Egypt built the Aswan High Dam to tame the Nile's floods, but scientists now say the project starved the delta of fertile sediments and accelerated coastal erosion
The Nile River shaped life in Egypt for thousands of years. Every year, due to rains in the distant Ethiopian highlands during the summer, there was a tremendous amount of water that flowed through the desert toward the north. This phenomenon was often regarded as a great gift. The floodwaters carried black, nutrient-rich volcanic silt.
As the twentieth century advanced, the need to protect a growing population from floods and droughts drove a major engineering shift. The solution was to control the river's flow more closely. By erecting a monumental barrier in the southern part of the country, authorities reduced seasonal volatility, secured a more stable water supply, and generated electricity for industrial development.
However, one downside is serious environmental damage downstream from the dam. In fact, the findings of the thorough analysis conducted on the history of the matter, featured in the Open Journal of Soil Science, highlight negative downstream effects of the dam.
Landscape deprived of its building blocks
Indeed, the essence of the problem lies in the fact that the huge rock-filled barrier does an overly effective job of blocking the river's flow. As silt-laden water from upstream reaches the reservoir behind the dam, its flow slows, and sediment settles out. As the water slows, the fertile sediment it carries settles to the bottom of the reservoir.
Before the construction of the modern barrier, the river reliably transported an estimated forty million tonnes of rich sediment to the lower basin every single year. Today, that sediment flow has been greatly reduced. Without the annual deposition of this fresh, volcanic silt, the agricultural fields along the banks have rapidly lost their natural productivity. To compensate for this sudden loss of nutrients, farmers have been forced to rely heavily on artificial chemical fertilisers, which have gradually degraded the structural health of the soil and led to significant runoff pollution in local waterways.
The problem becomes even worse where the river meets the sea. A research report titled Modeling the Impact of controlled flow and sediment releases for the restoration of the Nile Delta, Egypt, provides additional information concerning the harsh physical effects of a lack of mud on the coast of northern Egypt. According to the findings, the northern coast of the delta faces two dangers at once now. Because less muddy river water reaches the Mediterranean, coastal currents erode the sandy shoreline more quickly.
Sinking northern delta and rising sea level
In addition to coastal erosion, there is another dangerous phenomenon called land subsidence. The delta's older sediments have compacted for millennia under their own weight. In the past, this natural land sinking process could be offset by the natural sedimentation of new layers of mud from the river. Now that the sediment supply has been cut off, land subsidence continues.
As the twentieth century advanced, the need to protect a growing population from floods and droughts drove a major engineering shift. The solution was to control the river's flow more closely. By erecting a monumental barrier in the southern part of the country, authorities reduced seasonal volatility, secured a more stable water supply, and generated electricity for industrial development.
However, one downside is serious environmental damage downstream from the dam. In fact, the findings of the thorough analysis conducted on the history of the matter, featured in the Open Journal of Soil Science, highlight negative downstream effects of the dam.
Landscape deprived of its building blocks
Indeed, the essence of the problem lies in the fact that the huge rock-filled barrier does an overly effective job of blocking the river's flow. As silt-laden water from upstream reaches the reservoir behind the dam, its flow slows, and sediment settles out. As the water slows, the fertile sediment it carries settles to the bottom of the reservoir.
Before the construction of the modern barrier, the river reliably transported an estimated forty million tonnes of rich sediment to the lower basin every single year. Today, that sediment flow has been greatly reduced. Without the annual deposition of this fresh, volcanic silt, the agricultural fields along the banks have rapidly lost their natural productivity. To compensate for this sudden loss of nutrients, farmers have been forced to rely heavily on artificial chemical fertilisers, which have gradually degraded the structural health of the soil and led to significant runoff pollution in local waterways.
The problem becomes even worse where the river meets the sea. A research report titled Modeling the Impact of controlled flow and sediment releases for the restoration of the Nile Delta, Egypt, provides additional information concerning the harsh physical effects of a lack of mud on the coast of northern Egypt. According to the findings, the northern coast of the delta faces two dangers at once now. Because less muddy river water reaches the Mediterranean, coastal currents erode the sandy shoreline more quickly.
Sinking northern delta and rising sea level
In addition to coastal erosion, there is another dangerous phenomenon called land subsidence. The delta's older sediments have compacted for millennia under their own weight. In the past, this natural land sinking process could be offset by the natural sedimentation of new layers of mud from the river. Now that the sediment supply has been cut off, land subsidence continues.
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