Another issue is that the Deep Tunnel will not prevent all untreated sewage releases into the river and Lake Michigan, since overflows often happen because of bottlenecks in the network of smaller pipes that lead to the Deep Tunnel.
“You can have infinite storage capacity, but unless you can move enough water quickly enough to the storage area, you’re still going to have problems,” said Joel Brammeier, president of the Alliance for the Great Lakes.
The E.P.A. and planning and environmental groups say cities should reduce the amount of rainwater flowing into sewer pipes through a range of so-called green infrastructure projects, including permeable pavement that lets water trickle through; sunken medians lined with gravel or plants; green roofs and retention ponds.
The draft consent decree requires the water reclamation district to spend $325,000 on green infrastructure, which critics say is far too little. The federal government has ordered other cities to spend millions on green drainage methods — $42 million in Cleveland alone.
Federal officials and Ms. Young said they could not comment on the consent decree because of ongoing negotiations.
Ann Alexander, a senior attorney for the Natural Resources Defense Council, said the district is too fixed on traditional solutions. “They don’t believe green infrastructure can really solve problems, they think of it as something dreamed up by hippies,” she said.
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