scholarly journals Applying the Water-Energy Nexus for Water Supply—A Diagnostic Review on Energy Use for Water Provision in Africa

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2560
Author(s):  
Pauline Macharia ◽  
Norbert Kreuzinger ◽  
Nzula Kitaka

This work explores the application of the Water-Energy Nexus concept for water supply in the African context, where its operationalization is quite limited compared to developed regions. Furthermore, water supply and demand drivers and their influence on energy use are examined. This study found that there is limited literature available on the operationalization of the concept, and energy use is not considered a key performance indicator by water regulators and utilities. Regionally, most of the studies were carried out in the northern and southern Africa, where energy demand for water supply through desalination is high. An analysis of water supply and demand drivers show diminishing quantities of available freshwater, and increased anthropogenic pollutant loads in some areas are projected. Consequently, utilities will likely consider alternative energy-intensive water supply options. Increased population growth with the highest global urban growth rate is projected, with about 60% of the total population in Africa as urban dwellers by 2050. This implies huge growth in water demand that calls for investment in technology, infrastructure, and improved understanding of energy use and optimization, as the largest controllable input within utilities boundaries. However, it requires a data-driven understanding of the operational drivers for water supply and incorporation of energy assessment metrics to inform water-energy policies and to exploit the nexus opportunities.

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1522 ◽  
Author(s):  
Hadi Heidari ◽  
Mazdak Arabi ◽  
Mahshid Ghanbari ◽  
Travis Warziniack

Changes in climate, land use, and population can increase annual and interannual variability of socioeconomic droughts in water-scarce regions. This study develops a probabilistic approach to improve characterization of sub-annual socioeconomic drought intensity-duration-frequency (IDF) relationships under shifts in water supply and demand conditions. A mixture Gamma-Generalized Pareto (Gamma-GPD) model is proposed to enhance characterization of both the non-extreme and extreme socioeconomic droughts. Subsequently, the mixture model is used to determine sub-annual socioeconomic drought intensity-duration-frequency (IDF) relationships, return period, amplification factor, and drought risk. The application of the framework is demonstrated for the City of Fort Collins (Colorado, USA) water supply system. The water demand and supply time series for the 1985–2065 are estimated using the Integrated Urban water Model (IUWM) and the Soil and Water Assessment Tool (SWAT), respectively, with climate forcing from statistically downscaled CMIP5 projections. The results from the case study indicate that the mixture model leads to enhanced estimation of sub-annual socioeconomic drought frequencies, particularly for extreme events. The probabilistic approach presented in this study provides a procedure to update sub-annual socioeconomic drought IDF curves while taking into account changes in water supply and demand conditions.


Asian Survey ◽  
2019 ◽  
Vol 59 (6) ◽  
pp. 1116-1136
Author(s):  
Amit Ranjan

The widening gap between water supply and demand is the biggest threat and challenge before Pakistan. Of the available water, much is polluted. Both scarcity and pollution threaten the agriculture sector, on which the country’s economy depends.


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