Tonle Sap

Among most productive inland waters of the world

     The Mekong River is one of the world’s largest rivers at more than 4,600 km long and a watershed of nearly 800,000 km2. The Tonle Sap Lake in Cambodia is connected to the Mekong River via the Tonle Sap River, and in the dry, low-water season, water flows out of the lake into the river. With a rising Mekong River driven by monsoon rains, the Tonle Sap River flow reverses and delivers water and sediments to the lake. During this time the Tonle Sap Lake increases in area from approximately 2,500 km2 to over 10,000 km2. The Tonle Sap Lake is believed to be one of the most productive inland waters in the world because of its unique “flood-pulse” hydrologic regime and the strong connections between the lake and surrounding floodplain. The specific mechanisms at play which support fisheries and biodiversity are currently unknown, yet this information is critically important when considering policy to maintain ecosystem goods and services.