Contributions of Climate Change and Human Activities on Runoff
Variations in the Central Part of Tajikistan in Central Asia
Abstract
Comprehensive studies of the contributions of climate variation and
anthropogenic activities to runoff alterations are essential for
sustainable management of water resources in Central Asian countries. In
the Kofarnihon River Basin (KRB) in Central Asia, both changing climate
conditions and anthropogenic activities are known to have caused
variations to the hydrological cycle. Therefore, quantifying the net
influence of human contribution to the runoff changes is a challenge. In
this study, by applying the original and modified Mann–Kendall trend
test, Pettitt test, double cumulative curve and elasticity methods the
historical trends and breakpoint changes of the hydro-climatic variables
including temperature, precipitation, potential evapotranspiration, and
runoff over the 1950–2016 along were determined, in addition the
contributions of climate variation and anthropogenic activities to
runoff changes in the KRB were evaluated. The trend analysis exhibited a
significant increasing trend in annual temperature and potential
evapotranspiration and the annual precipitation trend showed
insignificant decreasing trend during the 1950–2016 time period. The
breakpoint change was detected in runoff occurs in 1991. Further, the
time series (1950–2016) are separated into the prior impacted period
(1950–1991) and post impacted period (1992–2016) with trend test. The
results showed that anthropogenic activities played a dominant role in
changes in the runoff with a contribution of 79.94% in the upstream and
97.78% in the downstream of the KRB. Climate change contributed to
20.06% in the upstream and 7.53% in the downstream of the catchment
during the post impacted period. In the land-use type changes, the
dominant role played construction land which showed that the area from
248.63 km2 in 1990 increased to 685.45 km2 (175.69%) in 2015. The
findings suggest that it is essential to adopt effective steps for
sustainable development of ecological, hydrological and social order in
the KRB in Central Asia.