Water budget fluxes in catchments under grassland and Eucalyptus plantations of different ages

The area with planted forests increased in the last decades and they have an important role in programs to sequester carbon. However, the effects of eucalyptus plantations on water resources in the Southern Grasslands biome are largely unknown, and we herein address water budget fluxes including green and blue flows. We evaluated green (canopy interception and evapotranspiration) and blue (discharge) water flows in three watersheds; two predominantly covered with Eucalyptus, either in the first years after planting or at the end of the rotation, and one with livestock-grazing grassland. We used field measurements of rainfall, streamflow and throughfall, and estimated canopy interception and evapotranspiration by water balance. Water flows in the monitored watersheds with eucalyptus plantations were influenced by forest development stage. Annual canopy interception and transpiration were always higher in the watersheds with eucalyptus than in the one with grassland, except for the transpiration in the first year after plantation in watershed with young eucalyptus. Increase in evapotranspiration (green water flow) and the consequent decrease in streamflow (blue water flow) should be considered in local water resources management. Studies on catchment hydrology and forest management for improved water use efficiency and streamflow regulation are required, particularly in understudied regions.

Download Full-text

Dynamics of green and blue water flows and their controlling factors in Heihe River basin of northwestern China

10.5194/hess-2016-241 ◽

2016 ◽

Author(s):

Kaisheng Luo ◽

Fulu Tao

Keyword(s):

Water Resources ◽

River Basin ◽

Water Flow ◽

Heihe River Basin ◽

Green Water ◽

Heihe River ◽

Blue Water ◽

Water Flows ◽

Green And Blue Water ◽

County Scale

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.

Download Full-text

A step forward toward the high-resolution assessment of virtual water flows at the company’s scale

10.5194/egusphere-egu21-14900 ◽

2021 ◽

Author(s):

Elena De Petrillo ◽

Marta Tuninetti ◽

Francesco Laio

Keyword(s):

Water Management ◽

High Resolution ◽

Water Resources ◽

Virtual Water ◽

The State ◽

Green Water ◽

Blue Water ◽

Food Trade ◽

Water Flows ◽

Final Consumer

Through the international trade of agricultural goods, water resources that are physically used in the country of production are virtually transferred to the country of consumption. Food trade leads to a global redistribution of freshwater resources, thus shaping distant interdependencies among countries. Recent studies have shown how agricultural trade drives an outsourcing of environmental impacts pertaining to depletion and pollution of freshwater resources, and eutrophication of river bodies in distant producer countries. What is less clear is how the final consumer &#8211; being an individual, a company, or a community- impacts the water resources of producer countries at a subnational scale. Indeed, the variability of sub-national water footprint (WF in m3/tonne) due to climate, soil properties, irrigation practices, and fertilizer inputs is generally lost in trade analyses, as most trade data are only available at the country scale. The latest version of the Spatially Explicit Information on Production to Consumption Systems model&#160; (SEI-PCS) by Trase provides detailed data on single trade flows (in tonne) along the crop supply chain: from local municipalities- to exporter companies- to importer companies &#8211; to the final consumer countries. These data allow us to capitalize on the high-resolution data of agricultural WF available in the literature, in order to quantify the sub-national virtual water flows behind food trade. As a first step, we assess the detailed soybean trade between Brazil and Italy. This assessment is relevant for water management because the global soybean flow reaching Italy may be traced back to 374 municipalities with heterogeneous agricultural practises and water use efficiency. Results show that the largest flow of virtual water from a Brazilian municipality to Italy -3.52e+07 m3 (3% of the total export flow)- comes from Sorriso in the State of Mato Grosso. Conversely, the highest flow of blue water -1.56e+05 m3- comes from Jaguar&#227;o, in the State of Rio Grande do Sul, located in the Brazilian Pampa. Further, the analysis at the company scale reveals that as many as 37 exporting companies can be identified exchanging to Italy; &#160;Bianchini S.A is the largest virtual water trader (1.88 e+08 m3 of green water and 3,92 e+06 m3 of blue water), followed by COFCO (1,06 e+08 m3 of green water and 6.62 m3 of blue water) &#160;and Cargill ( 6.96 e+07 m3 of green water and 2.80 e+02 m3 of blue water). By building the bipartite network of importing companies and municipalities originating the fluxes we are able to efficiently disaggregate the supply chains , providing novel tools to build sustainable water management strategies.

Download Full-text

Water saving through international trade of agricultural products

Hydrology and Earth System Sciences ◽

10.5194/hess-10-455-2006 ◽

2006 ◽

Vol 10 (3) ◽

pp. 455-468 ◽

Cited By ~ 250

Author(s):

A. K. Chapagain ◽

A. Y. Hoekstra ◽

H. H. G. Savenije

Keyword(s):

Water Resources ◽

Water Use ◽

Virtual Water ◽

Water Saving ◽

Agricultural Products ◽

Green Water ◽

Blue Water ◽

Water Flows ◽

Global Water ◽

National Water

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.

Download Full-text

Quantifying the Effect of Land Use Change and Climate Variability on Green Water Resources in the Xihe River Basin, Northeast China

Sustainability ◽

10.3390/su11020338 ◽

2019 ◽

Vol 11 (2) ◽

pp. 338 ◽

Cited By ~ 2

Author(s):

Leting Lyu ◽

Xiaorui Wang ◽

Caizhi Sun ◽

Tiantian Ren ◽

Defeng Zheng

Keyword(s):

Land Use ◽

Water Resources ◽

Land Use Change ◽

Climate Variability ◽

River Basin ◽

Water Flow ◽

Water Storage ◽

Green Water ◽

Efficiency Coefficient ◽

Relative Change

Based on a land use interpretation and distributed hydrological model, soil and water assessment tool (SWAT), this study simulated the hydrological cycle in Xihe River Basin in northern China. In addition, the influence of climate variability and land use change on green water resources in the basin from 1995 to 2015 was analyzed. The results show that (1) The ENS (Nash-Sutcliffe model efficiency coefficient) and R2 (coefficient of determination) were 0.94 and 0.89, respectively, in the calibration period, and 0.89 and 0.88, respectively, in the validation period. These indicate high simulation accuracy; (2) Changes in green water flow and green water storage due to climate variability accounted for increases of 2.07 mm/a and 1.28 mm/a, respectively. The relative change rates were 0.49% and 0.9%, respectively, and the green water coefficient decreased by 1%; (3) Changes in green water flow and green water storage due to land use change accounted for increases of 69.15 mm and 48.82 mm, respectively. The relative change rates were 16.4% and 37.2%, respectively, and the green water coefficient increased by 10%; (4) Affected by both climate variability and land use change, green water resources increased by 121.3 mm and the green water coefficient increased by 9% in the Xihe River Basin. It is noteworthy that the influence of land use change was greater than that of climate variability.

Download Full-text

Impacts of human activities and climate variability on green and blue water flows in the Heihe River Basin in Northwest China

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-9477-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 9477-9504 ◽

Cited By ~ 15

Author(s):

C. Zang ◽

J. Liu ◽

L. Jiang ◽

D. Gerten

Keyword(s):

Climate Variability ◽

River Basin ◽

Water Flow ◽

Human Activities ◽

Northwest China ◽

Green Water ◽

Heihe River ◽

Blue Water ◽

Water Flows ◽

Green And Blue Water

Abstract. Human activities and climate factors both affect the availability of water resources and the sustainability of water management. Especially in already dry regions, water has become more and more scarce with increasing requirements from growing population, economic development and diet shifts. Although progress has been made in understanding variability of runoff, the impacts of climate variability and human activities on flows of both green water (actual evapotranspiration) and blue water (discharge accumulated in the river network) remain less well understood. We study the spatial patterns of blue and green water flows and the impacts on them of human activities and climate variability as simulated by the Soil and Water Assessment Tool (SWAT) for an inland Heihe river basin located in Northwest China. The results show that total green and blue water flow increased from 1980 to 2005, mainly as a result of climate variability (upward precipitation trends). Direct human activities did not significantly change the total green and blue water flow. However, land use change led to a transformation of 206 million m3 from green to blue water flow, while farmland irrigation expansion resulted in a transformation of 66 million m3 from blue to green water flow. The synchronous climate variability caused an increase of green water flow by 469 million m3 and an increase of blue water flow by 146 million m3 at the river basin level, while the geographical distribution showed an uneven change even with reductions of water flows in western sub-basins at midstream. The results are helpful to benchmark the water resources in the context of global change in the inland river basins in China. This study also provides a general approach to investigate the impacts of historical human activities and climate variability on green and blue water flows at the river basin level.

Download Full-text

Integrating blue and green water flows for water resources management and planning

Physics and Chemistry of the Earth Parts A/B/C ◽

10.1016/j.pce.2006.08.033 ◽

2006 ◽

Vol 31 (15-16) ◽

pp. 753-762 ◽

Cited By ~ 39

Author(s):

Graham Jewitt

Keyword(s):

Water Resources ◽

Water Resources Management ◽

Green Water ◽

Resources Management ◽

Water Flows

Download Full-text

Impact of Grain for Green Project on Water Resources and Ecological Water Stress in Yanhe River Basin

10.1101/2021.10.25.465705 ◽

2021 ◽

Author(s):

Yuping Han ◽

Fan Xia ◽

Huiping Huang ◽

Wenbin Mu

Keyword(s):

Land Use ◽

Water Stress ◽

Water Resources ◽

Water Flow ◽

Green Water ◽

Stress Index ◽

Grain For Green ◽

Water Stress Index ◽

Grain For Green Project ◽

Regional Water

Grain for Green project (GGP) initialed by China government since 1999 has achieved substantial achievements accompanied with surface runoff decrease in the Loess Plateau but impacts of large-scale afforestation on regional water resources are uncertain. Hence, the objective of this study is to explore the impact of land use change on generalized water resources and ecological water stress using blue and green water concept taking Yanhe River Basin as a case study. Soil and Water Assessment Tool (SWAT) is applied to quantify summary of green and blue water which is defined as generalized water resources, ecological water requirement of vegetation (forest and grass), agricultural water footprint and virtual water flow are considered as regional water requirements. Land use types of 1980 (scenario?), 2017 (scenario?) are input in SWAT model while keeps other parameters constant in order to isolate the influence of land use changes. Results show that average annual difference of blue, green and generalized water resources is -72.08 million m 3 , 24.34 million m 3 , -47.74 million m 3 respectively when simulation results of scenario? subtracts scenario?and it presents that land use change caused by GGP leads to decrease in blue and generalized water resources whereas increase in green water resources. SURQ in scenario?is more than that in scenario?in all the study period from 1980-2017, green water storage in scenario?is more than that in scenario? in all the study period except in 1998; whereas LATQ in scenario?is less than that in scenario? except in 2000 and 2015, GWQ in 1992, 2000 and 2015, green water flow in 1998. Blue water, green water storage and green water flow in scenario? is less than that in scenario?in the whole basin, 12.89 percent of the basin and 99.21 percent of the basin respectively. Total WF increases from 1995 to 2010 because forest WF increases significantly in this period though agricultural WF and grass WF decreases. Ecological water stress index has no obvious temporal change trend in both land use scenarios but ecological water stress index in scenario? is more than that in scenario?which illustrates that GGP leads to increase of ecological water stress from perspective of generalized water resources

Download Full-text

Impact of Climate Variability on Blue and Green Water Flows in the Erhai Lake Basin of Southwest China

Water ◽

10.3390/w11030424 ◽

2019 ◽

Vol 11 (3) ◽

pp. 424 ◽

Cited By ~ 8

Author(s):

Zhe Yuan ◽

Jijun Xu ◽

Xianyong Meng ◽

Yongqiang Wang ◽

Bo Yan ◽

...

Keyword(s):

Spatial Distribution ◽

Water Flow ◽

Green Water ◽

Lake Basin ◽

Erhai Lake ◽

Climate Change Scenarios ◽

Blue Water ◽

Water Flows ◽

Basin Scale ◽

Precipitation And Temperature

The Erhai Lake Basin is a crucial water resource of the Dali prefecture. This research used the soil and water assessment tool (SWAT) and the China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS) to estimate blue and green water flows. Then the spatial and temporal change of blue and green water flows was investigated. With the hypothetical climate change scenarios, the sensitivity of blue and green water flows to precipitation and temperature has also been analyzed. The results showed that: (1) The CMADS reanalysis dataset can capture the observed probability density functions for daily precipitation and temperature. Furthermore, the CMADS performed well in monthly variables simulation with relative bias and absolute bias less than 7% and 0.5 °C for precipitation and temperature, respectively; (2) blue water flow has increased while green water flow has decreased during 2009 to 2016. The spatial distribution of blue water flow was uneven in the Erhai Lake Basin with the blue water flow increased from low altitudes to mountain areas. While the spatial distribution of green water flow was more homogeneous; (3) a 10% increase in precipitation can bring a 20.8% increase in blue water flow with only a 2.5% increase in green water flow at basin scale. When temperature increases by a 1.0 °C, the blue water flow and green water flow changes by −3% and 1.7%, respectively. Blue and green water flows were more sensitive to precipitation in low altitude regions. In contrast, the water flows were more sensitive to temperature in the mountainous area.

Download Full-text

Simulation of blue and green water resources in the Wei River basin, China

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-364-486-2014 ◽

2014 ◽

Vol 364 ◽

pp. 486-491 ◽

Cited By ~ 1

Author(s):

Z. Xu ◽

D. Zuo

Keyword(s):

Water Resources ◽

River Basin ◽

Water Flow ◽

Yellow River ◽

Water Storage ◽

Green Water ◽

Blue Water ◽

The Wei River Basin ◽

Wei River Basin ◽

Wei River

Abstract. The Wei River is the largest tributary of the Yellow River in China and it is suffering from water scarcity and water pollution. In order to quantify the amount of water resources in the study area, a hydrological modelling approach was applied by using SWAT (Soil and Water Assessment Tool), calibrated and validated with SUFI-2 (Sequential Uncertainty Fitting program) based on river discharge in the Wei River basin (WRB). Sensitivity and uncertainty analyses were also performed to improve the model performance. Water resources components of blue water flow, green water flow and green water storage were estimated at the HRU (Hydrological Response Unit) scales. Water resources in HRUs were also aggregated to sub-basins, river catchments, and then city/region scales for further analysis. The results showed that most parts of the WRB experienced a decrease in blue water resources between the 1960s and 2000s, with a minimum value in the 1990s. The decrease is particularly significant in the most southern part of the WRB (Guanzhong Plain), one of the most important grain production basements in China. Variations of green water flow and green water storage were relatively small on the spatial and temporal dimensions. This study provides strategic information for optimal utilization of water resources and planning of cultivating seasons in the Wei River basin.

Download Full-text

Estimating surface water and vadose water resources for an ungauged inland catchment in Vietnam

Journal of Water and Climate Change ◽

10.2166/wcc.2021.343 ◽

2021 ◽

Author(s):

Liem Duy Nguyen ◽

Phuong Dong Nguyen Dang ◽

Loi Kim Nguyen

Keyword(s):

Water Resources ◽

Water Flow ◽

Water Discharge ◽

Water Storage ◽

Green Water ◽

Weather Data ◽

Coefficient Of Determination ◽

Blue Water ◽

Time Step ◽

Statistical Measures

Abstract This study aimed to assess water resources for the La Vi catchment, an ungauged inland basin in Vietnam. An Internet of Things-based automatic meteorological station has been installed in the catchment to record hourly weather data from 2016. By comparing water level observations with limited discharge measurements, discharges from November 2015 to February 2018 were calculated at Tan Hoa bridge using the slope-area method. The Soil and Water Assessment Tool was calibrated and validated for the wet season of 2015 and 2017, respectively, using the previously calculated water discharges. Statistical measures including Nash–Sutcliffe index, percent bias, and coefficient of determination indicated the satisfactory performance of the model in simulating water discharge on daily time step during both periods. The results of the water resources assessment in the catchment showed that the annual average of blue water flow, green water flow, and green water storage reached 1,596.50, 371.13, and 15.36 mm, respectively. The blue water flow reached a higher value in the center of the catchment. Meanwhile, the high-value areas of green water flow and green water storage were in the western upstream and the riverside downstream. These findings could provide a valuable scientific foundation for sustainable watershed management.

Download Full-text