The Vembanad lake, the most important of the west coast canal system has a length of 84 Km and an average breadth of 3.1 Km. It covers an area of 204 Sq.Km. Stretching from Alappuzha to Kochi. Borders Cherthala, Ambalapuzha and Kuttanad Taluks of Alappuzha district, Kottayam, vaikom and Changanasserry taluks of Kottayam district and Kochi and Kanayannur Taluks of Ernakulam district. Pamba, Achankovil , Manimala, Meenachil and Muvattupuzha rivers discharge into this lake. Pathiramanal, often called the mysterious sand of midnight, having coconut palms and luxuriant vegetation is situated in the centre of this lake. Perumbalam and Pallippuram are the other islands in this lake. The Thannermukkom regulator constructed across Vembanad lake between Thannermukkom and Vechur is intended to prevent tidal action and intrusion of saline water into the lake. It is the largest mud regulator in India.