对西藏“一江两河”河谷地区风沙灾害的一些粗浅认识和治理工作建议

A Updated Understanding of Wind-Sand Disaster in the Valley Area of“One River and Two Tributaries”in Tibet of China and Suggestions for Control Work

西藏“一江两河”河谷地带风沙地貌发育,风沙灾害严重。由于扎囊黄土古土壤剖面中无风沙夹层并结合考古研究成果,作者认为该地区的风沙灾害可能始于以青稞农耕为代表的历史时期以来的大规模开发,并随着人类开发强度的加大,风沙灾害日趋严重。近年来,西藏生态工程建设成效显著,风沙危害有所减轻,但由于冬春季节大面积河床和沙滩裸露以及缺水严重的高台沙地和沙坡地难以绿化,风沙危害依然相当严重。针对该区风沙灾害的治理难点,作者提出了“营造冬春河道人工湿地,抑制干季裸露河床和沙滩的起沙”和“埋铺阻蓄水土层,改善土壤水分条件,绿化沙地”两项治理措施建议。

The“one river and two tributaries”(refers to the Yarlung Zangbo River and its two longest tributaries,the Lhase River and the Nianchu River)valley area in Tibet has well developed aeolian landforms,and there the wind-sand disasters are serious.Because of the absence of aeolian sand interlayers in the Zanang loess paleosol profiles and combined with archaeological research results,the author believes that the wind-sand disasters in this area may have started from large-scale development since the ancient period represented by highland barley farming,and followed by the wind-sand disasters getting worse with the increase in development intensity.In recent years,remarkable achievements have been made in the ecological engineering construction in Tibet,and the hazards of sandstorms have been alleviated to some extent.However,due to the large area of exposed riverbed and sandy beach in winter and spring,and the difficulty in greening high-terrace sandy land and sandy slope land with serious water shortage,the hazards of sandstorms are still quite serious.In response to the difficulties in the management of wind-sand disasters in this area,the author proposes to“build artificial wetlands in winter and spring river courses to restrain sand motivation from exposed riverbeds and beaches in dry seasons”and to“pave selected water-bearing aquifers to improve soil moisture conditions for afforestation”,both of two governance measures quite promising.