Nubian Sandstone Aquifer System

There is a lot of water deep under the sand.

This water is in the big, hot desert. It is found in four lands. It is under parts of Egypt and Sudan. It is also under Libya and Chad. This water came from rain a long time ago.

People use pipes to get the water. They use it to grow food. It is a very big supply of water. This water is a great help to the people there.

Deep under the Sahara desert lies a huge supply of water.

This is called a fossil aquifer. An aquifer is a place underground that holds water. This one is the largest in the world. It sits under four countries. These are Egypt, Sudan, Libya, and Chad. The water is trapped in hard sandstone rock. This rock is between 140 and 230 meters thick.

The water is very old. It came from rain a long time ago. One part of the water came from the Mediterranean. Another part came from the tropical Atlantic. This happened hundreds of thousands of years ago.

People use this water for many things. In Libya, they use the Great Man-Made River project. This project uses pipes to move the water.

They use the water for farms and for drinking. Each year, they take out about 2.4 cubic kilometers of fresh water. Many groups work together to study the water. They want to use it in a fair way. They also want to protect the land.

Deep under the Sahara desert lies a huge supply of water. This is called a fossil aquifer. An aquifer is a place underground that holds water. This one is the largest in the world. It sits under four countries. These are Egypt, Sudan, Libya, and Chad.

The water is held in hard sandstone rock. This rock layer is between 140 and 230 meters thick. The water is very old and is called meteoric water. This means it originally came from rain or snow. One part of the water came from the Mediterranean. This happened about 38,000 years ago. Another part came from the tropical Atlantic. This happened around 361,000 years ago.

People use this water for many important things. In Libya, they use the Great Man-Made River project. This project uses pipes to move the water.

They use it for drinking and for farms. Each year, they take out about 2.4 cubic kilometers of fresh water. This helps people live and grow food in the desert.

Scientists study the water to learn more about it. The aquifer covers over two million square kilometers. It holds about 150,000 cubic kilometers of groundwater. Since 2001, people have drilled in Egypt near Abu Simbel. They did this for a land reclamation project. This project helps turn dry land into useful land.

Many groups work together to protect this water. The International Atomic Energy Agency works with the four countries. They also work with the United Nations. Their goal is to manage the water in a fair way. They want to help the people and protect the land. This keeps the area healthy for a long time.

The Nubian Sandstone Aquifer System (NSAS) is the largest known fossil water aquifer system on Earth. An aquifer is an underground layer of rock or sediment that holds water. This specific system is classified as a fossil aquifer because the water is very old. It is located deep beneath the eastern end of the Sahara desert. The system is massive, covering a land area of just over two million square kilometers.

This vast underground reservoir spans the political boundaries of four different countries. These nations are Egypt, Libya, Sudan, and Chad. The NSAS is a vital resource for the future development of this region. It contains an estimated 150,000 cubic kilometers of groundwater. This water is essential for supporting life and economic growth in the desert. Because it spans multiple borders, the management of this water involves many different governments.

The geology of the aquifer is quite specific. It is largely composed of hard ferruginous sandstone. This means the sandstone contains iron. Within this sandstone, there are layers of shale and clay, which are known as intercalation. The thickness of this rock layer ranges from 140 to 230 meters. The groundwater within the system varies in quality. It can be fresh or slightly brackish, which means it has a small amount of salt. The salinity levels range from 240 to 1300 parts per million (ppm).

The water in the NSAS is described as being of meteoric origin. Meteoric water is water that originally came from precipitation, such as rain or snow. Scientists have identified two distinct recharge locations for this water. The first recharge event happened about 38,000 years ago and originated from the Mediterranean. The second recharge event occurred much earlier, around 361,000 years ago, originating from the tropical Atlantic. Over a very long duration of residence, the water has interacted with the surrounding rocks. This has caused high concentrations of sodium, chloride, and sulfates through leaching and dissolution of gypsiferous shales and clay.

Humanity uses this water through massive engineering projects. One notable example is the Great Man-Made River (GMMR) in Libya. This is the world's largest irrigation project. It uses a network of pipes to transport water from the aquifer. Through this project, Libya extracts an estimated 2.4 cubic kilometers of fresh water every year. This water is used for both human consumption and for agriculture. Such large-scale extraction helps provide food and water to desert populations.

In Egypt, intensive drilling and development have occurred since 2001. This work took place in the area between Toshka and Abu Simbel. These efforts were part of a land reclamation project. Researchers used drilling information to study the hydrogeological setting. They found that tectonic settings and lithological characteristics affect groundwater flow. These factors also impact the overall aquifer potentiality. In the Toshka and Abu Simbel area, the potentiality is considered relatively low compared to areas like Dakhla.

Because the NSAS is so important, international cooperation is necessary. Since 2006, the International Atomic Energy Agency (IAEA) has worked with the four NSAS countries. They participate in the IAEA-UNDP-GEF Nubian Project. This project includes partners like the United Nations Development Programme (UNDP) and UNESCO. The long-term goal is to establish rational and equitable management of the water. This means using the water fairly among all countries. The project also aims to advance socio-economic development and protect biodiversity and land resources in the region.