Issue details

To provide an overview of the outline design of the Portchester to Paulsgrove Coastal Flood and Erosion Risk Management (CFERM) Scheme.

To provide financial information on the existing Professionals Services Contract to deliver the outline design for information.

To seek Executive support for the next steps in progressing the scheme, applying for Grant in Aid funding and if successful undertaking the detailed design and construction.          

The Portchester to Paulsgrove CFERM scheme is located on the north shoreline of Portsmouth Harbour, stretching for 1.7km from Portchester Sailing Club in the West, to Port Solent in the East.

A number of the defences along the frontage are in poor condition or do not provide the required standard of protection.

There are 361 residential and 108 commercial properties at risk from a 1: 200 year present day tidal flooding event, rising to 662 residential and 141 commercial properties at risk by 2115.

Through previously securing local levy and Flood and Coastal Risk Management (FCRM) Grant in Aid funding towards the development of the scheme, an optional appraisal and outline design has been undertaken for the proposed scheme, and the proposals are presented in this report.

An affordable ‘managed adaptive approach’ to scheme delivery has been identified as the preferred option which meets with the Environment Agency funding rules. This approach means that the project would be delivered in a phased manner as and when defences fall below the required standard.

The North Solent Shoreline Management Plan, which was adopted by Fareham Borough Council in 2010, set out a policy of Hold The Line for this length of coastline.

The overall project is supported by the Portchester Castle to Emsworth coastal flood and erosion risk management strategy (“the PEM Strategy”), which was adopted by Fareham Borough Council in 2011 and approved by the Environment Agency in 2013.

After approval of the PEM Strategy, a partnership contribution to the scheme from the Trafalgar Wharf developers was tabled. It was proposed that through planning conditions Quadrant Estates could facilitate delivery of the scheme recommended by the Strategy and to a higher 1:200 year standard of protection.

Proposed scheme - The following works would be undertaken (subject to funding):

o   Southampton Road - Land raising only

o   Southern Water Pumping Station - New Revetment structure

o   Castle Shore Park - New Sloping revetment

o   Recreation Ground - Raised Capping Beam only

o   Portchester Sailing Club - New vertical sheet piled wall with concrete capping beam and setback wall to tie into high ground

Beyond the 15 year scheme it will be necessary to undertake the further phases of works to maintain reduced flood risk to the area as defences along other stretches of the frontage reach the end of their serviceable design life.

The progression of the scheme is dependant on securing the funding for the scheme from both developer contribution and FCRM Grant in Aid.

The Outline Business Case will be submitted to the Environment Agency for review in July 2017. Subject to funding, construction work is proposed to begin in 2019.