Sequential and Exception Test

We are experienced in the Application of the Exception Test for flood risk assessments. Our nationwide experience allows us to draw on numerous examples across the UK. The core principals of the sequential and exception tests are to ensure that new developments which are needed in medium or high flood risk areas will only occur where flood risk is clearly outweighed by other sustainability factors and the development will be safe for its lifetime, taking climate change into account.

The sequential assessment of prospective development sites within flood zones was further strengthened through the introduction of PPS25, and then carried forwards into the National Planning Policy Framework.

A sequential test is a comparative analysis of the application site and other potential sites within the local authority, or determined comparison area. The assessment requires liaison with the Local Planning Authority to obtain and assess the current land availability supply within the study area. It also includes negotiation with the Environmental Regulator and Local Planning authority to inform the initial study parameters such as study area and development threshold.

The Sequential Approach

The sequential approach is a simple decision-making tool designed to ensure that areas at little or no risk of flooding are developed in preference to areas at higher risk. Local Planning Authorities should make the most appropriate use of land to minimise flood risk, substituting land uses so that the most vulnerable development is located in the lowest risk areas. They should also make the most of opportunities to reduce flood risk, e.g. creating flood storage and flood pathways when looking at large scale developments.

The aim should be to keep all development out of medium and high flood risk areas (Flood Zones 2 and 3 and other areas affected by other sources of flooding) where possible. All opportunities to locate new water-incompatible developments in reasonably available areas of little or no flood risk should be explored, prior to any decision to locate them in areas of higher risk.

The Enzygo Way

We are experienced in undertaking Sequential and Exception tests, our integrated planning and hydrology teams are able to provide joined up advise taking into account housing allocations and flood zones. We have undertaken sequential and exception tests for residential, commercial, retail, industrial sites and waste related infrastructure.

Our 1D and 2D modelling expertise is invaluable in helping clients to demonstrate through mitigation that the site will meet the exceptions test criteria by being safe from flooding.


Hydrology Team

For a quotation or if you need some advice relating to flooding, click the link above to contact our Hydrology Team. You can either contact us by phone or email and we will respond to you within 24 hours.

Current Flood Warnings from the Environment Agency

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