Atlantic Cities: Green Infrastructure Could Save Cities Billions
... 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.