Water Resources in the MR

Historically and geographically, the MRB can be divided into two parts: the Upper Mekong Basin (UMB) constituting China and Myanmar (24 per cent of the total catchment area) and the Lower Mekong Basin (LMB) constituting Cambodia, Laos, Thailand, and Viet Nam (76 per cent of the total catchment area). The MRB is home to nearly 75 million people with 90 distinct ethnic groups (Matthews and Geheb 2015). Encompassing a vast range of geographic and climatic zones, the amount of water resources internally renewable annually varies widely by country. Moreover, land and water resources in the region also vary with location and season. For example, although only 16 per cent of the total discharge originates from the UMB, during the critical dry season, China discharges water to most of the Mekong mainstream flow in Laos and Thailand and contributes to almost 45 per cent of the average flow in Cambodia (Goh 2004).

As the longest river in Southeast Asia, the name roughly translating to ‘mother of water’ in the Lao and Thai languages, the Mekong is the region’s largest water resource and provides the largest related resources with power generation potential that support on-going economic development and MRB community livelihoods. Particularly, water use for irrigation is expected to increase in the LMB (FAO 2012). Table 26.2 reports a summary of distributions of water and land resources in the MRB.

Although the MRB is one of the richest areas of biodiversity in the world, the six riparian states have quite different long-term major use patterns of the river. Three primary economic services for the millions who live in the MR are

Table 26.2. Territory of six countries and their contribution to the Mekong’s flow

Note: MRB, Mekong River Basin. Source: Based on MRC (2005).

transportation, renewable freshwater, and electric power (Roland-Holst and Heft-Neal 2012). Water resources are used mainly for hydropower production and irrigation (MRC 2010). Based on the calculated models of four main different sectors ofwater uses in 2010, Houba, Pham Do, and Zhu (2013) show that (i) water use for irrigation generates the highest aggregate economic value for China and the LMB; and (ii) water use for hydropower generation contributes the second highest economic value for China, whereas fishery is the second highest for the LMB.