Norfolk

Norfolk meets the North Sea on a low, wide, vulnerable coast — sand dunes, salt marshes, shingle bars, and river mouths rather than cliffs. The tidal regime is mesotidal North Sea: mean spring range along the Norfolk coast runs from around 1.8 metres at Cromer in the north to 2.0 metres at Great Yarmouth in the south. Two tides a day, six-hour cycles, semidiurnal and broadly regular. That is nowhere near the Bristol Channel extremes, but on a coastline this flat it is enough to transform the landscape at every tide. The mud and sandflats exposed at low water at Brancaster, Blakeney Point, and Scolt Head Island are among the largest intertidal areas in England, and the spring tides that push highest give the salt marsh and dune systems the inundation they need to maintain their ecology. Blakeney Point, managed by the National Trust, holds one of England's largest grey seal colonies — 3,000-plus animals hauling out on the shingle point. The pup counts are highest between November and January, and the viewing boats from Morston Quay run their schedules around the tidal window in Blakeney Harbour channel. The harbours along the north Norfolk coast — Wells-next-the-Sea, Blakeney, Morston, Brancaster Staithe — are tidal harbours: accessible from the sea only around high water, drying to mud or sand for much of the low-tide period. The fishing boats and pleasure craft all work their schedules around the tide. On the east coast at Great Yarmouth, the River Yare meets the sea through Breydon Water, a broad tidal estuary that sits immediately behind the town — a nationally important site for wintering wildfowl and breeding waders, SSSI-designated and flanked by the Norfolk Broads, the largest protected wetland in Britain. Tidal bores occasionally form on the Yare as spring flood tides push upstream, and the salinity gradient in the estuary shifts significantly with the tidal state, shaping what species are present and where. The Environment Agency maintains tide gauges at Great Yarmouth and Cromer; the UKHO publishes the official Admiralty tide tables for the Norfolk coast.