Portland’s "smart growth" pays off, Clark County comparison shows

Land-use analysis quantifies striking differences in two states’
approach to growth

Portland – If Portland’s Metro region had grown like Clark County in the
1990s, development would have overtaken an additional 14 square
miles of farmland and open space. That’s one finding of an analysis
released today by Seattle-based research center Northwest
Environment Watch (NEW). Titled "Sprawl and Smart Growth in
Metropolitan Portland," it finds that while greater Portland’s three
Oregon counties "grew smarter," and encouarged more compact,
efficient communities, neighboring Clark County sprawled–and lost
more rural land and open space per new resident, as a result.

"Few areas in North America provide such a stark illustration of
different approaches to planning," says NEW research director Clark
Williams-Derry, who will be presenting the research to Portland’s
Metro Council today at 2pm. "And with a measure on Oregon’s May 21
primary ballot designed to weaken Portland’s growth
management-making it more like Clark County’s-the comparison is
especially interesting."

The study used satellite imagery of open space, farmland, and
pavement, plus digital mapping of US Census data to track patterns of
growth during the 1990s, in Multnomah, Washington, and Clackamas
Counties, Oregon, and in Clark County, Washington. Key findings
include:

In the 1990s, greater Portland’s total population grew at a
faster pace than many developing-world megacities, such
as Cairo, Egypt, and Jakarta, Indonesia.

In the Oregon counties, total population increased by
270,000, and the number of people living in compact,
transit-oriented neighborhoods (defined as 12 or more
people per acre) increased by 141,000. By 2000, 28
percent of residents in the three-county region lived in
compact neighborhoods.

In contrast, Clark County sprawled, Seattle-style. The
population grew by 106,000, and the number of residents of
low-density, car-dependent areas (defined as less than 12
people per acre) increased by 78,000. By 2000, only 13
percent of Clark County’s residents lived in compact
communities.

Per capita, Clark County converted about 40 percent more
land from rural to suburban population densities than did the
Oregon counties. If the Oregon counties had grown in a
pattern similar to that of Clark County, suburban
development would have overtaken an extra 14 square miles
of farmland and open space.

Person for person, Clark County’s sprawling residential
development fully or partially covers 23 percent more land with
pavement, rooftops, and other human-made "impervious"
surfaces-which are harmful to streams and salmon-than
Oregon’s more compact residential neighborhoods.

NEW’s analysis also looked at the relationship between traffic
congestion and density, and found that although population growth
increases traffic congestion, neighborhood density has less effect
than total metropolitan population. "In fact," says Williams-Derry,
"compact urban designs may slightly decrease the number of hours
we lose to traffic jams."

http://www.northwestwatch.org/press/portland_sprawl.html