Flow characterization temporary streams : using the model SIMGRO for the Evrotas basin, Greece

Tools were developed to quantify space–time development of different flow phases on a river basin scale. Such information is needed for the WFD. The spatial development of temporary streams was investigated in the Evrotas basin, Greece. We used the regional hydrological model SIMGRO in a GIS framework to generate flow time series for all major streams. For a streams reach five flow phases are distinguished, being: floods; riffles; connected flow; pools and dry conditions. For each stream and flow phase, thresholds were identified based on local characteristics. The analysis shows the frequency of the flow phases per month. For all streams in the Evrotas basin the average frequency of the flow phase dry and pools are presented. The aim is that GIS helps to better understand the link between dry streams and spatially-distributed catchment characteristics. Local morphological conditions and roughness of the bed need to be considered in defining appropriate threshold levels for the flow phases.