16.10.100 Alteration or development of critical areas – Standards and criteria – Prohibited uses

16.10.100 Alteration or development of critical areas – Standards and criteria – Prohibited uses.

Alteration of specific critical areas and/or their buffers may be allowed by the director subject to the criteria of this section. Alteration shall implement the mitigation standards as identified in ACC 16.10.110, and the performance standards of ACC 16.10.120 and the monitoring requirements of ACC 16.10.130.

1. Category I Wetlands. Alterations of Category I wetlands shall be avoided subject to the reasonable use provisions of this chapter.

a. Alteration and mitigation shall comply with the mitigation performance standards and requirements of these regulations;

b. Where enhancement, restoration or creation is proposed, replacement ratios shall comply with the requirements of these regulations; and

c. No net loss of wetland functions and values may occur.

a. Alteration and mitigation shall comply with the mitigation performance standards and requirements of these regulations;

b. Where enhancement, restoration or creation is proposed, replacement ratios shall comply with the requirements of these regulations; and

c. No net loss of wetland functions and values may occur.

d. The following wetlands may be exempt from the requirement to avoid impacts and they may be filled if the impacts are fully mitigated based on the remaining actions. If available, impacts should be mitigated through the purchase of credits from an in-lieu fee program or mitigation bank, consistent with the terms and conditions of the program or bank. Mitigation requirements may be determined using the credit/debit tool described in Calculating Credits and Debits for Compensatory Mitigation in Wetlands of Western Washington: Final Report (Ecology Publication No. 10-06-011, or as revised and approved by Ecology). In order to verify the following conditions, a critical area report for wetlands meeting the requirements in ACC 16.10.060 must be submitted.

i. All non-federally-regulated Category IV wetlands less than 4,000 square feet that:

(A) Are not associated with riparian areas or their buffers.

(B) Are not associated with shorelines of the state or their associated buffers.

(D) Do not score six or more points for habitat function based on the 2014 update to the Washington State Wetland Rating System for Western Washington: 2014 Update (Ecology Publication No. 14-06-029, or as revised and approved by Ecology).

(E) Do not contain a priority habitat or a priority area for a priority species identified by the Washington Department of Fish and Wildlife, do not contain federally listed species or their critical habitat, or species of local importance identified in ACC 16.10.080(E).

ii. Wetlands less than 1,000 square feet that meet the above criteria and do not contain federally listed species or their critical habitat are exempt from the buffer provisions contained in this chapter.

1. Relocation of a Type F, Np and Ns stream exclusively to facilitate general site design shall not be allowed. Relocation of a stream may take place only when it is part of an approved mitigation or enhancement/restoration plan, and will result in equal or better habitat and water quality, and will not diminish the flow capacity of the stream.

2. Bridges shall be used to cross Type S streams; boring/micro-tunneling may be considered for utility crossings if it would result in the same or lower impacts as bridging.

3. Culverts are allowable only under the following circumstances:

a. Only in Type F, Type Np, and Type Ns streams;

b. When fish passage will not be impaired;

c. When the following design criteria are met:

i. All new culverts shall be designed following guidance provided in the Washington Department of Fish and Wildlife’s document: Water Crossing Design Guidelines, 2013 (or most recent version thereof). The applicant shall obtain a HPA from the Department of Fish and Wildlife;

ii. Culverts will include gradient controls and creation of pools within the culvert for Type F streams;

iii. Gravel substrate will be placed in the bottom of the culvert to a minimum depth of one foot for Type F and Type Np streams;

d. The applicant or successors shall, at all times, keep any culvert free of debris and sediment to allow free passage of water and, if applicable, fish. This responsibility shall be part of the required long-term preservation measure and may be subject to securing all the necessary approvals for any ongoing maintenance.

4. The city may require that an existing culvert be removed from a stream as a condition of approval, unless the culvert is not detrimental to fish habitat or water quality, or removal would be a long-term detriment to fish or wildlife habitat or water quality.

1. Critical Habitat. Alterations of critical habitat shall be avoided, subject to the reasonable use provisions of this chapter.

2. Secondary Habitat. Alterations of secondary habitat may be permitted; provided, that the applicant mitigates adverse impacts consistent with the performance standards of ACC 16.10.120, and other requirements of this chapter.

3. Tertiary Habitat. Alterations of tertiary habitat are permitted consistent with applicable provisions of these regulations and provided that no other regulated critical area is present.

D. Aquifer Recharge Areas. The following land uses and activities applied for on or after the effective date of the ordinance codified in this chapter, as amended, shall be prohibited in Type I aquifer recharge areas:

1. Class V injection wells that inject industrial, municipal, or commercial waste fluids (as defined in WAC 173-218-030);

2. Surface impoundments for treating, storing and disposing of dangerous waste (as defined in WAC 173-303-040 and 173-304-100);

3. Waste piles for treating or storing solid waste (as defined in WAC 173-303-040, 173-303-660 and 173-304-420);

4. Hazardous waste treatment, storage, and disposal (as defined in WAC 173-303-040);

5. All types of solid waste landfills (as defined in WAC 173-304-100);

6. On-site sewage systems (as defined in Chapter 246-272A WAC) except as related to R-C, residential conservancy zoned properties and properties located within sole source aquifer (community well sites not classified as groundwater protection areas) five- and 10-year time of travel areas. On-site sewage systems may be allowed in instances that there are no other means of sewage disposal and the applicant can demonstrate to the King County health department that the system can meet treatment standard N, as provided in WAC 246-272A-0110. Should an on-site sewage system be unable to meet these requirements, the applicant may apply for a critical areas variance in accordance with this chapter.

7. Recycling facilities that accept, store, or use hazardous substances as defined in WAC 173-218-030.

8. Underground storage of hazardous substances as defined in WAC 173-218-030, excluding the underground storage of petroleum and other substances as regulated by Chapter 173-360A WAC;

9. Use, storage, treatment, or production of perchlorethylene (PCE) or tetrachloroethylene (PERC), other than in closed-loop systems that do not involve any discharge of chemicals;

10. Petroleum refining, reprocessing, and storage, excluding the underground storage of petroleum products and other substances as regulated by Chapter 173-360A WAC;

11. Petroleum-product pipelines not associated with underground storage of petroleum and other regulated substances as regulated by Chapter 173-360 WAC; and

12. Storage or distribution of gasoline treated with the additive methyl tertiary butyl ether (MTBE).

1. General Standards. The city may approve, condition or deny proposals for the alteration of geologically hazardous areas, as appropriate, based on the degree to which the significant risks posed by critical hazard areas to public and private property and to public health and safety can be mitigated. The objective of mitigation measures shall be to render a site containing a critical geologic hazard as safe as one not containing such hazard or one characterized by a low hazard. In appropriate cases, conditions may include limitations of proposed uses, modification of density, alteration of site layout and other appropriate changes to the proposal. Where potential impacts cannot be effectively mitigated or where the risk to public health, safety and welfare, public or private property, or important natural resources is significant notwithstanding mitigation, the proposal shall be denied.

a. Class IV Landslide Hazard Areas. Alteration shall be prohibited subject to the reasonable use provisions of this chapter.

i. For one-story and two-story residential structures, the applicant shall conduct an evaluation of site response and liquefaction potential based on the performance of similar structures under similar foundation conditions; or

ii. For all other proposals, the applicant shall conduct an evaluation of site response and liquefaction potential including sufficient subsurface exploration to provide a site coefficient (S) for use in the static lateral force procedure described in the International Building Code.

c. When development is permitted in geologically hazardous areas by these regulations, an applicant and/or its qualified consultant shall provide assurances which, at the city’s discretion, may include one or more of the following:

i. A letter from the geotechnical engineer and/or geologist who prepared the geotechnical report required by these regulations, stating that the risk of damage from the proposal, both on site and off site, is minimal subject to the conditions set forth in the report, that the proposal will not increase the risk of occurrence of the potential geologic hazard, and that measures to eliminate or reduce risks have been incorporated into its recommendations;

ii. A letter from the applicant, or the owner of the property if not the applicant, stating its understanding and acceptance of any risk of injury or damage associated with development of the site and agreeing to notify any future purchasers of the site, portions of the site, or structures located on the site of the geologic hazard;

iii. A legally enforceable hold harmless agreement, which shall be recorded as a covenant and noted on the face of the deed or plat, and executed in a form satisfactory to the city, acknowledging that the site is located in a geologically hazardous area; the risks associated with development of such site; and a waiver and release of any and all claims of the owner(s), their directors, employees, or successors, or assigns against the city of Auburn for any loss, damage, or injury, whether direct or indirect, arising out of issuance of development permits for the proposal; and

iv. Posting of a bond, guarantee or other assurance device approved by the city to cover the cost of monitoring, maintenance and any necessary corrective actions.

F. Flood Hazard Areas. Development standards are defined by Chapter 15.68 ACC. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 5894 § 1, 2005.)