Portland-Vancouver Metropolitan Region

• Prior to 1960, Celilo Falls (shown on the left) was an historical Indian fishing location.
• The Dalles Dam was finished in 1960 (shown on the right).
• The buildings seen in the foreground (right) were moved from Celilo Falls prior to the formation of Lake Celilo behind the dam.
• photos: Aris M. Sherwood

Regional Assessment of Land Use Change

A U.S. Geological Survey team, at NASA Ames Research Center, has dedicated themselves to the development of a multi-scale, multi-resolution database and geographic analysis of spatial changes in the Portland-Vancouver metropolitan region. This temporal mapping project is just one of several projects mapping major metropolitan regions within the U.S. Temporal mapping provides a historical perspective of spatial changes over time, highlighting incremental changes. A geographic analysis helps to explain why and how development has occurred within a study area.

Development of any region includes urbanization, agricultural intensification, resource extraction, and water resources development. These human-induced phenomena have significant impact on people, the economy and resources. The growing problems of urban sprawl include loss of natural vegetation and open spaces, and a general decline in the spatial extent and connectivity of wetlands, wildlife habitat, and agricultural lands.

The study area for the Portland-Vancouver project extends the length of the Willamette Valley and from the coast to the peaks of the Cascades. The northern boundary is 46[[ring]] 30', including Longview, Washington. The western boundary is 124[[ring]] 15', including development along the Pacific coast. The eastern boundary is 121[[ring]] 30', going as far east as Hood River. The southern boundary is 43[[ring]] 45', just south of Eugene, Oregon.

Within this study region several environmental issues have surfaced in the past decade. Many of the issues center around development pressures and include threatened and endangered species, decreases in fisheries and forestry yields, declines in biodiversity and water quality, and limits on water availability. At the center of the study area is the Willamette River basin. This basin covers 11,500 square miles. Within the basin are more than 5,000 miles of rivers and streams. Recently, the Willamette River was been designated as American Heritage River. This designation, combined with Ecosystem Management Plans being established for the region, have placed greater emphasis on understanding the role of human-induced changes to the landscape.

One of the goals of this project in the Portland-Vancouver metropolitan region is to illustrate the rate at which these human-induced changes are occurring. The regional database will provide a strong visual portrayal of recognized growth patterns, and dramatically convey how the progress of modern urbanization results in profound changes to the landscape. It will also accurately reference changing geographical features so that researchers can use the database as a tool in meaningful scientific inquiry and modelers and use it as a source of information to model and predict future patterns of change. A computer animation will be used to illustrate the database and emphasize the impact of incremental urban growth.

The integration of a variety of data sources is the key to the development of this database. Integration of existing historic maps with remotely sensed data and related geographic information will allow the team to dynamically map urban land characteristics for such a large metropolitan area.

The final geo-referenced temporal database will contain data layers representing urban extent , principal transportation routes, hydrography, and population. The transportation data layer will demonstrate the influence that the transportation infrastructure (roads, railroads, and seaports) have exerted on population development. The hydrography data layer will contribute to the historical understanding by depicting changes to water resources over time as reservoirs for water supplies are built, and river channels are redirected.

The schedule for this project is based on three years of funding, 1997-1999. The database of urban and transportation will be completed during the first year and a half. During the second year of this project the hydrography data layer will be compiled, the geographic analysis of change will be started, an Open File Report for USGS will be written, describing the methods and results of this project, and an evaluation of future urban growth will be made using the predictive model. Also, during year two, we will be seeking collaborators for specific temporal analyses of either other land cover types, such as agriculture, river systems, and forest land, or high resolution looks at individual cities, to be completed during year three.

Development History

Population History

Definitions, Classification Scheme, Collection Criteria

Source Materials

References

Metadata Documentation

Slide Presentation from GIS in Action Conference, April 1998

Regional Contacts