Portland, OR is at the forefront of integrating green stormwater infrastructure in the United States. One secret to their success is by consistently monitoring the effectiveness of its green stormwater management technologies. This allows the city departments to further refine technologies and give the city employees confidence to promote the use of stormwater designs in city projects.
The city agency responsible for implementing green stormwater infrastructure, The Bureau of Environmental Services (BES), states, “gathering performance data on sustainable stormwater facilities is critical to quantifying benefits, improving design and function, and lowering maintenance costs” on their Sustainable Stormwater Management Monitoring website. BES publishes comprehensive monitoring reports approximately every two years since 2006 using a variety of types of monitoring:
- Infiltration testing;
- Flow metering;
- Flow testing;
- Water quality sampling;
- Sediment / Soil sampling.
In addition to water infiltration, flow, and quality measures, soil sampling was done to see if there were any long-term issues with pollutant accumulation. These measures are used to evaluate ecoroofs (green roofs), green streets, curb extensions, stormwater planters, vegetated infiltration basins, private infiltration facilities, and flow-through facilities. A number of facilities in the city are evaluated, and the list keeps growing as more stormwater best management practices are installed.
Evaluation of installed stormwater facilities also helps determine how practice compares to prediction of social, environmental, and economic benefits. In 2010, Portland published Portland’s Green Infrastructure: Quantifying the Health, Energy, and Community Livability Benefits. This report evaluated a number of green stormwater infrastructure types and summarized potential health, energy and greenhouse gas, and community livability benefits compared to a “grey,” traditional system within the Portland context.