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

3.3 The sequential approach for taking account of flood risk is detailed in section3.4 below and a “Justification Test” for the exceptional cases, is detailed insection 3.9.19Photo 4: Limerick, indicating the relationship between the City andthe River Shannon and its estuarySequential approach3.4 The aim of the sequential approach is to guide development away from areasat risk from flooding. Sequential approaches are already established andworking effectively in other areas in the plan-making and developmentmanagement processes (e.g. retail planning). A sequential approach is ofparticular importance at the plan-making stage and in allocating land fordevelopment by focussing development possibilities in areas at lower risk offlooding through good spatial planning. The approach is, however, alsoapplicable in the lay-out and design of development within a specific site.3.5 The sequential approach makes use of flood zones (see Box 3.1 below) for riverand coastal flooding, ignoring the presence of flood protection structures, andclassifications of vulnerability of property to flooding as described in theGlossary of Terms. It is reiterated here that the flood zones will typically bebased only on river and coastal flood inundation extents, and the risk potentiallyarising from other sources of flooding should be considered in all areas andat all stages of the planning process.3.6 In summary, the planning implications for each of the flood zones are:• Zone A - High probability of flooding. This zone defines areas withthe highest risk of flooding from rivers (i.e. more than 1% probabilityor more than 1 in 100) and the coast (i.e. more than 0.5% probability orPlanning Guidelines