LAND CAPABILITY STUDIES OF RAMGANGA BASIN USING REMOTE SENSING TECHNIQUES

Abstract

The ever increasing demands for food is gaining utmost importance in the world scene today. This is to be achieved by intensification of food production ,bringing new lands into cultivation and better utilization of grass lands and forests. Thus evaluation and better utilization of land resources gains utmost importance in the present context. Soil and land resources inventory and their proper utilisation is important for scientific and economic plan—fling. These being valuable, but limited natural resources, their scientific management and judicious utilisation for sustained production is essential and should be followed through suitable conservation planning. Using land accord-ing to its needs is the basic principle of such planning. The knowledge of land capability classification, therefore, is pre—requisite and important for planning, implementation and execution of the land resources programme planning. Land capability indicates the most intensive, profitable and safe use of land. Manipulations of plant communities to meet the land based human need is the most efficacious soil protection measure on all classes of lands. Land resources and land use planning comprise of soil survey and land evaluation, assessment of soil degra -n dation, assessment of land use potential, planning of optimal land use besides so many approaches. Conveotional 11 carrying out slope analysis of the contour map drawn from the toposheets. By using available geological information from a preliminary Geological Map of estern Kumaon Himalayas a rock class map of the area has been prepared. The land use map has been prepared by visual interpretation on band-5 of 1:250,000 (blow up from 1:1 million) scale. The three maps have been overlaid, one over the other and with the help of a scoring system developed for the purpose, capability classes have been made for the'Afforestation and Agricultural' uses of the land. A drainage map has also been prepared from the imagery, and the drainage density and drainage frequency have been cor-related with the mean hazard values to ascertain the relation, if any, between them. Besides, Hypsometric analysis of the basin has also been carried to assess the degree of its maturity. Lastly a digital mapping of the study area has been attempted on the basis of the available erosion bazard values from the erosion hazard. map prepared from super-imposition of relief, rock—class's and land use of the study area. The results obtained are: (1) Only 5 percent area in the basin is highly proble-matic and needs top priority for development of additional forestry, whereas (somewhat lesser pro-blematic 18 ) area may subsequently need afforests- tion. Besides, some of the area (77•.) can be put under agricultural use. Vt field studies cannot cope with the demands of time for collection of data on the aforesaid parameters at National level. Aerial photography since forty's and landsat data from seventy's have opened new vistas of knowledge in abstracting information of soil and land resources for evaluating their potential and efficient utilisation. Re -mote sensing offers an efficient approach for mapping the present land use and to monitor the changes over time as LANDSAT gives the unbiased data of the same area with 18 days interval-. The landsat M.s.S. data are more amenable for computer processing because it is available in digital format. With this aim in view, the present study has been attempted at to develop a land capability classification for afforestation and agriculture in the upper Ramganga basin. In carrying out this study LANDSAT imagery (in band-5) of 1:1 million scale, in conjunction with aerial photographs and topographical maps has been analysed to get land use and vegetal cover classification in the following categories (i) Thick (dense) forests (ii) Thin forests/ Bushes and Shrubs (iii) Cultivated/Grass lands (iv) Barren lands/Sandy/Open lands. The study area has an extent of 3086 sq.kms and lies between latitude 29° 30 to 300 10 North and longitude 780 35 to 79 35 East. In this study, the 'Capability classes for specified uses' have been considered. For this purpose, three factors namely, relief classes, rock—classes and land use have been taken. A relief classification map has been prepared by (ii) Drainage density and drainage frequency have been found to have sleak correlation with the mean erosion hazard values of the basin. Mean erosion hazard value has been taken as a function of relief, rock—classes and land use of the study area. (iii) The hyposometric analysis of the Ramganga basin indicates that it is still in the youthful stage of equilibrium and that active erosion in the basin is likely to pose problems. (iv) Digital analysis of the basin has provided close confirmation of the erosion hazard map prepared through manual approach. The above study has demonstrated the viability of remote sensing techniques in carrying out the land- capa-bility studies of mountainous watersheds.