BARRAGE ACROSS MOUTH OF ESTUARY

Barrage across the Mouth of an Estuary

Barrage across the Mouth of An

Introduction

A Tidal Barrage is a Dam built across an Estuary or Bay to generate Electricity from the Flow of Tides. It works using the same principles that is used in production of the mainstream hydro powered electricity. In this form of Tidal Power, a Barrage is built near the coast where water is collected during the periods of high tides. During low tide the barrage allows the water from the reservoir to move towards the ocean or sea (Bell, 2008). The potential energy of the water at a higher level is converted to electricity using Turbines.

Estuaries are semi-enclosed coastal water bodies which have an open connection with the sea but in which sea water is measurably diluted by fresh water; this includes the mouths of most rivers. Each estuary has a unique combination of features derived from its shape, catchment, connection to the sea, tidal régime and exposure. Commonly, estuaries are highly productive, not only producing much new organic matter through the growth of marsh plants, benthic diatoms and phytoplankton but also processing large quantities of dead organic matter (detritus) derived from the marshes and the surrounding catchment (Bell, 2008).

In most cases, arid especially when turbid water reduces the light needed for phytoplankton growth, the fauna is dominated by species that can utilise detritus. This community in turn supports large populations of fish and birds. Some of this move freely between estuaries, creating biological connections between them that may extend over very long distances. Estuaries are also constantly changing, caused by sea level changes and the continuous flux of materials from land and sea. Added to this is the immense variety of human impacts: impoundment, pollution, industrial and residential developments, recreation and other activities in both the estuary and its catchment. Thus, each estuary is an extremely complex system and, in order to evaluate the consequences of human impacts in the past, present and future, the system must be understood as a whole.

In recent decades, barrages have been proposed for many estuaries for tidal power generation, protection against storm-surges, to provide transport, impoundments for recreation and fresh water storage. Some have been built, and these illustrate not only the benefits but also that there is a potential for unexpected ecological effects. Rising public concern for the environment requires all future proposals for estuary modification to be carefully evaluated, with full recognition of the estuary's natural complexity. In the special case of tidal power barrages, it is necessary also to compare the environmental consequences of a barrage with those incurred by other forms of power generation (Orive, 2002).

Environmental impact

Tidal Barrages cause a major disruption to the marine life on the estuary or the bay on which it is built. This is one the major cons of a Tidal Barrage. Fishes frequently get killed in the Turbines of the Tidal Barrage and it also may lead to change in the migration ...