Quantification of Water Sustainability in Upper Indus River Basin Through the Concept of Resilience, Reliability and Vulnerability (RRV)

<p>The sustainability index identifies a strategy that defend or improve the desired water management features of the basin in the future. The Upper Indus river basin is a high mountain region and consider third freshwater tower. The flow of the river consists of melting glaciers, snow, rainfall. Beyond the polar regions, the Upper Indus Basin has the largest area of glaciers in the world (22,000 km<sup>2</sup>).  About 220 million people depend on Indus Basin water for agriculture and drinking purpose. Under the changing climate, sustainability is becoming a challenge for the freshwater resources. The integration of climate variables with RRV indicators is a new approach to meet this challenge. In this study the sustainability of the upper Indus is quantified. The probabilistic concept of resilience, reliability and vulnerability is applied to rainfall variability and drought patterns. The monthly Standardized Precipitation-Evapotranspiration Index (SPEI) grided data (0.5<sup>o</sup> 0.5<sup>o</sup>) generated by climate research unit (CRU)version 4 has been used for study during the period 1901–2018. Based on the SPEI pattern, the SPEI of -0.5 was selected as the threshold (demand) to evaluate the sustainability. The results indicate the frequency of drought events in the western part of the basin is much higher than the eastern part. However, the frequency of drought events in the basin is high but the capability of the basin to resilient the droughts varies from 0.57 to 0.83. The value of reliability indicator varies from 0.8 to 0.86 and vulnerability of drought in the basin is in the range of 0.2 to 0.45. The average water sustainability index of the basin is 0.4 which lies in the category of a satisfactory<strong> </strong>state.The results of the conceptual framework of RRV can provide a more comprehensive basis for designing watershed health variables and drought management plans.</p><p> </p><p><strong>Keywords: Upper Indus Basin, Water sustainability, RRV concept, SPEI, Drought.</strong></p>