Section 131A. Significant Natural Resources Overlay (SNRO)   (Added by Ord. No. 5269/5-03)

(1) Purpose.   The Significant Natural Resources Overlay (SNRO) District is established for the following purposes:

(a) To provide protection for Significant Natural Resources under Statewide Planning Goal 5 (Natural Resources) and the provisions of the Goal 5 administrative rule (OAR 660, Division 23).   For the purpose of this ordinance, Significant Natural Resources are designated as Significant Wetlands, Riparian Corridors and Wildlife Habitat. These resources have been inventoried within the City of Hillsboro according to procedures, standards and definitions established under Goal 5 and are identified in the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01).

(b) To establish standards to conserve and protect the functions and values of Significant Natural Resources while allowing reasonable economic use of property where adverse impacts to the resources can be mitigated.

(c) To establish standards and procedures for evaluating and permitting developments, alterations and vegetation removal that affects Significant Natural Resources.

(d) To enhance coordination between County, state, federal and other jurisdictional agencies and regional planning efforts, including Clean Water Services, Metro and the Tualatin Basin Goal 5 program, regarding alterations and development activities in or proximate to Significant Natural Resources.

(2) Definitions

(a) Abbreviated Environmental Report.   A report that at a minimum, includes the information specified in Section 7(c)(1), and describes the condition of natural resources on a site and the general location of resource boundaries as indicated through photos showing site conditions and staked areas depicted on a site map including where site alteration or structures are proposed, and analyzes the impact of Development on Significant Natural Resources.   It also demonstrates how the proposed Development can be carried out on the site in conformance with applicable standards for Development in SNR Sites and Impact Areas.  

(b) Break in Slope.   The transition point where a valley or river bank slope flattens and represents an historic geologic terrace of a stream or river.   The point at which the grade extending from a break in slope, away from the stream or river, is less than 25%.   Break in slope is also commonly referred to as top of ravine in steeply sloped headwater environments.   Break in slope does not include minor surface anomalies that result from localized landslide slumps or site grading.

(c) Creation (of a natural resource).   Creation begins with a non-wetland, riparian or wildlife habitat ecosystem and attempts to modify the vegetation, hydrology and/or topography in order to create the desired conditions. Modification of the soils and vegetation may be included in a creation design in order to facilitate the transition to a natural resource system. The goal of creation projects is to produce a functional wetland, riparian area, or wildlife habitat.

(d) Dangerous Tree.   Any tree which, in the opinion of an expert approved by the City of Hillsboro (such as, but not limited to, an arborist, a professional forester or landscape architect), has a strong likelihood of causing a hazard to life or property.

(e) Delineation.   An analysis of a resource by a Qualified Natural Resources Professional that determines its boundary.   Wetland boundaries shall be delineated using methods described in the 1987 US Army Corps of Engineers Wetlands Delineation Manual or using methods currently accepted by the Oregon Division of State Lands and US Army Corps of Engineers. Riparian and wildlife habitat boundaries shall be based on an assessment of the tree canopy and plant communities described for the resource in the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01) .

(f) Development.   All human-induced changes to improved or unimproved real property including:

(1) Construction of new structures which increase the building footprint on the real property;

(2) Redevelopment;

(3) Change to existing lot boundaries including, but not limited to, subdivisions and minor partitions;

(4) Site alterations resulting from clearing, grading, filling, excavating, dredging, surface mining;

(5) Paving;

(6) Construction of earthen berms and retaining walls; and

(7) Vegetation removal.

"Development" does not include:

(8) Farming activities when conducted in accordance with accepted farming practices as defined in ORS 30.930, ORS 568.900 or any successor laws; and

(9) Construction on lots in subdivisions meeting the criteria of ORS 92.040(2) or any successor law.

(g) Enhancement.   Modification of a SNR Site to improve its resource functions and values or modification of an Impact Area to improve its ability to buffer the adjacent resource from the adverse impacts associated with Development.  

(h) Environmental Report.   A report that at a minimum, includes the information specified in Section 7 (c)(2), and describes the condition of natural resources on a site and specific resource boundaries, and analyzes the impacts of Development on Significant Natural Resources. It also outlines measures to prevent negative impacts and provides mitigation and enhancement plans.

(i) Excavation.   Removal of earth or mineral matter by human action.

(j) Fill.   Deposition of material by human action.

(k) Grading.   The cutting and/or filling of the land surface to a desired slope or elevation.

(l) Impact Area.   The impact area is within the boundaries of the SNRO District and represents the area in which allowed uses could "adversely affect" the identified resource.   The impact areas as depicted on the Significant Natural Resources Overlay District Map consist of the following:

* Measured from the edge of the delineated wetland boundary.

** Measured from the edge of the tree canopy for the protection of the root-zone .

(m) Isolated Upland Wildlife Habitat.   Areas of Significant Wildlife Habitat identified in the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01) , which are not contiguous to a stream, wetland or riparian corridor.

(n) Local Wetlands Inventory.   A systematic survey of an area by a jurisdiction to identify, classify and map the approximate boundaries of wetlands in accordance with the requirements of OAR 141-086-0180, that is used in place of the National Wetlands Inventory and is incorporated into the Statewide Wetlands Inventory once approved by the Oregon Division of State Lands.

(o) Mitigation.   A means of compensating for impacts to a Significant Natural Resource or its Impact Area including Replacement, Creation, or Enhancement activities.   Some examples of mitigation actions are construction of new wetlands to replace an existing wetland that has been filled, replanting trees, removal of nuisance plants, and restoring streamside vegetation where it is disturbed.

(p) Native Vegetation.   Plants identified as naturally occurring and historically found within the City of Hillsboro , as listed on Metro's Native Plant List.

(q) Nuisance Plants.   Invasive non-native plants listed on Metro's Nuisance Plant List.

(r) Permanent Open Space.   Land within a development which will be protected from development in perpetuity through the use of a conservation easement, dedication or other similar means.

(s) Planning Commission.   The planning commission of the City of Hillsboro .

(t) Planning Director.   The planning director of the City of Hillsboro or the director's designee.

(u) Practicable.   Capable of being put into practice or of being done or accomplished given consideration of available technology and project economics relative to the potential adverse impacts on the functions and values of the SNR as described in the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01), the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro, and the City of Hillsboro Economic, Social, Environmental and Energy Consequences Analyses Report .

(v) Qualified Natural Resources Professional.   An individual who has appropriate credentials verifying proven expertise and vocational experience in a given natural resource field.

(w) Redevelopment.   Redevelopment includes but is not limited to: the expansion of or change to an existing building footprint or structure; reconfiguration of existing roadways, driveways or parking lots; and land disturbing activities related to structural or impervious area modifications.   Redevelopment does not include measures to repair, maintain or remove existing structures, roadways, driveways, accessory uses, or other development provided they are consistent with existing City regulations and do not encroach further into the Significant Natural Resource Site.   Redevelopment also does not include interior improvements and vertical additions (additional stories) that do not modify the existing building footprint including associated impervious area or replacement of a structure(s) lost due to a catastrophic event such as fire.

(x) Repair and Maintenance.   Activities intended to preserve and care for a structure, landscaping, or other improvements (including the continued maintenance of adjacent native vegetation for prevention of fire hazard) to such an extent that they remain safe, presentable and carry out the purpose for which they were initiated, installed, constructed or required, without expanding the existing development or activity.

(y) Replacement.   The substitution of newly created resource area through the construction of a resource on a site that is no longer a significant resource and is not within an SNR Site.   In the case of wetland creation, this can be done only on a site where conditions exist that can produce and sustain a wetland.

(z) Review Authority.   The person or body responsible for making a decision regarding an application or appeal.   The City of Hillsboro Planning Commission is the review authority for Type 2 Significant Natural Resources Permits and the City of Planning Director or the director's designee is the review authority for Type 1 Significant Natural Resources Permits.

(aa) Riparian Area.   The area adjacent to a river, lake, or stream, consisting of the area of transition from an aquatic ecosystem to a terrestrial ecosystem as defined in the Goal 5 rule (OAR 660-023-0090).

(bb) Riparian Corridor.   A Goal 5 resource that includes the water areas, fish habitat, adjacent riparian areas, and wetlands within the riparian area boundary as defined in the Goal 5 rule (OAR 660-023-0090).   

(cc) Riparian Upland Resources.   Areas which include a combination of significant wildlife habitat and riparian resources, as identified in the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01), which are contiguous to a stream or wetland.

(dd) Significant Natural Resources (SNR). Significant Wetlands, Riparian Corridors and Wildlife Habitat within the City of Hillsboro city limits and identified in the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01).

(ee) Significant Natural Resources Permit (SNRP).   A Significant Natural Resources Permit is a permit granted by the Review Authority after a review process is completed that allows certain activities or uses listed in the Activities/Uses Table to occur in the Significant Natural Resources Overlay District.  

(ff) Significant Natural Resources (SNR) Site.   The area where Significant Natural Resources are located.

(gg) Vegetation Removal. The removal of vegetation through cutting, clearing, grubbing, mowing, and similar activities.

(hh) Wetlands. Areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that, under normal circumstances, do support a prevalence of vegetation typically adapted for life in saturated soil conditions.

1. A "Significant Wetland" is a wetland that meets the Division of State Lands definition of a Locally Significant Wetland and is on the City of Hillsboro 's Local Wetlands Inventory.   Significant wetlands may be "associated" with a stream or hydrologically "isolated".

2. A "Non-Significant Wetland" is a wetland that does not meet the Division of State Lands definition of a Locally Significant Wetland and does not appear on the City of Hillsboro 's Local Wetlands Inventory. Non-significant wetlands are not regulated by this chapter, but do require DSL notification under ORS 227.350.

(ii) Wildlife Habitat.   An area upon which wildlife depend in order to meet the requirements for food, water, shelter, and reproduction as defined in the Goal 5 rule (OAR 660-023-0110).

(3) Establishment of Significant Natural Resources Overlay (SNRO) District

a) A Significant Natural Resources Overlay District is hereby created as a superimposed zone applied over existing zones, the boundaries of which encompass all Significant Natural Resource Sites and Impact Areas as depicted on the Significant Natural Resources Overlay District Map.

b) Applicability. Properties containing Significant Natural Resource Sites and Impact Areas shall be subject to the requirements of this chapter.  

(1) The standards and procedures of this chapter:

(a) Apply to all Development proposed on land located within the SNRO District except as noted in 131A(3)(a)(2);

 

(b) Are in addition to the standards of the underlying zone and these requirements shall be in addition to any other development review criteria required by Zoning Ordinance No. 1945, as amended; and

 

(c) In cases of conflict, the standards of this chapter apply.

(2) Exception.   On each legal lot of record existing at the time of the adoption of this ordinance, Development up to a maximum of 200 square feet within a five (5) year period is exempt from these requirements.

(3) Properties annexed to the City generally fall into two categories regarding verification of the presence of Significant Natural Resources:

(a) Properties previously identified as containing Significant Natural Resources as depicted and described in the adopted City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01), whereby the SNR Site and Impact Area will be included in the SNRO District as part of the rezoning process.

(b) Properties not previously inventoried by the City that contain natural resources shall be inventoried and a significance determination made using the methodologies described in the adopted City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01).   Natural resources determined to be significant and their Impact Areas shall be added to the SNRO District as part of the rezoning process.   An Economic, Social, Environmental and Energy (ESEE) Consequences Analysis shall be conducted for SNR Sites added to the SNRO District using the methodology described in the adopted City of Hillsboro Economic, Social, Environmental and Energy Consequences Analyses Report to determine the SNRO type of protected area that will apply to the site (e.g., Impact Area, Level 1, Level 2, and/or Level 3).

c) Mapping .   The SNRO District is an overlay district which is based upon the Significant Wetlands, Riparian Corridors, Wildlife Habitat areas and Impact Areas as identified in the adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resources Inventory and Assessment Report (Ord. No. 5066/9-01) and Economic, Social, Environmental and Energy (ESEE) analyses, completed pursuant to the Goal 5 and Oregon Administrative Rules 660, Division 23 provisions.  

Within the SNRO District there are four types of protected areas:

1. Impact Areas

2. Resource Level 1: Moderately Limit

3. Resource Level 2: Limit

4. Resource Level 3: Strictly Limit

The Significant Natural Resources Overlay District Map generally identifies the extent and location of the Significant Natural Resource Sites and their Impact Areas.   The applicant shall be responsible for surveying and mapping the precise location of the SNR Site and Impact Area on the property at the time of application submittal.   Where a delineation of the resource boundary determines that the SNR Site or Impact Area is no longer present, that portion of the property shall not be subject to these provisions.

The Significant Natural Resources Overlay District Map is adopted and incorporated into this ordinance as though fully set forth.   The Planning Director shall maintain a reproducible copy of the Map showing all amendments.   The Planning Director is delegated authority to amend the Significant Natural Resources Overlay District Map to reflect changes to SNR Site boundaries based on new boundary or resource level information obtained as part of site specific studies, annexations to the City and other changes allowed by this ordinance.

(4) Coordination Among Regulatory Agencies

The regulations of other agencies may apply to development proposals on lands containing natural resources. These agencies include the U.S. Army Corps of Engineers, the Oregon Division of State Lands, the U.S. Fish and Wildlife Service, the Environmental Protection Agency, the Oregon Department of Fish and Wildlife, Washington County, and Clean Water Services (CWS).

 

The City will notify applicable agencies for referral responses to specific development proposals prior to the issuance of City permits. The City shall also encourage the applicant to contact applicable agencies before development plans are completed so as to consider the requirements and restrictions that may be imposed by the agencies, including CWS.  

 

CWS requires that applicants secure a service provider letter from the District or its designee, which specifies the conditions and requirements associated with Vegetated Corridors and Sensitive Areas necessary for the District to issue a Stormwater Connection Permit pursuant to the CWS Design and Construction Manual.

(5) Activities and Uses Permitted Outright, Requiring Significant Natural Resources Permit or Prohibited in the Significant Natural Resources Overlay District

a) Permitted Uses .   Uses designated as "Permitted" in the table below shall be allowed in the SNRO District to the extent that they are not prohibited by the provisions of any underlying zone or any applicable conditions of approval.   Permitted uses shall be in compliance with applicable Federal, State and local requirements.

b) Uses Requiring a Significant Natural Resources Permit .   Uses designated as "SNRP 1a" "SNRP1b" or "SNRP 2" in the table below may be permitted upon the issuance of a Significant Natural Resources Permit (SNRP) pursuant to Section 131A(6).  

 

There are two types of Significant Natural Resources Permits, Type 1 and Type 2.  

1. A Type 1 SNRP is an administrative permit whereby the Review Authority is the Planning Director.   To distinguish between activities and uses where Development is proposed that may have a greater impact to the SNR and additional public notification is needed, Type 1 Significant Natural Resources Permits are divided into SNRP 1a and SNRP 1b, as follows:

(a) SNRP 1a.  Applies when Development greater than five hundred (500) square feet is proposed in Impact Areas, and when less than five hundred (500) square feet of Development is proposed in Level 1 and Level 2 SNR Sites.  Notice of a SNRP 1b application shall be provided by sending notices by mail not less than 10 days prior to the date of decision to owners of property situated within a 200 foot radius of the boundary of the property subject to the request, using for this purpose the name and address of the owners as shown upon the current records of the County Assessor.  Failure of a person to receive the notice specified in this Section shall not invalidate any proceeding in connection with the application for a Significant Natural Resource Permit.  (Amended by Ord. No. 5778/8-07.)

(b) SNRP 1b.  Applies when development greater than five hundred (500) square feet is proposed in Level 1 or Level 2 SNR Sites or less than five hundred (500) square feet of development is proposed in Level 3 SNR Sites.  Notice of a SNRP 1b application shall be provided by sending notices by mail not less than 10 days prior to the date of decision to owners of property situated within a 200 foot radius of the boundary of the property subject to the request, using for this purpose the name and address of the owners as shown upon the current records of the County Assessor. Failure of a person to receive the notice specified in this Section shall not invalidate any proceeding in connection with the application for a Significant Natural Resource Permit.  (Amended by Ord. No. 5778/8-07.)

2. A Type 2 SNRP is a quasi-judicial permit whereby the Review Authority is the Planning Commission.   Decisions regarding SNRP 2 applications for activities or uses within the SNRO District shall be rendered by the Planning Commission after completion of the review process.   The procedure for permitting these uses shall be the same as provided for in Sections 78 - 82, except that the matter will be heard before the Planning Commission.

c) Prohibited Uses.  Uses designated as "Prohibited" in the table below shall not be allowed in the SNRO District.

d) Activities not listed below.   All other activities are prohibited in the SNRO District unless found by the review authority to be similar to a use allowed in the SNRO District pursuant to Section 89. 

[1] Up to a maximum of 500 square feet within a five (5) year period.

(6) Procedures for Significant Natural Resources Permit (SNRP)

a) Pre-Application Conference and Review.   When a review of development affected by the SNRO District is required, a Pre-Application review shall be held before submittal of a SNRP 1b or SNRP 2 application.

b) Completeness Check.   Staff will review the application to verify that all required materials have been submitted.

c) Agency Notice.   If applicable, staff must send a Wetland Land Use Notification Form to the Division of State Lands declaring acceptance of a complete application for activities that are wholly or partially within area identified as wetlands on the Statewide Wetlands Inventory as required by ORS 227.350.

d) Decisions.  Decisions regarding SNRP applications shall be made by the appropriate Review Authority.

1. Decisions regarding SNRP 1a or SRNP 1b applications for activities or uses within the SNRO District shall be rendered by the Planning Director after completion of the review process.

(a) SNRP 1a.   Notice of a decision regarding SNRP1a application shall be mailed to the applicant and the applicant's representative.

(b) SNRP 1b.   Notice of a SNRP 1b application shall be provided by sending notices by mail not less than 10 days prior to the date of decision to adjacent property owners located generally within the area enclosed by lines parallel to and 100 feet from the exterior boundaries of the property involved, using for this purpose the name and address of the owners as shown upon the current records of the County Assessor.   Failure of a person to receive the notice specified in this section shall not invalidate any proceedings in connection with the application for a SNRP.

2. Decisions regarding SNRP 2 applications for activities or uses within the SNRO District shall be rendered by the Planning Commission after completion of the review process.   The procedure for permitting these uses shall be the same as provided for in Sections 78 - 82, except that the matter will be heard before the Planning Commission .

e) Appeal.   Appeals shall be subject to the provisions set forth in Sections 117 through 119.  

(7) Materials for SNRP Applications

The applicant shall submit the following materials in order to allow the consideration and decision of allowing proposed activities or uses on properties meeting the criteria outlined in Section 131A (3).

a) A completed application on a form prescribed by the City, with the appropriate fee;

b) Other information found necessary by the applicant to show that the standards as listed in Section 131A (8) will be met.

c) An environmental assessment consisting of either an Abbreviated Environmental Report or an Environmental Report shall be prepared and submitted by the applicant when it appears that any portion of a proposed development activity will occur within property designated "SNRO District " on the City of Hillsboro Significant Natural Resources Overlay District Map , unless the Planning Director finds, based on the location of the boundary of the Significant Natural Resource (SNR) Site, that none of the proposed development activity will take place within the SNR Site or its Impact Area, in which case the environmental assessment need not be prepared.   Activities and uses requiring a SNRP 1a, or projects proposing to disturb less than 500 square feet of area within the boundaries of the SNRO District shall prepare an Abbreviated Environmental Report.   Activities and uses requiring a SNRP 1b or SNRP 2 and proposing to disturb 500 square feet or more of area within the boundaries of the SNRO District shall prepare an Environmental Report.

1. Abbreviated Environmental Report.  Areas where structures are proposed to be located or vegetation is proposed to be removed shall be staked, indicated on the site map and photos taken of those areas.   The Abbreviated Environmental Report shall:

(a) Include a site map drawn to scale showing the location of:

(i) All existing and proposed locations of all property lines, structures, streets, driveways, and off-street parking and loading facilities;

(ii) Trees (type, species and diameter) and vegetation;

(iii) Where photos were taken and which direction the applicant was facing;

(iv) Where stakes were placed;

(v) Areas where vegetation is proposed to be removed; and  

(vi) Topography (2-foot contour interval).

(b) Include photos showing site conditions including but not limited to existing vegetation and staked areas where structures are proposed.

(c) Address the impacts of the proposed development on the SNR Site and its Impact Area. This assessment shall take into account features and characteristics of the site as identified in the Local Wetlands Inventory and adopted List of Significant Goal 5 Natural Resource Sites in Hillsboro and the City of Hillsboro Goal 5 Natural Resources Inventory and Assessment Report (Ord. No. 5066/9-01).

(d) Demonstrate how the proposed development can be carried out on the site in conformance with applicable standards for development in SNR Sites and Impact Areas.

2. Environmental Report.   If required, the Environmental Report shall include all submittal requirements of the Abbreviated Environmental Report and the following additional requirements:

(a) Be prepared by one or more Qualified Natural Resources Professionals.

(b) Include the results of a delineation of each of the resources present on the site (Wetland, Riparian Corridor, Upland Wildlife Habitat) and the conditions of topography, soils and vegetation found on the site.

(c) The site map shall also show the location of pedestrian walkways, landscaped areas, utilities and easements. The delineated location of Significant Natural Resources and the boundaries of the Significant Natural Resources Overlay designation shall also be required. A cross-sectional view of the proposed use may be required to show slopes and other pertinent information.

(d) Make recommendations concerning the nature and extent of site alterations and improvements to take place on the site in connection with the proposed development in order to reduce negative impacts to the maximum feasible extent.

3. The Planning Director may authorize the use of alternative means of establishing the location of Impact Area boundaries where the applicant does not have access to the Significant Natural Resource and therefore cannot conduct a delineation.

4. The Planning Director may consult with a professional with appropriate expertise to evaluate an applicant's Abbreviated Environmental Report or Environmental Report prepared under this Section, or may rely on appropriate staff expertise, in order to properly evaluate the report's conclusions.

5. The Planning Director shall determine the adequacy of the Abbreviated Environmental Report or Environmental Report and may reject such reports as found to be deficient in addressing the requirements as stated above.   Such rejection shall be grounds for denial of a development permit application for development involving an SNR Site or its Impact Area.  

(8) Standards Governing SNRP Approvals in the SNRO District

The Review Authority may grant approval of any of the development actions listed in Section 131A (5) as requiring a "SNRP", only if the Review Authority makes findings that all of the following requirements have been satisfied:

a) Activities and Development in Impact Areas .      

1. To the extent practicable, proposed activities and Development shall be located and designed to minimize potential adverse impacts to SNR functions and values.   Efforts to minimize adverse impacts may include, but are not limited to:   locating the Development away from the SNR Site, avoiding the root zone of trees within the adjacent SNR Site, buffering the SNR Site with additional native landscaping and reducing effective impervious surfaces within the Development.

2. Where it can be demonstrated through the SNRP process that the proposed activity or Development within the Impact Area will have no adverse impact on the SNR Site, no compensatory mitigation is required.   All other adverse impacts resulting from regulated activities and Development within the Impact Area shall be mitigated pursuant to Section 131A (11).

b) Activities and Development within Significant Natural Resource Sites .  

1. Within Level 1 SNR Sites, activities and Development shall be located and designed to minimize potential adverse impacts to the SNR Site to the extent practicable.

2. Within Level 2 SNR Sites, activities and Development shall be located and designed to avoid potential adverse impacts to the SNR Site to the extent practicable.

3. Within Level 3 SNR Sites, activities and Development shall be avoided altogether to the extent practicable.

4. When Development within an SNR Site cannot be avoided, the proposed Development will be located and designed to minimize potential adverse impacts to SNR functions and values as identified in the City of Hillsboro Goal 5 Natural Resource Inventory and Assessment Report (Ord. No. 5066/9-01).

5. All Development within SNR Sites shall be mitigated pursuant to Section 131A (11).

c) Utilities, Streets and Stormwater Management.

1. In instances where a designated   location or alignment is specified in an adopted facilities plan, such facilities may be placed in such specified areas and their location shall not be subject to the standards and procedures of the SNRO District, except for mitigation pursuant to Section 131A(11).   In all other instances of public or private utility location, when it is shown to the satisfaction of the Review Authority that there is no other practicable alternative location, public and private utilities may be placed within a SNR Site. If a utility is allowed within the Significant Natural Resource, mitigation shall be required pursuant to Section 131A (11).

2. In instances where a designated location or alignment of public streets, driveways or accesses is specified in an adopted transportation plan, such facilities may be located in accordance with such plans and shall not be subject to the standards or procedures of the SNRO District, except for mitigation pursuant to Section 131A(11).   In all other instances, public or private streets or driveways may be placed through a SNR Site to access buildable areas of the property if it is shown to the satisfaction of the Review Authority that there is no other practicable method of access. If allowed, the applicant shall comply with the following requirements:

(a) Demonstrate to the Review Authority that there is no other practicable location within the project boundaries or off-site through the use of easements.

(b) Design rights-of-way, roadways, driveways and pathways to be the minimum width necessary within the SNR Site while also allowing for safe passage of vehicles, bicycles and/or pedestrians.

(c) Use bridges, arched culverts, or box culverts with a natural bottom for crossing of a SNR Site if the crossing is found unavoidable. The number of crossings shall be minimized through use of shared access for abutting lots and access through easements for adjacent lots.

(d) Plan for future extensions of shared access, access easements or private streets to access potential new building sites in order to avoid encroachments into the SNR Site.

(e) Mitigate for loss of any portion of the SNR Site pursuant to Section 131A (11).

3. Development using methods other than specified above within a SNR Site may only be allowed when the applicant can demonstrate that there is a public need for the proposed development and the public benefit to be derived from the development outweighs adverse impacts on the SNR Site resulting from the proposal.

(9) Development Standards

(a) All Development within the SNRO District shall be subject to the following development standards:

1. Significant Natural Resource and Impact Area boundaries shall be surveyed staked and demarcated with standard orange construction fencing or equivalent by a Qualified Natural Resources Professional prior to any construction, demolition, grading, or site clearing.

2. Protective measures and erosion control measures shall comply with the City's adopted erosion control standards (Ord. No. 4981-12/00). These measures shall remain in place until the final site inspection is completed.

3. During construction there shall be no stockpiling of fill materials, parking, or storage of construction equipment except for staging activities for allowed construction projects that occur within the permitted work window within a Significant Natural Resource or its Impact Area unless no other practicable alternatives are available.

4. The types, sizes, and intensities of lights must be placed so that they do not shine directly into the Significant Natural Resource.

5. Plantings within the Significant Natural Resources shall only be with species on the Native Plant List.

6. Plantings within the Impact Area shall not include species which are identified as Nuisance Plants.

7. No herbicides or pesticides shall be used in a Significant Natural Resource or its Impact Area except as applied by a licensed applicator in accordance with a pesticide management plan for control of nuisance plants as identified in the Nuisance Plant List or to eradicate pests or diseases affecting Native Vegetation.

(b) The standards above are in addition to all construction requirements imposed as conditions of approval by the City of Hillsboro or other permitting agencies provided that the area within the SNRO District may be used to satisfy the open space and landscape requirements of Sections 127(III)(H) and 133(V)(A)(1).

(10)  Adjustments from Standards of Underlying Zoning

In order to further the purposes of the SNRO District, the Review Authority may allow adjustments from the minimum and maximum structural setbacks and minimum and maximum lot coverage standards of the underlying zone, provided consideration is given to potential impacts to neighboring properties.

(11)  Compensatory Mitigation Standards

When potential adverse impacts to a Significant Natural Resource or its Impact Area   cannot be avoided, compensatory mitigation pursuant to this section is required.

(a) When mitigation for potential adverse impacts to a SNR Site is also required by Oregon Division of State Lands, U.S. Army Corps of Engineers and/or Clean Water Services, a copy of the mitigation plan prepared in compliance with the requirements of the regulating agency(ies) shall be submitted to the Review Authority.   The City shall not issue a building permit until all applicable Regional, State and Federal permit approvals have been granted.

(b) When mitigation for potential adverse impacts to areas within the SNRO District, which are not otherwise regulated by the Oregon Division of State Lands, U.S. Army Corps of Engineers or Clean Water Services, is required by this chapter, a mitigation plan prepared by a Qualified Natural Resources Professional shall be submitted to the Review Authority.

1. The mitigation plan shall document the location of the impact to the Significant Natural Resource or Impact Area, the existing conditions of the Significant Natural Resource or Impact Area prior to impact, the location of the proposed mitigation area, a detailed planting plan of the proposed mitigation area with species and density, and a narrative describing how the adverse impacts will be mitigated.

2. Minimum compensatory mitigation ratios shall be as follows:

For example, a proposed development which would impact 600 square feet within a Level 3 Resource and 1,200 square feet of Impact Area would be required to provide mitigation as follows:

• For the Level 3 resource, either replacement of 900 square feet or enhancement of 1,800 square feet (or a combination of the two);

• For the Impact Area, enhancement of 1,200 square feet.

3. Proposed mitigation shall meet the following criteria:

(a) Mitigation shall occur on-site and as close to the Impact Area as possible. If this is not feasible, mitigation shall occur within the Urban Growth Boundary of Hillsboro.

(b) All vegetation planted within the mitigation area shall be from the Native Plant List.   Species to be planted in the mitigation area shall replace those impacted by the development activity.

(c) No plants on the Nuisance Plant list are to be planted within the mitigation area.

 

(d) Trees shall be planted at a density of not less than 5 per 1,000 square feet. Shrubs shall be planted at a density of not less than 10 per 1,000 square feet.

(e) The revegetation standards in Clean Water Services "Design and Construction Standards for Sanitary Sewer and Surface Water Management, Appendix D, Landscape Design Requirements" provide a guideline for proposed mitigation.

(12) Natural Resource Enhancement

Resource enhancement projects such as bank stabilization, riparian enhancement, in-channel habitat improvements, and similar projects which propose to improve or maintain the quality of a Significant Natural Resource or its Impact Area shall be approved if the applicant demonstrates that all of the following are met:

a) There will be improvement in the quality of at least one ecological function or value of the resource; and

b) Only species listed in the Native Plants List shall be planted.

For the purpose of this section, a "resource enhancement project" does not include required mitigation pursuant to Section 131A(11).

(13) Natural Resource Management Plan

a) Purpose.  Airports and other public transportation facilities may require regulatory flexibility in addressing natural resource management issues in order to protect public health and safety. Pursuant to an approved Natural Resource Management Plan, future development within a Natural Resource Management Plan area   (plan area) may vary from the following SNRO District requirements:

1. Standards Governing SNRP Approvals in the SNRO District (Section 131A(8)),

2. Development Standards (Section 131A(9)), and

3. Compensatory Mitigation Standards (Section 131A(11))

b) Applicability.   Public agencies responsible for transportation facilities may prepare and submit Natural Resource Management Plan applications for consideration by the Planning Commission.

c) Decisions.   Decisions regarding Natural Resource Management Plan applications shall be rendered by the Planning Commission after completion of the review process.   The procedure for permitting these uses shall be the same as provided for in Sections 78 - 82, except that the matter will be heard before the Planning Commission .

d) Submittal Requirements.   An application for a Natural Resource Management Plan shall include all of the submittal requirements for a SNRP2 including an Environmental Report pursuant to 131A(7)(c)(2).

e) Standards.   Standards governing Natural Resource Management Plan Approvals in the SNRO District.   The Planning Commission may grant approval of a Natural Resource Management Plan, only if the Planning Commission makes the following findings:

1. The proposed Natural Resource Management Plan substantially conforms to the purpose and intent of the SNRO District; and

2. The proposed Natural Resource Management Plan will result in an overall improvement in the functions and values of the natural resources within the plan area.

(14) Residential Land Divisions. When a lot which includes a SNR Site is the subject of a land division application the following provisions apply:

a) Adjustments to the following standards may be approved during the SNRP process to allow development consistent with the purposes of the SNRO District provided consideration is given to the potential impacts on neighboring properties:

1. Minimum required lot width and depth;

2. Minimum required density; and

3. Minimum lot size.  Residential lot sizes may be averaged to allow lots less than the minimum lot area required by the underlying zone, as long as the average area for all lots is not less than required by underlying zone.  No lot created under this provision shall be less than 75% of the minimum lot size required in the underlying zone. (Amended by Ord. No. 5778/8-07.)

b) Where a proposed land division would create twelve (12) or more lots and 50% or more of the site is within the SNRO District:

1. The development proposal shall be reviewed as a Planned Unit Development pursuant to Section 127.

2. In cases where the SNRO District is applied to otherwise developable land, residential density within the SNRO District shall be no greater than 50% of the maximum permitted by the underlying zoning district. The surplus density may be transferred to developable portions of a lot.   However, density transfers shall be limited by the Review Authority such that not more than 30% of the maximum density otherwise allowed in the SNRO area is eligible to be transferred to the non-SNRO area.   This transfer is intended to allow densities equivalent to 80% of the maximum allowed in the SNRO to be developed elsewhere on the site.

c) The final plat shall show Significant Natural Resources and their associated Impact Areas to be designated as open space as either a conservation easement or a separate permanent open space tract.   Responsibility for maintenance and preservation of such conservation easements or such permanent open space tracts, consistent with Sections 131A (8), (9), (11) and (12), shall be specified in covenants, conditions and restrictions or other legal instrument subject to approval by the Planning Director and recorded prior to approval of the final development plan.

(15)  Preservation of SNR in Additional Open Space. At the option of the developer, Significant Natural Resource Area in excess of the requirements for usable open space, which is set aside for that purpose, may be subtracted from the net residential area of the development for density calculation.  Additional open space so set aside shall be identified on the final plat (or final development plan if no land division is involved) as a conservation easement of a separate permanent open space tract, with responsibility for maintenance specified as required in Section 131A (14).  (Amended by Ord. No. 5333/1-04 and 5778/8-07.)

(16)  Modification of Significant Natural Resources or Impact Area Boundaries.
The boundaries or level of a Significant Natural Resources or its Impact Area may be modified as part of the development review process identified in Section 131A(6) to reflect new boundary or level information obtained as part of the site-specific studies or to include new mitigation areas proposed as part of the development. Modifications to boundaries of Significant Natural Resources that are locally significant wetlands shall require review and approval by the Division of State Lands. (Amended by Ord. No. 5333/1-04)

 

(Section 131A added by Ord. No. 5269/5-03)