Phase 4 of the North Portsea Island Coastal Flood Defence Scheme

NPI Phase 4 Pre-Construction Event

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Portsmouth locals will have the chance to find out more at a pre-construction exhibition focusing on the next stage of coastal defences which will protect North Portsea Island from the risk of coastal flooding.In the lead up to the start of construction, a public exhibition is being held at The Great Salterns Mansion Harvester, Eastern Road, Portsmouth on Wednesday 14thAugust between 1pm – 7pm. At the exhibition the scheme plans will be on display, as well as information on what to expect during construction and timescales for delivery. Project staff will also be on hand to answer any further questions. This event follows on from previous public consultation held in March 2014, January 2015, April 2016, February 2017 and November 2018 which helped shaped the design of the scheme following public feedback.

 Artist’s impression of defences North of Sailing Club

The next phase of defences will be delivered in two parts, the first involving the construction of an earth embankment, a steel sheet pile wall and raising the road adjacent to Kendall's Wharf on Eastern Road. The second stage includes the construction of a seawall along 2.4km of the Eastern Road, encasing the existing seawall and raising the defence level by approximately 1.2m. The principle design for Phase 4 is now complete and construction on the first package of work is due to start in September 2019 on the Kendall’s Wharf section, which has just been approved by the local planning authority, and is expected to be completed by April 2020.

The planning application for the second package of work, taking place along Eastern Road is due to be submitted in August 2019. Subject to planning approval, work could begin on this section of the defences in April 2020 with a view to being completed in late 2022. The designs for the second package of work will also be on display at the exhibition. Councillor Dave Ashmore, cabinet member for environment and climate change at Portsmouth City Council said, "This event is a great opportunity to engage again with the public in the area about the new defences which are needed to protect Portsmouth from a flood event. There has been plenty of consultation already on the design of these defences which will add to the great work which has taken place at Anchorage Park, Milton Common and currently at Tipner".

Artist’s impression of defences South of Harvester

The North Portsea Island Scheme, which is being delivered by the Eastern Solent Coastal Partnership on behalf of Portsmouth City Council, covers 8.4km of coastline from Tipner through to Milton. Most of the area is low-lying and many of the current coastal defences are approaching the end of their effective lives. The new coastal defences are designed to significantly reduce the risk of coastal flooding over the next 100 years, reducing the risk of flooding from the sea to over 4,200 homes, 500 businesses and critical infrastructure including Eastern Road. On completion, the scheme will offer protection against a 1 in 500 year coastal flood event and will tie in with the defences built at Anchorage Park to the North and Milton Common to the South.

See the drop in exhibition leaflet here: https://www.escp.org.uk/sites/default/files/news_documents/NPI%20Leaflet_0.pdf

To view the November 2018 information booklet, click here!

To view FAQ's please click here, or to view the FAQ webpage click here


Phase 4 of the North Portsea Island Coastal Flood Defence Scheme

New coastal defences are being built as part of the North Portsea Island Coastal Flood Defence Scheme, which have been designed to reduce the risk of coastal flooding and erosion to the area over the next century.  The Eastern Solent Coastal Partnership have successfully gained approval and Flood Defence Grant in Aid funding for £58.5million to implement these works, which when constructed, will provide one of the highest standards of coastal flooding protection in the country.  The implementation project has been split into five phases of works, two of which are complete and the third phase is under construction.

  • Phase 1 -Anchorage Park: the construction of 1.4km of earth embankment with rock revetment toe completed in 2016 at a cost of c.£5m;
  • Phase 2 - Milton Common: the construction of 1.5km of set back earth embankments and rock revetment structure, completed in 2016 at a  c.£3m;)
  • Phase 3 - Tipner Lake: is the construction of 1.9km of a seawall which commenced April 2017 and is programmed for completion by the end of Autumn 2019;
  • Phase 4 – Eastern Road and Kendall’s Wharf: is the construction of a seawall with road raising at the entrance to Kendall’s Wharf;Phase 5 – Ports Creek: 1.3km of earth embankment with a rock revetment toe to be constructed in 2023 and 2024.

Phase 4 is the next phase of works with a combination of two distinct sections: Kendall’s Wharf and Eastern Road.  The full length of the frontage is 2.4km (300m for Kendall’s Wharf and 2.1km for Eastern Road).  Construction is due to start in September 2019, with completion of the construction works by October 2022 excluding landscaping works which will be completed by February 2023.

The new defences at Kendall’s Wharf will tie in with those built at Anchorage Park in 2016.


Figure 1:Anchorage park completed

The first c.150m of sea defence will be a raised earth embankment with a continuation of the 3m wide coastal path.  This embankment will tie into the area of road raising landward of Kendall’s Wharf, where the road will be raised by approximately 1m.  South of the road will be 150m of steel sheet pile wall and will tie into the coastal defences at Eastern Road.

 Figure 2: Artist impression of cross section

                Figure 3: Artist impression of cross section

At Eastern Road the works will include the demolition and removal of the existing seawall in the southern section of the site, and the construction of a vertical reinforced wall with a stepped revetment.  In the northern section, the existing seawall will be encased and the existing path behind the seawall reconstructed. Landscaping works will be carried out to enhance this much loved coastal region including new access points to a public footpath, four slipways and three access steps.  

In addition to reducing the flood risk for North Portsea, Phase 4 of the works will introduce environmental enhancements to the area.  Enhancements include texturizing part of the seaward face of the wall to encourage marine growth and habitation.  We will also be introducing tidal pools to the foreshore and introducing an offshore bird island, creating important habitats as a high tide roost site for birds.

Figure 4: High roost site for birds – artist impression

The project team look forward to sharing more information on this phase of the project during summer 2018.