Source: Molyvann, Vann. Modern Khmer Cities. Phnom Penh, Cambodia : Reyum ; [Chicago, IL?] : Sales and distribution, USA, Art Media Resources, c2003.
“It is a system of Prek which manage the annual cycle of flooding in order to make the rise in water productive. The prek is a canal in which water runs into the fields during times of flooding and then out toward the river at the beginning of the dry season. Most prek are man-made, having been dug by local inhabitants in order to allow flood waters to fill low-lying fields located behind the natural embankments of the river banks. The bottom of the prek is at a height somewhat higher than the lowest water level of the river. The first flood wateres therefore do not enter the prek. It is only the later silt laden waters of the floods which are allowed to enter the prek, flooding the interior fields and depositing new silt each year on the low-lying fields behind the riverbank. The which receives these alluvial deposits is considered the most fertile of the country. After the flood waters recede, some of the water is stored in bengs, or ponds, found in the low-lying fields behind the riverbanks. As the dry season proceeds, these beng often dry up completely only to once again become large lakes as the annual rains and flood waters come. The work of the prek is necessarily undertaken collectively through collaborative labor organized by elders and notables of the villages who divide the fields according to the amount of labor each villager has contributed. This communal system of managing water resources has, over millenium, shaped the morphology of the banks of the Mekong River.”