Assessment of ecologically relevant hydrological change in China due to water use and reservoirs

摘要

As China's economy booms, increasing water use has significantly affectedhydro-geomorphic processes and thus the ecology of surface waters. A largevariety of hydrological changes arising from human activities such asreservoir construction and management, water abstraction, water diversionand agricultural land expansion have been sustained throughout China. Usingthe global scale hydrological and water use model WaterGAP, natural andanthropogenically altered flow conditions are calculated, taking intoaccount flow alterations due to human water consumption and 580 largereservoirs. The impacts resulting from water consumption and reservoirs havebeen analyzed separately. A modified "Indicators of Hydrologic Alteration"approach is used to describe the human pressures on aquatic ecosystems dueto anthropogenic alterations in river flow regimes. The changes in long-termaverage river discharge, average monthly mean discharge and coefficients ofvariation of monthly river discharges under natural and impacted conditionsare compared and analyzed. The indicators show very significant alterationsof natural river flow regimes in a large part of northern China and onlyminor alterations in most of southern China. The detected large alterationsin long-term average river discharge, the seasonality of flows and theinter-annual variability in the northern half of China are very likely tohave caused significant ecological impacts.