Thousands of years ago, a great civilization arose in Egypt. A large society came together and worked on massive projects. They dug huge irrigation basins and created new technology for agriculture, such as the plow. They produced great works of art and architecture, such as the pyramids and the great Sphinx.

How could this have happened, thousands of years ago, in a country which is mostly desert?

The people of Egypt have been able to prosper since ancient times because of the wealth the Nile River brings them.

The Nile River of Africa is the longest river in the world (6,650 km or 4,132 miles). It originates in the highlands of eastern Africa and flows downhill (to the north) until it reaches the Mediterranean Sea (see map). The watershed of the Nile is huge. It drains an area that is about one-tenth (1/10) of Africa (2,850,000 km2 or 1,100,000 square miles).

For thousands of years in Egypt, the Nile floodplain (area of level land on either side of the river prone to being flooded) and delta (area at the mouth of the river at the coast) were very fertile. Every year in autumn, heavy rains would erode soil throughout the watershed of the Nile. Once the rains began, the river would flood in Egypt, bringing with it rich soil sediment from throughout the watershed. The sediment settled out of the water, and made the land of floodplain and delta fertile for farming. Farming in these areas was very successful, and the people prospered.

Today, farming is not as prosperous in the floodplain and delta of the Nile River. The river and its sediments no longer fertilize this area because of human efforts to stop the flood with dams.

In the 1960's, the Egyptian people (with international aid) built another huge architectural feat: the Aswan High Dam. The dam, built in southern Egypt, has several purposes. It regulates river levels, controls water releases for irrigation, and generates hydroelectric power (an inexpensive source of electricity). Thus, as a result of this dam, river water and rich sediments no longer overflow onto the floodplain and delta. Mother Nature can no longer fertilize these areas every year.

The water upstream of the dam is now stored in two artificial lakes, Lakes Nasser and Nubia (just south of the dam).

Although the dam achieved its goals of controlling water flow and generating inexpensive electricity, it created many problems. When the dam was first built, the river upstream flooded. Many ancient statues were lost or submerged. Today, there is a sediment problem in the storage lakes upstream. Now that most of the floodwater is contained in Lake Nasser, most of the sediment in the floodwater is settling out and slowly filling the lake. This means eventually there won't be any more storage room left in the storage lakes! Also, because the water stands still in the lakes for long periods of time, evaporation of river water has increased greatly. This is a serious concern in the hot, dry climate of Egypt.

Environmental changes caused by the dam affect the floodplain and delta, too.

The water level downstream of the dam is now lower. The banks of the river are exposed and experiencing steady erosion.

There is less sediment in the river water. Clearer water allows more sunlight, and phytoplankton grows more abundantly (by photosynthesis). Now, more chlorine has to be used at water treatment facilities. The increase in phytoplankton has also thrown off the balance of the food web. It has had a negative impact on fishing in the river, an important economic resource.

Less sediment reaches the delta. Now, soil lost to coastal erosion is no longer being replaced with floodwater sediment. The delta is receding, and more saltwater is reaching upstream. This salty water contaminates farmland and groundwater. Also, as the delta erodes, important coastal fisheries disappear.

Now that water for irrigation can be released from the dam year-round, the land is suffering from being over-farmed. Artificial fertilizers have to be added to the land. These are often applied improperly (too heavily), and the excess chemicals end up washing into the river and seeping into the groundwater.

On a last note, the building of the Aswan High Dam has also disturbed the fragile ecosystem of the Mediterranean Sea. The large influx of nutrients associated with the annual flood no longer reaches the coast. This has affected the food web of the sea, and has had severe affects on the sardine and shrimp industry, important economic resources.

Thus, farming in Egypt is no longer as prosperous as it once was. Although the Aswan High Dam has brought benefits to the area, it has also caused many environmental problems.