Chapter 18.24 CRITICAL AREAS*

The purpose of this chapter is to implement the goals and policies of the Washington State Environmental Policy Act, Chapter 43.21C RCW, the Growth Management Act, Chapter 36.70A RCW, the Federal Endangered Species Act, and the city of Newcastle comprehensive plan which call for protection of the natural environment and the public health and safety while reflecting the local conditions and priorities of the city of Newcastle by:

A. Establishing development standards to protect and encourage restoration and enhancement of defined critical areas;

B. Protecting members of the general public and public resources and facilities from injury, loss of life, property damage or financial loss due to flooding, erosion, landslides, seismic events, soil subsidence or steep slope failures;

C. Protecting unique, fragile and valuable elements of the environment including, but not limited to, wetlands, streams, fish and wildlife habitat and species diversity;

D. Preventing cumulative adverse environmental impacts on water availability, water quality, wetlands and streams;

E. Achieve no net loss of core preservation areas within fish and wildlife habitat conservation areas, which include riparian corridors, and minimize impact to and retain character of quality habitat areas, and protect species of concern, priority species, and species of local importance;

F. Measuring the quantity and quality of wetland and stream resources and preventing overall net loss of wetland and stream functions, value and acreage and where possible enhance and restore wetland areas;

G. Achieve no net loss of structure, value, and functions of natural systems within frequently flooded areas and employ no net impact floodplain management in order to avoid impacts to upstream and downstream properties and substantial risk and damage to public and private property and loss of life;

H. Direct activities not dependent on critical area resources to less environmentally sensitive sites and mitigate unavoidable impacts to critical areas by regulating alterations in and adjacent to critical areas;

I. Alerting members of the public including, but not limited to, appraisers, owners, potential buyers or lessees to the development limitations of critical areas;

J. Meeting the requirements of the National Flood Insurance Program and maintaining the city as an eligible community for federal flood insurance benefits;

K. Alerting members of the general public to the development limitations of critical areas;

L. Serve as a basis for exercise of the city’s substantive authority under the State Environmental Policy Act (SEPA) and the city’s SEPA rules; and

M. Protect critical areas in accordance with the Growth Management Act and through the application of best available science, as determined according to WAC 365-195-900 through 365-195-925, and in consultation with state and federal agencies and other qualified professionals. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.020 Applicability.

A. The provisions of this chapter shall apply to all land uses in the city, and all persons within the city shall comply with the requirements of this chapter. Regulated uses and activities include, but are not limited to, the following:

1. Removal, excavation, or grading of soil;

2. Dredging, dumping, or discharging of material;

3. Filling, draining, or flooding of an area;

4. Construction, or expansion of any structure or infrastructure that results in the disturbance of a critical area or the addition of any impervious surface coverage to a site;

5. Clearing or other major alteration of vegetation;

6. Activities affecting surface or groundwater resources including quantity and pollutants.

B. The city shall not approve any permit or otherwise issue any authorization to alter the condition of any land, water or vegetation or to construct or alter any structure or improvement without first assuring compliance with the requirements of this chapter.

C. Approval of a development proposal pursuant to the provisions of this chapter does not discharge the obligation of the applicant to comply with the provisions of this chapter.

D. When any provision of any other chapter of the city code conflicts with this chapter or when the provisions of this chapter are in conflict, that provision which provides more protection to environmentally critical areas shall apply unless specifically provided otherwise in this chapter or unless such provision conflicts with federal or state laws or regulations.

E. The provisions of this chapter shall apply to all forest practices over which the city has jurisdiction pursuant to Chapter 76.09 RCW and WAC Title 222. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.030 Appeals.

Any decision to approve, condition or deny a development proposal based on the requirements of this chapter may be appealed according to and as part of the appeal procedure for the permit or approval involved. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.040 Critical areas rules.

Applicable departments within the city are authorized to adopt such administrative rules and regulations as are necessary and appropriate to implement this chapter and to prepare and require the use of such forms as are necessary to its administration. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.050 Exemptions.

The following activities are exempt from the provisions of this chapter:

A. Alterations in response to emergencies which threaten the public health, safety and welfare or which pose an imminent risk of damage to property as long as any alteration undertaken pursuant to this subsection is reported to the city immediately. The director shall confirm that an emergency exists and determine what, if any, mitigation shall be required to protect the health, safety, welfare and environment and to repair any resource damage;

B. Existing and ongoing agricultural activities provided no alteration of flood storage capacity or conveyance occurs and the activity does not adversely affect critical areas;

C. Activities involving artificially created wetlands or streams intentionally created from nonwetland sites, including but not limited to grass-lined swales, irrigation and drainage ditches, detention facilities, and landscape features, except wetlands, streams, or swales created as mitigation or that provide habitat for fish;

D. Public water, electric and natural gas distribution, public sewer collection, cable communications, telephone utility and related activities undertaken pursuant to city-approved best management practices, and designed to avoid and minimize impacts to critical areas where possible subject to the exemptions listed below. When activities occur in wetlands or other waters state and federal permitting approval shall be required.

1. Normal and routine maintenance or repair of existing improved utility structures or rights-of-way;

2. Relocation of electric facilities, lines, equipment or appurtenances, not including substations, with an associated voltage of 55,000 volts or less, only when required by a local governmental agency which approves the new location of the facilities;

3. Replacement, operation, repair, modification or installation or construction in an improved public road right-of-way of all electric facilities, lines, equipment or appurtenances, not including substations, with an associated voltage of 55,000 volts or less when such facilities are located within an improved public road right-of-way or the city-authorized private roadway;

4. Relocation of public sewer local collection, public water local distribution, natural gas, cable communication or telephone facilities, lines, pipes, mains, equipment or appurtenances, only when required by a local governmental agency which approves the new location of the facilities; and

5. Replacement, operation, repair, modification, installation or construction of public sewer local collection, public water local distribution, natural gas, cable communication or telephone facilities, lines, pipes, mains, equipment or appurtenances when such facilities are located within an improved public right-of-way or the city-authorized private roadway;

E. Maintenance, operation, repair or replacement of publicly improved roadways, as long as any such alteration does not involve the expansion of roadways or related improvements into previously unimproved rights-of-way or portions of rights-of-way when such facilities are located within an improved public right-of-way or city-authorized private roadway;

F. Maintenance, operation or repair of publicly improved recreation areas, as long as any such alteration does not involve the expansion of improvements into previously unimproved recreation areas;

G. Public agency development proposals only to the extent of any construction contract awarded before the date of incorporation; provided, that any law or regulation in effect at the time of such award shall apply to the proposal;

H. Measures to control a fire or halt the spread of disease or damaging insects; provided, that the removed vegetation shall be replaced in-kind or with similar native species within one year pursuant to a restoration plan meeting the requirements of NMC 18.24.130, Mitigation and monitoring. Replacement trees may be planted at a different nearby location within the critical area buffer if it can be determined that planting in the same location would create a new fire hazard or potentially damage the critical area. Replacement trees shall be species that are native and indigenous to the site and minimum of one inch in diameter-at-breast height (dbh) for deciduous trees and a minimum of six feet in height for evergreen trees as measured from the top of the root ball;

I. Structural modification of, addition to, repair or reconstruction of structures, except single detached residences, in existence before the date of incorporation which do not meet the building setback or buffer requirements for wetlands, streams or steep slope hazard areas if the modification, addition, replacement or related activity does not increase the existing footprint of the structure lying within the above-described building setback area, critical area or buffer. Repair or reconstruction of structures shall only be permitted when the structure is damaged or partially destroyed and the requirements of NMC 18.32.070, Nonconformance – Repair or reconstruction of nonconforming structure, have been met;

J. Structural modification of, addition to, repair or reconstruction of single detached residences in existence before the date of incorporation which do not meet the building setback or buffer requirements for wetlands, streams or steep slope hazard areas if the modification, addition, replacement or related activity does not increase the existing footprint of the residence lying within the above-described buffer or building setback area by more than 250 square feet over that existing before the date of incorporation and no portion of the modification, addition or replacement is located closer to the critical area or, if the existing residence is in the critical area, extends farther into the critical area. Repair or reconstruction of structures shall only be permitted when the structure is damaged or partially destroyed and the requirements of NMC 18.32.070(B) and (C), Nonconformance – Repair or reconstruction of nonconforming structure, have been met;

K. Maintenance or repair of structures which do not meet the development standards of this chapter for landslide or seismic hazard areas if the maintenance or repair does not increase the footprint of the structure and there is no increased risk to life or property as a result of the proposed maintenance or repair;

L. The grazing of livestock is exempt from the provisions of this chapter and any administrative rules promulgated thereunder, except for the livestock restriction provisions and any animal density limitations established by law, if the grazing activity was in existence before the date of incorporation;

M. A permit or approval sought as part of a development proposal for which multiple permits are required is exempt from the provisions of this chapter and any administrative rules promulgated thereunder, except for the notice on title provisions, NMC 18.24.170 through 18.24.180, if:

1. The city previously reviewed all critical areas on the site;

2. There is no material change in the development proposal since the prior review;

3. There is no new information available which is important to any critical area review of the site or particular critical area;

4. The permit or approval under which the prior review was conducted has not expired or, if no expiration date, no more than five years have elapsed since the issuance of that permit or approval; and

5. Compliance with any standards or conditions placed upon the prior permit or approval has been achieved or secured; and

N. Normal and routine maintenance and operation of existing landscaping and gardens provided they comply with all other regulations in this chapter. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.060 Reserved.

(Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.070 Reasonable use exceptions.

A. Critical Areas Reasonable Use Exception – Public Project. Any public agency or city department claiming that strict application of these standards would deny construction of a public project may apply for a critical areas reasonable use exception – public project under Chapter 18.44 NMC, Decision Criteria, critical areas reasonable use (public project).

B. Critical Areas Reasonable Economic Use Exception – Private Property. These standards and regulations are not intended, and shall not be construed or applied in a manner, to deny all reasonable economic use of private property. Any private property owner who claims that strict application of these standards would deny all reasonable economic use of their property may apply for an exception under Chapter 18.44 NMC, Decision Criteria, critical areas reasonable economic use (private). (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2001-248 § 39; Ord. 2000-224 § 1).

18.24.075 Relationship to other regulations.

A. These critical area regulations shall apply as an overlay and in addition to zoning, land use, and other regulations established by the city of Newcastle. When any provision of any other chapter of the city code conflicts with this chapter or when the provisions of this chapter are in conflict, that provision which provides more protection to environmentally critical areas shall apply unless specifically provided otherwise in this chapter or unless such provision conflicts with federal or state laws or regulations.

B. Compliance with the provisions of this title does not constitute compliance with other federal, state, and local regulations and permit requirements that may be required (for example, shoreline substantial development permits, HPA permits, Army Corps of Engineers Section 404 permits, NPDES permits). The applicant is responsible for complying with these requirements. Where applicable, the designated official will encourage use of information such as permit applications to other agencies or special studies prepared in response to other regulatory requirements to support required documentation submitted for critical areas. (Ord. 2022-645 § 11; Ord. 2016-538 § 2 (Exh. 3)).

18.24.080 Critical area maps and inventories.

The distribution of many environmentally critical areas in the city is displayed on various resources including but not limited to previous studies, county-wide maps, and comprehensive plan maps. Information about flood hazard areas mapped by the Federal Insurance Administration is included in Chapter 14.25 NMC. If there is a conflict among the maps, inventory, and site-specific features, the actual presence or absence of the features defined in this title as critical areas shall govern. Any preexisting maps or studies shall be used as a general guide only for the assistance of property owners and other interested parties. It is presumed that critical areas not shown on these maps may exist in the city. These critical areas not currently mapped are protected under all the provisions of this code. The actual type, extent, and boundaries of critical areas shall be determined in the field by a qualified consultant according to the procedures and criteria established by this chapter. In the event of any conflict between the critical area location and designation shown on the city’s map and the criteria or standards of this section, the criteria and standards shall prevail. (Ord. 2022-645 § 11; Ord. 2021-624 § 15; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.085 Fish habitat use – Rebuttal of presumption.

The presumption in NMC 18.06.686 that a stream is used by fish may be rebutted by:

A. Documenting a lawful blockage which prevents fish from entering a stream or portion thereof, and the stream has no known resident fish present; or

B. Subject to the conditions of any Washington Department of Fish and Wildlife scientific sampling permit, sampling carried out by trapping or electrofishing the stream or other applicable water body during the high flow period from January 31st through March 31st which shows that fish are not present. The department may require a second sampling if it determines that conditions, such as flooding or other circumstances, impaired the accuracy of the first sampling. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.090 Disclosure by applicant.

A. The applicant shall disclose to the city the presence of critical areas on the development proposal site and any mapped or identifiable critical areas within 300 feet of the applicant’s property.

B. If the development proposal site contains or is within a critical area, the applicant shall submit an affidavit which declares whether the applicant has knowledge of any illegal alteration to any or all critical areas on the development proposal site and whether the applicant previously has been found in violation of this chapter, pursuant to Chapter 18.50 NMC, Enforcement. If the applicant previously has been found in violation, the applicant shall declare whether such violation has been corrected to the satisfaction of the city. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.100 Critical area review.

A. The city shall perform a critical area review for any city development proposal permit application or other request for permission to proceed with an alteration on a site which includes a critical area or is within an identified critical area buffer or building setback area.

B. As part of the critical area review, the city shall:

1. Determine whether any critical area exists on the property and confirm its nature and type;

2. Determine whether a critical area report is required, and if so:

a. Evaluate the critical area report and determine whether it contains all information required in this chapter;

b. Determine whether the development proposal is consistent with this chapter;

c. Determine whether any proposed alteration to the critical area or buffer is necessary; and

d. Determine if the mitigation and monitoring plans and bonding measures proposed by the applicant are sufficient to protect the public health, safety and welfare, consistent with the goals, purposes, objectives and requirements of this chapter. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.110 Critical area report requirement.

A. Except as otherwise provided in this section, an applicant for a development proposal on a site which includes a critical area or is within a critical area buffer or associated building setback area shall submit a critical area report to the department to adequately evaluate the proposal and all probable impacts.

B. All reports and studies required of the applicant by this section shall be prepared by a qualified consultant. The city may, at its discretion and at the applicant’s expense, retain a qualified consultant to review and confirm the applicant’s reports, studies, and plans.

C. The department may waive the requirement for a critical area report if the applicant shows, to the department’s satisfaction, that:

1. There will be no alteration of the critical area or buffer;

2. The development proposal will not have an impact on the critical area in a manner contrary to the purpose and requirements of this chapter; or

3. Adequate information exists for the department to evaluate any impacts upon the critical area.

D. If necessary to ensure compliance with this chapter, the city may require additional information from the applicant, separate from the critical area report. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.120 Contents of critical area report – General requirements.

A. At a minimum a critical areas study shall be prepared at the applicant’s expense, to identify and characterize any critical area as a part of the larger development proposal site; assess any hazards to the proposed development; assess impacts of the development proposal on any critical areas located on or adjacent to the development proposal site; and assess the impacts of any alteration proposed for a critical area. Studies shall propose adequate mitigation, maintenance and monitoring plans and bonding measures. Critical areas studies shall include, among other requirements, a scale map of the development proposal site and a written report. The critical area report shall contain any or all of the following, as required by the department based upon its evaluation of the permit application or the development proposal site:

1. Identification and characterization of all critical areas and associated buffers on the development proposal site, including, but not limited to:

a. Delineations of flood hazard, coal mine hazard, erosion hazard, seismic hazard, landslide hazard areas, steep slopes, wetlands, and/or the ordinary high water marks of regulated waters even if they are within the limits of other critical areas and their buffers;

b. Historical data including, but not limited to, original and subsequent mapping and inventories, aerial photographs, data compilations and summaries, and available reports and records relating to the site or past operations at the site;

c. A statement by a qualified professional specifying the accuracy of the identification and characterization of the critical area and the basis for the statement including, but not limited to, all assumptions made and relied upon;

d. A bibliography of published information referenced, including maps and best available science materials;

e. Identification and characterization of surface and subsurface conditions of coal mine and landslide hazard areas;

f. A summary description of reasonable efforts made to apply mitigation sequencing pursuant to NMC 18.24.125, Avoiding impacts to critical areas, to avoid, minimize, and mitigate impacts to critical areas;

2. Assessment of the impacts of any development proposal, including an analysis of alternatives demonstrating that all reasonable effort has been made to mitigate impacts, including, but not limited to:

a. The impacts of any proposed alteration of a critical area or buffer on the critical area;

b. The impacts of any proposed development adjacent to a critical area or buffer on the critical area; and

c. The impacts of any proposed alteration of a critical area or buffer on the development proposal, other properties and the environment;

3. Plans for adequate mitigation and financial guarantees to offset any impacts, including but not limited to:

a. The impacts to on-site and affected off-site critical areas; and

b. The impacts of any proposed alteration of a critical area or buffer on the development proposal, other properties, and the environment;

4. A copy of the site plan for the development proposal showing:

a. A description and maps at a scale no smaller than one inch equals 50 feet (unless otherwise approved by the department), showing the entire parcel of land owned by the applicant; adjacent area; and the exact boundary of the critical area on the parcel as determined in compliance with appropriate section of this chapter. Maps can be overlaid on aerial photographs;

b. Identified critical areas, buffers and the development proposal with dimensions indicating distances between;

c. Limits of any areas to be disturbed;

d. All natural and manmade features within the maximum buffer area of any critical area within a radius of 50 feet from the site;

e. The layout of any underground coal mines and the location of any associated surface features and remedial work carried out to mitigate hazards;

5. Descriptions, including dates and names of persons responsible, and available documentation and logs of any fieldwork performed on the site including, but not limited to:

a. Surveys;

b. Site delineations; and

c. Exploratory drilling and testing to investigate subsurface conditions;

6. Plans, such as grading and drainage plans;

7. Documentation supporting any requested exemption or exception from or modification of buffer or other critical area requirements;

8. Interim and final results and recommendations including, but not limited to, the results of hazard assessments.

B. For emergency actions taken pursuant to NMC 18.24.050(A), the critical area report shall include, at minimum, a description of the alteration and resulting impacts and a proposed mitigation plan, in compliance with this chapter.

C. Unless otherwise provided, a critical area report may be supplemented by or comprised of, in whole or in part, any reports or studies required by other laws and regulations or previously prepared for and applicable to the development proposal site, as approved by the department.

D. A critical area report may be required to be produced or presented to the department in more than one stage when the department’s evaluation of the proposal or ability to determine the needed contents of a critical area report is dependent upon interim studies or results.

E. If the development proposal will affect only a part of the development proposal site, the department may limit the scope of the required critical area report to include only that part of the site which may be affected by the development. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.125 Avoiding impacts to critical areas.

An applicant for a development proposal or alteration shall apply the following sequential measures, which appear in order of priority, to avoid impacts to critical areas and critical area buffers:

A. Avoiding the impact or hazard by not taking a certain action;

B. Minimizing the impact or hazard by:

1. Limiting the degree or magnitude of the action with appropriate technology; or

2. Taking affirmative steps, such as project redesign, relocation or timing;

C. Rectifying the impact to critical areas by repairing, rehabilitating or restoring the affected critical area or its buffer;

D. Minimizing or eliminating the hazard by restoring or stabilizing the hazard area through engineered or other methods;

E. Reducing or eliminating the impact or hazard over time by preservation or maintenance operations during the life of the development proposal or alteration;

F. Compensating for the adverse impact by enhancing critical areas and their buffers or creating substitute critical areas and their buffers; and

G. Monitoring the impact, hazard or success of required mitigation and taking remedial action. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.130 Mitigation and monitoring.

A. If mitigation is required under this chapter to compensate for adverse impacts, unless otherwise provided, an applicant shall:

1. Mitigate adverse impacts to:

a. Critical areas and their buffers; and

b. The development proposal as a result of the proposed alterations on or near the critical areas; and

2. Monitor the performance of any required mitigation.

B. The department shall not approve a development proposal until mitigation and monitoring plans are in place to mitigate for alterations to critical areas and buffers.

C. Whenever mitigation is required, an applicant shall submit a critical area report that includes:

1. An analysis of potential impacts;

2. A mitigation plan that meets the specific mitigation requirements in this chapter for each critical area impacted; and

3. A monitoring plan that includes:

a. A demonstration of compliance with this title;

b. A contingency plan in the event of a failure of mitigation or of unforeseen impacts if:

i. The department determines that failure of the mitigation would result in a significant impact on the critical area or buffer; or

ii. The mitigation involves the creation of a wetland;

c. A monitoring schedule that may extend throughout the impact of the activity or, for hazard areas, for as long as the hazard exists.

D. Mitigation shall not be implemented until after the department approves the mitigation and monitoring plan. The applicant shall notify the department when mitigation is installed and monitoring is commenced, and shall provide the city with reasonable access to the mitigation area for the purpose of inspections during any monitoring period.

E. If monitoring reveals a significant deviation from predicted impact or a failure of mitigation requirements, the applicant shall implement an approved contingency plan. The contingency plan constitutes new mitigation and is subject to all mitigation including a monitoring plan and financial guarantee requirements. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.132 Monitoring program and contingency plan.

A. A monitoring program shall be implemented by the applicant to determine the success of the mitigation project and any necessary corrective actions. This program shall determine if the original goals and objectives are being met.

B. A contingency plan shall be established for correction in the event that the mitigation project is inadequate or fails. A performance and maintenance bond or other acceptable security device is required to ensure the applicant’s compliance with the terms of the mitigation agreement. The bond or other security shall meet the requirements set forth in NMC 18.24.140, Financial guarantee to ensure mitigation, maintenance and monitoring.

C. Monitoring programs prepared to comply with this chapter shall reflect the following guidelines:

1. Use scientific procedures for establishing the success or failure of the project;

2. For vegetation determinations, permanent sampling points shall be established;

3. Vegetative success equals 80 percent per year survival of planted trees and 80 percent cover of shrubs, groundcover, and emergent species, and less than 20 percent cover of invasive species;

4. Submit monitoring reports on the current status of the mitigation project to the department. The reports are to be prepared by a qualified consultant and reviewed by the city, and shall be produced on the following schedule: 30 days after planting, early in the growing season of the second year, end of the growing season of the second year, and annually thereafter;

5. The monitoring reports shall contain the following information on monitoring method and monitoring components, as relevant:

a. Vegetation Monitoring. Methods shall include counts, photo points, random sampling, sampling plots, transects, visual inspections, and/or other means deemed appropriate by the department and a qualified consultant. Vegetation monitoring components shall include general appearance, health, mortality, colonization rates, percent cover, percent survival, volunteer plant species, invasive weeds, and/or other components deemed appropriate by the department and a qualified consultant.

b. Water Quantity Monitoring. Methods shall include piezometers, sampling points, stream gauges, visual observation, and/or other means deemed appropriate by the department and a qualified consultant. Water quantity monitoring components shall include water level, peak flows, soil saturation depth, soil moisture within root zone, inundation, overall water coverage, and/or other components deemed appropriate by the department and a qualified consultant.

c. Water Quality Monitoring. Methods shall include testing, plant indicators, and/or other means deemed appropriate by the department and a qualified consultant. Water quality monitoring components shall include temperature, pH, dissolved oxygen, total suspended solids, total metals, herbicides, pesticides, and/or other components deemed appropriate by the department and a qualified consultant.

d. Wildlife Monitoring. Methods shall include visual sightings, aural observations, nests, scat, tracks, and/or other means deemed appropriate by the department and a qualified consultant. Wildlife monitoring components shall include species counts, species diversity, breeding activity, habitat type, nesting activity, location, usage, and/or other components deemed appropriate by the department and a qualified consultant.

e. Geomorphic Monitoring. Methods shall include cross-sectional surveys, profile surveys, point surveys, photo-monitoring, and/or other means deemed appropriate by the department and a qualified consultant. Monitoring components shall include location and effect of large woody debris, depth and frequency of pools, bank erosion, channel migration, sediment transport/deposition, structural integrity of weirs, and/or other components deemed appropriate by the department and a qualified consultant.

D. Monitoring programs shall meet the following standards:

1. Be established for a minimum of five years;

2. If necessary, correct for failures in the mitigation project;

3. Replace dead or undesirable vegetation with appropriate plantings;

4. Repair damages caused by erosion, settling, or other geomorphological processes to all affected properties and structures, both on and off the property;

5. Redesign mitigation project (if necessary) and implement the new design; and

6. Correction procedures shall be approved by a qualified consultant and the department. (Ord. 2016-538 § 2 (Exh. 3)).

18.24.135 Off-site mitigation.

A. To the maximum extent practical, an applicant shall mitigate adverse impacts to a wetland, aquatic area, wildlife habitat conservation area or wildlife habitat network on or contiguous to the development site. The department may approve mitigation that is off the development site if an applicant demonstrates that:

1. It is not practical to mitigate on or contiguous to the development proposal site; and

2. The off-site mitigation will achieve equivalent or greater hydrological, water quality and wetland or aquatic area habitat functions than the impacted critical area functions.

B. When off-site mitigation is authorized, the department shall give priority to locations within the same drainage subbasin as the development proposal site that meet the following:

1. Public mitigation sites that have been ranked in a process that has been supported by ecological assessments, including wetland and aquatic areas established as priorities for mitigation in the city’s basin plans or other watershed plans.

C. The department may require documentation that the mitigation site has been permanently preserved from future development or alteration that would be inconsistent with the functions of the mitigation. The documentation may include, but is not limited to, a conservation easement or other agreement between the applicant and owner of the mitigation site. The city may enter into agreements or become a party to any easement or other agreement necessary to ensure that the site continues to exist in its mitigated condition.

D. The department may develop a program to allow the payment of a fee in lieu of providing mitigation on a development site. The program should address:

1. When the payment of a fee is allowed considering the availability of a site in geographic proximity with comparable hydrologic and biological functions and potential for future habitat fragmentation and degradation; and

2. The use of the fees for mitigation on public or private sites that have been ranked according to the ecological criteria.

E. The department may allow purchase of credits from a mitigation bank that is approved by the Washington State Department of Ecology, or the King County Wetland Mitigation Reserve Program, as mitigation for impacts on a development site. (Ord. 2020-621 § 3; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.140 Financial guarantee to ensure mitigation, maintenance and monitoring.

A. When mitigation is required pursuant to a development proposal and is not completed prior to the city finally approving the proposal, the city may delay final approval until mitigation is completed or may require the applicant to post a financial guarantee in an amount deemed acceptable to the city. The financial guarantee shall be sufficient to guarantee that all required mitigation measures will be completed no later than the time established by the city in accordance with this chapter.

B. If the development proposal is subject to mitigation, maintenance or monitoring plans, the applicant shall post a financial guarantee in the amount deemed acceptable by the city. The financial guarantee shall be sufficient to guarantee satisfactory workmanship on, materials in and performance of or related to structures and improvements allowed or required by this chapter for a period of five years. The duration of maintenance/monitoring obligations shall be established by the city, based upon the nature of the proposed mitigation, maintenance or monitoring, and the likelihood and expense of correcting mitigation or maintenance failures.

C. A financial guarantee shall also be required for restoration of a critical area or buffer not performed as part of a mitigation or maintenance plan. The financial guarantee shall be in a form and amount deemed acceptable by the city.

D. Depletion, failure or collection of the financial guarantee shall not discharge the obligation of an applicant or violator to complete required mitigation, maintenance, monitoring or restoration.

E. Public development proposals shall be relieved from having to comply with the financial guarantee requirements of this section if public funds have previously been committed for mitigation, maintenance, monitoring or restoration. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.160 Critical area markers and signs.

A. Permanent survey stakes delineating the boundary between adjoining property and critical area tracts shall be set, using iron or concrete markers as established by current survey standards.

B. The boundary between a critical area tract and contiguous land shall be identified with permanent signs.

1. Permanent signs shall be made of a metal face and attached to a metal post, fence, or another material of equal durability.

2. Signs must be posted at an interval of one per lot or every 100 feet, whichever is less, and must be maintained by the property owner in perpetuity.

3. Information regarding critical area sign text and vendors of critical areas signs is on file at the community development department.

C. Critical Area Fencing. In order to inform subsequent purchasers of real property of the location of the critical area buffer boundaries and to discourage encroachment into that buffer, the developer of the property shall install split rail fencing or a similar fencing approved by the community development department along the boundary of the critical area tract.

D. Marking Critical Areas Not Located in Tracts. For those critical areas delineated as part of a building permit application, clearing and grading permit application, or other development application that does not require the creation of a critical area tract, the boundary between a critical area and contiguous land shall be identified with permanent signs.

1. Permanent signs, as approved by the city, shall be made of a metal face and attached to a metal post, fence, or another material of equal durability.

2. No less than two signs shall be posted. Signs must be posted at an interval of one every 50 feet, whichever is less, and must be maintained by the property owner in perpetuity.

3. Information regarding critical area sign text and vendors of critical areas signs is on file at the community development department. (Ord. 2020-621 § 4; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.170 Notice on title.

A. In order to inform subsequent purchasers of real property of the existence of critical areas, the owner of any property containing a critical area or buffer on which a development proposal is submitted shall file a notice approved by the department with the county records and elections division. The required contents and form of the notice shall be set forth in administrative rules. The notice shall inform the public of the presence of the critical area or buffer on the property, of the application of this chapter to the property and that limitations on actions in or affecting the critical area or buffer may exist. The notice shall run with the land. This notice on title shall not be required for a development proposal by a public agency or public or private utility:

1. Within a recorded easement or right-of-way;

2. Where the agency or utility has been adjudicated the right to an easement or right-of-way; or

3. On the site of a permanent public facility.

B. The owner of any property on which a mitigation site is established shall file a notice on title in the same manner as required in subsection (A) of this section. The notice shall inform the public of the presence of the mitigation site on the property, of the application of this chapter to the property and that limitations on actions in or affecting the mitigation site may exist. The notice shall specifically identify the site as a mitigation site. The notice may be combined with any notice required in subsection (A) of this section.

C. The applicant shall submit proof that the notice has been filed for public record before the department approves any development proposal for the property or, in the case of subdivisions, short subdivisions, planned unit developments and binding site plans, at or before recording. For mitigation sites, proof of filing shall be submitted prior to and as a condition of approval of the site for mitigation. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.180 Critical area tracts and designations on site plans.

A. Unless otherwise required in this chapter, critical area tracts shall be used in development proposals for subdivisions, short subdivisions, planned unit developments, binding site plans, and site plan review to delineate and protect those critical areas and buffers listed below:

1. All landslide hazard areas and buffers;

2. All steep slope hazard areas and buffers;

3. All wetlands and buffers;

4. All streams and buffers;

5. Fish and wildlife habitat conservation areas, i.e., waters of the state and lakes; and

6. Unmitigated coal mine hazard areas.

B. Critical area tracts shall not be used for calculation of lot area or other dimensional standards through the subdivision or site plan review process.

C. Critical area tracts shall be recorded on all documents of title of record for all affected lots.

D. Any required critical area tract shall be dedicated to the city or, at the city’s discretion, held in an undivided interest by each owner of a building lot within the development with the ownership interest passing with the ownership of the lot; or shall be held by an incorporated homeowner’s association or other legal entity, such as a land trust, which assures the ownership, maintenance and protection of the tract.

E. Site plans submitted as part of development proposals for building permits and clearing and grading permits shall include and delineate all flood hazard areas mapped by FEMA, King County or the city, landslide and steep slope hazard areas, streams, wetlands, buffers and building setbacks. If only a part of the development proposal site has been mapped pursuant to NMC 18.24.120, the part of the site which has not been mapped shall be clearly identified and labeled on the site plans. The site plans may be attached to the notice on title required by NMC 18.24.170. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2001-247 § 5; Ord. 2000-224 § 1).

18.24.190 Reserved.

(Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2001-248 § 40; Ord. 2000-224 § 1).

18.24.200 Coal mine hazard areas – Classifications.

Based upon a coal mine hazard assessment report prepared pursuant to NMC 18.24.120(B), coal mine hazard areas shall be classified as follows:

A. “Declassified” coal mine areas are those for which a risk of catastrophic collapse is not significant and which the hazard assessment report has determined require no special engineering or architectural recommendations to prevent significant risks of property damage. Declassified coal mine areas may typically include, but are not limited to, areas underlain or directly affected by coal mines at depths greater than 300 feet as measured from the surface but may often include areas underlain or directly affected by coal mines at depths less than 300 feet.

B. “Moderate” coal mine hazard areas are those areas that pose significant risks of property damage which can be mitigated by special engineering or architectural recommendations. Moderate coal mine hazard areas may typically include, but are not to be limited to, areas underlain or directly affected by abandoned coal mine workings from a depth of zero (i.e., the surface of the land) to 300 feet or with overburden-cover-to-seam thickness ratios of less than 10 to one dependent upon the inclination of the seam.

C. “Severe” coal mine hazard areas are those areas that pose a significant risk of catastrophic ground surface collapse. Severe coal mine hazard areas may typically include, but are not to be limited to, areas characterized by unmitigated openings such as entries, portals, adits, mine shafts, air shafts, timber shafts, sinkholes, improperly filled sinkholes, and other areas of past or significant probability for catastrophic ground surface collapse. Severe coal mine hazard areas typically include, but are not limited to, overland surfaces underlain or directly affected by abandoned coal mine workings from a depth of zero (i.e., surface of the land) to 150 feet. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.205 Coal mine hazard areas – Development standards and permitted alterations.

A. Development proposals and other alterations on sites containing coal mine hazard areas shall comply with all applicable requirements set forth in this chapter including, but not limited to, mitigation requirements and the following standards:

1. Alterations within coal mine hazard areas shall not be permitted without prior acceptance of a critical area report containing a coal mine hazard assessment which meets the requirements of NMC 18.24.120(B).

2. The following notice shall be shown on the face of the recorded subdivision, short subdivision, planned unit development or binding site plan for all affected lots or filed with the King County records and elections division as an attachment to the notice on title required pursuant to NMC 18.24.170:

NOTICE

This property is located in an area of historic coal mine activity. A coal mine hazard assessment report has been prepared to characterize the potential hazards contained on this property. The report is dated [insert date of the final report], was prepared by [insert name of professional engineer with license number] at the direction of [insert name of property owner], and reviewed by the City of Newcastle Department of Community Development [and, if necessary, include name of peer reviewing professional engineer with license number]. A review of the report is advised prior to undertaking unregulated or exempt land use activities and is required prior to undertaking regulated land use activities.

B. Permitted alterations to coal mine hazard areas may be allowed pursuant to applicable permits or approvals and subject to mitigation requirements set forth in this chapter, only as follows:

1. Within declassified coal mine areas all alterations are permitted.

2. Within moderate coal mine hazard areas and coal mine byproduct stockpiles, all alterations are permitted when the risk of structural damage is minimized.

3. Within severe coal mine hazard areas the following alterations are permitted:

a. All grading, filling, stockpile removal, and reclamation activities undertaken pursuant to a coal mine hazard assessment report with the intent of eliminating or mitigating threats to human health, public safety, environmental restoration or protection of property if:

i. Signed and stamped plans have been prepared by a professional engineer;

ii. As-built drawings are prepared following reclamation activities; and

iii. The plans and as-built drawings shall be submitted to the department for inclusion with the coal mine hazard assessment report prepared for the property;

b. Private road construction when significant risk of personal injury is eliminated or minimized;

c. Buildings with less than 4,000 square feet of floor area that contain no living quarters and that are not used as places of employment or public assembly when significant risk of personal injury is eliminated or minimized; and

d. Additional land use activities if consistent with recommendations contained within any mitigation plan required by the hazard assessment report. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.207 Coal mine hazard areas – Specific mitigation requirements.

In addition to general mitigation requirements contained in NMC 18.24.130, the following shall apply to mitigation of adverse impacts associated with coal mine hazard areas:

A. Mitigation shall be designed, using appropriate criteria to evaluate the proposed use, to:

1. Minimize risk of structural damage in moderate coal mine hazard areas; and

2. Eliminate or minimize significant risk of personal injury in severe coal mine hazard areas.

Mitigation may include, but is not limited to, incorporation of building setbacks and design and performance tolerances for structures and infrastructure improvements incorporated into site, building or landscape plans; and

B. Any mitigation plan to address potential trough subsidence must be prepared by a professional engineer and may be included in the coal mine hazard assessment report or may be an additional study or report, as appropriate. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5. Formerly 18.24.373).

18.24.208 Coal mine hazard areas – Additional reporting requirements for critical area reports.

Any critical area report for a coal mine hazard area shall include a hazard assessment prepared by a professional engineer using methodology and assumptions consistent with standards or professional engineering guidelines adopted by the department. The report may contain the following as determined by the department to be necessary for the review of the proposed use:

A. A statement of the professional engineer’s qualifications and licensing information, together with a signature and stamped seal;

B. A list of references utilized in preparation of the report;

C. A description of the analytical tools and processes that have been used in the report;

D. Surface exploration data such as borings, drill holes, test pits, wells, geologic reports, geophysical data and other relevant reports or site investigations that may be useful in making conclusions or recommendations about the site under investigation. The locations of subsurface explorations or geophysical profiles completed as part of assessing coal mine hazards shall be located by a professional land surveyor licensed in the state of Washington;

E. A description of historical data and information used in the evaluation, together with sources. Such data and information shall include:

1. Topographic maps at a scale and contour interval of sufficient detail to assess the site. The site boundaries and proposed site development shall be overlain with the mine plan view map, as appropriate;

2. Copies of illustrative coal mine maps showing remnant mine conditions, if available;

3. Aerial photography, as appropriate;

4. Geological data including geologic cross-sections and other illustrative data as appropriate; and

5. Available historic mine records indicating the dates of operation, the date of cessation of active mining, the number of years since abandonment, mining methods, shoring and timbering information, the strength of the overlying rock strata, the extracted seam thickness, the dip or inclination of the strata, workings and surface, the projected surface location of the seam outcrop or subcrop, the estimated depth of the seam outcrop or subcrop, if covered by glacial outwash, glacial till, or other materials at depth, total coal tonnage produced, estimated coal mine byproduct material produced, and the estimated extraction ratio;

F. A mine plan view map, reproduced at the same scale as the topographic map, showing the location of the mine, the extent of mining, the proposed site development, if applicable, and any remnant abandoned mine surface features. The following shall be included:

1. The layout of the underground mine;

2. The location of any mine entries, portals, adits, mine shafts, air shafts, timber shafts, and other significant mine features;

3. The location of any known sinkholes, significant surface depressions, trough subsidence features, coal mine spoil piles and other mine-related surface features;

4. The location of any prior site improvements that have been carried out to mitigate abandoned coal mine features; and

5. Zones showing varying overburden-cover-to-seam thickness ratios, when appropriate;

G. A statement as to the relative degree of accuracy and completeness of the maps and information reviewed, especially regarding historic mine map accuracy, and reasons why such sources are considered reliable for the purpose of the hazard assessment report;

H. A mitigation plan containing recommendations for mitigation, as appropriate, for the specific proposed alteration;

I. Recommendations for additional study, reports, development standards or architectural recommendations for subsequent and more specific proposed alterations, as appropriate;

J. Analysis and recommendations, if any, of the potential for future trough subsidence and special mitigation; and

K. A delineation of coal mine hazard areas for the site under investigation using a map identifying the specific category (i.e., severe, moderate, or declassified) of mine hazard area. For the purposes of obtaining accurate legal descriptions, the mine hazard areas shall be surveyed and the survey map shall be drawn at a scale of not less than one inch equals 200 feet. (Ord. 2016-538 § 2 (Exh. 3)).

18.24.210 Erosion hazard areas – Development standards.

Development proposals and other alterations on sites containing erosion hazard areas shall be allowed, pursuant to applicable permits or approvals, only if they or any other alteration complies with all applicable requirements set forth in this chapter including, but not limited to, mitigation requirements and the following standards:

A. Clearing in an erosion hazard area shall be allowed only from May 1st to September 30th, except that timber harvest may be allowed pursuant to an approved forest practice permit issued by the Washington Department of Natural Resources. See also NMC 17.07.140(N) for additional wet season clearing and grading provisions.

B. All subdivisions, short subdivisions, binding site plans, site plan review and planned unit developments on sites with erosion hazard areas shall retain existing vegetation in all erosion hazard areas until a building permit is approved for development on the lots, except that:

1. Vegetation may be removed as necessary for construction of related infrastructure;

2. Noxious weeds may be removed;

3. Timber may be harvested as allowed in subsection (A) of this section. (Ord. 2021-634 § 5; Ord. 2021-624 § 16; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2001-247 § 6; Ord. 2000-224 § 1).

18.24.215 Erosion hazard areas – Specific mitigation requirements.

In addition to general mitigation requirements contained in NMC 18.24.130, the following shall apply to mitigation of adverse impacts associated with erosion hazard areas:

A. For any development proposal on a site containing an erosion hazard area, an erosion and sediment control plan shall be required and included as part of the mitigation plan. The erosion and sediment control plan shall be prepared in compliance with requirements set forth in the erosion and sediment control standards and the surface water design manual;

B. Damage to or removal of vegetation on lots in a subdivision, short subdivision or binding site plan during construction of related infrastructure shall be mitigated by stabilizing the lots in compliance with the provisions of the erosion and sediment control standards; and

C. If a city determines that erosion from a development proposal site poses a significant risk of damage to downstream receiving waters based on the size of the project, the proximity to the receiving waters or the sensitivity of the receiving waters, the applicant shall monitor the surface water discharge from the site and submit monitoring reports as set forth in an approved mitigation plan. If the project does not meet appropriate water quality standards established by law or administrative rules, the city may suspend further development work on the site until such standards are met. (Ord. 2019-598 § 16; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5, Formerly 18.24.374).

18.24.220 Flood hazard areas – Components.

A. A flood hazard area consists of the following components:

1. Floodplain;

2. Flood fringe;

3. Zero-rise floodway; and

4. Federal Emergency Management Agency (FEMA) floodway.

B. The city shall determine the flood hazard area after obtaining, reviewing and utilizing base flood elevations and available floodway data for a flood having a one percent chance of being equaled or exceeded in any given year, often referred to as the “100-year flood.” The base flood is determined for existing conditions, unless a basin plan including projected flows under future developed conditions has been completed and adopted by the city, in which case these future flow projections shall be used. In areas where the flood insurance study for King County includes detailed base flood calculations, those calculations may be used until projections of future flows are completed and approved by the city. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.230 Flood fringe – Development standards and permitted alterations.

A. Development proposals shall not reduce the effective base flood storage volume of the floodplain. Grading or other activity which would reduce the effective storage volume shall be mitigated by creating compensatory storage on the site or off the site if legal arrangements can be made to assure that the effective compensatory storage volume will be preserved over time. Grading for construction of livestock manure storage facilities to control nonpoint source water pollution designed to the standards of and approved by the King County conservation district is exempt from this compensatory storage requirement.

B. No structure shall be allowed which would be at risk due to stream bank destabilization including, but not limited to, that associated with channel relocation or meandering.

C. All elevated construction shall be designed and certified by a professional structural engineer licensed by the state of Washington and shall be approved by the city prior to construction.

D. Development proposals shall meet the following requirements:

1. New building lots shall contain 5,000 square feet or more of buildable land outside the zero-rise floodway, and building setback areas shall be shown on the face of the plat to restrict permanent structures to this buildable area;

2. All utilities and facilities such as sewer, gas, electrical and water systems shall be located and constructed consistent with subsections (E), (F) and (I) of this section;

3. Base flood data and flood hazard notes shall be shown on the face of the recorded subdivision, short subdivision or binding site plan including, but not limited to, the base flood elevation, required flood protection elevations and the boundaries of the floodplain and the zero-rise floodway, if determined; and

4. The following notice shall also be shown on the face of the recorded subdivision, short subdivision or binding site plan for all affected lots, or filed with the King County records and elections division or an attachment to the notice on title required pursuant to NMC 18.24.170:

NOTICE

Lots and structures located within flood hazard areas may be inaccessible by emergency vehicles during flood events. Residents and property owners should take appropriate advance precautions.

E. New residential structures and substantial improvements of existing residential structures shall meet the following requirements:

1. The lowest floor shall be elevated to one foot above the flood protection elevation;

2. Portions of a structure which are below the lowest floor area shall not be fully enclosed. The areas and rooms below the lowest floor shall be designed to automatically equalize hydrostatic and hydrodynamic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for satisfying this requirement shall meet or exceed the following requirements:

a. A minimum of two openings on opposite walls having a total open area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided;

b. The bottom of all openings shall be no higher than one foot above grade; and

c. Openings may be equipped with screens, louvers or other coverings or devices if they permit the unrestricted entry and exit of floodwaters;

3. Materials and methods which are resistant to and minimize flood damage shall be used; and

4. All electrical, heating, ventilation, plumbing, air conditioning equipment and other utility and service facilities shall be floodproofed to or elevated above the flood protection elevation.

F. New nonresidential structures and substantial improvements of existing nonresidential structures shall meet the following requirements:

1. The elevation requirement for residential structures contained in subsection (E)(1) of this section shall be met; or

2. The structure shall be floodproofed to the flood protection elevation and shall meet the following requirements:

a. The applicant shall provide certification by a professional civil or structural engineer licensed by the state of Washington that the floodproofing methods are adequate to withstand the flood depths, pressures, velocities, impacts, uplift forces and other factors associated with the base flood. After construction, the engineer shall certify that the permitted work conforms with the approved plans and specifications, and

b. Approved building permits for floodproofed nonresidential structures shall contain a statement notifying applicants that flood insurance premiums shall be based upon rates for structures which are one foot below the floodproofed level;

3. Materials and methods which are resistant to and minimize flood damage shall be used; and

4. All electrical, heating, ventilation, plumbing, air conditioning equipment and other utility and service facilities shall be floodproofed to or elevated above the flood protection elevation.

G. All new construction shall be anchored to prevent flotation, collapse or lateral movement of the structure.

H. Mobile homes and mobile home parks shall meet the following requirements:

1. Mobile homes shall meet all requirements for flood hazard protection for residential structures, shall be anchored and shall be installed using methods and practices which minimize flood damage; and

2. No permit or approval for the following shall be granted unless all mobile homes within the mobile home park meet the requirements for flood hazard protection for residential structures:

a. A new mobile home park,

b. An expansion of an existing mobile home park, or

c. Any repair or reconstruction of streets, utilities or pads in an existing mobile home park which equals or exceeds 50 percent of the value of such streets, utilities or pads.

I. Utilities shall meet the following requirements:

1. New and replacement utilities including, but not limited to, sewage treatment facilities shall be floodproofed to or elevated above the flood protection elevation;

2. New on-site sewage disposal systems shall be, to the extent possible, located outside the limits of the base flood elevation. The installation of new on-site sewage disposal systems in the flood fringe may be allowed if no feasible alternative site is available;

3. Sewage and agricultural waste storage facilities shall be floodproofed to the flood protection elevation;

4. Aboveground utility transmission lines, other than electric transmission lines, shall only be allowed for the transport of nonhazardous substances; and

5. Buried utility transmission lines transporting hazardous substances shall be buried at a minimum depth of four feet below the maximum depth of scour for the base flood, as predicted by a professional civil engineer licensed by the state of Washington, and shall achieve sufficient negative buoyancy so that any potential for flotation or upward migration is eliminated.

J. Critical facilities may be allowed within the flood fringe of the floodplain, but only when no feasible alternative site is available. Critical facilities shall be evaluated through the conditional or special use permit process. Critical facilities constructed within the flood fringe shall have the lowest floor elevated to three or more feet above the base flood elevation. Floodproofing and sealing measures shall be taken to ensure that hazardous substances will not be displaced by or released into floodwaters. Access routes elevated to or above the base flood elevation shall be provided to all critical facilities from the nearest maintained public street or roadway.

K. Prior to approving any permit for alterations in the flood fringe, the city shall determine that all permits required by state or federal law have been obtained. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.240 Zero-rise floodway – Development standards and permitted alterations.

A. The requirements which apply to the flood fringe shall also apply to the zero-rise floodway. The more restrictive requirements shall apply where there is a conflict.

B. A development proposal including, but not limited to, new or reconstructed structures shall not cause any increase in the base flood elevation unless the following requirements are met:

1. Amendments to the Flood Insurance Rate Map are adopted by FEMA, in accordance with 44 CFR 70, to incorporate the increase in the base flood elevation; and

2. Appropriate legal documents are prepared in which all property owners affected by the increased flood elevations consent to the impacts on their property. These documents shall be filed with the title of record for the affected properties.

C. The following are presumed to produce no increase in base flood elevation and shall not require a special study to establish this fact:

1. New residential structures outside the FEMA floodway on lots in existence before the date of incorporation which contain less than 5,000 square feet of buildable land outside the zero-rise floodway and which have a total building footprint of all proposed structures on the lot of less than 2,000 square feet;

2. Substantial improvements of existing residential structures in the zero-rise floodway, but outside the FEMA floodway, where the footprint is not increased; or

3. Substantial improvements of existing residential structures meeting the requirements for new residential structures in NMC 18.24.230.

D. Post or piling construction techniques which permit water flow beneath a structure shall be used.

E. All temporary structures or substances hazardous to public health, safety and welfare, except for hazardous household substances or consumer products containing hazardous substances, shall be removed from the zero-rise floodway during the flood season from September 30th to May 1st.

F. New residential or nonresidential structures shall meet the following requirements:

1. The structures shall be outside the FEMA floodway; and

2. The structures shall be on lots in existence before the date of incorporation which contain less than 5,000 square feet of buildable land outside the zero-rise floodway.

G. Utilities may be allowed within the zero-rise floodway if the city determines that no feasible alternative site is available, subject to the following requirements:

1. Installation of new on-site sewage disposal systems shall be prohibited unless a waiver is granted by the King County department of public health; and

2. Construction of sewage treatment facilities shall be prohibited.

H. Critical facilities shall not be allowed within the zero-rise floodway except as provided in subsection (J) of this section.

I. Livestock manure storage facilities and associated nonpoint source water pollution facilities designed, constructed and maintained to the standards of and approved in a conservation plan by the King County conservation district may be allowed if the city reviews and approves the location and design of the facilities.

J. Structures and installations which are dependent upon the floodway may be located in the floodway if the development proposal is approved by all agencies with jurisdiction. Such structures include, but are not limited to:

1. Dams or diversions for water supply, flood control, hydroelectric production, irrigation or fisheries enhancement;

2. Flood damage reduction facilities, such as levees and pumping stations;

3. Stream bank stabilization structures where no feasible alternative exists for protecting public or private property;

4. Stormwater conveyance facilities subject to the development standards for streams and wetlands and the surface water design manual;

5. Boat launches and related recreation structures;

6. Bridge piers and abutments; and

7. Other fisheries enhancement or stream restoration projects. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.250 FEMA floodway – Development standards and permitted alterations.

A. In addition to subsections (B) and (C) of this section, Chapter 14.25 NMC applies to the FEMA floodway. The more restrictive requirements shall apply where there is a conflict.

B. A development proposal including, but not limited to, new or reconstructed structures shall not cause any increase in the base flood elevation.

C. New residential structures are prohibited within the FEMA floodway. (Ord. 2021-632 § 4; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.260 Flood hazard areas – Certification by engineer or surveyor.

A. For all new structures or substantial improvements in a flood hazard area, the applicant shall provide certification by a professional civil engineer or land surveyor licensed by the state of Washington of:

1. The actual as-built elevation of the lowest floor, including basement; and

2. The actual as-built elevation to which the structure is floodproofed, if applicable.

B. The engineer or surveyor shall indicate if the structure has a basement.

C. The city shall maintain the certifications required by this section for public inspection. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.270 Landslide hazard areas – Development standards and permitted alterations.

A. Development proposals and other alterations on sites containing landslide hazard areas or buffers shall comply with all applicable requirements set forth in this chapter, including, but not limited to, mitigation requirements and the following standards:

1. A buffer shall be established from all edges of the landslide hazard area. The size of the buffer shall be determined by the department to eliminate or minimize the risk of property damage, death or injury resulting from landslides caused in whole or part by the development, based upon the department’s review of and concurrence with a critical area report prepared by a geotechnical engineer or geologist. If no critical area report is submitted to the department, the minimum buffer shall be 50 feet;

2. Unless otherwise provided or as a necessary part of an approved alteration, removal of any vegetation from a landslide hazard area or buffer shall be prohibited;

3. All alterations shall be undertaken in a manner to minimize disturbance to the landslide hazard area, slope and vegetation unless necessary for slope stabilization.

B. Alterations to landslide hazard areas and buffers may be allowed, pursuant to applicable permits or approvals and subject to mitigation requirements set forth in this chapter, only as follows:

1. Surface water conveyances if the department finds that:

a. Discharging the surface water at the base of the landslide hazard area has less adverse impact upon the critical area than if the surface water were dispersed at the top of the landslide hazard area; and

b. Adverse impacts to fish are minimized, to the maximum extent possible, by maintaining the prealteration groundwater volume to support fish habitat in receiving water bodies;

2. Public and private utilities and utility corridors if the applicant shows that:

a. The alterations involved will not subject the critical area to an increased risk of landslide or erosion; and

b. Vegetation removal is limited to the minimum necessary to locate the utility or construct the corridor;

3. Normal and routine maintenance of existing public and private utility facilities and utility corridors if the applicant shows that:

a. The alterations involved will not subject the critical area to an increased risk of landslide or erosion; and

b. Vegetation removal for the purpose of utility and corridor maintenance is the minimum necessary to maintain the utility’s function;

4. Vegetation removal activities, as follows:

a. The removal of noxious weeds;

b. The removal of vegetation, only as necessary for surveying purposes; and

c. The removal of hazard trees, as determined by the department;

5. Stabilization of sites where erosion or landsliding threatens public or private structures, utilities, roadways, driveways or publicly maintained trails or where erosion or landsliding threatens any lake, stream, wetland or shoreline. Stabilization work shall be performed in a manner which causes the least possible disturbance to the slope and its vegetative cover;

6. Exploratory drilling and testing, involving only necessary and limited clearing and grading, for the purpose of preparing critical area reports;

7. The application of herbicides or other hazardous substances, if necessary, as approved by the department; and

8. Any alterations in a landslide hazard area located in an area that does not meet the criteria as a steep slope as defined under NMC 18.06.628 only if:

a. The development proposal will not decrease slope stability on contiguous properties; and

b. Mitigation based on the best available engineering and geological practices is implemented which either eliminates or minimizes the risk of property damage, death or injury resulting from landsliding. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.280 Seismic hazard areas – Development standards.

Development proposals and other alterations on sites containing seismic hazard areas shall be allowed, pursuant to applicable permits or approvals, only if they or any other alteration complies with all applicable requirements set forth in this chapter including, but not limited to, mitigation requirements and the following standards:

A. Development proposals shall satisfy the foundation standards of the building code as adopted by the city, not including the building code’s exceptions to those standards; and

B. The following shall be exempt from the provisions of this section and mitigation requirements:

1. Buildings with less than 2,500 square feet of floor area or roof area, whichever is greater, and which are not residential structures or used as places of employment or public assembly;

2. Additions, less than 250 square feet, to single-story residences; and

3. Fences. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.290 Reserved.

(Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1).

18.24.300 Steep slope hazard areas – Development standards and permitted alterations.

A. Development proposals and other alterations on sites containing steep slope hazard areas or buffers shall comply with all applicable requirements set forth in this chapter including, but not limited to, mitigation requirements and the following standards:

1. A buffer shall be established from all edges of the steep slope hazard area. The size of the buffer or setback shall be determined by the department to eliminate or minimize the risk of property damage, death or injury resulting from slope instability, landsliding or erosion caused in whole or part by the development, based upon the department’s review of and concurrence with a critical area report prepared by a geotechnical engineer or geologist. In no instance shall the minimum buffer be less than 10 feet. If no critical area report is submitted to the department, the minimum buffer shall be 50 feet; and

2. Buffers for steep slope hazard areas shall not be subject to provisions for buffer averaging; and

3. Unless otherwise provided or as a necessary part of an approved alteration, removal of any vegetation from a steep slope hazard area or buffer shall be prohibited.

B. Alterations to steep slope hazard areas and buffers may be allowed pursuant to applicable permits or approvals and subject to mitigation requirements set forth in this chapter, only as follows:

1. Surface water conveyances if the department finds that:

a. The conveyance is installed in a manner to minimize disturbance to the slope and vegetation;

b. Discharging the surface water at the base of the steep slope hazard area has less adverse impact upon the critical area than if the surface water were dispersed at the top of the slope; and

c. Adverse impacts to fish are minimized, to the maximum extent possible, by maintaining the prealteration groundwater volume to support fish habitat in receiving water bodies;

2. Public and private trails as long as no trails are constructed of impervious surfaces which will contribute to surface water runoff, unless such construction is necessary for soil stabilization or soil erosion prevention or unless the trail system is specifically designed and intended to be accessible to handicapped persons. Trail construction shall be in compliance with adopted trail standards;

3. Public and private utilities and utility corridors if the applicant shows that:

a. The alterations involved will not subject the critical area to an increased risk of landslide or erosion; and

b. Vegetation removal is limited to the minimum necessary to locate the utility or construct the corridor;

4. Normal and routine maintenance of existing public and private utility facilities and utility corridors if the applicant shows that:

a. The alterations involved will not subject the critical area to an increased risk of landslide or erosion; and

b. Vegetation removal for the purpose of utility and corridor maintenance is the minimum necessary to maintain the utility’s function;

5. Vegetation removal activities, as follows:

a. The removal of noxious weeds;

b. The removal of vegetation, only as necessary for surveying purposes; and

c. The removal of hazard trees, as determined by the city;

6. Stabilization of sites where erosion or landsliding threatens preexisting public or private structures, utilities, roadways, driveways or trails or where erosion or landsliding threatens any lake, stream, wetland or shoreline. Stabilization work shall be performed in a manner which causes the least possible disturbance to the slope and its vegetative cover;

7. Point discharges from surface water facilities onto or upstream from steep slope hazard areas that are also erosion hazard areas shall be prohibited except as follows:

a. Conveyed via continuous storm pipe downslope to a point where there are no erosion hazard areas downstream from the discharge;

b. Discharged at flow durations matching predeveloped conditions, with adequate energy dissipation, into existing channels that previously conveyed stormwater runoff in the predeveloped state;

c. Dispersed discharge upslope of the steep slope onto a low-gradient undisturbed buffer demonstrated to be adequate to infiltrate all surface and stormwater runoff;

8. Exploratory drilling and testing, involving only necessary and limited clearing and grading, for the purpose of preparing critical area reports; and

9. The application of herbicides or other hazardous substances, if necessary, as approved by the department.

C. At least one of the following must be true for slopes to be exempt from provisions of this section:

1. Altering slopes which are 40 percent or steeper with a vertical elevation change of up to 20 feet if no adverse impact will result from the exemption based on the department’s review of and concurrence with a critical area report; or

2. Regrading and stabilizing a slope formed as a result of a legal grading activity.

In either case, if the resulting slope still meets the criteria for a steep slope, it shall be subject to all requirements applicable to steep slopes. (Ord. 2022-645 § 11; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.302 Fish and wildlife habitat conservation areas.

A. Designation. Fish and wildlife habitat conservation areas are those areas essential for the preservation of critical habitats and species. All areas within the city of Newcastle meeting one or more of the following criteria are designated fish and wildlife habitat conservation areas:

1. Areas with Which State or Federally Designated Endangered, Threatened, and Sensitive Species Have a Primary Association.

a. Federally designated endangered and threatened species are those fish and wildlife species identified by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service that are in danger of extinction or threatened to become endangered. The U.S. Fish and Wildlife Service and the National Marine Fisheries Service should be consulted for current listing status.

b. State designated endangered, threatened, and sensitive species are those fish and wildlife species native to the state of Washington identified by the Washington Department of Fish and Wildlife, that are 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. State designated endangered, threatened, and sensitive species are periodically recorded in WAC 232-12-014 (state endangered species) and 232-12-011 (state threatened and sensitive species). The State Department of Fish and Wildlife maintains the most current listing and should be consulted for current listing status.

2. State Priority Habitats and Areas Associated with State Priority Species. Priority habitats and species are considered to be priorities for conservation and management. Priority species require protective measures for their perpetuation due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. Priority habitats are those habitat types or elements with unique or significant value to a diverse assemblage of species. A priority habitat may consist of a unique vegetation type or dominant plant species, a described successional stage, or a specific structural element. Priority habitat and species are identified by the State Department of Fish and Wildlife.

3. State-Designated Priority Habitat or Critical Habitat for State-Designated Species. The Washington Department of Fish and Wildlife should be consulted for the current lists of priority habitats and species.

4. Habitats and Species of Local Importance. Habitats and species of local importance are those identified by the city, including but not limited to those habitats and species that, due to their population status or sensitivity to habitat manipulation, warrant protection.

5. Naturally Occurring Ponds under 20 Acres. Naturally occurring ponds are those ponds under 20 acres and their submerged aquatic beds that provide fish and wildlife habitat, including those artificial ponds intentionally created from dry areas in order to mitigate impacts to ponds. Naturally occurring ponds do not include ponds deliberately designed and created from dry sites, such as canals, detention facilities, wastewater treatment facilities, farm ponds, temporary construction ponds, and landscape amenities, unless such artificial ponds were intentionally created for mitigation.

6. Waters of the State. Waters of the state include 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.

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

8. Land useful or essential for preserving connections between habitat blocks and open spaces. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.304 Fish and wildlife habitat conservation areas – Additional requirements for critical area reports.

The critical area report shall contain the information listed in NMC 18.24.120, Contents of critical area report – General requirements; and an assessment of habitats and potential for priority species, including the following site and proposal related information at a minimum:

A. Fish and Wildlife Habitat Report Requirements.

1. Preparation by a Qualified Professional. A critical areas report for a fish and wildlife habitat conservation area shall be prepared by a qualified professional who is a biologist with experience preparing reports for the relevant type of habitat.

2. Areas Addressed in Critical Area Report. The following areas shall be addressed in a critical area report for fish and wildlife habitat conservation areas:

a. The project area of the proposed activity;

b. All fish and wildlife habitat conservation areas and recommended buffers within 300 feet of the project area; and

c. All floodplains, other critical areas, and related buffers within 300 feet of the project area.

3. Identification of any species of local importance, priority species, or endangered, threatened, sensitive or candidate species that have a primary association with habitat on or adjacent to the project area, and assessment of potential project impacts to the use of the site by the species;

4. A discussion of any federal, state, or local special management recommendations, including Washington Department of Fish and Wildlife habitat management recommendations, that have been developed for species or habitats located on or adjacent to the project area;

5. A discussion of any ongoing management practices that will protect habitat after the project site has been developed, including any proposed monitoring, maintenance, and adaptive management programs;

6. When appropriate, due to the type of habitat or species present or the project condition, the city may also require the habitat management plan to include an evaluation by the Washington Department of Fish and Wildlife or other qualified expert regarding the applicant’s analysis and the effectiveness of any proposed mitigating measure or programs, to include any recommendations as appropriate;

7. A detailed discussion of the direct and indirect potential impacts on habitat by the project, including potential impacts to water quality or other critical areas that provide habitat functions (e.g., wetlands or forested slopes);

8. A discussion of measures, including avoidance, minimization, and mitigation, proposed to preserve existing habitats and restore any habitat that was degraded prior to the current proposed land use activity and to be conducted in accordance with mitigation sequencing (Avoiding impacts to critical areas, NMC 18.24.125); and

9. A discussion of ongoing management practices that will protect habitat after the project site has been developed, including proposed monitoring and maintenance programs.

B. Stream Reporting Requirements.

1. A stream reconnaissance report shall be prepared by a qualified stream biologist or stream ecologist. The report will also be used by the city to establish appropriate buffer requirements. The information required for this report should be coordinated with the study and reporting requirements established for any other critical areas located on the site.

a. The ordinary high water mark shall be flagged in the field by a qualified consultant. Field flagging must be distinguishable from other survey flagging on the site. The field flagging must be accompanied by a stream reconnaissance report.

b. The report shall include the following information:

i. Streams Map. Stream ordinary high water marks (OHWMs) shall be located on a site map with an engineering scale of one inch equals 20 feet. The map must show:

(A) Surveyed locations of all stream OHWMs on the property;

(B) Hydrologic mapping showing patterns of water movement into, through, and out of the site area.

ii. Stream Reconnaissance Report. A written stream reconnaissance report which includes the following information:

(A) A stream assessment. This assessment shall describe specific descriptions of streams, including stream classification, gradient and flow characteristics, stream bed condition, stream bank and slope stability, presence of fish or habitat for fish, presence of obstruction to fish movement, general water quality, stream bank vegetation, and stream buffer requirements.

(B) A characterization of the riparian corridor. This characterization shall include analysis of the stream buffer to provide the following key functions: shade and temperature regulation, flood conveyance, water quality protection and pollutant removal, nutrient cycling, sediment transport, bank stabilization, woody debris recruitment, wildlife habitat, and microclimate control.

(C) A summary of existing stream value for fisheries habitat, including special consideration for anadromous fisheries. This shall include a discussion on the stream’s potential for fish use. Parameters to be analyzed include, but are not limited to, distance of bankfull width, channel gradient, size of contributing upstream areas, and fish passage obstructions, if any.

(D) A discussion of measures including avoidance, minimization, and mitigation to preserve the existing riparian corridor and restore areas that were degraded prior to the current proposed land use activity. This shall include a summary of proposed stream and buffer alterations, impacts, and the need for the alterations as proposed. If alteration of a stream is proposed, a stream mitigation plan is required according to the standards of NMC 18.24.309, Specific mitigation requirements – Streams. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.305 Fish and wildlife habitat conservation areas – Development standards.

A. Habitat Conservation Buffers.

1. The city shall require the establishment of buffer areas for activities in, or adjacent to, fish and wildlife habitat conservation areas when needed to protect fish and wildlife habitat conservation areas based on a critical area report.

2. When a species is more susceptible to adverse impacts during specific periods of the year, seasonal restrictions may apply. Activities may be further restricted and buffers may be increased during the specified season.

B. General Requirements.

1. A fish and wildlife habitat conservation area and associated buffer may be altered only if the proposed alteration of the habitat and associated buffer does not degrade the function of the habitat and associated buffer.

2. Whenever activities are proposed in or adjacent to a habitat conservation area or associated buffer, such area shall be protected through the application of measures in accordance with a critical area report prepared by a qualified professional and approved by the city of Newcastle, and guidance provided by the appropriate state or federal agencies.

3. The city shall condition approvals of activities allowed within or adjacent to a habitat conservation area or its buffer, as necessary to minimize or mitigate any potential adverse impacts. Conditions may include, but are not limited to, the following:

a. Establishment of buffer zones;

b. Preservation of critical important vegetation;

c. Limitation of public access to the habitat, including fencing to deter unauthorized access;

d. Seasonal restriction activities;

e. Establishment of a duration and timetable for periodic review of mitigation activities;

f. Requirement of a performance financial guarantee, to ensure completion and success of proposed mitigation.

4. Mitigation of alterations to habitat conservation areas shall achieve equivalent or greater biological functions. Mitigation shall address each function affected by the alteration to achieve functional equivalency or improvement on a per function basis. Mitigation shall be detailed in a fish and wildlife habitat conservation area mitigation plan, which may include the following as necessary:

a. A native vegetation plan;

b. Plans for retention, enhancement or restoration of specific habitat features;

c. Plans for control of nonnative invasive plant or wildlife species; and

d. Stipulations for use of innovative, sustainable building practices. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1. Formerly 18.24.306).

18.24.306 Streams – Classifications.

A. Streams shall be classified as follows pursuant to WAC 222-16-030 or as amended:

1. Type S streams, only including streams inventoried as “shorelines of the state” under the city of Newcastle’s shoreline master program pursuant to Chapter 90.58 RCW;

2. Type F streams include segments of natural waters other than Type S waters, which are within the bankfull widths of defined channels and periodically inundated areas of their associated wetlands, or within lakes, ponds, or impoundments having a surface area of one-half acre or greater at seasonal low water and which in any case contain fish habitat;

3. Type Np streams, only including streams which are intermittent or ephemeral during years of normal rainfall and are not used by fish. Type Np streams include all segments of natural waters within the bankfull width of defined channels that are perennial non-fish habitat streams; and

4. Type Ns streams include segments of natural waters within the bankfull width of the defined channels that are not Type S, F, or Np waters. They are seasonal, non-fish habitat streams in which surface flow is not present for at least some portion of a year of normal rainfall and are not located downstream from any stream reach that is a Type Np water. Ns streams must be physically connected by an above-ground channel system to Type S, F, or Np waters.

B. For purposes of the above stream classifications, normal rainfall shall mean rainfall that is at or within 10 percent of the mean of the accumulated annual rainfall record, based upon the water year for King County (October 1st through September 30th) as recorded at the Seattle-Tacoma International Airport or the official rain gauge operated by a governmental agency nearest to the site. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2001-248 § 41; Ord. 2000-224 § 1. Formerly 18.24.340).

18.24.307 Streams – Development standards.

Development proposals and other alterations on sites containing streams or buffers shall comply with the following standards:

A. The following minimum buffers shall be established from the ordinary high water mark or from the top of the bank if the ordinary high water mark cannot be identified:

1. Type S stream shall have a 200-foot buffer;

2. Type F stream containing fish habitat shall have a 100-foot buffer;

3. Type Np stream not used by fish habitat shall have a 50-foot buffer;

4. Type Ns streams shall have a 25-foot buffer;

5. Any stream which is subject to a change of classification due to restoration, relocation, or enhancement shall have the minimum buffer required for the highest stream class involved;

6. Any stream with an ordinary high water mark within 25 feet of the toe of a slope 30 percent or greater and with a buffer which extends onto the slope shall have the minimum buffer required for the stream class involved plus 25 feet from the top of the 30 percent slope, unless the minimum buffer for the stream class extends more than 25 feet beyond the top of the slope. These stream buffers associated with slopes 30 percent or greater shall not be subject to buffer averaging provisions; and

7. Any stream adjoined by a riparian wetland or other contiguous critical area shall have the buffer required for the stream class involved or the buffer which applies to the wetland or other critical area, whichever is greater.

B. The minimum buffers may be reduced where an existing roadway or driveway which complied with law at the time it was built transects the buffer of a stream, and an applicant demonstrates to the department that the part of the buffer sought to be reduced on the side of the alteration farthest from the critical area does not provide additional protection to the proposed development or the critical area does not perform any biological, geological, or hydrological buffer functions.

C. Buffer width averaging may be allowed by the city if:

1. It will provide equivalent or increase the stream and associated buffer functions;

2. It will not adversely affect fish habitat;

3. It will provide additional natural resource protection; and

4. The total area contained in the buffer of each stream on the development proposal site is not decreased and at no point is the width of the buffer reduced by more than 25 percent.

D. Buffers may be increased, as follows:

1. A buffer may be increased as required by the city if the city determines that the standard buffer is insufficient to prevent stream degradation and to protect the hydrologic and biologic functions of the stream or any of the following unique stream features. The buffer may be increased up to 300 feet unless larger buffers are needed to protect federal- or state-listed threatened, endangered, priority or candidate priority wildlife species based on Washington Department of Fish and Wildlife priority habitats and species management recommendations, state or federal studies or best available scientific information. Unique stream features which may be protected by increased buffers include:

a. Documented occurrences of federal- or state-listed threatened, endangered, priority or candidate priority wildlife species found in the stream or its buffer, including races or species of fish, spawning or breeding sites, colonial or communal roosts, areas of regular concentration or species confined to a stream habitat;

b. The presence of fish of local importance including, but not limited to, fish of importance to and subject to the treaty rights of a federally recognized tribe;

c. Herons or raptors of local importance supported by the stream or habitat it provides;

d. A stream channel which, at the ordinary high water mark, is at least five feet wide, and the channel and buffer are of pristine or near-pristine quality, as evidenced by the following:

i. There are no human-caused changes to topography or hydrology such as clearing, grading, filling, logging, dredging, diking or the presence of culverts or ditches;

ii. There are fewer than five percent nonnative plants which appear to be invading; and

iii. There is little or no human-caused degradation of the water quality of the stream or stream system; and

e. The stream is within a locally or regionally significant resource area designated in an adopted basin plan;

2. A buffer may be increased as required by the city if the city determines that the standard buffer is insufficient to protect the stream from hazardous substances, landslide, erosion or steep slope hazards and adverse impacts from trail, road, driveway, or utility corridors. The determination to increase the buffer and the determination as to the size of buffer shall be based upon the following:

a. The stream type;

b. The severity of the hazard to or adverse impacts upon the stream; and

c. The proximity of the hazard, trail, road, driveway, or utility corridor.

E. Unless otherwise provided or as a necessary part of an approved alteration, removal of any vegetation or woody debris from a stream or buffer shall be prohibited.

F. There shall be no introduction of any plant or wildlife which is not indigenous to the Puget Sound region into any stream or buffer unless authorized by a state or federal permit or approval. (Ord. 2022-645 § 11; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2001-248 § 42; Ord. 2000-224 § 1. Formerly 18.24.350).

18.24.308 Streams – Permitted alterations.

If the department determines that there is no practical alternative location with less adverse impact on the stream or its buffer, then alterations to streams and buffers may be allowed pursuant to applicable permits or approvals and subject to mitigation requirements set forth in this chapter, as follows:

A. Public and private utility corridors in stream buffers if:

1. The utility corridor is not located in a buffer where the buffer or associated stream is used by species listed as endangered or threatened by the state or federal government or contains critical or outstanding actual habitat for those species or heron rookeries or raptor nesting trees;

2. The construction area and resulting utility corridor are the minimum widths practical;

3. Except as provided in subsection (E) of this section, the utility corridor is located within the outer 25 percent of the buffer or within a roadway, the improved area of an existing utility corridor or the improved area of an approved trail;

4. The stream and its buffer are protected during utility corridor construction and maintenance;

5. The utility corridor is aligned to avoid cutting significant trees, to the maximum extent practical;

6. Vegetation removal is limited to the minimum necessary to construct the corridor;

7. Vegetation removal for the purpose of corridor maintenance is the minimum necessary to maintain the utility’s function;

8. Any corridor access for maintenance is at specific points into the buffer rather than by a parallel road, to the maximum extent practical;

9. If the department determines that a parallel maintenance road is necessary, the following conditions shall be complied with:

a. The width of the roadway shall be as small as possible and not greater than 15 feet; and

b. The location of the roadway shall be contiguous to the utility corridor on the side farthest from the stream;

10. Additional requirements for sewer utility and public water distribution corridors are complied with, as follows:

a. If the sewer utility or public water distribution corridor cannot be located in the outer 25 percent of the buffer due to gravity flow requirements, it may be located in another part of the buffer with less adverse impact to the stream;

b. An additional, contiguous and undisturbed buffer, equal in width to that part of the proposed sewer utility or public water distribution corridor located in the original stream buffer including any allowed maintenance roads, is provided to protect the stream;

11. All unavoidable impacts are fully mitigated;

B. Joint use of an approved utility corridor by other utilities;

C. Surface water conveyance or discharge in the buffer if the department finds that:

1. The discharge does not:

a. Increase the rate of flow above the predevelopment rate;

b. Decrease the water quality of the stream;

c. Decrease the quality of fish spawning and rearing areas; and

2. Conveying the surface water through the buffer and discharging at the stream edge has less adverse impact upon the critical area or buffer than if the surface water were discharged at the buffer’s edge and allowed to naturally drain through the buffer;

D. Except as provided in subsection (E) of this section, public and private trails in stream buffers in compliance with requirements set forth in administrative rules and with the following:

1. The trail surface shall not be made of impervious materials, except that public multipurpose trails may be made of impervious materials if they meet all other requirements including water quality standards set forth in Chapter 13.05 NMC;

2. Buffers shall be expanded, where possible, equal to the width of the trail corridor including disturbed areas;

E. Stream and buffer crossings if:

1. The department determines that there is no feasible alternative location outside the critical area with less adverse impact on the stream or its buffer;

2. The crossing uses bridges or other construction techniques which do not disturb the stream bed or bank, except that bottomless culverts or other appropriate methods demonstrated to provide fish passage may be used for Type F, Np or Ns if the applicant demonstrates that such methods and their implementation will pose no harm to the stream or inhibit migration of fish;

3. The crossing is constructed during the summer low flow period and is timed to avoid stream disturbance during periods when critical to fish habitat;

4. The crossing is located where it has the least adverse impact on the stream and buffer which generally will be the shortest distance across the stream or its buffer;

5. The crossing is not located over or through a fish spawning area unless the city determines that no other possible crossing site exists;

6. Trail crossings shall comply with all applicable requirements for trails set forth in subsection (D) of this section;

7. Bridge piers or abutments are not placed within the FEMA floodway or the ordinary high water mark;

8. The crossing does not diminish the flood-carrying capacity of the stream;

9. Vegetation removal is limited to the minimum necessary to construct the crossing;

10. Vegetation removal for the purpose of the crossing’s maintenance is the minimum necessary to maintain the utility’s function;

11. Additional requirements for underground utility crossings are complied with, as follows:

a. The construction corridor and resulting utility corridor shall be the minimum widths possible;

b. The crossing shall be laterally drilled and located at a depth of at least four feet below the maximum depth of scour for the base flood predicted by a civil engineer except that temporary bore pits to construct such crossing may be permitted within the buffer, and a crossing of a Type Ns stream may be made with cuts when the stream is dry; and

c. Utility crossings shall comply with all applicable requirements for utility corridors set forth in subsection (A) of this section; and

12. Crossings are minimized and serve multiple purposes and properties whenever possible;

F. Stream relocations only for Type Ns streams for the purpose of enhancing resources in the stream including, but not limited to, wildlife habitat or water quality if:

1. Appropriate floodplain protection measures are used; and

2. The relocation occurs on the site, except that relocation off the site may be allowed if the applicant:

a. Demonstrates that any on-site relocation is impractical;

b. Provides all necessary easements and waivers from affected property owners and acknowledges they are responsible for obtaining all required approvals before beginning work; and

c. Demonstrates that the off-site location is in the same drainage subbasin as the original stream; and

3. The applicant demonstrates, based on information provided by a civil engineer and a stream scientist, that:

a. The equivalent base flood storage volume and function will be maintained;

b. There will be no adverse impact to local groundwater;

c. There will be no increase in velocity;

d. There will be no interbasin transfer of water;

e. There will be no increase in the sediment load;

f. The relocation conforms to all applicable laws; and

g. All work is carried out under the direct supervision of a stream scientist;

G. Stabilization of a stream channel:

1. Pursuant to the stream bank stabilization standards of NMC 18.24.220 through 18.24.260, flood hazard areas;

2. Done in a manner which minimizes or avoids any adverse impact to fish habitat and is limited to only that necessary to eliminate the specific threat. Stream bank stabilization projects shall use bioengineering to the maximum extent possible; and

3. If the department determines that stream channel stabilization is necessary to protect unique natural resources or fish habitat;

H. Stream enhancement or restoration which is not mitigation, if accomplished according to a plan for its design, implementation, maintenance and monitoring. The city may require that the plan be prepared by a civil engineer and a stream scientist and be carried out under the direction of a stream scientist. Restoration or enhancement shall be approved only if it results in a net improvement to the functions of the stream system and if it is in compliance with stream restoration standards set forth in NMC 18.24.309;

I. Maintenance and enhancement of roadside and agricultural ditches which are used by fish;

J. The following vegetation removal activities:

1. Where not exempt, the removal of noxious weeds from streams and their buffers;

2. The removal of the following vegetation from streams and their buffers with hand labor and light equipment:

a. Himalayan blackberry (Rubus discolor, R. procerus);

b. Evergreen blackberry (Rubus laciniatus);

3. The removal of vegetation from stream buffers, only as necessary, for surveying purposes; and

4. The removal of hazard trees from streams and buffers, as determined by the department;

K. Reconstruction, remodeling or replacement of an existing structure upon another portion of an existing impervious surface which was established pursuant to law if:

1. Within the buffer, the structure is located no closer to the stream than the existing structure; and

2. The existing impervious surface within the buffer or stream is not expanded as a result of the reconstruction, remodeling or replacement;

L. High flow bypass tightlines to protect the stream from erosion if there is no practical alternative and the following standards are complied with:

1. The tightline shall be routed outside the stream buffer except to reach the inlet from and outlet to the tightline;

2. An energy dissipater shall be located outside the active stream channel and the ordinary high water mark and designed so that the bypassed water reenters the stream with minimum adverse impact. The department may require that a side channel be used which provides high flow refuge if fish are present;

3. The design shall maintain predevelopment flows;

4. The channel shall be stabilized, as required by the department, with woody debris and native vegetation, bioengineering or other similar techniques;

5. An adjustable flow splitter shall be located at the inlet to the tightline, and flows shall be adjusted to maintain the stream’s biological functions; and

6. A maintenance plan, approved by the department, shall be required to ensure the maintenance of flow and the continued operation of the high flow bypass tightline;

M. Exploratory drilling and testing, involving only necessary and limited clearing and grading, for the purpose of preparing critical area reports; and

N. The application of herbicides, pesticides, organic or mineral-derived fertilizers, or other hazardous substances, if necessary, as approved by the department. (Ord. 2022-645 § 11; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1. Formerly 18.24.360).

18.24.309 Specific mitigation requirements – Streams.

In addition to general mitigation requirements contained in this chapter, the following shall apply to mitigation of adverse impacts associated with streams:

A. Mitigation of alterations to streams or their buffers shall achieve equivalent or greater biologic functions including, but not limited to, habitat functions and equivalent or greater hydrologic functions and shall include adverse impacts upstream of, at or downstream of the development proposal site. Mitigation shall be of each function affected by the alteration to achieve functional equivalency or improvement on a per function basis;

B. The buffer of a stream may be increased, as determined by the city, to mitigate risks to stream functions or to the public health, safety, welfare and environment;

C. Mitigation of the adverse impact of alterations to streams or their buffers shall be in the same drainage subbasin and shall include:

1. For permanent alterations, restoration or enhancement of the altered stream or buffer, as determined by the city, using the following formulae:

a. For mitigation on site:

i. Correcting the adverse impact to any class of stream by repairing, rehabilitating or restoring the affected stream or buffer shall be on a 1:1 areal and functional basis;

ii. Enhancement or restoration which is not mitigation of an alteration associated with a Type F, Np or Ns stream shall be on a 1.5:1 area and functional basis;

iii. Enhancement or restoration which is not mitigation of an alteration associated with a Type S stream shall be on a 2:1 area and functional basis;

b. For mitigation off site:

i. Enhancement or restoration which is not mitigation of an alteration associated with a Type F, Np or Ns stream shall be on a 2:1 area and functional basis;

ii. Enhancement or restoration which is not mitigation of an alteration associated with a Type S stream shall be on a 3:1 area and functional basis; and

2. For temporary alterations, restoration of the altered stream or buffer, as determined by the city;

D. The following stream restoration standards shall be applied to all mitigation projects involving stream restoration. Restoration of a stream or buffer shall be carried out under the supervision of a stream scientist and shall be approved to achieve, as closely as possible, the following:

1. Replication of the natural channel dimensions including its depth, width, length and gradient at the historical location;

2. Replacement of the historical horizontal alignment (sinuosity);

3. Restoration of the bottom with identical or similar materials;

4. Restoration of the bank and buffer configuration to its historical condition;

5. Restoration of the historical vegetation in species, sizes and densities in the channel, bank and buffer by replanting with native vegetation; and

6. Restoration of the stream’s historical functions including, but not limited to, its hydrologic and biologic functions;

E. For off-site mitigation:

1. Off-site mitigation shall be approved only if the city determines that:

a. It is not practical to mitigate on site; and

b. Off-site mitigation will achieve biologic, habitat and hydrologic functions equivalent to or better than on-site mitigation;

2. Streams given priority in approved basin plans shall be used for mitigation to the maximum extent practical;

F. Drainage or flood control alterations shall not constitute enhancement unless other affected stream functions are simultaneously approved;

G. Whenever possible, mitigation sites shall be located to achieve contiguous wildlife habitat corridors;

H. The requirements set forth in this section may be modified at the city’s discretion if the applicant demonstrates that greater stream functions, on a per function basis, can be obtained in the affected drainage subbasin as a result of alternative mitigation measures. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1. Formerly 18.24.370).

18.24.310 Wetlands – Categories.

A. Wetlands are classified into Category I, Category II, Category III and Category IV based on the current adopted Washington State Wetland Rating System for Western Washington – 2014 Update, Washington State Department of Ecology publication published October 2014, or as hereafter amended.

B. Wetland rating categories shall not recognize illegal modifications. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.312 Wetlands – Additional critical area reporting requirements.

The critical area study report shall contain the information listed in NMC 18.24.120, Contents of critical area report – General requirements; and an assessment of wetlands. The report will assist in determining the extent, characteristics, functions, and values of any wetlands located on a site where regulated activities are proposed. The report will also be used by the city to determine the appropriate wetland rating and to establish appropriate buffer requirements. The information required by this report should be coordinated with the study and reporting requirements for any other critical areas located on the site including the following site and proposal related information at a minimum:

A. Wetland boundaries shall be staked and flagged in the field by a qualified consultant employing the currently approved federal manual and supplements. Field flagging shall be distinguishable from other survey flagging on the site. The field flagging must be accompanied by a wetland delineation report.

B. The report shall include the following information:

1. Wetland Map. Wetlands shall be located on a site map with an engineering scale of one inch equals 20 feet. The map must show:

a. Delineated wetland boundary and required buffers including buffers for off-site critical areas that extend onto the project site; the development proposal, other critical areas, grading and clearing limits, areas of proposed impacts to wetlands and/or buffers with square footage estimates.

b. A depiction of stormwater management facilities and outlets (to scale) for the development, including estimated areas of intrusion into the buffers of critical areas.

c. Hydrologic mapping showing patterns of water movement into, through, and out of the site area.

d. Location of all test holes and vegetation sample sites, numbered to correspond with flagging in the field and field data sheets.

2. Site designated on a National Wetland Inventory Map (U.S. Fish and Wildlife Service).

3. Wetland Delineation Report. A written wetland delineation report which includes the following information:

a. Delineation methodology, with special emphasis on whether the approach used was routine, comprehensive, or atypical situation as described in the currently approved federal manual and supplements. This shall include an explanation of how the wetland boundary was determined.

b. A wetland assessment. This assessment shall describe specific descriptions of wetlands, including wetland category, classification using the USFWS (Cowardin) Method, vegetative, faunal and hydrologic characterization, soil and substrate conditions, wetland acreage, and required buffers.

c. A wetland characterization using the Wetland Rating System for Western Washington. This characterization identifies the wetland category. The wetland category and “score” shall be part of the description for each wetland. This characterization shall include an analysis of the wetland’s ability to provide the following key functions: provide wildlife, plant, and fisheries habitat; moderate runoff volume and flow rates; reduce sediment, chemical nutrient, and toxic pollutants; provide shading to maintain desirable water temperatures; reduce erosion; and reduce groundwater and surface water pollution.

d. A description of the proposed actions, including an estimation of acreages of impacts to wetlands and buffers based on the field delineation and survey and an analysis of site development alternatives, including a no-development alternative.

e. A summary of proposed wetland and buffer alterations, impacts, and the need for the alterations as proposed. This shall include a mitigation sequencing analysis. Potential impacts may include but are not limited to loss of flood storage potential, loss of wildlife habitat, expected decreases in species diversity or quantity, changes in water quality, increases in human intrusion, and impacts on associated wetland or water resources. If wetland impacts are proposed, a wetland mitigation plan is required according to the standards of NMC 18.24.130, Mitigation and monitoring.

4. Field data sheets from the currently approved federal manual and supplements, numbered to correspond with sample site locations as staked and flagged in the field. This includes Data Form 1: Routine Wetland Determination.

5. Wetland rating forms for each wetland as identified in the Washington State Wetland Rating System for Western Washington. (Ord. 2016-538 § 2 (Exh. 3)).

18.24.315 Wetlands – Buffers.

A. The standard buffer widths listed below 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.

1. The use of the standard buffer widths requires the implementation of the measures in NMC 18.24.316(A), where applicable, to minimize the impacts of the adjacent land uses.

2. If an applicant chooses not to apply the mitigation measures listed in NMC 18.24.316(A), then a 33 percent increase in the width of all buffers is required. For example, a 75-foot buffer with the mitigation measures would be a 100-foot buffer without them.

3. The standard buffer widths 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 that adequate functions of the buffer are provided.

4. Except as otherwise provided in this section, buffers shall be provided from the wetland edge as follows: The buffers shown on the following table apply unless modified in accordance with subsections (B) and (C) of this section:

WETLAND CATEGORY AND CHARACTERISTICS	HIGH TO MODERATE IMPACT LAND USES	LOW IMPACT LAND USES
Category I
Category I wetlands not meeting any of the criteria below	75 feet	50 feet
Wetlands with a conservation value and bogs	190 feet	125 feet
Habitat score from 8 to 9 points	225 feet	150 feet
Habitat score from 6 to 7 points	110 feet	75 feet
Category II
Category II wetlands not meeting any of the criteria below	75 feet	50 feet
Habitat score from 8 to 9 points	225 feet	150 feet
Habitat score from 6 to 7 points	110 feet	75 feet
Category III
Category III wetlands not meeting any of the criteria below	60 feet	40 feet
Habitat score from 8 to 9 points	225 feet	150 feet
Habitat score from 6 to 7 points	110 feet	75 feet
Category IV	40 feet	25 feet

5. High impact land uses must implement the performance standards contained in NMC 18.24.316.

6. For purposes of this subsection (A), unless the director determines a lesser level of impact is appropriate based on information provided by the applicant, the intensity of impact of the adjacent land use is determined as follows:

a. High impact uses include:

i. Sites zoned commercial;

ii. Sites zoned industrial;

iii. Retail sales;

iv. Sites zoned residential (more than one unit/acre);

v. High density recreation (golf courses, ball fields).

b. Moderate impact uses include:

i. Sites zoned residential (one unit/acre or less);

ii. Moderate intensity open space (parks);

iii. Paved trails.

c. Low impact uses include:

i. Low intensity open space (such as passive recreation and natural resource preservation. When the director determines there will be minimal or no adverse effect, the following activities are allowed: educational activities, scientific research, and nonmotorized outdoor recreational activities for small groups, including but not limited to interpretive field trips, birdwatching, public beach access including water-related activities, hiking, and similar activities as authorized by the director. This exemption does not include constructing new roads or vegetation clearing);

ii. Unpaved trails.

B. The department may approve a modification of the minimum buffer width required by this section by averaging the buffer width if:

1. The department determines that:

a. The ecological structure and function of the buffer after averaging is greater than the structure and function before averaging;

b. Averaging includes connecting the corridors of a wetland complex; and

2. The resulting buffer meets the following standards:

a. The total area of the buffer after averaging is equivalent to or greater than the area of the buffer before averaging;

b. The additional buffer is contiguous with the standard buffer;

c. No feasible alternative to the site design could be accomplished without buffer averaging; and

d. The buffer width may be reduced by no more than 25 percent of the standard width at any point, down to a minimum of 35 feet.

C. Wetland buffer widths shall also be subject to modifications under the following special circumstances:

1. For wetlands containing documented habitat for endangered, threatened, priority species or species of local importance, the following shall apply:

a. The department shall establish the appropriate buffer, based on a habitat assessment, to ensure that the buffer provides adequate protection for the critical species; and

2. For a wetland buffer that includes a steep slope hazard area or landslide hazard area, the buffer width is the greater of either the buffer width required by the wetland’s category in this section or 25 feet beyond the top of the hazard area. Wetland buffers that include steep slope hazard areas are not subject to buffer averaging provisions; and

3. For a wetland complex, the buffer width is determined as follows:

a. The buffer width for each individual wetland in the complex is the same width as the buffer width required for the category of wetland;

b. If the buffer of a wetland within the complex does not touch or overlap with at least one other wetland buffer in the complex, a corridor is required from the buffer of that wetland to one other wetland buffer in the complex considering the following factors:

i. The corridor is designed to support maintaining viable wildlife species that are commonly recognized to exclusively or partially use wetlands and wetland buffers during a critical life cycle state, such as breeding, rearing, or feeding;

ii. The corridor minimizes fragmentation of the wetlands;

iii. High category wetlands are connected through corridors before lower category wetlands;

iv. The corridor width is at least 25 percent of the length of the corridor, but no less than 25 feet in width; and

v. Shorter corridors are preferred over longer corridors;

c. Wetlands in a complex that are connected by an aquatic area that flows between the wetlands are not required to be connected through a corridor;

d. The department may exclude a wetland from the wetland complex if the applicant demonstrates that the wetland is unlikely to provide habitat for wildlife species that are commonly recognized to exclusively or partially use wetlands and wetland buffers during a critical life cycle stage, such as breeding, rearing, or feeding; and

4. Where a legally established roadway or driveway transects a wetland buffer, the department may approve a modification of the minimum required buffer width to the edge of the roadway or driveway if the part of the buffer on the other side of the roadway or driveway sought to be reduced:

a. Does not provide additional protection of the proposed development or the wetland; and

b. Provides insignificant biological, geological or hydrological buffer functions relating to the other portion of the buffer adjacent to the wetland; and

5. Where a legally established roadway or driveway transects a wetland, the wetland may be divided into different units based on guidance provided in the Washington State Wetland Rating System for Western Washington – 2014 Update, October 2014 (Washington State Department of Ecology) or as amended.

D. Where a structure legally established on a site prior to December 1, 2005, encroaches into the critical area buffer established in subsection (A) of this section, the footprint of the existing structure shall be exempt from the required critical area buffer. (Ord. 2022-645 § 11; Ord. 2020-621 § 5; Ord. 2016-538 § 2 (Exh. 3); Ord. 2006-335 § 1; Ord. 2005-325 § 5).

18.24.316 Wetlands – Development standards.

A. High impact land uses affecting wetlands must meet the performance standards outlined below:

Disturbance	Measures to Minimize Impacts	Activities That May Cause the Disturbance
Lights	Direct lights away from wetland	Parking lots, warehouses, manufacturing, high density residential
Noise	Place activity than generates noise away from the wetland	Manufacturing, high density residential
Toxic runoff	Route all new untreated runoff away from wetland; or Covenants limiting use of pesticides and herbicides within 150 feet of wetland; or Implement integrated pest management program	Parking lots, roads, manufacturing, residential areas, application of agricultural pesticides, landscaping
Change in water regime	Infiltrate or treat, detain and disperse into buffer new runoff from impervious surfaces	Any impermeable surface, lawns, tilling
Pets and human disturbance	Privacy fencing or landscaping to delineate buffer edge and to discourage disturbance of wildlife by humans and pets	Residential areas
Degraded buffer condition	Nonnative plants to be removed and replaced with native vegetation per an approved landscaping plan to be bonded and monitored for a five-year period after completion to assure at least 80 percent survival of plantings	All activities potentially requiring buffers

B. In addition to meeting the performance standards above, high impact land uses affecting wetlands with a habitat score of five points or more that are within 300 feet of a fish and wildlife conservation area must also meet the following performance standards:

1. Provide a relatively undisturbed vegetated corridor at least 100 feet wide between the wetland and all fish and wildlife habitat conservation areas located within 300 feet of the wetland; and

2. The corridor shall be protected for the entire distance between the wetland and the fish and wildlife conservation area through dedication to the city or a conservation easement, as determined by the city. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.320 Wetlands – Permitted alterations.

If the department determines that there is no practical alternative location with less adverse impact on the wetland or its buffer, then alterations to wetlands and buffers may be allowed pursuant to applicable permits or approvals and subject to mitigation requirements set forth in this chapter, as follows:

A. Public and private utility corridors in wetland buffers if:

1. The utility corridor is not located in a buffer where the buffer or associated wetland is used as a fish spawning area or by species listed as endangered or threatened by the state or federal government or contains critical or outstanding actual habitat for those species or heron rookeries or raptor nesting trees;

2. The construction area and resulting utility corridor are the minimum widths practical;

3. Except as provided in subsection (G) of this section, the utility corridor is located within the outer 25 percent of the buffer or within a roadway, the improved area of an existing utility corridor or the improved area of an approved trail;

4. The wetland and its buffer are protected during utility corridor construction and maintenance;

5. The utility corridor is aligned to avoid cutting significant trees, to the maximum extent practical;

6. Vegetation removal is limited to the minimum necessary to construct the corridor;

7. Vegetation removal for the purpose of corridor maintenance is the minimum necessary to maintain the utility’s function;

8. Any corridor access for maintenance is at specific points into the buffer rather than by a parallel road, to the maximum extent practical;

9. If the department determines that a parallel maintenance road is necessary, the following conditions shall be complied with:

a. The width of the roadway shall be as small as possible and not greater than 15 feet; and

b. The location of the roadway shall be contiguous to the utility corridor on the side farthest from the wetland;

10. Additional requirements for sewer utility and public water distribution corridors are complied with, as follows:

b. An additional, contiguous and undisturbed buffer, equal in width to that part of the proposed sewer utility or public water distribution corridor located in the original wetland buffer including any allowed maintenance roads, is provided to protect the wetland;

B. Joint use of an approved utility corridor by other utilities;

C. Surface water conveyance or discharge in the buffer if the department finds that:

1. The discharge does not:

a. Increase the rate of flow above the predevelopment rate;

b. Change the plant composition in a bog, fen or wetland with a forested wetland vegetation class;

c. Decrease the water quality of the wetland; and

d. Decrease the quality of fish spawning and rearing areas; and

2. Stormwater Management Facilities. Stormwater management facilities are limited to stormwater dispersion outfalls and bioswales. They may be allowed within the outer 25 percent of the buffer of Category III or IV wetlands only; provided, that:

a. No other location is feasible; and

b. The location of such facilities will not degrade the functions or values of the wetland; and

c. Stormwater management facilities are not allowed in buffers of Category I or II wetlands;

D. Except as provided in subsection (G) of this section, public and private trails in wetland buffers in compliance with requirements set forth in administrative rules and with the following:

2. Buffers shall be expanded, where possible, equal to the width of the trail corridor including disturbed areas;

E. A category IV wetland less than 2,500 square feet may be altered by relocating its functions into a new wetland on the site in accordance with an approved mitigation plan if the wetland:

1. Is not part of a wetland complex.

2. Is not associated with riparian areas or their buffers.

3. Is not associated with shorelines of the state or their associated buffers.

4. Does not score five or more habitat points.

5. Does not contain a priority habitat or a priority area for a priority species identified by the Washington Department of Fish and Wildlife; and does not contain federally listed species or their critical habitat, or a species of local importance identified in NMC 18.24.302.

6. If the alteration to any wetland under this subsection is a flow control facility, the water shall be pretreated to remove at least 50 percent of the total suspended solids;

F. The following vegetation removal activities:

1. Where not exempt, the removal of noxious weeds from wetlands and their buffers;

2. The removal of the following vegetation from wetlands and their buffers with hand labor and light equipment:

a. Himalayan blackberry (Rubus discolor, R. procerus);

b. Evergreen blackberry (Rubus laciniatus);

c. Other invasive species as determined by the department;

3. The removal of vegetation from wetland buffers, only as necessary, for surveying purposes; and

4. The removal of hazard trees from wetlands and buffers; provided, that a certified arborist determines that the trees are classified as hazards as determined by the department;

G. Wetland and buffer road and underground utility crossings if:

1. The department determines that there is no feasible alternative location outside the critical area or buffer with less adverse impact on the wetland or its buffer;

2. The crossing does not change the overall wetland hydrology;

3. The crossing does not diminish the flood storage capacity of the wetland;

4. The crossing is constructed during the summer low flow period;

5. The crossing is located where it has the least adverse impact on the wetland and buffer which generally will be the shortest distance across the wetland or its buffer;

6. The crossing is not located over fish rearing or spawning habitat unless the department determines that there is no other possible crossing site;

7. Vegetation removal is limited to the minimum necessary to construct the crossing;

8. Vegetation removal for the purpose of the crossing’s maintenance is the minimum necessary to maintain the utility’s function;

9. Additional requirements for underground utility crossings are complied with, as follows:

a. Trench dams or other equivalent techniques approved by the department shall be placed along the utility corridor to avoid draining the wetland;

b. The crossing is made in a manner which and located where it will not alter fish rearing habitat; and

c. Crossings shall also comply with all applicable requirements for utility corridors set forth in subsection (A) of this section;

10. Crossings are minimized and serve multiple purposes and properties whenever possible; and

11. All unavoidable impacts are fully mitigated;

H. Exploratory drilling and testing, involving only necessary and limited clearing and grading, for the purpose of preparing critical area reports;

I. The application of herbicides, pesticides, organic or mineral-derived fertilizers, or other hazardous substances, if necessary, as approved by the department and in accordance with regulations of the State Department of Agriculture, the U.S. Environmental Protection Agency, and the Department of Ecology. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.325 Wetlands – Specific mitigation requirements.

In addition to requirements in NMC 18.24.125 and 18.24.130, the following applies to mitigation to compensate for the adverse impacts associated with an alteration to a wetland or wetland buffer:

A. Mitigation measures must achieve equivalent or greater wetland functions, including, but not limited to:

1. Habitat complexity, connectivity and other biological functions; and

2. Seasonal hydrological dynamics, as provided in the King County Surface Water Design Manual;

B. The following ratios of area of mitigation to area of alteration apply to mitigation measures:

1. For alterations to a wetland buffer, a ratio of one to one; and

2. For alterations to a wetland, proposed mitigation shall be in compliance with the acreage replacement ratios listed below:

	Acreage Replacement Ratios for Wetland Mitigation
Category and Type of Wetland	Wetland Reestablishment or Creation	Wetland Rehabilitation	1:1 Wetland Reestablishment or Wetland Creation (R/C) and Wetland Enhancement (E)	Wetland Enhancement Only
Category I based on score for functions	4:1	8:1	1:1 R/C and 6:1 E	16:1
Category I forested	6:1	12:1	1:1 R/C and 10:1 E	24:1
Category II	3:1	6:1	1:1 R/C and 4:1 E	12:1
Category III	2:1	4:1	1:1 R/C and 2:1 E	8:1
Category IV	1.5:1	3:1	1:1 R/C and 2:1 E	6:1

C. Credit/Debit Method. To more fully protect functions and values, and as an alternative to the mitigation ratios found in the joint guidance Wetland Mitigation in Washington State Parts I and II (Ecology Publication No. 06-06-011a-b, Olympia, WA, March 2006), the administrator may allow mitigation based on the “credit/debit” method developed by the Department of Ecology in Calculating Credits and Debits for Compensatory Mitigation in Wetlands of Western Washington: Final Report (Ecology Publication No. 10-06-011, Olympia, WA, March 2012, or as revised). (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.330 Wetlands – Agreement to modify mitigation ratios.

A. The department may enter into an agreement with an applicant to establish mitigation ratios to compensate for the adverse impacts to wetlands of the applicant’s development proposal that differ from the ratios required in NMC 18.24.325. The agreement shall require that the applicant:

1. Demonstrate with scientifically valid data that the program implemented by the applicant will achieve long-term success in reducing the risk of failure and temporal loss of function of the applicant’s wetland mitigation projects; and

2. Implement a scientifically rigorous mitigation, monitoring and adaptive management program that includes the following elements:

a. A mitigation planning process that requires mitigation plans to be prepared and signed by a qualified wetland specialist. The mitigation planning process shall use the guidelines contained in Washington State Department of Ecology – U.S. Army Corps of Engineers Publication 04-06-013b, “Guidance on Wetland Mitigation in Washington State” or an alternative approach acceptable to the department;

b. Construction oversight by a qualified wetland specialist;

c. Post-construction monitoring and reporting by experienced and qualified personnel using scientifically rigorous and accepted methodologies to assess whether the mitigation has been installed and whether it meets the approved goals, objectives and performance standards identified in the mitigation plan;

d. Ongoing mitigation site maintenance to facilitate the achievement of the approved goals, objectives and performance standards identified in the mitigation plan. Maintenance includes, but is not limited to, the removal and control of nonnative vegetation, replacement of dead or dying vegetation, replacement of signage, repair of fencing, and trash and debris removal;

e. Financing or funding guarantees for the duration of the mitigation and monitoring program. At a minimum, financial guarantees must be in place until mitigation activities have met the established performance standards and have been approved by the department; and

f. An adaptive management program that requires the evaluation and adjustment of remedial actions contained within the contingency plan developed as part of the mitigation planning process.

B. The mitigation ratios established by the agreement authorized by this section shall be based on data prepared by the applicant regarding the effectiveness of past and ongoing mitigation projects implemented and monitored by the applicant. In establishing the mitigation ratios, the department shall consider the following:

1. The applicant’s demonstrated success in meeting mitigation performance standards for the different types of mitigation, such as reestablishment, creation, rehabilitation, and enhancement; and

2. The hydrogeomorphic classification, such as slope, riverine, depressional and tidal fringe, of the wetland.

C. The applicant may request coordinated review of the agreement with the Washington State Department of Ecology and the United States Army Corps of Engineers. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5).

18.24.377 Critical areas violations – Corrective work required.

A. Any person who alters a critical area or buffer in violation of law shall undertake corrective work in compliance with the requirements of this chapter and Chapter 17.07 NMC. Corrective work shall include restoration of the critical area and buffer. Corrective work shall be subject to all permits or approvals required for the type of work undertaken. In addition, the violator shall be subject to all fees associated with investigation of the violation and the need for corrective work.

B. When a wetland or buffer is altered in violation of law, restoration of the wetland and buffer shall comply with the restoration standards set forth in this chapter.

C. When a stream or buffer is altered in violation of law, restoration of the stream and buffer shall comply with the restoration standards set forth in this chapter.

D. All corrective work shall be completed within the time specified in the corrective work plan, but in no case later than one year from the date the corrective work plan is approved by the city. The violator shall notify the city when restoration measures are installed and monitoring is commenced.

E. Any failure to satisfy corrective work requirements established by law or condition including, but not limited to, the failure to provide a monitoring report within 30 days after it is due or comply with other provisions of an approved corrective work plan shall constitute a default, and the city may demand payment of any financial guarantees or require other action authorized by the Newcastle Municipal Code or other applicable law.

F. Reasonable access to the corrective work site shall be provided to the city for the purpose of inspections during any monitoring period. (Ord. 2021-634 § 6, 2021; Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.378 Critical areas violations – Corrective work monitoring requirement.

Corrective work shall be monitored in accordance with the provisions of the approved corrective work plan. Monitoring may be required for a period of up to five years. Monitoring pursuant to the corrective work plan shall comply with the monitoring requirements set forth in this chapter. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.379 Critical areas violations – Corrective work plan requirement.

A. The violator shall submit a proposed corrective work plan to the city for approval. The city may modify the plan and shall approve it only if the city determines that the plan complies with the requirements for mitigation plans set forth in this chapter.

B. All corrective work shall be accomplished according to the approved corrective work plan, and no corrective work shall be undertaken until after approval of the plan by the city. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.380 Critical areas mitigation fee – Creation of fund.

There is hereby created a critical areas mitigation fund. This fund shall be administered by the city. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.390 Critical areas mitigation fee –Source of funds.

All moneys received from penalties resulting from the violation of rules and laws regulating development and activities within critical areas shall be deposited into the fund. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.400 Critical areas mitigation fee – Use of funds.

Moneys from the fund shall only be used for paying the cost of enforcing and implementing critical area laws and rules. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).

18.24.410 Critical areas mitigation fee –Investment of funds.

Moneys in the fund not needed for immediate expenditure shall be deposited in a separate investment fund pursuant to RCW 36.29.020. The city manager shall be designated as the investment fund manager. (Ord. 2016-538 § 2 (Exh. 3); Ord. 2005-325 § 5; Ord. 2005-311 § 1; Ord. 2000-224 § 1).