Ratio Of Water Use Research Articles

Soil Moisture Contribution to Winter Wheat Water Consumption from Different Soil Layers under Straw Returning

To study the contribution of moisture from different straw-treated and irrigated soil layers to the water consumption of winter wheat in dry farming, a 2-year straw treatment and regulated deficit irrigation experiment was implemented. The field experiment was carried out with 0% (S0), 1% (S1), and 2% (S2) straw returning amounts, and 75 mm (V3), 60 mm (V2), and 45 mm (V1) irrigation volumes. This experiment involved nine treatments, used to quantitatively analyze the ratio and variation of soil water use from different soil layers via the direct contrast method (DCM) and the multiple linear mixed model (MLMM). The results show the following: (1) The distribution of precipitation isotope compositions displayed a repeated trend of first decreasing and then increasing during the study period. Regression analysis showed that the local meteoric water line (LMWL): δD = 6.37δ18O − 3.77 (R2 = 0.832). (2) With increasing soil depth, the δ18O value decreased gradually, and the maximum δ18O value of the soil water within each growth period was distributed at 10 cm. (3) Under the same irrigation amount, δ 18O increased with increasing straw return at 0–20 cm and decreased with increasing straw return at 20–80 cm. (4) The comparison results of the DCM and MLMM were consistent. During the jointing and flowering stages, 0–30 cm soil water was the main source of water for winter wheat. The contribution of soil water below 30 cm had a decreasing trend from the jointing stage to the flowering stage. The average contribution rates of the 0–30 cm soil layer during the jointing and flowering stages were 23.07% and 23.15%, respectively. These findings have important implications for studying the soil water cycle in the context of farming.

Assessment and Factor Diagnosis of Water Resource Vulnerability in Arid Inland River Basin: A Case Study of Shule River Basin, China

Water resources in arid and semi-arid inland regions are highly vulnerable, facing threats from global climate change and human activities. Ensuring water resource sustainability requires scientifically evaluating the vulnerability of water resources and its driving factors. Taking the Shule River Basin, an inland river in northwest China, as an example, this study established an assessment system considering 16 influencing factors based on three aspects, including natural vulnerability, anthropogenic vulnerability, and carrying capacity vulnerability. The mature-element fuzzy model based on comprehensive weight and the Delphi method were used to evaluate the water resource vulnerability of the basin from 2005 to 2021. The results were as follows: (1) The water resource vulnerability in the Shule River Basin was between severe and moderate from 2005 to 2021, with a trend towards severe vulnerability. (2) The barrier analysis at the index level shows that factors of natural vulnerability had a low impact on water resource vulnerability in the basin from 2005 to 2019 but exerted a greater impact in 2020–2021, an impact that was far higher than that caused by factors of man-made vulnerability and water resource vulnerability. The impact of factors of anthropogenic vulnerability on water resource vulnerability was relatively low in the entire study period, except in 2016, 2017, 2020, and 2021. In 2005–2010, the factors of bearing capacity vulnerability had a great impact on water resource vulnerability, but in 2011–2021, the impact was alleviated and was gradually reduced. (3) Among the 16 factors affecting water resource vulnerability, the obstacle degree was higher than 6.5% for the following factors: the ratio of irrigation water use on farmland, the annual precipitation, total water resources, the annual quantity of wastewater effluent, the urbanization rate, the surface water control rate, and the degree of groundwater resource amount, exploration, and utilization obstacle values.

Global Assessment of Groundwater Stress Vis-à-Vis Sustainability of Irrigated Food Production

Due to poor water resources management, groundwater-dependent agriculture induces substantial stress on several aquifer systems worldwide, which poses a serious threat to water and food security. However, only a few studies have addressed this vital issue. This study aimed to evaluate stress on aquifers due to the overuse of groundwater for food production and explore pathways for stress reduction via improved irrigation efficiency and productivity. Groundwater stress was characterized using the ratio of water use to availability, with consideration for environmental flows. The results indicated that out of 107 countries—dependent on groundwater irrigation, about half are overexploiting groundwater, while one-fifth of these countries are extracting moderately-to heavily. Over 90% of the non-renewable groundwater abstraction occurs in 7 countries. Further, about 450 million tonnes (Mt) of global annual food production is from non-renewable groundwater exploitation. If the existing irrigation efficiency is increased to 90%, current groundwater stress would be reduced by 40%. Additionally, in unstressed regions, it would be possible to produce additional 300 Mt of food by using saved water while maintaining groundwater stress at acceptable levels. Moreover, improved water productivity in conjunction with increased irrigation efficiency could reduce the current level of unsustainable food production by 47%. These results provide important insights into the dynamics of irrigation stress on groundwater systems, and the role of managerial interventions.

Re-thinking water use in pig diets while accounting for food-feed competition

Livestock feed production is one of the primary users of freshwater and arable land, and it is also in competition with human food production. Therefore, we require reconsideration of the way we use freshwater in livestock feed production. The objective of this study is to assess the impact on freshwater use of pork production by using alternative pig diets based on local feed ingredients, or by-products. We used a lifecycle approach to analyse the freshwater use associated with feed production to produce one kg of pork. We explored three feeding scenarios (STANDARD: diets commercially used in Ireland; LOCAL: diets based on ingredients grown in Ireland; and BY-PRODUCT: diets based on by-products only). We calculated the freshwater use, using the water footprint (WFP) method, and the competition for water use between food and feed production using the water use ratio (WUR) for each scenario. The WUR quantifies the maximum amount of human digestible protein (HDP) derived from food crops that could be produced on the same land, and using the same water resources, that were used to grow the feed ingredients needed to produce 1 kg of pork.The WFP of the scenarios was 2,470 L/kg pork for STANDARD, 2,492 L/kg pork for LOCAL, and 2,205 L/kg pork for BY-PRODUCT. When we considered the WUR, none of the scenarios had a value < 1 (i.e. in all scenarios, more HDP can be produced from direct cultivation of food crops rather than pork). However, the BY-PRODUCT scenario (1.4) performed better than STANDARD (1.9) and LOCAL (2.9). Beet pulp and bakery by-products had zero WFP and no edibility and were thus considered promising ingredients. Moreover, rapeseed meal had a low WFP and rapeseed meal and sunflower seed meal are not considered human edible and were considered fit for future inclusion in diets. We also concluded that both the WFP and WUR methods have separate strengths and limitations, and should thus be used in conjunction; the ideal diet is one with the minimum WFP and WUR. Consideration of human edibility of feed ingredients is an important approach which should be included in future studies. Moreover, the entire food system including dairy, beef, poultry and other competitive uses should be taken into account when considering which feed ingredients to use in pig diets.

Aquifer vulnerability assessment for fecal coliform bacteria using multi-threshold logistic regression.

Assessing aquifer vulnerability is crucial for preventing groundwater pollution. In this study, aquifer vulnerability to fecal coliform (FC) pollution was assessed using auxiliary environmental data in the Pingtung Plain, Taiwan. Moreover, key environmental factors inducing different fecal pollution levels were determined. First, 23 explanatory variables on land uses, population density, livestock and poultry densities, sanitary condition, antecedent precipitation, groundwater quality, aquifer characteristics, and subsurface hydrology were obtained using geographic information systems in 2014. As dependent variables, groundwater FCs were also simultaneously obtained. Then, multi-threshold logistic regression (LR) was adopted to model aquifer vulnerability assessment after cross validation. The thresholds of aquifer vulnerability causing risks of incidental ingestion were analyzed by risk assessment. Risks to human health were acceptable for a low-level threshold and exceeded the acceptable level for medium- and high-level thresholds when residents incidentally ingested FC-polluted groundwater. Finally, key environmental factors inducing low, medium, and high levels of groundwater FC pollution were characterized. The key environmental factors for the LR with low- and medium-level thresholds were sand and gravel soil textures of unsaturated aquifers and antecedent 3-day cumulative precipitation, and those for the LR with high-level thresholds were chicken farming, urban land use, and ratio of tap water use. Thus, the multi-threshold LR indicated that environmental factors must be ranked for assessing aquifer vulnerability.

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

Africa is facing an increasing challenge with respect to water scarcity (WS), which is driven by climate change, population growth, and socioeconomic growth combined with inadequate water resources management. In particular, there is significant concern of virtual water (VW) trade, which plays the key role in water resource management and food security sustainability. Using bilateral trade data, this study consistently evaluated the change and balanced trade of major grains, the VW flows, WS status, water dependency (WD), water self-sufficiency (WSS), and water savings/losses within5 African sub-regions and their partners from 2000 to 2020. The ratio of water use to water availability was used to estimate the WS. The WD was quantified by the ratio of the net VW import to the regional water appropriation and the regional water savings/losses were also quantified by multiplying the inter-regional trade by the virtual water content of the imported/exported grains. The overall average trade deficit of African regions was found to increase to −1364.22 × 106 tons and Africa imported 41,359.07 Bm3 of VW from grain products. Green water contributed 79.33% of the total VWI. The WS values for East African countries were >100, indicating overexploitation. Besides, the overall WD in Africa was 465.5% for the studied period. The trade of main grains between Africa and the rest of the planet corresponded to a global water loss of 2820.7 Bm3·yr−1. However, the inter-continental cereal VW trade pattern and high trend will continue in the future. In view of the rising tension of WS, some African countries need to revise international crop trade and water resources conservation policies to promote a more balanced ecosystem. This study exemplifies that decision makers would consider VW flows and water savings/losses for enhancing water use efficiency and fair trading, thus increasing food production in Africa.

Simulating Biomass Production and Water Use of Poplars in a Plantation Using a STELLA-Based Model

Poplar trees (Populus spp.) are some of the fastest growing hardwoods used for biomass production. There are, however, conflicting observations about water use of poplars associated with the impact on local water resources. A STELLA (Structural Thinking and Experiential Learning Laboratory with Animation) model was modified to investigate the aboveground biomass production and water use in a mature (6 to 8 yrs. old) poplar plantation for a 3-year simulation period. The model predicted the typical annual pattern of soil evaporation, root water uptake, and leaf water transpiration in the poplar plantation increasing from winter to summer followed by respective decreases from summer to winter. Root water uptake and leaf water transpiration were proportional to the soil water content. More water was needed to produce the same amount of biomass during summer than during other seasons. Less water was consumed to produce the same amount of biomass as the age of the poplar trees increased. The net increase in biomass over the 3-year period was 0.69 × 104 kg/ha, which was equivalent to a 65% increase in biomass. The average rate of daily water use to daily biomass production was 1.05 × 109 cm3 water/kg biomass/ha. A good linear correlation between cumulative biomass production (CBP) and cumulative water use (CWU) was identified: YCBP = 0.001 ∗ XCWU, R2 = 0.99, p &lt; 0.001. This simple correlation provides a very good reference to estimate poplar water use efficiency (i.e., ratio of water use to biomass production) in growing regions where water resources are a limiting factor.

Покращення технології забору дренажних вод, які фільтруються з водосховищ, та їх використання

Goal. To offer the improved technology of water intake by systems of anti-filtration protection of territories against flooding from reservoirs and preparation of drainage waters for water use. Methods. Analytical-synthetic — for the analysis of modern scientific research and development of measures to improve the technology of water intake by anti-filtration curtains from flooding from reservoirs; statistical — for the analysis of parameters of a technological process; calculation — to create a simulation model of the anti-filtration curtain with vacuum siphon technology of water intake. Results. To improve the ecological condition of the territories located in the zones of influence of the Dnieper reservoirs, it is proposed to improve the design and technological parameters for vertical drainage systems. The main attention is paid to anti-filtration systems with airlift drainage from drainage wells, in particular the protection of the territory of Kamianskyi pod (area 6400 ha), located on the left bank of the Kakhovka reservoir. It is proposed to improve the anti-filtration systems by replacing the airlift technology of water intake from wells with a vacuum siphon to avoid clogging of the filters. According to the results of modeling according to the author’s method of calculation of vertical drainages with siphon drainage of filtration waters from wells, 3 different variants of anti-filtration curtains for hydrogeological conditions of Kamianskyi pod are presented. It is also proposed to use the drainage water, after proper preparation, to meet local water needs to avoid losses associated with its transportation over long distances. The ratio of daily human water use for sanitary, household, and drinking needs is considered. Conclusions. For rational water use, they proposed the use of groundwater, which causes flooding of areas adjacent to reservoirs, and pumped back to reservoirs, to use to meet different water needs. That is, use anti-filtration curtains as infiltration water intakes and return water after use and treatment to reservoirs.

Water resources efficiency assessment in crop production from the perspective of water footprint

Reducing water use and relieving negative environmental consequences contribute to regional water and ecological sustainability. This work examined water resource efficiency (WRE) and the effects of effective crop water use from the perspective of the water footprint. WRE was defined as the ratio of consumptive field water use (CWU) to the total crop water footprint (CWF), including the blue water footprint applied (BWFA), green water footprint (GWF), and grey water footprint (GYWF). WRE for the cultivation of the main crops (rice, wheat, maize, beans, and tubers) produced in China during the period of 1996–2015 was determined from estimates of provincial CWFs and CWUs. The results show that national CWF was estimated as 678.5 Gm³, of which GWF comprised 55.1%; the national crop CWU was approximately 455.6 Gm³ in the period considered, and this included 82.1% green and 17.9% blue water. The spatial patterns of CWF and CWU densities differed greatly but were stable over time, with increasing trends exhibited from 1996 to 2015. The national WRE for crops was 0.672, and that for beans was 0.869, an efficiency larger than that of any other crop. The indices for rice and wheat were approximately 0.630. WRE cannot be replaced by the global efficiency (GEF) or generalized efficiency (GE) indices, either for scientific evaluations or for considerations of spatial distributions. This study aids in the evaluation of effective water resource consumption by considering the process of agricultural water use, and also the impact of crop production on water quality and quantity. Hence, WRE is an advanced indicator linking measurements of water footprint with assessments of crop management and the sustainability of regional water resources.

Effective economic growth under conditions of regional water management dependence

Purpose. The purpose of the article is an identifying the impact of regional water management dependence on economic growth in the region.&#x0D; Methodology / approach. The subject of the study is theoretical and methodological basics of a new scientific paradigm for regulation the development of the regional socio-economic systems under the conditions of limited water resources. The study used traditional and special research methods, including: historical and logical – to analyze the evolution of regional socio-economic systems under conditions of limited water resources; abstractions and analogies – to reveal the essence of water-efficient regional socio-economic systems in the modern processes of regionalization and globalization; theoretical generalization, analysis and synthesis – to specify the categorical apparatus; statistical analysis to assess the level of needs of regional socio-economic systems in water resources and create an index of regional water management dependence; method of correlation analysis (biserial correlation, using a point biserial Pearson’s correlation coefficient).&#x0D; Results. The main idea of the paper is to study the issues of development of regional socio-economic systems under the conditions of limited water resources. Considering this, the paper is aimed at studying the impact of regional water management dependence on economic growth in the region. The tasks for development of regional socio-economic systems on the basis of water efficiency are defined, as well as the concept “water-efficient regional socio-economic system” is defined. The study presents a hypothesis about the need to change the paradigm of regulation of regional development on the basis of water use efficiency and regional water management dependence. In order to trade effectively with the main crops, it is necessary to determine whether there are sufficient water supplies in a given country and its regions. For this purpose, the authors proposes to use own indicator, such as the index of regional water management dependence. Thе characteristic of water management dependence is given, from regions where only up to half of the water supply of the territory is used, and to regions where more than 100 % of the water supply of the territory is used. The research has updated that the expansion of knowledge and understanding of the specifics of the water sector can solve significant problems. It is proved that the economic growth of the Ukrainian economy due to the agricultural sector has its limits and is limited by the water management dependence of the territories, ie the limitation of certain territories of the regions of Ukraine in terms of water resources. The next effective economic growth is possible only through the implementation of water-efficient technologies and intensification of water-efficient activities in the region.&#x0D; Originality / scientific novelty. The study for the first time defines the concept of water-efficient regional socio-economic system, so it is a socio-economic system that provides for the restoration of water resources in the region, reducing the water intensity of gross regional product (GRP) and approaching European norms and proposes the classification of regions according to the index of regional water management dependence on the basis of its threshold values. A scientific and methodological approach to assessing the level of needs of regional socio-economic systems in water resources has been improved, based on the application of the index of regional water management dependence, which is proposed to calculate the ratio of total fresh water use in the region to the volume of available river runoff in the region (parts of the water potential). The classification of regional socio-economic systems according to the level of water supply has been improved, which is based on the definition of threshold values of the index of regional water management dependence. The methodological bases for assessing the impact of the spatial economy on regional development under conditions of limited water resources have been improved, which differ in substantiating the dependence of the level of development of regions on the available water potential of the territory.&#x0D; Practical value / implications. The results of the study allow a more comprehensive approach to the study of the problem of using water resources in Ukraine in the context of their limitation. The results of the study showed that the economic complex in most regions is water-intensive and unbalanced, as well as does not provide restoration of water resources by environmental parameters and requires the implementation of infrastructure schemes for redistribution of water resources between regions for economic activity. The results are recommended for consideration by local governments and regional administration for the development and implementation of “Regional programs for the development of water management in the region” and for the development of “Strategies for regional development until 2025–2027”.

ESTIMATION OF CROP WATER REQUIREMENT AND CROP COEFFICIENT OF TOMATO CROP USING METEOROLOGICAL DATA IN PAMPAIDA MILLENNIUM VILLAGE, KADUNA STATE, NIGERIA

This report presents a study of crop water requirement and crop coefficient (Kc) for Tomato crop cultivated under irrigation in Pampaida Millennium Village Cluster, Ikara Local Government Area of Kaduna State, Nigeria, during the 2009/2010 dry season. A total of 7 tomato farmers were selected out of 45 farmers for the assessment exercise. Water applied per irrigation and soil moisture contents before and after irrigation was monitored throughout the seasons, while Tomato bulbs were harvested at the end of season and weighed. Average crop water use were estimated from the soil moisture content using the gypsum block, while daily reference Evapotranspiration (ETo) were computed from weather data using method Hargreaves equation. Crop coefficient values (Kc) were computed as the ratio of crop water use to ETo. The values of crop coefficients and seasonal crop water requirement per irrigation for different growth stages were determined, the computed *Kc values for different growth stage for the tomato crop grown in the study area was found to be between 0.77-1.15, the initial stage (*Kc =0.81; 20 mm/irrigation), crop development stage (*Kc = 1.09; 28 mm/irrigation), mid-season (*Kc = 1.15; 29 mm/ irrigation) and Late stage (*Kc = 0.77; 19 mm/irrigation), hence the mid-season gave the highest Kc value. However, the crop seasonal water requirement was found to be 386mm, which was within the recommended range. The crop coefficients and seasonal water requirement estimated in this study are reliable and could be used in irrigation design and scheduling for Tomato in the study area.

Influence of Crop Rotation and Soil Fertility Management Strategies on Water Use Efficiency of Wheat in a Changing Climate in Njoro Sub-County in Kenya

Aims: The study determined the effect of soil fertility management (inorganic and organic N sources) and short term crop rotation (cereal – legumes cropping systems) on water use efficiency of wheat in high potential areas.&#x0D; Study Design: A randomized complete block design was used with split-split-plot arrangement replicated three times. Three factors evaluated included water harvesting (WH), crop rotation (CR) and soil fertility management (SFM). The data obtained were subjected to an analysis of variance (ANOVA) using Genstat statistical package while the mean separation was performed using least significance differences (P =.05).&#x0D; Place and Duration of Study: The trial was conducted at the Kenya Agricultural and Livestock Research Organization (KALRO) fields based in Njoro for three years between 2014 and 2016 during rainy seasons.&#x0D; Methodology: Water harvesting was evaluated at consisted of flat beds (WH1) and tied ridges (WH2), crop rotation was tested at four levels comprising of Wheat- Dolichos lablab (Lablab purpureum)-Wheat- L. purpureum (CR1); Wheat-Greenpea (P. sativum) –Wheat (Triticum aestivum L)- P. sativum (CR2); T. aestivum L-potato- P. sativum –Potato (Solanum tuberosum) (CR3); and Wheat-Wheat-Wheat-Wheat) (CR4). Six different soil fertility management (SFM) strategies evaluated included SFM1 = untreated control; SFM2 = Farm Yard Manure at 5 t ha-1; SFM3 = Green manure (L.eucaena triachandra) at 2.5 mt ha-1; SFM4 = Calcium Ammonium Nitrate (CAN) at 25 kg N ha-1; SFM5 = Calcuim Ammonium Nitrate at 50 kg N ha-1; and SFM6 = Ammonium Nitrate (CAN) at 75 kg N ha-1. The Water harvesting (WH) and SFM were fixed on the same plot at the form and rate for the entire period of the study while crops were rotated between seasons. Water use efficiency was derived as a ratio of water use and grain yield and biomass.&#x0D; Results: Results revealed significant (P =.05) effect of crop rotation and soil fertility management on water use efficiency. However, water harvesting did not influence. While interaction of CR and SFM significantly (P =.05) influenced WUE and grain yield. Significant influence was also observed on WUE due to an interaction between WH and SFM. Dolichos lablab (L. purpureum) and green pea as pre-crops resulted in higher yield than when potato was the pre-crop and continuous wheat. Use of inorganic N fertilizer with L. purpureum as a pre-crop resulted in higher grain yield than all other soil fertility management strategies evaluated. In conclusion, the use of green pea as a pre-crop during the short rain followed by wheat in long rains is a beneficial crop rotation systems and a climate smart strategy. In addition, organic N sources should be recommended for sustainable wheat production because it will positively influence the accumulation and slow release of soil moisture for increased water use efficiency.

Investigation into sustainable water use in India using combined large-scale earth system-based modelling and census-based statistical data

Sustainable water use and water scarcity are major concerns in developing countries such as India. Rapidly growing population along with increasing economic and technological development in India have resulted in increased water use leading to severe water scarcity. The present study aims to quantify and assess sustainable water use and water scarcity in India. A data-intensive approach is employed at a State spatial resolution and monthly temporal scales during the period 1991–1999. The Water Stress Index (WSI), which is defined as the ratio of total water use to available water, is used as a measure of blue water scarcity. The total available water includes surface water and groundwater while the total water uses include irrigation, industrial, domestic and environmental uses. A Community Land Model (CLM 4.0) developed by the National Centre for Atmospheric Research (NCAR), is used to quantify the total available water in India. Water uses in India are reconstructed using a census-based statistical database while the environmental water demand is modelled following the hydrology-based approach, which allocates environmental flows as a proportion of the available water, with seasonally defined environmental flow thresholds. Further, the excess water component, defined as the amount of water remaining after meeting the demands at each time step, is incorporated into the modelling framework by adding it to the available water pool. The study estimates that 60% of the population in India faces severe water stress during the analysis period, and is more predominant in the States of Rajasthan, Gujarat, Uttar Pradesh and Maharashtra. Moreover, non-renewable groundwater abstraction, which is defined as the amount of groundwater abstraction more than the groundwater recharge, is also quantified. This study identifies severe groundwater depletion in the north-western parts of India, consistent with the current estimates from GRACE satellite observations.

Severe drought strongly reduces water use and its recovery ability of mature Mongolian Scots pine (Pinus sylvestris var. mongolica Litv.) in a semi-arid sandy environment of northern China

Trees growing in a semi-arid sandy environment are often exposed to drought conditions due to seasonal variations in precipitation, low soil water retention and deep groundwater level. However, adaptability and plasticity of individuals to the changing drought conditions greatly vary among tree species. In this study, we estimated water use (Ts) of Mongolian Scots pine (MSP; Pinus sylvestris var. mongolica Litv.) based on sap flux density measurements over four successive years (2013–2016) that exhibited significant fluctuations in precipitation in a semi-arid sandy environment of northern China. The results showed that fluctuations in daily Ts synchronously varied with dry-wet cycles of soil moisture over the study period. The daily ratio of water use to reference evapotranspiration (Ts/ET0) on sunny days in each year showed a negative linear relationship with the severity of drought in the upper soil layer (0–1 m; P<0.01). The decrease in Ts induced by erratic drought during the growing season recovered due to precipitation. However, this recovery ability failed under prolonged and severe droughts. The Ts/ET0 ratio significantly declined with the progressive reduction in the groundwater level (gw) over the study period (P<0.01). We concluded that the upper soil layer contributed the most to the Ts of MSP during the growing season. The severity and duration of droughts in this layer greatly reduced Ts. Nevertheless, gw determined whether the Ts could completely recover after the alleviation of long-term soil drought. These results provide practical information for optimizing MSP management to stop ongoing degradation in the semi-arid sandy environments.

Reconstructed natural runoff helps to quantify the relationship between upstream water use and downstream water scarcity in China's river basins

Abstract. The increasing conflicts for water resources between upstream and downstream regions appeal to chronological insight across the world. While the negative consequence of downstream water scarcity has been widely analyzed, the quantification of influence of upstream water use on downstream water scarcity has received little attention. Here non-anthropologically intervened runoff (natural runoff) was first reconstructed in upstream, middle stream and downstream regions in China's 12 large basins in the 1970s to 2000s time period using the Fu–Budyko framework, and then compared to the observed data to obtain the developmental trajectories of water scarcity, including the ratio of water use to availability (WTA) and the per capita water availability (FI; Falkenmark Index) on a decadal scale. Furthermore, a contribution analysis was used to investigate the main drivers of water scarcity trajectories in those basins. The results show that China as a whole has experienced a rapid increase of WTA stress with surface water use rapidly increasing from 161 billion cubic meters (12 % of natural runoff) in the 1970s to 256 billion cubic meters (18 %) in the 2000s, with approximately 65 % increase occurring in northern China. In the 2000s, the increase of upstream WTA stress and the decrease of downstream WTA stress occurred simultaneously for semi-arid and arid basins, which was caused by the increasing upstream water use and the consequent decreasing surface water use in downstream regions. The influence of upstream surface water use on downstream water scarcity was less than 10 % in both WTA and FI for humid and semi-humid basins during the study period, but with an average of 26 % in WTA and 32 % in FI for semi-arid and arid basins. The ratio increased from 10 % in the 1970s to 37 % in the 2000s for WTA and from 22 % in the 1980s to 37 % in the 2000s for FI. The contribution analysis shows that the WTA contribution greatly increases in the 2000s mainly in humid and semi-humid basins, while it decreases mainly in semi-arid and arid basins. The trajectories of China's water scarcity are closely related to socioeconomic development and water policy changes, which provide valuable lessons and experiences for global water resources management.

China's provincial grey water footprint characteristic and driving forces

Grey water footprint (GWF), as a measure of water pollution in terms of the amount of water needed to dilute pollutants, has drawn great attention due to the necessity to respond to water contamination and water scarcity challenges. Under such a circumstance, this study aims to reveal China's national and provincial GWF features from 2003 to 2015, and to identify the corresponding driving forces by using the Kaya equation and the Logarithmic Mean Division Index (LMDI) decomposition method. Results show that the national total GWF declined from 1418 billion m3 in 2003 to 1655 billion m3 in 2015, and the industrial GWF reduction was the main reason for this decrease. Domestic GWF was the dominant component, particularly for service dominated provinces such as Beijing, Shanghai, Hainan, etc., with proportion up to about 80%. Southern and eastern provinces had higher GWF but lower GWF intensity (GWF per unit GDP), and water scarce northern provinces exhibited higher GWF load although they had lower GWF. The GWF intensity experienced a decreasing trend, with economy effect and intensity effect being the main driving forces, particularly for Tibet. Technology effect and exploitation effect (ratio of water use to water resource) were the main barriers for less developed provinces. Finally, policy recommendations are proposed to alleviate future GWF challenges of China, such as improving the discharge standards of WWTP (wastewater treatment plant), promoting wastewater recycling, reducing GWF intensity and GWF load through industrial structure and trade structure adjustment.

Cross-Sectoral Analysis of Water Usage in Thailand Using Input–Output Model

Thailand currently ranks third among the most water-intensive countries in the world. The percentage shares of water demand in the country’s agriculture, manufacturing, and service sectors, which are major economic sectors, are 75%, 3%, and 5%, respectively. With the continuous growth of the economy, the demand for water is steadily rising, while the expansion of water supply remains constrained by several factors and the water supply is also affected by climate change. This study uses the input–output model to examine the relationship between water usage and the economic system in Thailand in 2010. The constructed input–output model is the integration of the Leontief inverse matrix, the matrix of water usage, and the details of the gross domestic product (GDP). The model indicates the linkage between GDP expansion and water demand in both direct and indirect usage. The computation result obtained from the model indicates that the agricultural sector is the major water user, with its ratio of direct water use being the highest. The manufacturing sector records the highest ratio of indirect water use, which is influenced by its supply chain comprising the agriculture and service sectors. This model and its results may serve as the main foundation for the design of economic and environmental policies oriented toward optimizing water demand and supply. The model can also be extended and enriched with detailed mechanisms of economic behavior to allow further complex analyses such as water pricing policies.

Freshwater use in livestock production—To be used for food crops or livestock feed?

Current approaches to estimate freshwater use in livestock production systems generally fail to consider the competition for water resources with alternative uses, such as production of food crops food or other ecosystem services. This article presents a new method to account for the competition for freshwater use between food crops and animal feed, while assessing freshwater use in livestock production systems. The developed water use ratio (WUR) is defined as the maximum amount of human digestible protein (HDP) derived from food crops from the consumptive water use (CWU) appropriated to produce 1kg of animal-source food (ASF) over the amount of HDP in that 1kg of ASF. The CWU for livestock production is first categorized according to the land over which it is consumed, based on the suitability of that land to produce food crops. Then, the method assesses food-feed competition by determining the amount of HDP that could have been produced from food crops, using the same CWU currently used to produce ASF. The method enables identification of livestock production systems that contribute to global food supply without competing significantly over water resources with food production, based on their CWU. Three beef production systems in Uruguay are used to illustrate the method. During the backgrounding and the finishing stages, which are analyzed in this study, cattle can be kept on natural pasture (NP), seeded pasture (SP) or in feedlots (FL). The following three systems were analysed: i) NP-NP, ii) SP-SP and iii) SP-FL. Results show that the NP-NP system uses the largest amount of water per kg of beef output. However, results also show that the SP-SP and SP-FL systems can potentially produce more HDP by growing food crops than by producing beef. Based on the traditional measure for water productivity, i.e. the quantity of CWU per kilo of beef produced, we would conclude that the NP-NP system is least efficient, whereas based on the WUR the NP-NP system is the only system producing HDP more efficiently than food crops. Sustainable intensification not only implies improving agriculture and livestock productivity per unit of resource used, but also improving the number of human beings nourished. Results from this study illustrate the importance of considering competition and trade-offs with other uses when evaluating water use efficiency of livestock systems to promote sustainable intensification.

The Analysis of Water Footprint of Production and Water Stress in China

Abstract: Water footprint of production can be used to identify pressure on national or regional water resources generated by production activities. Water stress is defined as the ratio of water use (the difference between a regional water footprint of production and a green water footprint) to renewable water resources available in a country or region. Water stress can be used to identify pressure on national or regional water resources generated by production activities. This paper estimates the water footprint of production and the water stress in China during the years 1985–2009. The result shows that China's water footprint of production increased from 781.58 × 109 m3 in 1985 to 1109.76 × 109 m3 in 2009. Mega-cities and regions with less agriculture production due to local climatic conditions (Tibet and Qinghai) had lower water footprint of production, while the provinces (Henan, Shandong) with higher agriculture production had higher footprint. Provinces with severe water stress increased from 6 in ...

Growth and Water Use During Establishment of Irrigated Bare Root and Balled-Burlap Green Ash Transplanted Into A High Desert Landscape

We investigated growth, water relations, and water use of bare root (BR) and balled-burlapped (BB) Patmore green ash following transplanting into an irrigated landscape setting in a high desert climate. Treatments were green ash harvested as larger (40 mm caliper) BB and BR trees, and smaller BR stock (25 mm caliper). During establishment, we measured canopy growth for 3 years, and for 2 years plant water relations [predawn water potential and midday stomatal conductance (gS)] and water depletion within the root zone. All treatments expressed varying degrees of isohydric responses to root loss by reducing gS that maintained water potential nearly constant, but least so for the smaller BR trees. gS was greater than that of all larger trees, meaning that for the same cost in water potential as the larger trees, BR-Small benefitted from more open stomates and presumably greater carbon gain. Greater initial conductance apparently translated into more growth. Year 1, BR-Small trees had the least total leaf area, but by Year 3 total leaf area was not different among all treatments. Also during Year 1, the ratio of water use to local reference evapotranspiration [plant factor (PF)] was 0.36 for large BR trees vs. 0.56 for BB trees, similar to the recommended PF of 0.5 for trees in dry climates. These results suggest smaller BR trees are a cheaper alternative for high desert landscapes while reaching nearly equivalent growth to BB trees after 3 years. Achieving high growth of BR trees would need careful scheduling of irrigation amount and frequency based on leaf area, root zone size, and local reference evapotranspiration.