The Neyyar Irrigation Project, one of the commissioned Major Irrigation Projects in Kerala, aims at the harvesting of the Neyyar river for the purpose of irrigation.  This was the first major irrigation project taken up in the Travancore Cochin state under the Ist Five Year Plan.  

The dam was constructed across Neyyar River at Chempilamodu near Kattakkada in Thiruvananthapuram district, approximately 29 kilometres east of Thiruvananthapuram City.   The construction of the project was started in 1951 and completed in 1973.  The project has  Gross Command Area (GCA) of 18095 Ha.  The Project has now become an integral part of the lives of the people of Neyyatinkara Taluk and its surroundings, since it is the main source of water for agricultural and drinking purpose. 

This project consists of (1) Straight gravity rubble masonry dam of 56m height across Neyyar river, (2)  a reservoir having water spread area of 9.1 sq km at Full Reservoir Level and (3) water distribution system consisting of two main canals and its branch canals and distribution planned to irrigate two crops of paddy in the area of 15380 ha.  The canal network consists of  Right bank canal of length  33.4 km, left bank canal of length 33.82 km and branch canals of length 277.78 km.