(Sample Material) IAS Mains GS Online Coaching : Paper 1 - "Salient Features of World Physical Geography "

Sample Material of Our IAS Mains GS Online Coaching Programme

Subject: General Studies (Paper 1 - Indian Heritage and Culture, History & Geography of the World & Society)

Topic: Salient Features of World Physical Geography

Salient Features of World Physical Geography

National Wetland Atlas of India: A Review and Some Inferences

The National Wetland Atlas 20111 (hereafter the Atlas) had the ob­jective to map all types of wet­lands and to become a national database by bringing out state-wise detailed publi­cations. The Atlas, apart from producing the maps, estimated the area, vegetation and turbidity levels of wetlands. The Atlas project used satellite images from the Linear Imaging Self-scanning Sensors-m (liss-iii) with a resolution of 23 metres and thereby able to view water bodies up to a size of 529 square metres. The project was led by the Space Applications Centre (sac) of the Indian Space Re­search Organisation (isro), and 25 other specialist institutions undertook the pro­ject in their respective states.

Though the Atlas is an earnest effort to use the ad­vancements in earth observation tech­nologies such as the remote sensing and geographic information system (gis) tools, it is riddled with definitional prob­lems, inconsistency of method and a poor understanding of Indian wetlands. The review highlights some of these is­sues affecting “man-made tanks and ponds”, which constitute the largest chunk of the Indian wetlands.

This detail has to be understood against the 1992-93 estimate of total Indian wet­lands as 8.26 Mha (million hectares). Even accepting the fact that the Atlas in 2011 used a better and smaller scale compared to the previous ones, it is very difficult to believe the variations in the estimates. In the intervening three dec­ades, many wetlands are said to have shrunk rather than having increased. Some amount of analysis of larger-sized tank wetlands, if done, would have giv­en a better picture of what is happening, rather than showing an increase in the wetland area.

Confusing Classifications

The Ramsar Convention3 defines wet­lands as “areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres”.

Based on this, A Di­rectory of Asian Wetlands (Woistencroft, Hussain and Varshney 1989) classified all of Indian wetlands into eight classes.

These included

(1) The tanks and reservoirs of the Deccan plateau together with the lagoons;
(2) The vast saline expanses of Rajas­than, Gujarat and the Gulf of Kutch;
(3) The freshwater lakes and reservoirs from Gujarat eastwards through Rajas­than and Madhya Pradesh;
(4) The deltaic wetlands and lagoons of India’s east coast;
(5) The marshes, jheels, terai swamps and chaur lands of the Gangetic Plain;
(6) The flood plain of the Brahmaputra and the marshes and swamps in the hills of north-east India and the Himalayan foothills;
(7) The lakes and rivers of the montane (primarily Palearctic) region of Kashmir and Ladakh;
(8) The wetlands (primarily mangrove associations) of India’s island arcs.

This classification is simple, straight­ forward and has regional specificity. However, the Atlas used a three-level hierarchical classification without any regional specificity. Level 1 classified the wetlands as inland or coastal; Level 11 further divided them into natural or man-made; and Level m grouped all wetlands into 19 different classes.5 Since India is a land of continental proportions with substantial variations in its tracts, regional specificity is very important.

Natural vs Man-made classification

The purpose of the natural and man-made classification is to evoke an inter­est in and monitor these wetlands. India is known for developing water sources aimed at serving agriculture, fishery and other domestic and cultural uses. For example, man-made tanks offer many uses and services and every tank has some history. By way of their engi­neering and design, all tanks deliver wa­ter to the fields through gravity. Further, these man-made tanks are part of a large number of inland bird sanctuaries in south India, and are home to hundreds of species of fishes and plants. They have been functioning with little or no modifi­cation for centuries and seem to be “natu­ral”. Unfortunately, even in India, many among the scientists are not aware of this fact. The researchers of this Atlas seem to be no exception. It appears from the methods used and the results arrived at that the study presumed that many hundreds of these ancient man-made systems were natural lakes.

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