WA1 Development and Flood Risk Policy
The area identified as Washland is indicated on the Proposals Map:
(i) Within Washland, development will not be permitted unless the developer is willing to provide compensatory storage and/ or flood protection to an appropriate standard as part of the development.
(ii) Where land is (a) in an area protected from tidal flooding by embankments or (b) within a floodplain but at a lower risk of fluvial flooding and the land is protected by flood embankments, which are properly maintained and provide an acceptable standard of safety, development may be permitted, subject to consultation with the Environment Agency and where necessary the imposition of appropriate conditions, for example, with respect to minimum floor level.
(iii) Development which would itself increase the risk of flooding to other properties or which would reduce the effectiveness or impede the maintenance of flood control structures or works will not be permitted.
(iv) Development which would adversely affect the integrity and continuity of tidal and fluvial defences or which would compromise the access requirements for maintenance or emergency purposes will not be permitted.
Reasoned justification :
19.2 The Proposals Map shows two areas in north Wirral which are low-lying and potentially at risk of flooding from the River Birket and from the River Fender. The Environment Agency has constructed bunds along the line of Birket, from Tarran Industrial Estate to the confluence with the River Fender, which will greatly reduce the risk of flooding to areas between the bunds and the natural limit of the flood plain.
19.3 The Proposals Map indicates areas of Washland - areas of floodplain where water will continue to inundate in times of flood - along part of the courses of the River Birket and the River Fender. This Washland is a combination of the natural floodplain unrestricted in extent - notably the upper Birket upstream of Moreton, and natural floodplain restricted in extent by artificial features such as the M53 Motorway embankments and constructed flood defence works. The flood defence works provide protection to some residential and commercial areas against flood levels up to that likely to occur once in a one hundred year period.
19.4 The areas of Washland, whether or not enclosed by these defences, as shown on the Proposals Map, must be kept clear of development which obstructs the flow of floodwater. Within areas of Washland, open space uses such as playing fields, golf courses, parks and nature reserves are acceptable, but built development will only be permitted if a compensatory amount of washland is provided elsewhere and the development is designed so as to mitigate the risk of flooding.
19.5 Outside of the Environment Agency flood defences, there remains a residual risk of flooding should the defences fail or a level of flooding occur which exceeds their design capacity. This wider area equates to the natural floodplains of the River Birket and of the River Fender and is shown on Map 4. Within this area, the second criterion of Policy WA1 indicates that development proposals will be subject to consultation with the Environment Agency and consent may be subject to the imposition of appropriate conditions. In the short term, any development on land within this area should be subject to the completion of the Birket/ Fender Environment Agency flood defences.
19.6 Map 5 shows an additional area of flood risk along the course of the River Dibbin in Bromborough to which Policy WA1 will also apply.
19.7 Much of the land around Moreton is additionally protected from flooding by the Wallasey Embankment, as shown on Map 6, and the integrity of the Embankment should not be damaged by inappropriate development. A site at the corner of Pasture Road/ Leasowe Road has been identified as an area where tidal water storage may occur following overtopping of the Wallasey Embankment in extreme tidal and weather conditions. Any development on this site would need to incorporate engineering measures which not only protected the site from flooding but did not place existing built development at greater risk.