Mekong exhibits in cambodia

The lower Mekong exhibits pronounced seasonal variations in flow, reflecting rainfall patterns~ Water levels are lowest in April and May; at this time, many water bodies in the inundation zone are isolated, and the smaller tributaries tend to dry out. With the onset of the monsoon rains in late May, almost the entire region is transformed into a sheet of muddy water. Rivers, tributaries and numerous small ponds, oxbows and ditches are engulfed. The river starts to rise shortly after the onset of the monsoon, and attains its maximum level in September or October. It then falls rapidly until December and slowly thereafter to reach its lowest level in April. Extensive flooding takes place on both banks, but the by-pass flow on the western bank escapes towards the Great Lake (site 2). The main channel also adds its flow to the waters of the Great Lake through the Tonle Sap River which reverses direction during the rising flood. The Great Lake thus acts as a natural flood retention basin, without which the delta would be flooded to even greater depths. Towards the end of the rainy season in September and October, some seven million ha of lowlands in the delta and around the Great Lake are covered with water at various depths of flooding.