DUBAI, United Arab Emirates — The boring machine lowered into a shaft beside the Al Khail Road on Sunday is 11 meters across and will spend the next three years cutting a tunnel beneath the city to carry something Dubai spent decades assuming it did not need to plan for: rain.
The emirate began construction of the main section of its Tasreef stormwater network, a 30-billion-dirham, or $8.2 billion, system of deep tunnels and pumping stations that the municipality says will increase the city’s drainage capacity by about 700 percent when completed in 2033. The project was approved after the storm of April 2024, when 254 millimeters of rain fell in 24 hours, nearly double the annual average, flooding major highways, closing the airport for two days and leaving neighborhoods without road access for a week. Insurers estimated losses at $2.4 billion.
“Dubai was built for 20 millimeters a year, with a design standard that treated 100 millimeters as a once-a-century event,” said Eng. Mariam al-Mazrouei, director of the municipality’s drainage department, at the ceremony. “We have now had three such events in six years. The century has become a decade.”
The main tunnel will run 29 kilometers from the Jebel Ali industrial district to an outfall in the Gulf, at depths of up to 60 meters, and will be fed by secondary tunnels in the districts that flooded worst in 2024, including Jumeirah Village and Al Quoz. Its capacity, about 20 million cubic meters of water a day, is modeled on Tokyo’s underground discharge channel and on a system in Kuala Lumpur that doubles as a motorway in dry weather. Dubai’s version will not carry traffic, though the municipality has suggested the pumping stations could be used to store treated water for irrigation.
Meteorologists say the increase in extreme rainfall in the Gulf is consistent with a warming atmosphere that holds more moisture, and that the region, while remaining arid on average, is likely to see rain concentrated in fewer and heavier events. The U.A.E. national weather center reported that the three wettest days in the country’s recorded history have all occurred since 2016.
The project is also a reckoning with the way Dubai was built. Much of the city rose in the 2000s on compacted sand with minimal grading, and developers were permitted to connect drainage to a network sized for a city a fraction of the current size. A study commissioned by the municipality after the 2024 storm found that about 40 percent of the city’s road network had no functioning storm drains at all and that water in low-lying districts had nowhere to go but into parking garages. Several developers have since been required to retrofit drainage at their own expense.
For residents, the tunnel is reassurance with a long delivery date. Priya Nair, 39, who lives in Jumeirah Village Circle and spent four days in 2024 unable to leave her building, said she had bought a second car with higher clearance. “They are building the right thing,” she said. “I am just not going to sell the car until it is finished.”
Ms. al-Mazrouei said interim measures, including 150 mobile pumps and 40 kilometers of surface channels, would be in place before this winter. The forecast for the season, she noted, was for above-average rainfall.
A version of this article appears in print on Oct. 12, 2026, Section A, Page 11 of the European edition with the headline: Dubai Breaks Ground on an $8 Billion Stormwater Tunnel So a Single Day of Rain Cannot Stop the City Again.
