Planning for natural hazards,
Protecting natural resources and communities

Winterbrook Planning has pioneered a comprehensive, forward thinking, and integrated approach to Urban Growth Boundaries (UGBs) and Oregon Land Use Planning Goals 5 and 7.

The approach has been used successfully in cities across the region.

  • City of Albany
  • City of Beaverton
  • City of Corvallis
  • Clackamas County Urban Area
  • Columbia County
  • City of Damascus
  • City of Eugene
  • City of Hillsboro
  • Hood River County
  • Island City
  • Junction City
  • City of Lake Oswego
  • Lane County
  • Marion County
  • City of McMinnville
  • City of Medford
  • City of Molalla
  • Multnomah County
  • Multnomah Channel & Sauvie Island
  • City of Pendleton
  • City of Portland
  • City of Prineville
  • City of Sandy
  • City of Scappoose
  • City of Springfield
  • City of St. Helens
  • City of The Dalles
  • City of Tigard
  • City of Troutdale
  • City of Tualatin
  • Washinton County
  • City of West Linn
  • Wallowa County
  • City of Woodburn
  • Metro
  • Oregon Department of State Lands

Goal 5 is a broad statewide planning goal that covers more than a dozen resources. The resources range from wildlife habitat, to historic places, and gravel mines. To protect and plan for them, local governments are asked to create a number of inventories. The inventories in a local plan may address only a portion of the resources included in Goal 5.

Goal 7 requires local comprehensive plans to address Oregon’s natural hazards. Protecting people and property from natural hazards requires knowledge, planning, coordination, and education.


Urban Growth Boundary and the Integrated Goal 5 and 7 Program


In this White Paper, Winterbrook recommended using GIS mapping technology and available state and local information to create a series of overlay maps that show the relationships that exist among Statewide Planning Goal 7 Natural Hazards (Flooding, Slope and Landslide, Earthquake Liquefaction and Shaking, and Wildfire) and Goal 5 Natural Resources (Wetlands, Riparian Corridors and Upland Forests).  Based on this information, Winterbrook recommended an integrated management approach consistent with statewide planning requirements, objective ranking of composite functions and values, and local policy preferences. This information is valuable for conducting buildable lands inventories and evaluating trade-offs between urban development and natural features management objectives.

Tree Grove C5


Winterbrook prepared the McMinnville Natural Hazards Inventory for land within and surrounding the existing UGB. The inventory was based on the GIS data available in statewide inventories, the Yamhill County Natural Hazards Mitigation Plan, and the draft McMinnville Natural Hazards Mitigation Plan. Winterbrook worked with city planning staff to create an integrated ranking system that provided an objective basis for mapping low, moderate and high hazard areas. Winterbrook relied on hazard maps available on DOGAMI’s (Oregon Department of Geology and Mineral Industries) Statewide Geohazards Viewer to map and rank geological, wildfire and flood hazards within the entire study area.

Based on this analysis, Winterbrook prepared draft Comprehensive Plan policies for managing development in mapped flood, steep slope, landslide, earthquake (liquefaction and shaking) and wildfire hazard areas consistent with other city planning objectives.

In 2020, the city used Winterbrook maps to evaluate alternative UGB expansion areas, consistent with Goal 7 Natural Hazards and Goal 14 Urbanization. As a result, the city eliminated steeply sloped and forested land in the West Hills to avoid mapped geological and wildfire hazard areas. The UGB expansion was approved by the Land Conservation and Development Commission and supported by local and state advocacy groups.


Starting with the 2019 urban growth boundary, our study on natural hazards went out a further 1.5 miles to gain perspective on how the future development could avoid natural hazards and protect the resources of the expanding city.


McMinnville’s West Hills are characterized by slide-prone steep slopes that are even more likely to fail in a major subduction earthquake, wildfire hazard areas, scenic views and viewpoints, wooded areas (with wildlife habitat) and wetlands (along stream corridors and at the base of hillsides).


McMinnville steep slopes hazards

Steep slopes west of McMinnville


Landslide, liquefaction, subduction shaking, and steep slopes were mapped and taken into account when the overlay and subsequent protection and mitigation programs are formed. 


McMinnville steep slopes hazards


Winterbrook relied on flood hazard maps available on DOGAMI’s (Oregon Department of Geology and Mineral Industries) Statewide Geohazards Viewer found in the McMinnville NHMP. Flood hazards within the study area are associated with Cozine Creek, Berry Creek, Baker Creek and the Yamhill River.


Building on work completed in 2020, Winterbrook prepared an Integrated Natural Features Inventory based on GIS mapping that included both Goal 5 (riparian corridors, upland forests (tree groves) and scenic) resources and Goal 7 natural hazards for all land within the recently adopted UGB.
Based on “Great Neighborhood Principles” that provide the policy foundation for the McMinnville Comprehensive Plan, Winterbrook recommended a new Comprehensive Plan Chapter XI Natural Features management program that recognizes the substantial overlaps among significant natural resources and moderate to severe natural hazard areas. Winterbrook also prepared a series of overlay zones to implement Great Neighborhood Principles and the Natural Features policies.

The recommended program recognized that natural resources (riparian corridors, tree groves, scenic areas) are protected by measures designed to limit development in mapped natural hazard areas (floodplains, geological, and wildfire). The program also relied on Goal 5 safe harbor provisions to inventory and protect riparian corridors. Through this process, Winterbrook was able to identify natural resource areas outside of protected natural hazard areas and riparian corridors that require a more detailed Goal 5 ESEE (economic, social, environmental and energy) consequences analysis. Notably, the management program encourages residential density transfer from protected natural features to building land, and the replacement and construction of public facilities in areas with protected natural features.


By identifying and inventorying significant tree groves within the UGB, the subsequent ESEE and protection program process for these groves could be completed in conjunction with the UGB amendment process.


The Goal 5 rule allows “safe harbors” – or prescribed protection programs – for significant wetlands and riparian corridors. If a local government chooses to apply safe harbor protection to a wetland or riparian corridor site, then an ESEE analysis is not required.


The Great Neighborhood Principles call for equitable access to community amenities such as scenic views and viewpoints. Views of the West Hills from various lower-elevation City viewpoints are an asset for McMinnville residents and visitors, as are viewpoints of McMinnville and surrounding farmlands from above. Both views and viewpoints provide opportunities for equitable scenic enjoyment.