The Water Resources Of Tajikistan And Runoff Response To Climate Change

Tajikistan has abundant water resources, Water resources accounted for more than half of the total ofthe entire region of Central Asia. The total volume of the water resources of Tajikistan is about983.46km3,mainly distributed in the rivers, glaciers, lakes, reservoirs and underground. The surface water resourcesoccupies the6.15percent of total water resources, glaciers melting forms85.92percent of total waterresources, water resources in the lakes occupies the4.47percent of total water resources, total watervolume of reservoirs occupies the1.56percent of total water resources, groundwater resources occupies the1.90percent of total water resources.The global warming results in polar and alpine glaciers are retreating, sea-level is rising, precipitationpatterns and runoff is changing and so on, and this poses a serious threat to all mankind ecologicalenvironments and social and economic development. Tajikistan is an important water source region inCentral Asia, runoff mainly comes from snow and glaciers and it occupies the larger proportion. Study thehydrology process of the river of the country and the response of water resources to climate change has theimportant significance to study the impact of climate change on water resources in Central Asia, study theXinjiang mountain river glacier role and the river response to climate change.In order to study runoff response to climate change, this article takes Vakhsh River basin of Tajikistanas the research area, uses the Xinˊanjiang model containing the snowmelt structure to conduct monthlyrunoff process simulation of the research area in1976-1985, and then takes the measured runoff data toanalysis the result of the model. The simulated runoff process can reflect the trend of the actual runoffprocess.This article Select the GARM hydrological station of Vakhsh River Basin from1976to1990measured data to study the runoff response to climate change, the monthly average precipitation,temperature, runoff and evaporation as model input data, and then use has been constructed the Xinˊanjiang model containing the snowmelt structure to simulate the runoff process under different climaticconditions, the simulation plans are: The temperature keeps invariable and the precipitation increases orreduces20percent; the precipitation keeps invariable and the temperature increases1℃or2℃.Simulationresult shows that: when the precipitation reduces20percent, the annual runoff during1976-1990separatelyincreases:-34.89%、-14.98%、-17.44%、-23.01%、-0.88%、0.89%、21.30%、-15.22%、-4.71%、-21.33%、7.46%、3.54%、-22.11%、17.93%、6.25%, the average increases range is-6.48%;When the precipitationincreases20percent, the annual runoff during1976-1990separately increases:-26.22%、-8.04%、-9.86%、-11.96%、7.76%、11.19%、36.05%、-2.02%、36.99%、11.81%、30.46%、26.72%、0.30%、45.70%、41.51%, the average increases range is12.69%.When the temperature increases1℃, the annual runoffduring1976-1990separately increases:-22.35%、-3.12%、-7.61%、-11.55%、10.92%、15.11%、36.04%、-19.77%、1.03%、27.02%、36.69%、20.18%、-6.78%、39.22%、34.74%, the average increases range is9.98%. When the temperature increases2℃, the annual runoff during1976-1990separately increases:-8.71%、2.88%、-2.05%、-3.33%、19.32%、24.48%、20.20%、-33.84%、38.36%、34.94%、43.90%、28.91%、-1.27%、45.07%、38.86%, the average increases range is16.51%.The impact to runoff of Vakhshriver basin is smaller under the precipitation change, annual runoff change is not obvious, the runoff of theVakhsh river basin with temperature change is positive response. We can obtain that the runoff of Vakhshriver basin with temperature change is more obvious than with precipitation change.