7.0 Stage 5: Flood Risk Sequential & Exceptions Test (if required) & Green Belt What does the National Planning Policy Framework say about Flood Risk for Local Plans? Para. 99 – states that Local Plans should take account of climate change over the long term, including flood risk, and plan so that development avoids increased vulnerability to impacts arising from climate change, but where development is brought forward in vulnerable areas ensure the risks are managed. Para. 100 - Inappropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk, but where development is necessary, making it safe without increasing flood risk elsewhere. Local Plans should be supported by Strategic Flood Risk Assessment and develop policies to manage flood risk from all sources, taking account of advice from the Environment Agency and other relevant flood risk management bodies, such as lead local flood authorities and internal drainage boards. Local Plans should apply a sequential, risk-based approach to the location of development to avoid where possible flood risk to people and property and manage any residual risk, taking account of the impacts of climate change, by: ● applying the Sequential Test; ● if necessary, applying the Exception Test; Para. 101 - The aim of the Sequential Test is to steer new development to areas with the lowest probability of flooding. Development should not be allocated if there are reasonably available sites appropriate for the proposed development in areas with a lower probability of flooding. The Strategic Flood Risk Assessment will provide the basis for applying this test. A sequential approach should be used in areas known to be at risk from any form of flooding. Para. 102 - If, following application of the Sequential Test, it is not possible, consistent with wider sustainability objectives, for the development to be located in zones with a lower probability of flooding, the Exception Test can be applied if appropriate. For the Exception Test to be passed: ● it must be demonstrated that the development provides wider sustainability benefits to the community that outweigh flood risk, informed by a Strategic Flood Risk Assessment where one has been prepared; and ● a site-specific flood risk assessment must demonstrate that the development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall. Both elements of the test will have to be passed for development to be allocated. What does the National Planning Practice Guidance say about Flood Risk for Local Plans? The guidance includes the following flow diagram for application of the sequential test for Local Plans. 90 A local planning authority should demonstrate through evidence that it has considered a range of options in the site allocation process, using the Strategic Flood Risk Assessment to apply the Sequential Test and the Exception Test where necessary. This can be undertaken directly or, ideally, as part of the sustainability appraisal. Where other sustainability criteria outweigh flood risk issues, the decision making process should be transparent with reasoned justifications for any decision to allocate land in areas at high flood risk in the sustainability appraisal report. The Sequential Test can also be demonstrated in a free-standing document, or as part of strategic housing land or employment land availability assessments. The guidance provides the following flow diagram for application of the Exceptions Test for Local Plans. 91 Evidence of wider sustainability benefits to the community should be provided, for instance, through the sustainability appraisal. If a potential site allocation fails to score positively against the aims and objectives of the sustainability appraisal, or is not otherwise capable of demonstrating sustainability benefits, the local planning authority should consider whether the use of planning conditions and/or planning obligations could make it do so. Where this is not possible the Exception Test has not been satisfied and the allocation should not be made. In considering an allocation in a Local Plan a level 2 Strategic Flood Risk Assessment should inform consideration of the second part of the Exception Test. 7.1 Background 7.1.1 The borough of Doncaster includes the two catchment areas of the river Don (western parts of the borough) and the river Trent (eastern parts of the borough). The river Don’s two main tributaries are the river Rother to the south and the Dearne to the north. A further two main rivers, Ea Beck and the river Went, join the Don downstream of Doncaster. The Bentley flood corridor is an area of low-lying land on the left bank of the river Don between the river Don and Bentley. The river Trent and its catchments cover parts of the north-east, south, and south-east corner of Doncaster. 7.1.2 According to the Environment Agency’s flood risk map for Planning, nearly 34% of the borough is at high risk of flooding (flood risk zone 3) with a further 9% at medium risk (flood risk zone 2) as identified on the map below. This equates to over 24,400 hectares. Areas at risk include the Main Urban Area of Doncaster (parts of Doncaster Town Centre, Bentley, Wheatley Hall Road and Kirk Sandall), Thorne-Moorends, Hatfield-Stainforth, Carcroft, Askern, and a number of other smaller villages. 92 7.1.3 However, this ‘risk’ does not take into account the presence of flood defences, as there is always a possibility that defences could fail, but some of these areas are defended by existing flood defence infrastructure. 7.1.4 Surface water flooding occurs where high levels of rainfall exceed drainage capacity in an area and these events can lead to serious flooding of property as demonstrated by the flood event in summer 2007. The topography of the borough, especially in and around a number of built-up areas, make them potentially prone to flooding caused by direct rainfall due to the amount of impermeable surfaces and the lack of sufficient sewer capacity. Areas where surface water may generate particularly high risk can be found at Intake, Bentley, Toll Bar, and Adwick-le-Street. 7.2 How will potential development sites be assessed at this stage? Flood Risk Sequential Test 7.2.1 Sites have been ranked (low to high) in order of flood risk on a settlement-by- settlement basis using the findings from the Strategic Flood Risk Assessment Level 1 (2015) and Sustainability Appraisal. This is known as the sequential test as required by national planning policy set out above. Priority to allocation should be given to sites at lowest risk of flooding first and foremost, unless it is not possible, consistent with wider sustainability, to avoid flood risk in which case consideration can be given to sites at medium risk of flooding and so forth. 7.2.2 The starting point for the sequential test is the Council’s Strategic Flood Risk Assessment Level 1 (published November 2015). However, at around the same time that this was published there was an update to the Environment Agency Flood Map for Planning (November 2015) which had a significant change for the Thorne-Moorends area of Doncaster, meaning the flood risk data in respect to some of these sites has changed. As documented at stage 1 of this methodology, the Council has also continued to receive further sites for consideration through the Local Plan process, and such sites were not originally fed into the Level 1 Assessment. The Council has therefore replicated the data from the SFRA using GIS for any such sites in order to have a consistent and up-to-date source on which to base the sequential test. This was carried out as part of the previous Sustainability Appraisal process stage 4. 7.2.3 For housing sites, the sequential test has been assessed on a settlement-by- settlement basis in line with the Local Plan’s settlement hierarchy and growth requirements. Planning permissions on sites 5+ as at the 1st April 2017 have been excluded from the test as national planning policy states that planning permissions are deliverable unless there is clear evidence to the contrary. Irrespective therefore of the flood risk constraints of planning permissions, they are considered as being deliverable and viable sites and therefore their capacity taken as the starting point for contributing towards a settlement’s Local Plan housing requirement. As discussed in the previous section, permissions that were not under construction as at 1st April 2017 have all been assessed in line with the Sustainability Appraisal Framework, which includes flood risk. Permissions have been through the Development Management process (including a sequential test in line with the Council’s adopted Development & Flood Risk SPD and Core Strategy Policy CS4) in consultation with the Environment Agency and other water risk management bodies (Lead Local Flood Authority; IDB’s; Water Authorities). They will have agreed appropriate flood risk mitigation in line with the residual risks and site specific flood risk assessment etc (see Exceptions Test below). 93 7.2.4 The remaining site options (without permission as at 1st April 2017) have then been ranked in flood risk order (low to high) using the same criteria as per objectives 11a (main river flooding) and 11b (surface water flooding) as set out in the Sustainability Appraisals stage 4. Sites in FRZ1 and not constrained from surface water flooding are all deemed to have passed the first sift of the sequential test (shown as white sites in the tables). Sites that scored a neutral (FRZ2) single negative (FRZ3a) or double negative (FRZ3b) for main river flooding (criteria 11a) or a single negative (medium/high risk) for surface water flooding (criteria 11b) have been identified as failing the first sift of the sequential test (shown as blue sites in the table).