Hydrological Response of the Kunhar River Basin in Pakistan to Climate Change and Anthropogenic Impacts on Runoff Characteristics

Abstract

Pakistan is amongst the most water-stressed countries in the world, with changes in the frequency of extreme events, notably droughts, under climate change expected to further increase water scarcity. This study examines the impacts of climate change and anthropogenic activities on the runoff of the Kunhar River Basin (KRB) in Pakistan. The Mann Kendall (MK) test detected statistically significant increasing trends in both precipitation and evapotranspiration during the period 1971–2010 over the basin, but with the lack of a statistically significant trend in runoff over the same time-period. Then, a change-point analysis identified changes in the temporal behavior of the annual runoff time series in 1996. Hence, the time series was divided into two time periods, i.e., prior to and after that change: 1971–1996 and 1997–2010, respectively. For the time-period prior to the change point, the analysis revealed a statistically significant increasing trend in precipitation, which is also reflected in the runoff time series, and a decreasing trend in evapotranspiration, albeit lacking statistical significance, was observed. After 1996, however, increasing trends in precipitation and runoff were detected, but the former lacked statistical significance, while no trend in evapotranspiration was noted. Through a hydrological modelling approach reconstructing the natural runoff of the KRB, a 16.1 m3/s (or 15.3%) reduction in the mean flow in the KRB was simulated for the period 1997–2010 in comparison to the period 1971–1996. The trend analyses and modeling study suggest the importance of anthropogenic activities on the variability of runoff over KRB since 1996. The changes in streamflow caused by irrigation, urbanization, and recreational activities, in addition to climate change, have influenced the regional water resources, and there is consequently an urgent need to adapt existing practices for the water requirements of the domestic, agricultural and energy sector to continue being met in the future.

Assessing spatiotemporal trends of total and extreme precipitation in a subtropical highland region: A climate perspective

“…The decreasing trend in total annual, seasonal (winter and monsoon) precipitation, intensity-based indices, and frequency-based indices indicate that the overall frequency and severity of extreme precipitation events are reducing over time and space [2, 17, PLOS ONE 25,30,39]. This pattern can be related to the ongoing consequences of climate change, including increased temperatures, changing air circulation patterns, and decreased soil moisture levels [31,40,41]. These factors are leading to changes in precipitation patterns and intensities, with wet regions becoming drier and dry regions becoming even more arid [42].…”

Climate-Streamflow Relationship and Consequences of Its Instability in Large Rivers of Pakistan: An Elasticity Perspective

“…In Equation ( 2), variables P and Q are quite general and can be used as instantaneous, monthly, or annual values [77][78][79]. In this study, the mean annual values of streamflow Q and precipitation P for the estimation of ε p were utilized.…”

“…Similarly, it was also found that the regression analysis that includes temperature improves the coefficient of determination (R 2 ) [40]. Since all the subsequent research based on multivariate models suggests that multivariate models are more reliable than bivariate elasticity models [39,42,48,[73][74][75][76][77][78][79][80][81][82], it is believed that the multivariate elasticity results of our study are more authentic than the bivariate elasticity results, although there is very small difference between the results as discussed in Section 3.1 above.…”

“…Thus, the results of temperature are not reliable and are misleading. Furthermore, the existing literature also suggests that there is no significant impact of residual temperature on the streamflow compared to the direct and much more significant impact of precipitation on the streamflow, all because of the opposite correlation between precipitation and temperature [76][77][78][79][80][81][82].…”

Meteorological and Hydrological Drought Risk Assessment Using Multi-Dimensional Copulas in the Wadi Ouahrane Basin in Algeria

“…At the same time, at higher elevations or latitudes, climate change is expected to weaken the modulating effect of snow and glacier fields, with possibly strong impacts on hydropower generation, floods and droughts, irrigation water supplies, and associated food production [9]. Moreover, the variability of a hydrological regime is strongly affected by anthropogenic actions such as irrigation, urbanization, and recreational activities [10]. In particular, land cover change is a dominant factor affecting ecosystems [11,12] and the hydrological regime [13].…”