Ebro Delta - importance of water movement and sediments

The Ebro Delta is one of the main deltas of the Mediterranean. Development of the present plain probably began about 4,000 years ago and since then river sediments have created some 330,000 ha of coastal wetland. Today some 57% of the area is given up to rice cultivation. The progressive increase in the number of reservoirs in the catchment area (especially in the 1960s when two large reservoirs were built) has resulted in the retention of 99.9% of the sediment formerly reaching the sea. The consequences for the delta are considerable especially under a scenario of rising sea levels. Today some 40% of the wetland is < 0.5m above mean sea level and a small area below it. It is predicted that by the end of this Century some 50% of the delta could be below sea level. This has important implications for the rice cultivation industry, water resources (drinking water in the area is already slightly brackish) and the considerable nature conservation value of the area. Currently engineering solutions are being presented as the means of protecting the area. Other voices suggest that this is no long term solution and that the sediment currently trapped in the reservoirs, if released, would provide a more sustainable approach to reversing the sinking of the delta (Ibanez et al. 1997).

References

Ibanez, C., Canicio, A., Day, J.W. & Curco, A. 1997. Morphological development, relative sea level rise and sustainable management of water and sediment in the Ebre Delta, Spain. Journal of Coastal Conservation, 3/2., 191-202. Abstract...