Technical Advice Note 15 (TAN15)

CES have significant experience in assessing flood risk for development in relation to Technical Advice Note 15 (TAN15).

We offer a set price initial assessment service for Flood Consequences Assessments in Wales. The service involves site a visit, discussions with the client and Environment Agency and the preparation of an initial assessment report for a fixed cost of £600 plus VAT and traveling expenses (The fixed cost does not include for topographic surveys or charges for information from the Environment Agency which may or may not be necessary). On completion of the report we can look towards preparing the assessment working either to a fixed price or an hourly rate (to be agreed).

National policy relating to Development and Flood Risk in Wales is now covered under the Technical Advice Note 15 (TAN15). Flood risk areas have been published in the Development Advice Mapping (DAM) issued by the Welsh Assembly using Environment Agency flood risk data.

There are four classifications of flood risk zone in Wales; these are A, B, C1 and C2. Proposed development within either C1 or C2 designated areas is considered to be “at risk” from flooding during the more significant flood events.

Development type is also categorised within the TAN15 guidance. Residential development is categorised as “highly vulnerable” and would not normally be permitted in C2 designated areas, as the Environment Agency will object to the local planning authority when consulted under the planning process.

In order to request that the Environment Agency removes its objection to development in zone C2 sites, it is necessary to demonstrate that either the development is not as vulnerable as thought, or that the Welsh Assembly Flood Mapping for the specific area is incorrect. If the mapping area can be re-classified as a C1 or even a B area, then the development will have a better chance of being permitted.

To justify development in C1 areas, it is necessary to firstly demonstrate that the development can be justified on planning grounds. A Flood Consequence Assessment report (FCA) will also be required:

Justification of the development within a C1 zone is achieved if it can be shown that the development is necessary to assist or be part of a local regeneration strategy or initiative or form part of an employment objective.

FCA reports will be required for developments in Zones C1 and C2. For development in zone B, a less in-depth study is required. This is usually satisfied by checking that the proposed site levels be checked against the anticipated extreme flood levels (provided by the Environment Agency).

TAN15 provides guidance on the requirements for the preparation of Flood Consequence Assessment reports. The report needs to examine the available data relating to flood issues at the proposed site, and consider the likely mechanisms of flooding, including allowances for climate change and increased storminess. The following list provides a basis for the information to be considered within an assessment.

The Flood Consequence Assessment report details what conditions should be imposed on the development to ensure no additional risk to life and minimal damage or disruption to people, property and the natural environment.

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