iii) Result in a loss of water quality, natural drainage, and fish and wildlife habitat; and (iv) Intrude further into water resources or water resources buffer zone. New structures shall be considered intruding further into a water resource or associated buffer zone if any portion of the structure is located closer to the water resource or buffer zone than the existing structure. (B) The construction, modification, expansion, replacement, or reconstruction of minor water-related recreation structures that are available for public use. Structures in this category shall be limited to: boardwalks; observation decks; interpretative aids, such as kiosks and signs; and trails and paths, provided their surface is not constructed of impervious materials. (C) The construction, modification, expansion, replacement, or reconstruction of minor water-dependent structures that are placed on pilings, if the pilings allow unobstructed flow of water and are not placed so close together that they effectively convert an aquatic area to dry land. Structures in this category shall be limited to public and private docks and boat houses, and fish and wildlife management structures that are constructed by federal, state, or tribal government resource agencies. (b) The uses listed in subsection (a) above may be allowed only if they meet all of the following criteria: (A) Practicable alternatives for locating the structure outside of the water resource or buffer zone do not exist. (B) All reasonable measures have been applied to ensure that the structure will result in the minimum alteration or degradation of ecological functions, water quality, existing contour, vegetation, fish and wildlife resources, and hydrology. (C) The structure will be constructed using best management practices. Best management practices can include measures to prevent soil erosion, the introduction and spread of invasive plants and aquatic species, and other impacts to plants, wildlife, soil, and water. Boardwalks and observation decks shall be constructed using non-toxic materials to protect water quality. (D) Areas disturbed during construction of the structure will be rehabilitated to the maximum extent practicable. (E) Proposed uses in water resources and their buffer zones shall be evaluated for adverse effects, including cumulative effects, and adverse effects shall be prohibited. (F) The structure complies with all applicable federal, state, and local laws. (5) Uses Not Allowed Outright or Listed in Guidelines (3)(a) and (4)(a) (a) Uses that are not allowed outright or listed in subsections (3)(a) and (4)(a) above, may be allowed in water resources (except wetlands) and in all water resources buffer zones (including wetland buffer zones), subject to compliance with 350-082-0600 through 350-082-0720 and subsection (b) below. These provisions do not apply to uses listed in subsections (3)(a) and (4)(a) that cannot meet the criteria in subsections (3)(b) and (4)(b). (b) The uses identified in subsection (a) above may be allowed only if they meet all of the following criteria: (A) The proposed use is water-dependent, or is not water-dependent but has no practicable alternative as determined by 350-082-0680. (B) The proposed use is in the public interest. All of the following factors shall be considered when determining if a proposed use is in the public interest: (i) The extent of public need for the proposed use. For uses in wetlands, public need is limited to uses necessary to alleviate a current public safety issue supported by evidence establishing the safety issue. (ii) The extent and permanence of beneficial or detrimental effects that the proposed use may have on the public and private uses for which the property is suited. (iii) The functions and size of the water resource that may be affected. (iv) The economic value of the proposed use to the general area. (v) The ecological value of the water resource and probable effect on public health and safety, fish, plants, and wildlife. (C) Measures will be applied to ensure that the proposed use results in the minimum feasible alteration of the resource. As a starting point, the following measures shall be considered when new development and uses are proposed in water resources or buffer zones: (i) Ecological functions, contour, and hydrology shall be maintained. Nonstructural controls and natural processes shall be used to the greatest extent possible. (ii) Construction shall occur during periods when fish and wildlife are least sensitive to disturbance. Work in streams, ponds, and lakes shall be conducted during the periods specified in Oregon or Washington state’s published guidelines for in-water work, or as advised by the applicable Department of Fish and Wildlife. (iii) All vegetation shall be retained to the greatest extent practicable, including wetland, aquatic, and riparian vegetation. (iv) Bridges, roads, pipelines and utility corridors, and other water crossings shall be minimized and should serve multiple purposes and properties. (v) Stream channels shall not be placed in culverts unless absolutely necessary for property access. Bridges are preferred for water crossings to reduce disruption to streams, ponds, lakes, and their banks. When culverts are necessary, oversized culverts with open bottoms that maintain the channel’s width and grade should be used. State agencies with permitting responsibility for culverts shall be consulted. (vi) Temporary and permanent control measures shall be applied to minimize erosion and sedimentation when water resource areas are disturbed, such as slope netting, berms and ditches, tree protection, sediment barriers, infiltration systems, and culverts. (vii) Measures shall be taken to prevent the introduction or spread of invasive plants or aquatic species. (D) Groundwater and surface-water quality will not be degraded by the proposed use. (E) Those portions of a proposed use that are not water-dependent or that have a practicable alternative will not be located in water resources or buffer zones. (F) The proposed use complies with all applicable federal, state, and local laws. (G) Areas that are disturbed during construction of the proposed use will be rehabilitated. When a project area cannot be completely restored or rehabilitated, such as when a boat launch permanently displaces aquatic and riparian areas, enhancement shall also be required. (H) Proposed uses in water resources and their buffer zones shall be evaluated for adverse effects, including cumulative effects, and adverse effects shall be prohibited. (I) Unavoidable impacts to water resources will be offset through the deliberate restoration, creation, or enhancement of impacted resources. Restoration, creation, and enhancement are not alternatives to the guidelines listed above; they shall be used only as a last resort to offset unavoidable water resource impacts. (J) Restoration, creation, and enhancement shall improve water quality, natural drainage, and fish and wildlife habitat of the affected wetland, stream, pond, lake, or buffer zone. When a project area has been disturbed in the past, it shall be rehabilitated to its natural condition to the maximum extent practicable. The following water resource guidelines shall apply: (i) Impacts to wetlands shall be offset by restoring or creating new wetlands or by enhancing degraded wetlands. Wetlands restoration shall be the preferred approach when wetlands are impacted. (ii) Water resources restoration and enhancement shall be conducted in accordance with a wetlands compensation plan or water resources mitigation plan. Voluntary enhancement project applications shall be encouraged. See 350-082-0460 and Part III, Chapter 4: Enhancement Strategies in the Management Plan. (iii) Water resources shall be replanted with native plant species that replicate the original vegetation community. (iv) Natural hydrologic conditions shall be replicated, including current patterns, circulation, velocity, volume, and normal water fluctuation. (v) Natural stream channel and shoreline dimensions shall be replicated, including depth, width, length, cross-sectional profile, and gradient. Riparian areas shall be rehabilitated to their original configuration, including slope and contour. (vi) The bed of the affected aquatic area shall be rehabilitated with materials appropriate for the channel and hydrologic features. (vii) Fish and wildlife habitat features shall be replicated, including pool-riffle ratios, substrata, and structural habitat features including large woody debris and boulders. (viii) Rehabilitation and enhancement efforts shall be completed no later than 90 days after the water resource or buffer zone has been altered, or as soon thereafter as is practicable. (ix) The size of replacement wetlands shall equal or exceed the following ratios. The first number specifies the required acreage of replacement wetlands, and the second number specifies the acreage of wetlands altered. (I) Restoration: 2:1 (II) Creation: 3:1 (III) Enhancement: 4:1 (x) Replacement wetlands shall replicate the functions of the wetlands that will be altered such that improvement of wetlands functions occurs. (xi) Replacement wetlands should replicate the type of wetland that will be altered. If this standard is not feasible or practical because of technical constraints, a wetland type of equal or greater benefit may be substituted, provided that improvement of wetlands functions occurs. (xii) Wetlands restoration, creation, or enhancement should occur within 1,000 feet of the affected wetland. If this guideline is not practicable because of physical, or technical constraints, replacement shall occur within the same watershed and as close to the altered wetland as practicable. (xiii) Restoration, creation, and enhancement efforts should be completed before a water resource is altered. If it is not practicable to complete all restoration, creation, and enhancement efforts before the water resource is altered, these efforts shall be completed before the new use is occupied or used. (xiv) Five years after a wetland is restored, created, or enhanced, or three years after a stream, pond, lake, or riparian area is restored, at least 75 percent of the replacement vegetation shall survive. The project applicant shall monitor the hydrology and vegetation of the replacement water resource, provide reports, and shall take corrective measures to ensure that it conforms with the approved wetlands compensation plan or water resources mitigation plan and this guideline. (6) Water Resources Buffer Zones (a) All water resources shall, in part, be protected by establishing undisturbed buffer zones as specified below. Except as otherwise allowed, water resources buffer zones shall be retained in their natural condition. When a buffer zone is disturbed by a new use, it shall be replanted with native plant species. (b) Buffer zones shall be measured outward from the bank full flow boundary for streams, the high water mark for ponds, lakes, the ordinary high water mark for the Columbia River below Bonneville Dam, the normal pool elevation for the main stem Columbia River above Bonneville Dam, and the wetland delineation boundary (see 350-082-0640(1) for wetland delineation boundary requirements) for wetlands. Measurement shall be on a horizontal scale that is perpendicular to the water resource boundary. (c) The project applicant shall be responsible for determining the exact location of the bank full flow boundary, high water mark, ordinary high water mark, normal pool elevation, or wetland delineation boundary. The Executive Director may verify the accuracy of and render adjustments to the applicant’s determination. If the project applicant contests the Executive Director’s verification or an adjustment, the Executive Director shall obtain professional services to render a final delineation, at the project applicant’s expense. (d) The width of wetlands, lakes, and ponds buffer zones shall be based on the dominant vegetation community that exists in a buffer zone. (A) The dominant vegetation community in a buffer zone is the vegetation community that covers the most surface area of that portion of the buffer zone that lies between the proposed activity and the affected wetland. Vegetation communities are classified as forest, shrub, or herbaceous. (i) A forest vegetation community is characterized by trees with an average height equal to or greater than 20 feet, accompanied by a shrub layer; trees must form a canopy cover of at least 40 percent and shrubs must form a canopy cover of at least 40 percent. A forest community without a shrub component that forms a canopy cover of at least 40 percent shall be considered a shrub vegetation community. (ii) A shrub vegetation community is characterized by shrubs and trees that are greater than three feet tall and form a canopy cover of at least 40 percent. (iii) A herbaceous vegetation community is characterized by the presence of herbs, including grass and grasslike plants, forbs, ferns, and nonwoody vines. (B) The following buffer zone widths wetlands, lakes and ponds shall be required: (i) Forest communities: 75 feet (ii) Shrub communities: 100 feet (iii) Herbaceous communities: 150 feet (e) The width of buffer zones for the following streams, identified by the Environmental Protection Agency in 2019 as priority cold water refuge fish habitat streams: Sandy River, Wind River, Little White Salmon, White Salmon, Hood River, Klickitat River, and Deschutes River, shall be 200 feet. (f) The width of buffer zones for streams used by anadromous or resident fish (tributary fish habitat), special streams, intermittent streams that include year-round pools, and perennial streams shall be 100 feet. (g) The width of buffer zones for intermittent streams, provided they are not used by anadromous or resident fish, shall be 50 feet. (7) Wetlands Compensation Plans. Wetlands compensation plans shall be prepared when a project applicant is required to restore, create, or enhance wetlands. A written plan addressing the guidelines in this section is also required for voluntary enhancement projects. All wetlands compensation plans must be approved by the Executive Director after consultation with federal and state agencies with jurisdiction over wetlands. They shall satisfy the following guidelines and any others required by federal and state agencies: (a) Wetlands compensation plans shall be prepared by a qualified professional hired by a project applicant. They shall provide for land acquisition, construction, maintenance, and monitoring of replacement wetlands. (b) Wetlands compensation plans shall include an ecological assessment of the wetland that will be altered and the wetland that will be restored, created, or enhanced. The assessment shall include information on flora, fauna, hydrology, and wetlands functions. (c) Compensation plans shall also assess the suitability of the proposed site for establishing a replacement wetland, including a description of the water source and drainage patterns, topography, wildlife habitat opportunities, and value of the existing area to be converted. (d) Plan view and cross-sectional, scaled drawings; topographic survey data, including elevations at contour intervals no greater than one foot, slope percentages, and final grade elevations; and other technical information shall be provided in sufficient detail to explain and illustrate: (A) Soil and substrata conditions, grading, and erosion and sediment control needed for wetland construction and long-term survival. (B) Planting plans that specify native plant species, quantities, size, spacing, or density; source of plant materials or seeds; timing, season, water, and nutrient requirements for planting; and where appropriate, measures to protect plants from predation. (C) Water-quality parameters, water source, water depths, water-control structures, and water-level maintenance practices needed to achieve the necessary hydrologic conditions. (e) A five-year monitoring, maintenance, and replacement program shall be included in all plans. At a minimum, a project applicant shall provide an annual report that documents milestones, successes, problems, and contingency actions. Photographic monitoring stations shall be established and photographs shall be used to monitor the replacement wetland. (f) A project applicant shall demonstrate sufficient fiscal, technical, and administrative competence to successfully execute a wetlands compensation plan. (8) Water Resources Mitigation Plans. Mitigation plans shall be prepared when a project applicant is required to rehabilitate or enhance a stream, pond, lake, or buffer zone. A written plan addressing the guidelines in this section is also required for voluntary enhancement projects. Plans shall satisfy the following guidelines and any others required by federal and state agencies: (a) Mitigation plans are the responsibility of the project applicant; they shall be prepared by qualified professionals. (b) All plans shall include an assessment of the physical characteristics and natural functions of the affected stream, pond, lake, or buffer zone. The assessment shall include hydrology, flora, and fauna. (c) Plans shall include plan view and cross-sectional, scaled drawings; topographic survey data, including elevations at contour intervals of at least two feet, slope percentages, and final grade elevations; and other technical information in sufficient detail to explain and illustrate: (A) Soil and substrata conditions, grading and excavation, and erosion and sediment control needed to successfully rehabilitate and enhance the stream, pond, lake, and buffer zone. (B) Planting plans that specify native plant species, quantities, size, spacing, or density; source of plant materials or seeds; timing, season, water, and nutrient requirements for planting; and where appropriate, measures to protect plants from predation. (C) Water quality parameters, construction techniques, management measures, and design specifications needed to maintain hydrologic conditions and water quality. (d) A minimum 3-year monitoring, maintenance, and replacement program shall be included in all mitigation plans. At a minimum, a project applicant shall prepare an annual report that documents milestones, successes, problems, and contingency actions. Three years after an aquatic area or buffer zone is rehabilitated or enhanced, at least 75 percent of the replacement vegetation shall survive. The project applicant shall monitor the replacement vegetation and take corrective measures to meet this guideline. Photographic monitoring shall be used to monitor all rehabilitation and enhancement efforts. (e) A project applicant shall demonstrate sufficient fiscal, administrative, and technical competence to successfully execute and monitor a mitigation plan.