Tonle Sap Lake and River and confluence with the Mekong River in Cambodia

Abstract

F or centuries the floating villages on Tonle Sap Lake, Cambodia (figure 1), have derived their livelihoods from the fish and water resources of the lake and its expanding and contracting floodplains. Historically, the lake enabled the powerful Khmer civilization near Siem Reap (figure 2) to develop an elaborate hydraulic complex to irrigate rice ( Oryza sativa ) fields and support one of the largest premodern urban populations in the world (Goscha 2016). Today the rice-fish diet continues to be the staple of rural and urban daily meals throughout Southeast Asia. The Tonle Sap River flows 147 km (91 mi) southeast from Tonle Sap Lake to meet during the dry season with the Mekong River near Phnom Penh, the capital of Cambodia. In the monsoon season (May to October), the Mekong River floods and causes the water to back up into the Tonle Sap River, reversing its flow (Carling 2009). This wet season flow reversal brings Mekong River sediments, nutrients, and an abundance of fish into the lake and enlarges the lake into its floodplain 20 to 40 km (12 to 25 mi). Farmers and fishers of Cambodia have developed cultural and economic practices based on the Mekong River's dependable dry and wet…