Abstract:
Communities across Oregon have begun to take an interest in non-traditional approaches to stormwater
management. Of these approaches, those designated as “Green Infrastructure” have begun taking a
major role. Green Infrastructure is a blanket term to denote natural or semi-natural systems which
perform a valuable service for human communities. Stormwater Green Infrastructure aims to capture,
store, infiltrate, or slow down precipitation and runoff at the site level. Green Infrastructure has a
number of benefits, including lower capital and operational costs versus traditional systems, flexibility
in terms of scale, carbon sequestration dividends, and resilience to natural hazard events.
Of particular note, constructed wetlands or extended wet ponds are a Green Infrastructure strategy
successful in treating large volumes of stormwater and providing natural habitat for wildlife
communities. According to the Environmental Protection Agency, these projects are defined as
“treatment systems that use natural processes involving wetland vegetation, soils, and their associated
microbial assemblages to improve water quality.”
Many successful examples of constructed wetlands lie within small and mid-sized communities in places
such as Arcata, California, Houghton Lake, Michigan, and Cannon Beach, Oregon. However, despite
their realization in many places, constructed wetlands have yet to see widespread application across
Oregon. Along with institutional resistance to change and maintenance concerns, a primary reason for
this lack of investment is missing information on areas suitable for constructed wetland projects. Smaller
communities in particular often lack the time, formal knowledge, and appropriate tools to perform a
rigorous assessment of which locations in their community may be suitable.
To address this shortfall, this report presents an automated Geographic Information System (GIS)
suitability analysis tool for constructed wetland projects in Oregon. Rather than serving as a detailed
“site selection” tool, this program is intended as a “site search” tool to identify the boundaries of
suitable project areas and associated characteristics. The analysis itself is performed using a range of
geographic data sets related to a variety of accepted constructed wetland practices and design
techniques. To maintain the largest possible assortment of potential users, all datasets and the tool
programming language within this program were gathered from open source locations such as the State
of Oregon’s Spatial Data Library. To illustrate the applicability of this tool, a sample suitability analysis
was performed in Cottage Grove, Oregon. This analysis was evaluated along with relevant local planning
documents and case studies of successful constructed wetlands projects in various land use situations.
These results have been presented to give greater direction in how this analysis tool might be utilized
and applied by other Oregon communities.