ABSTRACT
The Mekong river is located in the sub-tropical and tropical regions of SouthEast Asia; its riparians are China, Burma (Myanmar), Thailand, Laos, Vietnam and Cambodia. The Mekong catchment covers 810,000 sq km and drains into the South China Sea from the deltaic plains of Cambodia and Vietnam. Being a river with a naturally high variation in flow discharges and many rapids, as well as the Khone waterfalls, it has never been fully navigable. Development indices for the basin states show a wide variety, with Thailand by far leading the per capita income statistics and the two downstream states Cambodia and Vietnam having annual incomes at a level 10 times inferior to Thailand. The basin can be divided into an upper and a lower catchment according to
different criteria: geologic, hydrologic or socio-economic. From its source in the Tibetan mountains at over 5,000 m above sea level, the river’s main branch descends to an elevation of approximately 500 m above sea level in the Lao People’s Democratic Republic (Lao PDR), marking the steeper part of the catchment with gorges and numerous rapids. In contrast to this, the deltaic regions of Cambodia and Vietnam are characterized by vast and flat floodplains made up of the alluvial loads that the river delivers every year. The extreme seasonality of water levels adds to the unique hydrologic
characteristics of the lower basin: during the wet season large areas of the plains in Cambodia and Vietnam are inundated and traditionally cultivated with so-called flood rice varieties adapted to fluctuations in the water level. For Vietnam’s coastal plains, sea water intrusion during the dry season in combination with the natural drainage of acid sulphate soils constitutes a unique case of land and water interactions. In the dry season, sea water intrudes from the South China Sea into the delta’s estuaries, posing immense problems (of salt water intrusion) for rice production. After the intensive construction of canals and dikes in recent decades, much of the area is separated from the seasonal floods, being highly productive through the cultivation of three crops per year. The basin is also home to a large variety of aquatic species, on which the delta’s people rely heavily for protein supply; these fish and other aquatic species are adapted to the varying river levels and salt seasonality (in the lower reaches). The freshwater lake of Tonle Sap is considered the world’s most productive inland fishery; in Vietnam aquaculture already plays a significant role. Increasing population pressure both in terms of settlement area and land
productivity has resulted in the construction of sluices to keep sea water from
flowing upstream along several deltaic estuaries in Vietnam. However, this intervention in the natural hydrologic regime is criticized by environmental NGOs and fisher folk as it also interferes in the brackish water cycle vital for the lower delta’s aquatic species. In the river basin literature, the Mekong is characterized as one of the last
large river systems of the world that remains largely undeveloped in terms of dams and regulation structures along its main branch that would alter the natural flow regime. The basin’s riparian interests and objectives concerning water resource
development are as different as the combination of geo-hydrology with the livelihood patterns present in the traditional riparian people’s communities. In the upstream area, China’s foremost interest is the development of hydropower dams to provide continuous and comparatively cheap energy for its vibrant east coast; during the last decades, three big dam projects have been realized on Chinese territory, with more in the planning or construction stage, which will result in a cascade of eight hydropower dams. The further the Mekong advances towards its mouth, the more important traditional fishing practices become for the protein intake and livelihoods of the people living on its banks. This fact is only partially acknowledged by the ruling powers of the riparian states, as in the example of Lao PDR. Although, for the whole country, the construction of hydropower infrastructure and its impact on development both in the country and in the region (through sharing energy by means of a regional power grid) are important objectives of Mekong basin management, the fishing communities along the river see unimpeded flows and sustained seasonality as important. Thailand is another important country because it is economically successful, and as an influential actor in the basin it has different interests from downstream riparians. As the potential for irrigation system development is comparatively small (on account of former infrastructure developments in the country) and as the more developed tertiary sector is energy hungry, Thailand’s focus in respect of basin development lies increasingly on hydropower generation. Cambodia is situated in the northern part of the Mekong’s deltaic estuaries.
A special hydrologic feature of the landscape is the Tonle Sap lake. Its coastline contracts and expands dramatically with the varying discharge of the Mekong, acting like a buffer: during the wet season, water flows into the lake and revitalizes the biologic cycle of the aquatic ecosystem, whereas during the dry season the lake drains into the lower lying southern delta area of Vietnam. As in the latter country, people living in the area have adapted their lifestyles and economic activities (fishing, wet season flood rice cropping) to the hydrologic variations. Both countries are also frequently affected by high floods that cause damage to settlements and infrastructure. Satisfying all the different interests of riparian communities and countries
(interests that are not necessarily the same even on the national scale) proves difficult in multi-stakeholder negotiations on the basin scale. The present organization responsible for basin-wide co-ordination is the Mekong River
Commission (MBC), joined by Lao PDR, Thailand, Cambodia and Vietnam; Burma (Myanmar) and China did not join the platform formally. The MBC is the follow-up organization resulting from international efforts to achieve basin-wide concerted water management and has its legal foundations in a 1995 draft agreement initiated by the UN Development Programme (UNDP) and other international organizations. However, the fact that the two upstream riparian states have only observatory status and are not willing to make concessions during multipartite negotiations makes any comprehensive basin management impossible. Thus, the river basin organization has only limited responsibility and deals mainly with information gathering, exchange and related forecasting activities, and the formulation of development objectives for the downstream riparians. These objectives include freedom of navigation, the maintenance of the dry season flow regime and its pulses feeding and emptying lake Tonle Sap, and the improvement of the situation of acid sulphate soils and their adverse effects on surrounding ecosystems and people’s livelihoods. Further integration of the two upstream riparians in co-operative efforts is envisaged by some writers who point to the influential position of the Association of Southeast Asian Nations (ASEAN, with regional integration as the stated objective)—which has a broader focus than ‘just’ on water and thus provides an enabling environment-and the Greater Mekong Subregion (GMS) programme initiated by the World Bank, the Asian Development Bank and the UNDP. However, whether the comparatively weak economic and political influence of downstream riparians in these fora can play an important role in achieving (or rather safeguarding) their interests is a matter of conjecture.
