Implementation of reservoirs in hydrological calculations with Iber

Accounting for the flood routing effect of reservoirs in the assessment of flood discharges is essential in basins where the hydrology is conditioned by the presence of one or more dams. This paper presents the implementation of reservoirs and dams in the hydrological module of the software Iber, which solves the two-dimensional shallow water equations at the scale of an entire basin. Spillways with and without gates, low level outlets, and the possibility to define an ad hoc outflow curve relating the flow rate to the reservoir level are included. As a case study, the effect of the Iznajar reservoir on the hydrology of the Genil basin in Spain was modelled. Three scenarios were considered to compare the effect of the different outflow structures included in this new implementation in Iber. The defined methodology proves to be able to represent numerically the outflow structures, addressing a fundamental limitation in the modelling of large basins with Iber.