Hydrologic Response to Land Use Change in the Kifisos Experimental Sub-Basin, Athens, Greece

This study investigated the impact of land use change on mean annual discharge in an experimental sub-basin in the metropolitan area of Athens, Greece, using the Soil and Water Assessment Tool (SWAT) model. The study site, the NW sub-basin of the Kifisos river basin, experienced an increase in artificial surfaces from 42.1 km2 in 1990 to 71.6 km2 in 2018. Therefore, the selected study site is an excellent case study to quantify the impact of urbanization on water balance components. The simulated discharge was compared to four land use scenarios (i.e. land use maps: 1990, 2000, 2006, and 2012) under the same climate conditions. Results showed that from 1990 to 2018: (i) the expansion of urban areas led to an increase of discharge by 8.7%, as water yield increased and evapotranspiration decreased, (ii) under the same climate conditions, runoff changes were observed during the late dry season, and (iii) the impact of land use change was more noticeable in the suburban sub-basins with significant urbanization. Overall, the outcomes of this study provide essential knowledge of the hydrological processes of an urban/peri-urban system which will be useful for planning future development strategies in the region.