Workers in Mexico City's mega-tunnel. Workers in Mexico City's mega-tunnel.

Sewer, drain tunnel has doubled in cost

Mexico City's mega-tunnel is also at least six years behind schedule

The cost of a massive new sewage and storm drain tunnel for greater Mexico City has more than doubled since it was first announced in 2008, yet the project is still unfinished and millions of residents in the capital remain at the mercy of flooding.


The original cost projection for the main engineering project of the Túnel Emisor Oriente (TEO or Eastern Emission Tunnel) was just under 9.6 billion pesos (US $511 million) but that figure has now risen to over 20.1 billion pesos (US $1.07 billion).

After adding expenses incurred through sub-contracts, the Federal Auditor’s Office (ASF) found that almost 43.9 billion pesos (US $2.3 billion) were spent on the project between 2007 and 2016.

In the results of its 2016 public accounts audit, the ASF attributes the budget blowout to the absence of an overarching executive plan to manage the project, which allowed contracts to be modified. Contracts have been modified four times since the project began, the ASF confirmed.

Five different companies were initially awarded direct contracts to complete the tunnel although ultimate responsibility lies with the National Water Commission (Conagua). The ASF presented five recommendations to Conagua and urged it to take action against those responsible for the project’s shortcomings.

In addition to cost overruns, the huge infrastructure development has also been plagued by delays and the completion date has been pushed back on several occasions. The project was originally slated to be finished in 2012.

The most recently revised completion date of August 2018 is also at risk of being missed, the ASF warned.


The 62-kilometer-long mega-tunnel, running from the Remedios river in the northeast of the metropolitan area to the Atotonilco water treatment plant in the state of Hidalgo, has been described as the world’s largest sewer project and was designed to significantly increase Mexico City’s capacity to drain storm and wastewater.

The infrastructure is desperately needed to alleviate frequent flooding that plagues Mexico City during the rainy season.

While one 10-kilometer section is already in operation, the fact that the project remains largely incomplete means that the pressure on existing drainage infrastructure has not been significantly eased.

The failure to rectify the problem, despite the huge financial outlay, leaves 22 million people in the metropolitan area vulnerable to the threat of flooding, the ASF said.

Mexico city’s drainage system has failed to keep up with rapid population growth despite efforts to increase its capacity although blockages caused by garbage are also to blame for the frequent flooding that wreaks havoc on the capital.

Source: Milenio (sp)

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  • tito

    so, in the world’s biggest and most expensive sewer, you make it a combined drain and make for much more sewage contaminated water. That too can be mitigated without tearing houses and roof drains out and installing storm drains. Settling ponds will do lots to lessen the negative impact of sewage that doens’t need to be sewage.