Assessment of Water Footprint for Koshi River Basin (KRB), Nepal

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>

2011 ◽  
Vol 8 (1) ◽  
pp. 763-809 ◽  
Author(s):  
M. M. Mekonnen ◽  
A. Y. Hoekstra

Abstract. This study quantifies the green, blue and grey water footprint of global crop production in a spatially-explicit way for the period 1996–2005. The assessment is global and improves upon earlier research by taking a high-resolution approach, estimating the water footprint of 126 crops at a 5 by 5 arc min grid. We have used a grid-based dynamic water balance model to calculate crop water use over time, with a time step of one day. The model takes into account the daily soil water balance and climatic conditions for each grid cell. In addition, the water pollution associated with the use of nitrogen fertilizer in crop production is estimated for each grid cell. The crop evapotranspiration of additional 20 minor crops is calculated with the CROPWAT model. In addition, we have calculated the water footprint of more than two hundred derived crop products, including various flours, beverages, fibres and biofuels. We have used the water footprint assessment framework as in the guideline of the water footprint network. Considering the water footprints of primary crops, we see that global average water footprint per ton of crop increases from sugar crops (roughly 200 m3 ton−1), vegetables (300 m3 ton−1), roots and tubers (400 m3 ton−1), fruits (1000 m3 ton−1), cereals} (1600 m3 ton−1), oil crops (2400 m3 ton−1) to pulses (4000 m3 ton−1). The water footprint varies, however, across different crops per crop category and per production region as well. Besides, if one considers the water footprint per kcal, the picture changes as well. When considered per ton of product, commodities with relatively large water footprints are: coffee, tea, cocoa, tobacco, spices, nuts, rubber and fibres. The analysis of water footprints of different biofuels shows that bio-ethanol has a lower water footprint (in m3 GJ−1) than biodiesel, which supports earlier analyses. The crop used matters significantly as well: the global average water footprint of bio-ethanol based on sugar beet amounts to 51 m3 GJ−1, while this is 121 m3 GJ−1 for maize. The global water footprint related to crop production in the period 1996–2005 was 7404 billion cubic meters per year (78% green, 12% blue, 10% grey). A large total water footprint was calculated for wheat (1087 Gm3 yr−1), rice (992 Gm3 yr−1) and maize (770 Gm3 yr−1). Wheat and rice have the largest blue water footprints, together accounting for 45% of the global blue water footprint. At country level, the total water footprint was largest for India (1047 Gm3 yr−1), China (967 Gm3 yr−1) and the USA (826 Gm3 yr−1). A relatively large total blue water footprint as a result of crop production is observed in the Indus River Basin (117 Gm3 yr−1) and the Ganges River Basin (108 Gm3 yr−1). The two basins together account for 25% of the blue water footprint related to global crop production. Globally, rain-fed agriculture has a water footprint of 5173 Gm3 yr−1 (91% green, 9% grey); irrigated agriculture has a water footprint of 2230 Gm3 yr−1 (48% green, 40% blue, 12% grey).


Author(s):  
J. Ramachandran ◽  
R. Lalitha ◽  
S. Vallal Kannan ◽  
K. Sivasubramanian

Background: Water Footprint is a recently used indicator which helps to reduce water depletion and alleviate water stress in areas of drought and proper crop cultivation. Hence a study was taken up to assess the crop water footprint of different groundnut varieties namely TMV 7, VRI 2, VRI 3, VRI Gn 5, VRI Gn 6, CO 3, CO Gn 4, ALR 3 and TMV Gn 13 cultivated during Kharif and Rabi seasons at Tiruchirapalli district of Tamil Nadu. Methods: The total water requirement, blue and green crop evapotranspiration, blue and green crop water use and total water footprint for different varieties of groundnut were estimated using CROPWAT 8.0 Windows. A comparison was made between the water footprint of groundnut varieties and the strategies to reduce water footprint is presented. Result: The total water footprint for groundnut varieties ranged from 2603 to 4889 m3 ton-1 (CV of 26%) during kharif season, while it was ranged from 1465 to 2470 m3 ton-1 (CV of 18%) during rabi season. It was found that in all groundnut varieties the blue water footprint is higher than the green water footprint, while VRI Gn 5 variety had minimum total water footprint. It was concluded that, the groundnut production is affected by different levels of blue water stress which requires effective irrigation practices and water management strategies to enhance the crop production.


2014 ◽  
Vol 18 (8) ◽  
pp. 3165-3178 ◽  
Author(s):  
X. C. Cao ◽  
P. T. Wu ◽  
Y. B. Wang ◽  
X. N. Zhao

Abstract. The aim of this study is to estimate the green and blue water footprint (WF) and the total water use (TWU) of wheat crop in China in both irrigated and rainfed productions. Crop evapotranspiration and water evaporation loss are both considered when calculating the water footprint in irrigated fields. We compared the water use for per-unit product between irrigated and rainfed crops and analyzed the relationship between promoting the yield and conserving water resources. The national total and per-unit-product WF of wheat production in 2010 were approximately 111.5 Gm3 (64.2% green and 35.8% blue) and 0.968 m3 kg−1, respectively. There is a large difference in the water footprint of the per-kilogram wheat product (WFP) among different provinces: the WFP is low in the provinces in and around the Huang–Huai–Hai Plain, while it is relatively high in the provinces south of the Yangtze River and in northwestern China. The major portion of WF (80.9%) comes from irrigated farmland, and the remaining 19.1% is rainfed. Green water dominates the area south of the Yangtze River, whereas low green water proportions are found in the provinces located in northern China, especially northwestern China. The national TWU and total water use of the per-kilogram wheat product (TWUP) are 142.5 Gm3 and 1.237 m3 kg−1, respectively, containing approximately 21.7% blue water percolation (BWp). The values of WFP for irrigated (WFPI) and rainfed (WFPR) crops are 0.911 and 1.202 m3 kg−1, respectively. Irrigation plays an important role in food production, promoting the wheat yield by 170% and reducing the WFP by 24% compared to those of rainfed wheat production. Due to the low irrigation efficiency, more water is needed per kilogram in irrigated farmland in many arid regions, such as the Xinjiang, Ningxia and Gansu Provinces. We divided the 30 provinces of China into three categories according to the relationship between the TWUPI (TWU for per-unit product in irrigated farmland) and TWUPR (TWU for per-unit product in rainfed farmland): (I) TWUPI < TWUPR, (II) TWUPI = TWUPR, and (III) TWUPI > TWUPR. Category II, which contains the major wheat-producing areas in the North China Plain, produces nearly 75% of the wheat of China. The double benefits of conserving water and promoting production can be achieved by irrigating wheat in Category I provinces. Nevertheless, the provinces in this category produce only 1.1% of the national wheat yield.


2011 ◽  
Vol 15 (5) ◽  
pp. 1577-1600 ◽  
Author(s):  
M. M. Mekonnen ◽  
A. Y. Hoekstra

Abstract. This study quantifies the green, blue and grey water footprint of global crop production in a spatially-explicit way for the period 1996–2005. The assessment improves upon earlier research by taking a high-resolution approach, estimating the water footprint of 126 crops at a 5 by 5 arc minute grid. We have used a grid-based dynamic water balance model to calculate crop water use over time, with a time step of one day. The model takes into account the daily soil water balance and climatic conditions for each grid cell. In addition, the water pollution associated with the use of nitrogen fertilizer in crop production is estimated for each grid cell. The crop evapotranspiration of additional 20 minor crops is calculated with the CROPWAT model. In addition, we have calculated the water footprint of more than two hundred derived crop products, including various flours, beverages, fibres and biofuels. We have used the water footprint assessment framework as in the guideline of the Water Footprint Network. Considering the water footprints of primary crops, we see that the global average water footprint per ton of crop increases from sugar crops (roughly 200 m3 ton−1), vegetables (300 m3 ton−1), roots and tubers (400 m3 ton−1), fruits (1000 m3 ton−1), cereals (1600 m3 ton−1), oil crops (2400 m3 ton−1) to pulses (4000 m3 ton−1). The water footprint varies, however, across different crops per crop category and per production region as well. Besides, if one considers the water footprint per kcal, the picture changes as well. When considered per ton of product, commodities with relatively large water footprints are: coffee, tea, cocoa, tobacco, spices, nuts, rubber and fibres. The analysis of water footprints of different biofuels shows that bio-ethanol has a lower water footprint (in m3 GJ−1) than biodiesel, which supports earlier analyses. The crop used matters significantly as well: the global average water footprint of bio-ethanol based on sugar beet amounts to 51 m3 GJ−1, while this is 121 m3 GJ−1 for maize. The global water footprint related to crop production in the period 1996–2005 was 7404 billion cubic meters per year (78 % green, 12 % blue, 10 % grey). A large total water footprint was calculated for wheat (1087 Gm3 yr−1), rice (992 Gm3 yr−1) and maize (770 Gm3 yr−1). Wheat and rice have the largest blue water footprints, together accounting for 45 % of the global blue water footprint. At country level, the total water footprint was largest for India (1047 Gm3 yr−1), China (967 Gm3 yr−1) and the USA (826 Gm3 yr−1). A relatively large total blue water footprint as a result of crop production is observed in the Indus river basin (117 Gm3 yr−1) and the Ganges river basin (108 Gm3 yr−1). The two basins together account for 25 % of the blue water footprint related to global crop production. Globally, rain-fed agriculture has a water footprint of 5173 Gm3 yr−1 (91 % green, 9 % grey); irrigated agriculture has a water footprint of 2230 Gm3 yr−1 (48 % green, 40 % blue, 12 % grey).


2018 ◽  
Author(s):  
Xiao-Bo Luan ◽  
Ya-Li Yin ◽  
Pu-Te Wu ◽  
Shi-Kun Sun ◽  
Yu-Bao Wang ◽  
...  

Abstract. Fresh water is consumed during agricultural production. With the shortage of water resources, assessing the water use efficiency is crucial to effectively managing agricultural water resources. The water footprint is a new index for water use evaluation, and it can reflect the quantity and types of water usage during crop growth. This study aims to establish a method for calculating the region-scale water footprint of crop production based on hydrological processes. This method analyzes the water-use process during the growth of crops, which includes irrigation, precipitation, underground water, evapotranspiration, and drainage, and it ensures a more credible evaluation of water use. As illustrated by the case of the Hetao irrigation district (HID), China, the water footprints of wheat, corn and sunflower were calculated using this method. The results show that canal water loss and evapotranspiration were responsible for most of the water consumption and accounted for 47.9 % and 41.8 % of the total consumption, respectively. The total water footprints of wheat, sunflower and corn were 1380–2888 m3/t, 942–1774 m3/t, and 2095–4855 m3/t, respectively, and the blue footprint accounts for more than 86 %. The spatial distribution pattern of the green, blue and total water footprint for the three crops demonstrated that higher values occurred in the eastern part of the HID, which had more precipitation and was further from the irrigating gate. This study offers a vital reference for improving the method used to calculate the crop water footprint.


2020 ◽  
Vol 12 (13) ◽  
pp. 5274 ◽  
Author(s):  
P.X.H. Bong ◽  
M.A. Malek ◽  
N.H. Mardi ◽  
Marlia M. Hanafiah

Modern technology and life-style advancements have increased the demand for clean water. Based on this trend it is expected that our water resources will be under stress leading to a high probability of scarcity. This study aims to evaluate the environmental impacts of selected traditional food manufacturing products namely: tempe, lemang, noodle laksam, fish crackers and salted fish in Malaysia. The cradle-to-gate approach on water footprint assessment (WFA) of these selected traditional food products was carried out using Water Footprint Network (WFN) and Life Cycle Assessment (LCA). Freshwater eutrophication (FEP), marine eutrophication (MEP), freshwater ecotoxicity (FETP), marine ecotoxicity (METP) and water consumption (WCP), LCA were investigated using ReCiPe 2016 methodology. Water footprint accounting of blue water footprint (WFblue), green water footprint (WFgreen) and grey water footprint (WFgrey) were established in this study. It was found that total water footprint for lemang production was highest at 3862.13 m3/ton. The lowest total water footprint was found to be fish cracker production at 135.88 m3/ton. Blue water scarcity (WSblue) and water pollution level (WPL) of these selected food products were also determined to identify the environmental hotspots. Results in this study showed that the WSblue and WPL of these selected food products did not exceed 1%, which is considered sustainable. Based on midpoint approach adopted in this study, the characterization factors for FEP, MEP, FETP, METP and WCP on these selected food products were evaluated. It is recommended that alternative ingredients or product processes be designed in order to produce more sustainable lemang.


2018 ◽  
Vol 22 (10) ◽  
pp. 5111-5123 ◽  
Author(s):  
Xiao-Bo Luan ◽  
Ya-Li Yin ◽  
Pu-Te Wu ◽  
Shi-Kun Sun ◽  
Yu-Bao Wang ◽  
...  

Abstract. Fresh water is consumed during agricultural production. With the shortage of water resources, assessing the water use efficiency is crucial to effectively manage agricultural water resources. The water footprint is an improved index for water use evaluation, and it can reflect the quantity and types of water usage during crop growth. This study aims to establish a method for calculating the regional-scale water footprint of crop production based on hydrological processes, and the water footprint is quantified in terms of blue and green water. This method analyses the water-use process during the growth of crops, which includes irrigation, precipitation, groundwater, evapotranspiration, and drainage, and it ensures a more credible evaluation of water use. As illustrated by the case of the Hetao irrigation district (HID), China, the water footprint of wheat, corn and sunflowers were calculated using this method. The results show that canal water loss and evapotranspiration were responsible for most of the water consumption and accounted for 47.9 % and 41.8 % of the total consumption, respectively. The total water footprint of wheat, corn and sunflowers were 1380–2888, 942–1774 and 2095–4855 m3 t−1, respectively, and the blue footprint accounts for more than 86 %. The spatial distribution pattern of the green, blue and total water footprints for the three crops demonstrated that higher values occurred in the eastern part of the HID, which had more precipitation and was further away from the irrigation gate. This study offers a vital reference for improving the method used to calculate the crop water footprint.


2014 ◽  
Vol 11 (1) ◽  
pp. 135-167 ◽  
Author(s):  
L. Zhuo ◽  
M. M. Mekonnen ◽  
A. Y. Hoekstra

Abstract. Water Footprint Assessment is a quickly growing field of research, but as yet little attention has been paid to the uncertainties involved. This study investigates the sensitivity of water footprint estimates to changes in important input variables and quantifies the size of uncertainty in water footprint estimates. The study focuses on the green (from rainfall) and blue (from irrigation) water footprint of producing maize, soybean, rice, and wheat in the Yellow River Basin in the period 1996–2005. A grid-based daily water balance model at a 5 by 5 arcmin resolution was applied to compute green and blue water footprints of the four crops in the Yellow River Basin in the period considered. The sensitivity and uncertainty analysis focused on the effects on water footprint estimates at basin level (in m3 t−1) of four key input variables: precipitation (PR), reference evapotranspiration (ET0), crop coefficient (Kc), and crop calendar. The one-at-a-time method was carried out to analyse the sensitivity of the water footprint of crops to fractional changes of individual input variables. Uncertainties in crop water footprint estimates were quantified through Monte Carlo simulations. The results show that the water footprint of crops is most sensitive to ET0 and Kc, followed by crop calendar and PR. Blue water footprints were more sensitive to input variability than green water footprints. The smaller the annual blue water footprint, the higher its sensitivity to changes in PR, ET0, and Kc. The uncertainties in the total water footprint of a crop due to combined uncertainties in climatic inputs (PR and ET0) were about ±20% (at 95% confidence interval). The effect of uncertainties in ET0 was dominant compared to that of precipitation. The uncertainties in the total water footprint of a crop as a result of combined key input uncertainties were on average ±26% (at 95% confidence level). The sensitivities and uncertainties differ across crop types, with highest sensitivities and uncertainties for soybean.


2021 ◽  
Vol 10 (6) ◽  
pp. e26610615777
Author(s):  
Ana Luiza Grateki Barbosa ◽  
Daniel Brasil Ferreira Pinto ◽  
Rafael Alvarenga Almeida

Currently, the management of water resources has gained greater visibility and has become indispensable, with the need for different methodologies which consider all water used and incorporated in the processes and products. In this way, the water footprint concept has been introduced to calculate the appropriation of fresh water on the part of the humankind. Thus, the objective of this work was to determine the water footprint in some sectors of family farming in the municipality of Teófilo Otoni – MG, analyzing the agricultural production of crops cultivated exclusively by the sector in 2017 in Teófilo Otoni. The cultivation of pumpkin, banana, chayote, beans, cassava, Maize, peppers, okra, cabbage, and tangerine were studied. Thus, the total water footprint for the year 2017 was 13,996,735.05 m3.t-1, in which the green water footprint represents 86%, the blue water footprint represents 12.5% and the gray water footprint equals 1.5%. The family farming sector of Teófilo Otoni demands an average of 196.73 liters for a production of R$ 1.00.


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