The hydrological cycle is far from being a stationary process and always experienced changes in the past. In recent years it seems that both climate and anthropogenic factors are accelerating the variability of meteorological and also hydrological processes. Starting from examples and long-term data on processes influencing coastal dynamics in the Red River (China-Vietnam), it will be shown first how anthropogenic factors, as reservoir impoundment, can dramatically reduce up to 80%, on average, of suspended sediment load downstream. Another anthropogenic factor, as land-use change may increase suspended sediment load up to 28% Considering climatic projections, instead, downstream in the Red River delta it can be expected that by the year 2050, with a projected decrease of rainfall by 3-5% in the dry season and an increase of temperature of about 1.2-1.5 °C, water deficit severity would increase by 7-8% and its intensity by 2.5-3.0%, relative to actual conditions, thus influencing potential saline intrusion from the sea. These results will be compared with similar evidences collected worldwide on climate- and humaninduced changes in the hydrological cycle, water management and engineering.
CLIMATE AND ANTHROPOGENIC CHANGE IMPACT ON THE HYDROLOGICAL CYCLE, WATER MANAGEMENT AND ENGINEERING
RANZI, Roberto
2012-01-01
Abstract
The hydrological cycle is far from being a stationary process and always experienced changes in the past. In recent years it seems that both climate and anthropogenic factors are accelerating the variability of meteorological and also hydrological processes. Starting from examples and long-term data on processes influencing coastal dynamics in the Red River (China-Vietnam), it will be shown first how anthropogenic factors, as reservoir impoundment, can dramatically reduce up to 80%, on average, of suspended sediment load downstream. Another anthropogenic factor, as land-use change may increase suspended sediment load up to 28% Considering climatic projections, instead, downstream in the Red River delta it can be expected that by the year 2050, with a projected decrease of rainfall by 3-5% in the dry season and an increase of temperature of about 1.2-1.5 °C, water deficit severity would increase by 7-8% and its intensity by 2.5-3.0%, relative to actual conditions, thus influencing potential saline intrusion from the sea. These results will be compared with similar evidences collected worldwide on climate- and humaninduced changes in the hydrological cycle, water management and engineering.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
