大壩風潮下湄公河流域的水域治理難題：以越南為例

Difficulties in Water Governance in the Mekong River Basin under the Dam Surge: A Case Study of Vietnam

二十多年來，湄公河中上游的水電大壩開發，形成一股大壩風潮，這明顯地改變了下游水文條件及特性。其可能引起的各種後果，除了包括傳統的軍事安全之外，另外也造成湄公河流域利害關係國的各種環境與經濟等非傳統安全上的疑慮。由於中上游大壩的快速發展，湄公河流域的國家就籠罩相似的社會、經濟、環境等等問題。特別是處於下游的國家，需要以區域合作的方式來加以應對。本文以湄公河下游的越南為例，討論越南目前面對的難題。因為水壩大都建造在上游的河流谷地，所以從上游以降皆造成各種不同影響。建造大壩代表著會有一定面積的土地被淹沒，並導致不少村莊的遷徙，以及居民的重新安置；同時也使得下游的國家對於河流資源的合理使用、水源的減少產生憂慮，內心縈繞著資源被剝奪的焦慮感。本文在各類研究報告及親身實地訪查湄公河的基礎上，發現越南面對的各項水域治理難題，主要有大壩建設後的水源減少、下游乾旱，泥沙減少造成的河岸侵蝕，地下水位降低引起的土壤鹽化。而越南所採取的對應策略則為善用運河灌溉系統、普及自來水、嚴管河沙開採與保留洪氾平原，法規中加入應對氣候變化和可持續發展的新目標，並利用區域組織、資訊平台、主動協調等，強化區域合作。

This article takes Vietnam in the lower Mekong River as an example to discuss the difficulties that Vietnam is currently facing. Because dams are mostly built in upstream river valleys, there are various impacts from upstream and downstream. The construction of the dam means that a certain area of land will be submerged, which will lead to the relocation of many villages and the resettlement of residents; at the same time, it also makes the downstream countries which are full of anxiety about being deprived of resources worry about the rational use of river resources and the reduction of water sources. Based on various research reports and field visits to the Mekong River, this article finds out that Vietnam faces various water governance difficulties, mainly including the reduction of water sources after the construction of the dam, the downstream drought, the erosion of riverbanks caused by the reduction of sediment, and the salinization of soil caused by the reduction of the groundwater level. The corresponding strategies adopted by Vietnam are to make good use of canal irrigation systems, popularize running water, strictly control river sand mining and preserve floodplains, add new goals to address climate change and sustainable development in regulations, and use regional organizations, information platforms, active coordination, etc., to strengthen regional cooperation.