Remote Sensing and GIS application in delineation and management of wastelands in Indira Gandhi Nahar Project (IGNP) command area
Spatial distribution and characteristics of wastelands
The statistics generated through spatial data base created in GIS reveal that out of the total geographical area of the district 3.69 per cent or 35816.92 ha has been found under six different wastelands (Balak Ram,1999). Waterlogged and marshy land constitutes 1.12 per cent, land affected by salinity/alkalinity 0.09 per cent, under utilised degraded notified forest area 0.06 per cent, degraded pasture/grazing land 1.14 per cent, desertic sand 1.26 per cent and mining waste 0.02 per cent, respectively (Table 1 and Fig. 1). In general, the waterlogged area, salt affected land and degraded forest are concentrated in canal irrigated northern part of the district. On the other hand the desertic sand, degraded pastures and mining waste areas are occurring in rainfed zone which is concentrated in southern part of the district.
Waterlogged and Marshy Land
This wasteland category constitutes 10851 ha or 1.12 per cent of the total geographical area of the district and 30.30 per cent of the total wastelands area. Waterlogging problem has caused due to excessive irrigation, seepage from canals and lack of drainage. These factors resulted into the rise of water table, then development of salinity and finally the submergence of the land. Resultantly the irrigated double cropped area has gone out of cultivation and planted trees of eucalyptus and Acacia nilotica are dried up. Such wasteland clearly appear in dark blue to light blue colour on satellite imagery. The extent of actual submerged area varies from season to season and year to year. Interpretation of satellite data reveal that the extent of water submerged area is more in rabi season as compared to kharif season probably due to intake of more water for rabi crops. Along the IGNP main canal waterlogged areas are developed around Bashir and Sarni (along Fatehpur distributary), NE and south of Tibi, Silwala Khurd, Masitawali Headwork, Mirjawali, Dabli Khurd, Dabli Kalan, Ranjitpura, Mehrwala, 12 DBL, 14 DBL, 5 DBL, Sukhchainpura, north and SW of Mohanmagariya, NE of Lakhuwali, Naiyanwali Dhani, Khet-ki-Dhani and throughout main canal upto Jesabhatti. Dabli Khurd and Dabli Kalan are the worst affected villages whose 80 per cent settlements are abandoned and people have moved to nearby upland areas. Along the Ghaggar Diversion Canal, waterlogged areas occurs SW of Salemgarh, Chak 1 KSP and 2 KSP, Mainawali, Dhani Karala, Bharusari and Khedasari. The second worst affected area due to waterlogging is developed like a river channel right from Saramsar and Manaktheri in the west to Gandheli in the south east covering nearly 60 km distance. Near Manaktheri and Baropal the width of waterlogged area is 3 to 2 km. Major part of the village settlements of Manaktheri and Baropal are deserted and people are moved in nearby upland places. From here this waterlogged zone passes through Jakhranwali, Khedasari, Bharusari, Dhani Karala, Khet-ki-Dhani, Rawatsar, Nayagaon, Chaiya, Kanwani, and Dasuwali and ultimately reached upto Gandheli village. As a result of submergence Dasuwali and Gandheli settlements are deserted and people moved to nearby upland areas.. These lands are infested with Typha angustata, Arundo donex and Phragmitis spp.. The water table rises at the rate from 0.3 to 0.8 m annually which bring more area under submergence.
Land Affected by Salinity/Alkalinity
This wasteland class constitutes 942.41 ha or 0.09 per cent of the total geographical area of the district and 2.63 per cent of the total wasteland area. These salt affected lands appear dull white and bluish white to white on the imagery. These are secondary salinised land caused due to excessive irrigation, rise of water table, presence of inherent salinity in alluvium, in pockets thick zone of lime/ gypsiferous material in sub strata and lack of adequate drainage. As such the EC value of such soils ranges from 2.00 to 33.0 dSm-1. Salt affected lands are generally occurring around waterlogged areas and around the main waterlogged stretch from Saramsar and Manaktheri in west to Gandheli in the south east which passes through Baropal, Jakhranwali, Khedasari, Bharusari, Khet-ki-Dhani, Rawatsar, Nayagaon, Chaiya, Kanwani and Dasuwali villages. These are also occurring along the IGNP main canal and Ghaggar Diversion Canal and also around Chak 2 KSP, 4 KSP, Pir Kamariya, south of Tibi, Bashir, along Fatehpura distributory, Masitawali, Dabli Khurd, Dabli Kalan, 12 DBC, 5 DBC, 14 DBC, Ranjitpura and Dhani Karala, Lakhuwali, Chohlanwali and Jorawarpura villages. Besides such wastelands are also encountered around Chak 1 MSW, 2 MSW, 3 AG, 654 RD, 1 TLW, 4 RWS and 5 RWS. Changes in cropping pattern i.e. from cotton and wheat to paddy and thereafter no crop, sharp decline in productivity, extinction of native species and degradation of micro-environment are major impact of this phenomenon. Not only such lands are in immediate threat to be engulfed by waterlogging. Therefore, it is very much essential to save these lands from further degradation.