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.
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 National Resources Inventory (NRI) and adopted by City Council in 2012.
This 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. In July 2018, staff started working with property owners to verify the NRI data. The work will continue watershed by watershed. To see a draft of updated environmental overlay zones view the Ezone map.
From the start, there will be a lot of public engagement. Staff will send postcards to impacted property owners, attend community meetings and set up site visits to learn about the streams, wetlands, forests and other unique features in neighborhoods. Please see the calendar for event listings.
This site research will be compiled to update the NRI and environmental overlay zones. Some properties may have environmental overlay zones removed because there aren’t significant resources; other properties may have environmental overlay zones applied because there are streams, wetlands, flood areas, wildlife habitat or steep slopes that need protection.
All the work will go before Planning and Sustainability Commission and then City Council for adoption in 2020.