DETROIT: The bankrupt city, already roiled by financial and political turmoil, is struggling to upgrade its antiquated combined stormwater/sewer system as storm intensity has increased over the past few decades. Image: Flickr/Dave Linabury
DETROIT – The spring rains came bursting down this year, and down again and yet again. And in this bankrupt city, the aging sewage system couldn't keep up – just like it couldn't in 2011 and 2009.
So on a Thursday morning in April, Detroit's wastewater managers opened 11 pipes and sent 110 million gallons of raw sewage spewing into the Detroit River. They poured another 3.5 million into the nearby Rouge River.
There was a brief letup. Then six days later came the clouds and the rain. And another 75 million gallons of sewage tumbled into the Detroit River.
"That week, April 11 to about the 18th, we were running at about 1.5 billion gallons a day" at the wastewater treatment plant, said Dan Schechter, superintendent of engineering at the Detroit Water and Sewerage Department, at his desk at the Detroit Wastewater Treatment Plant on the city's industrial southwest side.
The plant can only treat 930 million gallons a day. Concrete basins designed for overflow can only hold so much – so the rivers receive the rest. Heavy flows get diverted to retention basins until the system can catch up. But when basins fill, the pipes to the rivers open.
For Detroit, bankrupt and dealing with political and financial turmoil, this is a crisis: An aging, flood-prone sewer system sends raw sewage into the Detroit River during intense downpours. Such spewing can expose people who swim or paddle the river to disease-causing bacteria and viruses. The Detroit River also links the upper and lower Great Lakes, so its contamination affects the health of the region's entire watershed.
There's little question the region is already dealing with the impacts of a changing climate. Rain from heavy, flood-causing storms has jumped 45 percent across the Midwest the past five decades, according to federal scientists. Greenhouse gases increase the energy in the atmosphere and tend to concentrate storms. Southeast Michigan, thanks to a quirk of atmospheric currents and geography, has been hard hit: Annual precipitation has increased 10 to 15 percent in and around Detroit the past 30 years.
In a city where services are beyond strained, climate change is compounding the woe.
"Without trying to sensationalize – it's like a slow (Hurricane) Katrina here," said Larissa Larsen, an associate professor at the University of Michigan and co author of a report on climate change vulnerability in Detroit by the Detroit Climate Action Collaborative. "Whether it's climate caused flooding, a serious blackout or extreme heat, I'm scared … especially for those vulnerable populations."
A combined sewer system means sewage and stormwater go to the same pipes. These systems are no longer built because when it rains hard it can lead to bacteria-tainted water overflowing. Still, about 800 U.S. communities – mostly in the Pacific Northwest, the Northeast and the Great Lakes region – are served by combined sewer systems, according to the EPA.
Detroit's is one of the oldest.
Rains keep coming
Overhauling a combined sewer system costs billions. Detroit, saddled with a $330 million spending gap this year and almost $16 billion in long-term debt, is ill-prepared to undertake such an endeavor. The state appointed an emergency manager to take control of city finances in March, and the city declared bankruptcy on July 18.
Yet the rains keep coming. In the wettest year on record, 2011, Detroit spewed about 7 billion gallons of untreated sewage into the Rouge and Detroit rivers, according to the Michigan Department of Environmental Quality. An additional 25 billion gallons of partially treated sewage – where solids were removed but the water wasn't disinfected – poured into the rivers that year as well.