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Droughts are one of the multidimensional extreme events that negatively influence agriculture, water availability and food security in the World. The Upper Indus Basin (UIB) is the major river system in the world that contributes 80% of the surface water availability in Pakistan. The objective of the current study is to analyze the spatial patterns of drought severity and magnitude using the standardized precipitation index and streamflow drought index. These drought indices were used to estimate the characteristics and a variation of the droughts annual, pre-monsoon and post-monsoon seasons for the period of 1991–2017. Results revealed that the northeastern side of the Upper Indus Basin was greatly influenced by the droughts as compared to the southwestern side. The duration from 1997 to 1998 was strongly correlated with El Nino and La Nina (ENSO) in a strong way. This type of ENSO indicates the severe drought for 5 years from 1998 to 2002 in the UIB. The episode of the warm water oceans mechanism was also strengthened in 1996, 1997, 1998, 2000, 2001 and 2002 drought years. La Nina effect has been observed in the wet and cold phase during the year of 1999. The study indicated the severe SDI drought in the years of 1991 and 2001. The study also indicated that the streamflow drought index in the post-monsoon season was marked by extreme level drought magnitude at G. Habibullah (2001), Muzaffarabad (2001), Yogo (1993) and Dhok Pathan (1998). The results of the current investigation would help policymakers to introduce new types of drought risk reduction measures for drought preparedness at the regional and the national level in Pakistan. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mann-Kendall trend test were used over the spatio-temporal scale. • Impact of land use was determined by MODIS (MCD12Q1) and digital elevation model. • Land use changes are major factors to change the hydrological process of CRB. Adverse impacts of climate change on the ecosystem have been a significant concern in the last decades. However, the studies related to the impacts of climate change on water resources, especially in northern Pakistan are of great importance as this region is the main supplier of freshwater to the downstream areas. So, the present study was carried out in Chitral River Basin (CRB) to investigate the long term climatic and topographic changes. Spatiotemporal datasets from MODIS Land Cover Type product (MCD12Q1) from 2001 to 2018, ground-based observational climatic and hydrological data were used. Moreover, the Mann-Kendall trend test, linear regression analysis, correlation, and Sen's slope values for the mean annual and seasonal flows were assessed. The acquired results show that land use changes are the key non-natural factors in transforming the ecological and hydrological processes of CRB. The mixed and evergreen forest, shrubland, savannas, and barren land respectively decreased from 0.07 to 0.03%, 0.07 to 0.05%, 3.64 to 3.25%, and 70.10 to 67.17%, from 2001 to 2018. In addition, a considerable increment in snow cover from 8.79% to 10.71%, and slight increment in grasslands, wetlands, and croplands were also found between the period of observation. In addition, total annual precipitation and mean annual stream flow showed slight upward trends. Annual increment in total rainfall and snow covered area could be the possible reasons for the observed increased river flow. [ABSTRACT FROM AUTHOR]

Drought is a natural event that can have significant impact on the economy. Pakistan is a semi-arid country where hydrological drought generally causes adverse impacts on agricultural production and hydropower generation. In this research, the characteristics of hydrological droughts in Indus River basin using stream flow data of major rivers of Pakistan were investigated. Stream flow drought indices (SDI) were used to determine the severity of droughts for the Indus, Jhelum, Chenab and Kabul River at Tarbela, Mangla, Marala and Warsak hydrological stations for the period 1962-2011. A drought spell starting from 1999 and ending in 2002 was observed for all stations and is considered to be the worst drought in the history of Pakistan. Analysis of historical streamflow data indicated an increased occurrence of droughts in the last 12 years, which may be attributed to climate change. Extreme drought events were observed at Tarbela during October-September and at Mangla during October-June with SDI value of -2.36 and -2.74, respectively. Moderate to severe wet conditions were also detected in the analysis period. Several strategies for the mitigation of adverse impacts of droughts in the study region are recommended. [ABSTRACT FROM AUTHOR]

The main objective of this study is to evaluate discernible long term trends in streamflows of four major rivers of Pakistan, namely Kabul, Indus, Jhelum, and Chenab. For each river, the first hydrological station where flow rate is measured after its entry to Pakistan, has been selected. The stations, thus selected on Kabul, Indus, Jhelum and Chenab are Warsak, Tarbela, Mangla and Marala, respectively. The average monthly streamflow data for each of the four stations was collected from Irrigation department, Lahore for the period 1962-2011. The annual as well as seasonal analysis of average monthly streamflows was conducted using the Mann Kendall non-parametric test. For each case, the trend slopes were estimated using the Sen's slope method. A trend free pre-whitening (TFPW) approach was used to account for the auto correlation in the time series. Results indicate increasing trends for winter streamflows and decreasing trends for summer streamflows. For the spring season, Warsak exhibited decreasing trend, whereas the other stations showed increasing trends. Annual flow had a decreasing trend at all stations. The trends identified in this study may be partially attributed to the effects of climate change in Pakistan. [ABSTRACT FROM AUTHOR]