After all these years, the Northeast Ohio Regional Sewer District reached yet another milestone in July when its third of seven large-scale combined sewer projects, the Doan Valley Storage Tunnel (DVT), went online.
The nearly two-mile-long and 18-foot-wide tunnel broke ground in 2017 and began receiving flow this month to keep pollution and our Great Lake going separate ways: the tunnel stores combined stormwater and sewage for treatment and reduces combined sewer overflows by 230 million gallons a year along Doan Brook from Shaker Heights all the way to Lake Erie.
DVT, originally a $142.3 million project, is the third in a series of seven storage tunnels constructed under Project Clean Lake, the Sewer District’s 25-year, $3 billion program to drastically reduce the amount of combined sewage entering local waterways during heavy rain events (this is referred to as a combined sewer overflow).
Over the last 10 years, we’ve faithfully advanced the clean-water cause, says Sewer District CEO Kyle Dreyfuss-Wells.
“Since the start of Project Clean Lake in 2011, the Sewer District’s goal is to reduce combined sewer overflows from 4.5 billion gallons to less than 500 million gallons annually by 2036, and the completion of the Doan Valley Tunnel will help our community reach that goal,” Dreyfuss-Wells explained.
To date, the Sewer District has eliminated more than one billion gallons of combined sewer overflow and anticipates the elimination of an additional 665 million gallons by 2023.
The Sewer District will have reduced combined sewer outfalls from 126 to 112 by the end of this year thanks to Project Clean Lake progress and other capital investments.
Just the same way as DVT, Euclid Creek — the first tunnel built under Project Clean Lake — the Dugway Storage Tunnel, and Easterly Tunnel Dewatering Pump Station were constructed and are currently in operation. These three projects represent a $416 million investment in clean water, reducing the amount of combined sewage discharging into the environment during heavy rain events by hundreds of millions of gallons each year.
Recently, the Sewer District and its consultant, Mott MacDonald & Stantec, won the American Council of Engineering Companies’ Ohio Engineering Excellence Grand Award for this tunnel system. The award celebrates engineering projects demonstrating significant uniqueness, ingenuity, and value.
“It takes significant expertise and skill to execute projects of this magnitude and complexity,” said Dreyfuss-Wells. “The Sewer District is fortunate to have a such an amazing team to led and manage these large-scale projects that will benefit the community and environment for years to come.”
The Westerly Storage Tunnel ($135 million) is currently under construction, expected to be completed by 2022 with its associated pump station complete by early 2023. The WST system will help control overflows at two locations along the Cuyahoga River and reduced combined sewer overflows to the environment by nearly 300 million gallons per year.
The three remaining tunnels yet to be constructed include, Southerly ($325 million), Big Creek ($220 million), and Shoreline ($201 million). Construction of the Shoreline Tunnel, which begins this summer, was recently awarded to McNally/Kiewit SST Joint Venture.
Extending from Forrest Hills Park to E. 55th/Fairlie Avenue, the three-mile Shoreline tunnel will be 75 feet to 140 feet underground, and 23 feet in diameter. It will control overflows at 11 locations along Lake Erie and reduce combined sewer overflows by 370 million gallons every year once complete in 2025.
All Project Clean Lake work, including the seven tunnels, will be completed by 2036.
About Combined Sewer Overflows (CSOs)
Greater Cleveland’s earliest sewers (primarily within the City and its inner-ring suburbs) are combined sewers. Built around the turn of the 19th century, these sewers carry sewage, industrial waste, and stormwater in a single pipe.
During heavy rains, there is a dramatic increase of water flowing through the combined sewers. When this happens, control devices may allow some of the combined wastewater and stormwater to overflow into area waterways — such as Lake Erie and Euclid Creek — to prevent urban flooding. This event is called a combined sewer overflow, or CSO, and harms our clean water environment.
We estimated CSOs were discharging 9 billion gallons of combined sewage into the local water bodies every year in 1972. Through decades of investment, the Sewer District reduced the annual volume to about 4.5 billion gallons. At the conclusion of Project Clean Lake, the Sewer District will have reduced discharges to less than 500 million gallons.
Is clean water worth the investment? We’re feeling that way.