Report on Minor Irrigation Works in Madras State

Abstract

Madras State comprises 13 administrative districts with an area of 50,334 square miles. Maximum rainfall is of the order of about 75' and occurs only in Nilgiri District with an area of 989 square miles. In the rest of the State, the rainfall ranges from a maximum of 47 inches to a minimum of 30 inches (occurring in the Tirunelveli District). As the Western Ghats over-shadow the South West Monsoon, contribution of this Monsoon to total rainfall is comparatively low in certain districts. District wise annual rainfall, contribution of North East Monsoon and annual percentages are as follows :— The tract immediately to East of the Ghats for a width of about 40 to 50 miles where the elevation ranges from about 600 to 1500 feet above the sea level, comprises low hills and valleys whereas rest of the area is comparatively Hat with an elevation ranging from 500 to 100 feet in regions closer to the tea coast. Most of the rivers flowing through the State have their sources in the neighbouring State of Mysore. A large number of works had been constructed in both the States along the river valleys several centuries ago. The utilisation was restricted to the construction of tanks and anicuts and channels to a maximum extent with the limited resources available at that time.