Valuing Green Infrastructure in Portland, Oregon

By Noelwah R. Netusil, Zachary Levin, Vivek Shandas, and Ted Hart

Portland, OR (February 2014) – This study uses the hedonic price method to examine if proximity, abundance, and characteristics of green street facilities affect the sale price of single-family residential properties in Portland, Oregon.

Portland green infrastructureGreen Street facilities in Portland to manage stormwater are described as follows:

  • A green street facility is a small rain garden that collects stormwater runoff from streets.
  • Green street facilities keep stormwater out of the sewer system and local streams.
  • Green street facilities are important parts of the city’s green infrastructure and help protect and improve the efficiency of the city’s grey, or pipe, infrastructure.
  • Green street facilities help prevent sewer back-ups in basements and combined sewer overflows (CSOs) to the Willamette River.
  • Green street facilities increase urban green space, improve air quality, replenish groundwater, and reduce air temperature.

Learn more about Portland Green Street Facilities.

Different methods for measuring proximity and abundance are explored in the research with distance based on street network, and abundance of green streets at the census tract and census block level, producing statistically significant results.

Findings suggest a property’s sale price is estimated to increase as distance from the nearest green street facility increases although the magnitude of this effect is small. Facility type does not have a statistically significant effect on a property’s sale price, but characteristics such as facility size, proportion of the facility covered by tree canopy, and design complexity are estimated to influence sale price.

This research is important in light of recent news articles on resident and business concerns about green infrastructure, both costs and function. In addition, a lawsuit by large industrial customers has branded the city’s Gray to Green and other green infrastructure programs as “unauthorized expenditure” and demanded a full accounting of where the money is being spent. This article explores the citywide debate: Are bioswales and related Green Streets projects a good investment for the city’s utility ratepayers? Or are they a nonessential frill pushed by green do-gooders? Read the full article: “Green Streets: Function or Frill?

Source: “Valuing Green Infrastructure in Portland, OregonLandscape & Urban Planning