Empirical Approach-Based Potential Impact Analysis of Climate
Change and Land-Use Conversions on Streamflow Variations: A Case Study
of the Brahmani Catchment
Sushree Swagatika Swain 1, Ashok
Mishra2, Chandranath Chatterjee2
1School of Water Resources, Indian Institute of
Technology Kharagpur
2Agricultural and Food Engineering Department, Indian
Institute of Technology Kharagpur
Contact: sushreeswain1991@gmail.com
Streamflow, the fundamental element of catchment-scale hydrology, is
expressed as a complex response of many hydrological processes that
includes atmospheric forcing (precipitation and temperature) and human
activities (land-use change, reservoir/dam construction, and excessive
water exploitation). Thus, change in climate variables and land-use
alter a catchment’s streamflow pattern, which is a critical concern to
the researchers. In the present study, the potential contributions of
Climate Change (CC) and Land-use Conversions (LC) on streamflow
variations are quantified for the Brahmani catchment (36800
km2) of eastern India. The estimation procedure is
followed by two empirical approaches, i.e. (i) the modified Double Mass
Curve (m-DMC) method and (ii) the modified Slope Change Ratio of
Accumulative Quantity (m-SCARQ) method. The abrupt changes in streamflow
data series are checked by the sequential Mann-Kendall method. Multiple
change points, including 1981, 1985, 1993, 1994, 2011, and 2013 are
observed in streamflow data series in the study area. However, 1994 is
selected as the break-point, which has the highest significance value,
i.e. 1.92. Therefore, the entire analysis period (1979-2018) is divided
into two sub-periods, i.e. the baseline period (1979-1994) and the
assessment period (1995-2018). Further, the statistical characteristics
(trend, slope, and significance) of hydro-climatic variables
(precipitation, temperature, and streamflow) are analysed by applying
the Mann-Kendall method followed by the Sen’s slope estimator for all
the periods. Using the m-DMC method, the potential contributions of CC
(βCC) and LC (βLC) in the assessment
period are quantified as 93.09% and 6.91%, respectively. However, from
m-SCARQ, the contributions of precipitation (βP),
temperature (βT), CC (βCC), and LC
(βLC) on streamflow variations are 0.26%, 19.74%,
20%, and 80%, respectively. The outcomes of the m-DMC other than the
m-SCARQ method showed that streamflow variation is more sensitive to
climate change of the study area. Further, the m-SCARQ method is
relatively strategic compared to the m-DMC method since it can signify
the contributions of precipitation (βP) and temperature
(βT) on the streamflow variations. Still, both the
empirical approaches are attributed to different sources of errors and
uncertainty with individual advantages. Accordingly, this study can
provide new insights concerning the relative resistance of the Brahmani
catchment’s response to CC and LC that is vital for the prudent planning
and management of future water resources.
Keywords: Climate change; Land-use conversions; m-DMC method;
m-SCARQ method; Brahmani