In 1984, Libya began building a 4,000-kilometer “river” beneath the Sahara; decades later, the incomplete network still supplies millions with water

Libya is one of the driest countries on Earth, but beneath its desert lies a network of underground pipes, some 4,000 kilometers long, built to carry ancient water from the deep south to the crowded coastal cities in the north. According to the Middle East Institute's recent analysis of the project, Libya's Great Man-Made River, which still supplies a large part of the country’s population, is incomplete and vulnerable more than four decades after ground was first broken. For Americans watching groundwater levels drop across the Southwest, Libya's gamble is worth paying attention to.

Why Libya built it in the first place
In the 1960s, Libya experimented briefly with desalination of seawater. This approach, according to the Middle East Institute, lost priority when Muammar Gaddafi came to power in 1969, and attention turned to the country’s underground aquifers. The same analysis points out that Gaddafi’s government promoted the idea that Libya had an almost unlimited supply of groundwater, a claim that helped justify years of heavy use with little planning for what would happen when it ran out.


There was one problem: that water was hundreds of kilometers away from where people lived. The population of Libya was clustered along the northern coast while aquifers were in the far south. Rather than moving cities or building more desalination plants on the coast, the government chose a third option: moving the water itself. Feasibility studies were carried out through the 1970s, and the pipeline network went into operation in 1984. Crews built concrete pipes about 13 feet across, wide enough to drive a small car through. They drilled more than 1,300 wells, many about 1,600 feet deep, to feed water into the system.

The water is older than it looks
That water flowing through those pipes isn't rainfall. This is what hydrologists call fossil water, moisture that seeped into the ground during a much wetter period of the Sahara's history and has remained trapped there ever since. It is drawn from the Nubian Sandstone Aquifer System, a reservoir shared by Libya, Egypt, Sudan and Chad. It’s the largest known non-renewable groundwater system on the planet, meaning it’s not being refilled anywhere near the rate it’s being pumped out, according to a peer-reviewed study in the Hydrogeology Journal co-authored by U.S. Geological Survey researchers.

Getting water to where people actually live
The first segment of pipeline reached the coastal city of Benghazi in 1991, according to Encyclopedia Britannica's account of the project. In 1996, a second branch reached the capital, Tripoli. That matters because most Libyans live along this northern coastline. The Middle East Institute notes that about 78.2 percent of the country’s population lives in these urban coastal zones: 5.38 million of the 6.8 million people who lived in Libya in 2020.

What's gone wrong along the way
Maintaining the system hasn’t been easy. The Middle East Institute said the authority running the project suspended its long-term strategic plan in 2019, when armed fighters attacked parts of the network during a military offensive on Tripoli, cutting off water to the capital and showing how easily a water system can be weaponized in conflict. Maintenance and repairs resumed after that offensive ended in 2020, but with long-lasting delays.

The same analysis adds that Libyan authorities have not fully taken into account how climate change could affect the aquifer over time, even though the network already shows signs of long-term overuse.

Why this matters beyond Libya
This story isn’t unique to Libya. Parts of the American Southwest also rely on ancient, slow-replenishing groundwater, and it’s being pumped faster than nature can replace it. Libya’s experience tells us what happens when a country builds its water future on a resource that doesn’t come back, once it’s gone, on any timeline that matters to us.

What comes next
The project will probably need stronger legal protections for contractors and clearer ways to resolve disputes to move forward, on top of the funding and political stability it has lacked for years, according to the Middle East Institute. Until then, the Great Man-Made River keeps running, unfinished, aging, and still central to millions of people's daily lives.