Man-Made disaster-a case study of Nalco Ash-Pond in The Angul District, Orissa using remote sensing and GIS technique

The breaching of the NALCO Ash-pond in the midnight of December 31, 2000 had caused a serious havoc in 26 villages of the Angul and the Talcher Tahasils of Angul district in Orissa. The Nandira Jhor, a tributary of the Brahmani river flowing adjacent to the pond carried ash to the Brahmani river and its effect was noticed up to 50 km downstream of the river. A study was immediately taken up to assess and evaluate the extent of affected areas using high resolution optical data IRS-ID(PAN) and IRS-ID LISS III of period January 6, 2001. The cadastral maps covering 14 villages of the Talcher Tahasil and 12 villages of the Angul Tahasil were scanned and complete mosaic of 26 villages was prepared. The village layer map was superimposed on the merged data (IRS-ID LISS III+PAN) product at scale 1:8000 and the affected areas were identified village-wise. The final map was immediately handed over to the NALCO authorities for initiation of relief measures. The landuse/ land cover map of pre-breaching (IRS-ID LISS III December 12,2000) and post-breaching (IRS-ID LISS III January 6, 2001) periods were prepared and the spatial extent of different landuse/ land cover class for two dates data were calculated village-wise separately. It was revealed that most of the agricultural lands, land with or without scrub, fallow areas were fully submerged with water mixed with ash. It is seen that villages namely Dighi, Gurujanguli, Nuagoan, Khamana of the Talcher Tahasil and the villages namely Tetoi, Tentolei, Balaramprasad of the Angul Tahasil were seriously affected with high rate of ash deposits.