Abstract

About 87,000 acres of Pollachi taluk of the Coimbatore district is to be brought under canal irrigation under the proposed Parambikulam-Upper Aliyar Project. This area is to be benefited partly by the Upper Canal, Sethumadai canal and Aliyar feeder canal and partly by the Pollachi canal. This area now is either well irrigated or dry depending upon the availability of water in the wells. The water table is fairly high in this area and the cropping pattern is changed to suit the varied nature of the well waters. The main crops for which the water is utilised at present are groundnut, chillies, brinjal, cotton and coconut. In the area, the cropping pattern is likely to be changed by the coming in of the irrigation water in the canals fed by the Parambikulam dam due to the availability of abundant water and also due to the possibility of the quality of water being changed due to the coming in of the water from the Parambikulam area. Since in most of the areas, there is only a limited choice of irrigation water now, the cultivators at present have to make the best use of the available water whatever may be the quality of the same. As the utilisation of the low quality waters for irrigation will result in the deterioration of the land, it is imperative on the part of the cultivators to understand the nature of the available water and modify the cropping pattern. In addition to this the quality of water in wells and streams changes appreciably with the season of the year and also with the distance down from the streams or canals. In addition to this the water table of the ground waters and soils will also be influenced by the fluctuations in the canal water level and also by the quality of water flowing in the canals. As such it is a necessity on the part of soil scientists now, in view of the proposed Parambikulam Aliyar project whose canals pass through this district, to prevent any hazard to the land due to the coming in of the irrigation facilities in this project area. For the above purpose it is necessary to study the quality of the ground water prior to the coming in of the water in the canals and also after the canals have been commissioned. With the above purpose in view, the present study of the quality of the ground water was taken up.

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