Evaluation of a new 18-year MODIS-derived surface water fraction dataset for constructing Mediterranean wetland open surface water dynamics

•We constructed 8-day water extent time series (2000–2017) for 340 wetlands with MODIS.•Validation was performed with a Landsat dataset and water level data.•Allows monitoring the dynamics of small wetlands (<1 km2) with high varibility.•Provides a useful tool for capturing abnormal changes and short-duration events.