Flood consequence assessment

Flood Consequence Assessment

A Flood Consequent Assessment or flood risk assessment will help you to understand the risk of flooding to your site. In Wales, a Flood Consequence Assessment report is required for developments located in flood zones C1 and C2. For developments located in flood zone B, site levels need to be checked against extreme flood outline levels which are provided by Natural Resources Wales.

There are three categories of Flood Consequence Assessment depending upon the risk of flooding to your site and the stage of the development.

Flood Consequence Assessment Level 1 – Screening Study

The Stage 1 Flood Consequence Assessment or flood risk assessment is a desk-based study utilising information and data collated from a number of stakeholders including Natural Resources Wales, the Local Planning Authority and other consultees such as water utility companies. The study provides a general indication of the potential flood risk to the site and identifies whether there are any flooding or surface water management issues that may warrant further consideration or may affect the feasibility of development. The purpose of a Level 1 Screening Study is to ascertain all sources of flood risk and whether any further work in the form of a Level 2 Flood Consequence Assessment (Scoping Study) or Level 3 Flood Consequence Assessment (Detailed Study) is required. It may also confirm that the site is at low risk of flooding from all sources.

Flood Consequence Assessment Level 2 – Scoping Study:

The Stage 2 Flood Consequence Assessment or flood risk assessment provides a qualitative appraisal of flood risk posed to the site and potential impacts development will have on flood risk elsewhere. Production of Flood Consequence Assessment Scoping Study Report including possible measures to reduce flood risk for submission to Natural Resources Wales for comment/approval, all in accordance with TAN15 July 2004.

Level 2 assessments provide a qualitative appraisal to develop an understanding of the risk of flooding to the site and the potential impacts the development will have on flood risk elsewhere.

Flood Consequence Assessment Level 3 – Detailed Study:

A level 3 Flood Consequence Assessment would be undertaken if Natural Resources Wales require further quantitative analysis to assess flood risk issues relating to the proposed development site. Flood Modelling, catchment analysis, and hydraulic calculations may be required to establish flood levels at a site where the Natural Resources Wales do not hold flood level data for the site.

For more information about flood-consequence assessments call us on 029 2065 0331.