100s Of Billions In Sewer Improvements Already Out Of Date, Thx To Use Of Decades-Old Rain Data
EDIT
Spilling large amounts of sewage into waterways is a direct violation of the Clean Water Act. And many cities, from Detroit to Chicago, have been forced to sign consent decrees with the EPA, requiring them to reduce the number of overflows by upgrading water infrastructure and capacity. This process, however, can take decades from planning, funding, and permitting to completion, said Becky Hammer, an attorney with the Natural Resources Defense Council who focuses on federal clean water policy. That means the rainfall estimates that dozens of cities use to design their billion-dollar projects are already obsolete by the time they’re finished. The government’s own rainfall estimates are also outdated — it last released figures for Ohio, for example, in 2004 — making planning difficult even if updates were required.
Youngstown, Ohio finalized a $160 million long-term control plan for sewage overflows in 2015 based on rainfall data from the early 1980s. It’s currently in the second phase of its plan, which involves constructing a “wet-weather facility” to store and treat excess sewage and stormwater during periods of heavy rain. Indianapolis is halfway through a $2 billion tunnel project that was designed more than 20 years ago, using precipitation estimates from 1996 to 2000. Chicago is in the final stage of a nearly $4 billion effort to construct 109 miles of tunnels and three reservoirs that was designed in 1972, then updated based on modeling conducted in 2012.
Now, climate change is setting these infrastructure projects even further behind. In the decades since cities’ plans were first approved, storms in the Midwest have grown more frequent and intense. Total annual precipitation in the Great Lakes region has increased by 14 percent, according to research from scientists at the University of Michigan, and the amount of rainfall from the heaviest storms has grown by 35 percent.
EDIT
Cleveland started the overhaul of its water infrastructure system in 1994 under the federal Combined Sewer Overflow Control Policy, and work got underway after signing a consent decree with the EPA in 2010. The $3 billion initiative, known as Project Clean Lake, was designed using rainfall data from the early 1990s. The project’s seven new tunnels — three of which are complete, with another operational next year and three others in the construction and design phases — are built to capture most of the runoff from the “largest-volume storm” in a “typical year,” which would dump 2.3 inches of rain in 16 hours, said Doug Lopata, a program manager for the Northeast Ohio Regional Sewer District. Since Cleveland began planning Project Clean Lake, however, climate impacts have gotten worse. In September 2020, Cleveland received nearly four inches of rainfall in 24 hours, the third-highest total for a single day in the city. Half of the top ten rainfall days in the city have occurred since 2000, with more than 3.5 inches of rain falling in a day in 2005, 2014, and twice in 2011. Looking ahead, more intense rainfall in the 21st century “may amplify the risk of erosion, sewage overflow, interference with transportation, and flood damage” in the Great Lakes region, Michigan researchers found.
EDIT
https://grist.org/cities/cities-are-investing-billions-in-new-sewage-systems-theyre-already-obsolete/