MERLIN: a flood hazard forecasting system for coastal river reaches

This study presents MERLIN, an innovative flood hazard forecasting system for predicting discharges and water levels at flood prone areas of coastal catchments. Discharge forecasts are preceded by a hindcast stage. During this stage, the hydrological models assimilate soil moisture and hydro-meteorological observations to evaluate soil infiltration capacities at the beginning of the discharge forecast. Predicted discharges are converted to water-level forecasts using the hydraulic model Iber+, a GPU-parallelized bidimensional flow model. Hydraulic models also assimilate tidal-level forecasts in order to define the boundary conditions of the models. The performance of MERLIN was evaluated over 4 months at three coastal catchments of 4.95, 16.96, and 83.9 km2. Forecasted discharges and water levels presented a good fit to observed values, especially at the larger catchments, which confirmed the potential utility of the presented system.