Estimation of stream-aquifer exchanges at regional scale using a distributed model: Sensitivity to in-stream water level fluctuations, riverbed elevation and roughness

•Stream-aquifer exchanges are quantified at regional scale with a 1km-resolution.•River stage fluctuations strongly impact stream-aquifer exchanges.•River stage time variability can induce flow reversals of stream-aquifer exchanges.•Errors on river morphological features impact stream-aquifer exchanges estimations.