The water primrose, Ludwigia peploides, is one non-native invasive aquatic plant in the Mediterranean part of South-East of France. It can colonise many types of static or slow-flowing waters: rivers, shallow ponds and lakes, wetlands, etc. Their biomass abundance and monospecific stands leads to local loss of floral and faunal biodiversity. It colonised many biotopes in the Vistre River, a 46 km long river highly impacted by strong hydraulic modifications, close to the urban area of Nîmes (Gard). Their impact on native hydrophytes ( for example Myriophyllum spicatum) is significant in some sites. A new watershed management plan was built in 2001 by the managers from the "Syndicat Mixte du Bassin Versant du Vistre" for increasing the ecological functioning of the river. Among the management operations, the reduction of the colonization of L. peploides was undertaken since 2008 by mechanical and manual removal. In 2008, the length of management was about 5 000 m and the volume of removed plants was 173 m3 of wet plants, with about 100 m3 of mechanical removal, for 75 work days. In 2009, the length increased to about 14 000 m in other parts of the river and its affluents with 152 m3 of manual removed plants for 85 work days. Several sites managed in 2008 shows little yearly colonization. A long term management of this plant is necessary to minimize all impacts of L. peploides and insure better ecological functioning of the river in the context of the Water Framework Directive.