Coastal cities combine intensive socioeconomic activities and investments with high exposure to flood hazards. Developing effective strategies to manage flood risk in coastal cities is often a costly and complicated process. In designing strategies, engineers rely on computationally demanding flood simulation models, but they can only compare a limited number of strategies due to computational constraints. This limits the efficacy of standard flood simulation models in the crucial conceptual phase of flood risk management. This paper presents the Flood Risk Reduction Evaluation and Screening (FLORES) model, which provides useful risk information in this early conceptual phase. FLORES rapidly performs numerous simulations and compares the impact of many storms, strategies, and future scenarios. This article presents FLORES and demonstrates its merits in a case study for Beira, Mozambique. Our results demonstrate that expansion of the drainage capacity and strengthening of its coastal protection in the southwest are crucial components of any effective flood risk management strategy for Beira.

Overstromingen als gevolg van orkaan Ike in september 2008 veroorzaakten grote schade rondom Galveston Bay en Houston, Texas. Masterstudent Robert de Boer (TU Delft) bestudeerde voor zijn afstuderen het wereldwijd populaire concept ‘Building with Nature’ (BwN). Voor Galveston Bay is een methode ontwikkeld om de natuurwaarde en bijdrage aan waterveiligheid van het BwN-concept inzichtelijk te maken. Aansluitend is een ontwerp gemaakt met BwN-elementen. Om het overstromingsrisico in Galveston Bay significant te reduceren, zouden BwN-maatregelen met ‘harde’ bescherming kunnen worden gecombineerd.