Streamflow Changes in the Nile River could have Negative Effects on Agricultural Water Use and Hydropower Production

The Nile River is the longest international river system in the world, and significantly impacts agriculture, energy, and local and regional economies. Beyene et al (2009). studied the effects of climate change on the streamflow of the Nile River using eleven General Circulation Models (GCM’s) and two IPCC climate change scenarios. The study concluded that the Nile would experience an increase in streamflow early in the century, but mid- and late century predictions expect declines. The data implicate declines in availability of agricultural water resources by the second half of the century, as well as uncertainty toward energy production at the High Aswan Dam (HAD). Bailey Hedequist
Beyene, T., Lettenmaier, D.P., Kabat, P., 2009. Hydrologic impacts of climate change on the Nile River Basin: implications of the 2007 IPCC scenarios. Climatic Change 100: 433–461. Ferrara, M.R., Trevisol, P., Acutis, M., Rana, G., Richter, G.M., Baggaley, N.. 2009. Topographic impacts on wheat yields under climate change: two contrasted case studies in Europe. Theoretical and Applied Climatology 99, 53–65.

Tazebe Beyene and colleagues at the Department of Civil and Environmental Engineering at the University of Washington conducted a study to predict how streamflow on the Nile River will be affected by climate change in the next century. The data were collected by using 11 General Circulation Models and two climate change scenarios taken from the 2007 IPCC Fourth Assessment Report. Global emissions scenarios were chosen for this study based on their popularity within climate change studies. These scenarios were the IPCC A2 and B1 scenarios; A2 represents a world with high population growth, and slow economic development while B1 represents a world which uses green technology, has slow population growth, and rapid economic growth. In the A2 scenario, global CO2 emissions are predicted to reach 850 ppm by 2100, while the B1 scenario predicts increases of CO2 levels to stabilize at 550 ppm by 2100. Results from the 11 GCM’s and the two climate scenarios were then used in the Variable Infiltration Capacity (VIC) hydrology model, a model which produces streamflow predictions when matched with climate predictions and data collected at the HAD. The VIC creates a scenario for the Lake Nasser reservoir, created by the HAD and a major source for irrigation supply. Simulating future changes at Lake Nasser creates a clearer picture of potential impacts on agriculture and hydropower production.

The results showed that, on average, it is expected that the Nile will experience increases in flow at the beginning of the century, but by mid-century river flow will decrease due to expected changes in precipitation and an increase in evaporation. Predictions for hydropower production fluctuate, increasing at the beginning of the century and declining mid-century onward under the A2 scenario. Irrigation supply is predicted to dramatically decrease in Egypt by the end of the 21st century. The study concluded that as much as 457,000 ha of irrigable land may be lost to Egypt by the end of the 21st century, and that irrigation will be more highly affected than hydropower. Population growth within Egypt suggests that loss of water supply for the region could cause a future crisis in the country. 

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