Columbia Corridor and Industrial Lands Ezone Project documents

Environmental overlay zones (ezones) are a tool used by the City of Portland to protect important natural features such as rivers, streams, wetlands and vegetation. These features provide important benefits such as water quality improvements, stormwater management, and wildlife habitat.  

In the Columbia Corridor and Industrial Lands Environmental Overlay Project (CCIL Ezone Project) area, there are two types of ezones – Environmental Conversation (c zone) and Environmental Protection (p zone). The c zone is applied to natural features that are important but where some environmentally sensitive development may be permitted. The p zone is applied to the most critical features, where development should be avoided except under special circumstances.

View full size image of A graphic that demonstrates the difference between environmental protection zones and environmental conservation zones

In both ezones, existing development can be operated, maintained and, in many cases, replaced. New development and expansion of existing development is subject to ezone requirements.

Volume 1: Policy, Natural Resource Inventory, and Resource Protection Decisions

This volume provides background information about the project, explains the project methodology, and describes the state-mandated economic, social, environmental, and energy (ESEE) analysis that was used to develop the Proposed Draft ezones.

Volume 2: Natural Resource Protection Plans

This volume is divided into three area-specific natural resource protection plan documents: Volume 2A, 2B, and 2C. Each of these documents focuses on a different portion of the CCIL Ezone Project area and includes an inventory of the natural resources and location-specific natural resource protection decisions.

Volume 3: Zoning code amendments

This volume includes amendments to the environmental overlay zone chapters in the zoning code. Amendments are grouped into the following six categories:

1. Regulatory Relief and Streamlining
2. Floodplain Development Requirements
3. Response to Emerald Ash Borer
4. Lighting Regulations in the Environmental Zones
5. Standards for Right-of-Way Improvements
6. Miscellaneous Technical Amendments and Clarifications.

Ezones in the project area were originally applied as part of more than a dozen area-specific natural resource protection plans. The earliest of these plans were adopted in the late 1980s and early 1990s. Some of these old plans have never been updated. 

The CCIL Ezone Project provides the opportunity to revisit the environmental protection decisions of those previous plans to ensure that environmental resources in the project area are protected moving forward, while taking into consideration the potential implications of those decisions on future economic development. 

Technology has improved significantly since the adoption of existing plans in the project area. Natural resources are mapped more accurately than in the past. We now know that the first ezone mapping efforts missed some significant natural features.

There is an identified need for buildable industrial land to help meet Portland's long-term job growth. At the same time, it is important that ezones are accurately applied on and around important natural features, including in the industrial corridor around the Columbia Slough. The Columbia Corridor Industrial Lands project is working in coordination with the Economic Opportunities Analysis to ensure that there will be enough industrial land supply to meet expected job growth. 

The Proposed Draft ezone application is not anticipated to result in significant barriers to development for most sites. Up to 45 percent of draft p zones are located within the banks of waterbodies, or areas that are otherwise difficult to build, such as steep slopes. The project team will continue to coordinate with property owners to ensure that natural resources are mapped correctly to inform the application of ezones.

Ezones have exemptions that apply to existing development and operations. Ezone expansions or additions will not prevent continued operations and maintenance of existing uses, such as buildings, parking lots, and other infrastructure.

Within ezones, the removal of native trees, including Oregon ash trees, is regulated and limited. In September of 2025, an invasive insect known as the Emerald Ash Borer was found in Portland. This insect is capable of infesting and killing North American species of ash trees, and it has spread rapidly in other parts of the country.

This project updates standards that apply to ezones throughout the city to allow for the removal and replacement of Oregon ash trees with other native trees that are not susceptible to the Emerald Ash Borer. These standards also prevent the planting of additional Oregon ash trees. These steps are a part of the City's Emerald Ash Borer Response Plan.

In 2016, the National Marine Fisheries Service issued a Biological Opinion on the Federal Emergency Management Agency's (FEMA) National Flood Insurance Program. The Biological Opinion concluded that floodplain development enabled by the program impacts 16 threatened or endangered fish species in Oregon. The Biological Opinion directed FEMA to modify its requirements to preserve habitat and storage for flood waters when development occurs in the floodplain.

To comply with the Biological Opinion, this project incorporates new mitigation requirements for development proposed in floodplains nearest to the Columbia River and Lower Columbia Slough. These updates are a part of a multi-phase process that the City has been taking to incorporate the directives of the Biological Opinion to floodplains throughout the city.

The Columbia South Shore Plan District (zoning code chapter 33.515) requirements apply to portions of the Columbia Corridor that are east of Interstate 205. The environmental requirements of the Plan District were originally adopted in 1987 and were written in preparation for future industrial development on farmland within the area. Most of that industrial development has occurred and the regulations are generally less relevant to existing development patterns. Additionally, the structure and processes of the environmental requirements of the Plan District are inconsistent with the approach used in other ezones and are generally cumbersome and difficult to implement.  

Applying the requirements of the Environmental Zones chapter (33.430) to this area instead of the existing Plan District environmental regulations will simplify the code and the permitting process. As a part of this proposal, staff have taken steps to preserve the intent of the Plan District.