This paper attempts an explanation for the persistence of Khmer cultural identifications on the Ca Mau Peninsula of Vietnam. This low-lying peninsula is a unique human environment, where Khmer villages, Buddhist temple festivals and livelihood activities are centred on a network of saline-infested rivers. The presence of Khmer communities along these waterways is noteworthy, for much scholarship suggests that the waterways of the multi-ethnic lower Mekong region tend to be dominated by non-Khmer ethnic groups. The vigorous Khmer presence on the peninsula is even more intriguing given that the peninsula is a migratory and trade oriented region, long under Vietnamese administration and subject to military and environmental upheavals that have challenged Khmer tenure.

The paper suggests that mastery of communal water harvesting allowed Khmers to survive the long saline water season and gave them a secure foothold in this region. Additionally, their collaborative water harvesting practices contributed to cohesion and a common identity among Khmers and helped strengthen the Theravada Buddhist wat as one of the key cultural institutions on the peninsula. However, the development of an extensive irrigation network by the Vietnamese state in the last thirty years has had the opposite effect. Canal developments facilitated intensive agriculture, immigration and the introduction of new cultural models into the peninsula, while creating economic and environmental insecurity for Khmers and undercutting the traditional grounds for collaboration. Such changes cast light on the links between ethnic identifications and the system of fresh water provision in the lower Mekong region.