Sediment deficit in rivers caused by dams and instream gravel mining: a review with examples from NE Spain

摘要: Rivers carry sediment almost continuously from headwaters to deposition zones. Dams and gravel mining interrupt such continuity, causing severe damages downstream fluvial coastline ecosystems. Sediment deficit is not only an environmental issue, but also a socio-economic problem. Sediment captured by reservoirs reduces their capacity store water, infrastructures in rivers beaches are strongly affected lack of sediment. deficit its effects illustrated this report with examples NE Spain, focusing on the Ebro River the Catalan Coastal Ranges Eastern Pyrenees. Over long-term, sound programmes must be definitively implemented monitor transfer river systems changes over time. But, meantime, short-term correction steps should undertaken, including a) for gravel mining, prohibition in unbalanced rivers, especially reaches of dams, adding costs into the price product (aggregate), exploring alternative sources aggregate (concrete recycling, reservoir deposits), and b) regulated sediment-pass through reservoirs during high flows, mechanical removal from together flushing flows artificial nourishment downstream, prevent (or restore) lost fish habitat delta regression.