Abstract:
Water resources management in the arid and semi-arid areas is a quite a
challenging task owing to the large number of hydrologic, environmental and management
factors. The climate change has opened up a new spectrum of challenges viz., higher
occurrences of extreme events like droughts, floods and heat waves alongwith increased
variability of rainfall and uncertain water availability scenario in the future. Investigations
have been carried out to detect the climate change signals in the historical climate datasets for
the Chambal basin in Madhya Pradesh. The average annual rainfall has decreased from
1038.5 mm during 1931-60 to 951.40 mm during 1961-90 and 925.10 mm during 2001-2015.
The average annual rainfall varies spatially, with decreasing rainfall from east to west
(districts bordering Rajasthan) viz., 800-900 mm in the districts of Neemuch, Mandsaur,
Ratlam and parts of Ujjain and Dhar districts, 900 – 1000 mm in the districts of Agar, Indore,
major parts of Ujjain and parts of Dhar, Dewas, Shajapur and Rajgarh districts, 1000 – 1100
mm) at Guna, parts of Rajgarh, Shajapur, Dewas, Vidisha and Sehore districts and > 1100
mm in the eastern parts falling partly in the districts of Bhopal, Rajgarh, Shajapur and Sehore.
The comparison of the number of rainy days between the baseline period (1961-90) and
present period (1991-2015) indicates considerable decrease in the number of rainy days in 47
out of the 53 blocks in the study area. The extreme rainfall (P>200 mm/day) and very heavy
rainfall (P>100 mm/day) has also increased in most parts of the study area whereas a mixed
trend has been observed for heavy rainfall (P>50 mm/day). The 1-day maximum temperature
(1-day MaxT) has shown a significant rising trend at 5% significance level. The very hot days
(MaxT>40oC) and hot days (MaxT>35oC) have also increased significantly. The trends
detected in these indices suggest towards an increased scenario of water stress in the basin at
present as compared to the baseline period and investigations are necessary to understand the
impact of climate change on the future drought, desertification and water stress under the
challenge of climate change related impacts.
