Alleviate Water Scarcity Research Articles

Alleviating water scarcity and poverty through water rights trading pilot policy: A quasi-natural experiment based approach

Water poverty is among the most significant global challenges and severely restricts the sustainable development of societies and economies, especially in the world's arid regions. Many countries have attempted to address this challenge. Market-based trading mechanisms represent an essential method of resolving the problem of water shortages and alleviating water poverty. Based on a quasi-natural experiment of water rights trading pilots in China, this study uses panel data from 31 provinces (municipalities) from 2009 to 2019 to explore the impact of water rights trading pilot policy on water poverty through a difference-in-differences (DID) model. The research results show that such policies can effectively alleviate water poverty by improving water-saving irrigation technology, promoting industrial and agricultural water trading, and optimizing the industrial structure. Additionally, dynamic effect and spatial heterogeneity analyses show that the water rights trading pilot policy have long-term effects and have a stronger mitigation effect on the western region of China compared with the central and eastern regions. Therefore, the Chinese government should not only further expand the implementation scope of these policies but also adjust measures according to local conditions to accurately and effectively implement such policies in different regions. Our study provides insights into water policies in China that can better manage natural resources and reduce water poverty in the arid areas around the world.

Risk and reward of the global truffle sector under predicted climate change

Climate change has been described as the main threat for the cultivation and growth of truffles, but hydroclimate variability and model uncertainty challenge regional projections and adaptation strategies of the emerging sector. Here, we conduct a literature review to define the main Périgord truffle growing regions around the world and use 20 global climate models to assess the impact of future trends and extremes in temperature, precipitation and soil moisture on truffle production rates and price levels in all cultivation regions in the Americas, Europe, South Africa, and Australasia. Climate model simulations project 2.3 million km2 of suitable land for truffle growth will experience 50% faster aridification than the rests of the global land surface, with significantly more heat waves between 2070 and 2099 CE. Overall, truffle production rates will decrease by ∼15%, while associated price levels will increase by ∼36%. At the same time, a predicted increase in summer precipitation and less intense warming over Australasia will likely alleviate water scarcity and support higher yields of more affordable truffles. Our findings are relevant for truffle farmers and businesses to adapt their irrigation systems and management strategies to future climate change.

Biomaterial amendments combined with ridge–furrow mulching improve soil hydrothermal characteristics and wolfberry (Lycium barbarum L.) growth in the Qaidam Basin of China

Droughts, intense soil evaporation, and poor soil structure with low water holding capacity and nutrients restrict agricultural production in the Qaidam Basin on the Tibetan Plateau. Excessive chemical fertilizers have been applied to increase the yields of wolfberry (Lycium barbarum L.), a significant economic crop in northwest China, which has further degraded soils. Biomaterial amendments and ridge–furrow mulching are effective measures for increasing soil water availability, crop yields, and water use efficiency (WUE). However, the combined effects of biomaterial amendments and ridge–furrow mulching on soil hydrothermal conditions, crop growth, and yield in this area are unknown. A field study was undertaken in 2018 and 2019 to investigate their combined influences on soil moisture and temperature, crop growth, yield characteristics, and WUE on the Tibetan Plateau. The experiment comprised four treatments: flat planting with film mulching (FM), flat planting with film mulching and biomaterial amendment (FMBA), ridge–furrow planting with film mulching (RM), and ridge–furrow planting with film mulching and biomaterial amendment (RMBA). The biomaterial amendment and ridge–furrow mulching treatments increased soil water content in the 0–120 cm soil layer, especially at 0–60 cm soil depth at early growth stages, compared with FM. Furthermore, the ridge–furrow mulching treatments had significantly higher soil temperatures than the FM treatment at the sprout stage. The RMBA treatment produced favorable soil hydrothermal properties, which significantly increased mean plant height, ground diameter, and root length density (RLD). The RMBA treatment also produced the highest crop yield, WUE, and berry quality in both growing seasons. Compared with FM, the RMBA treatment increased mean yield and WUE by 23.0% and 28.6%, respectively, across the two growing seasons. We conclude that the RMBA treatment is an effective and promising cultivation pattern for alleviating water scarcity and improving soil hydrothermal conditions, yield, and WUE on the Tibetan Plateau.

Neo - Pentecostal Churches Advocacy and Alleviation of Domestic Water Scarcity in Tigania West Constituency, Meru County, Kenya

Most neo-Pentecostal churches contravene Luke 4:16-19, Psalms 41 and Exodus 18: 21 by failing to advocate for peoples’ water rights. This stance has of late interested many scholars to do studies on churches and advocacy for water rights. In line with this, this study analyzed such advocacy by neo - Pentecostal churches in alleviating domestic water scarcity in Tigania West Constituency, Meru County, Kenya. The objectives were to: investigate how neo- Pentecostal churches advocated for water rights on their own, assess how Neo-Pentecostal churches partnered with other water advocacy groups, and, investigate how neo-Pentecostal churches supported politicians for the alleviation of this menace. Theological reflection theory, interpretivist philosophy, qualitative approach and phenomenological design guided this study. The sample entailed 22 pastors taken through census, and 59 out of 594 members belonging to these pastors’ 22 churches, taken through 10% in the 10-30 % formula. This was followed by cluster and simple random samplings. Tools used on them were interview schedule for the 22 pastors, documentary analysis for their churches, and  focus group discussions for the 59 members held in 4 groups of 12 members each and 1 group of 11 members. Data collected was purely qualitative and was analyzed using interpretive phenomenological analysis. The findings indicated that these churches did not engage in advocacy for water rights. But, they agreed that they supported ‘good’ political leaders to win elections so as to help in alleviating domestic water scarcity. The study recommended that training actors should organize premises to train neo–Pentecostal Churches on advocacy for water rights. This would orient the latter to social gospel and thus push for advocacy for water rights and the best practices in electing political leaders to alleviate water scarcity in the constituency. Key terms: Neo-Pentecostals churches, advocacy or water rights, domestic water scarcity, ecclesiastical praxis

Environmental rethinking of wastewater drains to manage environmental pollution and alleviate water scarcity.

The conservation of water resources in developed countries has become an increasing concern. In integrated water resource management, water quality indicators are critical. The low groundwater quality quantitates mainly attributed to the absence of protection systems for polluted streams that collect and recycle the untreated wastewater. Egypt has a limited river network; thus, the supply of water resources remains inadequate to satisfy domestic demand. In this regard, high-quality groundwater is one of the main strategies for saving water supplies with water shortage problems. This paper investigates the critical issues of groundwater protection and environmental management of polluted streams, leading to overcoming water demand-about 18 × 103 km of polluted open streams with a discharge of 9.70 billion Cubic Metter (BCM). We have proposed proposals and policies for the safe use of groundwater and reuse of wastewater recycling for agriculture and other purposes. This study was carried out using the numerical model MODFLOW and MT3DMS—(Mass Transport 3-Dimension Multi-Species) to assess the Wastewater Treated Plant's (WWTP) best location and the critical path for using different lining materials of polluted streams to avoid groundwater contamination. The three contaminants are BOD, COD, and TDS. Five scenarios were applied for mitigating the impact of polluted water: (1) abstraction forcing, (2) installing the WWTP at the outlet of the main basin drain with and without a lining of main and sub-basin streams (base case), (3) lining of main and sub-main streams, (4) installing WWTP at the outlet of the sub-basin streams, and (5) lining of the sub-basin and installing WWTP at the outlet of the sub-basin. The results showed that the best location of WWTP in polluted streams is developed at the outlets of sub-basin with the treatment of main basin water and the lining of sub-basins streams. The contamination was reduced by 76.07, 76.38, and 75.67% for BOD, COD, and TDS, respectively, using Cascade Aeration Biofilter or Trickling Filter, Enhancing Solar water Disinfection [(CABFESD)/(CATFESD)] and High-Density Polyethylene lining. This method is highly effective and safe for groundwater and surface water environmental protection. This study could be managing the water poverty for polluted streams and groundwater in the Global South and satisfy the environmental issues to improve water quality and reduce the treatment and health cost in these regions.

Future virtual water flows under climate and population change scenarios: focusing on its determinants

Abstract Water resources are under increasing pressure from population growth, socio-economic development, and climate change. The main user of freshwater is the agriculture sector, accounting for 70–80% of global water use. Consequently, increasing water productivity and reducing water use in this sector are vital for alleviating water scarcity. It has been alleged that domestic or international trade of water-consumed products from wet-provinces or countries to arid and semi-arid provinces or countries is one possible path to mitigate water shortage. In this regard, virtual water flows and their determinants in Iran are investigated in this paper. This study examines the main determinants of bilateral virtual water flows associated with international trade in agricultural goods among Iran and other countries using a gravity model of trade. The impacts of climate change and socio-economic change scenarios on the virtual water trade are simulated. The result of the gravity model indicated that bilateral virtual water trade flows are influenced by the classical determinants and all the mass-related variables (gross domestic product and population) are significant with expected signs. Finally, the result obtained from the simulation of climate and socio-economic change scenarios showed that under the pessimistic scenario of climate change and population growth rate of 0.98 and 0.44%, VW trade between Iran and other countries would increase by 41 and 66% in the periods of 2016–2045 and 2070–2099, respectively. As a consequence, identifying the appropriate countries for business interactions and adopting effective trade policies are very important and need attention soon.

Surface modification of nanofiltration membranes with zwitterions to enhance antifouling properties during brackish water treatment: A new concept of a “buffer layer”

Nanofiltration (NF)-based brackish water desalination has been labeled an emerging avenue for alleviating water scarcity, however, membrane fouling still restricts its broad application. Herein, zwitterion-modified membranes were prepared with polydopamine (PDA) and sulfobetaine methacrylate (SBMA) monomers via surface-initiated atom-transfer radical-polymerization (SI-ATRP) and named TFC-PDA-PSBMA. Compared with the control membrane, the TFC-PDA-PSBMA possessed enhanced hydrophilicity, lower negative charge and smaller pore size. Superior salt retention of Na2SO4 and NaCl of up to 99.1% and 80.7% was obtained for TFC-PDA-PSBMA with only a 10% decrease in permeance. Furthermore, TFC-PDA-PSBMA exhibited an outstanding flux recovery of 92.1% during humic acid (HA) filtration. The mechanism driving the improved antifouling properties was analyzed from the aspects of the modified layer, free interfacial energy and hydration layer. TFC-PDA-PSBMA also exhibited superior antibiofouling with reducing 86.1% of E. coli colonies adhered on membrane surface. The SBMA layer and hydration layer acted together as a buffer layer with robust repulsion of foulants. In addition, the TFC-PDA-PSBMA membrane was applied in authentic brackish water desalination and exhibited superior selectivity, desalination and antifouling performance, which matched the simulated solution results well. A new concept of a “buffer layer” was proposed in this work, which may provide insight into antifouling membrane design during brackish water treatment.

A factorial emission-focused general equilibrium model for investigating composite effects of multiple environmental policies

With the rapid growth of the economy, there are increasing conflicts between economic development and environmental protection. Among these conflicts, the wastewater emission management as one of the significant ways to alleviate water scarcity has been paid increasing attention across the developing countries, such as China. It is thus essential to comprehensively investigate the enviro-economic effects induced by wastewater-related policies. In this study, a factorial emission-focused general equilibrium model (FEGE) is first developed to facilitate examine the composite enviro-economic effects of multiple policy scenarios with regards to wastewater-related environmental taxes and the related subsides. A special case study for the Municipality of Chongqing, China, is conducted to illustrate the potential benefits of its use in the formulation of wastewater-related policies. It is found that the impacts of various wastewater-related policies (i.e., environmental taxes and the related subside) on GDP are different. In detail, green tax policies on GDP are negative, while wastewater emission intensity (WEI) improvement policies on GDP are positive. When green tax reaches 14 yuan/tonne, which is the maximum proposed by the Chinese government, the GDP will drop by 0.37%, which would be deemed acceptable for the Municipality of Chongqing. In addition, the impacts on rural households’ consumption are greater than those on urban households’ consumption whichever the application of wastewater-related policies; it is because the rural households in the Municipality of Chongqing have a relatively unitary income source. It is thus recommended that the rural household in Chongqing should be paid more attention. For example, some extra allowances could be considered to the rural household to help them cope with the negative economic impacts induced by a new environmental policy. It is expected that the outputs would provide bases for formulating desired wastewater-related policies.

Future Irrigation Water Requirements of the Main Crops Cultivated in the Niger River Basin

Precise agricultural predictions of climate change effects on crop water productivity are essential to ensure food security and alleviate water scarcity. In this regard, the present study provides an overview of the future impacts of climate change on the irrigation of agricultural products such as rice, millet, maize, cassava, sorghum, and sugar cane. These crops are some of the most-consumed foodstuffs in countries of the Niger River basin. This study is realized throughout 2020 to 2080, and three Global Climate Models (GCMs) (CSIRO, MIROC5, and ECHAM. MPI-ESM-LR) have been used. The GCMs data have been provided by the IPCC5 database. The irrigation water requirement for each crop was calculated using Smith’s CROPWAT approach. The Penman–Monteith equation recommended by the FAO was used to calculate the potential evapotranspiration. The inter-annual results of the IWR, according to the set of models selected, illustrate that the largest quantities of water used for irrigation are generally observed between January and March, and the lowest quantities are the most often seen between July and September. The majority of models also illustrate a peak in the IWR between March and April. Sorghum and millet are the crops consuming the least amount of water for irrigation; followed by cassava, then rice and corn, and finally sugar cane. The most significant IWRs, which have been predicted, will be between 16.3 mm/day (MIROC5 model, RCP 4.5) and 45.9 mm/day (CSIRO model, RCP 4.5), particularly in Mali, Niger, Algeria, and rarely in Burkina-Faso (CSIRO model, RCP4.5 and 8.5). The lowest IWRs predicted by the models will be from 1.29 mm/day (MIROC5 model, RCP 4.5) to 33.4 mm/day (CSIRO model, RCP 4.5); they will be observed according to the models in Guinea, southern Mali, Ivory Coast, center and southern Nigeria, and Cameroon. However, models predict sugarcane to be the plant with the highest IWR, between 0.25 mm/day (Benin in 2020–2040) and 25.66 mm/day (Chad in 2060–2080). According to the models’ predictions, millet is the crop with the most IWR, between 0.20 mm/day (Benin from 2020 to 2060) and 19.37 mm/day (Chad in 2060–2080). With the results of this study, the countries belonging to the Niger River basin can put in place robust policies in the water resources and agriculture sectors, thus ensuring food security and high-quality production of staple crops, and avoiding water scarcity while facing the negative impacts of climate change.

Hydrophilic slippery surface enabled coarsening effect for rapid water harvesting

Summary Water harvesting through the condensation of vapor in air has the potential to alleviate water scarcity in arid regions around the globe. When water vapor is condensed on a cooled surface, tiny water droplets act as thermal barriers. Thus, they must be removed rapidly for efficient water harvesting. Passive technologies for droplet removal rely on in-site growth and direct contact of densely distributed droplets. However, it is challenging to remove submicrometer droplets that lead to a poor water harvesting rate. Here, we present a coarsening effect to rapidly remove water droplets with diameters

Unraveling the effect of inter-basin water transfer on reducing water scarcity and its inequality in China

Securing water supply in the face of increasing water scarcity is one important challenge faced by humanity in sustainable development. Inter-basin water transfer is widely applied to provide water supply security in regions where water demand exceeds water availability. However, the effect of inter-basin water transfer on alleviating water scarcity and its inequality is poorly understood especially at the national scale. Based on a newly compiled database of inter-basin water transfer projects in China, here we report a first national assessment of their effect on securing water supply in different basins. We developed a number of indices to facilitate quantifying the effect of water transfer on water scarcity and its inequality. The capacity of inter-basin transfer projects has been steadily increased, which achieved ~48.5 billion m3 yr−1 by 2016 (equivalent to ~8% of the national water use). The results indicate that water transfer has impacted water supply of 43 sub-basins out of a total of 76 sub-basins, but it hardly changes a basin's water scarcity level (e.g., from water scarcity to low water scarcity). Approximately three quarters of people in China are affected by water transfer. More than a half of the national population (705 million) benefit from alleviated water scarcity, leading to the inequality coefficient reduced from 0.64 under natural water availability condition to 0.59 considering water transfer in 2016. However, 357 million people in water transfer source basins are subject to increased water scarcity, in which ~21% are from water stressed sub-basins. This study reveals for the first time water transfer induced water scarcity and inequality change across sub-basins in China, and highlights the challenges to secure water supply across basins.

Machine-Learning-Assisted Autonomous Humidity Management System Based on Solar-Regenerated Super Hygroscopic Complex.

High levels of humidity can induce thermal discomfort and consequent health disorders. However, proper utilization of this astounding resource as a freshwater source can aid in alleviating water scarcity. Herein, a low‐energy and highly efficient humidity control system is reported comprising of an in‐house developed desiccant dehumidifier and hygrometer (sensor), with an autonomous operation capability that can realize simultaneous dehumidification and freshwater production. The high efficiency and energy saving mainly come from the deployed super hygroscopic complex (SHC), which exhibits high water uptake (4.64 g g−1) and facile regeneration. Machine‐learning‐assisted in‐house developed low cost and high precision hygrometers enable the autonomous operation of the humidity management system. The dehumidifier can reduce the relative humidity (RH) of a confined room from 75% to 60% in 15 minutes with energy consumption of 0.05 kWh, saving more than 60% of energy compared with the commercial desiccant dehumidifiers, and harvest 10 L of atmospheric water in 24 h. Moreover, the reduction in RH from 80% to 60% at 32 °C results in the reduction of apparent temperature by about 7 °C, thus effectively improving the thermal comfort of the inhabitants.

Experimental and numerical investigation of a new hollow fiber-based multi-effect vacuum membrane distillation design

Distillation systems can achieve much higher energy efficiency by utilizing multiple effects to internally recycle latent heat. Flat sheet membrane distillation systems (i.e., the Memsys MDS range of products) have taken advantage of this, but hollow fiber vacuum membrane distillation systems have not yet been systematically designed to incorporate the multi-effect concept. To advance this concept, a hollow fiber-based multi-effect VMD (HF V-MEMD) was designed and manufactured to internally recover the latent heat of the permeate vapor between effects using hollow helical baffles. A mathematical model was developed to investigate the effect of the operating and design conditions on the permeate flux, the gained output ratio (GOR), and the specific total energy consumption (STEC). It was found that a GOR of 1.5–3.5 can be achieved across a range of operating conditions. Additionally, for an optimal module design (e.g., 500 m2/m3 packing density, 0.5 m module length, and a 0.2–0.3 m shell diameter), the results indicate that a 4-effect design can improve the STEC by more than 60% compared to a single-effect design. Overall, this study concludes that the proposed energy-efficient HF V-MEMD design is most suitable for compact, portable systems to alleviate water scarcity in rural arid-regions.

The Impacts of Arable Land per Farmer on Water Markets in China

Water trading markets have been introduced in many countries as a means to alleviate water scarcity. However, the performance of water markets varies greatly across different countries, and in only very few countries do they work well. In this study, a two-sector water rights trading model is developed and applied to a case study in China. The results suggest that arable land per farmer is a key factor that affects the performance of water markets in China. This is positively correlated with traded water volume, with the market’s economic efficiency, and with the social welfare the market brings. Although the model simulation ignores other factors, this problem can be solved by selecting a suitable research area. These findings suggest that water markets may be less likely to be effective in countries with small arable land per farmer.

Evaluation of the most proper management scale on water use efficiency and water productivity: A case study of the Heihe River Basin, China

Increasing agricultural water use efficiency (WUE) and water productivity (WP) is imperative to alleviate water scarcity and achieve sustainable agriculture in inland river basins. The confusion on the use of the two indicators at demarcated scales in this issue has been addressed. Analysis of the literature, however, lacks evaluation of the most proper management scale. The Heihe River Basin (HRB) in China was selected as the study area and WUE and WP were calculated spatially at the field crop, irrigation district, and county scales using the remote sensing-based evapotranspiration (ET), grid rainfall, land use, and statistical data. In addition, the most proper management scale was firstly evaluated by comparing WUE and WP based on statistical properties and spatial distributions. The results show that higher WUE and WP were observed at the field crop scale. The differences between WUE and WP are significant at field crop scale but the gap narrows with increasing spatial scale. Spatial analysis reveals that WP was higher in the plain oasis area and lower in the mountainous and desert oasis area. Among three scales, the WUE and WP are relatively lower and the variances of them are relatively larger at the irrigation district scale. WUE ranges from 0.1 to 0.85 (mean 0.34) and WP varies from 0.08 kg/m3 to 0.8 kg/m3 (mean 0.48 kg/m3) across irrigation districts in the whole basin. The large differences indicate the presence of a tremendous management gap among irrigation districts. We thus declare that mesoscale views are more suitable and irrigation district scale is the most proper management scale for resolving water resource utilization problems in arid river basins. Further, agricultural water management at the irrigation district scale should target at improving irrigation technology and adjusting crop structure.

A seca e seus desdobramentos: reflexões a partir da realidade da Microrregião de Pau dos Ferros

A região Nordeste sempre foi vista como a região da seca, do subdesenvolvimento, do homem desamparado e de diversos outros estereótipos que consagraram a caracterização de sua configuração humana, econômica e espacial pelas outras regiões do país. A ausência de água é um aspecto marcante, que além de flagelar o nordestino, é utilizada como aporte político para muitos representantes governamentais adotarem discursos de “solução à seca” com a finalidade de adquirirem apoio popular. O objetivo deste trabalho é apresentar a perda de importância das atividades rurais na microrregião de Pau dos Ferros/RN e discutir as medidas emergenciais adotadas para amenizar a escassez de água com ênfase neste município. Para tanto, foi realizado levantamento de dados com foco nas variáveis População e Produto Interno Bruto Agropecuário, extraídos das bases de dados do IBGE; coletados dados na Secretaria de Desenvolvimento Rural de Pau dos Ferros/RN; e realizadas buscas acerca da questão hídrica deste município em portais online. Diante disso, o que se observou foi a relativa perda de participação do PIB agropecuário na composição do PIB Municipal, redução da população rural nessa microrregião e a implantação de ações paliativas de combate à seca.

Building climate resilience in degraded agricultural landscapes through water management: A case study of Bundelkhand region, Central India

Rainfall variability and water scarcity continue to hamper the food and income security of smallholder farming systems in poverty-affected regions. Innovations in soil and water management, especially in the drylands, are critical for meeting food security and water productivity targets of Agenda 2030. This study analyzes how rainfed agriculture can be intensified with marginal impact on the landscape water balance. The impact of rainwater harvesting structures on landscape hydrology and associated agricultural services was analyzed in the semi-arid Jhansi district of Bundelkhand region in central India. The Parasai-Sindh pilot watershed was subjected to a 5-year (2012–2016) monitoring of rainfed system improvements in water availability and crop intensification due to surface water storage (haveli system), check dams, and field infiltration structures. Hydrological processes were monitored intensively to analyze the landscape’s water balance components. Rainwater harvesting (RWH) structures altered the landscape’s hydrology, limiting average surface runoff from 250 mm/year to 150 mm/year over the study period. Groundwater levels increased by 2–5 m (m), alleviating water scarcity issues of the communities in recurring dry years. Nearly 20% of fallow lands were brought under cultivation. Crop yields increased by 10–70% and average household income increased from US$ 960/year to US$ 2700/year compared to that in the non-intervention landscape. The combined soil–water–vegetation efforts strengthened water resilience and environmental systems in agricultural landscape.

A participatory methodology for characterizing and prescribing water-energy-food nexus based on improved casual loop diagrams

As the basis of quantitative research over water-energy-food nexus (WEFN), qualitative analysis is indispensable for depicting the systems and providing effective measures and policies. Preceding qualitative WEFN studies largely neglected the role of local stakeholder participation, which could only reflect fragments of the systems. Causal loop diagrams (CLDs) have been proven to be effective for supporting stakeholder participation in many other areas. Nevertheless, there was a lack of impartial methods that could make CLD analysis tractable without significantly impairing the WEFN systems integrity. To fill such gaps, a novel method based on merging and reduction rules was proposed to reasonably merge and downscale WEFN CLDs built by stakeholders. Based on this improved method, a CLD-based methodology was developed as a prototype for characterizing WEFN systems, prescribing the WEFN problem, exploring its causes and consequences, and identifying effective measures and policies for alleviating conflicts. To validate the applicability of the developed methodology, it was applied to a real case. The results indicated that total water consumption, water allocation among varied sectors, available surface water, and available groundwater, as well as indirect factors such as volume of diverted water and agricultural water consumption, were the keys to alleviate water scarcity problem under WEFN in the study area. Measures and polices focusing on the interactions between surface water and groundwater could be viable for alleviating the problem. Directions to enhance tradeoffs and synergies within WEFN systems were also obtained.

A multi-source virtual water metabolism model for urban systems

Increasing industrialization and urbanization stress on water resources in the world. It is crucial to analyze urban virtual water metabolism systems comprehensively to uncover economic water flow reduction pathways to support maintainable development. In this study, a multi-source virtual water metabolism (MVWM) model is developed for Chongqing City to facilitate distributive analysis of the interactive effects from multiple water sources on urban systems. In addition, three disaggregated types of water sources (surface water, groundwater, and other water) are examined with their distributive features in relation to virtual and physical water shortages being highlighted among multiple sectorial users. The system’s health condition is monitored by integrating ecological network analysis (ENA) and input-output analysis (IOA). Results illustrate that the groundwater system in Chongqing is relatively healthy and can be exploited appropriately, while the surface water system has higher water stress. Direct water consumptions are mostly happened in primary industries, while indirect water consumptions are most likely to occur in secondary and tertiary industries. Based on ecological hierarchy analysis, Advanced Manufacturing (AM) has large pulling and driving force simultaneously, which denotes that AM is very important for the whole economic system of Chongqing. Besides, some typical industries with damaging relationships are identified based on ecological network utility analysis to alleviate water scarcity, such as construction, mining and washing of coal, as well as manufacture of foods and processing of tobacco.

Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia

Study regionLake Ziway sub-basin, Central Rift Valley basin, Ethiopia. Study focusThis study evaluated the applicability of the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) and the Coordinated Regional Downscaling Experiment (CORDEX-AFRICA) datasets for climate change impact assessment. It also evaluated the hydrologic impact of climate change in the sub-basin. The hydrologic model Soil and Water Assessment Tool (SWAT) was forced with the climate datasets to simulate the reference and future period streamflows under RCP 4.5 and RCP 8.5 scenarios. The seasonality and volumetric deviations of the average annual streamflows simulated using the climate models were used as criteria for selecting members of the ensemble. New hydrological insights for the regionAll the climate models in the bias-corrected NEX-GDDP datasets failed to satisfy the criteria. The ensemble average annual streamflows, simulated using the CORDEX-AFRICA dataset, are expected to increase towards the end of the century under both the climate scenarios. However, the ensemble average dry season streamflows are projected to decrease during the mid- and end-periods of the century. The expected decreases in streamflows during the dry and pre-wet seasons, along with excessive abstractions of water from Lake Ziway, would exacerbate water scarcity in the basin. Approaches need to be developed to capture the increase in water availability during the wet season to alleviate water scarcity during the dry season.