Kallada
The River is formed by the three rivers i.e. Kulathupuzha, Chendurni and Kalthuruthy joining together near Parappar. The river has its origin in Papanasam range South of Kulathupuzha in Quilon district of Kerala State at an altitude of 900 m above MSL. The river has a length of 121 km. and drains an area of 1,699 sq.km before confluencing with the Ashtamudi Lake. There is one CWC Hydrological Observation Station at Pattazhy on this river. The Kallada basin experiences good rain fall and humid atmosphere throughout the year. The climate along the coastal of this basin is generally hot with high humidity. The normal daily mean temperature of the basin varies from 26.1°c to 29.1°c. Even-though the monsoon period of the basin is considered from June to Nov, the basin gets most of the rainfall during June to August. The annual rainfall varies from 2225 mm to 4038 mm. The basin experiences moderate and uniform wind velocity through out the year. Generally it varies from 8.5 to 13.6 km/hour as per the I.M.D. data.