Impacts of climate change on hydrological regimes in the Jinsha River
Basin, China
Abstract
The flow regime is of vital importance for the sustainable development
of both human society and aquatic biota. Alterations in natural
streamflow will modify the stability and biophysical distribution of
river conditions, causing a series of adverse ecological and economic
consequences. Climate change has been proven to pose potential threats
to ecosystems; however, few studies have been conducted to quantify the
variations between the flow regime of a future period and pristine
natural flow specifically. This study investigates the future impacts
induced by the changing climate in the Jinsha River Basin, which is
known as the “Asian Water Tower” due to its rich hydroelectric energy
resources. The SWAT model is used and calibrated to predict future
streamflow. Seven GCMs from NASA NEX-GDDP with one ensemble average
under two RCPs (RCP4.5 and RCP8.5) are used for both the NFP (2040s) and
the FFP (2080s). The Indicators of Hydrologic Alteration (IHA) software
and the river regime index (RRI) are used to assess the potential flow
alterations of the Jinsha River. The results show that Pr, Tmax and Tmin
all denote increasing trends, with the temperature trends being more
obvious. For interannual alterations in flow regimes, most IHA values
show moderate and high changes in all predicted conditions. In regard to
the intra-annual changes, the results of the RRI show that river flow
tends to be more concentrated in wet seasons than in cold seasons and
denote evident seasonality and transience with advanced overall peaks of
the river system. These findings together indicate that the flow
patterns may have noticeable changes corresponding to the natural river
regime.