Effects of land-use changes on the hydrologic response of reclamation systems

Our study investigates the possible effects of recent land-use changes on the frequency regime of floods for reclaimed lands. We modelled the runoff concentration behaviour of a reclaimed area of 76 km2, located in the Po River plain near the city of Bologna (northern Italy), through the combined application of a semi-distributed rainfall-runoff model, which captures the key features of surface and sub-surface flows, and a hydrodynamic streamflow routing model. Three land use data from 1955, 1980 and 1992 were available. We implemented the rainfall-runoff model to the three land-use scenarios and analysed the hydrological-hydraulic behaviour of the study area for numerous rainfall events associated with different recurrence interval. The results of our study show a rather significant sensitivity of the flood frequency regime of the reclaimed land to land-use changes, and the sensitivity tends to increase as the recurrence interval of the rainfall event decreases.