Libya is located in the arid and semi-arid regions of the world and suffers from intense water shortage and poor water management. It is one of the driest countries in the world, with more than 90% of it desert land.
The project started in 1984 and was scheduled to be completed in 25 years. Feasibility studies showed that the GMMR project was more cost-effective compared to three other options of providing Libya with water: importing water by ships, desalination of seawater, or laying a pipeline from Europe.
After completion, it was projected to provide 6,500,000 cubic meters of freshwater per day from aquifers beneath the Sahara to the Northern cities of Libya bordering on the Mediterranean Sea, along a network of gigantic underground pipes. Around 6.5 million people live along Libya's Mediterranean coast, constituting around 70% of Libya's population. Coastal aquifers providing the northern cities with water have either dried or become unusable due to saltwater intrusion. Old desalination plants are in need of repair. 
The water comes from the South of the country, from the Nubian Sandstone Aquifer System, the largest fossil water aquifer in the world, covering an area of around two million square kilometers. The giant aquifer spans territories in Southern Libya, Sudan, Egypt, and Chad. The Nubian Sandstone Aquifer includes four freshwater basins within the borders of Libya that contain around 12,000 cubic kilometers of fossil water from the ice age buried as deep as 600 meters underground.
80% of the water provided by the GMMR would be dedicated to agriculture, and the remaining 20% to municipal and industrial use. After completion, irrigation water from the project would enable the cultivation of 160,000 HA of land.
The project was designed in five phases, largely separate in their design but making an integrated system in the end. It involved digging around 1,300 wells, some up to 600 meters deep. The project also involved constructing reservoirs and pumping stations.
The total length of the concrete pipelines is around 4,000 km with a 4m radius.
In 1983, the Great Man-Made River Authority was created by law No. 11/1983 by the general people's congress to implement and manage the GMMR project.
- The first phase of the project was inaugurated in 1991 and completed in 1996. This system supplies 2,000,000 cubic meters of water per day to Benghazi, the second-largest city in Libya, as well as Sirte, previously Gaddafi's stronghold.
- The second phase finished in September 2000, supplying one million cubic meters of water a day to Tripoli and Jeffara.
- The aim of the third phase was to expand phase I and increase the water provided by phase I by 1.68 million cubic meters per day, inaugurated by Gaddafi in 2010. It also provided water to Tobruk
- Phases 4 and 5 of the project are on halt due to the conflict in Libya. They involved extending the distribution network and integrating the Eastern and Western networks into a single system.
There are four major underground basins to provide the water resource:
1. The Kufra basin: in the Southeast near the Egyptian border, covering an area of 350,000 square kilometers, forming an aquifer of 2000 m deep and a capacity of 20,000 km squared within Libyan borders
2. Sirte basin: 600 m deep, holding an estimated of 10,000 km squared of water
3. Murzuk basin: south of Jabal Fezzan, 450,000 km squared, estimated to hold 4,800 Km cubes of water.
4. Hamadah and Kufrah basins: south of Libya
One problem with the GMMR is that the underground water is not renewable. Although Gaddafi's officials have claimed there is enough underground water to last 4,625 years according to current demand, others have warned that the water might run out within a 100 years . Others have estimated that the water will be exhausted in 50 years. 
The Great Man-Made Rive Water Utilization Authority is responsible for the use of the water for agricultural purposes. Fees are highly subsidized for farmers (0.62$/cubic meter), and modern drip irrigation techniques are used to minimize water waste.
The Secretariat of Municipalities is responsible for the water distribution to cities. More than 30% of the municipal water demand is provided by this project.
2% of the water is used for industrial purposes, mainly for the oil industry.
The International Atomic Energy Agency (IAEA) water resources program, the Global Environment Facility (GEF), and the United Nations Development Program (UNDP) have undertaken the joint Nubian Aquifer Project, the goal of which is to establish equitable management of the water resource between the Nubian Sandstone Aquifer System (NSAS) both for sustainable economic development of the relevant countries and the protection of biodiversity and land resources. It is one of the first international transboundary aquifer water projects.