Detroit Cancels Costly Combined Sewer Overflow Tunnel

A report in the "Detroit Free Press" Saturday quoted George Ellenwood, a spokesman for the Detroit Water and Sewerage Department, as saying sewer fees would have been 16 percent higher as of July 1 if the long-planned tunnel had gone ahead.

In view of the Motor City's current 22 percent unemployment rate, "It exceeds what is considered reasonable," said Ellenwood,

Detroit, like many Midwestern cities, has a combined sewer system that carries both sanitary sewage and stormwater. During heavy rain and snow melt, the flow capacity of a sewer system is exceeded and an overflow of this mixture runs into the Rouge River.

Detroit in the pouring rain (Photo by Djuroslav)

The seven mile long Upper Rouge CSO Tunnel was designed to capture up to 201 million gallons of wet weather flows conveyed through existing sewer infrastructure located in western Detroit from 17 designated outfalls that historically discharge to the upper tributary of the Rouge River.

It would also have captured overflows from three outfalls in Dearborn Heights and eight outfalls in Redford Township.

The tunnel would have stored the combined sewage and stormwater until it could be treated at the Detroit Wastewater Treatment Plant and discharged.

Construction of the tunnel is a requirement of the Detroit Water and Sewerage Department's 2008 NPDES Permit, and is a condition of a consent decree in litigation brought by the U.S. Environmental Protection Agency. It was supposed to be completed in the 2014-2015 timeframe.

Ellenwood said the department will seek an alternative during the next six months.

Plans for the tunnel have been stalled for months for lack of financing.

In late February, the Detroit Water and Sewerage Department canceled plans to bid the North Tunnel section, advising prospective bidders not to submit any bids. No official explanation for the cancelation was offered.

Still, continued work was planned for the South Tunnel. A contract for this section of the project was awarded to Kenny Construction and Japan's Obayashi Corporation in September 2008.

Friday's decision canceled work on both North and South tunnel sections.

The tunnel was designed to be 30 feet in diameter. It would have run parallel the Rouge River, mostly under park space, 160 feet below ground from Pembroke Avenue and Berg to Warren Avenue and West Outer Drive. The tunnel was intended to cut the frequency of overflow events from about 50 a year to fewer than one a year, reducing the overflow from an average of 1.3 billion gallons to 250 million gallons annually.

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