| The Tibetan Plateau is located in the joint area of water vapors came form Indian Ocean and South China Sea.Complex geographical and climate conditions made this region a "starter" and "amplifier" for global climate change.During the rencent decades,water problems such as glacier melting,lake expansion and flash floods caused by temperature rising have become serious.And ecological degradation,environmental pollution and other ecological problems have become increasingly prominent under unreasonable human activities.These ecological and water problems have seriously affected the ecological security and water security in this region,and also became the main shackles of the social and economic development here.Under the background of climate change,"How the water and soil resources evolved?What interactions are between them?How to regulate them?" are waiting to be solved urgently.This study selected the "natural-artificial" dual water cycle as the theoretical guidance,came up with the theoretical framework and the key technologies of the joint regulation of water and soil resources in the alpine region.And then chose the core area of ecological barrier construction in eastern Tibet,the Naqu River Basin as the study area,combined the statistics with laboratory experiment in order to identify the interactions between the water and soil resources.This study also used the prototype observation,laboratory experiment,RS,GIS,stastics and other theoretical and technical methods to find out the evolution characteristics of the water and soil resources.On the basis of the study above,this study constructed a joint regulation model of water and soil resources based on the System Dynamics method and a fuzzy comprehensive evaluation model to recommend the superior scheme and propose the guarantee measures.The main conclusions of this study are as follows:(1)According to the multi-process analysis of evolution characteristics of water resources,the annual precipitaion and the annuanl average temperature of the Naqu River Basin showed a significant upward trend during the 1995-2013 period.The annual average runoff simulated by WEP model also showed an increasing trend.This study chose five Global Climate Modesl(GFDL-ESM2M,HadGEM2-ES,IPSL-CM5A-LR,MIROC-ESM-CHEM,NorESM1-M)to estimate the temperature and precipitation.The multi-models average results showed that,in the scenarios of RCP2.6,RCP4.5 and RCP8.5,the annual average temperature and the annual precipitation during 2020-2050 period will keep increasing.The vegetation coverage of the basin decreased significantly with fluctuation in the past 5 years.During 1980~2014,both the richness and the degree of fragmentation of the landscape types decreased with the change of grassland coverage types from high and medium to low.(2)The results of the indentification of interaction mechanism between water and soil resources showed that,vegetation played a significant role in reducing water.With the increase of vegetation coverage,surface roughness coefficients increased.The results of control experiment indoor and the stastics indicated that,with the increase of vegetation coverage,the beginning time of runoff generation delayed,the runoff amount,coefficient,and rate decreased.It also showed that,the beginning time of infiltration and the response time of soil water to rainfall both increased with the increasing of vegetation coverage.(3)According to the ecological,environmental and resource characteristics of the Naqu River Basin,this study built a joint regualation model of water and soil resources,which was composed of subsystems of social-economic,resource,and environment.This study chose the different land use types and water users as the regulation unit,added the ecological water and ecological land use modules,used the Markov model to predict the land use to calculate the ecological water demand of different types of ecological land in different years.selected the CN value in the SCS model to calculate the storage of various types of ecological land.In addition,set the water supply and demand ratio as the constraints for sustainable development and utilization of land use and social-economic development,which achieved a dynamic joint control of water and soil resources.During the validation periods from 2000 t0 2014,simulation error of each variable was within ±10%basically,which meaned that the joint regulation model had a good simulation result.The sensitivity parameters included ecological land area,utilization rate of water resources,water amount for ecological demand,water utilization coefficient of irrigation,reuse rate of recycled water and other sensitivity parameters.(4)A fuzzy comprehensive assessment system was built composed by four criteria,which were supply-demand-allocation rationality of water resources,allocation rationality of soil resources,social and economic development rate,ecological and environmental benefits.The schemes including status continuation scheme,increased source scheme,industrial structure adjustment scheme,comprehensive scheme and joint scheme was evaluated by the model and found that joint regulation scheme was the superior scheme,in which the GDP of 2030 in the basin will be 4.35 times higher than that in 2015.Water supply-demand contradiction and the overloading problem will be eased.The pollutant emissions are within reasonable thresholds.The research results of this study will furhter improve the "natural-artificial" dual water cycle theory,the theoretical framework and the key technologies of the joint regulation and the indentification of interaction mechanism between water and soil resources in the alpine region,which also will provide scientific basis for development and utilization of water and soil resources in the Naqu River Basin. |
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