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1. General.

1.1. Findings. The town finds that critical areas’ biological and physical functions benefit the town by protecting water quality, providing fish and wildlife habitat, supporting the food chain, storing and conveying floodwaters, recharging ground water, controlling erosion, and providing aesthetic values and recreation.

1.2. Purpose. The purpose of this critical areas code is to:

A. Protect the functions and values of ecologically sensitive areas while allowing for reasonable use of private property, through the application of the best available science.

B. Ensure no net loss of shoreline ecological functions by regulating and protecting critical areas within shoreline jurisdiction.

C. Implement the Growth Management Act and the goals of the comprehensive plan, and

D. Protect the public from injury and loss due to slope failures, erosion, seismic events, volcanic eruptions, or flooding.

1.3. Definitions.

“Alter” means to change a critical area or its buffer, including grading, filling, dredging, clearing, construction, compaction, excavation, and pollution.

“Anadromous” refers to fish that spawn and rear in freshwater and mature in saltwater.

“Applicant” means a person who applies for a development permit from the town.

“Aquifer” means a geological formation capable of yielding water to a well or spring.

“Best available science” means scientific information applicable to the critical area prepared by local, state, or federal natural resource agencies, a qualified scientific professional, or team of qualified scientific professionals that is consistent with criteria established in WAC 365-195-900 through WAC 365-195-925.

“Best management practices” means actions known to protect soil, water quality, vegetation, and critical areas.

“Buffer” means an area contiguous to and required for protection of a critical area.

“Channel migration zone” means the lateral extent of likely movement of a stream or river during the next 100 years as evidenced by movement over the past 100 years.

“Conservation easement” means a legal agreement that the property owner enters into to restrict uses of the land in a manner that conserves natural functions.

“Critical area” means wetlands, aquifer recharge areas, floodplains, geologically hazardous areas, and habitat conservation areas.

“Development” means any land use or action that alters a critical area or its buffer, including town approvals that establish patterns of use such as subdivisions, short subdivisions, rezones, and conditional use permits.

“Fish habitat” means habitat used by fish at any life stage at any time of the year.

“Functions and values” means the benefits conferred by critical areas, including water quality protection, fish and wildlife habitat, flood storage and conveyance, ground water recharge, erosion control, and protection from hazards.

“Hazardous substance” means a liquid, solid, or gas that exhibits any of the properties described in WAC 173-303-090 or 173-303-100.

“Historic” means existing before the area was altered by human activity.

“Impact” means to adversely affect a natural system or increase the hazard, which a natural system poses to human life and property.

“Impervious” refers to a hard surface area that retards the entry of water into the soil.

“Monitoring” means assessing the performance of mitigation measures by collection and analysis of data on changes in natural systems.

“Ordinary high-water mark” means that mark on the bed or bank below which inundation is so common in ordinary years that the soil and/or vegetation are distinct from that of the abutting upland.

“Person” means any person, organization, or other group.

“Primary association” means a relationship between a species and a habitat area whereby the species regularly uses or otherwise needs the habitat area to thrive.

“Rill” means a small, steep-sided channel caused by erosion.

“Riparian habitat” means streamside areas that influence the aquatic ecosystem by providing shade, debris, or insects and provide habitat for riparian wildlife.

“Species” means a group of animals commonly classified by the scientific community as a species or subspecies.

“Substantial improvement” means any repair, reconstruction, or improvement of a structure, the cost of which exceeds 50 percent of the structure’s market value before the improvement, or, if the structure was damaged, before the damage occurred.

“Watercourse” means flowing waters of the state, perennial or intermittent, excluding artificial waterways such as ditches or canals not created by human alteration of a natural watercourse.

“Wetland mitigation bank” means a site where wetlands are restored, created, or enhanced to mitigate in advance authorized impacts to similar resources.

1.4. Critical Areas Reports. Unless waived by the shoreline administrator, critical areas reports shall be prepared for proposed developments located within critical areas or their buffers. Said critical areas reports shall:

A. Be prepared by qualified professionals as defined in WAC 365-195-905(4). The following list shows the type of critical areas report and the related professional discipline:

1. Wetlands: wetland biologist,

2. Floodplains: hydrologist or engineer,

3. Geologically hazardous areas: engineer or geologist,

4. Fish and wildlife habitats: biologist;

B. Incorporate best available science;

C. Cover a study area large enough to understand relationships with important off-site factors and identify any nearby critical area whose buffer extends onto the project site;

D. Contain the following unless waived by the shoreline administrator:

1. Name and contact information of the applicant, description of the proposed development, and identification of required permits,

2. Site plan drawn to scale showing critical areas, buffers, existing structures, and proposed structures, clearing, grading, and storm water management,

3. Characterization of critical areas and buffers,

4. Assessment of the probable impact to critical areas,

5. Analysis of site development alternatives,

6. Description of efforts to avoid, minimize, and mitigate impacts to critical areas pursuant to Appendix B, Section 1.8 (Sequencing),

7. Mitigation plans as needed, in accordance with Appendix B, Section 1.6,

8. Evaluation of compliance with this critical areas code’s substantive requirements applicable to the proposed development,

9. Financial guarantees to ensure compliance, such as a performance bond or deposit, if necessary,

10. Additional information as required in the section corresponding to the type of critical area,

11. Documentation of who prepared the report and when, with fieldwork and data sheets,

12. Statement specifying the accuracy of the report and assumptions relied upon, and

13. Additional information as required by the shoreline administrator.

1.5. Pervious Surface. Critical areas reports may rely upon, without duplication of effort, valid previous studies prepared for the site, taking into account any change in the site, the proposed development, or the surrounding area.

1.6. Mitigation Plan Requirements. If the town allows conformance with these requirements to be achieved by mitigation, the critical areas report shall include a mitigation plan consisting of:

A. An analysis of the anticipated impacts on functions and values;

B. A strategy for mitigating the impacts, including site selection factors;

C. An analysis of the existing and anticipated functions and values at the mitigation site, including an assessment of risks;

D. A review of the best available science relative to the proposed mitigation;

E. Specific standards for evaluating whether the mitigation is successful;

F. Detailed construction plans, including:

1. Construction timing,

2. Grading and excavation details,

3. Erosion and sediment control features,

4. Planting plan including species and spacing, and

5. Measures to protect plants until established and control invasive species;

G. A program for monitoring the mitigation over at least five years; and

H. Potential corrective measures should the monitoring indicate the standards set per subsection E of this section are not being met.

1.7. Independent Review of Critical Areas Report. The shoreline administrator may have the critical areas report evaluated by an independent qualified professional and/or request consultation from an agency with expertise. If the report and evaluations disagree, the shoreline administrator shall determine which to utilize.

1.8. Substantive Requirements.

A. All treatment of critical areas shall be in accordance with the best available science as defined in WAC 365-195-900 through 365-195-925, which is hereby adopted by reference, along with the Washington State Department of Community Development’s “Citations of Recommended Sources of Best Available Science for Designating and Protecting Critical Areas.”

B. Critical areas and their buffers shall be left undisturbed except the following may be permitted if best management practices are used:

1. Authorized functional restoration;

2. In buffers: utility poles and utility lines, which do not require excavation;

3. In the outer 75 percent of buffers: permeable-surfaced walkways, trails, and minimal wildlife viewing structures;

4. Developments for which mitigation is allowed per subsection E of this section; and

5. Other uses specifically authorized by this critical areas code.

C. No development shall occur which results in a net loss of the functions or values of any critical area. The pre- and post-development functional comparison shall be on a per function basis unless otherwise authorized by this critical areas code.

D. No development shall occur in critical areas and their buffers, which results in an unreasonable hazard to the public health and safety.

E. These substantive requirements shall comply with the “sequencing” methods defined in WAC 173-26-201(2)(e)(i) as follows:

1. Avoiding the impact altogether by not taking a certain action or parts of an action;

2. Minimizing impacts by limiting the degree or magnitude of the action and its implementation by using appropriate technology or by taking affirmative steps to avoid or reduce impacts;

3. Rectifying the impact by repairing, rehabilitating, or restoring the affected environment;

4. Reducing or eliminating the impact over time by preservation and maintenance operations;

5. Compensating for the impact by replacing, enhancing, or providing substitute resources or environments; and

6. Monitoring the impact and the compensation projects and taking appropriate corrective measures.

Mitigation should provide equivalent or greater functions and values than those of the critical area it replaces. The mitigation shall be near the impact site unless it is more ecologically effective to mitigate lost functions at a larger scale, such as at a wetland mitigation bank within the impacted wetland’s drainage basin. The town reserves the right to disallow mitigation that would be located outside the UGA.

F. As a condition of any permit approval, the town may require that:

1. The outer edge of the critical area buffer be marked, signed, or fenced to protect the resource. Such protection may be temporary, during construction, or permanent such as to protect the resource from livestock or people. The shoreline administrator shall specify the design and sign message, if applicable, of such markers, signs, and fencing;

2. The applicant files a notice with the county records and elections division stating the presence of the critical area or buffer and the application of this critical areas code to the property, to inform subsequent purchasers of the property;

3. The critical area and/or buffer are placed in a critical area tract or conservation easement, the purpose of which is to set aside and protect the critical area. The critical area tract or conservation easement shall be:

a. Held by the town, a homeowner’s association, a land trust or similar conservation organization, or by each lot owner within the development in an undivided interest,

b. Recorded on all documents of title of record for the affected parcels,

c. Noted on the face of any plat or recorded drawing, and

d. Delineated on the ground with permanent markers and/or signs in accordance with local survey standards.

G. The town may allow averaging of standard wetland and stream buffer widths if a qualified professional demonstrates that:

1. Functions and values are not adversely affected;

2. The total buffer area is not reduced; and

3. At no location is the buffer width reduced more than 25 percent.

H. Unless otherwise provided, buildings and other structures shall be set back a distance of 10 feet from the edges of all critical area buffers. The same protrusions into this setback area shall be allowed as the zoning code allows into property line setback areas.

I. Lots created through subdivisions or short plats may contain critical areas and buffers provided they contain adequate buildable area to build upon. Subdivision and short plats shall show, on their face, any applicable critical area limitations.

J. When any existing regulation, easement, covenant, or deed restriction conflicts with this critical areas code, that which provides more protection to the critical areas shall apply.

K. When critical areas of two or more types coincide, the more restrictive buffer and requirements shall apply.

L. The substantive requirements peculiar to the type of critical area shall also be complied with. See following sections.

1.9. Enforcement and Inspections.

A. In enforcing these requirements, the shoreline administrator may require a restoration plan prepared by a qualified professional. Historic functions and values, soil configurations, and native vegetation shall be used as a guide for restoration. Flood and geological hazards shall be reduced to the pre-development level.

B. Reasonable access to the development shall be provided to agents of the town for critical area inspections, monitoring, restoration, or emergency action. [Ord. 580 Att. A App. B § 1, 2019.]

2. Wetlands.

2.1. Designation and Delineation. Identification of wetlands and delineation of their boundaries shall be done in accordance with the approved federal wetland delineation manual and the applicable regional supplements. All areas within the town of South Prairie meeting the wetland designation criteria, regardless of any formal identification, are hereby designated critical areas and are subject to the provisions of this chapter. The town of South Prairie has a map, showing the approximate location and extent of wetlands. However, the map is only a guide, and will be updated, as wetlands become better known. The exact location of a wetland’s boundary shall be determined in accordance with the above-stated approved federal wetland delineation manual as required by RCW 90.58.380.

2.2. Wetland Rating. Wetlands shall be rated Category I, II, III, or IV according to the Department of Ecology’s “2014 Washington State Wetland Rating System for Western Washington” (Publication #14-06-029, or as revised and approved by Ecology). Wetland categories shall apply to the wetland, as it exists on the date the town adopts the rating system, as the wetland naturally changes thereafter, or as the wetland changes in accordance with permitted activities. Wetland rating categories shall not change due to illegal modifications.

2.3. Contents of Critical Areas Reports. In addition to the requirements of Appendix B, Section 1.4, critical areas reports for wetlands shall include:

A. Wetland Delineation Map as Surveyed in the Field. Buffer boundaries shall be marked in the field by a licensed surveyor using wood or steel posts, four to five feet tall above the ground surface, permanently affixed, carrying identification signs approved by the town, to be obtained from the Town Hall. The charge for these signs shall be $1.00 per sign;

B. Assessment of wetlands, including acreage, category, required buffers, evidence of past illegal alterations, soil, topography, hydrology, ecology, and functional evaluation using a recognized method such as the Western Washington Wetland Rating System;

C. Discussion of measures to preserve wetland functions and values, including the “sequencing” set forth in Appendix B, Section 1.8;

D. If mitigation is proposed, a mitigation plan including the existing and proposed status of:

1. Wetland acreage,

2. Vegetation and fauna,

3. Surface and subsurface hydrology,

4. Soils, substrate, and topography,

5. Required wetland buffers, and

6. Property ownership, and

7. Proposed wetland management and monitoring.

2.4. Substantive Requirements. In addition to the substantive requirements in Appendix B, Section 1.8, the following requirements shall apply to developments (see definitions) in wetlands:

A. The higher the wetland category (Category I is highest), the greater shall be the emphasis on higher-priority “sequencing” methods per Appendix B, Section 1.8.

B. Buffer Requirements. The following buffer widths have been established in accordance with the best available science. They are based on the category of wetland and the habitat score as determined by a qualified wetland professional using the Washington State Wetland Rating System for Western Washington: 2014 Update (Ecology Publication No. 14-06-029, or as revised and approved by Ecology).

1. For wetlands that score six points or more for habitat function, the buffers in Table 2-1a can be used if both of the following criteria are met:

a. A relatively undisturbed, vegetated corridor at least 100 feet wide is protected between the wetland and any other “priority habitats” as defined by the Washington State Department of Fish and Wildlife. (The latest definitions of priority habitats and their locations are available on the WDFW website at The corridor must be protected for the entire distance between the wetland and the priority habitat by some type of legal protection such as a conservation easement. Presence or absence of a nearby habitat must be confirmed by a qualified biologist.

b. All of the measures in Table 2-2 are implemented, where applicable, to minimize the impact of the adjacent land uses.

2. For wetlands that score three to five habitat points, only the measures in Table 2-2 are required for the use of Table 2-1a.

3. If an applicant chooses not to apply the mitigation measures in Table 2-2 or is unable to provide a protected corridor where available, then Table 2-1b must be used.

4. The buffer widths in Tables 2-1a and 2-1b assume that the buffer is vegetated with a native plant community appropriate for the ecoregion. If the existing buffer is unvegetated, sparsely vegetated, or vegetated with invasive species that do not perform needed functions, the buffer should either be planted to create the appropriate plant community, or the buffer should be widened to ensure adequate functions of the buffer are provided.

C. Buffers shall be measured from the wetland boundary as surveyed in the field. If wetland enhancement is proposed, the category of the wetland after enhancement shall pertain.

D. The shoreline administrator may increase the required buffer width and/or require buffer enhancement if a wetland professional determines that the wetland provides habitat for wildlife species that require greater protection than the standard buffer, or the buffer lacks healthy native vegetation or is otherwise handicapped in its ability to protect the wetland. Said determination shall take into account the score derived from the wetland rating system and such factors as topography, land use, and past disturbance.

E. The shoreline administrator may reduce the standard buffer width if the function(s) served by the particular wetland need less buffer width, as indicated by a wetland functional analysis.

F. Except as provided elsewhere in these requirements, all existing native vegetation in wetland buffers shall be retained without disturbance, mowing, or hard surfacing, nor shall any action be taken to inhibit volunteer regrowth of native vegetation. Invasive weeds shall be removed for the duration of any mitigation bond. Storm water management facilities and bioswales are permitted in the outer 50 percent of the buffer of Category III or IV wetlands provided wetland functions and values are not significantly lost through fluctuations in wetland hydrology and construction integrates best management practices.

Table 2-1a. Wetland Buffer Requirements if Table 2-2 is Implemented and Corridor Provided

Buffer Width (in Feet) Based on Habitat Score

Wetland Category




Category I: Based on total score




Category I: Wetlands of high conservation value




Category I: Forested




Category II: Based on total score




Category III




Category IV




Table 2-1b. Wetland Buffer Requirements if Table 2-2 is NOT Implemented, or Corridor NOT Provided

Buffer Width (in Feet) Based on Habitat Score

Wetland Category




Category I: Based on total score




Category I: Wetlands of high conservation value




Category I: Forested




Category II: Based on total score




Category III




Category IV


Table 2-2. Required Measures to Minimize Impacts to Wetlands

(All measures are required if applicable to a specific proposal)


Required Measures to Minimize Impacts


• Direct lights away from wetland


• Locate activity that generates noise away from wetland

• If warranted, enhance existing buffer with native vegetation plantings adjacent to noise source

• For activities that generate relatively continuous, potentially disruptive noise, such as certain heavy industry or mining, establish an additional 10' heavily vegetated buffer strip immediately adjacent to the outer wetland buffer

Toxic runoff

• Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered

• Establish covenants limiting use of pesticides within 150' of wetland

• Apply integrated pest management

Storm water runoff

• Retrofit storm water detention and treatment for roads and existing adjacent development

• Prevent channelized flow from lawns that directly enters the buffer

• Use low intensity development techniques (for more information refer to the drainage ordinance and manual)

Change in water regime

• Infiltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces and new lawns

Pets and human disturbance

• Use privacy fencing OR plant dense vegetation to delineate buffer edge and to discourage disturbance using vegetation appropriate for the ecoregion

• Place wetland and its buffer in a separate tract or protect with a conservation easement


• Use best management practices to control dust

2.5. Mitigation.

A. Mitigation for alterations to wetlands may be by restoring former wetlands, creating wetlands, or enhancing degraded wetlands, consistent with Wetland Mitigation in Washington State – Part 1: Agency Policies and Guidance, Publication #06-06-011a, March 2006, and Wetland Mitigation in Washington State – Part 2: Developing Mitigation Plans, Publication #06-06-011b, March 2006.

B. Mitigation shall generally replace wetland functions lost from the altered wetland except that the town may permit out-of-kind replacement when the lost functions are minimal or less important to the drainage basin than the functions that the mitigation action seeks to augment.

C. Mitigation shall be in the same drainage basin as the altered wetland. Wetland mitigation shall be in the same sub-basin unless a higher level of ecological functioning would result from an alternate approach.

D. Mitigation projects shall be completed as quickly as possible consistent with such factors as rainfall and seasonal sensitivity of fish, wildlife, and flora.

E. Mitigation projects shall be designed with reference to Wetland Mitigation in Washington State – Part 1: Agency Policies and Guidance, Publication #06-06-011a, March 2006; and similar science. Mitigation projects shall score the impact site and the mitigation site using the Wetland Rating Data Form of the Department of Ecology’s “2014 Washington State Wetland Rating System for Western Washington” (Publication #14-06-029, or as revised and approved by Ecology). The aggregate total of wetland functions and values after mitigation, altered and mitigation sites combined, shall be at least 50 percent greater than the aggregate total before mitigation; provided, that this replacement ratio (1.5 to 1, nonacreage-based) shall be increased as necessary to compensate for mitigation that:

1. Has a greater than usual risk of failure;

2. Is out-of-kind;

3. Is outside the sub-basin;

4. Is unlikely to produce the intended functions and values within 10 years after the alteration; or

5. Remedies unauthorized alterations.

F. Because the above replacement ratio is based on a before-and-after count of functions and values, not acreage, it accounts, without need for further adjustment, for mitigation that would result in a lower category wetland than the wetland being impacted, and mitigation that would enhance as opposed to create or restore a wetland. In the case of enhancement, wetland acreage may decline though wetland functions and values would increase. Enhancement proposals shall be based on a sound understanding of the mitigation site’s pre- and post-mitigation functions and values.

G. Credits granted from a certified wetland mitigation bank shall be consistent with the bank’s certification and service area.

H. The applicant shall provide an as-built plan of the mitigation site and monitor the site in accordance with Appendix B, Section 1.6. [Ord. 580 Att. A App. B § 2, 2019.]

3. Geologically Hazardous Areas.

3.1. Designation. Areas susceptible to one or more of the following types of hazards are hereby designated geologically hazardous areas, in accordance with WAC 365-190-080(4)(a):

A. Erosion hazard areas are areas identified by the U.S. Department of Agriculture’s Natural Resources Conservation Service as having a moderate-to-severe, severe, or very severe rill and inter-rill (sheet wash) erosion hazard.

B. Landslide hazard areas are areas subject to landslides based on geology, soils, topography, and hydrology, including:

1. Areas delineated by the U.S. Department of Agriculture’s Natural Resources Conservation Service as having a severe limitation for building site development;

2. Areas mapped by the Washington Department of Ecology (Coastal Zone Atlas) or the Washington State Department of Natural Resources (slope stability mapping) as unstable (U or Class 3), unstable old slides (UOS or Class 4), or unstable recent slides (URS or Class 5);

3. Areas designated as quaternary slumps, earthflows, mudflows, lahars, or landslides on maps published by the U.S. Geological Survey or Washington State Department of Natural Resources;

4. Areas where the following coincide: slopes steeper than 15 percent, a relatively permeable sediment overlying a relatively impermeable sediment or bedrock, and ground water seepage;

5. Areas that have shown movement in the past 10,000 years or that are underlain or covered by mass wastage debris of that time frame;

6. Slopes that are parallel or subparallel to planes of weakness (such as bedding planes, joint systems, and fault planes) in subsurface materials;

7. Slopes steeper than 80 percent subject to rock fall during seismic shaking;

8. Areas potentially unstable because of rapid stream incision, stream bank erosion, and undercutting by wave action;

9. Areas at risk from snow avalanches;

10. Canyons or active alluvial fans subject to debris flows or catastrophic flooding; and

11. Slopes of 30 percent or steeper with a vertical relief of 19 or more feet except areas composed of consolidated rock.

C. Seismic hazard areas are areas subject to severe risk of damage as a result of earthquake-induced ground shaking, slope failure, settlement, soil liquefaction, lateral spreading, or surface faulting. One indicator of potential earthquake damage is a record of past earthquake damage. Settlement and soil liquefaction occur in areas underlain by cohesionless, loose, or soft-saturated soils of low density, typically in association with a shallow ground water table.

D. Mine hazard, volcanic, and tsunami hazard areas (none known to be present: see WAC 365-190-080).

E. Other hazard areas include areas susceptible to mass wasting, debris flows, rock falls, and differential settlement.

3.2. Mapping. The following maps, which may be continuously updated, may be used as a guide for locating geologically hazardous areas:

A. U.S. Geological Survey landslide hazard, seismic hazard, and volcano hazard maps;

B. Washington State Department of Natural Resources seismic hazard maps for Western Washington;

C. Washington State Department of Natural Resources slope stability maps;

D. Locally adopted maps.

3.3. Contents of Critical Areas Reports. In addition to the requirements of Appendix B, Section 1.4, critical areas reports for geologically hazardous areas shall include, where applicable:

A. Site history regarding landslides, erosion, and prior grading;

B. Topography in suitable contour intervals;

C. Height of slope, slope gradient, slope stability, and slope retreat rate recognizing potential catastrophic events;

D. Description of the geology (including faults), hydrology (including springs, seeps, and surface runoff features), soils (including, in seismic hazard areas, thickness of unconsolidated deposits and liquefaction potential), and vegetation;

E. Type, extent, and severity of geologic hazard(s);

F. Analysis of the proposal’s risk from geologic hazard and the proposal’s potential for exacerbating off-site hazards;

G. Recommended Buffers and Other Conditions of Approval. In areas of erosion or landslide hazard, the recommended conditions may include:

1. Clearing, fill, and hard-surfacing limits, slope stabilization measures, and vegetation management plan,

2. Limitation on clearing during the rainy season, generally from October 1st to May 1st,

3. Design parameters of foundations and retaining structures, and

4. Drainage plan and erosion and sediment control plan in compliance with town storm water management regulations; and

H. Overview of field investigations, measurements, references, and past assessments of the site.

3.4. Substantive Requirements. In addition to the substantive requirements of Appendix B, Section 1.8, the following requirements shall apply to geologic hazard areas:

A. Proposed developments shall not increase the long-term risk of or exposure to geological hazard on-site or off-site.

B. Hazard mitigation shall not rely on actions that require extensive maintenance.

C. Development near an erosion or landslide hazard area shall:

1. Observe a buffer from the edges thereof, of adequate width to comply with the substantive requirements;

2. Not decrease the factor of safety for landslides below the limits of 1.5 for static conditions and 1.2 for dynamic conditions. Analysis of dynamic conditions may be based on a minimum horizontal acceleration as established by the International Building Code;

3. Cluster structures and improvements as necessary to avoid hazard areas;

4. Use retaining walls that allow the retention of existing natural slopes when possible rather than graded artificial slopes;

5. Place utility lines and pipes in erosion and landslide hazard areas only when no other alternative is available and when the line or pipe can be installed above ground in such a manner as to remain intact without leaks in the event of a slide;

6. Discharge water from surface water facilities and roof drains onto or upstream from an erosion or landslide hazard area only if:

a. Discharged at flow durations matching predeveloped conditions, with adequate energy dissipation, into existing channels, or

b. Dispersed upslope of the steep slope onto a low-gradient undisturbed buffer of adequate infiltrate capacity without increasing saturation of the slope; and

7. Locate any on-site sewage drain fields outside the hazard area and related buffers. [Ord. 580 Att. A App. B § 3, 2019.]

4. Habitat Conservation Areas.

4.1. Designation. Habitat conservation areas include:

A. Areas having a primary association with fish and wildlife species identified by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service as being in danger of extinction or threatened to become endangered;

B. Areas having a primary association with fish and wildlife species identified by the Washington Department of Fish and Wildlife as being in danger of extinction, threatened to become endangered, vulnerable, or declining and are likely to become endangered or threatened in a significant portion of their range within the state without cooperative management or removal of threats. See WAC 220-610-010 (state endangered species) and WAC 220-200-100 (state threatened and sensitive species);

C. State priority habitats as identified by the State Department of Fish and Wildlife;

D. Habitats and species of local importance as identified by the town in accordance with Appendix B, Section 4.2;

E. Waters of the state, including lakes, rivers, ponds, streams, inland waters, underground waters, salt waters, and all other surface waters and watercourses within the jurisdiction of the state of Washington, as classified in WAC 222-16-031;

F. Ponds under 20 acres that provide fish or wildlife habitat except artificial ponds created for a nonwildlife purpose such as storm water detention facilities, wastewater treatment facilities, farm ponds, and temporary construction ponds;

G. Lakes, ponds, streams, and rivers planted with game fish by a governmental or tribal entity;

H. Natural area preserves and natural resource conservation areas as defined by the Washington State Department of Natural Resources;

I. Areas of rare plant species and high-quality ecosystems as identified by the Washington State Department of Natural Resources through the Natural Heritage Program (see Chapter 79.70 RCW); and

J. Land useful or essential for preserving connections between habitat blocks and open spaces.

4.2. Designation of Habitats and Species of Local Importance.

A. Nominations for habitats and species of local importance shall include:

1. Precise identification of the nominated habitat;

2. A scientifically sound management plan; and

3. A study, paid for by the nominator, containing sufficient information to verify compliance with the following criteria.

B. The designation criteria shall be as follows:

1. The species shall be local, native populations that are vulnerable, declining, or have special recreation, commercial, game, or other value;

2. The habitat shall be important for the long-term persistence of the local population;

3. The habitat shall be of high quality, or be capable of restoration to high quality, or connect otherwise isolated habitats;

4. Protection by other agencies, laws, or nonregulatory tools shall be inadequate to protect the species.

C. Designations of habitats and species of local importance shall form a part of these development regulations.

4.3. Mapping. The following maps, which may be continuously updated, may be used as a guide for locating habitat conservation areas:

A. Washington Department of Fish and Wildlife Priority Habitat and Species maps;

B. Washington State Department of Natural Resources, Official Water Type Reference maps;

C. Washington State Department of Natural Resources Shorezone Inventory;

D. Washington State Department of Natural Resources Natural Heritage Program mapping data;

E. Anadromous and resident salmonid distribution maps contained in the habitat limiting factors reports published by the Washington Conservation Commission; and

F. Washington State Department of Natural Resources State Natural Area Preserves and Natural Resource Conservation Area maps.

4.4. Content of Critical Areas Reports. In addition to the general critical areas report requirements of Appendix B, Section 1.4, critical areas reports for habitat conservation areas shall include, where applicable:

A. Vegetation assessment; and

B. Discussion of any federal, state, or local special management recommendations for species or habitats on near the site.

4.5. Substantive Requirements. In addition to the substantive requirements of Appendix B, Section 1.8, the following shall apply to habitat conservation areas:

A. No plant, wildlife, or fish species not indigenous to the region shall be introduced into a habitat conservation area except with approval of a state or federal agency with expertise.

B. Preference in mitigation shall be given to contiguous wildlife habitat corridors.

C. In reviewing development proposals, the town shall seek opportunities to restore degraded riparian fish and wildlife functions such as breeding, rearing, migration, and feeding.

D. The town shall require buffers of undisturbed native vegetation adjacent to habitat conservation areas as necessary. Buffer widths shall reflect the sensitivity of the habitat and may reflect the intensity of nearby human activity.

E. When a species is more sensitive to human activity during a specific season of the year, the town may establish an extra outer buffer from which human activity is excluded during said season.

F. No development shall be allowed within a habitat conservation area or buffer with which state or federal endangered, threatened, or sensitive species have a primary association, except in exchange for restoration as approved by the shoreline administrator or as provided in a management plan approved by a state or federal agency with appropriate expertise.

G. When a development permit is applied for on land containing or adjacent to a bald eagle nest or communal roost, the town shall notify the Washington Department of Fish and Wildlife and otherwise comply with WAC 220-610-100.

H. No development shall be permitted which degrades the functions or values of anadromous fish habitat, including structures or fills which impact migration or spawning.

I. Construction and other activities shall be seasonally restricted as necessary to protect the resource. Activities shall be timed to occur during work windows designated by the Washington Department of Fish and Wildlife for applicable fish species.

J. Shoreline erosion control shall use bioengineering methods or soft armoring in accordance with an approved critical areas report.

K. The following table establishes the standard width of nonshoreline stream buffers (also known as riparian habitat areas) that shall apply to each stream type. The town of South Prairie has maps showing streams of each type. Widths shall be measured outward in each direction, on the horizontal plane, from the ordinary high-water mark, or from the top of bank if the ordinary high-water mark cannot be identified, or from the outer edge of the channel migration zone when present.

Stream Buffers in Riparian Habitat Areas

Stream Type

Standard Buffer Width

Type F

100 feet

Type Np

50 feet

Type Ns

25 feet

L. The shoreline administrator may increase the standard buffer width as necessary to fully protect riparian functions. For example, the buffer may be extended to the outer edge of the floodplain or windward into an area of high tree blow-down potential.

M. The shoreline administrator may reduce the standard buffer width in exchange for restoration of degraded areas in accordance with an approved plan, or for buffer averaging in accordance with Appendix B, Section 1.8. The shoreline administrator may also reduce the standard buffer width wherever the proposed adjoining upland land use is of low intensity and low impact, such as passive-use parks.

N. If the stream enters an underground culvert or pipe, and is unlikely to ever be restored aboveground, the shoreline administrator may waive the buffer along the undergrounded stream; provided, that where the stream enters and emerges from the pipe the opposite outer edges of the buffer shall be joined by a radius equal to the buffer width, with said radius projecting over the piped stream.

O. To the extent facilities are allowed in habitat conservation areas, the following regulations shall apply:

1. Trails shall be on the outer edge of the stream buffer except for limited viewing platforms and crossings. Trails and platforms shall be of pervious materials as far as possible.

2. Road bridges and culverts shall be designed according to the Washington Department of Fish and Wildlife Fish Passage Design at Road Culverts, 1999, and the National Marine Fisheries Service Guidelines for Salmonid Passage at Stream Crossings, 2000.

3. Utility lines shall be accomplished by boring beneath the scour depth and hyporheic zone (the saturated zone beneath and adjacent to streams that filters nutrients and maintains water quality). Utilities shall avoid paralleling streams or changing the natural rate of shore or channel migration.

4. New and expanded public flood protection measures shall require a biological assessment approved by the agency responsible for protecting federally listed species.

5. In-stream structures such as high-flow bypasses, sediment ponds, instream ponds, retention and detention facilities, tide gates, dams, and weirs shall be allowed only as part of an approved restoration project.

6. Storm water conveyance structures shall incorporate fish habitat features and the sides of open channels and ponds shall be vegetated to retard erosion, filter sediments, and shade the water.

7. Watercourse alterations: see Chapter 15.18 SPMC (Critical Areas). [Ord. 580 Att. A App. B § 4, 2019.]