Development of Threshold Levels and a Climate-Sensitivity Model of the Hydrological Regime of the High-Altitude Catchment of the Western Himalayas, Pakistan

Abstract

Water shortages in Pakistan are among the most severe in the world, and its water resources are decreasing significantly due to the prevailing hydro-meteorological conditions. We assessed variations in meteorological and hydrological variables using innovative trend analysis (ITA) and traditional trend analysis methods at a practical significance level, which is also of practical interest. We developed threshold levels of hydrological variables and developed a non-parametric climate-sensitivity model of the high-altitude catchment of the western Himalayas. The runoff of Zone I decreased, while the temperature increased and the precipitation increased significantly. In Zone II, the runoff and temperature increased but the precipitation decreased. A two-dimensional visualization of the Pardé coefficient showed extreme drought events, and indicated greater sensitivity of the hydrological regime to temperature than to precipitation. The threshold levels of runoff for Zones I and II were 320 and 363 mm using the Q 80 fixed method, while the mean runoff amounts were estimated to be 79.95 and 55.61 mm, respectively. The transient threshold levels varied by month, and the duration of droughts in Zones I and II ranged from 26.39 to 78.98 days. The sensitivity of the hydrological regime was estimated based on a modified climate-elasticity model (ε p = 0.11-0.23, ε t = −0.04-2.39) for Zones I and II, respectively. These results highlight the sensitivity of the hydrological regime to temperature, which influences the melting process. However, it is important to establish thresholds for hydrological variables and understand the climate sensitivity of the hydrological regime of the entire basin, so that policy makers and water managers can make sustainable water-resource-management decisions for this region.

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

“…Furthermore, [75] found an increase in the frequency of wet precipitation days from the northeast to the middle parts of the northern highlands of Pakistan. The trends in temperature and precipitation of our previous study i.e., [45] were found consistent with our current study but runoff in the upper part of the KRB was found to increase in comparison to the lower part (downstream) of the basin. Moreover, [3] also identified the lack of a trend in the runoff of the upper and middle stream of the Syr Darya River basin, and their results were found consistent with our current study.…”

“…Moreover, Khattak [78] observed increasing trends in temperature and runoff but noted an inconsistent pattern for precipitation trend in UIB, Pakistan. Their precipitation and temperature innovative trends were found consistent, whereas runoff innovative trends were found conflicting with the findings of [45].…”

“…A study conducted by Saifullah et.al. [45] determined the threshold levels and a climate-sensitivity model for the hydrological regime of the KRB. The current study is directly associated with the water-related ecosystem that is designed in accordance with the Sustainable Development Goals of the United Nations (SDGs 6.3), to integrate climate change measures and policies (SDGs 13.2), and anthropogenic impacts (SDGs 15.1.1).…”

Evaluating Hydrological Responses to Climate Change

“…One of the most obvious manifestations of climate change is its influence on water balance and hydrological processes across the globe, and there is notably a heightened awareness of hydrological responses to climate variations [1]. Impacts vary across the globe, with recent climate variations and developments impacting ecological conditions in the Small Aral Sea in Russia [2]; water shortages in Pakistan, which are among the most severe in the world [3] and further impact ecosystem services [4]; and increased droughts in the semi-arid northeastern region of Brazil, which is one of the poorest rural communities in the country [5]. The Tibetan Plateau in Pakistan, referred to as the "Water Tower of Asia", owing to its unique geographical characteristics, plays an important role in the East Asian and global atmospheric circulation patterns, and is experiencing warming with profound impacts on snowmelt and sustainable water resources for major rivers in Asia [6].…”

“…Addressing different parts of the water balance, from precipitation [6] and evapotranspiration [9] to runoff [1][2][3]7,8] and impacts to water resources [2][3][4][5]7,8], these papers investigated the performance of hydrological models and GCMs, projected ecological and hydrological changes to basins [1,2,[4][5][6][7][8], and used a suite of analytical and numerical tools to improve both historical calibration/validation capabilities [2,8] and future climate modeling performance [4,5,9].…”