Level 2 Strategic Flood Risk Assessment (.pdf ... - Wigan Council

Again, avoiding generalities, we have not simply “assumed” but have instead assessedeach of the identified sites and defence locations to confirm whether or not defencesprovide a continuous extent of protection to individual sites. As defences are currentlybetween a 40 and 50 year standard they will be overwhelmed during the design eventscenario.Working with the Council we have focused our assessment on avoiding, where possible,development in high risk areas. Assessment of breach scenarios for lower return periodsis significantly less onerous than designing to the 100 year (including climate change)scenario. Assessment of these lower events does not alter any substantive informationor the conclusions in the Sequential Test Spread sheet. The EA are correct not to pursuethis issue further.EA comment:We would agree with JBA and the assumed ‘undefended scenario’ for sequential testingof key regeneration sites.However it is also noted by JBA that all but key regeneration sites have been deleted inflood zone 3. PPS25 is clear in that where development cannot be located outside of highflood risk areas, the level 2 SFRA should provide further information to satisfy the‘Exception Test’. (See response to Flood Risk Guidance below).Again this has been achieved in consultation with the Council. The remaining sites withinhigher risk areas have been identified by you as being key to regeneration within Wigan.The SFRA cannot, in itself, determine whether or not the Exceptions Test can be“satisfied”. The EA is wrong to suggest that the SFRA can achieve this as considerationsfor the Exceptions Test are dependent on a variety of planning issues and constraints.The SFRA does, however, provide the flood risk information that the Council requires tomake these informed planning decisions. There are three parts to the Exceptions Test:The Council must demonstrate that:a. The development provides wider sustainability benefits to the community thatoutweigh flood risk, informed by the SFRA…b. The development should be on developable previously-developed land or, if it isnot on previously developed land, that there are no reasonable alternative sites…The Council/developer must also preparec. An FRA that demonstrates that the development will be safe, without increasingflood risk…EA comment:River Douglas Flood Alleviation SchemeWe are aware from discussions for a proposed development site within Wigan TownCentre, that the Council has already commissioned JBA to develop a breach model forthe defences on the River Douglas.As far I we are aware this is a breach model of one particular defence and not the“defences on the River Douglas”.2009s0578-S-L007-1.doc 3/710 December 2010www.jbaconsulting.co.uk