| Observed climate and hydrological change and variability indicated that both average and extreme hydrological chracteristics have changed a lot.With the awareness and enhancement of environmental protection of river health and river ecology, environmental flows research has attracted national rivers and water administrators, managers, researchers, environmental flows research has gradually become a hot topic of multidisciplinary experts.Jiangxi meteorological disasters have many kinds of high frequency, wide distribution. In many years, different levels of meteorological disasters, droughts and floods posed the great threat to agricultural production, and development of economy, exacerbated by the impact of extreme weather and climate. There are five large rivers, named as Gan river, Fu river, Xin river, Rao river, Xiu river and many middle&small rivers in Jiangxi Province. Recent year’s drought in Jiangxi get worse and last longer time.Jiangxi Province has planned construction of lake controlling engineering, which will have direct influence to downstream of Yantze river.Especially in extreme climate scenes,the engineering and its management will influence livelihood, production, environment and ecology.Thence, this research has theoretical and real meanings.In this paper, Jiangxi Province and its typical watersheds were studied by the use of RS, GIS, hydrological modeling, time series analysis, Markov analysis techniques and methods of extreme climatic drought index, dry season rainfall, hydrological responses and hydrological alterations.1. Calculated extreme climate index, analyzed the temporal and spatial features and variation of extreme climate for many years, according to historical data of precipitation and temperature in Jiangxi Province with software RClimdex. 2. Calculated the Standardized Precipitation Evapotranspiration Index (SPEI), analyzed characteristics of temporal pattern of drought in Jiangxi Province with Empirical Orthogonal Function method (EOF)3. Using Ensemble Empirical Mode Decomposition (EEMD), Weighted Markov method to analyze and predict the dry season precipitation trends in the north partof Jiangxi Province.4. Using distributed hydrological model(SWAT), combined with GIS technology to simulate runoff response to climate change of severe drought in the Xinjiang River basin. Particular drought year was selected and designed, the year’s hydrological status were simulated and compared with observed flows in2003.5. Investigated multi-scale characteristics of continuous drought and constant low runoffs by mulitiplied methods which included Counting method of consecutive days without effective rain, SPEI index analysis, EEMD signal analysis, Wavelet analysis, etc. The responsing relationship between the continuous drought and the continuous low flows in Ganjiang river were explored.6. Calculated the hydrological alteration of Ganjiang basin and Xiushui basin under the influence of dam constructions according to the Indicators of Hydrologic Alteration (IHA) model, hydrological alteration in both middle and low range of flows were calculated Espatially Compared and discussed Different combination of employment time of reservoirs.Overall, by exploring the chracteristics and possibility of drought scenarios in Jiangxi Province, invesgating the hydrological response of these scenarios, probing the hydrological alteration between the pre-and post-storage periods of reservoirs, proposing some suggestions for protection of water resources and ecological system and sustainable development of Jiangxi Province. The research will be of benefit to water conservation, ecosystem health, sustainable economic and social development in Jiangxi and even the downstream of Yangtze River Basin. |
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