Norfolk House Hotel Development Gatwick Airport. Flood Risk Statement. May Bloc Hotels. Vantage Planning Ltd.

Transcription

1 Development Gatwick Airport May 2012 Bloc Hotels Vantage Planning Ltd Vantage Planning Ltd

2 Contents 1. Introduction The Proposed Development The Development Site Flood Risk Policy Flood Risk Vulnerability of Proposed Development to Flooding Impact of Proposed Development on Flood Risk Conclusions... 7 Page 1

3 1. Introduction This accompanies a planning application for the change of use of Norfolk House (an office building located on the roof of South Terminal, Gatwick Airport) to hotel use It has been prepared following a pre-application consultation with the Environment Agency. Although the development site lies within an area of the airport that is at risk of flooding, the elevated position of Norfolk House (and the fact that it does not extend down to ground level) means that the building itself is not considered to be at risk of flooding. It has therefore been agreed in pre application discussions with the Environment Agency and Crawley Borough Council that a formal full FRA is not required. This Flood Risk Statement has, however, been prepared to demonstrate the acceptability of the development in regard to flood risk considerations. 2. The Proposed Development The proposed development is to change the use of Norfolk House, South Terminal Gatwick, from its existing office use to use as a 245 bedroom hotel. The development will also entail external changes to the appearance of the building through changes to the fenestration. re-cladding and roof plant. 3. The Development Site The application site is an existing rectangular office building extending above the roof of Gatwick Airport s South Terminal. Photo from Inter-Terminal Transit System Page 2

4 It comprises four floors of office accommodation, with a gross internal floorspace of some 4,644m 2, and a section of roof plant. It is currently accessed via lifts from the South Terminal check-in concourse (Level 2 of South Terminal) and the Village shopping level (Level 3). The proposed hotel reception is planned to be provided at Level 3. Photo from South Terminal Multi Storey Car Park 3 4. Flood Risk Policy National Planning Policy Framework National Government policy with respect to development and flood risk is contained within the National Planning Policy Framework and the accompanying Technical Guidance Note. The policy is to seek to prevent inappropriate development in areas at risk of flooding to avoid where possible flood risk to people and property. The guidance identifies sequential and exceptions tests to steer development to areas with the lowest risk of flooding. Where new development is necessary in such areas, the policy aims to make it safe without increasing flood risk elsewhere, and where possible reducing flood risk overall. Page 3

5 The Sequential Test states that the overall aim of decision makers should be to steer new development to Flood Zone 1 - land at lowest probability of flooding. Where there are no reasonably available sites in Flood Zone 1, sites in Flood Zone 2 may be considered, taking into account the vulnerability of land uses. Only where there are no reasonably available sites in Flood Zones 1 or 2 should sites in Flood Zone 3 be considered, taking into account the vulnerability of land uses. For more vulnerable land uses proposed in Flood Zones 2 and 3 an Exception Test is also required to be passed before development can be permitted. Table 1 sets out the circumstances for where particular developments are appropriate having regard to flood risk. Table 1: Flood Zones, referring to the probability of river and sea flooding, ignoring the presence of defences. Flood Zone Definition Appropriate land uses Flood Zone 1: Low Probability Land with less than a 1 in 1000 annual probability of river or sea flooding in any year (<0.1 %). All land uses are appropriate. Flood Zone 2: Medium Probability Land with between a 1 in 100 and 1 in 1000 annual probability of river flooding (1% - 0.1%), or between a 1 in 200 and 1 in 1000 annual probability of sea flooding (0.5% - 0.1%) in any year. Water-compatible, less vulnerable and more vulnerable land uses and essential infrastructure are appropriate. Highly vulnerable land uses are only appropriate if the Exception Test is passed. Flood Zone 3a: High Probability Land with a 1 in 100 or greater annual probability of river flooding (>1%), or a 1 in 200 or greater annual probability of flooding from the sea (>0.5%) in any year. Water-compatible and less vulnerable uses are appropriate. More vulnerable and essential infrastructure uses are only appropriate if the Exception Test is passed. Highly vulnerable uses should not be permitted. Flood Zone 3b: The Functional Floodplain Land where water has to flow or be stored in times of flood. Land which would flood with an annual probability of 1 in 20 (5%) or greater in any year, or is designed to flood in an extreme (0.1%) flood, or at another probability agreed between the Local Planning Authority and Environment Agency, including water conveyance routes. Water-compatible uses are appropriate. Essential infrastructure is only appropriate if the Exception Test is passed. All other land uses should not be permitted. Page 4

6 5. Flood Risk Crawley Borough Strategic Flood Risk Assessment Crawley Borough Council Strategic Flood Risk Assessment (SFRA) provides an overview of flood risk in the Borough, to inform planning policy and decisions on planning applications. Fluvial Flood Risk The following extract from the SFRA, shows the location of Norfolk House in relation to the flood risk zones. It is emphasises that Norfolk House is a building located on the roof of South Terminal such that no part of the Norfolk House building, is at risk of fluvial flooding. Figure 1: Flood Zone Plan (Source: Crawley SFRA) Position of Norfolk House Page 5

7 6. Vulnerability of Proposed Development to Flooding The proposal is to change the use of the building from offices to hotel. Table 2 of the NPPF Technical Guidance on flood risk classifies the vulnerability to flooding of a range of different land uses (See Table 2 below). Hotels are classified as more vulnerable to flooding than offices which are classified as less vulnerable. Table 2: Flood Risk Vulnerability Classification (based on Table 2 of NPPF Technical Guidance) Even though the hotel is more vulnerable, the location of the proposed development within a building which is located wholly above the area at risk of flooding is such that it is not a building which is susceptible to flooding. Page 6

8 Furthermore all guests will enter and exit the hotel from within South Terminal at the hotels reception which is to be located at Level 3 of the Terminal. The lowest bedrooms will be at Terminal Level 5 (the ground floor of Norfolk House). In the event of a flood affecting South Terminal no employees or guests of the hotel would be exposed to risk of flooding. All would be able to safely arrive and depart the hotel via safe means of access and escape. Despite its location at South Terminal, where there remains a general risk of flooding, and its classification as more vulnerable the proposed development, would therefore be appropriate and acceptable. 7. Impact of Proposed Development on Flood Risk There are no plans to alter any hard standing areas or surface water drainage from the site. Surface water will continue to drain off from the roof of the building through the existing drainage pipes which connect to the airport s surface water drainage system. There will be no structures erected on site that would block or change flow paths of any flood water. The development will not therefore increase flood risk elsewhere. 8. Conclusions Although parts of Gatwick South Terminal lie within an area at risk of flooding, Norfolk House is an elevated building located well above the flood risk zone. The proposed hotel will not be at risk of flooding. In the event of flooding at South Terminal safe access and egress is readily available to hotel staff and guests. The proposed development would therefore be appropriate and acceptable despite its location at South Terminal and its classification as more vulnerable. The development will not increase flood risk elsewhere. Page 7