Compared to canvas grocery bags or CFL light bulbs or even solar panels, larger "green infrastructure" projects such as roof gardens or permeable streets can be hugely expensive. It turns out, however, that they're actually not that expensive when compared to the costs of building more traditional infrastructure, and can even save money. According to a new study, governments are wasting billions of dollars a year by not going green.
Looking at 479 case studies of green infrastructure projects around the U.S., the report finds that the majority of projects turned out to be just as affordable or even more so than traditional "grey" infrastructure. About a quarter of projects raised costs, 31 percent, kept costs the same and more than 44 percent actually brought costs down.
"The lesson learned so far by early adopter communities who have already implemented green infrastructure in a significant fashion is that a wide-ranging commitment to including green infrastructure stormwater approaches, on public as well as private properties, can result in long-term fiscal savings for local governments as well as provide numerous, tangible economic and community benefits through related ecosystem services," notes the study, co-authored by the American Society of Landscape Architects, American Rivers, the Water Environment Federation, and ECONorthwest.
The costs of traditional infrastructure are especially pronounced in cities and regions with combined sewer systems that collect both sewage and stormwater. During heavy rainfall, these systems are often overwhelmed, pouring sewage-laden water into drinking water sources and greatly increasing water treatment costs.
Technologies like permeable pavements and rain gardens can capture, naturally treat and filter stormwater back into the ground, preventing overflows and reducing reliance on treatment centers. Chicago's existing green infrastructure, including its green alleys, diverted about 70 million gallons of stormwater from treatment facilities in 2009, according to the report.
These projects can create significant costs savings. New York City plans to build green infrastructure to cut down discharges into its combined sewer system – a project expected to save about $1.5 billion in treatment and infrastructure costs over 20 years. Replacing streets in Seattle with permeable pavement and other green infrastructure has cut paving costs nearly in half.
And by allowing natural processes to take over the work we've been building infrastructure to handle, operations and maintenance costs also fall. The report concedes that some maintenance on green infrastructure will still be required, but that it is significantly less than what's required by traditional infrastructure.
The report notes that water and waste water systems are responsible for a significant amount of energy use, representing about 3 percent of U.S. energy consumption annually. Green roofs can also reduce energy use by keeping buildings cooler in summer and cutting down the need for air conditioning, reducing indoor energy consumption by nearly 10 percent annually.
And though the upfront costs of projects like these can be high, this report shows that taking even a slightly long-term view of their benefits can greatly reduce government infrastructure costs overall.
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