All that movement of water generates a lot of energy, and one way to harness that energy is by building a structure called a barrage there.
A barrage is basically a large low dam that’s built across an estuary.
When the tides go in and out, the moving water flows through tunnels in the barrage.
So you have huge amounts of water trying to flow through these relatively small tunnels and that turns turbines that generate electricity.
Now, these estuaries are important because of their high level of biological productivity, they are home to lots of birds, fish and other marine life.
So when you propose to construct a barrage, you have lots of issues to consider, for example, it would change the existing water levels in the estuary.
Since a lot of water is getting held up by the barrage, the incoming tides won’t go as high, but they wouldn’t be as low during low tide, either.
This might help prevent flooding, but it would also affect the mudflats.
Those areas of mud that normally are exposed when the tide recedes.
But don’t lots of birds rely on exposed mudflats for food? I mean don’t they eat tiny animals that live in the mud?
And what about those tiny animals? What would happen to them if the mudflats were endangered?
So you are seeing some of the potential problems with the barrage.
But consider this, right now, the water in an estuary is very cloudy.
The tidal currents are constantly churning up the sediments that rivers deposit in the estuary.