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

68An additional document on interpretation of this guidance is given in thedocument “Irish SuDS: guidance on applying the GDSDS surface waterdrainage criteria” to be found athttp://www.irishsuds.com/guidance_ criteria.htm.These are considered key reference material for those undertaking drainageimpact assessments.2 SATISFYING THE JUSTIFICATION TESTPlanning Guidelines2.1 The Flood Risk Balance SheetIn any assessment of environmental risk a transparent record of how the riskwas assessed and is to be managed is essential. The Flood Risk Balance Sheet(See Table A2), once completed, provides a short summary of the riskassessment and the characteristics of that risk and its likely mitigation. TheFlood Risk Balance Sheet is a useful tool and should be used by planningauthorities to evaluate alternatives in making their decisions on developmentplans and local area plans especially in applying the Justification Test.The FRBS harness a number of indicators that have been developed to allowa comparison of appropriate land uses in each plan area and whether theywould satisfy the terms of the Justification Test. These indicators are:• Development is within existing flood risk area – existing flood warningand evacuation is in place. Importantly how easily will the area recoverfollowing an event? New development may lose local services for 12months if an event occurs;• Residual risk measures are easily applied and within a norm – Lowdepths of flooding can be easily designed out by modest alteration ofground or floor levels. 1st floor accommodation has implications forthe urban design and place setting of the development;• Egress and access. Impact on emergency planning provision and whetherrisks to development would be acceptable – This is a key issue andprime test in meeting the acceptable risk criterion in the JustificationTest. Access routes need to be natural and accessible in a flood to theemergency services;• Change in the number of people at risk as result of development –Introduction of more people will put a greater strain on the emergencyservices in an event. Whilst they may be accommodated at high elevationthey will require support very quickly even after the inundation hasstopped;