Alleviate Water Scarcity Research Articles

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.

Implementing Sustainable Irrigation in Water-Scarce Regions under the Impact of Climate Change

The sustainability of irrigated agriculture is threatening due to adverse climate change, given future projections that every one in four people on Earth might be suffering from extreme water scarcity by the year 2025. Pressurized irrigation systems and appropriate irrigation schedules can increase water productivity (i.e., product yield per unit volume of water consumed by the crop) and reduce the evaporative or system loss of water as opposed to traditional surface irrigation methods. However, in water-scarce countries, irrigation management frequently becomes a complex task. Deficit irrigation and the use of non-conventional water resources (e.g., wastewater, brackish groundwater) has been adopted in many cases as part of a climate change mitigation measures to tackle the water poverty issue. Protected cultivation systems such as greenhouses or screenhouses equipped with artificial intelligence systems present another sustainable option for improving water productivity and may help to alleviate water scarcity in these countries. This article presents a comprehensive review of the literature, which deals with sustainable irrigation for open-field and protected cultivation systems under the impact of climatic change in vulnerable areas, including the Mediterranean region.

Alleviating water scarcity and poverty in drylands through telecouplings: Vegetable trade and tourism in northwest China

Water scarcity and poverty are among the most significant global challenges, especially in the world's arid regions. Many countries have been trying to address these challenges. Facilitated by the construction of infrastructure (e.g., high-speed rails) and development of services industries (e.g., hotels and resorts), telecouplings (human-nature interactions over distances, e.g., vegetable trade and tourism industry) are expected to alleviate both water scarcity and poverty, and have been much supported by the central government of China. However, the extent to which these telecouplings can save water and reduce poverty remains unclear and requires quantification. Employing the simulated results from an integrated hydrological model, crop growth model, and multiple socioeconomic data from a large arid region of northwest China, the Heihe River Basin, we evaluated water scarcity using a composite index that considered both water resources and poverty between 2000 and 2012, and assessed the effects of the vegetable trade and tourism on water scarcity and income. Our results show that the vegetable trade contributed 30% of the total water saving and brought an extra 33% of income to rural residents. The tourism industry's contribution of saving water increased from 1% of its total water use in 2000 to 22% in 2012 through its ongoing expanding market. Our results also implicate that future water sustainability is determined by climate factors and by social factors, such as population, economy, policy, and technological developments. Our study provides insights into northwest China and can be used to develop arid regions around the world to better manage natural resources and reduce poverty.

Governmental Options to Regulate Water Scarcity: What Can the Law Offer?

Governments all around the world have to decide on how to combat the coming water crisis. In our contribution, we analyze what the law has to offer in controlling the problem of water scarcity and fostering sustainable irrigation, the equity of water allocation, and control over environmental impacts. The main question is: “What are the governmental options to regulate water scarcity via legislation and how to become fit for the future?” Based on the theoretical framework of environmental economics, we will describe four types of possible regulation to deal with water scarcity: command and control regulation, incentive-based regulation, the supply of information, and nudges or paternalistic regulation. All these types of regulations can be used to achieve the same goal: combating water scarcity. Subsequently, based on this typology, we will review several European and non-European examples to see how supra-national and national governments are undertaking action to alleviate water scarcity, by either reducing the need for freshwater or increasing the availability of freshwater. These examples can inspire other countries around the world who are considering new forms of regulation. The examples also show that those governments are already inspiring each other; new forms of European regulation on reusing wastewater for agricultural irrigation are inspired by examples all over the world, including the Australia, the United States and India. One clear conclusion when reviewing the strategies across several countries is that the problem remains insufficiently recognized, and is therefore not as high as it should be on the political and scientific agenda. Even worse, as we will highlight, some legal frameworks have the unintended effect of creating obstacles against innovative projects which can alleviate water scarcity, and therefore the current framework of regulation functions as an impediment to preventing or solving the issue. After presenting an overview of the theory and practice, and drawing conclusions, we conclude our contribution with an overview of the questions to be considered when formulating new regulations, and three recommendations to make the regulatory framework fit for the future.

Interprovincial food trade and water resources conservation in China

A spatial mismatch in water and arable land availability results in large virtual water transfers through interprovincial food trade in China. Accurately identifying and measuring water-saving links in interprovincial food trade can help to relieve water resources pressure in main grain-producing areas. We use a multiregional input-output table combined with the CROPWAT model to build China's interprovincial virtual water transfer network embedded in food trade in 2012. Then, water saving and scarce water saving are measured. Both consider the difference in water productivity among provinces, but the latter also pays attention to the scarcity of water resources. Finally, we adopt a water footprint to recalculate the scarce water savings without precipitation (green water). Our results indicate that the amount of virtual water transfer embedded in food trade is 74.9 billion m3, which is equivalent to 12.22% of the total water use in 2012. We observe large variations in the relationship between water resources abundance and agricultural water-use efficiency across provinces. Especially, there is a virtual water transfer from provinces with high water productivity but a lack of water to provinces with low water productivity but an abundance of water. The scarce water saving can identify sustainable food trade links, which can alleviate water scarcity in consuming provinces without exacerbating water shortage in producing provinces. In addition, interprovincial food trade results in 15 billion m3 of scarce gray water saving, which is equivalent to 59.76% of the scarce blue water saving. Scarce water saving based on blue water and gray water provides a basis for establishing an interprovincial compensation mechanism to balance the cost of water redistribution caused by food trade.

The globalization of virtual water flows: Explaining trade patterns of a scarce resource

Abstract Water availability is paramount for security and development, yet many countries suffer from water scarcity. Virtual water trade, or trade in water- embedded agricultural commodities, has been considered a means for countries to overcome water deficits provided they can import food rather than produce locally. Despite a rich literature, research on the subject has not reached a consensus on whether virtual water trade is actually driven by relative water endowment differentials (e.g. countries seeking to alleviate pressure on their own resources) or by comparative advantage in water utilization (e.g. countries using their most abundant and cheap factors of production). Understanding what drives virtual water trade would support water management policies in targeting the roots of water depletion: excessive use due to lack of other available inputs and bad water management due to absence of water use regulation. Using panel data of bilateral virtual water trade flows from 1994 to 2007 applied to a gravity model, we first demonstrate that arid countries do resort to trade as a means to alleviate water scarcity. Second, we demonstrate that there is much inefficiency in water use in some countries where other agricultural inputs (land, labor) are available and cheap. Given the increased urgency related to global water scarcity, our results suggest how agricultural production and trade could help countries preserve and better use precious water resources.

Water scarcity and fish imperilment driven by beef production

Human consumption of freshwater is now approaching or surpassing the rate at which water sources are being naturally replenished in many regions, creating water shortage risks for people and ecosystems. Here we assess the impact of human water uses and their connection to water scarcity and ecological damage across the United States, identify primary causes of river dewatering and explore ways to ameliorate them. We find irrigation of cattle-feed crops to be the greatest consumer of river water in the western United States, implicating beef and dairy consumption as the leading driver of water shortages and fish imperilment in the region. We assess opportunities for alleviating water scarcity by reducing cattle-feed production, finding that temporary, rotational fallowing of irrigated feed crops can markedly reduce water shortage risks and improve ecological sustainability. Long-term water security and river ecosystem health will ultimately require Americans to consume less beef that depends on irrigated feed crops. Water use in river basins is an age-old resource-management question, but it is rare to quantify consumption by specific sectors. The Colorado River is being overused for beef and dairy production, endangering the entire river ecosystem.

Wettable photothermal hollow fibers arrays for efficient solar-driven desalination under omnidirectional illumination without salt precipitation

Solar-driven evaporation based on photothermal materials is emerging as a sustainable fresh water generation technology for alleviating water scarcity. To realize the efficient and stable desalination under omnidirectional illumination, here, a “Pinscreen”-inspired photothermal hollow fibers arrays has been developed for high-efficiency and stable solar-driven evaporation under omnidirectional illumination. In the photothermal arrays design, driven by the capillary action, water was automatically taken up through the lumen side of hydrophilic alumina hollow fiber coated with polypyrrole (PPy), which also shows high light-harvesting. Thanks to the designed morphology of arrays, the evaporation amount of PPy-AHFs arrays is over 0.65 g h−1 even under parallel one-sun illumination. During a long-term desalination, photothermal hollow fibers arrays can realize controllable salt-precipitation attributed to ideal water transport. Our results of wettable photothermal hollow fibers arrays for efficient photothermal evaporation can be considered as a significant attempt to inspire the future development of novel photothermal materials in sustainable desalination.

Can we beneficially reuse produced water from oil and gas extraction in the U.S.?

There is increasing interest in beneficial uses of large volumes of wastewater co-produced with oil and gas extraction (produced water, PW) because of water scarcity, potential subsurface disposal limitations, and regional linkages to induced seismicity. Here we quantified PW volumes relative to water demand in different sectors and PW quality relative to treatment and reuse options for the major U.S. shale oil and gas plays. PW volumes from these plays totaled ~600 billion liters (BL, 160 billion gallons, Bgal) in 2017. One year of PW is equal to ~60% of one day of freshwater use in the U.S. For these plays, the total irrigation demand exceeded PW volumes by ~5× whereas municipal demand exceeded PW by ~2×. If PW is reused for hydraulic fracturing (HF) within the energy sector, there would be no excess PW in about half of the plays because HF water demand exceeds PW volumes in those plays. PW quality can be highly saline with median total dissolved solids up to 255 g/L in the Bakken play, ~7× seawater. Intensive water treatment required for PW from most unconventional plays would further reduce PW volumes by at least 2×. Desalination would also result in large volumes of salt concentrates, equivalent to ~3000 Olympic swimming pools in the Permian Delaware Basin in 2017. While water demands outside the energy sector could accommodate PW volumes, much lower PW volumes relative to water demand in most regions would not substantially alleviate water scarcity. However, large projected PW volumes relative to HF water demand over the life of the play in the Permian Delaware Basin may provide a substantial new water source for beneficial use in the future. Large knowledge gaps in PW quality, lack of appropriate regulations, and economic factors currently preclude beneficial uses outside the energy sector in most regions.

Performance of Medicago sativa Grown in Clay Soil Favored by Compost or Farmyard Manure to Mitigate Salt Stress

The use of saline water for the irrigation of forage crops to alleviate water scarcity has become necessary in semi-arid and arid regions and researchers have been seeking ways to offset the harmful results of soil salinity. Soil amendments with compost, manure and other organic material provide a valuable source of plant nutrients and appear to speed up soil recovery. The aim of this study was to compare the benefits of farmyard manure and a municipal solid waste (MSW) compost (40 mg ha−1) for raising alfalfa (Medicago sativa, cv. Gabès) under salt-water irrigation. Both compost and manure improved plant mineral uptake and growth of alfalfa cultivated in clay soil. Using compost in clay soil increased the content of copper (Cu), cadmium (Cd), and zinc (Zn) in plant tissues compared to manure, while the bio-accumulation factor (BAF) of Cu, Pb and Zn was higher in plants grown with manure compared to MSW compost with salt stress. Compost addition could enhance alfalfa growth under salt stress, which depends on salt doses and can greatly improve the recovery effects in a cost-effective way, although additional amendment type should receive special attention in order to be used as a tool for sustainable agriculture.

Alleviating Water Scarcity in the Central Rift Valley Lakes through an Inter-Basin Water Transfer, Ethiopia

Demand for fresh water, as one of the major natural resources, is increasing rapidly with increasing development and environmental degradation. The continued abstraction of water from Lake Ziway and its main feeder rivers Meki and Katar for irrigation indicates that the water demand may soon exceed the supply. To illustrate disparities in spatial distribution of water resources, the Upper Awash sub-basin, which shares a water-divide with the CRVL sub-basin, has large flow volumes particularly in the rainy season and suffers with seasonal flooding. The rationale behind regaining the water in CRVL relies on this non-uniform spatial distribution of fresh water, calling for a balance between water surplus and deficit regions. For this reason, Inter Basin Water Transfer (IBWT) is suggested as a viable option to augment utilizable water resources of the Upper Awash sub-basin to reduce the significant pressure on the water supply of the rapidly developing urban and irrigation areas in the CRVL sub-basin. A water evaluation and planning (WEAP) model was used to quantify the amount of surplus water in the donor basin, when examining the hydrological dynamics of the basins. Furthermore, optimal flow diversion scenarios were generated by maintaining two baseline scenario constraints. The estimated surplus water in the rainy season is expected to contribute 18 million cubic meters (mcm), 88 mcm and 192 mcm in months June, July and August respectively under average conditions. The optimal amount of diverted water could potentially stabilize the environmental degradation of Lake Ziway and Lake Abijata by compensating for development-driven abstraction and surface water evaporation respectively.

Forward osmosis membrane bioreactor using Bacillus and membrane distillation hybrid system for treating dairy wastewater

ABSTRACT Wastewater recycling is one of the best ways to alleviate water scarcity and water/wastewater pollution. The dairy industry is the largest industrial food wastewater source in many countries. In this study, we used a forward osmosis membrane bioreactor (FOMBR) and membrane distillation (MD) hybrid system to recycle dairy wastewater. And we developed a new Bacillus-FOMBR inoculated with salt-tolerant Bacillus sludge to protect against the negative effects of accumulated salt on sludge characteristics, microbial community and treatment effectiveness, and to alleviate membrane biofouling. A laboratory-scale FOMBR-MD experiment was operated for 40 days and water flux, salinity change, sludge characteristics, microbial community, nutrient removal efficiency, and FO membrane fouling were investigated. The Bacillus-FOMBR showed a small decrease in biomass concentration, and the hybrid system removed almost 100% of the contaminants. High-throughput sequencing analysis indicated that Pirellula and Hyphomicrobium species dominated the Bacillus-FOMBR, which are obliged to perform heterotrophic nitrification and aerobic denitrification. These nitrogen-removing bacteria ensured high nitrogen removal efficiency of the bioreactor. The total nitrogen (TN) concentration in the bioreactor increased and then decreased, which did not continuously increase as occurred in conventional FOMBRs. The TN removal efficiency of the bioreactor was mostly above 40% and the highest reached 79%. Besides, the Bacillus-FOMBR suffered little membrane biofouling because of the quorum quenching effect of the Bacillus species. We speculate that the Bacillus-FOMBR has potential to treat high-salt wastewater and high strength ammonia-nitrogen wastewater.

Hydrogels as an Emerging Material Platform for Solar Water Purification.

Growing concern over water scarcity leads to increased research interest in advanced water purification technologies. Solar water purification, which uses solar energy to separate water and impurities through vaporization, enables the utilization of sustainable energy and potential freshwater resources to alleviate water scarcity. However, the essential process of solar water evaporationto remove impurities is energy intensive. Insufficient solar absorption and thermal loss limited the vapor generation rate and, thus, lowered the purified water yield. Diffuse natural sunlight cannot satisfy the intrinsic energy demand for rapid water vaporization. Therefore, developing new material platforms that can simultaneously provide high solar absorption, effective energy utilization, and low energy demand for water vaporization to achieve highly efficient solar water purification under natural sunlight is anticipated. In this Account, we review our recent progress on hydrogel-based evaporators for solar water purification in terms of material selection, molecular engineering, and structural design. First, we introduce the unique water state in hydrogels consisting of free, intermediate, and bound water, of which intermediate water has a reduced energy demand for water evaporation. Then, we describe the design principles of hydrogel-based solar evaporators, where the polymeric networks are tailored to regulate the water state. The water state in hydrogels defines the vaporization behavior of water. Thus, the polymer networks of hydrogels can be architected to tune the water state and, hence, to further reduce the evaporation enthalpy of water. Armed with fundamental gelation chemistry, we discuss synthetic strategies of hydrogels for efficient vapor generation. By incorporating solar absorbers with hydrophilic polymer networks, solar energy is harvested and converted to heat energy, which can be in situ utilized to power the vaporization of contained water in the molecular meshes, and the solar absorbers having strong interaction with hydrogels guide the formation of microstructure to reduce the energy loss and ensure adequate water transport of evaporative water. Regulating the vaporizing fronts, engineering the surfaceof hydrogels has been focused to favor the evaporationof waterto further enhance the solar-to-vapor efficiency. By using hydrophilic polymers as building blocks, the hydrogel-based solar evaporators have also been endowed with multiple functionalities, such as antifouling, permselectivity, and thermal responsiveness, to improve water collection andpurification abilities. Taking advantages of these merits, hydrogels have emerged as apromising materials platform to enable efficient solar water purification under natural sunlight. This Account serves to promote future efforts toward practical purification systems using hydrogel-based solar evaporators to mitigate water scarcity by improving their performance, scalability, stability, and sustainability.

Cross-sectoral implications of the implementation of irrigation water use efficiency policies in Spain: A nexus footprint approach

Abstract One technical solution often suggested for alleviating water scarcity is to increase the efficiency of irrigation water use. In Spain, several plans have been launched since 2000 to upgrade irrigation infrastructures and thereby achieve water savings equivalent to 2500 hm3/year and promote rural development. The present study uses a footprint approach to evaluate the impacts on land, water, energy, and carbon emissions of the implementation of irrigation modernization policies in agriculture in Spain between 2005 and 2011. The results show that during the period studied, the irrigated area remained stable (+0.3%), although there was a shift in crop patterns, with low-value non-permanent crops being replaced by high-value permanent crops. The water demand for irrigation decreased by 21%; half of this is explained by the shift in crop patterns and the reduction of the consumptive fraction (i.e., blue water footprint), and the other half by the cutback of return flows associated with the higher efficiency of the irrigation infrastructure. Changes in water demand have been accompanied by a progressive substitution of surface water for groundwater. Reduced water demand for irrigation has brought a reduction of 13% in water’s energy footprint and 25% in its carbon footprint. In relative terms, water efficiency (m3 consumed/m3 irrigated) has increased by 8%, although this has also increased the energy intensity (kWh/m3) to 9%. The emission rate (kgCO2 equiv/m3 irrigated) has decreased by 12% as a result of the drop in the emission factor of electricity production. Overall, irrigation modernization policies in Spain have supported the transition from an irrigation sector that is less technified and heavily dependent on surface water into one that is more productive and groundwater-based. From a resource-use perspective, such transition has contributed to stabilizing or even decreasing the irrigated land, and surpass the annual water savings target of 2500 hm3, although it has also made the sector more energy-dependent. Despite the overall positive outcomes, the observed water savings are masked by various synergistic factors, including favorable climatological conditions toward the end of the study period, which contributed strongly to curbing overall irrigation water demand. In the light of the higher frequency of observed droughts in Spain, the investments done so far do not guarantee that the planned water saving targets can be sustained if not complemented with additional measures like restricting irrigated area and/or setting caps for water intensive crops.

The study on supply and demand of water resources in Alar city based on the system dynamics model

According to the status of water resources shortage in Alar, this paper establishes a system dynamics (SD) model for the water resources carrying capacity (WRCC) and analyzes the balance between water resources supply and demand. Three cases are designed to simulate the level of WRCC from 2010 to 2030. The total water demand and secondary product output value are chosen as the evaluation indices to study the WRCC in Alar. The results show that the carrying capacity of water resources in Alar cannot meet the demand of social economic development in recent years, and case 3 could effectively alleviate water scarcity. Based on the results, in order to guarantee sustainable utilization of water resources and social economy development, it is necessary to increase water saving policies and increase the introduction amount of surface water in the future.

Recommendations to derive quality standards for chemical pollutants in reclaimed water intended for reuse in agricultural irrigation

The reuse of treated municipal wastewater (herein referred to as reclaimed water) in agricultural irrigation (RWAI) as a means to alleviate water scarcity is gaining increasing policy attention, particularly in areas where water demand mitigation measures have proved insufficient. However, reclaimed water reuse in practice is lagging behind policy ambition, with <2.5% of it reused in a European context. A key barrier identified as limiting its full valorisation is concern over its impact on human and environmental health. To address this concern, and to meet further objectives including achieving parity between current reclaimed water reuse guidelines operational in various Member States, the European Commission has proposed a regulation which identifies minimum quality requirements (MQR) for a range of microbiological and physico-chemical parameters but the inclusion of compounds of emerging concern (CECs) in terms of the determination of quality standards (QS) is missing. This paper reviews the existing pertinent EU legislation in terms of identifying the need for CEC QS for RWAI, considering the scope and remit of on-going pan-European chemicals prioritisation schemes. It also evaluates opportunities to link in with the existing EQS derivation methodology under the EU WFD to address all protection targets in the environmental compartments exposed via potential pathways of RWAI. Finally, it identifies the main data gaps and research needs for terrestrial ecosystems, the removal efficiency of CECs by WWTPs and transformation products generated during the wastewater reuse cycle.

Evolution of virtual water metabolic network in developing regions: A case study of Guangdong province

Rapid urbanization has challenged the utilization and the circulation of water, especially in rapidly developing regions. It is necessary to disaggregate virtual water metabolic networks (VWMN) in representative areas, and examine their relevant dynamics to sustain regional development. In this study, the VWMN of Guangdong Province, China is developed to explore the ecological relationships between pairwise components and identify the ecological hierarchy structure of VWMN. Particularly, the structural analysis of VWMN is optimized and two indicators are proposed in this study. The integral virtual water recycling index (IVWRI) enable to reveal the extent that components are benefited from the existence of the VWEN and the integral virtual water productivity (IVWP) can identify economic output per unit integral virtual water utilization of each component. The results indicate that the tertiary industry fails to promote the development of its upstream industries, and the integral virtual water productivity of this industry is declining. Technology upgrading of manufacturing industry and steady import of primary products are imperative. Moreover, petroleum, coking, nuclear-fuel and construction industries are key components that clog the studied VWMN. This research provides scientific support for the robust development of VWMN, particularly in alleviating water scarcity and promoting sustainable regional development.

Virtual Water Flow and Water Footprint Assessment of an Arid Region: A Case Study of South Khorasan Province, Iran

Water challenges—especially in developing countries—are set to be strained by population explosion, growing technology, climate change and a shift in consumption pattern toward more water-intensive products. In these situations, water transfer in virtual form can play an important role in alleviating the pressure exerted on the limited water resources—especially in arid and semi-arid regions. This study aims to quantify the 10-year average of virtual water trade and the water footprint within South Khorasan—the third largest province in Iran—for both crops and livestock products. The virtual water content of 37 crops and five livestock is first estimated and the water footprint of each county is consequently measured using a top-down approach. The sustainability of the current agricultural productions is then assessed using the water scarcity (WS) indicator. Results of the study show that in spite of the aridity of the study area, eight out of 11 counties are net virtual water exporters. Birjand—the most populous county—is a net virtual water importer. The 10-year average water footprint of the region is measured as 2.341 Gm3 per year, which accounts for 2.28% of national water footprint. The region’s average per capita water footprint however, with 3486 m3, is 115% higher than the national ones. Crop production and livestock production are responsible for 82.16% and 17.84% of the total water footprint. The current intensive agricultural practices in such an arid region have resulted in a water scarcity of 206%—which is far beyond the sustainability criteria. This study gives the water authorities and decision-makers of the region a picture of how and where local water resources are used through the food trade network. The generated information can be applied by the regional policymakers to establish effective and applicable approaches to alleviate water scarcity, guarantee sustainable use of water supplies, and provide food security

The Clogging Rules of Ceramic Emitter in Irrigation Using Saline Water with Different EC

Infiltration irrigation with saline water is a more effective method than drip irrigation to alleviate water scarcity worldwide, but so far, no report has discussed the clogging rules of ceramic emitters, a major component of infiltration irrigation system. To explore the clogging mechanism of ceramic emitter in saline water infiltration irrigation system, we used four kinds of saline water sources with electrical conductivity (EC) of 0.18, 1.74, 3.78, and 7.74 ds/m, respectively. In addition, we specifically investigated the law of discharge ratio variation (Dra) of ceramic emitters, as well as the composition and growth process of clogging substance. The results indicated that the Dra of ceramic emitters decreased in the process of saline water irrigation, and the higher the EC, the more obvious the decrease. The calcium carbonate (CaCO3) was the main component of the clogging substance in the inner wall of ceramic emitters. The clogging part was a layer on the inner wall of the emitters rather than the pores in the walls, and the clogging did not occur suddenly. Instead, it was caused by the long–term accumulation of the clogging substance. Moreover, with the increase of EC, the flocculation between the clogging particles in the water was enhanced and thus promoted the formation of stable and compact aggregates, which fundamentally led to the clogging acceleration of ceramic emitters. This clogging mechanism of ceramic emitters can provide some theoretical reference for the establishment of anti-clogging strategy.