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FLOOD RISK ASSESSMENT

Issues of flooding and the location of development have become a significant issue in recent years, particularly following major UK flooding events in the late 1990's. The Environment Agency are now consulted on a Statutory basis over applications where flooding may be an issue. This is not just in coastal locations, but also low lying land in the vicinity of streams and rivers, and land where ground water levels are close to the surface and flooding occurs after heavy rain.

In circumstances where the Environment Agency consider there is a risk of flooding they may require a Flood Risk Assessment to accompany any planning application. Set out below is an extract from the relevant Planning Policy Guidance Note PPG25 which provides further guidance.

A full copy can be viewed at [Full Copy of PPG25] or at:-
http://www.odpm.gov.uk/stellent/groups/odpm_planning/documents/page/odpm_plan_606931.hcsp

To check whether your property lies in a flood risk area you can look at the maps contained on the Environment Agency website.  Once connected go to 'Choose a Section/Flood/What's in Your backyard (or insert your postcode)/Datamaps/Floodplains. These maps indicate broad levels and extent of flooding risks. Localised assessments may be necessary to update this information or deal with local circumstances not taken into account on the main maps.

There are specialist practices able to assess and provide Flood Risk advice and assessments. Full assessments which involve flood modelling can be expensive. Always seek a quotation before committing to such work.

Planning Policy Guidance 25: Development and Flood Risk [Extract]                                                                       

GENERALLY | DEVELOPERS CONTRIBUTIONS | APPLICATIONS RELEVANT TO FLOOD RISK | CONSULTATION |

| ENVIRONMENTAL IMPACT ASSESSMENT | DEVELOPMENT BEHIND EXISTING DEFENCES | CARAVAN AND CAMPING PARKS |

The susceptibility of land to flooding is a material consideration in determining planning applications. The land concerned may be that subject to the application or elsewhere if the development may have flood implications there. The potential consequences for occupiers, either of the development or elsewhere, in terms of personal safety and financial risk can be serious. Applicants for planning permission should, therefore, assess the risk posed by the development. They should consider the specific risk of flooding to the development being proposed over its currently expected lifetime and its possible effects on flood risks elsewhere in terms of its effects on flood flows and flood storage capacity and the run-off implications. Applications for renewal of planning permission should be reviewed in the light of the latest evidence on flood risk, taking into account any reviews of land allocations conducted in accordance with the guidance in paragraph 52. Such applications should, in any event, also be tested against the criteria in the sequential test set out in paragraph 30 and Table 1.

58. Applications by individual householders for minor extensions or alterations should not raise significant issues unless they are likely to have a direct and adverse effect on a watercourse or its flood defences, would impede access to flood defence and management facilities or where the cumulative impact of such developments could have a significant effect on flood storage capacity or flood flows. Such extensions or alterations should, however, be designed and constructed to conform to any flood protection already incorporated in the house being extended. Where extensions and alterations that are permitted development are likely to have a direct and adverse effect on a watercourse or its flood defences, or impede access, authorities should consider making an Article 4 Direction under the General Permitted Development Order 1995 to require planning permission so that full consideration can be given to these impacts. Each case is treated on its merits and further guidance on the policy relating to Article 4 Directions is given in DOE Circular 9/95 General Development Order Consolidation 1995.

59. Local planning authorities should ensure that within areas of flood risk identified by the Environment Agency, applicants are informed of this fact when, or preferably before, they formally submit a planning application. Where they have not already done so, authorities should also make site-specific information on their flood-risk policies part of their planning search procedures and advise those making searches to consult the Environment Agency for detailed information on flood risk.

60. In preparing their proposals, applicants should discuss with the local planning authority the requirements they will be expected to meet to satisfy the authority on flood risk and the run-off implications of the development proposed. They should consult the Environment Agency on the potential risks to their development, on the likely effects of their proposals on flood risk to others and on whether mitigation would be likely to be effective and acceptable. They should carry out an assessment of flood-risk and the run-off implications of their proposals that is appropriate to the scale and nature of the development and the risks involved and submit this with the application. Failure to do so may lead to delay in determining the application and could, in some cases, be a reason for refusal. Such assessments may require detailed hydrological investigations to determine the risks at particular sites and to inform the process of detailed design and the selection of mitigation measures. A flood-risk/run-off assessment, carried out by a suitably qualified competent person, is an essential element in the overall assessment of the economic viability of the development as well as its acceptability in planning terms. Further guidance on the content of flood-risk assessments is contained in Appendix F.

Developer contributions

61. Application of the sequential test in Table 1 may, in some circumstances, result in development being permitted that requires the provision of flood defence and mitigation works. Such provision, generally funded by the developer, is only acceptable provided it is consistent with the relevant flood-risk management policies and does not have a significant adverse impact on flood flows or storage. Local authorities and developers should have regard to the following considerations concerning the contributions developers should make to the flood defence and alleviation works required for a proposed development to proceed, because it is itself at risk of flooding and/or because it would increase the risk at other locations:

Applications relevant to flood risk

62. Applications likely to require particular consideration of flood risk issues include those for development:

Consultation

63. When they receive planning applications which they believe raises flooding issues, after having taken account of the considerations in paragraph 62 above, local planning authorities should undertake appropriate internal consultation (including the emergency services) in relation to their own flood defence responsibilities, as well as consulting the Environment Agency. The Agency is a statutory consultee for some developments (see Appendix D, paragraph D10 below) but the need to consult them in relation to flooding issues covers a much wider range of development. Local planning authorities should also, where relevant, agree with internal drainage boards the types of proposed development of interest to them and consult them on such developments within internal drainage districts and outside where they would have an impact upon them. Where run-off considerations are likely to be significant, authorities should consult the Environment Agency, the sewerage undertaker and, where relevant, any navigation authority concerned on the capacity of existing drainage systems, the feasibility and desirability of using sustainable drainage systems and the impacts of discharges into watercourses.

64. Government expects the Environment Agency and other bodies referred to in paragraph 63 to respond to consultations on the flooding aspects of planning applications within 21 days. Since consideration of the possible consequences of new development can be both time- and labour-intensive, local planning authorities should encourage applicants to provide the fullest possible information at the earliest possible stage. There are, therefore, obvious benefits in applicants discussing their proposals with the local planning authority and consulting the Agency and other bodies with an interest before an application is submitted. In responding to consultation, the Agency (and any other operating authorities) will consider the risk of flooding at the proposed site, the impact on flooding elsewhere or the impact of flood alleviation works on other property or nature conservation interests. It may then indicate that the proposal is acceptable, advise on conditions or modifications to make it acceptable, seek more information to enable a decision to be taken or object that the application is not acceptable and cannot be made so by attaching conditions or seeking modifications.

65. Where they conclude that other material considerations outweigh the objections of the Environment Agency or other consultees on flooding issues, local planning authorities should inform them that they are minded to grant permission and the reasons for doing so and give them the opportunity to make further representations. While consultees may maintain their objections, there might be practicable improvements that could be incorporated which would minimise the perceived adverse impacts on their interests. It is important that where objections are maintained, this can be justified as reasonable in all the circumstances.

66. Consultees making and sustaining objections to development proposals on flood-risk grounds should bear in mind that they may be called upon to maintain their objections in any appeal by an applicant against the refusal of permission or the imposing of conditions based on their advice. In view of the increased weight that the Government wishes to be given to flood risk in the planning process, it is obviously important that objections on flood-risk grounds are well founded and will stand scrutiny on appeal.

67. Consultation arrangements may need to make special provision for:

Environmental impact assessment

68. For certain types of project, including flood relief works, local planning authorities will need to determine whether environmental impact assessment (EIA) is required under the Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 1999. In addition, land drainage improvements that are permitted development under the General Permitted Development Order 1995 may require EIA under the Environmental Impact Assessment (Land Drainage Improvement Works) Regulations 1999. Where the development is likely to have significant effects on the environment, an EIA must be carried out. Developers should contact the local planning authority as early as possible to determine whether EIA is needed and, if so, what it should cover. The impact of development on flood risk is likely to be a significant element in the EIA, particularly where it is likely to impact on designated conservation sites or compromise river and shoreline management options or biodiversity action plans. Further advice on EIA is contained in DETR Circular 02/99.

Development behind existing defences

69. Further development on land protected by sea defences would be extremely vulnerable in the event of any overtopping or breaching of those defences because of the speed of flooding in such circumstances. A breach occurring as a result of a storm or a tidal surge, for example, might involve high risk of loss of life as well as extensive severe damage to and destruction of property. Planning authorities should take this risk fully into account when considering applications for development on such land, particularly in respect of single-storey developments with no means of escape to an upper floor. Subject to the sequential test in paragraph 30 and Table 1, such development should not be permitted where the existing flood defences, properly maintained and in combination with agreed warning and evacuation arrangements, would not provide an acceptable standard of safety. Similarly, for development behind river flood defences, consideration should be given to the need for the risks to be minimised by incorporation of appropriate flood protection measures in the design and construction of buildings. Details of such measures are contained in the report prepared by the Building Research Establishment Scottish Laboratory on Design guidance on flood damage to buildings (1996).

Caravan and camping sites

70. Caravan, camping and other temporary occupancy sites give rise to special problems in relation to flooding. They have often been located on coastal or riverside sites with a high risk of flooding. The instability of caravans places their occupants at special risk and it may be difficult to operate an effective flood warning system. Such development should be refused in the areas at highest risk, where overtopping or breach of defences would lead to rapid inundation, as should proposed changes of use to residential mobile homes or permanent housing. Where permission is granted for caravan/camping sites or other temporary holiday accommodation, a planning condition should require the erection of suitable warning notices to inform people entering the site and the preparation of effective warning and evacuation plans. Advice on the way that such matters might be approached is given in Appendix G. It is strongly recommended that sites licensed under the Caravan Sites and Control of Development Act 1960, which do not require planning permission, should have similar warnings and plans. Caravanning and camping organisations should liaise with the local planning authority and the Environment Agency about any flooding risks which might apply and the arrangements for notifying users of the warning systems and evacuation procedures.

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