The Planning System and Flood Risk Management - Offaly County ...

3.1 Flood RiskUnderstanding the nature and extent of flood risk is an essential starting pointin achieving an effective design response to flood risk on a typical site. FigureB1 below illustrates the type of flood mapping, showing flood zones, that isnecessary as a starting point to the design process.Fig. B1: Flood Zone Risk MappingThe figure above indicates Zone A as the extent of the site area that has thehighest probability of flooding, Zone B has a moderate risk of flooding andZone C has a low risk of flooding.3.2 Choosing land usesOnce the spatial dimension of flood risk is understood, land use type andlocation are informed by the following principal considerations:• The most vulnerable land uses are located in areas of lower flood risk;• Less vulnerable land uses (e.g. parks, gardens and open spaces fornatural habitats, etc.) are located in areas of higher flood risk;• A degree of flexibility in the location of land uses to better reflect existing,or future, good urban structure;• Providing more sustainable mix use by, for example, considering lessvulnerable uses at ground floor in areas of greater flood risk.73Planning Guidelines