Cascadia Expects Millions of New Residents. Should it Build New Cities or New Density?

[Updated December 1, 2020. Headline adjusted and details added to correctly report the forecasted population growth.]

Joshua McNichols reports that a new report by the Cascadia Innovation Corridor proposes four new, large cities for the region to accommodate all the growth expected in the near time future.

"Former Washington Governor Christine Gregoire, along with her peers around the region, recently published a study that argues the Northwest has a problem -- it needs four new large cities. Otherwise, there won't be enough room," writes McNichols to explain the Cascadia Vision 2050 report. The new cities would be home to "300,000 to 400,000 people, along with 200,000 jobs each, built densely around fast mass transit."

"The study’s authors don’t say exactly where these new cities should go, except they need to be at least 40 miles outside existing urban areas, in order to keep land costs down. They recommend that by 2035, the region should have found spots for them and started digging," adds McNichols.

The other option, according to the report, is for existing cities to "bulldoze" 40 percent of existing single-family homes and replace them with more density. That idea is much more palatable to Doug Trumm, writing for The Urbanist in response to the both the report and the coverage of the report by McNichols.

Trumm suggests that new zoning could help existing cities manage expected growth without needing to plan new communities from scratch. Trumm faults the report for saying new density requires bulldozing anything. "For one, converting oneplexes (detached single-family homes) to fourplexes would not necessarily require demolitions. Accessory dwelling units (ADU) offer a way to add density without teardowns. Seattle, Tacoma, Burien, Olympia, and several other cities already laws permitting and promoting ADU conversion," writes Trumm.

Not only is that language inflammatory, according to Trumm, but so is the 40 percent figure cited in the report.: "the 40% figure sounds dramatic but over 30 years that only requires about 1.2% of single family homes to be converted to fourplexes per year."