Spatial Heterogeneity of Embedded Water Consumption from the Perspective of Virtual Water Surplus and Deficit in the Yellow River Basin,China

Virtual water trade(VWT)provides a new perspective for alleviating water crisis and has thus attracted widespread attention.However,the heterogeneity of virtual water trade inside and outside the river basin and its influencing factors remains further study.In this study,for better investigating the pattern and heterogeneity of virtual water trade inside and outside provincial regions along the Yellow River Basin in 2015 using the input-output model(MRIO),we proposed two new concepts,i.e.,virtual water surplus and virtual water deficit,and then used the Logarithmic Mean Divisia Index(LMDI)model to identify the inherent mechanism of the imbalance of virtual water trade between provincial regions along the Yellow River Basin and the other four regions in China.The results show that:1)in provincial regions along the Yellow River Basin,the less developed the economy was,the larger the contribution of the agricultural sector in virtual water trade,while the smaller the contribution of the industrial sector.2)Due to the large output of agricultural products,the upstream and midstream provincial regions of the Yellow River Basin had a virtual water surplus,with a net outflow of virtual water of 2.7×10^(8) m^(3) and 0.9×10^(8) m^(3),respectively.3)provincial regions along the Yellow River Basin were in a virtual water deficit with the rest of China,and the decisive factor was the active degree of trade with the outside.This study would be beneficial to illuminate the trade-related water use issues in provincial regions along the Yellow River Basin,which has farreaching practical signific-ance for alleviating water scarcity.

Areal differentiation of virtual water for agricultural products and its effect on regional agricultural structure adjustment in China: 1995-2007

With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security.

Sustainability and virtual water:The lessons of history

This article aims to show that virtual water has historically been an adaptation strategy that enabled some arid regions to develop a prosperous economy without putting pressure on their scarce water resources.Virtual water is referred to as the total amount of water that is consumed to produce goods and services.As an example,in arid central Iran,the deficiency in agricultural revenues was offset by more investment in local industries that enjoyed a perennial capacity to employ more workers.The revenues of local industries weaned the population from irrigated agriculture,since most of their raw materials and also food stuff were imported from other regions,bringing a remarkable amount of virtual water.This virtual water not only sustained the region’s inhabitants,but also set the stage for a powerful polity in the face of a rapid population growth between the 13th and 15th centuries AD.The resultant surplus products entailed a vast and safe network of roads,provided by both entrepreneurs and government.Therefore,it became possible to import more feedstock such as cocoons from water-abundant regions and then export silk textiles with considerable value-added.This article concludes that a similar model of virtual water can remedy the ongoing water crisis in central Iran,where groundwater reserves are overexploited,and many rural and urban centers are teetering on the edge of socio-ecological collapse.History holds an urgent lesson on sustainability for our today’s policy that stubbornly peruses agriculture and other high-water-demand sectors in an arid region whose development has always been dependent on virtual water.

Evaluation on Water Resources and Determining the Values of Exported and Imported Virtual Water in Hashtgerd Region

The concept of virtual water in recent years has been proposed with the world’s water resource consumption management approach. Hashtgerd study area is one of 609 study areas of the country that is located entirely in Alborz Province. Average annual rainfall in this region was about 200 to 340 mm and the average agricultural production per year was more than one million tons and had more than 16 million cubic meters surplus recovery from underground water resources. The aim of this study is to evaluate resources and amounts of virtual water in the agricultural sector of the study area and its impact on the area water resources balance and ultimately provide solutions to reduce water consumption by the agricultural sector. The most important exported water products in Hashtgerd area in order of importance are peaches and nectarines (33% of water exports), plums (15% of water exports), vegetables (5.14 percent of water exports), cherry (4.7% of water exports) and wheat (6.5 percent of water exports). Virtual water trade balance of agricultural and horticultural products in the digital range is equal to 260+ million cubic meters. Density of agricultural lands can be mentioned as the main reasons for positive balance of virtual water trade in this area.

The Strategic Importance of Cereal Virtual Water in Algeria： Report and Perspectives

In order to quantify the virtual water part which is contained in the imported cereals, compared with the hydraulic potentialities which are annually mobilised through the national territory, and on the basis of the agricultural statistics, we have determined the average quantities of the imported cereals per year in order to determine the virtual water volume that these cereals bind. The water needs of the cereals which are produced in Algeria have been calculated by the Cropwat software, in order to define the equivalent quantities of water in their production on the national scale. The obtained results confirm the importance of the annually imported virtual water, through the imported cereals, comparing with the national hydraulic potentialities. Our study shows also that in spite of the strategic importance of the virtual water in the imported cereals, a diminution has to take place, on the average term, by an improvement of the use efficiency of the precipitations （green virtual water） using the best mastery of the technical itinerary in general, and also the efficient use of precipitations in particular.

Analysis of China’s Water Security and Virtual Water Trade

Producing goods and services all needs water consumption.The water used in the process of an agricultural or industrial product is called the"Virtual Water"contained in this product. Through international trade,water-scarce countries and regions could purchase water-intensive products--especially foods,from water-rich countries to balance their water deficits and achieve water safety.China is one of the 13 most water-deficit countries whose water safety have been severely challenged.This paper generalized the recent global research development and made a brief introduction about the methods calculating virtual water content in specific products.As a case study,we qualified China's annual virtual water flows from year 2000 to 2002 with trade in crops,and ended with some policy advice for application and practice of virtual water strategy.

Regional Virtual Water Trade Strategy in Drought Area in China

[Objective]The aim was to analyze the virtual water trade in drought area in China.[Method]Taking agricultural production which was related to water resources as study object and by dint of opportunity cost and comparative advantage theory,water resources have been included into a series of state macro-objective models,such as economic growth,crops safety,and increase of people’s well-fare.Virtual water resource strategy was verified effectively and relevant suggestions on virtual water trade in the drought areas in China were proposed.[Result]Virtual water strategy can be implemented in places where water resource was limited so as to get low-water-demand products and change products with humid areas.But the premise was that the production technology of watery product in humid area was higher than the limited-water area,so that there can be adequate impetus to involve into virtual water strategy program and enhance each other’s benefits through commerce and ease water resources shortage and ecological destruction problem and stimulated economic development.[Conclusion] The study provided scientific basis to solve the water shortage problem in China.

Analysis of water resource benefits due to power grid interconnections using the virtual water method

The global water demand and supply situation is becoming increasingly severe due to water shortage and uneven distribution of water resources.The highest water demand in the energy sector is attributable to power generation.With cross-country and cross-continental power grid interconnections becoming a reality,electricity trading across countries and the creation of new opportunities for re-allocation of water resources are possible.This study expands the concept of virtual water and proposes a generalized virtual water flow in an interconnected power grid system to accurately estimate water resource benefits of clean power transmission from both the production and the consumption sides.By defining the water scarcity index as a price mechanism indicator,the benefits of water resources allocation through power grid interconnections are evaluated.Taking the Africa-Asia-Europe interconnection scenario as an example,the total water saving would amount to 88.95 million m^3 by 2030 and 337.8 million m^3 by 2050.This result shows that grid interconnections could promote the development of renewable energy and expand the benefits of available water resources.

Virtual Water on the Southern High Plains of Texas: The Case of a Nonrenewable Blue Water Resource

This paper utilizes the virtual water concept to evaluate water usage of agricultural production in West Texas. This work evaluates the measure of virtual water, as it relates to informing water policy in a semi-arid, agriculture-intensive region, which relies upon a minimally renewable groundwater resource. The results suggest that production in the region reflects a collective effort to capture the highest value from the water resource, consistent with the virtual water philosophy, even in the absence of specific water policy toward that goal. Additionally, this work takes advantage of high resolution data to reinforce the need to calibrate virtual water calculations to account for regional differences.

Agricultural Water Foot Print and Virtual Water Budget in Iran Related to the Consumption of Crop Products by Conserving Irrigation Efficiency

In this study we estimate agricultural water footprint and its components from consumption perspective in arid and semi-arid region like Iran. This study is based on blue water consumption in irrigated land. Iran has imported net virtual water about 11.64 billion cubic meters (bcm) as international crop trade in 2005-2006. Therefore, Iran has depended on virtual water imports. By conserving about 60% irrigation efficiency, the total water requirement to produce imported crops in Iran is nearly 20.78 billion cubic meters. It is nearly 9 percent of renewable water resources and 12.65% agricultural appropriated water which has added to internal water resources. Agricultural virtual water budget is about 112.78 Gm3/yr. Agricultural water footprint is 110.2 Gm3/yr. About 12.83% of agricultural water footprint of Iran is related to external water resources on the country boundaries. It means external water footprint. Water dependency, water self-sufficiency and water scarcity indexes in agricultural sector of Iran, are estimated 10.1%, 89.9% and 70.8%, respectively.

Efficiency,Equity and Effect:a case study on virtual water consumption characteristics

Scarcity of water is the key factor restricting the growth of social economy.The virtual water theory provides a new way to solve the problem of water scarcity.For this paper,we have calculated the virtual water consumption of each household,grouped by income,of Gansu province for 1992-2005.Then we advanced the indicator of virtual water with per-unit-of-consumption expenditure to analyze the efficiency of virtual water consumption.Additionally,we recurred to the diversity theory advanced by Ulanowicz,which is broadly employed by ecologists and biologists,to analyze the characteristics of virtual water consumption.As a result,the virtual water consumption of each group decreased yearly from 1992 to 2005,on the whole;decreasing proceeded slower during the period of 1992-1997 than during 1998-2005.Per-unit-consumption expenditure of virtual water for each group represents the same characteristics,on the whole,as virtual water consumption.The largest variation of this indicator exists in the group of the lowest income,which ranges from 1.58 to 0.18 m3/Yuan.yr;whereas the least exists in the highest income group,which is 0.58 to 0.07 m3/Yuan.yr.The virtual diversity indicator increased year by year,and the change of this indicator in 1992-1997 was more obvious than in 1998-2005.Finally,from this study we find that,in view of virtual water,we can save water by means of changing consumption patterns and increasing consumption diversity,but without degrading the quality of living and reducing the demands of living.When the problem of water scarcity becomes more and more serious in Gansu of China,this suggestion becomes more and more important.The consumption,the role of guiding production produce,is very important.An unsustainable consumption pattern is the main factor causing the deterioration of the world environment,especially in a developing country.The sustainable consumption is the only way to develop human beings and achieve the economical sustainable economics.

Virtual Water Trade and Food Security for Iraq

Iraq depends on its water resources from the water of the Tigris and Euphrates Rivers and their tributaries. Now, the flow of these rivers is decreasing, and Iraq is experiencing a water shortage problem. The situation is expected to be graver in the future if no action is considered. It is expected that the population will be about 70 million in 2050 and about 90 million in 2070. In such a case, thus, the quantities of water available in the future will not be sufficient to produce most of the requirements of food security, whether that be from agricultural or animal products. To overcome this problem, water management planning should be based on scientific background to overcome the present and expected problems. One of the main factors to be considered should be based on scientific studies of the virtual water footprint of different food crops to provide the largest possible amount of virtual water and avoid the acute shortage of its national water from surface and ground irrigation water (blue water) and rainwater (green water), in addition to working hard to provide the largest possible amount of desalinated water and refined sewage (gray water). In addition, any strategic plan for sustainable development in the country must be comprehensive so that it is not satisfied with improving the situation in the field of food security related to water security, but rather among its other elements is community development that directly affects food security, including setting policies to reduce consumption by reducing the steady increase in population where the population rate is 2.97% now. Collective awareness and guidance programs in all the fields of water and food security are very important to be adopted, so that everyone knows that the issue of food security and what derives from it are an existential issue related to the survival of Iraq as a state and people. In this research, facts are stated so that action is to be considered to minimize the water shortage problem. The new strategic water resources management plan is to be adopted that considers existing and future expected problems.

Virtual Water Trade as a Strategy to Water Resource Management in Iran

Agriculture has historically played a central role in the economy, life and culture of the Iranian population. Nowadays, this sector is facing the reality that its natural fresh water resources become fully utilized. Considering the climate conditions and limitation of using new water resources and the necessity of increasing agricultural product as a result of population growth, there is a general doubt about Iran’s ability to maintain this level of production amid the mounting water challenges, among other obstacles. Therefore, the evaluation of virtual water and water footprint can provide new indicators for informing water policy decisions. So, in order to study the situation at the national level, we estimated virtual water consumption in term of virtual water theory as well water footprint in agriculture sector of Iran. Data from 2001-2008 were used to account for yearly. The results of this study show that Iran has water import dependency and also net water import is 12.7 billion m3 averages. So Iran country saved 12.7 billion m3 from their domestic water resource for utilization in other sectors. Finally, it should be concluded that virtual water trade as a policy measure to water resources management will be provided to a great extent in order to reach both significant water saving and environmental sustainability.

Virtual water: an effective mechanism for integrated water resources management

In regions, which suffer from water shortage or potential water shortage like the Middle East, water policies and different mitigation measures are formulated. With the increasing population and increasing demand for food and drinking water with the fixed supply of water, the demand management policies have been introduced. Virtual Water has been adopted as an alternative or potential alternative water resource. In the application of the Integrated Water Resources Management (IWRM), virtual water has to be considered as a resource of water. In this paper, the practical value of the virtual water concept as well as the possibility of the application of the concept in the regional and national level are discussed. The paper emphasizes on the application of virtual water in agriculture products and virtual water trade of these products. This research concluded that, there is a possibility for the application of the virtual water concept on the national level taking into account water endowments, and other natural and social economic conditions. The virtual water strategy seeks ways to consciously and efficiently utilize the internal and external water resources to alleviate water scarcity. This, however, by no means implies that importing food is the only response the water scarce countries and regions should and can take. Other measures concerning the supply and demand sides of water management are imperative. The argument here is that the virtual water strategy should be an integral component in the whole package of integrated water resources management.

Analysis of Water Resources Carrying Capacity of the “Belt and Road” Initiative Countries based on Virtual Water Theory

Most countries along the route of the"Belt and Road"initiative are faced with a shortage of water resources.However,successful implementation of the initiative depends on water availability to support economic and social development.We designed a water resources carrying capacity evaluation index system,assigned grades and weights to each evaluation index and calculated a water resources carrying index for the 65 countries along the route.We used virtual water theory to analyze China's net virtual water import from key bulk agricultural products through international trade.For more than half of the countries along the route,their water resources will be unable to support the economic development that will be necessary for fulfilling the goals of the Initiative.As a country with insufficient water resources carrying capacity,China is a net virtual water importer in the virtual water trade.This virtual water trade can improve China's water resources support capacity,and ensure China's water and food security for the future.

Changes in agricultural virtual water in Central Asia,1992-2016

In recent years,flows of many rivers and lakes have become reduced in arid and semi-arid regions around the world.The most typical examples of this phenomenon occur in Central Asia,and the reduction of the Aral Sea area is closely related to agricultural water use.However,due to a lack of continuous data in Central Asia spanning many years,"virtual water"is used to evaluate changes in agricultural water use.Based on virtual water theory,325 kinds of agricultural products in eight categories are selected as the research object,and changes in virtual water are calculated for Central Asia from 1992 to 2016.Results indicate that:(1)The average annual net export of agricultural virtual water(TVWNE)in Central Asia is about 9 billion m3,concentrated in Kazakhstan,whose annual TVWNE reaches 8.1 billion m3.(2)Since 2007,the TVWNE in Central Asia has dropped significantly,with a drop rate of 86%,while the total volume of agricultural virtual water has gradually increased since 1998.(3)The upstream and downstream countries in Central Asia have different characteristics in the change of virtual water quantity.

An Integrated Framework for Regional Assessment of Water, Energy, and Nutrients from Food Loss of Selected Crops in the Lower Fraser Valley, Canada

Although there is no global shortage of food or water, food security has not been achieved, as human activity has turned these vital resources into “waste”. Wasted food not only loses valuable water resources but embedded calories of human energy and nutrients for healthy human populations. The Food and Agricultural Organization of the United Nations, in addressing these concerns, focuses on a global scale largely on an economic estimate of individual components of energy or water or nutrient loss. It is suggested that more information is required through local or regional assessments to provide better estimates, incorporating regional factors of the losses along the food supply chain. To address this suggestion, this study focused on an intensive agricultural and rapidly urbanizing region of Canada, the Lower Fraser Valley of British Columbia. Seven selected crops, including annual crops such as green peas, sweet corn and potato, and perennial crops that included three berry crops were assessed for their water, both constituent and virtual, as well as embedded energy, protein, and Vitamin C. Annual virtual water losses were higher for sprinkler than drip irrigation, ranging from 82 × 106 kg of water for strawberry to 7570 × 106 kg for blueberry. These high virtual water losses estimated along the food chain confirm the significance of food loss impacts on local water resources. Estimates of losses of food in kg were highest at the consumer level along the food chain and it was estimated that wasted food from the seven crops selected would have supplied the protein and caloric energy of over 33,000 men per year and Vitamin C of about 240,000 men per year. This assessment increases the awareness of food loss impacts from a regional perspective and provides a framework for future research on both environmental and nutritional implications of wasted food.

Water, Energy and Nutrient Losses from Food Wastage of Selected Crops in Three Agro-Climatic Zones in British Columbia, Canada

Food waste is a growing global concern. Data on the factors and magnitude are largely global estimates, thus local studies aid in providing information on the impacts of food waste. Three important agro-climatic zones in British Columbia and nine common crops, both annual and perennial, were selected to evaluate the environmental and nutritional implications of local food waste. Using Canadian estimates of total food waste, the constituent water, caloric content, protein, vitamin C, phosphorus and potassium wasted by each crop were estimated. Regionally, the total production and losses were the highest in the Lower Fraser Valley which had high production of potatoes and blueberries, followed by the Okanagan, with grapes and apples, and Vancouver Island, with potatoes. Virtual water was estimated by the BC Agriculture Water Calculator and used to assess the soil and climatic factors impacting the local water demand. Although soil texture seemed to influence water demand, the agro-climatic zone was the main factor controlling the water demand and the corresponding amount of water wasted. Dry agro-climatic zones had annual virtual water up to two times higher for the same crop and soil texture. Lower water demand crops, finer soils and more efficient irrigation systems were more congruent with water stress scenarios. Total losses for each region were based on conservative estimates and would have supplied the caloric energy and protein for over 40,000 adults, and vitamin C for over 300,000 adults for one year. Additionally, the total N, P and K wasted accounted for up to 32, 2 and 13 kg/ha respectively for common fertilizers used in British Columbia. This study confirmed the significance of food waste impacts on local water demand, human nutrition and soil management based on regional data for representative crops.

Water Footprint in a Basket of Exportable Agricultural Products of San Juan Province

This paper calculates the water footprint(WF)and virtual water(VW)for a basket of exportable agricultural products of San Juan province.This basket includes:onion,white garlic and grapes for raisins.The VW of these three productions is calculated and the consumption is evaluated in relation to the theoretical water reservoir capacity of the province.It is compared with results of other jobs.The methodology used is based on the WF assessment manual and on Food and Agriculture Organization’s(FAO’s)CROPWAT 8.0 model to identify the crops’water requirements and on the CIMWAT 2.0 climate database.Finally,recommendations are made for a more efficient use of water for agricultural production.

Analysis on Buckling Performance of Submarine Pipelines During Deepwater Pipe-Laying Operation

Pipes inevitably encounter high ambient pressure and bending moment during the deepwater pipe-laying process,which can lead to elliptical buckling and even deterioration failure.For the safety of pipe-laying operation,available formulas for the pipe stability are established on the basis of the assumption of uniform deformation along the tube length and symmetrical buckling.This method can predict the nonlinear response of elliptical collapse of steel circular tubes for different ratios of diameter to thickness（D/t）under pure bending or combined bending and external pressure.In these formulas,the strain-displacement relationship is deduced from the nonlinear ring theory,and the Ramberg-Osgood constitutive model is applied to simulate the inelastic material behavior.Meanwhile,the principle of virtual work is adopted to derive the equilibrium equations.A set of equations is solved by the Newton-Raphson method,and the iterative scheme contains nested iteration for the constitutive relation.In order to check the effectiveness of this theoretical method,illustrative examples are presented in this paper.Besides,the numerical simulation is carried out by use of ANSYS.A comparison of the results shows that the theoretical method can provide reasonable prediction for engineering practice.