The diagrams presented illustrate two distinct approaches to safeguarding houses in flood-prone regions, one involving the implementation of a stopbank and the other devoid of such a feature.
In summary, the presence of a stopbank significantly alters the flood management strategy, enabling enhanced protective measures against potential inundation.
In the first diagram, which depicts a flood management system incorporating a stopbank, several key components are illustrated. The stopbank itself serves as a barrier designed to hold back floodwaters, ensuring that they do not inundate the internal areas of the property. Adjacent to the river or drain, a floodgate is installed, facilitating controlled water flow. The internal ponding area further assists in managing excess water, allowing it to accumulate without affecting the structural safety of buildings. Notably, the 100-year flood level is marked, with a freeboard of 300 mm above this level to provide an additional safety buffer, contributing to the overall resilience of structures against flooding.
Conversely, the second diagram presents a scenario in which no stopbank is utilized. In this system, the 100-year flood level is designated at a height that poses a significant risk to properties. To mitigate this threat, buildings are raised above the ground level, with the house floor level elevated to provide a safeguard against potential water intrusion. Despite these precautions, the absence of a stopbank diminishes the overall protective capabilities of the structural design, as floodwaters may still reach critical levels without adequate barriers.