Geologic Planning

five geologist standing atop a vantage point looking at a sand and gravel pit below

Geologic planning involves cooperation between a variety of stakeholders. Geologists, land-use planners, emergency management staff, and others work together to map mineral resource lands, recognize the importance of climate change, identify natural hazards, and mitigate the impacts of these natural hazards on communities.

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What is geologic planning and why have it at WGS?

Washington Geological Survey (WGS) scientists are experts in Washington State geology, and our research touches on many aspects of geology including geologic hazards, mineral resources, and climate resilience. All of these topics are relevant for society, and our work contributes to the safety and economic well-being of Washington’s residents. We provide reports, maps, and other geologic products, and engage in outreach to support decision-making across multiple levels of government within Washington State.

WGS has established a Geologic Planning Liaison position to more effectively connect science at WGS with other state agencies, local jurisdictions, and tribes. The Geologic Planning Liaison works with planners, geologists, and other professionals in local, state, and tribal jurisdictions across Washington. By gathering feedback and providing guidance and resources, we hope to better understand local decision-making and improve communication between WGS and these entities. This sharing of information helps build resilient communities.

venn diagram of risk, showing that risk is influenced by the hazard itself, the value of people and property, and the vulnerability of those people and property to the hazard

This diagram shows how risk is influenced by the hazard itself, the value of people and property, and the vulnerability of those people and property to the hazard.

In Washington State, the most significant geological hazards are earthquakes, tsunamis, volcanic events, and landslides. Other geologic hazards include subsidence above improperly reclaimed mines and exposure to hazardous minerals like radon. Climate change and human alteration of the environment exacerbate the impacts of natural hazards on people, property, and infrastructure, increasing the need for hazard identification and efforts to minimize risk and mitigate impacts.

Geologic planning and growth management

  • Growth Management Act
  • Critical areas and best available science
  • Mineral resource lands
  • Communities grow and change over time. This growth introduces issues such as increased population, aging and overburdened infrastructure, increased traffic congestion, pollution, school overcrowding, urban sprawl, a loss of resource lands, and a loss of rural character.

    In response to these issues, the Washington Growth Management Act (GMA) was adopted in 1990. The GMA is codified in the Revised Code of Washington (RCW 30.70A) and in the Washington Administrative Code (WAC) in several chapters identified in this webpage. The GMA is written to provide common goals and requirements in land-use planning to address problems with uncoordinated and unplanned growth across Washington and to protect natural resources.

    The GMA requires local governments to adopt comprehensive plans and development regulations to guide future growth and development. Comprehensive plans and development regulations help shape land-use, natural hazards mitigation, emergency management, and other decisions that take into account factors such as, but not limited to, geologic hazard locations.

    Local governments must complete periodic updates to ensure their plans and regulations address new legislation, emerging issues, and community needs. For more details on GMA requirements and goals, check out the Department of Commerce’s Growth Management Act webpage, and the provisions of the RCW and the WAC noted throughout this webpage.

    map showing counties in Washington and the dates when they need to have updates to their GMA plans

    The map shows the periodic update schedule for each county in Washington. The color code indicates the year the periodic update is due for that county and the cities within. In 2024, the due date is December 31. In 2025, 2026, and 2027, the due date is June 30. The 11 starred counties are subject to critical areas and natural resources lands requirements only. This graphic is modified with permission from the Washington State Department of Commerce.

    There are at least three key areas in the GMA that WGS can provide more collaboration and technical assistance on: critical areas (which contain geologically hazardous areas), best available science, and mineral resource lands.

  • The GMA requires all cities and counties to adopt development regulations that protect critical areas. These regulations help to preserve the natural environment, maintain fish and wildlife habitat, and protect drinking water. Protecting critical areas also helps reduce exposure to risks of natural hazards, such as landslides or flooding, and maintains the natural elements of our landscape. It can be costly, or even impossible, to replace critical area functions and values once they are lost.

    photo of Chester Morse Lake, with rocks and fall-colored bushes in the foreground, the lake in the middle, and Mount Rainier in the background

    Image of Chester Morse Lake, part of the City of Seattle's Cedar River Municipal Watershed that supplies drinking water to 1.5 million people in Seattle. Drinking water areas are typically protected as part of critical areas. Photo by Maria Furtney, WGS/DNR.

    As defined by RCW 36.70A.030 (6) the five types of critical areas are:

    • Wetlands
    • Areas with a critical recharging effect on aquifers used for potable water
    • Frequently flooded areas
    • Geologically hazardous areas
    • Fish and wildlife habitat conservation areas

    The GMA further requires that all critical areas must be designated, and their functions and values protected using the best available scientific information—known as ‘best available science’.

    As defined by WAC 365-190-120, in subsection (3), geologically hazardous areas are areas that are susceptible to one or more of the following types of hazards:

    1. Erosion hazard
    2. Landslide hazard
    3. Seismic hazard
    4. Areas subject to other geological events such as coal mine hazards and volcanic hazards, including: Mass wasting, debris flows, rock falls, and differential settlement

    In subsection (4), the WAC 365-190-120 states that counties and cities should assess the risks and classify geologically hazardous areas as either:

    1. Known or suspected risk;
    2. No known risk; or
    3. Risk unknown—data are not available to determine the presence or absence of risk

    As described by the WAC 365-196-830 for 'Protection of critical areas', the GMA “requires the designation of critical areas and the adoption of regulations for the protection of such areas by all counties and cities, including those that do not plan under RCW 36.70A.040.”

    The GMA has provisions for both fully and partially planning counties.

    • Under GMA provisions there are 18 counties that are currently “fully planning” and required to comply with all provisions of the GMA (see RCW 36.70A.040(1))
    • There are 10 counties that have chosen to “opt-in” to become GMA fully planning (see RCW 36.70A.040(5))
    • There are 11 counties that do not plan under RCW 36.70A.040, but must comply with some GMA requirements. Specifically, these counties and cities must adopt development regulations that designate and protect critical areas and designate natural resource lands. These counties are frequently labelled “partially planning” (see RCW 36.70A.060 and RCW 36.70A.170)

    For more information about which counties and cities have different kinds of requirements, contact the Department of Commerce’s Growth Management Staff or their website, Washington State Department of Commerce Growth Management.

    graphic of person with a helmet holding a rolled up paper

    The Department of Commerce responded to the Legislature’s direction in 1990 to develop minimum guidelines to guide the classification of agricultural lands, forestlands, mineral resource lands and critical areas. The Minimum Guidelines in WAC 365-190 are minimum requirements for critical areas classification and designation. They reference the statutory requirement to include best available science, and recommend that counties and cities designate critical areas using maps, definitions, and standards. To read more about designation and protecting critical areas, see the Department of Commerce's Critical Areas Handbook.

    Local governments must identify, collect, and assess the available scientific information relating to the protection of critical areas within their jurisdiction, and then determine which of that science constitutes the “best available science.” Local governments may accept or solicit scientific information from state and federal agencies, universities, tribes, subject-matter experts, and others. But the burden ultimately is on the local government to determine whether the scientific information assembled in fact constitutes the best available science.

  • The GMA requires that counties and cities identify and classify mineral resource lands. According to WAC 365-190-070, mineral resources are sand, gravel, and valuable metallic substances. Other minerals may be classified as appropriate. When counties and cities know what mineral resources are there and where they are located, they can better protect them and plan for growth.

    As described in WAC 365-190-070: counties and cities are required to identify and classify areas that contain minerals that can be obtained as resources. These areas are known as mineral resource lands. Counties and cities are further required to consider their long-term needs for these areas and to plan to conserve these resources for future uses.

    graphic of person with a helmet holding a rolled up paper

    The WAC specifically states that counties and cities should, at a minimum, focus on lands that contain the following resources: sand, gravel, and valuable metallic substances. To be certain that counties and cities have the best possible science when identifying and classifying these mineral resource areas, they should use maps and information on location and extent of the mineral deposits provided by the Department of Natural Resources, the U.S. Geological Survey, and any other relevant information provided by property owners.

    For more information on aggregate resources, see the WGS Aggregate Resources webpage which includes the Aggregate Resource Mapping in Washington information sheet.

    five geologist standing atop a vantage point looking at a sand and gravel pit below

    WGS geologists overlooking a sand and gravel pit in Pierce County. Photo by Dan Coe, WGS/DNR.

Where WGS contributes to GMA critical areas and planning

The Geologic Planning Liaison plays an essential role in sharing WGS resources with agencies and jurisdictions, and in understanding agency and jurisdiction needs to better inform future WGS science. Our outreach and communication will be more comprehensive across the state, and be more specifically targeted to address individual jurisdictional and agency needs. The Geologic Planning Liaison works with staff from the Department of Commerce to help local jurisdictions access and use our science to inform policy decisions. With that in mind, we note below some of the specific areas where WGS contributes and can help local jurisdictions achieve their goals related to the GMA and land-use planning.

  • Geologically hazardous areas WAC 365-190-120: Erosion, Landslide Hazards, Seismic Hazards, Volcanoes, Tsunamis
  • Mineral resource lands WAC 365-190-070: Sand, gravel, and metallic mineral resources
  • Best available science WAC 365-195: What it is and how to obtain it
  • Climate Commitment Act Implementation
How can WGS geologic planning help you?
  • Provide the best available science for many geologic hazards.
  • Discuss the appropriate uses of our data and maps.
  • Provide assistance with communication for local outreach about WGS science.
  • Provide examples of land-use codes, outreach, and tools used by other jurisdictions.
  • Review land-use codes related to geologic hazards.
  • Assist with GMA periodic updates. For example, by identifying the best available science for geologically hazardous areas, reviewing proposed comprehensive plan language, and providing tools for integration of scientific information into implementation provisions.
Sample projects that the geologic planning liaison collaborates with WGS scientists on