scholarly journals Assessing Green and Blue Water: Understanding Interactions and Making Balance between Human and Nature

2018 ◽  
Author(s):  
Ganquan Mao ◽  
Junguo Liu ◽  
Feng Han ◽  
Ying Meng ◽  
Yong Tian ◽  
...  

Abstract. Water resources assessment is crucial for human well-being and ecosystem’s health. Assessments by considering both the blue and green water are of great significance as the green water plays a critical but often ignored role in the terrestrial ecosystem, especially in arid and semi-arid regions. Many approaches have been developed for green and blue water valuation, while few of them considers the interrelationship between them. This study proposed a new framework for green and blue water assessment by considering the interactions between them in an arid endorheic river basin where hydrological cycling is dramatically altered by human activities. Results show that even though the green water is the dominant water resources, the blue water is also critical. Most of the blue water are transformed to green water through physically and human induced processes to meet the water demand of ecosystems. Time and spatial variability of water supply and consumption forms totally different blue and green water regimes in different ecosystems. We also found that human use an increasing share of water with the decrease of the water availability. The massive water use by human reduces the water use for natural ecosystems. This indicates that natural ecosystems will take a higher risk of freshwater use when the water use competition increases. This study provides crucial information to better understand the interactions between green and blue water by assessing water resources in an explicit way. It also provides crucial implications for water management aiming to make the balance between humankind and nature.

2006 ◽  
Vol 10 (3) ◽  
pp. 455-468 ◽  
Author(s):  
A. K. Chapagain ◽  
A. Y. Hoekstra ◽  
H. H. G. Savenije

Abstract. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm3/yr. These products are however being produced with only 1253 Gm3/yr in the exporting countries, saving global water resources by 352 Gm3/yr. This saving is 28 per cent of the international virtual water flows related to the trade of agricultural products and 6 per cent of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm3/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm3/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.


2020 ◽  
Author(s):  
Raj Deva Singh ◽  
Kumar Ghimire ◽  
Ashish Pandey

<p>Nepal is an agrarian country and almost one-third of Gross Domestic Product (GDP) is dependent on agricultural sector. Koshi river basin is the largest basin in the country and serves large share on agricultural production. Like another country, Nepalese agriculture holds largest water use in agriculture. In this context, it is necessary to reduce water use pressure. In this study, water footprint of different crop (rice, maize, wheat, millet, sugarcane, potato and barley) have been estimated for the year 2005 -2014 to get the average water footprint of crop production during study period. CROPWAT model, developed by Food and Agriculture Organization (FAO 2010b).</p><p>For the computation of the green and blue water footprints, estimated values of ET (the output of CROPWAT model) and yield (derived from statistical data) are utilised. Blue and green water footprint are computed for different districts (16 districts within KRB) / for KRB in different years (10 years from 2005 to 2014) and crops (considered 7 local crops). The water footprint of crops production for any district or basin represents the average of WF production of seven crops in the respective district or basin.</p><p>The study provides a picture of green and blue water use in crop production in the field and reduction in the water footprint of crop production by selecting suitable crops at different places in the field. The Crop, that has lower water footprint, can be intensified at that location and the crops, having higher water footprint, can be discontinued for production or measure for water saving technique needs to be implemented reducing evapotranspiration. The water footprint of agriculture crop production can be reduced by increasing the yield of the crops. Some measures like use of an improved variety of seed, fertilizer, mechanized farming and soil moisture conservation technology may also be used to increase the crop yields.</p><p>The crop harvested areas include both rainfed as well as irrigated land. Agricultural land occupies 22% of the study area, out of which 94% areas are rainfed whereas remaining 6% areas are under irrigation. The study shows 98% of total water use in crop production is due to green water use (received from rainfall) and remaining 2 % is due to blue water use received from irrigation (surface and ground water as source). Potato has 22% blue water proportion and contributes 85% share to the total blue water use in the basin. Maize and rice together hold 77% share of total water use in crops production. The average annual water footprint of crop production in KRB is 1248 cubic meter/ton having the variation of 9% during the period of 2005-2014. Sunsari, Dhankuta districts have lower water footprint of crop production. The coefficient of variation of water footprint of millet crop production is lower as compared to those of other crops considered for study whereas sugarcane has a higher variation of water footprint for its production.</p>


2021 ◽  
Author(s):  
Hamideh Nouri ◽  
Sattar Chavoshi Borujeni ◽  
Pamela Nagler ◽  
Armando Barreto Munoz ◽  
Kamel Didan ◽  
...  

<p>The concept of a sustainable green city based on Sustainable Development Goals (SDGs)–Goal 11 - sustainable cities and communities – may not be narrowed down to solely intensifying urban green spaces. Sustainability could include urban water management to alleviate possible conflict among “water‐saving” and “greening cities” strategies. Water consumption by urban greenery has a major role in urban water management, particularly in water-scarce regions where green covers are most affected by drought and aridity. More green and blue water resources are required to maintain and expand urban green spaces. Quantifying the water footprint of urban greenery helps to balance greening cities while water saving from both green and blue water resources. We employed remote sensing and artificial intelligence techniques to assess the water consumption and water footprint of a 780‐ha public green space, the Adelaide Parklands in Australia. We estimated the green and blue water footprint of this green space (containing 29 parks) during 2010-2018 on a monthly basis. Our results showed that the mean total water footprint of the Adelaide Parklands was about 7.75 gigaliter per annum over 2010-2018; it varied from 7.19 gigaliter/year in 2018 to 8.45 gigaliter/year in 2012. The blue water footprint was consistently higher than the green water footprint even in wet time of the year. We suggest implementing sponge city and water sensitive urban design (WSUD) techniques to help greening cities while reducing the water footprint of urban green spaces. These approaches have the potential to lessen the pressure on blue water resources and optimise the consumption of green water resources.</p>


2021 ◽  
Vol 13 (4) ◽  
pp. 2193
Author(s):  
Junchao Jiang ◽  
Leting Lyu ◽  
Yuechi Han ◽  
Caizhi Sun

Over 80% of global grain production relies on green water, water from precipitation that is stored in unsaturated soil and supports plant growth. Blue water, precipitation that turns into surface water and groundwater, is also a vital surface water resource, and it can be directly utilized. The Tanghe River Basin is a typical temperate continental monsoon watershed in Northern China where residents and crops rely on blue and green water resources. In this study, the spatiotemporal distributions of water resources in the Tanghe River Basin were simulated using the soil and water assessment tool (SWAT) model for the period between 1970 and 2015. The results demonstrate that the Nash–Sutcliffe efficiency and coefficient of determination were both higher than 0.64 during the calibration and validation periods at all hydrological stations, indicating high simulation accuracy. The average annual water resources of the Tanghe River Basin are 759.37 mm. Green and blue water account for 68% and 32% of the total water resources, respectively. The study period was divided into the reference period (1970–1976) and the variation period (1977–2015), to explore the impact of climate change on the green and blue water resources of the Tanghe River Basin water resources. Compared with the reference period, the average green and blue water resources in the variation period decreased by 78.48 and 35.94 mm/year, and their rate changes were −13.45% and −13.17%, respectively. The water resource relative change rates were high in the south and low in the north, and they were predominantly affected by precipitation. This study improves our understanding of the hydrological processes as well as the availability of blue and green water in the study region, and can prove beneficial in promoting the sustainable development of small basins and the integrated watershed management in areas with similar climatic conditions.


2016 ◽  
Vol 20 (6) ◽  
pp. 2179-2194 ◽  
Author(s):  
Michael J. Lathuillière ◽  
Michael T. Coe ◽  
Mark S. Johnson

Abstract. The Amazon Basin is a region of global importance for the carbon and hydrological cycles, a biodiversity hotspot, and a potential centre for future economic development. The region is also a major source of water vapour recycled into continental precipitation through evapotranspiration processes. This review applies an ecohydrological approach to Amazonia's water cycle by looking at contributions of water resources in the context of future agricultural production. At present, agriculture in the region is primarily rain-fed and relies almost exclusively on green-water resources (soil moisture regenerated by precipitation). Future agricultural development, however, will likely follow pathways that include irrigation from blue-water sources (surface water and groundwater) as insurance from variability in precipitation. In this review, we first provide an updated summary of the green–blue ecohydrological framework before describing past trends in Amazonia's water resources within the context of land use and land cover change. We then describe green- and blue-water trade-offs in light of future agricultural production and potential irrigation to assess costs and benefits to terrestrial ecosystems, particularly land and biodiversity protection, and regional precipitation recycling. Management of green water is needed, particularly at the agricultural frontier located in the headwaters of major tributaries to the Amazon River, and home to key downstream blue-water users and ecosystem services, including domestic and industrial users, as well as aquatic ecosystems.


2016 ◽  
Author(s):  
Kaisheng Luo ◽  
Fulu Tao

Abstract. Climate variation will affect hydrological cycle, as well as the availability of water resources. In spite of large progresses have been made in the dynamics of hydrological cycle variables, the dynamics and drivers of blue water flow, green water flow and total flow (three flows), as well as the proportion of green water (GWC), in the past and future at county scale, were scarcely investigated. In this study, taking the Heihe River basin in China as an example, we investigated the dynamics of green and blue water flows and their controlling factors during 1980–2009 using five statistical approaches and the Soil and Water Assessment Tool (SWAT). We found that there were large variations in the dynamics of green and blue water flows during 1980–2009 at the county scale. Three flows in all counties showed an increasing trend except Jiayuguan and Jianta county. The GWC showed a downward trend in the Qilian, Suzhou, Shandan, Linze and Gaotai counties, but an upward trend in the Mingle, Sunan, Jinta, Jiayuguan, Ganzhou and Ejilaqi counties. In all the counties, the three flows and GWC had strong persistent trends in the future, which are mainly ascribed to rainfall variation. In the Qilian and Shandan counties, rainfall was the major controlling factor for the three flows and GWC. Rainfall controlled the green water and total flows in the Mingle, Linze and Gaotai counties; green water flow and GWC in the Suzhou county; green water flow, total flow and GWC in the Jinta and Ejilaqi counties. Our results also showed that the "Heihe River basin allocation project" had significant influences on the abrupt changes of the flows above-mentioned. Our results illustrate the status of the water resources at county scale, providing a reference for water resources management of inland river basins.


Author(s):  
Maite M. Aldaya ◽  
M. Ramón Llamas ◽  
Arjen Y. Hoekstra

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Environmental Science. Please check back later for the full article. The water footprint concept broadens the scope of traditional national and corporate water accounting as it has been previously known. It highlights the ways in which water consuming and polluting activities relate to the structure of the global economy, opening a window of opportunity to increase transparency and improve water management along whole-production and supply chains. This concept adds a new dimension to integrated water resources management in a globalized world. The water footprint is a relatively recent indicator. Created in 2002, it aims to quantify the effect of consumption and trade on the use of water resources. Specifically, the water footprint is an indicator of freshwater use that considers both direct and indirect water use of a consumer or producer. For instance, the water footprint of a product refers to the volume of freshwater used to produce the product, tracing the origin of raw material and ingredients along their respective supply chains. This novel indirect component of water use in supply chains is, in many cases, the greatest share of water use, for example, in the food and beverage sector and the apparel industry. Water footprint assessment shows the full water balance, with water consumption and pollution components specified geographically and temporally and with water consumption specified by type of source (e.g., rainwater, groundwater, or surface water). It introduces three components: 1. The blue water footprint refers to the consumption of blue water resources (i.e., surface and groundwater including natural freshwater lakes, manmade reservoirs, rivers, and aquifers) along the supply chain of a product, versus the traditional and restricted water withdrawal measure. 2. The green water footprint refers to consumption through transpiration or evaporation of green water resources (i.e., soilwater originating from rainwater). Green water maintains natural vegetation (e.g., forests, meadows, scrubland, tundra) and rain-fed agriculture, yet plays an important role in most irrigated agriculture as well. Importantly, this kind of water is not quantified in most traditional agricultural water use analyses. 3. The grey water footprint refers to pollution and is defined as the volume of freshwater that is required to assimilate the load of pollutants given natural concentrations for naturally occurring substances and existing ambient water-quality standards. The water footprint concept has been incorporated into public policies and international standards. In 2011, the Water Footprint Network adopted the Water Footprint Assessment Manual, which provides a standardized method and guidelines. In 2014, the International Organization for Standardization adopted a life cycle-based ISO 14046 standard for the water footprint; it offers guidelines to integrate water footprint analysis in life-cycle assessment for products. In practice, water footprint assessment generally results in increased awareness of critical elements in a supply chain, such as hotspots that deserve most attention, and what can be done to improve water management in those hotspots. Water footprint assessment, including the estimation of virtual water trade, applied in different countries and contexts, is producing new data and bringing larger perspectives that, in many cases, lead to a better understanding of the drivers behind water scarcity.


2005 ◽  
Vol 2 (6) ◽  
pp. 2219-2251 ◽  
Author(s):  
A. K. Chapagain ◽  
A. Y. Hoekstra ◽  
H. H. G. Savenije

Abstract. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm3/yr. These products are however being produced with only 1253 Gm3/yr in the exporting countries, saving global water resources by 352 Gm3/yr. This saving is 28% of the international virtual water flows related to the trade of agricultural products and 6% of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm3/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm3/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.


2021 ◽  
Vol 3 ◽  
Author(s):  
Kul Khand ◽  
Gabriel B. Senay ◽  
Stefanie Kagone ◽  
Gabriel Edwin Lee Parrish

Global food and water insecurity could be serious problems in the upcoming decades with growing demands from the increasing global population and more frequent effect of climatic extremes. As the available water resources are diminishing and facing continuous stress, it is crucial to monitor water demand and water availability to understand the associated water stresses. This study assessed the water stress by applying the water supply stress index (WaSSI) in relation to green (WaSSIG) and blue (WaSSIB) water resources across six major cropland basins including the Mississippi (North America), San Francisco (South America), Nile (Africa), Danube (Europe), Ganges-Brahmaputra (Asia), and Murray-Darling (Australia) for the past 17-years (2003–2019). The WaSSIG and WaSSIB results indicated that the Murray-Darling Basin experienced the most severe (maximum WaSSIG and WaSSIB anomalies) green and blue water stresses and the Mississippi Basin had the least. All basins had both green and blue water stresses for at least 35% (6 out of 17 years) of the study period. The interannual variations in green water stress were driven by both crop water demand and green water supply, whereas the blue water stress variations were primarily driven by blue water supply. The WaSSIG and WaSSIB provided a better understanding of water stress (blue or green) and their drivers (demand or supply driven) across cropland basins. This information can be useful for basin-specific resource mobilization and interventions to ensure food and water security.


2016 ◽  
Author(s):  
Michael J. Lathuillière ◽  
Michael T. Coe ◽  
Mark S. Johnson

Abstract. The Amazon Basin is a region of global importance for the carbon and hydrological cycles, a biodiversity hotspot, and a potential centre for future economic development. The region is also a major source of water vapour recycled into continental precipitation through evapotranspiration processes. This review applies an ecohydrological approach to Amazonia's water cycle by looking at contributions of water resources in the context of future agricultural production. At present, agriculture in the region is primarily rain-fed and relies almost exclusively on green water resources (soil moisture regenerated by precipitation). Future agricultural development, however, will likely follow pathways that include irrigation from blue water sources (surface and groundwater) as insurance from variability in precipitation. In this review, we first provide an updated summary of the ecohydrological framework before describing past trends in Amazonia's green and blue water resources within the context of land use and land cover change. We then describe green and blue water trade-offs in light of future agricultural production and potential irrigation to assess costs and benefits to terrestrial ecosystems, particularly land and biodiversity protection, and regional precipitation recycling. Management of green water is needed, particularly at the agricultural frontier located in the headwaters of major tributaries to the Amazon River, and home to key downstream blue water users and ecosystem services, including domestic and industrial users, as well as aquatic ecosystems.


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