Only in the exceptional circumstances of a narrow, steep-sided site for a barrage would the 'working' components of a barrage, namely the turbines in their power house, the sluices and the ship lock, occupy the full width of the estuary. The remaining gaps would have to be closed by embankments or plain, i.e. non working, caissons. This chapter considers both options. Except where access from one bank of the estuary has to be provided early in the construction programme, the non-working parts are the least cost items and should be least sensitive to tidal currents during construction. Thus they would normally be built when the expensive turbine caissons and sluices had been placed. This aspect, loosely referred to as the 'closure' of the estuary, is discussed in Chapter 8.

Inspec keywords: offshore installations; dams; tidal power stations; hydraulic turbines

Other keywords: power house; construction programme; turbines; barrage; ship lock; sluices; plain caissons

Subjects: Tidal power stations and plants