Haor means a marshy wetland ecosystem physically is bowl or saucer shaped depression that looks like inland seas during the monsoon floods. It is seen mainly in Kishoregonj and Sylhet area. Those haor gets flow by river and canal. In the winter it turn into large pasture but in the rainy season it has opposite scenery. It turn into vast tank of water.
Once upon a time this catchment area was consisted by permanent and seasonal lake from Meghna and its branches. Where there were plenty of aquatic plants. But for gradually filling those catchment area lost their depth. There grow up bush of bulrush. So, those places became the ideal place for food and shelter for fish and others aquatic animal. It has become the attractive place for migratory birds. For excretion of birds, this water body grow plenty of Phytoplankton. Which help in eutrophication process.
This catchment area is surrounded with Megaloy mountain in north (India), mountain of Tripura in south (India), High elevation of Munipur in east( India). There are six thousand shallow water tank in this plain silted land. Which is called bill. A large area which is inundated by monsoon flood is circumambient this area. Many Indian hills stream and river which are in nearest places flow water in this land. It goes in 6 meter deep in rainy season by onrush of water. Though much water move away in winter.
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