13.6 Conclusion
An understanding of temporal distribution and
changing patterns in rainfall is a basic and
important requirement for the planning and
management of water resources. The present
study examines the variability and trends in
annual and seasonal rainfall for the eight districts
of BHB, West Bengal. The investigation showed
a long-term insignificant decline trend of annual
as well as pre-monsoon and winter rainfall,
whereas an increasing trend in southwest and
post-monsoon season. During monsoon season
the monthly rainfall in June and August were
found to be in decreasing trend, but there was
increasing trend in the month of July and
September. There was a major shift in rainfall
pattern temporarily during recent years as seasonal rainfall during the pre-monsoon was
declining while increasing in post-monsoon
season. Analysis of 100 years of (1901–2000)
monsoon rainfall also revealed that the basin
received 23 normal monsoon years, while
4 years received excess and 73 years received
deficit monsoon rainfall. In the present study, the
long term data set though has shown statistically
insignificant trend at 95% level, it may not
explain problems of real fact. However, the
shorter period of recent database showing higher
significance may have better practical utility.
This has an implication in water resource
development projects that depend on water from
rivers. The trends and variability of rainfall
clearly indicate the climatic impact that can have
adverse impact on economic development of the
basin. To minimize the climatic impacts, proper
adoption and mitigation measures are required to
be taken, but we cannot have control on natural
factors causing climate change, while the
anthropogenic activities can be controlled. As
anthropogenic forcing should have caused a
small increase in global mean precipitation
(Zhang et al. 2007), it is recommended that
people should overcome the problem by reducing
interventions. The other way of coping with this
problem is to diversify the economic base of the
populace with emphasis on reducing over
dependence on rain-fed agriculture. Finally, the
assessment of rainfall trend in temporal and
spatial scales is necessary for BHB including
West Bengal state to have a detailed information
at district level for better understanding and
control over disasters and management of water
resources. The results from the study would be
useful for proper management of water resources
as well as economic development of the basin
with special reference to agriculture. Accordingly, the formulation of government policies for
development in this area should essentially be
based on recent rainfall trends.
Acknowledgements The authors wish to express their
gratitude toward Department of Geography, The University of Burdwan for providing all the facilities needed for
preparing this manuscript. Indian Meteorological
Department (IMD), Government of India and Irrigation
and Waterways Department, Government of West Bengal
are thankfully acknowledged for providing the district
rainfall data sets and flood event occurrences for this
research, respectively. Indian Council of Social Science
Research (ICSSR) is duly acknowledged for study grant
(Ref. No. ICSSR-ERC/2014-15/15) to visit and consult
libraries for collecting research materials. Author (S.B.)
acknowledges the financial support in the form of grants
provided by International Association for Mathematical
Geosciences (IAMG) for carrying out part of this
research. The present research work is a contribution to
the thrust areas of UGC-SAP-DRS Programme.
References
Bagchi K (1972a) Editor's note. In Bagchi K (ed) The
Bhagirathi-Hooghly Basin (Proc Interdisciplinary
Symp.), Cal. Univ., Cal., pp v-vii
Bagchi K (1972b) Introduction by the director of the
symposium. In Bagchi K (ed) The BhagirathiHooghly basin (Proc Interdisciplinary Symp), Cal.
Univ., Cal., pp ix–xi
Basu SR (1967) On some aspects of fluvial dynamics of
River Bhagirathi with special reference to its physical
and hydraulic characteristics. Indian J Power River
Valley Develop XVII(6):32–42
Basu SR (2005) Recent findings on the river dynamics of
Bengal: Post Farakka condition of the off-take and
bank erosion of the River Bhagirathi-Hugli. Geograph
Rev India 67(4):315–346
Bates BC, Kundzewicz ZW, Wu S and Palutik JP (2008)
Climate change and water. Technical paper of the
intergovernmental panel on climate change, pp 33–48
180
N. C. Jana et al.
An understanding of temporal distribution and
changing patterns in rainfall is a basic and
important requirement for the planning and
management of water resources. The present
study examines the variability and trends in
annual and seasonal rainfall for the eight districts
of BHB, West Bengal. The investigation showed
a long-term insignificant decline trend of annual
as well as pre-monsoon and winter rainfall,
whereas an increasing trend in southwest and
post-monsoon season. During monsoon season
the monthly rainfall in June and August were
found to be in decreasing trend, but there was
increasing trend in the month of July and
September. There was a major shift in rainfall
pattern temporarily during recent years as seasonal rainfall during the pre-monsoon was
declining while increasing in post-monsoon
season. Analysis of 100 years of (1901–2000)
monsoon rainfall also revealed that the basin
received 23 normal monsoon years, while
4 years received excess and 73 years received
deficit monsoon rainfall. In the present study, the
long term data set though has shown statistically
insignificant trend at 95% level, it may not
explain problems of real fact. However, the
shorter period of recent database showing higher
significance may have better practical utility.
This has an implication in water resource
development projects that depend on water from
rivers. The trends and variability of rainfall
clearly indicate the climatic impact that can have
adverse impact on economic development of the
basin. To minimize the climatic impacts, proper
adoption and mitigation measures are required to
be taken, but we cannot have control on natural
factors causing climate change, while the
anthropogenic activities can be controlled. As
anthropogenic forcing should have caused a
small increase in global mean precipitation
(Zhang et al. 2007), it is recommended that
people should overcome the problem by reducing
interventions. The other way of coping with this
problem is to diversify the economic base of the
populace with emphasis on reducing over
dependence on rain-fed agriculture. Finally, the
assessment of rainfall trend in temporal and
spatial scales is necessary for BHB including
West Bengal state to have a detailed information
at district level for better understanding and
control over disasters and management of water
resources. The results from the study would be
useful for proper management of water resources
as well as economic development of the basin
with special reference to agriculture. Accordingly, the formulation of government policies for
development in this area should essentially be
based on recent rainfall trends.
Acknowledgements The authors wish to express their
gratitude toward Department of Geography, The University of Burdwan for providing all the facilities needed for
preparing this manuscript. Indian Meteorological
Department (IMD), Government of India and Irrigation
and Waterways Department, Government of West Bengal
are thankfully acknowledged for providing the district
rainfall data sets and flood event occurrences for this
research, respectively. Indian Council of Social Science
Research (ICSSR) is duly acknowledged for study grant
(Ref. No. ICSSR-ERC/2014-15/15) to visit and consult
libraries for collecting research materials. Author (S.B.)
acknowledges the financial support in the form of grants
provided by International Association for Mathematical
Geosciences (IAMG) for carrying out part of this
research. The present research work is a contribution to
the thrust areas of UGC-SAP-DRS Programme.
References
Bagchi K (1972a) Editor's note. In Bagchi K (ed) The
Bhagirathi-Hooghly Basin (Proc Interdisciplinary
Symp.), Cal. Univ., Cal., pp v-vii
Bagchi K (1972b) Introduction by the director of the
symposium. In Bagchi K (ed) The BhagirathiHooghly basin (Proc Interdisciplinary Symp), Cal.
Univ., Cal., pp ix–xi
Basu SR (1967) On some aspects of fluvial dynamics of
River Bhagirathi with special reference to its physical
and hydraulic characteristics. Indian J Power River
Valley Develop XVII(6):32–42
Basu SR (2005) Recent findings on the river dynamics of
Bengal: Post Farakka condition of the off-take and
bank erosion of the River Bhagirathi-Hugli. Geograph
Rev India 67(4):315–346
Bates BC, Kundzewicz ZW, Wu S and Palutik JP (2008)
Climate change and water. Technical paper of the
intergovernmental panel on climate change, pp 33–48
180
N. C. Jana et al.