Boskalis Westminster (previously Westminster Dredging Company) have undertaken the maintenance dredging at Harwich for many decades. After a tender process in 2008, the works were again awarded to a joint venture involving Westminster Dredging.
The works are split into two parts with Boskalis Westminster (BWL) as the lead company.
Major Works: Maintenance dredging in the approaches and berth pockets to Felixstowe and Harwich, with disposal of the dredged material at the Inner Gabbard disposal ground. The volume dredged each year is approximately 1,200,000 m³, completed over four or five campaigns throughout the year. Each campaign takes approximately three weeks, with a trailing suction hopper dredger (TSHD) on site for ten to twelve days of each campaign. A TSHD with a carrying capacity between 8,000 m³ and 12,000m³ is the optimum vessel for these major works. A plough vessel, such as the ‘Norma’ is used to bring material from the berth faces to a location that can be accessed by the TSHD and to assist in maintaining Harwich International, Harwich Navyard, Mistley and other port channels and jetties.
Minor Works: These form the Beneficial Sediment Replacement Scheme which controls disposal of dredged material and is intended to feed mobile sediments back into the estuary and river regimes to maintain the natural balance, or sediment budget.The material is generally dredged from the Felixstowe berths and approaches, with disposal at two locations on the River Stour and two on the River Orwell.