ABSTRACT
Water-logging, high salinity levels and poor drainage in agricultural lands are believed to be the primary reasons for the collapse of many earlier civilizations. Indiscriminate and excessive use of water results in bringing the water table to the surface. This also brings salts present in the soil to the surface, thereby creating saline and alkaline conditions. It is believed that about 8 × 106 hectares of land is affected by salinity and alkalinity conditions in India including the coastal regions which are subject to periodical inundation. Of these, about 5 million hectares constitute noncoastal regions and the balance 3 million hectares are in the coastal regions. The statewise breakdown of the two components are roughly as follows:
11.2 CAUSES OF WATER-LOGGING PROBLEM Development of modern civilization, resulting in a network of railways, embankments and canals running across the country and expansion of inhabitation with population growth has very seriously affected the natural runoff conditions of ground over vast areas of the country. The principal factors that contribute to water-logging in noncoastal areas are continuous rainfall, seepage, flooding of rivers, over-irrigation, faulty crop rotation, and blocking of natural drainage systems. In the case of coastal regions the problem areas are concentrated mainly at the confluence of rivers with seas which are essentially lowlying areas. They are subject to inundation by tidal waters and the inland drainage water almost simultaneously and regularly. Generally speaking, the deltas of the eastern coast are low-lying with marshy lands of the Sunderbans in the north and natural lakes like Chilka, Kolleru and Pulikat along the coast. In the case of the western side the coast of Kerala and Valsad and Surat districts of Gujarat are low-lying. The causes of water-logging, the different aspects of its management, the various degrees of relief possible and the reclamation problems associated with it are all briefly dealt with in Fig. 11.1.
