Water Footprints and Sustainable Water Allocation

Boosting species evenness, productivity and weed control in a mixed meadow by promoting arbuscular mycorrhizas

Lowland meadows represent aboveground and belowground biodiversity reservoirs in intensive agricultural areas, improving water retention and filtration, ensuring forage production, contrasting erosion and contributing to soil fertility and carbon sequestration. Besides such major ecosystem services, the presence of functionally different plant species improves forage quality, nutritional value and productivity, also limiting the establishment of weeds and alien species. Here, we tested the effectiveness of a commercial seed mixture in restoring a lowland mixed meadow in the presence or absence of inoculation with arbuscular mycorrhizal (AM) fungi and biostimulation of symbiosis development with the addition of short chain chito-oligosaccharides (CO). Plant community composition, phenology and productivity were regularly monitored alongside AM colonization in control, inoculated and CO-treated inoculated plots. Our analyses revealed that the CO treatment accelerated symbiosis development significantly increasing root colonization by AM fungi. Moreover, the combination of AM fungal inoculation and CO treatment improved plant species evenness and productivity with more balanced composition in forage species. Altogether, our study presented a successful and scalable strategy for the reintroduction of mixed meadows as valuable sources of forage biomass; demonstrated the positive impact of CO treatment on AM development in an agronomic context, extending previous observations developed under controlled laboratory conditions and leading the way to the application in sustainable agricultural practices.

Spatio-Temporal Characteristics of Water Ecological Footprint and Countermeasures for Water Sustainability in Japan

Water-related problems are mostly caused by water imbalances between supply and demand. This study adopts the ecological footprint method to conduct an empirical study on the sustainable utilization of water resources in Japan. According to the basic principles and calculation methods of water ecological footprint (WEF), the characteristics of Japan's water ecological footprint were investigated from the time and space dimensions, and a comparative analysis was made with the water ecological footprint of China. The results show that: from 1980 to 2020, the total water ecological footprint in Japan showed a downward trend in both the traditional account and pollutant account, and its spatial pattern was characterized by the relation that the higher the urbanization rate, the larger the water ecological footprint. In terms of water ecological footprint efficiency, Japan's agricultural water ecological footprint efficiency was the lowest, and the domestic water ecological footprint efficiency was the highest. The water resources policies and measures that Japan and other developing countries should take to ensure the sustainability of water resources were analyzed separately.

Water footprint comparison of a naphtha-fired combined cycle power plant and a coal-fired steam power plant

The vulnerability of the power generation industries vulnerability to the availability of water is widespread and growing. In this regard, water footprint (WF) is one method to assess this challenge. The present study conducts the WF of a naphtha-fired combined cycle power plant (CCPP) and a coal-fired steam power plant (CSPP). For carrying out WF, it is prudent to look after water consumption during operations and the supply chain stages. Hence, in this regard, two methods have been adopted to investigate the WF of both power plants. The first method deals with the water balance mass diagram (direct WF), and the second method deals with the water supply chain (indirect WF). Evaporation loss appears to be a significant contributing factor to the direct WF. On the other hand, operational WF seems to be an essential contributing factor to indirect WF. Furthermore, the result also shows that specific water consumption in CSPP is 3.54 m³/h, whereas, in CCPP, it is 0.9 m³/h. Finally, some methods have also been suggested to reduce WF in both power plants.

Determinants of Food Consumption Water Footprint in the MENA Region: The Case of Tunisia

Tunisia, like most countries in the Middle East and North Africa (MENA) region, has limited renewable water resources and is classified as a water stress country. The effects of climate change are exacerbating the situation. The agricultural sector is the main consumer (80%) of blue water reserves. In this study, to better understand the factors that influence the food water footprint of Tunisian consumers, we used a multiple linear regression model (MLR) to analyze data from 4853 households. The innovation in this paper consists of integrating effects of socio-economic, demographic, and geographic trends on the food consumption water footprint into the assessment of water and food security. The model results showed that regional variations in food choices meant large differences in water footprints, as hypothesized. Residents of big cities are more likely to have a large water footprint. Significant variability in water footprints, due to different food consumption patterns and socio-demographic characteristics, was also noted. Food waste is also one of the determining factors of households with a high water footprint. This study provides a new perspective on the water footprint of food consumption using “household” level data. These dietary water footprint estimates can be used to assess potential water demand scenarios as food consumption patterns change. Analysis at the geographic and socio-demographic levels helps to inform policy makers by identifying realistic dietary changes.

Ecological network analysis of an urban water metabolic system: Integrated metabolic processes of physical and virtual water

The contradiction between social economy and water environment has become increasingly prominent, and the analysis of urban water metabolism system (UWMS) represents a problem-solving approach from the perspective of the entire flow process. However, a comprehensive UWMS model that considers both physical and virtual water flows is currently lacking. This paper presents an innovative application of an ecological network model of the UWMS-integrated metabolic process of physical and virtual water in Xining during the 2002-2018 period. By analysing and screening the metabolic characteristics, metabolic structure and metabolic relationships, the sustainability of the UWMS is evaluated in depth, and the main causes and critical compartments of the unhealthy metabolic process are identified. The findings show that the UWMS in Xining maintains a moderate level of robustness (the average R = 0.48) with limited metabolic efficiency. Since 2012, the water management policies in Xining have been significantly strengthened, contributing to a slight increase in robustness by improving the water use efficiency and metabolic structure. The integrated metabolic process is unhealthy because the metabolic structure is not reasonable, and the systematic metabolic relationship tends to be antagonistic due to the network mutualism index dropping to 1.0 during 2016-2018. We conclude that efficient irrigation management, more infrastructure projects for the sewer network, wastewater treatment and recycling could provide effective support to enhance the coordinate development of the social economy and water environment in Xining.

A Study on the Relationship between Income Change and the Water Footprint of Food Consumption in Urban China

We use a threshold model to analyze the relationship between per capita income and the per capita water footprint of food consumption in the urban Guangdong Province of China, and further simulate the effect of changes in income distribution on the per capita water footprint of food consumption. The income growth of urban residents has a significant positive effect on the per capita water footprint of food consumption, where the effect varies by income stratum. The income elasticity of the per capita water footprint of food consumption for the total sample is 0.45, where the income elasticity of the low-income group (0.75) is greater than that of the high-income group (0.23), indicating that a change of income in the low-income group has a greater effect on water resources. The simulation results show that increasing the income of residents, especially that of the low-income group, significantly increases the water footprint due to food consumption for the whole society. At present, China is in a period of rapid economic growth and urbanization, comprising a period of profound change and sensitive response to the income level of urban and rural residents. Therefore, in order to reduce the effect of food consumption on the environment, sustainable food consumption management strategies should consider group differences. We should correctly guide all kinds of groups to carry out sustainable consumption, advocate healthy and reasonable diet models, reduce animal food consumption, avoid the excessive consumption of food, and strengthen the management of food waste.

Accounting for Water Footprint of an Open-Pit Copper Mine

Water is a crucial input for any production system, and mining is no exception. A huge amount of water is being used in the various phases of mining activities. In the coming decades, the competition in using a sufficient amount of fresh water will become a major hurdle for the mining industry. Water footprint (WF), an accounting framework for tracking the amount of water used to produce a unit of product, can be useful to the mining companies by quantifying their water resource appropriation and identifying ways to reduce the consumption. In this study, we accounted for the green, blue, and grey water footprint of an open-pit copper mine that is located in Laos. The input–output water flows of the mine are also developed from the inventory of water use. Moreover, we have calculated the uncertainty in the water footprint accounting to check the robustness of the findings. According to the results, the green, blue, and grey WF of the studied mine are 52.04, 988.83, and 69.78 m3/tonne of copper concentrate, respectively. After the installation of a passive effluent treatment system in 2013, the calculated grey WF of the mine was 13.64 m3/tonne, a fivefold decrease than before. The uncertainty in the footprint ranges between 8% to 11% which shows the robustness of the analysis. Although green WF is ignored by most studies, we suggest incorporating it into the accounting. The responsible share of a supply-chain WF to the total blue WF is about 98%, which is quite huge. Water embedded in the hydroelectricity is mainly responsible for such a huge amount of blue WF. Evidently, the use of electricity from hydropower results in the consumption of a large amount of water in exchange for a reduction in carbon emissions. Thus, the article attempts to demonstrate the escalating importance of WF accounting of this mine.

Water use indicators at farm scale - An agro-hydrological software solution

The challenge to sustainably intensify agricultural production in farming systems in face of the increasing variability in regional water resources requires concerted action from many stakeholders, locally, regionally and globally. Models, such as the AgroHyd Farmmodel presented here, can provide information on how farm management decisions affect local water resources at various scales for use in multiple assessment frameworks. It is a stand-alone web-based software that connects agricultural and water-related systems, including all water flows related to farming systems. Results from a case study of the production of 12 crops with rainfed and supplemental irrigation on a farm in northeastern Germany are described here. Indicators that relate the water use to plant production on the farm such as water intensity or water productivity are compared in detail for three consecutive years with greatly varying annual rainfall amounts (from 373 to 790 mm) to highlight the effect of local variability on water flows and indicator values. The discussion illustrates how information on the effect of management decisions, such as crop type, seeding date, crop rotation, cultivation and irrigation on water use can be processed into indicators to help farmers make more effective decisions.

Progress in Water Footprint Assessment: Towards Collective Action in Water Governance

We introduce ten studies in the field of water footprint assessment (WFA) that are representative of the type of papers currently being published in this broad interdisciplinary field. WFA is the study of freshwater use, scarcity, and pollution in relation to consumption, production, and trade patterns. The reliable availability of sufficient and clean water is critical in sustaining the supply of food, energy, and various manufactured goods. Collective and coordinated action at different levels and along all stages of commodity supply chains is necessary to bring about more sustainable, efficient, and equitable water use. In order to position the papers of this volume, we introduce a spectrum for collective action that can give insight in the various ways different actors can contribute to the reduction of the water footprint of human activities. The papers cover different niches in this large spectrum, focusing on different scales of governance and different stages in the supply chain of products. As for future research, we conclude that more research is needed on how actions at different spatial levels and how the different players along supply chains can create the best synergies to make the water footprint of our production and consumption patterns more sustainable.

Large cities get more for less: Water footprint efficiency across the US

Many urban indicators and functional citywide properties have been shown to scale with population due to agglomeration effects. We hypothesize that scaling relations may also exist for water-related urban indicators such as the water footprint. The water footprint is an indicator of water use that measures humans' appropriation of freshwater resources. We analyze the scaling of the water footprint for 65 mid- to large-sized US cities using both empirical estimates and a social interaction network model of city functioning. The network model is used to explain the presence of any scaling exponent in the empirical estimates of the urban water footprint by linking to previous theories of urban scaling. We find that the urban water footprint tends to approximately show sublinear scaling behavior with both population and gross domestic product. Thus, large cities tend to be more water footprint efficient and productive than mid-sized cities, where efficiency and productivity are quantified, in a broad sense, as deviations from a linear scaling exponent. We find the sublinear scaling may be linked to changes in urban economic structure with city size, which lead to large cities shifting water intensive economic activities to less populated regions. In addition, we find that green water contributes to the scaling both positively by transferring the dependence of food consumption on population into the water footprint and negatively by increasing heterogeneity. Overall, the proposed scaling relations allow for the comparison of water footprint efficiency and productivity of cities. Comparing these properties and identifying deviations from the expected behavior has implications for water resources and urban sustainability.

Optimal allocation of physical water resources integrated with virtual water trade in water scarce regions: A case study for Beijing, China

This study provides an innovative application of virtual water trade in the traditional allocation of physical water resources in water scarce regions. A multi-objective optimization model was developed to optimize the allocation of physical water and virtual water resources to different water users in Beijing, China, considering the trade-offs between economic benefit and environmental impacts of water consumption. Surface water, groundwater, transferred water and reclaimed water constituted the physical resource of water supply side, while virtual water flow associated with the trade of five major crops (barley, corn, rice, soy and wheat) and three livestock products (beef, pork and poultry) in agricultural sector (calculated by the trade quantities of products and their virtual water contents). Urban (daily activities and public facilities), industry, environment and agriculture (products growing) were considered in water demand side. As for the traditional allocation of physical water resources, the results showed that agriculture and urban were the two predominant water users (accounting 54% and 28%, respectively), while groundwater and surface water satisfied around 70% water demands of different users (accounting 36% and 34%, respectively). When considered the virtual water trade of eight agricultural products in water allocation procedure, the proportion of agricultural consumption decreased to 45% in total water demand, while the groundwater consumption decreased to 24% in total water supply. Virtual water trade overturned the traditional components of water supplied from different sources for agricultural consumption, and became the largest water source in Beijing. Additionally, it was also found that environmental demand took a similar percentage of water consumption in each water source. Reclaimed water was the main water source for industrial and environmental users. The results suggest that physical water resources would mainly satisfy the consumption of urban and environment, and the unbalance between water supply and demand could be filled by virtual water import in water scarce regions.

Virtual water trade of agri-food products: Evidence from italian-chinese relations

At global scale, the majority of world water withdrawal is for the agricultural sector, with differences among countries depending on the relevance of agri-food sector in the economy. Virtual water and water footprint could be useful to express the impact on the water resources of each production process and good with the objective to lead to a sustainable use of water at a global level. International trade could be connected to the virtual water flows, in fact through commodities importation, water poor countries can save their own water resources. The present paper focuses on the bilateral virtual water flows connected to the top ten agri-food products traded between Italy and China. Comparing the virtual water flow related to the top 10 agri-food products, the virtual water flow from Italy to China is bigger than the water flow in the opposite direction. Moreover, the composition of virtual water flows is different; Italy imports significant amounts of grey water from China, depending on the different environmental strategies adopted by the two selected countries. This difference could be also related to the fact that traded commodities are very different; the 91% of virtual water imported by Italy is connected to crops products, while the 95% of virtual water imported by China is related to the animal products. Considering national water saving and global water saving, appears that Italy imports virtual water from China while China exerts pressure on its water resources to supply the exports to Italy. This result at global scale implies a global water loss of 129.29millionm3 because, in general, the agri-food products are traded from the area with lower water productivity to the area with the higher water productivity.

Land Use for Edible Protein of Animal Origin-A Review

The present period is characterized by a growing world population and a higher demand for more and better quality food, as well as other products for an improved standard of living. In the future, there will be increasingly strong competition for arable land and non-renewable resources such as fossil carbon-sources, water, and some minerals, as well as between food, feed, fuel, fiber, flowers, and fun (6 F's). Proteins of animal origin like milk, meat, fish, eggs and, probably, insects are very valuable sources of essential amino acids, minerals and vitamins, but their production consumes some non-renewable resources including arable land and causes considerable emissions. Therefore, this study´s objective was to calculate some examples of the land use (arable land and grassland) for production of edible animal protein taking into consideration important animal species/categories, levels of plant and animal yields, the latter estimated with and without co-products from agriculture, and the food/biofuel industry in animal feeding. There are large differences between animal species/categories and their potential to produce edible protein depending on many influencing variables. The highest amounts per kilogram body weight are produced by growing broiler chicken followed by laying hens and dairy cows; the lowest yields in edible protein and the highest land need were observed for beef cattle. This review clearly indicates that the production of food of animal origin is a very complex process, and selective considerations, i.e., focusing on single factors, do not provide an assessment that reflects the complexity of the subject.