Ecological studies in the Ukai command area

Abstract

Abstract The present study was directed towards studying the impact of the Ukai-Kakrapar irrigation project on the ecology of the command area with particular reference to changes in cropping pattern and land degradation due to waterlogging/salinity. The data used were multitemporal (1972-1981) LANDSAT imagery of the entire command area, multitemporai colour infrared plus black-and-white aerial photography and multispectral scanner data over a test area of about 1200 km2 collected from November 1980 to February 1982. Land-use maps for the entire command area at 1:250 000 scale (LANDSAT) and land-use/cropping-pattern maps for the test area at 1:12 500 scale (aerial photography) have been prepared. The results indicate that due to the introduction of large-scale irrigation, the cropping pattern has changed and the acreage under heavy perennial crops such as sugar-cane and banana has increased beyond permissible limits resulting in a rapid rise in the water-table in the area. The areas delineated as waterlogged and salt-affected from the aerial and LANDSAT imagery, when correlated with the subsoil water-table data, were found to have the water-table within 0-1 5 to 1-5-3-0 m.