Managing flood risk

Information for developers on surface water flooding, causal areas and dry islands

Surface water flooding

You can use our flooding impact form to help your small-scale developments meet the requirements of the local plan flood policy NBE5. The aim of the form is to smooth the planning application process for small-scale developments in areas that flood from surface water.  

Sites at risk from any source of flooding are required to provide a flood risk assessment. Our strategic flood risk assessment has identified areas where flooding from other sources is possible. You can view these areas on the Hart online maps under the Environment tab in the left-hand menu.  

You should consider using the flooding impact form for sites of less than 1 ha in flood zone 1 that flood from surface water. You can check if your site floods from surface water on the Environment Agency's maps

Please submit the completed form with the rest of your planning application documents.

Betterment options

At the start of the flooding impact form, we'll give you a list of potential betterment options and ask you to choose a preferred option and a back-up option. In some cases, it may not be clear until later in the planning process whether the betterment proposed is viable. You'll only have to do your back-up option if your first option proves not to be possible.

We recognise the list we provide may not be exhaustive. You can include a measure that is not listed but it must be agreed with the Council’s drainage engineer.

You'll be asked to provide evidence of your chosen options by uploading a submitted plan or document. You should make sure that the chosen option is likely to be feasible at the development.

For example, the option ‘surface water is being disposed of via infiltration’ is unlikely to be accepted if the development site is located on clay, as infiltration is unlikely to work.

Complete flooding impact form

Please read our technical note 1 on level for level flood compensation

Causal areas

Causal areas drain into the areas of Hart most likely to flood. Developments in these areas should take steps to prevent flooding. If all developments take these steps, the combined effect should help protect flood-prone properties across the area. 

You can check if your site is in a causal area on Hart District Council online maps. Causal areas are under the environment map category. 

Dry islands 

Dry islands are areas that don’t flood directly from rivers, but may be cut off from other parts of Hart during a flood event.

If you're planning a development in flood zone 2 or 3, or on a dry island, you should ensure residents can get on or off the site in the event of a flood or consider alternative ways of managing these risks to site users. This is commonly known as access and egress.

This is necessary if your development will either increase the number of dwellings or increase the development’s vulnerability to flooding. For example, this might occur if land use changes from commercial to residential.  

The information below should guide developments where access and egress is an issue: