A ceremony held in Central Park last October saw former New York mayor, Michael Bloomberg, announce the completion and activation of the final Manhattan stage of City Water Tunnel No. 3.

This 8.5 mile (13.7km)-long tunnel will reduce the City’s dependence on Water Tunnel No. 1, which will be taken offline for inspections and repairs for the first time since it began continuous operation in 1917.

However, as a whole, Tunnel No. 3 is still miles away from completion. And the market for sewage and water infrastructure is steadily growing.

To date, the New York City has invested USD 4.7bn in Tunnel No. 3 since construction began in 1970. The multiphase project had been planned for staged delivery when first proposed in 1954, and funding issues have slowed the project’s progress a number of times.

"The Third Water Tunnel is possible because of the hard work, dedication and sacrifice of thousands of men and women – planners, engineers, sandhogs, contractors and many others – who have labored for two generations to ensure that the City has a safe, reliable water supply now, and far into the future," said deputy mayor Cas Holloway, at the October ceremony.

Less than two weeks earlier in Washington D.C., the DC Water Board of Directors approved the construction contract to build the First Street Tunnel for a Skanska-Jay Dee joint venture. The USD 157M contract is for design-build of a 19ft- (5.8m)-diameter tunnel slated for completion in 2016. The tunnel will store 8 million gallons of stormwater, capturing it before it can make its way to the combined sewer system.

As part of the DC Clean Rivers project, a new 13-mile (20.9m) network of 23ft (7m) diameter tunnels, it’s just one of several tunnelling contracts including the Blue Plains Tunnel currently under construction, and the Anacostia River tunnel awarded in May 2013.

In a national perspective, according to data from Timetric, the value add of the sewage infrastructure construction in the US was USD 10.7bn in 2012, continuing to increase each year from USD 10bn in 2008. The market analyst company forecasts there will be even bigger gains, increasing some 23.8 per cent over the next five years. Water infrastructure construction in the US follows very similarly according to Timetric, and is also expected to make an increase of some 22 per cent from 2012 to 2017. In New York, large parts of the Bronx, Brooklyn, Queens and Staten Island are currently served by City Tunnel No. 2, which has been in continuous service since 1936. In 1993, work began on the 10.5-mile (17km) Brooklyn/Queens leg of Tunnel No. 3, which will provide a critical redundancy for Tunnel No. 2 when work is completed in 2021.

Stage Three of the project includes construction of 25km water tunnel also known as Kensico-City Tunnel from the Van Cortlandt Park Valve Chamber in Bronx to the Kensico Reservoir in Westchester County.

Stage Four of the project calls the construction of a 22km long tunnel, in which the water will be delivered to the eastern parts of the Bronx and Queens. This stage will extend southeast through the Bronx from the Van Cortlandt Park Valve Chamber. It will then travel under the East River into the Flushing area of Queens.

The construction of Tunnel No. 3 thus far has seen the excavation of more than 82 million cubic feet (25 million cubic metres) of soil, and some 30 million cubic feet (8 million cubic metres) of concrete has been installed to line the tunnels

CSO project updates
Aecom is working on the final design for the south storage tunnel in Hartford, Connecticut, which is likely to be 28ft in diameter and three-miles long. it is one of two storage tunnels, with the north tunnel planned for the third phase of the Metropolitan District commission’s clean Waters Project.

Construction is expected to be complete in December for phase two of the Narragansett Bay commission’s (nBc) cso plan in Providence, Rhode Island. The project comprises two interceptors along the Seekonk and Woonasquatucket rivers. Work is mainly microtunnelling for the 16,400ft (5km) long Woonasquatucket interceptor with a 1,800ft (549m) long tunnel adit, and the Seekonk interceptor, which will be 7,200ft long (2.2km). Phase three, which is slated to be a deep rock tunnel approximately 13,000ft (4km) long, is in preliminary design.