Water Management for Irrigation in Kerala
Despite Kerala's bounty of natural wealth, the state finds itself increasingly under pressure in the two vital resources of land and water. Efficiency in their use is, therefore, very important.
Traditionally, the crop choice of the farmers in Kerala had a strong association with the physiographic nature of the land they cultivate and the suitability of the crop to the land. The water rich valleys (0 - 7.5 m altitude) were earmarked for moisture loving, submergence tolerant crops like paddy, sugar cane, etc. In the lower slopes (of 7.5-75.0 m altitude), where the water table is fairly high, but the soil is drained, annual/ seasonal crops like tapioca, plantains, vegetables, etc. and perennial crops like coconuts, rubber, pepper, cashew, arecanut, etc, are preferred. The perennial cash crops of tea, coffee (Robusta variety), pepper and even coconuts, rubber, etc, dominate the high land (75-1,000 m) regions. Hogh ranges (700-1,500 m) are devoted to crops like cardamom, coffee (Arabia) and tea (GOK 1998; GOK 2003; Rao 2003). Land utilisation in Kerala has undergone drastic changes, as much of the land hitherto engaged for water intensive foodgrain production has been either converted to suit human needs other than cultivation or is increasingly employed for crops demanding less water. This must have a direct repercussion on the intensity of water use for agriculture. A vast pool of the state's scarce financial resources is being used for improving irrigation. It is reported that the state has already (up to the Tenth Plan) spent more than Rs. 38 billion on irrigation, flood control, command area development (CAD) and anit sea erosion (GOK 2003; GOK 2007). A large chunk about 70%) of this sum had been allocated exclusively to major (with cultivable command area greater than 10,000 hectares) and medium (with command area greater than 2,000 hectares) irrigation systems.
This paper seeks primarily to assess the water resources of the state and the total water requirement of crops. It them examines critically, with the continuing shift of crop area in favour of cash crops, if the strategy of pumping more funds into the irrigation sector still stands to reason. The subject of the paper is confined to the water needs of only agriculture.
The paper is organised into four sections. Section 1 is an appraisal of the water resources of the state. The cropping pattern in the state practised over different periods has been analysed in Section 2. Assessment of the water requirement of various crops cultivated in Kerala, across the Plan periods since 1980-81, is made in Section 3. Section 4 seeks to ascertain, in the light of the changed cropping pattern, whether the irrigation infrastructure built up over the years yielded returns, especially with regard to the financial efficiency parameters. The study relies solely on secondary data available from various government agencies.