South Holland

South Holland (Zuid-Holland) is the western Dutch province that fronts the southern North Sea, with Rotterdam at its centre, Scheveningen at The Hague's beach, the long Hook of Holland sand-and-dune coast running south to the Maasvlakte, and the Delta Works dam network at the southern edge. The tide here runs the southern North Sea signature: cleanly semidiurnal, two highs and two lows of comparable size each day, twelve and a half hours apart. Mean range at Hoek van Holland is about 1.7 metres, climbing past 2.0 metres on spring tides and dropping near 1.2 on neaps. Inside Rotterdam Europoort the propagating tide reaches the harbour about 30 to 60 minutes behind the open coast at Hoek van Holland, with the working pilots on the New Waterway timing approaches by the slack on the rising flood. The country's open coast is mostly long sand and dune broken by the engineered openings at the IJmuiden lock, the Scheveningen harbour, and the Hook of Holland river mouth; the rest is hard sea defences engineered after the 1953 North Sea flood that overtopped the southern Delta. The Delta Works themselves include the Maeslantkering storm-surge barrier across the New Waterway, designed to close when forecast water levels exceed 3 metres above NAP at Hoek van Holland and Dordrecht. Rijkswaterstaat runs the authoritative gauge network and publishes the official tide tables. Open-Meteo Marine drives the gridded predictions on this site; for piloting the New Waterway and the Wadden coast the Dutch hydrographic service is the authoritative source.