There are 34 backwaters in Kerala. Out of it, 27 are located either closer to Arabian Sea or parallel to the sea. The remaining 7 are inland navigation routes.

The backwaters have a unique ecosystem: Freshwater from the rivers meets the seawater from the Arabian Sea. A barrage has been built near Thanneermukkom, so salt water from the sea is prevented from entering the deep inside, keeping the fresh water intact. Such