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Publisher Summary This chapter deals with tidal energy. There are two fundamentally different approaches to exploiting tidal energy. The first is to exploit the cyclic rise and fall of the sea level using barrages and the second is to harness local tidal currents in a manner somewhat analogous to wind power. Many industrial, commercial, and public bodies have suggested that there is a high degree of synergy between the development of a tidal current generation industry and the offshore oil and gas industry. This offers the intriguing prospect of a new renewable industry developing in partnership with the petroleum industry and could, perhaps, result in accelerated development, as a result of the availability of expertise and technology, which would otherwise have to be developed from scratch. However, the high capital costs associated with tidal barrage systems are likely to restrict development of this resource in the near future. Tidal current systems may not presently have the strategic potential of barrage systems but, in the short term at least, they do offer opportunities for supplying energy in rural coastal and island communities.

Publisher Summary This chapter discusses the tidal dynamics in the muddy coastal environments of Jiangsu and the Wash. Tidal waves in the open sea are normally progressive waves that have their maximum tidal currents occurring at high and low tides. It is found that when they approach shallow coastal waters, the reflection of the progressive tidal wave may result in a standing tidal wave. This is associated with a maximum tidal flow rate at mid-tide. Such changes in the type of tidal wave and the occurrence of the maximum tidal current velocities may strongly influence the sediment dynamics of muddy coasts. A study undertaken over the intertidal flats and saltmarshes within the Wash has shown that the ratio of the flood tidal duration to that of the ebb is between 0.66 over the lower part of the intertidal sandflat,and 0.9–1.0 over the saltmarsh. Tidal ranges can affect the prevailing tidal dynamics of a muddy coast in a variety of ways. It is found that the tidal current curves change gradually from sinusoidal in offshore water into a cosinusoidal or trochoidal form over most of the intertidal area above the mean tidal level.

An approach to the method for the calculation of gravitational oceanic tidal load is made. The results obtained by employing three different cotidal charts (M2) are compared. They give a map for the geographic distribution of the component of gravitational tidal load (M2) for the BTTZ area and the inland of China together with a tidal map of K1.

The Severn estuary is a high-energy tidal regime with strong residuals generated by nonlinear effects. The present knowledge of the tidal and residual flow is reviewed. Some measurements of current profiles were used to calculate the M2 tidal parameters and a residual flow and also the friction stress through depth at a particular location. A 3–dimensional (3-D) model of the inner Bristol Channel and Severn Estuary was used to generate tidal and residual currents in the area and these are compared with the available observations.