Triple-Bottom-Line Analysis of Green Infrastructure Investments in Philadelphia
Green infrastructure includes a wide array of practices that use vegetation, soils, and natural processes to manage wet weather flows by infiltrating, evapotranspiring, harvesting, and reusing stormwater. Examples of green infrastructure include bioretention planters in sidewalks and parking lots, green roofs, tree plantings, and rain gardens. Green infrastructure investments can provide a wide range of benefits beyond reducing stormwater pollution.
The Philadelphia Water Department established its Green City, Clean Waters plan in 2009. The plan is designed to enable the city to reduce stormwater pollution entering its combined sewer system through a combination of both green and gray infrastructure solutions.
The Philadelphia Water Department commissioned a triple bottom-line analysis that considered the economic, environmental, and social benefits of a suite of green infrastructure measures. This is helping the city fully understand the benefits that could be achieved through investments under the Green City, Clean Water plan.
Abt Associates staff conducted the analysis for the Philadelphia Water Department’s primary engineering support contractor. Abt staff considered the benefits and costs of 24 proposed combined sewer overflow reduction alternatives that included different levels of green and gray infrastructure implementation. The team identified a range of ancillary benefits in addition to reduced stormwater pollution, including reduced greenhouse gas emissions, improved recreational opportunities, reduced heat-related fatalities, health-related benefits, increased property values, energy savings, and the addition of “green collar” jobs to the city’s economy.
The city used the assessment to demonstrate the merits of green infrastructure to EPA and other regulatory agencies.
Read the final report for the Philadelphia infrastructure assessment.