Strategic Flood Risk Assessment (Level 2) - Christchurch
Every local planning authority in England is required to conduct a Strategic Flood Risk Assessment (SFRA) to assess flood risk now and in the future, taking into account the effects of climate change. The Government requires that local planning policies use the results of the SFRA to direct development away from areas at greatest risk of flooding. The SFRA adopts the precautionary approach and illustrates a theoretical 'worst case scenario' to plan for.
National Planning Policy Statement 25 'Development and Flood Risk' (PPS25) requires local planning authorities to prepare a Strategic Flood Risk Assessment (SFRA) in consultation with the Environment Agency to refine information on areas at risk of flooding, taking into account all sources of flooding and the impacts of climate change. In their preparation of policies under the Local Development Framework, planning authorities must develop a robust evidence base. The SFRA is an essential part of that evidence.
The Level 2 SFRA for Christchurch incorporates new data and more advanced methods of modelling flood risk and has been produced in partnership with the Environment Agency. The method and content of the study are in accordance with Planning Policy Statement 25 and its associated Practice Guidance which aim to make sure that flood risk is taken into account at all stages of the planning process. The results will be used to inform the determination of planning applications and policies for future development in the Borough.
Flood risk now and in the future
The SFRA updates the existing flood zones which show the areas at risk of flooding now. Maps for current flood risk are regularly updated by the Environment Agency and published on their website.
The SFRA also projects flood risk forward into the future, taking account of predicted sea level rise and increased annual rainfall as a result of climate change. The SFRA is primarily a tool to inform the planning of future development such as new housing, schools and businesses. To make sure that these developments remain safe throughout their entire life, the Council must plan for flood risk how it will be in the future, and not just how it is now.
The SFRA therefore provides two sets of future flood mapping showing how it may theoretically be assumed to be in the years 2086 and 2126 (the SFRA report explains why these dates have been chosen).
Advice for the general public - not for planning purposes
Am I at risk now?
The good news is that as a result of the improved data and new mapping, over one fifth of the current high risk flood zone (called zone 3) in Christchurch is reduced.
To check if you are at risk of flooding, and for advice on what to do if you are, please refer to the Environment Agency Flood Maps.
Am I at risk in the future?
The SFRA projects flood risk forward to the years 2086 and 2126. Unsurprisingly, the effects of climate change mean that more areas of land slowly become at greater risk of flooding over time. Large areas of Christchurch are already protected against flooding by river and coastal defences, most notably in the town centre, west Christchurch and around the harbour.
The Environment Agency have responsibility for building and improving defences but only have funding to deal with current risk. They are unable to create new defences in areas which are not yet at serious risk of flooding. Over time however, as risk does increase, Christchurch's existing defences will be raised to maintain the current level of protection.
The maps immediately below show how flood risk would increase IF CHRISTCHURCH'S EXISTING DEFENCES WERE NOT IMPROVED OVER TIME. They show that without improvements, increasingly more land would flood. It is important to note though that defences WILL be improved, so the situation shown on these maps may never happen.
Future flood risk if defences are not improved
These maps are NOT to be used to inform planning applications or any decisions for future development.
Anyone concerned about flood risk to their property should refer to the Environment Agency Flood Mapsor call them on 01709 389 201.
Advice for developers - SFRA for planning purposes
National Government policy and the Environment Agency require that Councils plan for undefended flood risk, assuming that existing defences do not exist. This is part of the 'precautionary principle' and assumes that even the best defences could be overtopped or breached (broken through) by a very severe flood, or that essential flood gates could be left open accidentally. For all planning purposes therefore, the undefended maps provided below must be used.
The Strategic Flood Risk Assessment for Christchurch (Level 2) May 2009 consists of the following:
Undefended flood maps for YEAR 2086 (to guide planning of commercial developments):
Undefended flood maps for YEAR 2126 (to guide planning of residential developments):
Depth, velocity and hazard maps
Although the SFRA has provided MapInfo GIS (Geographical Information Systems) data showing depth (above ground level and above ordnance datum), velocity and hazard at 1m grid intervals, they have not yet been produced in a format which can be published to this website. These will be provided soon but in the meantime, please contact us using the details below for more information.