Beach renourishment 2005-2007, Phase I

During the winter of 2005/2006 approximately 1.16 million m³ (1.74 million tonnes) of sand dredged from Poole Harbour channels and approaches was used to renourish beaches at Swanage, Poole and Bournemouth (Hengistbury Head to Southbourne) to protect them from erosion.

Dredgers pumped sand ashore 24 hours a day, 7 days a week, including Christmas and the New Year.

• The contractors arrived on 22nd November 2005, and the beach at Swanage was renourished first;
• Work at Poole started in December and was completed on 16th January 2006
• Work at Bournemouth started 19th January and was completed 18th March 2006. These works formed part of the wider Bournemouth ‘Beach Improvement Scheme’ (BIS) and was known as BIS4.1; beaches were renourished between Hengistbury Head and Boscombe

Availability of sand

Purchasing and transporting sand from commercial sources (from licensed dredging sites south of the Isle of Wight or at the Thames Estuary) can be very expensive. So when an opportunity arises to utilise sand from local dredging operations it saves Defra – and consequently the British taxpayer – a considerable sum of money.

In 2005 Poole Harbour Commissioners (PHC) were due to dredge the harbour channels and approaches in order to increase depth from 6m to 7.5m below Chart Datum. It was also necessary to widen the Middle Ship Channel to 100m. Primarily, the deeper approach channel was required to meet the needs of modern ferries, the majority of which now have a minimum draft of over 6.5 metres, thereby securing the long-term viability of the Port

PHC dredged 2 million m³ of material from Poole Harbour channels and approaches, of which about 1.1 million m³ was suitable for beach replenishment. The remainder of the material (silts and clays) were disposed of under licence at an offshore disposal ground located off Swanage. PHC have utilised this site for the disposal of dredged material from Poole Harbour for more than 50 years.

The 1.1 million m³ of suitable material was distributed (approximately) as follows:

• Swanage beach – 90,000 m³
• Poole beaches between Shore Road and Branksome Dene Chine – 450,000 m³
• Bournemouth beaches between Boscombe Pier and Double Dykes – 600,000 m³

Project funding

The estimated £5 million cost for beach renourishment was funded by the government Department for Environment, Food and Rural Affairs (Defra). PHC funded the majority of the dredging project, with Defra paying a proportion of the cost of dredging the sand used for renourishment.

The saving made by utilising locally dredged sand for beach renourishment is estimated to be between £8 million and £15 million.

Environmental considerations

Poole Harbour is internationally recognised as a sensitive environment in terms of wildlife, geology and landscape. It is also important for recreational boating and supports a significant fishing industry.

In view of this, and in accordance with the Harbour Works Regulations 1999, a full Environmental Impact Assessment (EIA) was carried out by Posford Haskoning on behalf of Poole Harbour Commissioners and the local authorities. The EIA study and other extensive assessments of the likely effects of the channel deepening on, for instance, habitats, archaeology and water quality, resulted in one of the most significant investigations ever undertaken into the morphology of Poole Harbour.