Portsmouth City Council’s overall aim is to reduce the risks to people and property from flooding. When drawing up plans or considering applications for development, we try to direct development to sites at lower risk of flooding. To be able to do this, we need to know as much as possible about the flooding risks in the city.

We have carried out several assessments, listed below. All assessments and reports, along with relevant annexes and maps, can be downloaded in PDF format.

For further information on the work we are doing in the city email drainageteam@portsmouthcc.gov.uk, phone 023 9284 1588 or contact the coastal and drainage team at Portsmouth City Council, Civic Offices, Guildhall Square, Portsmouth, PO1 2NE.

Preliminary Flood Risk Assessment

Portsmouth’s Preliminary Flood Risk Assessment was completed in June 2011. This assessment is a high level screening exercise to collect information on past historic and future potential floods. This information was then used to identify flood risk areas in the city.

Surface Water Management Plan (SWMP)

Surface water means rainfall before it enters the underground drainage systems, plus groundwater and ordinary watercourses.

The Surface Water Management Plan (SWMP) follows on from the Preliminary Flood Risk Assessment, increasing the council’s understanding of the causes, probability and consequences of surface water flooding. It details surface water flooding issues on a local level, primarily concerning the health, safety and wellbeing of Portsmouth residents and businesses. It does not include extremely localised flooding caused by infrastructure failure, such as a gutter drain blocked by leaves.

The SWMP has allowed us to identify and prioritise the areas at greatest risk. The work that comes from the SWMP and later the Local Flooding Risk Management Strategy (see below) will be focused on, but not limited to, reducing the flood risks in the fourteen hotspot areas.

Local Flood Risk Management Strategy (LFRMS)

As a designated lead local flood authority, Portsmouth City Council has completed a Local Flood Risk Management Strategy (LFRMS) to recommend measures to manage and improve the flood risk of the city. As funding is limited, the strategy includes the costs for each measure and the benefits each will provide. This approach allows funds to be targeted to areas where the benefits will be greatest.

The strategy is focused on a ward by ward basis, and has been approved by our flood risk management partners and Portsmouth City Council’s Chief Executive Officer for publication.

Strategic Flood Risk Assessment

The joint Strategic Flood Risk Assessment commissioned by the Partnership for Urban South Hampshire (PUSH) for our region is currently being reviewed.

In the meantime, you can use the GOV.UK flood map for planning tool to find out which flood zone a location is in. If you’re planning a development you may need to undertake a more detailed flood risk assessment depending on what zone it is located within.