Current General Studies Magazine (August 2014)
General Studies - I (Geography Based Article)
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
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. 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”.
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.
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.
The Atlas reports that India has an unbelievable number of
11,740 lakes that are natural, with a water spread constituting an area of 7.3
lakh ha. Since there is lack of basic appreciation of what is man-made and
natural in this exercise, the purpose of classification has gotten defeated.
Hence, the first level of classification may not be useful for explaining the
role of humans in creating and sustaining the wetlands.
Further, the Atlas also suggests the existence of an
additional classification called small wetlands (less than 2.25 ha) numbering
around 5.6 lakhs with an estimated area of 5.6 lakh ha. It is not known whether
these are treated as man-made or natural. In all probability many of these would
be man-made, with a very few being natural.
Definitional problems and anomalies exist in defining lakes
and ponds around the world, and across the disciplines dealing with the study of
wetlands. However, in the Indian context, distinguishing lakes and tanks should
not be an issue, Well-established documentation is available with the
irrigation and revenue departments in many of these states. The Atlas defines
natural lakes as “Larger bodies of standing water occupying distinct basins
(Reid et al, 1976). These wetlands occur in natural depressions and normally
fed by streams/ rivers”; and a man-made tank/pond as “an artificial pond, pool
or lake formed by building a mud wall across the valley of a small stream to
retain the monsoon (Margarate et al, 1974).” These definitions are inadequate
Lakes and tanks are both formed in naturally occurring
depressions, but what differentiates them being natural or artificial is the
ability to facilitate a gravity flow to receive and discharge water. Lakes and
tanks might both have their defined basins. They also might be fed by rivers,
streams and canals. But, the differentiation lies in how they are fed with
water. Most of the naturally occurring lakes get water from the naturally
formed channels, but all tanks get water from trained rivers or channels. Lakes
may or may not have an embankment on their boundaries, but tanks certainly
will have an embankment to divide the water spread with the command area. Many
large tanks draw water directly from rivers as well. For example, Veeranam tank
in Tamil Nadu draws water from the mighty river Cauvery directly through a
channel that is partly man-made and partly natural, and the river Vaigai ends up
in a large man-made tank called Ramanathapuram Big Tank, leaving a small stream
of the river touching the Indian Ocean.
Define wetland according to Ramsar convention.
What is the purpose of natural and manmade classification of wetland?