Catchment Approach to Flood Risk Management

In December 2014 Cabinet approved a shift in approach to look at a more holistic and joined up approach to managing flood risk. This approach seeks to provide a more joined up and integrated approach to flood risk management by all authorities, agencies and communities. In September 2015 a progress report was reviewed by the ETE Select Committee on this approach and what this means in relation to next steps.

The catchment approach:

• aims to look at a whole river catchment, or sub-catchment and identify areas that are at risk and that have experienced flooding in recent events
• provides an understanding of how the catchment floods, which has not been based on administrative boundaries or flooding sources
• It makes clear that, when considering flood risk measures, there are likely to be a range of measures and options of varying in size, scale and complexity that may be appropriate
• Acknowledges that a number of authorities, agencies and communities need to come together to mitigate future flood risk

Catchment Management Plans (CMPs)

Following on from the Local Flood and Water Management Strategy and its recommendations, Hampshire has been divided into 18 river catchments with plans written for each catchment. An assessment of flood risk from a range of flooding sources has been used to identify 66 Priority Areas across Hampshire where specified actions and stricter policies will be applied. Approval for the public consultation of these Draft Catchment Plans was obtained on the 12 of May. A public consultation on these plans closed on the 21 July 2022. Following the public consultation, a Frequently Asked Questions document has been produced to address questions and comments raised during the consultation.

Following the public consultation, the catchment management plans have now been finalised and can be viewed below:

The area covered by each Catchment Management Plan can be viewed on the Catchment Area Map. The Priority Areas can also be view on our interactive Surface Water Management Asset Register map.

Guidance documents are being developed setting out how to apply the Catchment Management Plans policies in various contexts. Below are the guidance documents that are currently available:

CMP Local Plan Guidance for Local Planning Authorities

Site Allocation SUDS Land Take Calculator – for Local Planning Authorities site allocations

Superseded Surface Water Management Plans (SWMPs)

Previously the County Council has prepared Surface Water Management Plans (SWMP). The plan takes into account the risks posed by surface water flooding, including agreement about who will do what to better manage these risks. These plans have now been superseded by the draft Catchment Management Plans.

Draft Surface Water Management plans are available for Rushmoor and Eastleigh.

The draft Surface Water Management Plan focuses on surface water flood risk in the borough. It describes the significant features which can impact on surface water flood risk. It collates and assesses historic data on surface water flood events in Rushmoor and uses Defra / Environment Agency mapping data and projections to determine likely future flood risk taking into account the impacts of climate change.

Rushmoor

This data is described and assessed by Ward looking at each area’s susceptibility to flooding based on information from past flood events and the likelihood of future flooding based on national modelling data.

• Rushmoor Surface Water Management Plan (SWMP) (draft)
• Appendix A - Rushmoor Data Collection
• Appendix B - Rushmoor Borough Maps
• Appendix C - Rushmoor Flood Site Assessment
• Appendix D - Rushmoor Ward Maps
• Appendix E - Rushmoor Action Plan

Eastleigh

This data is described and assessed by Parish (including the un-parished area of Eastleigh town itself) looking at each area’s susceptibility to flooding based on information from past flood events and the likelihood of future flooding based on national modelling data.

• Surface Water Management Plan (SWMP) for Eastleigh (draft)
• Appendix A - Eastleigh Data Collection
• Appendix B - Eastleigh Borough Maps
• Appendix C - Eastleigh Flood Site Assessment
• Appendix D - Eastleigh Parish Maps
• Appendix E - Eastleigh Action Plan

The plans allow a hierarchy of flood risk in the borough to be identified along with surface water flooding ‘hotspots’ where further, more detailed work may be required into the causes of, and possible responses to, flood risk.

It highlights what solutions may be required to manage flood risk in those ‘hotspot’ areas and where further investigation is recommended.

Some flood risk management responses are proposed in the document covering a range of areas including effective communication, policy responses and physical works.

Ultimately the aim of identifying hotspots is to bring these areas to the attention of all parties who may be able to influence and reduce flood risk.

The draft SWMP was published for consultation in Spring 2013. We are currently amending the plan in the light of comments received and will publish the final version by the end of the year.

The Strategic Assessment and Background Information explains the terms used in these plans and provides overall background information across the County.