196
11.7.12 Jurisdictional Wetlands
The term jurisdictional wetland has been used
for legally defi ned wetlands in the USA since
1989. It was to delineate those areas which are
under the jurisdiction of Section 404 of the Clean
Water Act (CWA).
Later, a report of the National Research
Council (NRC) of the USA (NRC 1995 ) called
for the fulfi lment of an ambitious goal of gaining
four million ha of wetland by the year 2010. This
could be done through the re-conversion of crop
and pasture land. There had been a review of the
scientifi c basis of wetland delineation and classifi cation in another NRC report (NRC 1995 ). It
was done particularly because it was related to
the regulation of wetlands in the USA at that
time.
11.8 Origin and Evolution
of Wetlands
In the cold belt, the process involves receding of
the glaciers; and concomitantly, the debris which
are washed out of the melting ice fi ll the crevices
near the edge of the ice sheet and cover isolated
blocks of melting ice. When these ice blocks
melt, the resulting depressions become isolated
‘kettle lakes’, etc .
In some regions, ponds are formed when
subterranean chambers collapse. Also, many
small ponds may be formed where beavers
build dams. Many lakes and big ponds are
deliberately constructed for reservoirs, meant
for generation of hydroelectric power as well as
for recreational and aesthetic purposes. Further,
many ponds are formed along the highways
when dirt is removed for use in constructing the
bed of the highway.
Some wetlands are small kettle holes; others
are in the last stages of ‘succession’ which is
triggered when aquatic plants produce organic
matter faster than decomposing organisms can
recycle it. The remains of the plant bodies
gradually accumulate until no open water
remains.
Summary
1. Wetlands are important components of the
landscape all over the globe. The wetlands
stand testimony for the growth and propagation of many civilisations in the world. But
modern history of wetlands is shrouded with
some amount of misunderstanding and negligence about them. This has been leading to
their gradual (often fast) damage and dereliction. This has been posing threat to civilisation and ecology with regard to potential
habitat for meeting requirements of nutrition,
avocation, habitation and so on.
2. Wetlands have been regarded as kidneys of the
landscape. It is because they function as the
downstream receivers of water and wastes
from both natural and human sources.
3. Recently, wetlands have become the cause
célèbre for conservation-minded people and
organisations of the world.
4. Wetlands are sometimes diffi cult to defi ne
precisely, not only because of their great geographical extent, but also because of the wide
variety of hydrologic conditions in which they
are found.
5. Wetland science or wetland ecology or telmatology is that branch of science which deals
with a specialised study of the wetlands.
Persons who do such specialised study of wetlands are called wetland scientists or wetland
ecologists or mire ecologists .
6. Our knowledge of different wetland types is,
for the most part, isolated in distinctive literatures and scientifi c subjects. However, there is
an urgent need for a universal defi nition of
wetlands, though it is, sometimes, diffi cult to
get one. The term ‘wetland’ did not come into
common use until the mid-twentieth century.
Precise defi nition of wetland is needed by distinct interest groups, namely,
(a) Wetland scientists and (b) wetland managers and regulators
Nevertheless, some of the scientifi c defi nitions of wetlands are as follows:
1. The term ‘wetland’ refers to lowland covered
with shallow and sometimes temporary water.
2. Wetlands are waterfowl habitats according to
Circular 39.
11 Wetlands in the Landscape: Their History, Defi nitions, Origin and Evolution
11.7.12 Jurisdictional Wetlands
The term jurisdictional wetland has been used
for legally defi ned wetlands in the USA since
1989. It was to delineate those areas which are
under the jurisdiction of Section 404 of the Clean
Water Act (CWA).
Later, a report of the National Research
Council (NRC) of the USA (NRC 1995 ) called
for the fulfi lment of an ambitious goal of gaining
four million ha of wetland by the year 2010. This
could be done through the re-conversion of crop
and pasture land. There had been a review of the
scientifi c basis of wetland delineation and classifi cation in another NRC report (NRC 1995 ). It
was done particularly because it was related to
the regulation of wetlands in the USA at that
time.
11.8 Origin and Evolution
of Wetlands
In the cold belt, the process involves receding of
the glaciers; and concomitantly, the debris which
are washed out of the melting ice fi ll the crevices
near the edge of the ice sheet and cover isolated
blocks of melting ice. When these ice blocks
melt, the resulting depressions become isolated
‘kettle lakes’, etc .
In some regions, ponds are formed when
subterranean chambers collapse. Also, many
small ponds may be formed where beavers
build dams. Many lakes and big ponds are
deliberately constructed for reservoirs, meant
for generation of hydroelectric power as well as
for recreational and aesthetic purposes. Further,
many ponds are formed along the highways
when dirt is removed for use in constructing the
bed of the highway.
Some wetlands are small kettle holes; others
are in the last stages of ‘succession’ which is
triggered when aquatic plants produce organic
matter faster than decomposing organisms can
recycle it. The remains of the plant bodies
gradually accumulate until no open water
remains.
Summary
1. Wetlands are important components of the
landscape all over the globe. The wetlands
stand testimony for the growth and propagation of many civilisations in the world. But
modern history of wetlands is shrouded with
some amount of misunderstanding and negligence about them. This has been leading to
their gradual (often fast) damage and dereliction. This has been posing threat to civilisation and ecology with regard to potential
habitat for meeting requirements of nutrition,
avocation, habitation and so on.
2. Wetlands have been regarded as kidneys of the
landscape. It is because they function as the
downstream receivers of water and wastes
from both natural and human sources.
3. Recently, wetlands have become the cause
célèbre for conservation-minded people and
organisations of the world.
4. Wetlands are sometimes diffi cult to defi ne
precisely, not only because of their great geographical extent, but also because of the wide
variety of hydrologic conditions in which they
are found.
5. Wetland science or wetland ecology or telmatology is that branch of science which deals
with a specialised study of the wetlands.
Persons who do such specialised study of wetlands are called wetland scientists or wetland
ecologists or mire ecologists .
6. Our knowledge of different wetland types is,
for the most part, isolated in distinctive literatures and scientifi c subjects. However, there is
an urgent need for a universal defi nition of
wetlands, though it is, sometimes, diffi cult to
get one. The term ‘wetland’ did not come into
common use until the mid-twentieth century.
Precise defi nition of wetland is needed by distinct interest groups, namely,
(a) Wetland scientists and (b) wetland managers and regulators
Nevertheless, some of the scientifi c defi nitions of wetlands are as follows:
1. The term ‘wetland’ refers to lowland covered
with shallow and sometimes temporary water.
2. Wetlands are waterfowl habitats according to
Circular 39.
11 Wetlands in the Landscape: Their History, Defi nitions, Origin and Evolution