An inventory was established for adult water beetles on 7 sites of 4 cut-off lateral channels in the upper Rhône floodplain near Belley (Ain, Savoie), in 2004 and 2005. Overall, 89 species were collected, accounting for up to 75 % of the species known to that region. Laccobius albipes, Haliplus mucronatus, H. fulvus, Bidessus delicatulus, Laccobius sinuatus, Ochthebius crenulatus and Agabus brunneus were among the rarest species on a regional scale. Sampling sites contained between 12 and 63 species. The pond-like (disconnected) appearance, the good quality of the ground water, the surrounding rather natural landscape, the presence of well vegetated gently-sloping margins and the very low densities of fishes were positive factors. The effect of the restoration measures was evaluated on one site which was completely refreshed during the winter of 2004–2005. The following spring, the community was found to be severely reduced but then recovered very quickly. This could be explained by the high mobility of these insects and the presence of reservoir-populations nearby. Sites along the channels with steep margins contained few species. Restoration measures should include, besides the re-digging of continuous, flowing lateral channels, the digging of series of isolated, permanent or temporary ponds.