'TIME FLOOD FORECASTING FOR HYDRAULIC RISK MANAGEMENT: THE LATERAL FLOW REPRESENTATION ISSUE'

Accurate forecast stages at river sections is of paramount importance to properly address Flood Forecasting and Warning Systems (FFWSs) operating in real-time. The forecast values can be provided by flood wave routing models to be implemented when gauged sections are operative along the channel. Different models have been proposed in the literature and the forecast can be approached by neglecting or involving the contribution of lateral flows. Among the latter, STAFOM-RCM (STAge FOrecasting Model-Rating Curve Model) assumes a lateral contribution uniformly distributed along the reach (Barbetta et al., 2011). Therefore, the model application is not suitable for future stage prediction at hydrometric sections just located downstream river confluences. To overcome this issue, we propose a methodology that exploits the forecast stage provided by STAFOM-RCM at a gauged site on the tributary and the relationship between the stages recorded here and the ones at the downstream site along the main channel. The Paglia River basin, in central Italy, is selected as case study. The results indicate that the procedure can be useful to address real-time hydraulic risk management even at river sections located downstream important confluences, provided that gauged sites are operative along the tributary