de Araujo, J. C. ， Landwehr, T. ， Alencar, P. H. L. ， Paulino, W. D.
2023-01-01 JOURNAL OF SOUTH AMERICAN EARTH SCIENCES 2023 121(卷), null(期), (null页)
The semiarid State of Ceara, Brazil, implemented its water management system in the early 1990s. The drought -prone State is densely populated and its supply strongly relies on surface reservoirs, whose yield reduces with silting. Using artificial neural networks and data from 141 monitored dams, we show that the silting ratio of the reservoirs significantly enhanced after the implementation of the water management system. An explanation for this fact is that, since the management started, water withdrawal increased, leading to lower reservoir levels at the beginning of the rainy season. This reduces the probability of spilling, which is the main mechanism of sediment outflow, thus causing excessive siltation. As a result, water availability is expected to reduce by 6% in 30 years, creating a clear contradiction with the management objectives. To tackle this problem, four actions are recommended: to include spilling in the operational rules, to reduce erosion in the basins, to execute sediment reuse policy, and to implement water-demand management.