Seasonal flooding is a feature of traditional Cambodian life. For thousands of years the rising waters of the Mekong river have brought rich silt that replenished farmland, water to irrigate rice paddies, and an abundance of fish. In a few weeks Cambodia will celebrate Water Festival, the regional holiday that celebrates the high waters of the rainy season including the miracle of the Tonle Sap reversing flow.

But recently the seasonal flooding here in Cambodia hasn’t followed it’s traditional course. Hydroelectric dams, sand dredging, deforestation, and lake/swamp filling in on a massive scale have shifted the flow of the river. The Mekong current was once slowed by sand dunes, with overflow absorbed before being slowly released by lakes/swamps/forests, and channeled to predictable floodplains that were covered with rice paddies. Now the river flows more swiftly, rushing past traditional floodplains only to flood into new areas including cities and towns that were not built with flooding in mind. Traditional houses in floodplains are elevated, built on silts, but ‘modern’ housing units are not.

You might remember that, last year, a group of us helped pull a car out of the floods. The area where that family lives has flooded again this year. This area was once considered safe from floods but it looks like it is now a new seasonal floodplain. The people who live there were watching for flooding this year and prepared – but their homes and local infrastructure were not built with this kind of flooding in mind. One example of this was the Ministry of Water Resources breaking a hole in a dike that had become a dam, holding in flood waters instead of keeping it out. The dike was designed with the assumption that the seasonal flood waters would flow as they always have but the Mekong river has changed.

Climate change further exasperates this environmental destabilization. The same amount of seasonal rainfall is occurring but instead of the reliable monsoon rains of the past the rains are coming in shorter more intense bursts resulting in flash floods and interspersed with longer periods with no rain.