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Geologically Hazardous Area Code Amendments

Geologically Hazardous Area
Code Amendments

Kirkland Zoning Code Chapter 85
(Critical Areas: Geologically Hazardous Areas)
File No. CAM17-00681

Project Location: 
Citywide

Project Description:

The City has begun the process to develop code amendments to the text of the Kirkland Zoning Code Chapter 85 (Critical Areas: Geologically Hazardous Areas).   Staff will use Best available science (BAS), and has used the latest technology (LiDarlinks to external site) to update the maps that exhibit places that may present landslide or seismic hazard risks.  Throughout the code amendment process, issues presented by City staff, its technical experts (Associated Earth Science Inc.), citizens and the development community will be explored.

Project Update:

- The Kirkland City Council held a study session (PDF 1.2MB) on November 21, 2017, where they received a presentation on Kirkland’s Geology and updated Geologically Hazardous Area maps.The Council was also briefed on the code amendment process and the Office of Emergency Management discussed how the updated maps will be used by first responders.
- Public Lecture – December 11, 2017 - Kathy Troost, UW Department of Earth Space and Science will present on Kirkland’s Geology and the updated Geologically Hazardous Area maps.  A video stream of this presentationlinks to external site (4.7GB) is available on KirklandTv.
- Public Lecture - December 11, 2017 - Kathy Troost, UW Department of Earth Space and Science
- Joint Planning Commission (PC)/Houghton Community Council (HCC) Study Session #1 - January 11, 2018 at 7pm
- PC Study Session - Planning Commission Study Session #2 - February 22, 2018 at 7pm
- City Council Adoption of Code Amendments - (to be determined) April/May 2018

Updated Maps:

Landslide Susceptibility Map description:
The map of landslide susceptibility (PDF 12MB) is the composite product of a 3-part landslide hazard product which consists of a landslide inventory, a shallow landslide hazard model, and a deep-seated landslide hazard model.  The map, a representation of the landslide inventory and models, includes polygons showing the locations of landslide head scarps, polygons of landslide deposits, polygons of susceptible geologic materials and contacts, buffers, and a factor-of-safety based representation of landslide susceptibility ranked from low to high. The landslide features were identified using: geomorphic analyses of LiDAR data, field observations, subsurface data from exploration logs in geotechnical documents, and information from City of Kirkland staff.  The City has created this document (PDF 120KB) providing more information about the data collected in the production of this map.

Liquefaction Potential Map description:
Liquefaction Potential Map (PDF 10.2MB) description:The liquefaction potential map consists of a qualitative assessment of the potential of geologic materials to liquefy during loading such as from earthquake shaking. Refer to the Seismic Hazards Map for information about the tectonic setting and potential for earthquakes to impact the City of Kirkland. The map includes polygons showing three categories of liquefaction potential based on a weighted matrix of geologic parameters including, grain size, age of deposit, density from standard penetration tests, and depth to groundwater. Areas of modified land (either filled and/or graded), provided as a separate layer, should always be included on the map because they significantly impact the liquefaction potential. The geologic units were determined using: geomorphic analyses of LiDAR data; field observations in excavations, gullies, and road cuts; subsurface data from exploration logs in geotechnical documents; and geologic principles. The City has created this document (PDF 81KB) providing more information about the data collected in the production of this map.

Planning & Building Department
123 5th Avenue, Kirkland WA 98033

General Inquiries:
Building Questions
Building_Services@kirklandwa.gov
Planning Questions
PlanningInfo@kirklandwa.gov
T. 425.587.3600 | F. 425.587.3232