Estuaries are a natural wonder where rivers or streams flow into the sea. This freshwater-seawater mix makes it one of the most productive habitats in the world.Tucked away between calm backwaters and a lovely beach Estuary Island, situated in Poovar, is like a little secret. It literally starts opening itself up to you as you travel down by boat, revealing itself from among the coconut palms and other greenery that is native to tropical Kerala.