the great mekong in laos

laos khong champasak district boats bank great mekong river trans-boundary east asia southeast world39aph39s twelfth-longest third-longest asia1 estimated length 909 050 mi1 drainage area 795 000 km2 307 discharging 475 km3 114 water annually headwaters tibetan plateau runs southwest china lancang myanmar thailand cambodia southern vietnam extreme seasonal variations flow rapids waterfalls navigation major trade route tibet construction hydroelectric dams ecosystem exacerbation drought