The U.S. could save tens of millions in avoided flood losses from 2020 to 2040 if it were to increase the use of green infrastructure in new developments, according to Flood Loss Avoidance Benefits of Green Infrastructure for Stormwater management, a report prepared by Atkins and published by the U.S. EPA.
Low Impact Development (LID), green roofs, permeable pavement, rainwater harvesting and other green infrastructure BMPs could also be employed on existing sites and buildings, further reducing losses due to flooding.
The report is the first in the U.S. to quantify the impact of GI on the damage caused by flooding.
“The report helps start a holistic conversation about rainwater and floodwater management that links water-quality improvements and the flood losses that can be avoided by implementing green infrastructure,” said Dan Medina, Atkins’ technical director and author. “GI’s benefits to water quality, groundwater recharge and stream channel protection are well known, but its impact on the magnitude of floods at the catchment level have not been investigated until now.”
Atkins modeled 20 watersheds in areas where significant growth is expected between 2020 and 2040 and compared the monetary value of flood losses with and without GI.
The study found the annual savings to the U.S. in 2040 would range from $63 to $136 million if GI was more widely adopted on new development and redevelopment. If the benefits started at zero in 2020, the value of the benefits in the following 20 years was found to range from $0.4 and $1 billion. The estimates only include buildings, their contents and associated income loss. The study did not include roads, bridges, utilities and other critical infrastructure.