2.2.6. Importance of Tides

Since tides are caused by the earth-moon-sun positions which are known accurately, the tides can be predicted well in advance. This helps the navigators and fishermen plan their activities. Some of the important activities associated with tides are:

1. Tidal flows are of great importance in navigation. Tidal heights are very important, especially harbours near rivers and within estuaries having shallow ‘bars’ at the entrance, which prevent ships and boats from entering into the harbour. Large ships enter the harbour of a shallow sea during high tide and they go back also at the time of high tide. London and I have become important ports due to the tidal nature of the mouths of the Thames and Hugli rivers respectively.

2. The river mouths and estuaries are kept clean of sedimentation due to the action of tidal currents. The force of the outgoing tide and the river current carries the silt away to the open sea. This helps in navigation.

3. The tidal force can also be used as a source for generating electricity. A 3 MW tidal power project at Durgaduani in Sunderbans of West Bengal is under way.

4. The inflow of the salty tidal water, especially along the coast of cold countries, retards the process of freezing and prevents the harbours from becoming ice-bound.

5. The fishing industry is helped by the rhythm of high and low tides. The fishermen mostly sail out to the open sea during low tides and return to the coast at high tides.