About the Ezones Map Correction Project

2 photos side by side: a blue heron, and a woman and toddler in a field of wildflowers
Purpose, background, timeline, and contact information for the Ezones Map Correction project.
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Project purpose

The purpose of the Environmental Overlay Zone Map Correction project is to synchronize the location of the overlay zones with the location of existing natural resources identified in the Natural Resources Inventory (NRI). This is part of bringing the zoning code into compliance with the 2035 Comprehensive Plan and ensures resources across Portland are mapped accurately and are regulated in a consistent way.

Project background

Beginning in 1989, Portland adopted natural resource conservation plans for areas in the city where there are significant natural resources. Following a process laid out by Oregon State Land Use Planning Goal 5, environmental overlay zones have been applied to protect streams, wetlands, forests, steep slopes and wildlife habitat. By 2002, environmental overlay zones had been applied to resources throughout all of Portland.

black and white topographical map with streams shown in blue

In the early 1990s, the City’s environmental overlay zones were applied using relatively “low-tech” methods. Today, technology has advanced significantly and can help us identify and better map natural resources. For example, LiDAR is a remote sensing tool that detects light reflected off objects on the ground. LiDAR can be used to accurately and consistently map topography, streams, wetlands and vegetation – even the height of individual trees.

Using this new technology, the City updated maps of Portland’s natural resources. Over 160 miles of streams were remapped and approximately 75 miles of previously unmapped streams were added. The new data was documented in the Natural Resources Inventory (NRI) and adopted by City Council in 2012.

The updated NRI revealed discrepancies between the environmental overlay zone boundaries and the location of resources those overlay zones were intended to protect. This means the environmental overlay zones need to be updated. The work will be done by taking the new NRI data showing where natural resources are located and adjusting the environmental overlay zone boundaries to match.

The first step is to make sure the natural resources are mapped correctly.

A satellite map showing a stream, with a part of it highlighted, that is under consideration for e-zones.

Is the Ezone Project intended to prevent development in my neighborhood? Is it opening up new areas for development?

The Ezone Project is a map correction project. The project is using a methodology that is consistent with the policy that was adopted when the original Ezones were created in 13 different area-specific natural resource protection plans between 1990 and 2003. It is correcting the location of the Ezones to follow the features that are mapped in the adopted 2012 Natural Resource Inventory. The Ezones are applied to streams, vegetation, and wetlands. In some cases, the proposal will be to expand the Ezones on some properties. The Ezones will also contract in some locations, where there are no resources. But the intention is not to favor or disfavor development in any location, it is to apply the Ezones using a clear and objective methodology to the features that were intended to be protected when the original Ezones were adopted.

Project steps and timeline

Between June 2018 and June 2020, staff attended community meetings, held open house events, and conducted site visits with property owners. Due to COVID-19, some of the events took place online. In June 2020, a draft of the full project report was posted for public review and notice was sent to all impacted property owners.

The Planning and Sustainability Commission (PSC) held public hearings on July 28, 2020, February 23, 2021, and August 24, 2021. On September 28, 2021, the PSC voted to recommend the Ezone Map Correction Project to City Council. 

City Council held a first hearing on the Ezone Project on February 16. A second hearing is scheduled to occur on April 14 at 2:00 PM. At that hearing, City Council will be reviewing amendments, including edits to natural resource mapping that have been made since the end of PSC hearings. Proposed amendments will be posted on the Ezone Project webpage prior to the hearing. Members of the public have until April 13 at 4:00 PM to register to testify at the hearing.

View the project calendar including past events.

How Ezones affect development

If your property is already developed with a house or business, the structure, driveway, yard, parking and loading area, etc. can remain, be maintained and repaired, and in most cases, be replaced. The Ezones could impact if or where an expansion, such as a new deck or a garage, is allowed. You can print examples of what is allowed on a residential or industrial lot:

If the site is vacant, the Ezones allow a certain amount of disturbance to accommodate a new house or business. Please see the General Development Standards of zoning code 33.430.140.A-S. If a proposed development cannot meet these standards, Environmental Review is required, as described in zoning code 33.430.210.

There are many factors that impact if and how a site can be developed, including landslide hazards, floodplains, access to water and sewer infrastructure, access to public rights-of-way, etc. Please contact Ezone staff to learn more about your specific site.

What if you already have a permit to subdivide or develop in an Ezone?

Land use reviews and permits that are filed before the corrected Ezones are adopted are vested in the current zoning code and will not be impacted by the changes. There are time limits on how long land use review approvals and permits are valid – please review your approval or permit closely.

Ezones and property value

Many factors can affect property value, so it’s hard to say what will happen due to Ezone changes on your property. A study done in Portland (Netusil, 2003) found that for many parts of Portland, the Ezones have no clear impact on property sale price and in limited areas the study found the Ezones could have either a negative or positive effects on property sale price. In general, the presence of natural resources, such as trees, have a positive influence on property values (EcoNorthwest, 2009), but every situation is different.

A stream, with houses on both sides, surrounded by trees.

Under Measure 49, if a local jurisdiction adopts a regulation that restricts the residential use of private property, and that restriction reduces the fair market value of the property, then the owner may be entitled to compensation. Land use regulations that restrict or prohibit activities for the protection of public health and safety are exempt from Measure 49. The Ezones are applied in part to protect high risk areas such as streams, flood areas, and steep slopes from additional development impacts that could increase risk to public health and safety from natural hazards including erosion, landslides, and flooding.

It is up to a court to determine whether a property owner has an eligible Measure 49 claim. If you have questions about the applicability of Measure 49 to your property, please consult your attorney.

Ezones and property taxes

There are a number of circumstances that affect property taxes. For example, property taxes can change when the use of property changes, when improvements are made, or when property is sold.You can read more about assessment and taxation at the Multnomah County Assessment and Taxation website or contact the Multnomah County Taxation and Assessment Customer Service line at 503-988-3326.