Flood risk

When the planning application was submitted  and according to the initial consultants’ report the Environment Agency classified the site as Flood Risk 3.


By the time the application was put on the agenda for the planning committee in Aug 2018, the site had apparently been reclassified as flood zone 1. However, all the surrounding area remains flood zone 3 so in a flood situation the proposed development would be marooned.

This is an extract from the consultants’ environmental report :

The location of the site within Flood Zone 3 means there would be a presumption against development for more vulnerable types of development (e.g. housing, schools) in favour of developing sites within the Shepway administrative area at lower risk of flooding.

Where SDC can demonstrate through application of the ‘sequential test’ and ‘exception test'(detailed in the National Planning Policy Framework (NPPF) that there are no other alternative or more suitable sites for development within the borough, then it would be possible to develop the site. Part of the evidence that would be used to inform the exception test would be data on the hazard to the site.

Should development of the site proceed based on the current SFRA Flood Zone 1 hazard classification of the site, data on the hazard should also be used to ensure the most vulnerable types of development are guided to the areas of lowest hazard within the site. Hazard mapping should be used to assist the siting of development types across the site, this would categorise the flood hazards present on the site arising from a flood (i.e breach of local coastal defences) enabling Master Planners to site vulnerable development types (e.g. housing) in those areas of the site with the lowest hazards, whilst areas of relatively greater hazard could be used for other low risk land uses such as car parks, leisure facilities or public open space.

The latest (July 2015) flood risk assessment for Shepway still shows the site in flood zone 3:


and the flood map:


and the flood hazard map:


The flood risk report included in the planning application admits that Princes Parade is in flood zone 3. The report argues that Princes Parade lies in zone 3a (high probability of flooding) as opposed to zone 3b (the functional floodplain). It claims that the Environment Agency flood maps are “high level” and do not take into account things like local flood defences. The report claims that according  to more detailed studies, Princes Parade lies in a less hazardous part of flood zone 3a. (Where there is a shortage of developable land , local authorities are allowed to consider development in the less riskier flood zone areas – the “sequential test”.)

If a zone 3a site passes the sequential test then the exception test has to be applied where the development is considered more vulnerable. Housing falls into the more vulnerable category. To pass this test the applicant has to prove that the wider sustainability benefits to the community outweigh the flood risk and and also has to carry out a site specific risk assessment to show that the development will be safe thoughout its lifetime and won’t increase the flood risk elsewhere.

The report then looks at all the possible different sources of flooding and concludes that the only main risk is wave overtopping.

The report recommends : that the finished floor level of all buildings should be at least 600mm above the level of the promenade; flood resilience measures should be incorporated into the design of the building – eg high quality door and window fittings; the occupants should sign up to the Environment Agency flood warnings.

The plan was that the surface water would be discharged into the sea.  Kent County Council had agreed with this approach – you can read their letter here: KCC Suds

However the new documents published in July 2018 state that the plan is now to discharge the surface water into the canal:

additional – covering letter

additional -surface water drainage

The Herrington’s study referred to in the covering letter has not been supplied to the planning officers.

You can read the full report here: Flood Risk Report

Here are the comments we submitted to the planning application on the subject of flooding:

The NPPF states that only where there are no reasonably available sites in Flood Zones 1 and 2, should decision makers, consider the suitability of Flood Zone 3, taking into account the flood risk vulnerability of land uses, and applying the Exception Test if required.

The Exception Test is required if following the application of the Sequential Test it is not possible or consistent with wider sustainability objectives for the development to be located in zones of lower probability of flooding , the Exception Test can be applied. The siting of dwellings and hotels in flood zone 3a requires that the Exception Test is applied.

For the Exception Test to be passed, there are 2 criteria that must be satisfied, and these are listed below;

  • 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. (source: Shepway District Council SFRA July 2015)

The Council has carried out both a Sequential Test and an Exception Test in relation to this proposal. However, in submitting this application, rather than pursuing the allocation of the land through the Development Plan process they have not demonstrated that there are no other sites in less vulnerable flood zones where the these uses could be accommodated. The Council’s evidence has not been tested through public consultation or Public Inquiry. There are clearly other housing sites available with consent or allocated which meet the Councils housing need now. Additionally there is another site identified for a leisure centre at Nicholls Quarry. There is therefore no need to develop on this site which has a high probability of flooding.

In relation to the Exception Test it is recognised that the provision of housing and a leisure centre can be a community benefit .However in relation to housing,  Shepway has more than sufficient land to meet its housing need now. In relation to the leisure centre the Council does not know whether the use is viable, and there is an alternative site in any case. Therefore this proposal does not provide sustainability benefits for the community.  

 To overcome the risk to buildings and people on the site itself, it is proposed in the application to create a plinth 1.1m above the existing promenade off which all development will be constructed. This may have the unfortunate consequence of pushing flood water elsewhere and creating a greater depth of flood on adjoining land which would be in conflict with the advice contained in para 100 of the NPPF. The Council’s Flood risk assessment states that this will not happen but does not explain why not.

There is additionally, the question of drainage. As the site is a former tip, the site cannot be drained into the ground, using soakaways because of the contamination. It is proposed to tank the hard surfaced areas, and drain them, via pipes to the beach. The buildings would be drained by pipes directly to the beach. Such an approach is satisfactory during normal weather conditions, but if heavy rain is combined with a high sea level and overtopping, will it prevent water from the site draining to the sea, and actually cause flooding on the site?

Given the Council’s conclusions on the acceptability of development on Princes Parade, it is odd that the development of the golf course land which is also in flood zone 3a is unacceptable because of flood risk. In the absence of the testing of the evidence that supports the Council’s sequential test as to whether there are preferable sites, little weight should be given to it.

This proposal results in vulnerable land uses, being sited in an area of a high probability of flooding. The Council cannot demonstrate that the uses cannot be accommodated in less vulnerable locations because they clearly can be, and they have not demonstrated an overriding need. This proposal is in conflict with the advice contained in the NPPF.