Photo 1 (Return)

Hengistbury Head and Christchurch Harbour, August 1998. Hengistbury Head (1) forms a boundary between Poole Bay (to left) and Christchurch Bay (to right). The Long Groyne at the headland is outflanked by eastward drift of sand (orange arrows) that enters Christchurch Bay and contributes to Mudeford Spit (2), which has deflected the harbour inlet channel to the northeast. The corresponding Haven House Spit (3) has grown southwards. Sediments entering the inlet are flushed seawards by dominant ebb tidal currents and accumulate within an ebb tidal delta (4). Waves drive sands northeastward from the delta to the shore where drift continues to the northeast (see accumulations against groynes). Some sand is driven into the harbour, where it accumulates as a distinct flood tidal delta (5) and contributes to sandy tidal flats (6). Significant freshwater flows from the Stour and Avon rivers (8) introduce suspended sediments. Together with marine suspended sediments that enter the inlet, these materials have accreted for several thousand years forming Stanpit Marsh (7). Mudeford Spit has a history of extension and erosion/breaching in response to updrift sediment supply.