What’s Really Going on in Portland? A County-Level Study of the UGB’s Effects on Sprawl in Metropolitan Portland, Oregon

Abstract

The Urban Growth Boundary (UGB) is a green belt urban policy in Portland, Oregon that artificially limits the supply of land for high-density urbanization. Although a number of cities have implemented similar growth boundaries, Portland was the first city to do so and has been lauded as the paragon for smart growth in America. Previous research has measured the effects of the UGB on controlling urban sprawl by comparing inside to outside the boundary. Although Portland, Oregon is a medium-sized city, the greater Metropolitan Portland area includes 24 cities and three counties. By knowing where the growth is taking place, we can also know which cities Oregon Metro, the governing body that determines the boundary, can successfully bet on for expansion and the UGB’s long-term success. The three counties in the UGB are Clackamas County, Multnomah County, and Washington County. Chapter III walks the reader through the history of the UGB from its early legislation in the 1970’s all the way to new changes in UGB policy that will be made at the end of 2018. Chapter IV includes a number of linear regressions that measure sprawl in the three counties in the years 2000 and 2010. The dependent variables used to measure sprawl in this thesis are housing stock and population density. My findings show that the UGB was not effective in containing sprawl in Washington County in 2000. However, according to data from the 2010 Census, the Urban Growth Boundary was able to control sprawl in Washington County, meaning that from 2000 to 2010, housing and population growth increased inside the boundary enough for the UGB to contain growth for more high-density development. According to the first-difference (FD) estimator, which removes the unobserved heterogeneity, the UGB was not effective in Clackamas County when using housing stock nor were the coefficients positive for Multnomah and Washington Counties. In other words, these results show that housing stock is not an appropriate measure for sprawl. Finally, it was found to be the case that the Urban Growth Boundary is, indeed, effective in controlling sprawl in Clackamas and Multnomah Counties according to the population density FD model, but UGB was found to not be effective in Washington County. Because the regression and FD population density models for Washington County do not agree about the UGB’s ability to contain sprawl, efficacy in Washington County is still up for debate and further research in the field should address this inconsistency.