ACLNInternational audienceThis article assimilates the city of Phnom Penh to an open system that has spread into the Mekong River floodplain by backfilling tidelands and building successive dikes. The city's hydraulic networks were damaged by the major crisis suffered under the Khmer Rouge characterized by a strong de-urbanization process. Since 1979, the progressive restoration of institutions in addition to ad hoc interventions led by "pioneer actors" on the city's networks allowed vertical interactions in the city-system between stakeholders and structures to redevelop as well as permitting horizontal interactions between structures. Despite newer crises, the city-system proves to be resilient and maintains its dualistic kernel/margins s...