The purposes of this chapter are to:

A.    Comply with Title 13 and Title 3 of Metro’s Urban Growth Management Functional Plan while balancing resource protection with property rights and development needs.

B.    Protect or improve water quality by filtering sediment and pollutants and absorbing excess nutrients for the protection of public health, safety and the environment and to comply with both state and federal laws and regulations, including the Clean Water Act and the Endangered Species Act.

C.    Moderate storm water impacts by slowing, storing, filtering and absorbing storm water and to maintain storm water storage and conveyance to prevent or minimize flooding and erosion for the protection of public health and safety.

D.    Prevent erosion and minimize sedimentation of water bodies by protecting root masses along streams that resist erosion and stabilize the stream bank and by protecting vegetation on steep slopes to maintain their stability.

E.    Protect and improve the following functions and values of WRAs that enhance the value of fish and wildlife habitat:

1.    Natural stream corridors that provide habitat and habitat connectivity for terrestrial wildlife;

2.    Microclimate habitats that support species adapted to those conditions;

3.    Shade to maintain healthy stream temperatures;

4.    Vegetation to absorb and filter pollution and sediment that would otherwise contaminate the water body;

5.    Sources of organic material that support the food chain;

6.    Recruitment of large wood that enhances the habitat of fish bearing streams;

7.    Moderation of stream flow by storing and delaying storm water runoff; and

8.    Vegetated areas surrounding wetlands that, together with the wetland, provide vital habitat for birds, amphibians, and other species.

F.    Provide mitigation standards and guidance to address water quality values and ecological functions and values lost through development within WRAs.

G.    Encourage the use of habitat friendly development practices.

H.    Minimize construction of structures and improvements where they are at risk of flooding, to enable natural stream migration and channel dynamics, and protect water resources from the potential harmful impacts of development.

I.    Provide for uses and activities in WRAs that have negligible impact on such areas; and to provide for other uses that must be located in such areas in a way that will avoid or, when avoidance is not possible, minimize potential impacts. (Ord. 1623 § 1, 2014)

A.    This chapter applies to all development, activity or uses within WRAs identified on the WRA Map. It also applies to all verified, unmapped WRAs. The WRA Map shall be amended to include the previously unmapped WRAs.

B.    The burden is on the property owner to demonstrate that the requirements of this chapter are met, or are not applicable to the land, development activity, or other proposed use or alteration of land. The Planning Director may make a determination of applicability based on the WRA Map, field visits, and any other relevant maps, site plans and information, as to:

1.    The existence of a WRA;

2.    The exact location of the WRA; and/or

3.    Whether the proposed development, activity or use is within the WRA boundary.

In cases where the location of the WRA is unclear or disputed, the Planning Director may require a survey, delineation, or sworn statement prepared by a natural resource professional/wetland biologist or specialist that no WRA exists on the site. Any required survey, delineation, or statement shall be prepared at the applicant’s sole expense. (Ord. 1623 § 1, 2014)

Alteration, development, or use of real property designated as, and within, a WRA is strictly prohibited except as specifically allowed or exempted in this chapter.

1    Development to within 50 feet of the water resource applies to Table 32-2 WRA types (A), (C), (D), and (H). Development behind top of slope (ravine) applies to WRA type (B).

(Ord. 1623 § 1, 2014)

The following development, activities or uses are exempt from a WRA permit but must conform to any applicable requirements of this section.

A.    Vegetation maintenance, planting and removal.

1.    The routine maintenance of any existing WRA, consistent with the provisions of this chapter such as, but not limited to, removing pollutants, trash, unauthorized fill, and dead or dying vegetation that constitutes a hazard to life or property.

2.    Removal of plants identified as nuisance, invasive or prohibited plants; provided, that after plant removal, re-vegetation of disturbed areas is performed pursuant to CDC 32.100.

3.    The planting or propagation of plants identified as native plants on the Portland Plant List.

4.    Maintenance of existing gardens, pastures, lawns, and landscape perimeters, including the installation of new irrigation systems within existing gardens, lawns, and landscape perimeters.

5.    The use of pesticides and herbicides with applicable state (e.g., Oregon DEQ) permits.

B.    Building, paving, grading, and testing.

1.     Maintenance. Routine repair, maintenance and replacement of legally established above and below ground utilities and related components (including storm water catch basins, intakes, etc.), roads, driveways, paths, trails, fences and human-made water control facilities such as constructed ponds, wastewater facilities, and storm water treatment facilities that do not expand the disturbed area at grade or footprint, provided re-vegetation of disturbed areas or corridors is performed pursuant to CDC 32.100.

2.    Trails. The establishment of unpaved trails constructed of non-hazardous, pervious materials with a maximum width of four feet in generalized corridors approved in a parks or trails master plan; provided, that:

a.    The trail is set back from the water resource at least 30 feet, except at stream crossing points or at points were the topography forces the trail closer to the stream.

b.    Foot bridge crossings shall be kept to a minimum. When the stream bank adjacent to the foot bridge is accessible (e.g., due to limited vegetation or topography), fences or railings shall be installed from the foot bridge and extend 15 feet beyond the terminus of the foot bridge to discourage trail users and pets from accessing the stream bank, disturbing wildlife and habitat areas, and causing vegetation loss, stream bank erosion and stream turbidity.

c.    Trails shall be designed to minimize disturbance to existing vegetation, work with natural contours, avoid the fall line on slopes where possible, and avoid areas with evidence of slope failure to ensure that trail runoff does not create channels in the WRA.

3.    Site investigations. Temporary and minor clearing outside of wetlands not to exceed 200 square feet per acre or site, whichever is more; provided, that no individual area is greater than 200 feet in size, for the purpose of site investigations and pits for preparing soil profiles; provided, that such areas are restored to their original condition when the investigation is complete. While such temporary and minor clearing is exempt from the provisions of this chapter, it is subject to all other City codes, including provisions for erosion control and tree removal.

4.    Support structures for overhead power or communication lines where the support structures are outside of the WRA.

5.    The installation, within the developed portions of street rights-of-way, of new utilities, the maintenance or replacement of existing utilities and street repaving projects.

C.    Non-conforming structures.

1.    Expansion of the principal non-conforming structure. Additions to the existing building footprint of a principal non-conforming structure within, or partially within, the WRA are exempt, and additionally exempt from Chapter 66 CDC, Non-Conforming Structures, as long as the addition(s) meets the following restrictions:

a.    Re-vegetation of temporarily disturbed areas will be performed per CDC 32.100 after the addition is completed;

b.    There is no net increase in storm water runoff flowing toward the water resource as a result of the addition(s);

c.    The addition to the principal structure is not closer to the water resource than the existing principal structure;

d.    If it is a lateral addition, it does not extend more than 25 feet laterally from the side of the existing principal structure;

e.    The addition does not increase the footprint of the existing principal structure by more than 500 square feet, at any one time or incrementally;

f.    Lateral additions to decks cannot come closer to the water resource than the existing deck;

g.    Vertical additions to existing principal structures that comply with the maximum height requirements of the underlying zone are exempt.

2.    Repair, replacement and removal of non-conforming structures.

a.    Interior remodeling of a non-conforming structure.

b.    Repair, maintenance, rehabilitation and replacement of non-conforming structures, accessory structures, utilities and related components, roads, driveways, paths, trails, fences, and human-made water and storm water control facilities that do not expand the disturbed area or footprint. Re-vegetation of temporarily disturbed areas or corridors pursuant to CDC 32.100 is required.

c.    This section also applies in the event that a non-conforming structure burned down or was otherwise damaged by natural or other disaster. The structure could be re-built so long as the structure did not expand the original footprint and the original access driveway (PDA) was used.

d.    Demolition and removal of non-conforming structure’s impervious surfaces are exempt as long as the affected areas are restored with native vegetation pursuant to CDC 32.100.

D.    New construction activities allowed in the WRA.

1.    Structures shall be located out of the WRA, except that eaves, balconies, decks, “pop outs,” and similar additions, may cantilever over the outer boundary of the WRA a maximum of five feet. No vertical supports may extend down to grade within the WRA.

2.    Construction of an accessory structure, less than 120 square feet in size and under 10 feet tall, may be constructed to within 50 feet of the water resource or 10 feet behind the top of slope (ravine, per Figure 32-4), whichever is greater. No more than one accessory structure is permitted in the WRA. Accessory structures in the WRA that existed prior to January 1, 2006, may remain in place and not count against the limitation in new accessory structures.

3.    Construction of a water permeable patio or deck within 30 inches of the original grade and construction of approved water permeable footpaths may be constructed to within 50 feet of the water resource or 10 feet behind the top of slope (ravine, per Figure 32-4), whichever is greater.

4.    Fences may be built to within 50 feet of the water resource or behind the top of slope (ravine), whichever is greater.

Figure 32-1: Additions to Non-Conforming Principal Structures within the WRA Boundary

E.    Emergency activities. Actions authorized by the City Manager that must be taken immediately or within a period of time too short to fully comply with this chapter to:

1.    Prevent immediate danger to life or property;

2.    Prevent immediate threat of serious environmental degradation;

3.    Restore existing utility service; or

4.    Reopen a public thoroughfare to traffic.

However, after the emergency has passed any disturbed area shall be restored, pursuant to CDC 32.100.

F.    Exempt areas.

1.    The Tualatin or Willamette Rivers are regulated by Chapter 28 CDC and are not subject to this chapter. However, wetlands and buffers, regardless of their proximity to these rivers, are subject to this chapter. In areas where there is overlap with Chapter 28 CDC, this chapter shall prevail.

2.    Existing enclosed or piped sections of streams, including any development at right angles to the enclosed or piped sections.

G.    Metro Code Chapter 3.07 Urban Growth Management Functional Plan – Exempt uses and conditioned activities. Where construction of a residence was completed before January 1, 2006, the owners or residents shall not be restricted from engaging in any development that was allowed prior to September 22, 2005; unless such development required obtaining a land use decision, or a building, erosion control, or grading permit. (Ord. 1623 § 1, 2014; Ord. 1647 § 4, 2016)

A.    An application requesting approval for a use or activity regulated by this chapter shall be initiated by the property owner, or the owner’s authorized agent, and shall include an application form and the appropriate deposit or fee as indicated on the master fee schedule.

B.    A pre-application conference shall be a prerequisite to the filing of the application.

C.    The applicant shall submit maps and diagrams at 11 by 17 inches and a written narrative addressing the approval criteria and requirements of this chapter, and any additional copies required by the Planning Director.

D.    Where review of soil maps, Department of Geology and Mineral Industries (DOGAMI) maps, or on-site inspection by the City Engineer reveals evidence of slope failures or that WRA slopes are potentially unstable or prone to failure, geotechnical studies may be required to demonstrate that the proposed development will not cause, or contribute to, slope failure or increased erosion or sedimentation in the WRA or adversely impact surface or modify groundwater flow or hydrologic conditions. These geotechnical studies shall include all necessary measures to avoid or correct the potential hazard.

E.    Applications proposing that streets or utilities cross water resources, or any other development that modifies the water resource, shall present evidence in the form of adopted utility master plans or transportation master plans, or findings from a registered Oregon civil engineer, certified engineering geologist or similarly qualified professional to demonstrate that the development or improvements are consistent with accepted engineering practices.

F.    Site plan. The applicant shall submit a site plan which contains the following information, as applicable:

1.    The name, address, and telephone number of the applicant, the scale (lineal) of the plan, and a north arrow.

2.    Property lines, rights-of-way, easements, etc.

3.    A storm detention and treatment plan and narrative statement pursuant to CDC 92.010(E).

4.    Tables and maps identifying acreage, location and type of development constraints due to site characteristics such as slope, drainage and geologic hazards. For Type I, II, and III lands (refer to definitions in Chapter 02 CDC), the applicant must provide a geologic report, with text, figures and attachments as needed to meet the industry standard of practice, prepared by a certified engineering geologist and/or a geotechnical professional engineer, that includes:

a.    Site characteristics, geologic descriptions and a summary of the site investigation conducted;

b.    Assessment of engineering geological conditions and factors;

c.    Review of the City of West Linn’s Natural Hazard Mitigation Plan and applicability to the site; and

d.    Conclusions and recommendations focused on geologic constraints for the proposed land use or development activity, limitations and potential risks of development, recommendations for mitigation approaches and additional work needed at future development stages including further testing and monitoring.

5.    Boundaries of the WRA, specifically delineating the water resource, and any riparian corridor boundary. If the proposal includes development of a wetland, a wetlands delineation prepared by a professional wetland specialist will be required. The wetland delineation may be required to be accepted or waived through the Department of State Lands (DSL) delineation review process.

6.    Location of existing and proposed development, including all existing and proposed structures, accessory structures, any areas of fill or excavation, water resource crossings, alterations to vegetation, or other alterations to the site’s natural state.

7.    Identify the location and square footage of previously disturbed areas, areas that are to be temporarily disturbed, and area to be permanently disturbed or developed.

8.    When an application proposes development within the WRA, an inventory of vegetation within the WRA, sufficient to categorize the existing condition of the WRA, including:

a.    The type and general quality of ground cover, including the identification of dominant species and any occurrence of non-native, invasive species;

b.    Square footage of ground cover; and

c.    Square footage of tree canopy as measured either through aerial photographs or by determining the tree drip lines. Where only a portion of a WRA is to be disturbed, the tree inventory need only apply to the impacted area. The remaining treed area shall be depicted by outlining the canopy cover.

9.    Locations of all significant trees as defined by the City Arborist.

10.    Identify adopted transportation, utility and other plan documents applicable to this proposal.

11.    For cases processed under CDC 32.110 (hardship), provide the maximum disturbed area (MDA) calculations.

G.    Construction management plan. The applicant shall submit a construction management plan which includes the following:

1.    The location of proposed TDAs (site ingress/egress for construction equipment, areas for storage of material, construction activity areas, grading and trenching, etc.) that will subsequently be restored to original grade and replanted with native vegetation, shall be identified, mapped and enclosed with fencing per subsection (G)(3) of this section.

2.    Appropriate erosion control measures consistent with Clackamas County Erosion Prevention and Sediment Control Planning and Design Manual, rev. 2008, and a tentative schedule of work.

3.    The WRA shall be protected, prior to construction, with an anchored chain link fence (or equivalent approved by the City) at its perimeter that shall remain undisturbed, except as specifically authorized by the approval authority. Additional fencing to delineate approved TDAs may be required. Fencing shall be mapped and identified in the construction management plan and maintained until construction is complete.

H.    Mitigation plan prepared in accordance with the requirements in CDC 32.090.

I.    Re-vegetation plan prepared in accordance with the requirements in CDC 32.100.

J.    The Planning Director may modify the submittal requirements per CDC 99.035.

K.    The following additional requirements apply to applications being submitted under the alternative review process pursuant to CDC 32.070 and 32.080.

1.    Identify the affected WRA and describe the functions it performs (see Table 32-4).

2.    Provide a scaled map that delineates the proposed WRA boundaries determined to be sufficient to sustain the functions occurring at the site and a narrative that justifies the proposal, consistent with CDC 32.080.

3.    Identify the recommended WRA boundary at the site with colored tape, survey markers or other easily identified means for field inspection by staff.

4. Consultant required for alternate review process.

a.    The narrative and analysis required by CDC 32.070 and 32.080 shall be prepared and signed by a qualified natural resource professional, such as a wildlife biologist, botanist, or hydrologist. The Planning Director shall determine the scope of work and specific products required from the consultant. The Planning Director may require a mitigation plan pursuant to CDC 32.090 and/or a re-vegetation plan pursuant to CDC 32.100.

b.    The Planning Director may waive the consultant requirement for simple or minor projects if they determine that it is not necessary in order to satisfy the requirements of this chapter. (Ord. 1623 § 1, 2014; Ord. 1662 § 6, 2017)

No application for development on property containing a WRA shall be approved unless the approval authority finds that the proposed development is consistent with the following approval criteria, or can satisfy the criteria by conditions of approval:

A.    WRA protection/minimizing impacts.

1.    Development shall be conducted in a manner that will avoid or, if avoidance is not possible, minimize adverse impact on WRAs.

2.    Mitigation and re-vegetation of disturbed WRAs shall be completed per CDC 32.090 and 32.100, respectively.

B.    Storm water and storm water facilities.

1.    Proposed developments shall be designed to maintain the existing WRAs and utilize them as the primary method of storm water conveyance through the project site unless:

a.    The surface water management plan calls for alternate configurations (culverts, piping, etc.); or

b.    Under CDC 32.070, the applicant demonstrates that the relocation of the water resource will not adversely impact the function of the WRA including, but not limited to, circumstances where the WRA is poorly defined or not clearly channelized.

Re-vegetation, enhancement and/or mitigation of the re-aligned water resource shall be required as applicable.

2.    Public and private storm water detention, storm water treatment facilities and storm water outfall or energy dissipaters (e.g., rip rap) may encroach into the WRA if:

a.    Accepted engineering practice requires it;

b.    Encroachment on significant trees shall be avoided when possible, and any tree loss shall be consistent with the City’s Tree Technical Manual and mitigated per CDC 32.090;

c.    There shall be no direct outfall into the water resource, and any resulting outfall shall not have an erosive effect on the WRA or diminish the stability of slopes; and

d.    There are no reasonable alternatives available.

A geotechnical report may be required to make the determination regarding slope stability.

3.    Roadside storm water conveyance swales and ditches may be extended within rights-of-way located in a WRA. When possible, they shall be located along the side of the road furthest from the water resource. If the conveyance facility must be located along the side of the road closest to the water resource, it shall be located as close to the road/sidewalk as possible and include habitat friendly design features (treatment train, rain gardens, etc.).

4.    Storm water detention and/or treatment facilities in the WRA shall be designed without permanent perimeter fencing and shall be landscaped with native vegetation.

5.    Access to public storm water detention and/or treatment facilities shall be provided for maintenance purposes. Maintenance driveways shall be constructed to minimum width and use water permeable paving materials. Significant trees, including roots, shall not be disturbed to the degree possible. The encroachment and any tree loss shall be mitigated per CDC 32.090. There shall also be no adverse impacts upon the hydrologic conditions of the site.

6.    Storm detention and treatment and geologic hazards. Per the submittals required by CDC 32.050(F)(3) and 92.010(E), all proposed storm detention and treatment facilities must comply with the standards for the improvement of public and private drainage systems located in the West Linn Public Works Design Standards, there will be no adverse off-site impacts caused by the development (including impacts from increased intensity of runoff downstream or constrictions causing ponding upstream), and the applicant must provide sufficient factual data to support the conclusions of the submitted plan.

C.    Repealed by Ord. 1647.

D.    WRA width. Except for the exemptions in CDC 32.040, applications that are using the alternate review process of CDC 32.070, or as authorized by the approval authority consistent with the provisions of this chapter, all development is prohibited in the WRA as established in Table 32-2 below:

1    The slope is the average slope in the first 50 feet as measured from bankfull stage or OHW.

2    Where the protected water resource is confined by a ravine or gully, the top of slope is the location (30-foot minimum) where the slope breaks to less than 15 percent for at least 50 feet.

3    At least three slope measurements along the water resource, at no more than 100-foot increments, shall be made for each property for which development is proposed. Depending upon topography, the width of the protected corridor may vary.

4    The 50-foot distance may be reduced to 25 feet if a geotechnical study by a licensed engineer or similar accredited professional demonstrates that the slope is stable and not prone to erosion.

Table 32-3

Figure 32-2

Figure 32-3

Figure 32-4

Figure 32-5

Figure 32-6

E.    Per the submittals required by CDC 32.050(F)(4), the applicant must demonstrate that the proposed methods of rendering known or potential hazard sites safe for development, including proposed geotechnical remediation, are feasible and adequate to prevent landslides or other damage to property and safety. The review authority may impose conditions, including limits on type or intensity of land use, which it determines are necessary to mitigate known risks of landslides or property damage.

F.    Roads, driveways and utilities.

1.    New roads, driveways, or utilities shall avoid WRAs unless the applicant demonstrates that no other practical alternative exists. In that case, road design and construction techniques shall minimize impacts and disturbance to the WRA by the following methods:

a.    New roads and utilities crossing riparian habitat areas or streams shall be aligned as close to perpendicular to the channel as possible.

b.    Roads and driveways traversing WRAs shall be of the minimum width possible to comply with applicable road standards and protect public safety. The footprint of grading and site clearing to accommodate the road shall be minimized.

c.    Road and utility crossings shall avoid, where possible:

1)    Salmonid spawning or rearing areas;

2)    Stands of mature conifer trees in riparian areas;

3)    Highly erodible soils;

4)    Landslide prone areas;

5)    Damage to, and fragmentation of, habitat; and

6)    Wetlands identified on the WRA Map.

2.    Crossing of fish bearing streams and riparian corridors shall use bridges or arch-bottomless culverts or the equivalent that provides comparable fish protection, to allow passage of wildlife and fish and to retain the natural stream bed.

3.    New utilities spanning fish bearing stream sections, riparian corridors, and wetlands shall be located on existing roads/bridges, elevated walkways, conduit, or other existing structures or installed underground via tunneling or boring at a depth that avoids tree roots and does not alter the hydrology sustaining the water resource, unless the applicant demonstrates that it is not physically possible or it is cost prohibitive. Bore pits associated with the crossings shall be restored upon project completion. Dry, intermittent streams may be crossed with open cuts during a time period approved by the City and any agency with jurisdiction.

4.    No fill or excavation is allowed within the ordinary high water mark of a water resource, unless all necessary permits are obtained from the City, U.S. Army Corps of Engineers and Oregon Department of State Lands (DSL).

5.     Crossings of fish bearing streams shall be aligned, whenever possible, to serve multiple properties and be designed to accommodate conduit for utility lines. The applicant shall, to the extent legally permissible, work with the City to provide for a street layout and crossing location that will minimize the need for additional stream crossings in the future to serve surrounding properties.

G.    Passive recreation. Low impact or passive outdoor recreation facilities for public use including, but not limited to, multi-use paths and trails, not exempted per CDC 32.040(B)(2), viewing platforms, historical or natural interpretive markers, and benches in the WRA, are subject to the following standards:

1.    Trails shall be constructed using non-hazardous, water permeable materials with a maximum width of four feet or the recommended width under the applicable American Association of State Highway and Transportation Officials (AASHTO) standards for the expected type and use, whichever is greater.

2.    Paved trails are limited to the area within 20 feet of the outer boundary of the WRA, and such trails must comply with the storm water provisions of this chapter.

3.    All trails in the WRA shall be set back from the water resource at least 30 feet except at stream crossing points or at points where the topography forces the trail closer to the water resource.

4.    Trails shall be designed to minimize disturbance to existing vegetation, work with natural contours, avoid the fall line on slopes where possible, avoid areas with evidence of slope failure and ensure that trail runoff does not create channels in the WRA.

5.    Foot bridge crossings shall be kept to a minimum. When the stream bank adjacent to the foot bridge is accessible (e.g., due to limited vegetation or topography), where possible, fences or railings shall be installed from the foot bridge and extend 15 feet beyond the terminus of the foot bridge to discourage trail users and pets from accessing the stream bank, disturbing wildlife and habitat areas, and causing vegetation loss, stream bank erosion and stream turbidity. Bridges shall not be made of continuous impervious materials or be treated with toxic substances that could leach into the WRA.

6.    Interpretive facilities (including viewpoints) shall be at least 10 feet from the top of the water resource’s bankfull flow/OHW or delineated wetland edge and constructed with a fence between users and the resource. Interpretive signs may be installed on footbridges.

H.    Daylighting Piped Streams.

1.    As part of any application, covered or piped stream sections shown on the WRA Map are encouraged to be “daylighted” or opened. Once it is daylighted, the WRA will be limited to 15 feet on either side of the stream. Within that WRA, water quality measures are required which may include a storm water treatment system (e.g., vegetated bioswales), continuous vegetative ground cover (e.g., native grasses) at least 15 feet in width that provides year round efficacy, or a combination thereof.

2.    The re-opened stream does not have to align with the original piped route but may take a different route on the subject property so long as it makes the appropriate upstream and downstream connections and meet the standards of subsections (H)(3) and (4) of this section.

3.    A re-aligned stream must not create WRAs on adjacent properties not owned by the applicant unless the applicant provides a notarized letter signed by the adjacent property owner(s) stating that the encroachment of the WRA is permitted.

4.    The evaluation of proposed alignment and design of the reopened stream shall consider the following factors:

a.    The ability of the reopened stream to safely carry storm drainage through the area without causing significant erosion.

b.    Continuity with natural contours on adjacent properties, slope on site and drainage patterns.

c.    Continuity of adjacent vegetation and habitat values.

d.    The ability of the existing and proposed vegetation to filter sediment and pollutants and enhance water quality.

e.    Provision of water temperature conducive to fish habitat.

5.     Any upstream or downstream WRAs or riparian corridors shall not apply to, or overlap, the daylighted stream channel.

6.    When a stream is daylighted the applicant shall prepare and record a legal document describing the reduced WRA required by subsections (H)(1) and (5) of this section. The document will be signed by a representative of the City and recorded at the applicant’s expense to better ensure long term recognition of the reduced WRA and reduced restrictions for the daylighted stream section.

I.    The following habitat friendly development practices shall be incorporated into the design of any improvements or projects in the WRA to the degree possible:

1.    Restore disturbed soils to original or higher level of porosity to regain infiltration and storm water storage capacity.

2.    Apply a treatment train or series of storm water treatment measures to provide multiple opportunities for storm water treatment and reduce the possibility of system failure.

3.    Incorporate storm water management in road rights-of-way.

4.    Landscape with rain gardens to provide on-lot detention, filtering of rainwater, and groundwater recharge.

5.    Use multi-functional open drainage systems in lieu of conventional curb-and-gutter systems.

6.    Use green roofs for runoff reduction, energy savings, improved air quality, and enhanced aesthetics.

7.    Retain rooftop runoff in a rain barrel for later on-lot use in lawn and garden watering.

8.    Disconnect downspouts from roofs and direct the flow to vegetated infiltration/filtration areas such as rain gardens.

9.    Use pervious paving materials for driveways, parking lots, sidewalks, patios, and walkways.

10.    Reduce sidewalk width to a minimum four feet. Grade the sidewalk so it drains to the front yard of a residential lot or retention area instead of towards the street.

11.    Use shared driveways.

12.    Reduce width of residential streets and driveways, especially at WRA crossings.

13.    Reduce street length, primarily in residential areas, by encouraging clustering.

14.    Reduce cul-de-sac radii and use pervious and/or vegetated islands in center to minimize impervious surfaces.

15.    Use previously developed areas (PDAs) when given an option of developing PDA versus non-PDA land.

16.    Minimize the building, hardscape and disturbance footprint.

17.    Consider multi-story construction over a bigger footprint. (Ord. 1623 § 1, 2014; Ord. 1635 § 19, 2014; Ord. 1647 § 5, 2016; Ord. 1662 § 7, 2017)

This section establishes a review and approval process that applicants can use when there is reason to believe that the width of the WRA prescribed under the standard process (CDC 32.060(D)) is larger than necessary to protect the functions of the water resource at a particular site. It allows a qualified professional to determine what water resources and associated functions (see Table 32-4 below) exist at a site and the WRA width that is needed to maintain those functions. (Ord. 1623 § 1, 2014)

Applications reviewed under the alternate review process shall meet the following approval criteria:

A.    The proposed WRA shall be, at minimum, qualitatively equal, in terms of maintaining the level of functions allowed by the WRA standards of CDC 32.060(D).

B.    If a WRA is already significantly degraded (e.g., native forest and ground cover have been removed or the site dominated by invasive plants, debris, or development), the approval authority may allow a reduced WRA in exchange for mitigation, if:

1.    The proposed reduction in WRA width, coupled with the proposed mitigation, would result in better performance of functions than the standard WRA without such mitigation. The approval authority shall make this determination based on the applicant’s proposed mitigation plan and a comparative analysis of ecological functions under existing and enhanced conditions (see Table 32-4).

2.    The mitigation project shall include all of the following components as applicable. It may also include other forms of enhancement (mitigation) deemed appropriate by the approval authority.

a.    Removal of invasive vegetation.

b.    Planting native, non-invasive plants (at minimum, consistent with CDC 32.100) that provide improved filtration of sediment, excess nutrients, and pollutants. The amount of enhancement (mitigation) shall meet or exceed the standards of CDC 32.090(C).

c.    Providing permanent improvements to the site hydrology that would improve water resource functions.

d.    Substantial improvements to the aquatic and/or terrestrial habitat of the WRA.

C.    Identify and discuss site design and methods of development as they relate to WRA functions.

D.    Address the approval criteria of CDC 32.060, with the exception of CDC 32.060(D).

(Ord. 1623 § 1, 2014)

A    A mitigation plan shall only be required if development is proposed within a WRA (including development of a PDA). (Exempted activities of CDC 32.040 do not require mitigation unless specifically stated. Temporarily disturbed areas, including TDAs associated with exempted activities, do not require mitigation, just grade and soil restoration and re-vegetation.) The mitigation plan shall satisfy all applicable provisions of CDC 32.100, Re-Vegetation Plan Requirements.

B.    Mitigation shall take place in the following locations, according to the following priorities (subsections (B)(1) through (4) of this section):

1.    On-site mitigation by restoring, creating or enhancing WRAs.

2.    Off-site mitigation in the same sub-watershed will be allowed, but only if the applicant has demonstrated that:

a.    It is not practicable to complete mitigation on-site, for example, there is not enough area on-site; and

b.    The mitigation will provide equal or superior ecological function and value.

3.    Off-site mitigation outside the sub-watershed will be allowed, but only if the applicant has demonstrated that:

a.    It is not practicable to complete mitigation on-site, for example, there is not enough area on-site; and

b.    The mitigation will provide equal or superior ecological function and value.

4.    Purchasing mitigation credits though DSL or other acceptable mitigation bank.

C.    Amount of mitigation.

1.    The amount of mitigation shall be based on the square footage of the permanent disturbance area by the application. For every one square foot of non-PDA disturbed area, on-site mitigation shall require one square foot of WRA to be created, enhanced or restored.

2.    For every one square foot of PDA that is disturbed, on-site mitigation shall require one half a square foot of WRA vegetation to be created, enhanced or restored.

3.    For any off-site mitigation, including the use of DSL mitigation credits, the requirement shall be for every one square foot of WRA that is disturbed, two square feet of WRA shall be created, enhanced or restored. The DSL mitigation credits program or mitigation bank shall require a legitimate bid on the cost of on-site mitigation multiplied by two to arrive at the appropriate dollar amount.

D.    The Planning Director may limit or define the scope of the mitigation plan and submittal requirements commensurate with the scale of the disturbance relative to the resource and pursuant to the authority of Chapter 99 CDC. The Planning Director may determine that a consultant is required to complete all or a part of the mitigation plan requirements.

E.    A mitigation plan shall contain the following information:

1.    A list of all responsible parties including, but not limited to, the owner, applicant, contractor, or other persons responsible for work on the development site.

2.    A map showing where the specific adverse impacts will occur and where the mitigation activities will occur.

3.    A re-vegetation plan for the area(s) to be mitigated that meets the standards of CDC 32.100.

4.    An implementation schedule, including timeline for construction, mitigation, mitigation maintenance, monitoring, and reporting. All in-stream work in fish bearing streams shall be done in accordance with the Oregon Department of Fish and Wildlife.

5.    Assurances shall be established to rectify any mitigation actions that are not successful within the first three years. This may include bonding or other surety. (Ord. 1623 § 1, 2014)

A.    In order to achieve the goal of re-establishing forested canopy, native shrub and ground cover and to meet the mitigation requirements of CDC 32.090 and vegetative enhancement of CDC 32.080, tree and vegetation plantings are required according to the following standards:

1.    All trees, shrubs and ground cover to be planted must be native plants selected from the Portland Plant List.

2.    Plant size. Replacement trees must be at least one-half inch in caliper, measured at six inches above the ground level for field grown trees or above the soil line for container grown trees (the one-half inch minimum size may be an average caliper measure, recognizing that trees are not uniformly round), unless they are oak or madrone which may be one gallon size. Shrubs must be in at least a one-gallon container or the equivalent in ball and burlap and must be at least 12 inches in height.

3.    Plant coverage.

a.    Native trees and shrubs are required to be planted at a rate of five trees and 25 shrubs per every 500 square feet of disturbance area (calculated by dividing the number of square feet of disturbance area by 500, and then multiplying that result times five trees and 25 shrubs, and rounding all fractions to the nearest whole number of trees and shrubs; for example, if there will be 330 square feet of disturbance area, then 330 divided by 500 equals 0.66, and 0.66 times five equals 3.3, so three trees must be planted, and 0.66 times 25 equals 16.5, so 17 shrubs must be planted). Bare ground must be planted or seeded with native grasses or herbs. Non-native sterile wheat grass may also be planted or seeded, in equal or lesser proportion to the native grasses or herbs.

b.    Trees shall be planted between eight and 12 feet on center and shrubs shall be planted between four and five feet on center, or clustered in single species groups of no more than four plants, with each cluster planted between eight and 10 feet on center. When planting near existing trees, the dripline of the existing tree shall be the starting point for plant spacing measurements.

4.    Plant diversity. Shrubs must consist of at least two different species. If 10 trees or more are planted, then no more than 50 percent of the trees may be of the same genus.

5.    Invasive vegetation. Invasive non-native or noxious vegetation must be removed within the mitigation area prior to planting.

6.    Tree and shrub survival. A minimum survival rate of 80 percent of the trees and shrubs planted is expected by the third anniversary of the date that the mitigation planting is completed.

7.     Monitoring and reporting. Monitoring of the mitigation site is the ongoing responsibility of the property owner. Plants that die must be replaced in kind.

8.     To enhance survival of tree replacement and plantings, the following practices are required:

a.    Mulching. Mulch new plantings a minimum of three inches in depth and 18 inches in diameter to retain moisture and discourage weed growth.

b.    Irrigation. Water new plantings one inch per week between June 15th to October 15th, for the three years following planting.

c.    Weed control. Remove, or control, non-native or noxious vegetation throughout maintenance period.

d.    Planting season. Plant bare root trees between December 1st and February 28th, and potted plants between October 15th and April 30th.

e.    Wildlife protection. Use plant sleeves or fencing to protect trees and shrubs against wildlife browsing and resulting damage to plants.

B.    When weather or other conditions prohibit planting according to schedule, the applicant shall ensure that disturbed areas are correctly protected with erosion control measures and shall provide the City with funds in the amount of 125 percent of a bid from a recognized landscaper or nursery which will cover the cost of the plant materials, installation and any follow up maintenance. Once the planting conditions are favorable the applicant shall proceed with the plantings and receive the funds back from the City upon completion, or the City will complete the plantings using those funds. (Ord. 1623 § 1, 2014)

The purpose of this section is to ensure that compliance with this chapter does not deprive an owner of reasonable use of land. To avoid such instances, the requirements of this chapter may be reduced. The decision-making authority may impose such conditions as are deemed necessary to limit any adverse impacts that may result from granting relief. The burden shall be on the applicant to demonstrate that the standards of this chapter, including Table 32-2, Required Width of WRA, will deny the applicant “reasonable use” of their property.

A.    The right to obtain a hardship allowance is based on the existence of a lot of record recorded with the County Assessor’s Office on, or before, January 1, 2006. The lot of record may have been, subsequent to that date, modified from its original platted configuration but must meet the minimum lot size and dimensional standards of the base zone.

B.    For lots described in subsection A of this section that are located completely or partially inside the WRA, development is permitted, consistent with this section. The maximum disturbed area (MDA) of the WRA shall be determined on a per lot basis. The MDA shall be the greater of:

1.    Five thousand square feet of the WRA; or

2.    Thirty percent of the total area of the WRA.

C.    The MDA shall be located as follows:

1.    In areas where the development will result in the least square footage encroachment into the WRA.

2.    The applicant shall demonstrate, through site and building design, that the proposed development is the maximum practical distance from the water resource based on the functional needs of the proposed use.

3.    The minimum distance from a water resource shall be 15 feet.

4.    Access driveways shall be the minimum permitted width; select an alignment that is least impactful upon the WRA; and shall share use of the driveway, where possible.

D.    The MDA shall include:

1.    The footprints of all structures, including accessory structures, decks and paved water impermeable surfaces including sidewalks, driveways, parking pads, paths, patios and parking lots, etc. Only 75 percent of water permeable surfaces at grade shall be included in the MDA.

2.    All graded, disturbed or modified areas that are not subsequently restored to their original grade and replanted with native ground cover per an approved plan.

E.    The MDA shall not include:

1.    Temporarily disturbed areas (TDAs) adjacent to an approved structure or development area for the purpose of grading, material storage, construction activity, trenched or buried utilities and other temporary activities so long as these areas are subsequently restored to the original grades and soil permeability, and re-vegetated with native plants per CDC 32.100, such that they are at least equal in functional value to the area prior to the initiation of the permitted activity;

2.    Bay windows and similar cantilevered elements (including decks, etc.) of the principal or secondary structure so long as they do not extend more than five feet towards the WRA from the vertical plane of the house, and have no vertical supports from grade;

3.    PDAs that are not built upon as part of the development proposal will not count in the MDA (e.g., use of an existing access driveway). (Conversely, PDAs that are built upon as part of the development proposal will count in the MDA.);

4.    The installation of public streets and public utilities that are specifically required to meet either the transportation system plan or a utility master plan so long as all trenched public utilities are subsequently restored to the original grades and soil permeability, and revegetated with native plants per CDC 32.100, such that they are at least equal in functional value to the area prior to the initiation of the permitted activity. All areas displaced by streets shall be mitigated for.

Figure 32-7

F.    Development allowed under subsection A of this section may use the following provisions:

1.    Setbacks required by the underlying zoning district may be reduced up to 50 percent where necessary to avoid construction within the WRA, as long as the development would otherwise meet the standards of this chapter. However, front loading garages shall be set back a minimum of 18 feet, while side loading garages shall be set back a minimum of three feet.

2.    Landscaping requirements may be reduced for hardship properties but only if all or part of the WRA is dedicated pursuant to CDC 32.060(C) or if a restrictive deed covenant is established. These reductions shall be permitted outright and, to the extent that the practices are inconsistent with other provisions or standards of the West Linn CDC, this section is given precedence so that no variance is required. The allowable reductions include:

a.    Elimination of landscaping for the parking lot interior.

b.    Elimination of the overall landscape requirement (e.g., 20 percent for commercial uses).

c.    Elimination of landscaping between parking lots and perimeter non-residential properties.

d.    Landscaping between parking lots and the adjacent right-of-way may be reduced to eight feet. This eight-foot-wide landscaped strip may be used for vegetated storm water detention or treatment.

G.    Where a property owner owns multiple platted lots of record where each lot could be built upon under the hardship provisions, the property owner may either use the MDA for each lot on an individual lot by lot basis or may transfer 100 percent of the cumulative MDA of all the lots to those lots that are further away from, or less impactful upon, the WRA. Lot line adjustments may also be used to facilitate the density transfer. See Figure 32-8.

Figure 32-8

H.    Mitigation and re-vegetation of disturbed WRAs shall be completed per CDC 32.090 and 32.100 respectively.

I.    Any further modification of the standards of this chapter or the underlying zone shall require approval of a variance pursuant to Chapter 75 CDC. (Ord. 1623 § 1, 2014; Ord. 1754 § 1 (Exh. A), 2024)

A.    The WRA Map, dated May 2014, is adopted as the official WRA Map. It is intended to identify WRA water features (wetlands, streams, ephemeral streams and riparian corridors). It is not intended to delineate the exact WRA boundaries or water feature alignment. That task will be carried out by staff in the course of site visits where the provisions of Table 32-2 shall apply.

B.    Amendments to the WRA Map may be made in accordance with the provisions of Chapters 98 and 99 CDC. Copies of all map amendments shall be dated with the effective date of the document adopting the map amendment and shall be maintained without change, together with the adopting documents, on file in the Planning Department.

C.    The Planning Director shall maintain in their office, and available for public inspection, an up-to-date copy of the WRA Map. (Ord. 1623 § 1, 2014)