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Shoreland Processes and Hazards
Introduction
Oregon’s dramatic and beautiful coast line is the result of dynamic, powerful natural forces of weather, climate, ocean waves and currents, and the Earth’s own tectonic evolution.  These forces continually shape the coast, creating an environment that is at once attractive and dangerous.  Development on the Oregon coast largely occupies the available less hazardous sites.  New development is increasingly proposed for more hazardous areas subject to Nature’s forces such as steep slopes, ocean bluffs, landslide-prone sites, and low-lying areas subject to ocean flooding and coastal erosion.  People may later purchase or occupy these developments with no knowledge of the hazard risk.

In addition, scientists are continually refining their understanding of the potentiRiprap at Neskowinally catastrophic forces of earthquakes and tsunamis as well as the more gradual effects of climate change.  The vulnerability of coastal communities to chronic and catastrophic forces as well as climate change is a concern to those who live, work, and recreate in those communities and to public officials responsible for community safety and well-being.

Oregon’s statewide land use planning program require local governments to plan for and make decisions that account for hazards known to be present in this active, dynamic environment.  This website is intended to provide information about the state’s requirements for coastal hazard planning and serve as a gateway to more information about the hazards themselves.
Photo by Armand Thibault

What are Coastal Hazards?
There are two general categories of coastal hazards.
 
One, catastrophic hazards are regional in scale and scope such as the massive Cascadia Subduction Zone earthquakes that occur every 300-1000 years, with consequent severe ground shaking, subsidence, landsliding, liquefaction, and tsunamis.  Catastrophic events are inherently difficult to predict and have only recently become a principal concern for coastal communities. 
The second kind, chronic hazards, are more local in occurrence and impact, are usually present over the course of a year, and may result in damage to life and property that, although sometimes dramatic, is limited in scope and severity.  Chronic hazards include river and ocean flooding from storms, bluff and beach erosion, landslides on steep slopes, or windstorms.  The wide distribution and frequent occurrence of chronic hazards makes them a more immediate concern. 
 
Significant information and data are available for chronic and catastrophic hazard risks that will enable coastal communities, public agencies, and citizens to better plan for both chronic and catastrophic coastal hazards.


Planning and Regulation
Cities and counties are required to account for areas with natural hazards in comprehensive plans and associated ordinances. On the coast, planning for coastal hazards is guided by Statewide Planning Goal 17, Coastal Shorelands, and Goal 18, Beaches and Dunes.  These goals require local governments to identify and plan for the dynamic and potentially hazardous nature of coastal shorelands, particularly along the ocean.

Goal 17: Coastal Shorelands
The purpose of Goal 17 (pdf) is "to conserve, protect, develop, and, where appropriate, restore the resources and benefits of all coastal shorelands." In addition to its conservation objectives for protecting various shoreland habitats, Goal 17 aims to reduce hazard to human life and property. Local governments are required to identify the location of areas subject to geologic and hydrologic hazards within the Coastal Shorelands planning area.
 
Local governments are required to delineate a Coastal Shoreland planning area that includes lands subject to ocean flooding and within 100' of the ocean shore or within 50' of an estuary or coastal lake, and adjacent to areas of geologic instability related to or impacting a coastal water body.


Goal 18: Beaches and Dunes
Dune scarpGoal 18 (pdf) is designed "to conserve, protect, where appropriate develop, and, where appropriate, restore the resources and benefits of coastal beach and dune areas." The goal also aims to reduce the hazard to human life and property from natural or human-induced actions associated with these areas.
 
Areas subject to Goal 18 include beaches, active dune forms, recently stabilized dune forms, older stabilized dune forms and interdune forms. Uses shall be based on the capabilities and limitations of beach and dune areas to sustain different levels of use or development, and the need to protect areas of critical environmental concern, areas having scenic, scientific, or biological importance, and significant wildlife habitat as identified through application of Goal 5 (Natural Resources) and Goal 17 (Coastal Shorelands).
 
Local governments are required to inventory beaches and dunes and describe the stability, movement, groundwater resource, hazards and values of the beach, dune, and interdune areas.  Local governments must then apply appropriate beach and dune policies for use.

Ocean Shore Regulation
Oregon's ocean beaches are managed by the Oregon Parks and Recreation Department [OPRD] which has an extensive permitting program for shoreline protection underRiprap repair at Neskowin The Ocean Shore Law [ORS 390.605 – 390.770], also known as the "Beach Bill." OPRD regulates activities affecting the ocean shorelands west of the statutory vegetation line, the survey line, or the line of established vegetation which is most landward, including beachfront protective structures, stairways, or other structures than impinge on the public beach.  The OPRD has incorporated the Department of State Lands authority to regulate removal and fill activities along the ocean shore under its permit program. Permitted activities must be consistent with the Statewide Planning Goals (especially Goal 18), corresponding provisions of local comprehensive plans, and with the OPRD Ocean Shores Management Plan.
Photo by Armand Thibault

Tsunami Inundation Zones
Although they happen infrequently, tsunamis generated by large earth movements in the Pacific Ocean are a serious threat to the Oregon coast.  The Department of Geology and Mineral Industries [DOGAMI] has mapped tsunami inundation zones in coastal communities pursuant to ORS 516.090. The maps are used by local governments to identify evacuation routes and areas where the development of certain critical and essential facilities and major structures are restricted, in accordance with ORS 455.446 and .447. There are exemptions for existing facilities and water dependent development as well as exemptions for certain facilities based on need for strategic location or school district boundaries. Local governments have worked with DOGAMI to create maps and develop evacuation routes.
 
DOGAMI is developing more detailed and accurate tsunami risk maps based on geologic evidence for repeated subsidence events along the Oregon coast and analysis of the effects of the December 26, 2004, tsunami in Indonesia.  This work has generally shown increased tsunami risks along the Oregon coast due to higher potential wave run up.

Coastal Management Program Activities
A principal mission of the Oregon Coastal Management Program is to help local governments do a better job of planning for coastal hazards.  The OCMP provides funds cities and counties to acquire better data and analysis of coastal processes, and to improve hazard policies and education.  A key reference for this work is "Improving Natural Hazards Management on the Oregon Coast" [available from Oregon Sea Grant Publications [.pdf - 3.8 MB] [HTML - 319 KB]].  The OCMP also works closely with the Oregon Department of Geology and Mineral Industries to provide accurate scientifically-based information.

Assessing Coastal Hazards
Coastal Hazard Risk Maps
The Oregon Department of Geology and Mineral Industries (DOGAMI) has completed detailed coastal erosion and hazard maps and analyses for the ocean shores of Clatsop, Tillamook, Lincoln, and portions of Curry and Coos Counties.  Each County should have these reports and maps available for review or they can be purchased from DOGAMI.  The DOGAMI maps, overlaid on aerial photos, delineate areas of Active, High, Moderate, or Low hazard risk on the ocean shore. Risk zones account for topography, ocean processes and sediment transport that cause erosion of bluff-backed and dune-backed environments.  The DLCD Coastal Program has developed a model ordinance (doc or pdf) for local governments that can be used in conjunction with the DOGAMI risk zone maps. 
 
Beach monitoring and Mapping
The DOGAMI carries out a "Oregon Beach and Shoreline Mapping and Analysis Program ” to document the spatial variability of beach change at various time-scales (i.e. seasonal, multi-year and long-term changes). The program purpose is to provide high-quality scientific information about changes to the shore and beach that can be used by coastal managers, city and county planners, the geotechnical community and the public-at-large to plan for ocean shoreline change.  This program is central to state efforts to understand the effects (erosion or accretion) of future storms, impacts from El Niños, and to predict long-term change.

Managing for Coastal Hazards
Statewide Goal 18 Shoreline Protection Structure Eligibility Tool
Goal 18 limits construction of shoreline protective structures to development that existed prior to January 1, 1977. Because it is often difficult to determine whether a property was “developed” at that time, the DLCD has developed a GIS-based tool to help local governments determine whether a parcel is eligible for shorefront protection.  The tool is available for most of the Oregon coast; only ocean shores of Coos, Curry and Douglas counties remain.  
 
A Model Code for Chronic Coastal Hazards
The DLCD is in the process of preparing a model ordinance in an effort to assist local governments to address chronic coastal hazards. The Department is hopeful that the model ordinance could be designed to be used in conjunction with DOGAMI hazard risk zone maps.  The risk zones, including active, high, moderate, and low, are used to identify risk areas and the model code would provide options for uses within these risk areas. The code would consider options for addressing existing lots or parcels, land divisions, vegetation removal, excavation and fill, and hazard disclosure and liability waiver.  In addition, the model code would provide a section and options for addressing Goal 18 beach and dune prohibition areas.  We hope that a model code of this type would provide an innovative option for coastal hazards management within chronic coastal hazard erosion areas.  Please contact Laren Woolley, Coastal Shores Specialist, for further information.

Interagency Planning
The DLCD co-chairs the interagency "Coastal Processes and Hazards Working Group" (CPHWG) that focuses on shoreline hazards, threats to public facilities, and changing conditions due to climate change and sea level rise.  The CPHWG is a coordination and outreach mechanism for local, state, and federal agencies, industry, and interest groups to share information across programs and projects.  The CPHWG has produced two geologic guideline documents related to new development on oceanfront properties, and shoreline protection structures. 

Assessing Shoreline Conditions
DLCD also offers Coastal Hazards Alleviation Techniques [ACHAT] (pdf) that is applicable to the Oregon coast and was prepared for use by local governments in assessing natural hazards mitigation options.

Littoral Cell Planning
Littoral cell mapSediment transport and the erosion or accretion of beaches are controlled by the configuration of each of the many littoral cells along the Oregon coast. These cells, bounded by rocky headlands on either end, appear to have a relatively fixed sand budget that may move within the cell but is rarely lost. 

For nearly two decades the DLCD has promoted littoral cell planning as a key to successfully recognizing and accounting for risk from hazards along the ocean shore. A littoral cell management plan is a comprehensive, integrated, area-wide hazard management strategy that accounts for geology, sediment characteristics and volume, length, riverine inputs, presence of dunes or bluffs and the unique characteristics of each cell. These plans are focused on reducing risk to new and existing oceanfront development and include geologic inventories, a chronic hazards management strategy, and implementing mechanisms.

Educating the Public and Property Owners
The DLCD and its partners conduct coastal hazard education and outreach efforts for the full range of chronic and catastrophic coastal hazards. Outreach techniques include publications, regional and local workshops, and video.  The DLCD and Oregon Sea Grant produced a DVD video called "Living on the Edge, Buying and Building Property on the Oregon Coast".

Future Work
There is much to be done to reduce the hazard to development and to lives on the Oregon coast.  Some work anticipated over the next few years includes:

FEMA Map Revisions:  FEMA maps showing coastal flooding risk have been very helpful in identifying areas of risk.  However, current maps did not utilize the most accurate models in determining coastal flooding hazards in the Pacific Northwest.  FEMA will be working with DOGAMI, DLCD and others over the next several years to develop revised maps and analyses.

Adaptation Planning:  The Coastal Program in DLCD will be expanding efforts to help local governments and communities to identify and adapt to the effects of climate change such as sea level rise, increasing storm intensities, and increasing wave heights.

Outreach and Education:  DLCD staff will continue to work with individual cities and counties to increase understanding of coastal hazards and assist in utilizing all available tools in managing development in coastal areas.

Hazard and beach monitoring and mapping:  The DOGAMI will increase ocean shore monitoring and mapping to fill knowledge gaps and enhance its data base for future decision making efforts.

Shoreline Protective Structure Inventory Work:  DLCD will complete all draft inventories and work with local governments to adopt and using these them.

Additional Resources
Listed here are contacts, programs, and documents to assist planners, local governments and citizens in obtaining further information on coastal hazards.