澜沧江-湄公河流域水库联合调度防洪作用

Potential role of coordinated operation of transboundary multi-reservoir system to reduce flood risk in the Lancang-Mekong River basin

  • 摘要: 澜沧江-湄公河流域汛期洪灾频发,气候变化极有可能进一步加剧该区域洪水的量级和发生频率,需要上下游合作共同应对。建立了澜沧江-湄公河全流域分布式水文及水库调度模型,模拟1991-2005年全流域13条支流和5个干流防洪控制断面的逐日天然流量过程,在此基础上模拟全流域已建、在建和规划水库的联合调度过程,分析防洪作用。结果表明:①全流域水库联合调度对湄公河5个主要断面均有显著的防洪作用,在完全按照防洪目标对水库进行调度的情况下可将200年一遇洪水减至20~50年一遇。②湄公河左岸支流的防洪能力远高于右岸,具有较高防洪能力的支流有澜沧江、南乌河、南俄河、南屯河、濛河、色公河和桑河。③对不同断面起主要防洪作用的支流不同:在琅勃拉邦上游,澜沧江、南乌河起主要作用;在那空帕农断面,南俄河与南屯河加总的防洪作用与澜沧江基本相等;在巴色下游,濛河和色公河的作用均超过澜沧江。澜湄合作机制为上下游防洪合作提供了重要契机,研究成果可为流域国协商建立联合防洪调度机制提供参考。

     

    Abstract: The Lancang-Mekong River (LMR) basin has historically been affected by severe floods and is likely to suffer further flood events with higher peaks and longer duration in the future due to climate change, which calls for collective action to respond. This study examined the potential flood control effect of coordinated operation of the LMR transboundary multi-reservoir system by establishing a distributed hydrological model coupled with a reservoir operating model, simulating the runoff of 13 tributaries and 5 mainstream sections. Results show that:① Flood magnitude at the five sections along the Mekong River is significantly reduced by mitigating flood recurrence from 200 years to 20-50 years.② In terms of flood control, the left-bank tributaries contribute more than the right bank. Tributaries with relatively higher flood control capacity are:Lancang, Nam Ou, Nam Ngum and Nam Theun, Nam Mun, Se Kong and Se San. ③ Different tributaries play a major role in flood control across regions. Luang Prabang's main flood control tributaries are Lancang and Nam Ou. At Nakhon Phanom, Lancang's flood control contribution is same as Nam Ngum and Nam Theun's sum. In the downstream of Pakse, the flood control contribution of Nam Mun and Se Kong are higher than Lancang. This research provides a reference for transboundary flood control cooperation between riparian countries, which face an important opportunity underpinned by the Lancang-Mekong Cooperation Mechanism (LMC).

     

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