Tides at a coast

People often experience tidal influence at the coast, where the sea meets the land, with a daily or twice-daily rise and fall of the water level. Understanding and predicting tides is critical for: shoreline/hazard management; port, harbor, and shipping activities; renewable energy; and infrastructure management (e.g., telecommunication cables). Accurate prediction is also critical to ensure water sports and beach activities are carried out safely. In shallow waters, tides interact with bathymetry and other physical processes, such as: surges, waves, and density currents. Understanding the net (tidally averaged or residual) flow is key to explaining the transport of particulate and dissolved biogeochemical tracers and physical properties, such as heat and carbon. To observe the tide, (global) gage networks are installed, often providing near real-time data. Harmonic analysis of these data allows accurate prediction of the tide to support the numerous recreational and commercial activities that take place in shelf seas and at the coast.