Spatio-Temporal Pattern in the Changes in Availability and Sustainability of Water Resources in Afghanistan

Water is gradually becoming scarce in Afghanistan like in many other regions of the globe. The objective of this study was to evaluate the spatial changes in the availability and sustainability of water resources in Afghanistan. The Terrestrial Water Storage (TWS) data of the Gravity Recovery and Climate Experiment (GRACE) satellite obtained from three different institutes, having 1° × 1° spatial resolution for the period 2002–2016 was used for this purpose. Sen’s slope method was used to assess the rate of change, and the Modified Mann–Kendall test was used for the evaluation of the significance of trends in TWS. After, the concept of reliability–resiliency–vulnerability (RRV) was used for assessing the spatial distribution of sustainability in water resources. The results revealed a significant decrease in water availability in the country over the last 15 years. The decrease was found to be highest in the central region where most of the population of the country resides. The reliability in water resources was found high in the northeast Himalayan region and low in the southwest desert; resilience was found low in the central region, while the vulnerability was found high in the south and the southeast. Overall, the water resources of the country were found most sustainable in the northeast and southwest and least in the south and the central parts. The maps of water resource sustainability and the changes in water availability produced in the present study can be used for long-term planning of water resources for adaptation to global changes. Besides, those can be used for the management of water resources in a sustainable and judicious manner

Empirical model for the assessment of climate change impacts on spatial pattern of water availability in Nigeria

Rising temperatures and changing rainfall patterns due to global warming would affect sustainability in water resources in many regions. This change would impact several sectors, particularly the agricultural and water resources. The major objective of the present study is to model the impacts of climate change on spatial variability in water sustainability of Nigeria. Gauge based gridded rainfall data of global precipitation climatology centre (GPCC) and temperature data of climate research unit (CRU) for the period 1901–2010 and total water storage (TWS) anomaly data of Gravity Recovery and Climate Experiment (GRACE) for the period 2002–2016 were used for this purpose. The concept of reliability-resiliency-vulnerability was used for the assessment of sustainability in water resources. Machine learning models were used for the development of empirical models for the simulation of TWS from GPCC rainfall and CRU temperature. Finally, the multi-model ensemble mean projections of rainfall and temperature of four GCMs namely MRI-CGCM3, HadGEM2-ES, CSIRO-Mk3-6-0 and CESM1-CAM5 were used in the model for the assessment of climate change impact on water sustainability. The results revealed the declination of TWS in Nigeria up to -12 m during the rainy periods in some parts. Spatial assessment of the changes in TWS for the future shows the northeast, southeast and south-south parts would mostly experience decreases in TWS. Water sustainability will be low in these areas and some other parts of the country for the future