A. 
Geologically hazardous areas include erosion hazards, landslide hazards, mine hazards, volcanic hazards and seismic hazards, and shall be designated consistent with the definitions provided in WAC 365-190-080(4).
B. 
Geologically hazardous areas shall be classified as "known or suspected risk," or "unknown risk."
(Ord. 1853 § 2 (Exh. B), 2018)
A site visit shall be conducted by the city to determine whether: (A) "Areas of known or suspected risk" identified below are or may be present within 300 feet of the project or activity; (B) the proposed project or activity is or may be within a distance from the base of an adjacent landslide hazard area equal to the vertical relief of said hazard area; (C) the proposed activity may result in or contribute to an increase in hazard; and (D) whether the project or hazard areas pose a risk to life, property, or other critical areas on or off the project area sufficient to require a site assessment. The city may require that the site visit be conducted by a licensed geotechnical professional. Areas of known or suspected risk:
A. 
Erosion Hazard Indicators.
1. 
Those project areas located within 300 feet of map unit delineations No. 51 Dystic Xerorthents, No. 99 Mundt and No. 117 Saxon or mapped as moderate to severe, severe or very severe erosion hazard or as having severe rill and inter-rill erosion hazard as identified in the U.S. Department of Agriculture Natural Resources Conservation Service Soil Survey of Skagit County Area, WA (1989) or most currently adopted.
2. 
Those project areas that fall within any soil sloping greater than or equal to 30 percent.
3. 
The project area falls within areas designated in the Department of Ecology, Coastal Zone Atlas, Washington, Volume Two Skagit County (1978 or most currently adopted) as U (Unstable), UB (Unstable Bluff), URS (Unstable Recent Slide), or UOS (Unstable Old Slide).
4. 
Those project areas that may be considered to have an erosion hazard as a result of rapid stream incision or stream bank erosion.
B. 
Landslide Hazard Indicators.
1. 
The project area falls within or 300 feet from areas designated in the Department of Ecology, Coastal Zone Atlas, Washington, Volume Two, Skagit County (1978 or most currently adopted) as U (Unstable), UB (Unstable Bluff), URS (Unstable Recent Slide), or UOS (Unstable Old Slide);
2. 
The project area falls within or 300 feet from slopes having the following characteristics: gradients of 15 percent or greater intersecting geologic contacts with permeable sediments overlying low permeability sediment or bedrock and springs or ground water seepage are present;
3. 
The project area falls within or 300 feet from any area having a 40 percent slope or steeper and with a vertical relief of 10 feet or more;
4. 
The project area falls within or 300 feet from any areas of historic failure such as areas designated as quaternary earth slumps, earthflows, mudflows, lahars, debris flows, rock slides, landslides or other slope failures on maps or technical reports published by the U.S. Geological Survey such as topographic or geologic maps, or the Geology and Earth Resources Division of the Washington Department of Natural Resources, or other documents authorized by government agencies;
5. 
The project area falls within or 300 feet from any areas potentially unstable as a result of rapid stream incision, stream bank erosion, and undercutting by wave action shall be addressed as a flood hazard consistent with this chapter;
6. 
Areas that have shown movement during the Holocene epoch or which are underlain or covered by wastage debris of that epoch;
7. 
The project area falls within or 300 feet from any slopes that are parallel or sub-parallel to planes of weakness (such as bedding planes, joint systems, and fault planes) in subsurface materials;
8. 
The project area falls within or 300 feet from any slopes with a gradient greater than 80 percent and subject to rock fall during seismic shaking;
9. 
The project area falls within or 300 feet from any areas that show evidence of or are at risk from snow avalanches.
C. 
Seismic Hazards. Seismic hazard areas shall include areas that are subject to severe risk of damage as a result of earthquake induced ground shaking, slope failure, settlement, soil liquefaction or surface faulting.
1. 
The project includes structures (as defined in the International Building Code) proposed to be located in any of the areas described in subsection (A) or (B) of this section or located in areas to have a potential for soil liquefaction and soil strength loss during ground shaking as identified on the U.S. Geologic Survey Relative Slope Stability Map of the Port Townsend Quadrangle, Puget Sound Region, Washington (1985 or most currently adopted), or as identified in the field. A geologic hazard site assessment is not required for soil liquefaction and soil strength loss resulting from seismic activity unless other criteria provided in this section apply. The building official shall require evaluation using the provisions set forth in the adopted building code.
2. 
The structures or critical facilities are proposed to be located on a Holocene fault line. (No critical facilities shall be located on a Holocene fault line as indicated on investigative maps or described in studies by the United States Geologic Survey, Geology and Earth Resources Division of the Washington Department of Natural Resources or other documents authorized by government agencies, or as identified in the field.) All developments on a Holocene fault line shall require a disclosure statement indicating the property is located on an active fault and may be geologically hazardous.
D. 
Volcanic Hazards. The project area is located in a volcanic hazard zone for Glacier Peak, Washington (Open-File Report 95-499); or in a volcanic hazard area of Mount Baker, Washington (Open-File Report 95-498). A site assessment is not required for volcanic hazard areas unless other criteria provided in this section apply.
E. 
Other Geologic Hazard Indicators.
1. 
The project area falls within or 300 feet from an alluvial fan as designated on the Skagit County Alluvial Fan Study Orthophoto Maps;
2. 
The project area falls within or 300 feet from a mine hazard area as designated on the Department of Natural Resources Map: Coal Measures of Skagit County (1924) or within 300 feet of any other current or historic mine operations determined to be geologic hazards as described in this title, geologically hazardous areas;
3. 
Areas of Unknown Geologic Hazards. As part of any development application where no current information is available to confirm that the items identified in this section are present on the project area, the critical areas review required by this chapter shall provide a description of the known and visible site features and be used by the city in evaluating whether a geologically hazardous area site assessment is required pursuant to this section.
(Ord. 1853 § 2 (Exh. B), 2018; Ord. 1933 § 1 (Exh. A), 2023)
A. 
Site Visit Determination. A determination shall be made as follows:
1. 
No Site Assessment. Where the city determines that the project or activity area has no potential for impacting adjacent ownership and property, other types of critical areas, public property (such as roads and other facilities) or living quarters of any kind, including any existing or proposed off site, no additional site assessments shall be required prior to approval under the provisions of this chapter.
2. 
Site Assessment Required. If the city determines during the site visit that the proposed development activity falls within 300 feet of an "Area of Known or Suspected Risk" and the geologic condition may pose a risk to life and property on or off the project area, then a geologically hazardous area site assessment of the project area by a qualified professional as described in subsection (B) of this section shall be required as part of the complete development permit application.
3. 
Burlington Hill Special Management Area. A site assessment report shall be prepared for all proposed development activities within the Burlington Hill special management area.
B. 
Geologically Hazardous Area Site Assessment. Site assessment reports shall be prepared by a geotechnical professional.
The geologically hazardous area site assessment report shall classify the type of hazard in accordance with this title. The site assessment report shall include the following as appropriate:
1. 
A site plan must be prepared in accordance with the development permit requirements. The site plan shall depict the height of slope, slope gradient and cross section of the site. The site plan shall indicate the location of all existing structures, proposed structures and any significant known geologic features on the subject site. The site plan shall also include the location of springs, seeps, or other surface expressions of ground water. The site plan shall also depict any evidence of surface water or storm water runoff;
2. 
A detailed description of the project, its relationship to potential geologic hazard(s), and its potential impact upon the hazard area(s), the subject property and adjacent properties. The description shall make a determination if a geologically hazardous area(s) is present on the subject site.
The narrative shall include a full discussion of the geologic factors and conditions on the subject site resulting in the qualified professional's conclusions;
3. 
An assessment of the geologic characteristics and engineering properties of the soils, sediments, and/or rock of the subject property and potentially affected adjacent properties. Soils analysis shall be accomplished in accordance with the Unified Soil Classification System;
4. 
A description of load intensity including surface water and ground water conditions, public and private sewage disposal systems, fills and excavations and all structural development;
5. 
An assessment describing the extent and type of vegetative cover to include tree attitude;
6. 
For potential landslide hazards: estimate slope stability and the effect construction and placement of structures will have on the slope over the estimated life of the structure. Quantitative analysis of slope stability or slope stability modeling may be required by the city;
7. 
Additional site assessment standards may be required if necessary to demonstrate compliance with this chapter.
C. 
Site Assessment Conclusions.
1. 
Where the geotechnical professional determines that a geologically hazardous condition is not present on the subject site and/or will not occur as a result of the proposed project, will have no potential for impacting adjacent ownership and property, other types of critical areas, public property (such as roads and other facilities) or living quarters of any kind, including any existing or proposed off site, no additional site assessments shall be required prior to approval under the provisions of this chapter. The qualified professional shall be required to certify that a geologic hazard is not present on the subject parcel.
2. 
Properties containing geologically hazardous conditions shall require a geologically hazardous area mitigation plan. Essential public facilities shall not be sited within designated geologically hazardous areas (Exception: volcanic hazard areas). No residential structures shall be located in geologically hazardous areas or their buffers that cannot be fully mitigated.
(Ord. 1853 § 2 (Exh. B), 2018; Ord. 1933 § 1 (Exh. A), 2023)
The mitigation plan shall be prepared by a geotechnical professional and include a discussion on how the project has been designed to avoid and minimize the impacts. The plan shall also make a recommendation for the minimum building setback from any bluff or slope edge and/or other geologic hazard shall be based upon the geotechnical analysis required under this title. Mitigation plans shall include the location and methods of drainage, locations and methods of erosion control, a vegetation management and/or restoration plan and/or other means for maintaining long-term stability of geologic hazards. The plan shall also address the potential impact of mitigation on the hazard area, the subject property and affected adjacent properties. The mitigation plan must be approved by the city and be implemented as a condition of project approval.
Within designated geologic hazards, mitigation plans shall address the appropriate items listed below as required by the site assessment. One or more of the following mitigation standards shall be included as components of a mitigation plan pursuant to the requirements of this title, site assessment report. Other mitigation standards, other than those listed below, may be required depending on the geologic hazard and the site conditions.
A. 
Mitigation Standards.
1. 
A temporary erosion and sedimentation control plan prepared in accordance with the requirements of this title, surface water management, as amended.
2. 
A drainage plan for the collection, transport, treatment, discharge and/or recycle of water in accordance with the requirements of this title, surface water management, as amended.
3. 
All proposals involving excavations and placement of fills shall be subject to structural review under the appropriate provisions as found in the International Building Code.
4. 
Critical facilities shall not be sited within designated geologically hazardous areas. (Exception: volcanic hazard areas.)
5. 
Surface drainage shall not be directed across the face of a landslide hazard (including ravines). If drainage must be discharged from the hazard area into adjacent waters, it shall be collected above the hazard and directed to the water by tight line drain and provided with an energy dissipating device at the point of discharge.
6. 
All infiltration systems such as storm water detention and retention facilities, and curtain drains utilizing buried pipe or French drain, are prohibited in geologically hazardous areas and their buffers unless a site assessment report indicates such facilities or systems will not affect slope stability and the systems are designed by a licensed civil engineer. The engineer shall also certify that the system and/or facilities are installed as designed.
7. 
Vegetation Removal and Replanting. Removal of vegetation in landslide hazard, erosion hazard and coastal bluff hazard areas shall be minimized. Any replanting that occurs shall consist of trees, shrubs, and ground cover that is compatible with the existing surrounding vegetation, meets the objectives of erosion prevention and site stabilization, and does not require permanent irrigation for long-term survival.
8. 
A minimum buffer with a width of 30 feet shall be established from the top, toe and all edges of all landslide hazardous areas. Existing native vegetation shall be maintained in accordance with mitigation recommendations within the buffer area. Any modifications to the buffer requirement shall be based on the report and recommendations of the professional geologist under supervision of a licensed professional engineer. The buffer may be reduced to a minimum of 10 feet when an applicant demonstrates to the director that the reduction will adequately protect the proposed development, adjacent developments and uses and the subject critical area. The buffer may be increased by the community development director for development adjacent to a ravine which is designated as unstable on the Coastal Zone Atlas, Washington, Volume Two Skagit County (1978 or most current edition) or where a larger buffer is necessary to prevent risk of damage to proposed and existing development (as in the case where the area potentially impacted by a landslide exceeds 30 feet). Normal nondestructive pruning and trimming of vegetation for maintenance purposes, or thinning of limbs of individual trees to provide a view corridor, shall not be subject to these buffer requirements.
9. 
Seismic Hazard Areas. Structural development proposals shall meet all applicable provisions of the International Building Code.
The city shall evaluate documentation submitted including the site assessment report, and condition permit approvals to minimize the risk on both the subject property and affected adjacent properties. All conditions on approvals shall be based on known, available, and reasonable methods of prevention, control and treatment. Evaluation of geotechnical reports may also constitute grounds for denial of the proposal.
B. 
Alterations of the Buffer and/or Geologically Hazardous Area. Alterations of the buffer and/or geologically hazardous area may occur for development meeting the following criteria:
1. 
No reasonable alternative exists; and
2. 
A site assessment report is submitted and certifies that:
a. 
There is a minimal hazard as proven by evidence of no landslide activity in the past in the vicinity of the proposed development and a qualitative analysis of slope stability indicates no significant risk to the development proposal and adjacent properties; or the geologically hazardous area can be modified or the development proposal can be designed so that the hazard is eliminated or mitigated so that the site is as safe as a site without a geologically hazardous area;
b. 
The development will not significantly increase surface water discharge or sedimentation to adjacent properties beyond predevelopment conditions;
c. 
The development will not decrease slope stability on adjacent properties; and
d. 
Such alterations will not adversely impact other critical areas.
C. 
Noncompliance and Failed Mitigation Plans.
1. 
Projects found to be in noncompliance with the mitigation conditions issued as part of the development approval are subject to enforcement actions necessary to bring the development into compliance with this chapter.
2. 
Mitigation plans which do not fulfill the performance required based on the site assessment/geotechnical report findings or otherwise fail to meet the intent of this chapter shall be revised and the subject development brought into compliance with the revised mitigation plan.
3. 
Mitigation Plan Certification. Upon completion of the project, a qualified professional shall certify that the mitigation plan has been properly implemented. The certification shall be required prior to final approval of the project by the director.
(Ord. 1853 § 2 (Exh. B), 2018; Ord. 1933 § 1 (Exh. A), 2023)