58
PNW Ecosystem Research Consortium
S
N
te
Diverging from this general pattern are areas such as the city’s core,
where citizens work but do not reside. Additionally, parks and open space in
Portland were designed to be close to the urban center. Consequently,
densities in the highest ranges are adjacent to densities in the lowest range.
This contrast of densities is also visible along the city’s northern edge, where
industrial zones near the Columbia Slough adjoin residential zones.
et
city’s main core. In general, with greater distance from the core, the density
decreases. This pattern is also visible in the towns of Beaverton, Newberg,
Hillsboro, and Canby.
W
Smith Lake
Bybee L.
m
illa
ve
Ri
Density is concentrated east and north of the Willamette River, near the
Currently, areas within city limits occupy 4% of the Willamette River
Basin’s area. Urban growth boundaries indicate that the percentage of land
covered by cities can rise to 6%. Expanding urban areas imply a change in
the economic base and also presume increasing future population densities
in places that are presently not considered urban. These changing densities
can be seen on the facing page map of Portland and the growing cities
surrounding it (Map 12).
of 1,000 or more people per square mile in shades of brown and those areas
with densities of less than 1,000 people per square mile in shades of green.
Places of urban and non-urban settlements are distinguished by using
opposing colors to represent these density ranges. The graduated color
scheme employed within this opposing color framework is based on the
continuous density spectrum that spans urban and non-urban areas. This
representation emphasizes density thresholds between urban and non-urban
areas as defined by the U.S. Geological Survey as well.
As defined by the U.S. Bureau of the Census, an urbanized area
comprises one or more places with a minimum of 50,000 persons and at
least 1,000 persons per square mile. This map depicts areas having densities
r
lum
b
ia R
Ross
Is.
iver
Figure 78. Detail of 1990 population density in the Portland metropolitan area.
Co
S
N
Outside Portland UGB
Roads
River
Lake
City Limits
Urban Growth Boundary
0
1-39
40-120
121-344
345-999
1000-1703
1704-2538
2539-3337
3338-4006
4007-4665
4666-5267
5268-5893
5894-6480
6481-7089
7090-7748
7749-8510
8511-9420
9421-10769
10773-13463
13466-919809
Population Density
Persons Per Mi 2
Not to Scale
Enlarged
Areas
72
1990 Portland Area Population Density by Census Block
1990 Population Density
H. Dearborn J. Goicochea Duclos
S
N
Willamette River Basin Atlas
2nd Edition
McMinnville
Dayton
Saint Paul
Hubbard
Donald
Wilsonville
Newberg
R
Co
lu
mb
ia R
Aurora
Tualatin
Lake Oswego
Tigard
l la
Wi
Lafayette
Dundee
Beaverton
m
et
te
Sherwood
Hillsboro
North Plains
r
ive
Carlton
Yamhill
Gaston
Forest Grove
Banks
Scappoose
72
Gresham
Fairview
Troutdale
Oregon City
Portland
Mollala
Canby
iver
5km
5mi
10km
15km
10mi
Estacada
Sandy
Note: This map uses the same legend as the facing page
0km
0mi
Scale 1:300000
Projection UTM Zone 10
Map 12. 1990 Population Density in the Northern Willamette Valley
HUMAN POPULATION
Map 12.
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