山区河流水灾害问题及应对

Big natural disasters worldwide are deeply affecting survival and development of humankind. How to effectively deal with various types of natural disasters is particularly important. After the 2008 Wenchuan earthquake, public awareness about disasters in China has increased considerably and people's understanding of disasters has been greatly improved. That "People on the Earth must have disaster awareness and disaster education" has already become the common sense. Owing to its particular regional geological structure, topographic conditions, hydro-meteorology and other factors, the Western China is a region with frequent water-related disasters. Prevention of and reduction in water disasters have been important for overall development of the region and the country. As a high-level research national university in West China, building on the wisdom of water management of the historical Dujiangyan project, Sichuan University has made many innovations. Through engineering and research projects, such as flood discharge and flood control of high dams, structural safety of high dam projects, prevention of mountain torrents,sediment disasters,and landslides, and ecological environmental protection in river basins, Sichuan University has made a series of important achievements. They include:1) development of meso-scale experiments and simulation techniques to reveal the meso-mechanism of complex water flow phenomena of high dam hydraulics, to establish more reliable criteria and calculation methods, to form a systematic meso-mechanical system, and to innovatively propose multi-level flood discharge mechanism and techniques; 2) new technology of geomechanical model destruction simulation and comprehensive test, which can reveal the overall structural safety response mechanism of high dam engineering, and establishment of a high dam-foundation-reservoir safety evaluation system capable of accurately reflecting the influence of complex geological environments and excessive floods; 3) revealing the "little water with big disaster" mechanism under joint action of mountain floods and sedimentation, and development of the "reduction of scale control and prevention" technology for extreme flood and sediment disasters that can make the uncertainty of the disasters caused by floods and sediments to a preventable scale; 4) introduction of new equipment and technologies such as the three-dimensional laser scanners for landslide deformation monitoring and expansion from "points, lines, and surfaces" to three-dimensional space as a whole, which improves the level of disaster monitoring and early warning of water-powered landslides and disaster emergency response capabilities; 5) a categorized emergency and comprehensive treatment technology for landslide-barrier lakes suitable to various material composition and structural characteristics of landslides and dams; 6) a complete set of methods for ecological water requirement allocation and prediction of water temperature for fish and cascade reservoirs, low-temperature water control, and prediction and regulation of over-saturated total dissolved gas of high dams aiming at characteristics of geography, ecology and environment in southwest region, which has expanded research on ecological and environmental protection from the local engineering and single water environment areas to the overall system of mountain river basins and formed an integrated scientific and technological system that intersects multiple disciplines. At last, aiming at characteristics of water disasters in mountainous rivers in Western China and the general needs for national disaster prevention, mitigation and relief, this paper proposes a series of scientific and technological questions for future research, which will facilitate development of research work in related disciplines for disaster prevention and reduction in the future. The issues include impacts of global climate change on water disasters, coupled disaster environments and regional evolution laws, dynamic processes and catastrophes of water disasters, habitat-biological interaction mechanisms of mutant rivers, ecological evolution mechanism of catastrophic rivers, water disaster risk theory, water disaster monitoring and early warning, collaborative management of water and disaster basins, basic large databases and cloud platforms, and others.