This document discusses the Vembanad Lake, the largest backwater lake in Kerala. It is fed by five rivers and lies partially below sea level, causing salinity issues that damage agriculture and limit drinking water. The document outlines the traditional practices of rice cultivation in the region, including using specific seed varieties, water wheels, and worm baskets. It also describes the transportation of goods by canoe and fishing of various species. The document notes some current environmental issues facing the lake, such as the use of chemicals and the spread of invasive weeds, and how the construction of a bund has affected water flow and prawn populations.