Mekong River water: will river flows meet future agriculture needs in the Lower Mekong Basin?

摘要

More than 41% of the land area of the Lower Mekong Basin (LMB) is used for agricultural production and the area under cultivation is steadily expanding to produce more food for the burgeoning populations of Laos, Thailand, Cambodia and Viet Nam. Agriculture is also responsible for 80-90% of water abstractions from the Mekong River, most of which is for crop cultivation with smaller amounts being consumed by the increasing number of fish/shrimp farms and animals. Limited access to water is a major constraint to increasing crop production in the LMB and irrigation schemes continue to be installed or improved in each of the four countries. The Mekong Delta in Viet Nam already faces water availability problems and seawater incursions during the critical months of February-May. This situation will be exacerbated even further as upstream abstractions increase. Fertile soils and a high level of renewable water resources indicate the potential for irrigation development is high in Laos and to a lesser extent in Cambodia. Use of existing schemes in North-east Thailand may also increase. New farming systems proposed by the Vietnamese Government for each of the ecological zones in the Mekong Delta may reduce the amount of water consumed by rice but increase the level of abstractions for upland crops, perennials and fish/ shrimp ponds during the critical period. Each country, therefore, needs to carefully plan its current water consumption regimes. Negotiations are currently underway between the four LMB countries to ensure an equitable distribution for future development.