Virtual water accounting for building: case study for E-town, Beijing

A multi-regional input-output analysis of direct and virtual urban water flows to reduce city water footprints in Australia

Abstract. Water is an economic good that should be well accounted for globally. In most developing countries, little or no emphasis is placed on water transfer through trade of their agricultural commodities. With changing climate, there is need for developing countries to include the virtual water concept in their international trade dealings. This paper reports the virtual water flow involved in the propagation of four varieties of cassava (TMS30572, TMS980505, TMS920326, and TMS090581) obtained from IITA, Ibadan, Nigeria. Volume of water involved in cassava processing was considered. Virtual water was estimated for the period of cultivation and corresponding cassava yield. Cassava processing water use was obtained from three randomly selected cassava processing plants. At 120 Days After Planting (DAP), TMS920326 had virtual water of 7.9 m3/ton while TMS90581 had virtual water of 16.1 m3/ton. Virtual water of 13.3 m3/ton and 18.7 m3/ton were recorded for TMS980505 and TMS90581 respectively after 150 DAP. After 180 DAP, TMS980505 had virtual water of 15.5 m3/ton and TMS90581 had 20.6 m3/ton. The volume of water used in processing cassava through fermentation process was 1.5 m3/ton while that for non-fermentation process was 1 m3/ton. The results obtained suggested that virtual water flow for cassava vary with its species and processing method employed. Based on the least amount of water used in propagation, TMS980505 will give optimum returns on investment in the exportation of cassava products. Nigeria being the largest producer and exporter of cassava in the world, incorporating the amount of water used in cassava production and processing into its export value may be a step in the right direction.

A two-stage factorial-analysis-based input-output model for virtual-water quantification and metabolic-network identification in Kyrgyzstan

Virtual water embodied in international trade is equivalent to nearly one-third of global water withdrawal, confirming that trade plays a significant role in redistributing global water resources. This paper extends a virtual water analysis by measuring the extent to which virtual water embodied in traded industrial products affects the distribution of global virtual water. The distribution of global virtual water can be improved if trade in industrial products promotes virtual water outflows from water-abundant to water-scarce countries. Analyses were performed using an input–output model that can decompose water consumption into domestic demand and exports by destinations of trade. Focusing on Malaysia, the results indicate that trade in industrial products between Malaysia and its main trading partners have a limited capacity to improve the distribution of global virtual water. This limitation can be due to two reasons. Firstly, exports of Malaysian industrial products are mainly driven by less water-intensive sectors. Therefore, the amount of virtual water that outflows into other countries is also low. Secondly, trade in Malaysian industrial products largely involves water flows with other water-abundant countries. Only several water-scarce countries benefit from virtual water trade in industrial products with Malaysia, namely the Netherlands, Australia and China.

Provincial virtual energy-water use and its flows within China: A multiregional input-output approach

This paper introduces the virtual water and the virtual water trade. Based on the input-output theory, we analysis the water consumption features and virtual water trade of the national economy and industry of Tianjin. We analysis the water feature by the direct water input coefficient, the total water input coefficient and the water coefficient of added value, and analysis the virtual water trade of Tianjin in 2002, 2005and 2007 in perspective of production and consumption. The results showed that: The electrical machinery and equipment manufacturing industry, the transportation equipment manufacturing and the electronic equipment industry is a net output of virtual water trade, three water consumption coefficients of the three industry are relatively small, so the net output of them is attribute to the large export of them. The virtual water of the agricultural, the chemical and the textile and garment industry is net output in 2002 and net input in 2007, of which the agriculture has a relatively high direct water input coefficient, the chemical and the textile and garment industry have high indirect water input coefficients. The net input industry contains the food manufacturing and tobacco processing industry, the metallurgy industry and so on. Tianjin changed the state of virtual water trade and became a net transferred region from 2002 to 2007. It shows that the adjustment of industrial structure of Tianjin is toward to the direction of water-saving. At the same time, we should focus on the reduction of the virtual water of agriculture, the conservation of industry and should focus on the development of the tertiary industry (service) in the future.

The populations of most nations consume products of both domestic and foreign origin, importing together with the products the water which is expended abroad for their production (termed ‘virtual water’). Therefore, any investigation of the sustainability of present-day water consumption under future climate change needs to consider the effects of potentially reduced water availability both on domestic water resources and on the trades of virtual water. Here we use combinations of Global Climate and Global Impact Models from the ISI–MIP ensemble to derive patterns of future water availability under the RCP2.6 and RCP8.5 greenhouse gas (GHG) concentrations scenarios. We assess the effects of reduced water availability in these scenarios on national water consumptions and virtual water trades through a simple accounting scheme based on the water footprint concept. We thereby identify countries where the water footprint within the country area is reduced due to a reduced within-area water availability, most prominently in the Mediterranean and some African countries. National water consumption in countries such as Russia, which are non-water scarce by themselves, can be affected through reduced imports from water scarce countries. We find overall stronger effects of the higher GHG concentrations scenario, although the model range of climate projections for single GHG concentrations scenarios is in itself larger than the differences induced by the GHG concentrations scenarios. Our results highlight that, for both investigated GHG concentration scenarios, the current water consumption and virtual water trades cannot be sustained into the future due to the projected patterns of reduced water availability.

Input–output analysis of virtual water transfers: Case study of California and Illinois

Background and Objectives: One of the practical strategies for managing water resources is to estimate the plant's water needs and determine the amount of water used in the various stages of crop production. In order to calculate the amount of water consumed by agricultural products in the growth stages, the virtual water index and water footprint are used. Water footprint in a product is defined as the volume of fresh water used in it's production. Water footprint is defined as an indicator for the allocation of fresh water resources that provides valuable insights into the environmental impact of producing a product. Water footprint index shows actual consumption of water in three components: blue, green and gray, which is now considered in the direction of modern management of water resources with an integrated approach. In order to properly assess water consumption in the agricultural sector, it is necessary to study the water footprint index in different climates. Materials and Methods: To conduct the research, meteorological data were first obtained from the Meteorological Organization.Then the water needs of sugar beet, potato, forage corn and tomato plants in Hamedan, Ahvaz, Shahrekord, Mashhad and Isfahan climates were calculated from the CropWat software. The yield of the crop and the amount of nitrogen fertilizer used were obtained from the agricultural jihad of each province. crop yield and the parameters required in the calculations were calculated and aggregated through agricultural statistics Then, the average volume of water consumption, virtual water, water footprint and water use efficiency of these products were calculated for the statistical period of 2011-2017. Chapagin et al. (2006) Method was used to calculate water footprint. Results: In the present study, water consumption for agricultural products was investigated. The results showed that among the studied products, the potato plant with 2945.4 m3/ton in Ahvaz city with hot and humid climate has the highest water footprint and sugar beet with 906.1 m3/ton in climate cold and dry of Mashhad has the least water footprint. The highest amount of virtual water used for the studied plants is potato (0.84 m3/kg), tomato (0.51 m3/kg), sugar beet (0.46 m3/kg) and forage corn (0.39 m3/kg) was respectively to the climate of Ahwaz, Shahrekord, Ahwaz and Isfahan. The lowest amount of water consumption efficiency (1.2 kg/m3) also belonged to the potato in Ahvaz climate. The lowest virtual water and the highest water consumption efficiency for the studied plants were obtained in Hamedan climate. Conclusion: In the present study, water consumption for agricultural products was investigated. The results showed that the volume of water consumed in the studied products varies in different climates. According to the obtained results, it can be said that the climate of Hamedan due to the low amount of virtual water (0.29, 0.3, 0.19 and 0.14 m3/ kg) and high water consumption efficiency ( 3.43, 3.3, 5.19 and 7.46 kg/m3) for potatoes, tomatoes, sugar beets and fodder corn, respectively, compared to other climates studied for cultivation of all four the product is more suitable. Hence, according to recent droughs and water shortage, available water resources should be used accurately and decision must be made for cultivating the products with less water requirement and better performance.

Virtual water transfers in Africa: Assessing topical condition of water scarcity, water savings, and policy implications

Agriculture has a long-standing tradition over the Italian territory, and its geography is significantly heterogeneous across regions, due to different hydro-climatic conditions and local practices. This chapter examines the Italian water use in the agricultural sector by considering both the local water use and the reliance on external water resources occurring through the import of primary and derived commodities. The water assessment is carried out by means of the “water footprint” concept, which aims at quantifying the amount of water required for the production of a good, and the “virtual water trade”, which tracks the exchange of water resources from producing countries, where water has been physically used, to consuming countries. In the first part of this chapter, the Italian virtual water balance is analysed considering the amount of water imported, exported and locally used for production. Overall, an increase of the virtual water import and a decline in the use of local water resources are observed: Italy relies on imported water resources for more about half of its food consumption. In the second part, the role of Italy in the international trade network is assessed. Results show that Italy is primarily a net importer of virtual water from other countries (e.g. France, Germany, Brazil, Indonesia), but, at the same time, it is also a net exporter towards the UK, the Mediterranean region, the USA and other minor countries. In the third part, the spatial variability of water use across Italy is explored, looking at the subregional spatial variability to highlight the production sites generating the largest water footprint.

The purpose of this paper is to analyze the change trend of the virtual water trade for a 15-year period in Shandong Province, and to discuss how ecological environment is affected by numerous virtual water trade in a representative region. To carry out the analysis, the authors derived a water balance model from lateral economic balance formula in the input-output table. The model was combined with the economic data from Shandong Province’s input-output tables and environmental Kuznets curve for an analysis of the change trend of virtual water trade of different industries. Findings - The agriculture is the largest industry that consumes water among three industries, and it plays a conclusive role on whether Shandong Province export virtual water or import virtual water. The virtual water of the province was exported in 1997 and 2002 and imported in 2007 and 2012. This situation was in line with the change of the environmental Kuznets curve and such transformation can be considered a kind of repair to the ecological environment. When the net output volume of virtual water was zero, the total output value of agriculture was 257.86× 109 Yuan. About the representative region (Shouguang City), the annual irrigation water of vegetables is approximately 1.6× 108 m3, of which 84.5% water is exported to other areas in the form of vegetable trade. The virtual water quantity exported in the form of vegetable accounted for approximately 73% of the annual average groundwater resources. Shandong Province has insufficient water resources, and this study can provide a scientific basis for allocating water resources and repairing ecological environment.

Unpacking the urban virtual water of the Global South: Lessons from 181 cities

Virtual Water Flows in North America

<p>Water scarcity is a significant risk for meeting increasing food demand around the world. The importance of identifying the driving forces behind water consumption in agriculture and relative virtual water (VW) flows has been widely reported in order to provide practical advice for sustainable agricultural water resource management. However, the regional differences in the driving forces behind either water consumption or VW flows were largely ignored. To fill the crucial gap, taking nine major crops grown in the Beijing-Tianjin-Hebei (BTH) region in China over 2000-2013 as the study case, we investigate the regional differences in socio-economic driving forces on both the estimated water footprint (WF) in crop production and relative inter-city VW flows for each crop per year. Results show that although there is little change in total WFs in crop production (~43.3 billion m<sup>3</sup>/y on annual average), the WF per unit mass of crop decreased and the crop structure in the total WFs changed greatly. The BTH region was a VW importer with net VW import of 11.7 billion m<sup>3</sup>/y by 2013. The per capita GDP was the main positive driver of both total WFs of crop production and relative VW flows. Whereas the economic productivity and consumption ability were inhibiting factors for the WFs and VW flows, respectively. The levels of total crop WFs in agricultural cities were more sensitive to the effects of the main driving factors. The intensity of driving factors behind the inter-regional crop-related VW flows was shown to be directly related to the regional role as an importer or exporter. The current analysis suggests to develop characteristic agriculture considering the local role and regional differences in terms of water consumption and relative inter-regional VW flows, aiming for a balance between water sustainability, food security and economic developments.</p>