The Dream

Having a natural resource on your property is a luxury most people don’t get to enjoy. In the landscaping industry, the most common situation we see is a new home owner who has inherited a running stream in their backyard. The client usually wants to make the most of this unique resource: Build a fire pit patio nearby to create the perfect camping atmosphere. Add a bridge to get to the other side. Carve out a small wading pool. Enhance it with boulders and river rock…


The Reality

Unfortunately, what can legally be done is a lot more sobering. In the Portland metro area, there are strict guidelines to what development is and isn’t acceptable. The stream running through your property can be affected by others upstream, just as you can affect it downstream. The City has a public responsibility to protect our natural resources. Any development can trigger an environmental review and require a fairly involved permitting process. It’s necessary to contact your local water management agency and alert them before any development takes place, preferably in the design phase.


The Answer

Without getting too technical, there is a general guideline that gives an idea of what the restricted area of a stream will be. If it runs year-round (perennial), assume there’s a 50’ sensitive area on each side. If the stream is intermittent (dry during the summer), the buffer may be from 15-25’ on each side. Note, these are just rough estimates. Other factors include how steep the terrain is and if the stream is tied to a wetland.

The City of Portland provides a handy map with environmental overlay zones so you can find out if there are any regulations at your address. This map is available at There are 2 important zones: conservation zone and protection zone. The c-zone is applied to natural resources that are important but where some environmentally sensitive development may be permitted. The p-zone is applied where the resources are critical and development should be avoided except under special circumstances. In either c- or p-zones, the location and extent of development needs to minimize impacts on the resources, and the property owner is responsible for the replacement of any resources that are lost. On the upside, it should be noted, for a new home owner with property that falls within this area, the agency tends to be more flexible in what level of development is allowed.


Hire a Consultant

Probably the easiest way to find out what you can and can’t do is to hire an environmental consultant. This person will be familiar with the regulations and will be capable of navigating through all the paperwork and the permitting process in a timely fashion. Attaining the dream isn’t impossible, it just might change along the way.


Relevant Portland, Oregon links:

City of Portland Environmental Overlay Zones:
Environmental Overlay Zones Map:
Clean Water Services (for outside the Portland area):