Brief reporting on Sonai River/Khal in ... - India Water Portal

FOREWORD
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The present report is based on an ordered assimilation of available information and will serve as the
foundation for developing the strategy for urban environmental improvement and restoration of
Calcutta’s environment and also for safeguarding the city from future problems of ecological
imbalance. By completing this phenomenal work Dr. Dhrubajyoti Ghosh, Co-ordinator, Environmental
Improvement Programme and his team, have done a commendable job and deserve appreciation.
I hope this humble effort will be of some assistance to the people of Calcutta, the ultimate decision
makers for shaping their future environment.
15.3 WETLAND FORMATION AND DISTRIBUTION
Asok Bhattacharya, Minister-in-Charge, Department of
Urban Development, Government of West
Bengal – 5 June 1996
The Calcutta Metropolitan Area in the lower Gangetic plain is more or less flat. The principal drainage
line in the river Hugli. The river enters the Calcutta Metropolitan Area at Tribeni and leaves the region
at Uluberia. At Tribeni, the river Saraswati branches off to the west and the Jamuna to the east. The
entire Calcutta Metropolitan Area is traversed by innumerable offshoots of the river Hugli. The north
eastern part of the area comprises meander belts of the river forming large arcuate waterbodies like the
Mathura, the Kulia, the Maricha and the Baisar bils. The drainage lines in the area are highly
sluggish. Among the present day channels, the Hugli, the Jamuna and the Sunti are the more important
ones. Some of the palaeo-channels can be traced in the region by their highly aggraded beds. They
include the Adi Ganga, the Gouri Ganga, the Kana Damodar, the Sonai Nadi and the Bidyadhari
river. Land is naturally higher along both the banks of the existing palaeo-channels. Away from the
levees land slopes down till it reaches another river and rises. The interdistributary marshes are
numerous. The wetlands here have been formed by natural and anthropogenic causes and are
scattered all over the region. There are numerous small tanks of the size of less than 5000 sq. metres on
one hand and large wetlands of more than 16,000 ha. on the other. Generally depths of the wetlands
are never more than 3 metres and most are much shallower. Fluvial action has been the chief cause of
creation of the natural wetlands in this region. Man made water bodies found in the region are either
for water supply or are borrow pits found along the highways, railways and in brick-fields. Small tanks
less than 5000 sq. metres in area are mostly dug by man and they can be identified on a map by their
comparatively regular boundaries. (from Page No. 164 – 165)