Workshop on Palaeochannels - evolution and
ground water prospects held
Palaeochannels evoke interest in view of its geological/
tectonic history, sediment domain and ground water prospects. Palaeochannel deposits are unconsolidated fluvial
sediments, often coarse grained than adjoining flood plain deposits, and are valuable
from ground water point of view. This was stated by Union Minister for State
for Water Resources, River Development and Ganga Rejuvenation Prof. Sanwar Lal
Jat while inaugurating a workshop on “Palaeochannels - Evolution and
Ground Water Prospects” in New Delhi today. He said because
of better flushing mechanism in the ground water system of palaeochannels due
to coarser nature of sediments and fast recharge, the quality of ground water
is often better than the surrounding environment. The Minister said Palaeochannels
of Late Quaternary (1- 0.5million year) period are of particular interest from
ground water point of view. Optimum utilization of water resources warrants
detailed understanding of ground water prospects of the palaeochannels, the
Minister added.

With an objective to promote wide-ranging discussions on
palaeochannels of India and collate available information and research outputs,
Central Ground Water Board (CGWB) under Ministry of Water
Resources, River Development and Ganga Rejuvenation organized the day
long workshop. The workshop synthesized views, ideas, information through
deliberations by pan-India experts, stakeholders etc. The focal points of the
deliberations were geologic/ climatic/ tectonic reasons for disappearance of
rivers, location, alignment and geometry of palaeochannels, sedimentological
characteristics, ground water prospects and recharge potentials, developing
priorities for future investigation and research.
CGWB
has already organized three such workshops at Ahmadabad (July 2015), Allahabad
(October 2015) and Jodhpur (March 2016). Discussion and deliberations of these
workshops helped understanding the suitable methodologies to delineate the
palaeochannels including synergetic and integrated use of multi-sensory
satellite data, aerial photo, advance geophysical investigations,
hydro-geochemical modeling, hydrogeological investigation, characterizing the
sediments through drill cut samples etc. Substantial
work has been done on those aspects by CGWB, State Ground Water Departments,
Research Organizations, Academic Institutes and individual researchers.

Rivers,
through ages, have been lifeline of civilizations in the World and Indian
subcontinent as well. Besides the existing flowing rivers with active flood
plains, there are remnants of old rivers which are identifiable. These remnants
are called palaeochannels, and are characterized by relatively coarse clastics,
in comparison to their floodplains over the banks.
Palaeochannels have been
reported from different parts of India, covering the Indo-Gangetic plains as
well as the central and peninsular India. Several ancient rivers now
turned into Palaeochannels, which once supported civilization, agriculture and
economic growth along its flood plains. Of all the
reported palaeochannels, most widely researched, investigated and discussed are
those located in the western and north-western parts of India, covering the
states of Haryana, Rajasthan and Gujarat which is often linked to erstwhile
mighty river Sarasvati.

It has always been intriguing to
the researchers as to how the rivers migrate, disappear or get captured,
leaving palaeochannels thereby. The palaeochannels reveal plethora of
information about the history of the rivers, palaeoclimate, sedimentation process
and the civilization along its banks, interwoven with its course and flood
plains.
Samir/jk 