Define Areal Flood Warning

Flooding is a recurring problem that affects many urban areas worldwide, causing significant damage and disruption to daily life. In recent years, the frequency and severity of flood events have increased due to climate change and urbanization. As a result, effective flood warning systems are essential for mitigating the impact of flooding. One such system is the rainfall threshold-based flood early warning system (FEWS), which has gained popularity in recent years.

Areal flood warnings are an essential component of FEWS, providing critical information to residents, emergency responders, and urban planners about potential flood events. In this context, a polder area is a low-lying region surrounded by embankments, often located in deltas near rivers or coastal areas. Polders rely heavily on pumping systems to remove water from inner rivers (artificial rivers inside the polder area) to outer rivers, especially during storms.

In designing a rainfall threshold-based flood early warning system for a polder area, it is essential to evaluate its benefits and trade-offs. Recent studies have shown that probabilistic forecasts of rainfall can significantly enhance the metrics that represent waterlogging and pumping costs. These forecasts are represented using the concept of 'predictive uncertainty' (PU), which provides valuable insights into the likelihood and potential impact of flood events.

To assess the effectiveness of areal flood warnings, it is crucial to compare the values of various metrics across different scenarios. These scenarios may include no warning, perfect deterministic, probabilistic forecast, and other possible scenarios. The framework used in this study computes metrics that give the potential waterlogging duration, maximum inundated area, and pump operation costs by considering the full range of potential storms.

In conclusion, areal flood warnings are a critical component of rainfall threshold-based flood early warning systems for polder areas. By evaluating the benefits and trade-offs of these systems, urban planners and emergency responders can develop effective strategies to mitigate the impact of flooding in urban areas. The use of probabilistic forecasts and predictive uncertainty can significantly enhance the accuracy and effectiveness of areal flood warnings, ultimately saving lives and reducing damage caused by flooding.

Define areal flood warning