Future Water Shortages Research Articles

How might climate change affect river flows across West Africa?

West Africa and its semi-arid Sahelian region are one of the world’s most vulnerable regions to climate change with a history of extreme climate variability. There is still considerable uncertainty as to how projected climate change will affect precipitation at local and regional scales and the consequent impact on river flows and water resources across West Africa. Here, we aim to address this uncertainty by configuring a regional-scale hydrological model to West Africa. The model (hydrological modelling framework for West Africa—HMF-WA) simulates spatially consistent river flows on a 0.1° × 0.1° grid (approximately 10 km × 10 km) continuously across the whole domain and includes estimates of anthropogenic water use, wetland inundation, and local hydrological features such as endorheic regions. Regional-scale hydrological simulations driven by observed weather data are assessed against observed flows before undertaking an analysis of the impact of projected future climate scenarios from the CMIP5 on river flows up to the end of the twenty-first century. The results indicate that projected future changes in river flows are highly spatially variable across West Africa, particularly across the Sahelian region where the predicted changes are more pronounced. The study shows that median peak flows are projected to decrease by 23% in the west (e.g. Senegal) and increase by 80% in the eastern region (e.g. Chad) by the 2050s. The projected reductions in river flows in western Sahel lead to future droughts and water shortages more likely, while in the eastern Sahel, projected increases lead to future frequent floods.

Seasonal differences in future climate and streamflow variation in a watershed of Northern China

Study regionThe Chaohe watershed is a meso-scale watershed in northern China, and the primary reservoir watershed for Beijing's drinking water supply. Study focusThis research aims to evaluate the effects of climate change on future seasonal streamflow regimes and understand the challenges to watershed management. The Regional Hydro-Ecological Simulation System (RHESSys) was applied to investigate the watershed's future hydrographic characteristics under the forcing of the downscaled precipitation and temperature projected by General Circulation Models (GCMs) under three emissions scenarios. New hydrological insights for the regionThe future climate exhibits a drier and warmer trend in the summer monsoon period contrasting with other seasons in the watershed. Precipitation will decrease by 47.5–57.2 mm during the summer monsoon period while increasing annually. Future summer streamflow will decrease accordingly, which is also driven by increased evapotranspiration due to rising temperature. An increased dispersion coefficient of streamflow also indicates more dramatic variations in summer. The annual streamflow magnitude with a 5-year return period increases significantly (p < 0.01), indicating a reduced risk for future water shortages. However, the magnitude of streamflow will decrease with the prolonged return periods (p < 0.01). This study emphasizes the critical significance of predicting the seasonal variability of streamflow and other hydrological property changes at the local scale to provide valuable information for developing adaptive resource management and hazard relief strategies.

Assessment of Drought Severity and Vulnerability in the Lam Phaniang River Basin, Thailand

The Lam Phaniang River Basin is one of the areas in Northeast Thailand that experiences persistent drought almost every year. Therefore, this study was focused on the assessment of drought severity and vulnerability in the Lam Phaniang River Basin. The evaluation of drought severity was based on the Drought Hazard Index (DHI), which was derived from the Standardized Precipitation-Evapotranspiration Index (SPEI) calculated for 3-month (short-term), 12-month (intermediate-term), and 24-month (long-term) periods. Drought vulnerability was assessed by the Drought Vulnerability Index (DVI), which relied on water shortage, water demand, and runoff calculated from the WEAP model, and the Gross Provincial Product (GPP) data. A drought risk map was generated by multiplying the DHI and DVI indices, and the drought risk level was then defined afterwards. The CNRM-CM5, EC-EARTH, and NorESM1-M global climate simulations, and the TerrSet software were used to evaluate the potential impacts of future climate under RCPs 4.5 and 8.5, and land use during 2021–2100, respectively. The main findings compared to baseline (2000–2017) revealed that the average results of future rainfall, and maximum and minimum temperatures were expected to increase by 1.41 mm, and 0.015 °C/year and 0.019 °C/year, respectively, under RCP 4.5 and by 2.72 mm, and 0.034 °C/year and 0.044 °C/year, respectively, under RCP 8.5. During 2061–2080 under RCP 8.5, the future annual water demand and water shortage were projected to decrease by a maximum of 31.81% and 51.61%, respectively. Obviously, in the Lam Phaniang River Basin, the upper and lower parts were mainly dominated by low and moderate drought risk levels at all time scales under RCPs 4.5 and 8.5. Focusing on the central part, from 2021–2040, a very high risk of intermediate- and long-term droughts under RCPs 4.5 and 8.5 dominated, and occurred under RCP 8.5 from 2041–2060. From 2061 to 2080, at all time scales, the highest risk was identified under RCP 4.5, while low and moderate levels were found under RCP 8.5. From 2081–2100, the central region was found to be at low and moderate risk at all time scales under RCPs 4.5 and 8.5. Eventually, the obtained findings will enable stakeholders to formulate better proactive drought monitoring, so that preparedness, adaptation, and resilience to droughts can be strengthened.

Enhancing Water Supply Resilience in a Tropical Island via a Socio-Hydrological Approach: A Case Study in Con Dao Island, Vietnam

Socio-hydrological approaches are gaining momentum due to the importance of understanding the dynamics and co-evolution of water and human systems. Various socio-hydrological approaches have been developed to improve the adaptive capacity of local people to deal with water-related issues. In this study, a social-hydrological approach was developed to enhance the water supply resilience in Con Dao Island, Vietnam. We used a water-balance model, involving the Water Evaluation and Planning (WEAP) tool, to conduct a scenario-based evaluation of water demands. In doing so, we assessed the impacts of socio-economic development, such as population growth and climate change, on increasing water demand. The modelling results showed that the existing reservoirs—the main sources to recharge the groundwater (accounting for 56.92% in 2018 and 65.59% in 2030)—play a critical role in enhancing water supply resilience in the island, particularly during the dry season. In addition, future water shortages can be solved by investment in water supply infrastructures in combination with the use of alternative water sources, such as rainwater and desalinated seawater. The findings further indicate that while the local actors have a high awareness of the role of natural resources, they seem to neglect climate change. To meet the future water demands, we argue that upgrading and constructing new reservoirs, mobilizing resources for freshwater alternatives and investing in water supply facilities are among the most suitable roadmaps for the island. In addition, strengthening adaptive capacity, raising awareness and building professional capacity for both local people and officials are strongly recommended. The research concludes with a roadmap that envisages the integration of social capacity to address the complex interaction and co-evolution of the human–water system to foster water-supply resilience in the study area.

Assessing the potential of partial root zone drying and mulching for improving the productivity of cotton under arid climate

Water scarcity constrains global cotton production. However, partial root-zone drying (PRD) and mulching can be used as good techniques to save water and enhance crop production, especially in arid regions. This study aimed to evaluate the effects of mulching for water conservation in an arid environment under PRD and to further assess the osmotic adjustment and enzymatic activities for sustainable cotton production. The study was carried out for 2 years in field conditions using mulches (NM = no mulch, BPM = black plastic mulch at 32 kg ha-1, WSM = wheat straw mulch at 3 tons ha-1, CSM = cotton sticks mulch at 10 tons ha-1) and two irrigation levels (FI = full irrigation and PRD (50% less water than FI). High seed cotton yield (SCY) achieved in FI+WSM (4457 and 4248 kg ha-1 in 2017 and 2018, respectively) and even in PRD+WSM followed by BPM>CSM>NM under FI and PRD for both years. The higher SCY and traits observed in FI+WSM and PRD+WSM compared with the others were attributed to the improved water use efficiency and gaseous exchange traits, increased hormone production (ABA), osmolyte accumulation, and enhanced antioxidants to scavenge the excess reactive oxygen. Furthermore, better cotton quality traits were also observed under WSM either with FI or PRD irrigation regimes. Mulches applications found effective to control the weeds in the order as BPM>WSM>CSM. In general, PRD can be used as an effective stratagem to save moisture along with WSM, which ultimately can improve cotton yield in the water-scarce regions under arid climatic regions. It may prove as a good adaptation strategy under current and future water shortage scenarios of climate change.

Effects of Urban Development Patterns on Municipal Water Shortage

While urban areas are being threatened by water shortage due to climate change and rapid population growth, effects of urban development patterns on future municipal water shortage are rarely investigated. We address this aspect of urbanization by assessing the impacts of sprawl vs. high-density patterns on future changes in the sub-annual water shortage intensity-duration-frequency (IDF) relationships. The City of Fort Collins, Colorado, water supply system is chosen as a representative region that is rapidly developing over the last decades. The future water supply is estimated using the Soil and Water Assessment Tool (SWAT) driven with a hot-dry climate model from the statistically downscaled Coupled Model Intercomparison Project, phase 5 (CMIP5) projections. Future water demand is projected using the Integrated Urban Water Model (IUWM) under both sprawl and high-density development patterns. The demonstration study reveals that urban areas under the sprawl development pattern are likely to experience water shortage events with higher intensity, duration, and frequency compared to the high-density pattern. Characterizing impacts of urban development patterns on future water shortage conditions is required for sustainable water management and smart urban growth and can help urban planners and water managers to develop an adaptive path to meet future water demand and decrease the vulnerability of municipal water supply systems to shortage.

Hydro-Economic Water Allocation Model for Water Supply Risk Analysis: A Case Study of Namhan River Basin, South Korea

Rational water resource management is used to ensure a stable supply of water by predicting the supply of and demand for future water resources. However, rational water allocation will become more difficult in the future owing to the effects of climate change, causing water shortages and disputes. In this study, an advanced hydro-economic water allocation and management model (WAMM) was introduced by improving the optimization scheme employed in conventional models and incorporating the economic value of water. By relying upon economic valuation, the WAMM can support water allocation efforts that focus not only on the stability but also on the economic benefits of water supply. The water supply risk was evaluated following the different objective functions and optimization methods provided by the WAMM using a case study of the Namhan River basin in South Korea under a climate change scenario over the next 30 years. The water shortages and associated economic damage were compared, and the superior ability of WAMM to mitigate future water shortages using economic valuation and full-step linear programming (FSLP) optimization was demonstrated. It is expected that the WAMM can be applied to help resolve water shortages and disputes among river basin units under severe drought conditions.

Water security implications of climate and socio-economic stressors for river basin management

ABSTRACT This study investigated the impacts of climate and socio-economic changes on water resources in the Beas-Sutlej river basin, Himalaya. Multiple-model ensembles of five climate models forced with the Representative Concentration Pathway (RCP) 8.5 scenario and the Shared Socio-economic Pathway SSP 1 were used. A validated Water Evaluation And Planning (WEAP) model of the basin was used for assessing the resulting sectoral water allocations. The results showed increasing runoff during the pre-monsoon and monsoon seasons, principally as the respective consequences of increased glaciers melting and higher rainfall. The finding also indicates that ensemble mean annual irrigation water demand will decrease by between 8 and 13% in Punjab due to the conversion of agricultural land to urban centres but will increase in Rajasthan by about 14%. These outcomes will be useful for the Bhakra and Beas Management Board in developing adaptation strategies to cope with any future water shortages that may occur in the basin.

Tracking Wichita Falls' Path From DPR to IPR

The City of Wichita Falls, Texas, made international news in 2014 when its water system became a water reuse pioneer. In response to a historic drought, the city simultaneously planned and implemented direct potable reuse (DPR) and indirect potable reuse (IPR) systems to see it through the drought and respond to future water shortages. Now, the city is a role model for water utilities around the world.

Forecasting water consumption on transboundary water resources for water resource management using the feed-forward neural network: a case study of the Nile River in Egypt and Kenya

Water resources are an essential component of a country’s natural resource potential. Pressure on these resources is set to increase due to increased water demand, climate change and rainfall variability. This could lead to conflicts between sectoral users, within or between countries, especially among transboundary countries. Interest in transboundary water resources is a priority, especially where issues such as uncertainty regarding the status of transboundary waterbodies and reductions in water volume persist. In this study, we used the feed-forward neural network to forecast water demand along the Nile River in two countries, Egypt and Kenya. Two scenarios were modelled. Input data for the first scenario included preceding records of precipitation, gross domestic product, population and water use in the agricultural sector. The second scenario observed the effects of the growing economy on water resources by doubling the gross domestic product and keeping all other inputs constant. For Kenya, the results projected a steady increase in water demand throughout the next 20 years for both scenarios. However, for Egypt, the observed trend in both scenarios was a decline in water demand, followed by a steady increase. The results underscore the importance of forecasting for easier future planning and management, and to help governing bodies along transboundary water resources develop timely strategies in the future to alleviate future water shortages and poor management of water resources.

Evaluation of policy scenarios for water resources planning and management in an arid region

Study regionAbu Dhabi, United Arab Emirates (UAE) Study focusWater demand in the Emirate of Abu Dhabi (EAD) has increased significantly over the last few decades. Hence, a main challenge for the EAD water policy makers is to develop long-term resilient water resources strategies. This study evaluates future water supply-demand condition in the EAD and identifies water management strategies that support a sustainable future. A dynamic water budget modelling framework is used to evaluate future water demand as affected by population growth, economic growth, proposed water related policies, consumption patterns, and climate change. The Abu Dhabi Dynamic Water Budget Model (ADWBM) is used to construct future water scenarios and assess the status of the EAD water system until 2050 in terms of water supply-demand balance. This study presents four suites of water scenarios, namely: Business as Usual (BAU), Policy First (PF), Sustainability by Conservation (SC), and Rainfall Enhanced Sustainability (RES) scenarios. New hydrological insightsSimulation results indicate that both SC and RES scenarios achieved balanced water budget without any shortage throughout the entire period until 2050. The RES scenario is recommended for adoption because of the reasonable and achievable proposed consumption reductions needed in the different demand sectors. The obtained results should be valuable for devising appropriate strategies to prevent potential future water shortages in the Emirate.

Economic and environmental assessment of water reuse in industrial parks: case study based on a Model Industrial Park

Abstract Industrial wastewater reuse is a major measure to mitigate the depletion of available freshwater resources in the catchments around industrial areas and to prevent possible future water shortages and the resulting problems for industry, economy and society. Combining a set of environmental aspects and economic aspects of different wastewater treatment technologies, the authors developed a model-based approach for planning and evaluating water reuse concepts in industrial parks. This paper is based on an exemplary Model Industrial Park. The results based on data primarily calculated for Germany show that, for the majority of the indicators, the installation of the Water Reuse Plant seems to be beneficial for all examined reuse options. Considering the economic dimension, due to economies of scale, reuse options with larger volumes of treated water are preferable since the costs per m3 of reuse water are reduced by up to 33%. On the other hand, the environmentally preferable option depends on the respective indicator, e.g. for freshwater eutrophication, the higher the reuse factor, the lower the impact, leading to reductions between 8 and 12%. For climate change, the best option is dependent on the reuse purpose leading to reductions between 8 and 52%.

Lessons from the 2018 drought for management of local water supplies in upland areas: A tracer‐based assessment

AbstractClimate change, combined with industrial growth and increasing demand, could result in serious future water shortages and related water quality and temperature issues, especially for upland and humid areas. The extreme 2018 drought that prevailed throughout Europe provided an opportunity to investigate conditions likely to become more frequent in the future. For an upland rural catchment utilised by the distilling industry in North‐East Scotland, a tracer‐based survey combined discharge, electrical conductivity, stable water isotopes and temperature measurements to understand the impacts of drought on dominant stream water and industry water sources, both in terms of water quantity and quality (temperature). Results showed that water types (groundwater, ephemeral stream water, perennial stream water and water from small dams) were spatially distinct and varied more in space than time. With regards to the drought conditions we found that streams were largely maintained by groundwater during low flows. This also buffered stream water temperatures. Water types with high young water fractions were less resilient, resulting in streams with an ephemeral nature. Although our results demonstrated the importance of groundwater for drought resilience, water balance data revealed these storage reserves were being depleted and only recovered towards the end of the following year because of above average rainfall in 2019. Increased storage depletion under continued trends of extreme drought and water abstraction could be addressed via informed (nature based) management strategies which focus on increasing recharge. This may improve resilience to droughts as well as floods, but site specific testing and modelling are required to understand their potential. Results could have implications for management of water volumes and temperature, particularly for the sustainability of an historic industry, balancing requirements of rural communities and the environment.

EFFECTS OF USING SEAWATER IN THE MIXING AND CURING OF CONCRETE

The U.N. evaluates that in 2050 the world population will increase about three point five billion, mostly in evolving countries that have underwent potable water crises. Furthermore, over half of the world population will unable to provide sufficient amounts of drinking water. Consequently, it is absolutely crucial to study ways to save freshwater. The use of seawater, which accounts for 97 percent of all the water present on Earth, is very essential. This thesis studies the use of seawater instead of freshwater in the mixing and curing of structural concrete in order to reduce future water shortage and aid in the evolution of concrete technology. Concrete mixed and cured with seawater is studied in terms of fresh and hardened properties. Results include an expected early accelerated rate of gain in compressive strength and presumably no direct effect on the rate of corrosion of reinforcement when compared to concrete mixed and cured with freshwater. Also, the type of concrete’s effect was studied by using ordinary Portland cement (OPC) and by partial replacement of OPC with Blast-Furnace Slag Cement (BFSC).

Characterizing Hydrological Drought and Water Scarcity Changes in the Future: A Case Study in the Jinghe River Basin of China

The assessment of future climate changes on drought and water scarcity is extremely important for water resources management. A modeling system is developed to study the potential status of hydrological drought and water scarcity in the future, and this modeling system is applied to the Jinghe River Basin (JRB) of China. Driven by high-resolution climate projections from the Regional Climate Modeling System (RegCM), the Variable Infiltration Capacity model is employed to produce future streamflow projections (2020–2099) under two Representative Concentration Pathway (RCP) scenarios. The copula-based method is applied to identify the correlation between drought variables (i.e., duration and severity), and to further quantify their joint risks. Based on a variety of hypothetical water use scenarios in the future, the water scarcity conditions including extreme cases are estimated through the Water Exploitation Index Plus (WEI+) indicator. The results indicate that the joint risks of drought variables at different return periods would decrease. In detail, the severity of future drought events would become less serious under different RCP scenarios when compared with that in the historical period. However, considering the increase in water consumption in the future, the water scarcity in JRB may not be alleviated in the future, and thus drought assessment alone may underestimate the severity of future water shortage. The results obtained from the modeling system can help policy makers to develop reasonable future water-saving planning schemes, as well as drought mitigation measures.

Controlling spherulitic structures at surface and sub-layer of hollow fiber membranes prepared using nucleation agents via triple-orifice spinneret in TIPS process

In this study, the growth of a spherulitic structure at the surface and sub-layer of the polyvinylidene fluoride (PVDF) hollow fiber membrane was controlled by co-extruding nucleation agent (NA) solutions as the outermost layer of a triple-orifice spinneret in the thermally induced phase separation (TIPS) process. Using this method, the spherulites were tailored to be a variety of morphologies having different combinations with the bi-continuous network at the membrane surface and sub-layer, while the bulk membrane structure remained almost unchanged. These typically tailored spherulitic structures dramatically enhanced the surface roughness, hydrophobicity, liquid entry pressure, and permeation stability of the TIPS-prepared PVDF hollow fiber membranes. The experimental results from the pressure-driven filtration and the direct contact membrane distillation demonstrated great potential of the tailored membranes to achieve water treatment and seawater desalination. The electrostatic interaction between NA and PVDF played a key role in tailoring the special membrane spherulite structures, providing new possibilities for engineering TIPS-prepared hollow fiber membranes with desirable structures and performances to address current and future water shortages.

Multi-Objective Optimal Allocation of Urban Water Resources While Considering Conflict Resolution Based on the PSO Algorithm: A Case Study of Kunming, China

With the rapid increase of water demand in urban life, ecology and production sectors, the problem of water resources allocation has become increasingly prominent. It has hindered the sustainable development of urban areas. Based on the supply of various water sources and the water demand of different water users, a multi-objective optimal allocation model for urban water resources was proposed. The model was solved using the algorithm of particle swarm optimization (PSO). The algorithm has a fast convergence and is both simple and efficient. In this paper, the conflict over Kunming’s water resources allocation was taken as an example. The PSO algorithm was used to obtain optimized water resources allocation plans in the year 2020 and 2030, under the circumstances of a dry year (inflow guarantee rate p = 0.825) and an unusually dry year (inflow guarantee rate p = 0.885), respectively. The results showed that those allocation plans can lower the future potential water shortage rates of Kunming. At the same time, the interests of different sectors can all be satisfied. Therefore, conflicts over urban water use can be effectively alleviated.

Projecting China's future water footprint under the shared socio-economic pathways

Increasing water scarcity in China is further exacerbated by the rapid socio-economic development and uneven spatial distribution of water resources. Current studies on water footprint have mainly focused on historical accounting and trend analysis at the provincial scale. However, a comprehensive exploration of future water footprint would be vital to a better understanding of future water shortage challenges, and more importantly, would allow the mitigation of water scarcity and inequal water distribution. In this paper, we present an approach to project the future water footprint of China at a fine resolution (0.125 arc-degree) under the shared socio-economic pathway (SSP) scenario framework, which described five future alternative socio-economic development pathways over the 21st century. We first simulated the future spatial patterns of built-up land using the Future Land Use Simulation (FLUS) model and derived the future population growth and urbanization rate from the population projection provided by the National Center for Atmospheric Research (NCAR). Then future water footprint was projected according a log-transformed linear regression calibrated with historical data during 2007–2012. We found that the total volume of China's water footprint will increase significantly in the future under the SSP1, SSP4 and SSP5 scenarios, reaching up to nearly 400 billion m3 in 2050, equivalent to almost 40% increase compared to that in 2010. The spatial patterns of future water footprint show dramatic increase (up to 100–130%) in the eastern provinces (Shandong, Henan, and Hebei), and slight decrease were found in the western provinces (Xinjiang, Ningxia, and Qinghai). In addition, the future water footprints were found to share very similar spatial patterns at local pixel scale among different SSP scenarios in three of the largest metropolitan areas of China (Beijing-Hebei-Tianjin, Yangtze River Delta, and Pearl River Delta). These findings provide extensive knowledge of the future water footprint and suggest a more severe water scarcity in the future from a consumption-oriented perspective. More effective water management policies are urgently needed to mitigate future water resource scarcity and inequality.

Water Resources Allocation Systems under Irrigation Expansion and Climate Change Scenario in Awash River Basin of Ethiopia

Rational allocation of water resources is very essential to cope with water scarcity. The optimal allocation of limited water resources is required for various purposes to achieve sustainable development. The Awash River Basin is currently faced with a scarcity of water due to increasing demands, urbanization, irrigation expansion, and variability of climates. The excessive abstraction of water resources in the basin without proper assessing of the available water resources contributed to water scarcity. This paper aimed to develop a water evaluation and planning (WEAP) model to allocate the water supplies to demanding sectors based on an economic parameter to maximize the economic benefits. The water demands, water shortages, and supply alternatives were analyzed under different scenarios. Three scenarios were developed, namely reference (1981–2016), medium-term development (2017–2030), and long-term development (2031–2050) future scenarios with the baseline period (1980). The results of this study showed that the total quantity of water needed to meet the irrigation demands of all the stations was 306.96 MCM from 1980 to 2016. Seasonally, March, April, May, and June require the maximum irrigation water demand. However, July, August, and September require minimum demand for water because of the rainy season. The seasonal unmet demand is observed in all months, which ranged from 6 × 106 m3 to 35.9 × 106 m3 in August and May respectively. The trend of streamflow in Melka Kuntre was a statistically significant increasing trend after 2008 (Z = 5.33) whereas the trends in other gauge stations showed a relatively decreasing trend. The results also showed that future water consumption would greatly increase in the Awash River Basin. The prevention of future water shortages requires the implementation of water-saving measures and the use of new water supply technologies. The findings of this study will serve as a reference for water resources managers and policy and decision makers.

Integrated numerical model for irrigated area water resources management

Abstract The likelihood of future global water shortages is increasing and further development of existing operational hydrologic models is needed to maintain sustainable development of the ecological environment and human health. In order to quantitatively describe the water balance factors and transformation relations, the objective of this article is to develop a distributed hydrologic model that is capable of simulating the surface water (SW) and groundwater (GW) in irrigation areas. The model can be used as a tool for evaluating the long-term effects of water resource management. By coupling the Soil and Water Assessment Tool (SWAT) and MODFLOW models, a comprehensive hydrological model integrating SW and GW is constructed. The hydrologic response units for the SWAT model are exchanged with cells in the MODFLOW model. Taking the Heihe River Basin as the study area, 10 years of historical data are used to conduct an extensive sensitivity analysis on model parameters. The developed model is run for a 40-year prediction period. The application of the developed coupling model shows that since the construction of the Heihe reservoir, the average GW level in the study area has declined by 6.05 m. The model can accurately simulate and predict the dynamic changes in SW and GW in the downstream irrigation area of Heihe River Basin and provide a scientific basis for water management in an irrigation district.