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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Room 1000, Portland, OR 97204

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Table of Contents
Land Use and Population
The descriptions below provide general information for each topic. Click on each topic to get subwatershed specific descriptions.

BES Revegetation Projects
Through the Watershed Revegetation Program, Environmental Services forms partnerships with public and private landowners to restore degraded stream banks, wetlands, and upland areas. This restoration work improves water quality by controlling erosion, reducing stormwater pollution, aiding in long-term salmon recovery, and enhancing wildlife habitat.

Current Zoning
Current base zoning does not necessarily represent existing land uses but rather the desired land use pattern set out in the goals and policies of Portland’s Comprehensive Plan and implemented through the Zoning Code. Descriptions of current base zoning are provided for each subwatershed. A table summarizes total acres for each zone.

The Oregon Department of Environmental Quality (DEQ) maintains an Environmental Cleanup Site Information (ECSI) database to track sites with known or suspected hazardous substance contamination. According to the DEQ, the data in the ECSI is “working information,” and the agency further specifies that information in ECSI may be unconfirmed, outdated or incomplete; is summary in nature, rather than comprehensive; there may be contaminated sites in Oregon that are unknown to DEQ and do not appear in ECSI and conversely, the appearance of a site in ECSI does not necessarily mean that the site is contaminated; and information in ECSI is subject to change at any time. The site information provided for each subwatershed is from the ECSI database as of summer, 2003. It has not been reviewed, and only in a few cases has the information been summarized. For complete and recent site information, visit the DEQ's ECSI website

Development Patterns
Humans have lived in the Portland area for more than 10,000 years. The native inhabitants used fire to manage the landscape for food production, and the oak savanna covering of the Willamette Valley was the result of a long history of human influence. After the Hudson’s Bay Company established a fur trading post in Astoria, trapping parties dramatically reduced the beaver population across the region in an effort to thwart competition. The extent of the impact on riparian zones is not documented, but can be assumed to be significant. Similarly, the introduction of horses to the area in the 1700s led to an increase in deliberately set fires to provide additional grasslands for grazing.

But the arrival of significant numbers of settlers in the 1840s marked an acceleration in the rate of change for the watershed. Agricultural ‘improvements’ drained riparian wetlands, and logging stripped the forest cover. Road and rail transportation systems concentrated polluted runoff and allowed more widespread resource extraction. The growth of towns added municipal sewage and industrial wastes to the river.

Portland was founded in 1843 and by 1850 had a population of about 800, a sawmill, hotel, and newspaper. In 1891 an election consolidated Portland with Albina and East Portland, towns on the east bank of the Willamette River. By the early 1900s, much of the floodplain and riparian area along the river had been filled for urban development.

Portland’s location at the confluence of two major river systems played an important role in its development. William G. Robbins described the efforts to ‘improve’ the region’s waterways in his book, Landscapes of Promise:

“For the Pacific Northwest, few aspects of human cultural activity were more visibly obvious than the myriad efforts to divert and control the region’s extensive waterways. Although the region’s major streams – the Columbia, Snake, and Willamette – were the focal point of much of the attention, developers, commercial shippers, engineers, and a broad array of agricultural groups expressed interest in virtually every stream and waterway. Collectively that industrial modeling of Northwestern rivers including the dredging and channeling of streams, building jetties, and erecting dams to improve navigation, control flooding, provide water for irrigation, and generate electricity.”

On the Willamette, the work began in the 1860s with snag-pulling operations to improve navigation for river transportation of wheat. Diking, bank hardening, and dredging increased in the Portland Harbor as grain and lumber shipping became important economic activities. Floodplain and wetland areas, including Guilds Lake in northwest Portland, were filled to make room for development. A causeway connecting Swan Island to the east bank redirected the river’s channel, and the increased flow helped eliminate a troublesome rapid that impeded navigation.

By the late 1800s the Willamette’s seasonal flooding had become a serious issue for the growing towns along the river. Several, including Portland, built revetments and other bank treatments to contain the flood waters. In the 1930s industrial, commercial, and agricultural interests had joined forces with local political leaders and the Army Corps of Engineers to promote the Willamette Plan. The plan called for a system of dams on the Willamette and its major tributaries for flood control, irrigation, and power. Over the next 40 years dam construction changed the natural flow regime of the basin, eliminating both the flood waters of the winter and spring and the low flows of the summer and fall.

Portland continued to grow, annexing large areas of unincorporated Multnomah County generally east of SE 82nd Avenue in the 1980s. Some of the former industrial areas along the river have been redeveloped for commercial and residential uses. Most of the urban area is already developed, but infill construction and an increase in apartment and condominum construction have increased density, a trend that is expected to continue.

Site-specific development patterns are described for each subwatershed.

Employment data are based on Metro’s estimates of retail, non-retail and total employment by Transportation Analysis Zone (TAZ).

Future Zoning
Descriptions of comprehensive plan zoning designations, and how they correspond to current zoning, are provided for each subwatershed. A table summarizes total acres for each zone. For brief descriptions of current and comprehensive plan zones and a link to the City of Portland’s zoning code, (click here).

Impervious Area
Estimates of total impervious area are provided for each subwatershed. A table summarizes impervious area, divided into three categories: buildings, streets, and parking lots. These figures are estimates and may contain inaccuracies. For example, the estimates of street acreage may include both pervious and impervious (dirt) streets and public rights of way where streets have not been built.

Metro Goal 5 Habitat Inventories
Metro has developed an inventory of regionally significant riparian and wildlife habitat resources as the initial step in developing a regional program to comply with State Land Use Planning Goal 5.

Open Space
A brief description and summary table of open space is provided for each subwatershed. Both public and private open space is included.

Overlay Zones

Plan Districts
Plan districts address concerns unique to an area when other zoning mechanisms cannot achieve the desired results. An area may be unique based on natural, economic or historic attributes; be subject to problems from rapid or severe transitions of land use; or contain public facilities which require specific land use regulations for their efficient operation. Plan districts provide a means to modify zoning regulations for specific areas defined in special plans or studies. Each plan district has its own nontransferable set of regulations. This contrasts with base zone and overlay zone provisions which are intended to be applicable in large areas or in more than one area(City of Portland Bureau of Planning, Title 33, Chapter 33.500).

Population for each subwatershed has been estimated using 2000 US Census data at the tract level.

Public Land
A brief description and summary table of public land is provided for each subwatershed.

Urban Renewal Areas
The Portland Development Commission (PDC) has designated urban renewal areas throughout the city. Specific plans in each area guide development.

Vacant Land
Vacant land, identified by Metro in 1999 using aerial photography, is defined as tax lots that have no buildings, improvements or identifiable land use. Additionally, if a developed tax lot has ½ acre or greater portion that is vacant, the vacant portion is considered vacant land. Parks and open spaces are not considered vacant land.

Maps & Files

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