Total Water Supply Research Articles

Comparative Effectiveness of Reservoir Operation Applying Hedging Rules Based on Available Water and Beginning Storage to Cope with Droughts

The discrete hedging rule which runs through several hedging phases can be an effective method for water supply operation from a reservoir during drought periods. This paper aims to derive two different hedging rule curves of a reservoir: one rule is based on available water that accompanies prediction of the current period inflow and the other rule is based on the beginning storage alone. The current period inflow was obtained by the ensemble streamflow prediction using historical precipitation data. A mixed integer programming algorithm was used to determine hedging rule curves for water supply operation of Hapcheon dam, the Republic of Korea for the period from 1990 to 2005 that included a drought period. Complying with the derived hedging rules, reservoir simulation runs for the period from 2006 to 2010 were performed. The derived hedging rule curves based on the beginning storage were placed higher than the curves based on available water and induced earlier rationing of water supply. The rule based on available water included the current period inflow and its simulation resulted in faster recovery to the normal phase of water supply when the drought ended. The simulation results applying the rule based on available water were 25% better in terms of the total water supply deficit and reliability; they, however, were 5% worse on the vulnerability. When predicted inflow is not reliable, the hedging rule based on the beginning storage might be worth in practical reservoir operation to avoid severer shortage resulted from the bad prediction of the inflow.

Downside risk in reservoir management

Downside risk, which refers to deviations below a threshold, is often important in water management decisions, especially in areas with large and skewed variations in precipitation patterns. In this paper, we present a model for a reservoir manager who is downside risk averse and who performs a dynamic allocation of irrigation water, taking into account the negative effects of droughts on farm profits and different environmental constraints. We analyse the water stock, flows and agricultural profits for alternative environmental restrictions and thresholds for irrigation levels and find that stricter environmental constraints increase total water supply and carryover stock, while higher penalty thresholds lead to their overall decrease. Furthermore, increasing penalty thresholds leads to a higher emphasis on avoiding shortages, at the expense of lower average profits.

Hygienic characteristics of the chemical composition of groundwater in Ryazan region

Among the factors that have a strong impact on public health the environment, living conditions, food and water quality are just as important as socio-economic forces. Providing the population with access to safe potable water has become a socio-economic priority in Russia. The aim of this work was to characterize the aquifers supplying the population of Ryazan region with water for personal and domestic needs and to compare their chemical composition. Sample collection was performed in cooperation with the Center for Hygiene and Epidemiology (Ryazan region). The obtained data were processed using ANOVA. The Kashirsky and Ozersko-Khovansky aquifers turn to be the most commonly used ones supplying water to 30.7% and 27.3% of the total artesian wells. The Oksko-Tarussky and Podolsko-Myachkovsky aquifers rank second, feeding 21% and 18.9% of the wells, respectively. The share of the Kasimovsky aquifer in the total water supply is only 2.1%. Although the recommended lifespan of an artesian well is 25 years, two-thirds of the wells in Ryazan region have been in service for 26 to 50 years, and one in every 4 wells is over 50 years old. The chemical composition of the groundwater drawn from different aquifers is different. High concentrations (0.7 mg/l) of iron (Fe2+) are present in the water from the Ozersko-Khovansky aquifer (р ≥ 0.05). Sulfates are found in abundance in the Podolsko-Myachkovsky and Ozersko-Khovansky aquifer. The water from the Oksko-Tarussky aquifer contains high concentrations of ionized ammonia.

Quantification of water and sewage leakages from urban infrastructure into a shallow aquifer in East Ukraine

Leaky water supply and sewer mains can become unmanaged sources of urban groundwater recharge and contamination posing environmental and health risks. Stable isotopes of water and hydrochemical tracer were applied to quantify water and sewage leakages in a shallow aquifer of a large Ukrainian city. Binary and ternary mixing models were used based on the d-excess and chloride concentrations of tap water, rural and urban groundwater to estimate fractions of natural recharge, urban seepage, volumes of water supply and sewage leakages in urban springs. Water supply leakages that recharge aquifer were ~ 3% (6.5 Mm3 a− 1) of the total water supply and strongly correlated with failures on the water infrastructure. Sewage leakages (1.4 Mm3 a− 1) to the aquifer were less in amount than water supply leakages, but induced nitrate and associated contaminants pollution risk of urban groundwater. The proposed method is useful for the pilot evaluation of urban groundwater recharge and contamination and can be applied in other regions worldwide to support the decision-making in water management.

Nitrogen species distribution in groundwater of the Haihe River Plain

Abstract Natural and anthropogenic nitrate (NO3-N), nitrite (NO2-N) and ammonia (NH4-N) in groundwater represents vital environmental and health concern issue globally. Here, we present data and discuss sources of nitrogen compounds in the groundwater that accounts for two-thirds of the total water supply of the Haihe River Plain with a population of over 100 million. The spatial and temporal distribution of the nitrogen compounds (NO3-N, NO2-N, NH4-N) in the groundwater are linked to a variety of sources, such as fertilizers, domestic sewages, industrial wastewater and precipitation. About 12.64%, 53.90% and 16.73% of the investigated groundwater wells in the Haihe River Plain have NO3-N, NO2-N and NH4-N concentrations above permissible values for drinking water, respectively. Comprehensive actions such as changing farming methods, applying fertilizer at suitable times and appropriate irrigation pattern for the Haihe River Plain are required to reduce the nitrogen pollution in the future.

Water use for shale gas extraction in the Sichuan Basin, China

This study investigates the use of water for extracting shale gas in the Sichuan Basin of China. Both net water use and water intensity (i.e., water use per unit of gas produced) of shale wells are estimated by applying a process-based life cycle inventory (LCI) model. The results show that the net water use and water intensity are around 24500 m3/well and 1.9 m3 water/104 m3 gas respectively, and that the fracturing and completion stage of shale gas extraction accounts for the largest share in net water use. A comparison shows that China's water use for shale gas extraction is generally higher than that of other countries. By considering the predicted annual drilling activities in the Sichuan Basin, we find that the annual water demand for shale gas development is likely to be negligible compared to total regional water supply. However, considering the water demand for shale gas extraction and the water demand from other sectors may make water availability a significant concern for China's shale gas development in the future.

A WATER AUDIT ANALYSIS TOOL FOR URBAN WATER UTILITY

This paper introduces a procedure for calculating non revenue water (NRW) based on IWA terminology. A water audit analysis tool is developed to determine the components of water balance i.e.; apparent and real losses for Jaipur water utility, India. Identification of these parameters is important especially in developing countries with critical water resource situation in water scare urban area. Water audit analysis tool also evaluates the leakage performance indicators i.e. Unavoidable Real Losses (UARL) and Infrastructure Leakage Index (ILI). Results reveals that Jaipur water utility suffers with a technical and managerial constraints and reporting high level of non revenue water (50% of the total water produced). The Real losses (37% of total water supplied) is the major component of NRW due to old deteriorating water supply asset with poor operation and management (O&M). Apparent losses (8% of the total water supplies) are significant component of NRW due to meter under registration, illegal connections and thefts and also indicated by value of Infrastructure Leakage Index (2.311). There is need of proper NRW reduction strategy which addresses all these three issues of real losses, unauthorized consumption and management practices along with change management strategy.

Analysis of Annual Water Use Time-series and Influencing Factors in China

Water resources are one of the most precious resources on the earth. Faced with the increasingly severe shortage of water, human awareness of water conservation is constantly increasing. This paper analyzes the time series of annual average water consumption in China from 2004 to 2016 and the influencing factors for 13 years. It is concluded that China’s per capital water consumption is mainly affected by total water supply, total surface water supply, total ground water supply, total agricultural water supply and total industrial water supply, and the influence of these five factors are all positive, however, it is worth noting that the real factor affecting China’s per capital water consumption is the total amount of water used for agriculture and industry, which has nothing to do with the total amount of domestic water.

A WATER AUDIT ANALYSIS TOOL FOR URBAN WATER UTILITY

This paper introduces a procedure for calculating non revenue water (NRW) based on IWA terminology. A water audit analysis tool is developed to determine the components of water balance i.e.; apparent and real losses for Jaipur water utility, India. Identification of these parameters is important especially in developing countries with critical water resource situation in water scare urban area. Water audit analysis tool also evaluates the leakage performance indicators i.e. Unavoidable Real Losses (UARL) and Infrastructure Leakage Index (ILI). Results reveals that Jaipur water utility suffers with a technical and managerial constraints and reporting high level of non revenue water (50% of the total water produced). The Real losses (37% of total water supplied) is the major component of NRW due to old deteriorating water supply asset with poor operation and management (O&M). Apparent losses (8% of the total water supplies) are significant component of NRW due to meter under registration, illegal connections and thefts and also indicated by value of Infrastructure Leakage Index (2.311). There is need of proper NRW reduction strategy which addresses all these three issues of real losses, unauthorized consumption and management practices along with change management strategy.

Long-Term Winter Wheat (Triticum aestivum L.) Seasonal Irrigation Amount, Evapotranspiration, Yield, and Water Productivity under Semiarid Climate

A long-term field experiment was conducted from 2002 to 2014 for the evaluation of yield and water productivity of three winter wheat varieties—Kharkof, Scout 66, and TAM107—under sprinkler irrigation at New Mexico State University Agricultural Science Center at Farmington, NM. Winter wheat daily evapotranspiration was estimated following the United Nations Food and Agriculture Organization FAO crop coefficient approach (ETc = Kc ETo), and crop water use efficiency (CWUE), evapotranspiration water use efficiency (ETWUE), and irrigation water use efficiency (IWUE) were estimated for each growing season. There was inter-annual variation in seasonal precipitation and irrigation amounts. Seasonal irrigation amounts varied from 511 to 787 mm and the total water supply varied from 590 to 894 mm with precipitation representing a range of 7.7–24.2%. Winter wheat daily actual evapotranspiration (ETc) varied from 0.1 to 14.5 mm/day, averaging 2.7 mm/day during the winter wheat growing seasons, and the seasonal evapotranspiration varied from 625 to 890 mm. Grain yield was dependent on winter wheat variety, decreased with years, and varied from 1843.1 to 7085.7 kg/ha. TAM107 obtained the highest grain yield. Winter wheat CWUE, IWUE, and ETWUE were also varietal dependent and varied from 0.22 to 1.01 kg/m3, from 0.26 to 1.17 kg/m3, and from 0.29 to 0.92 kg/m3, respectively. CWUE linearly decreased with seasonal water, and IWUE linearly decreased with seasonal irrigation amount, while CWUE, IWUE, and ETWUE were positively correlated with the grain yield for the three winter wheat varieties, with R2 ≥ 0.85 for CWUE, R2 ≥ 0.69 for IWUE, and R2 ≥ 0.89 for ETWUE. The results of this study can serve as guidelines for winter wheat production in the semiarid Four Corners regions. Additional research need to be conducted for optimizing winter wheat irrigation management relative to planting date and fertilization management to reduce the yield gap between winter wheat actual yield and the national average yield.

Experimental Study of Optimum Chilled Water Distribution Configuration in Air Conditioning Terminal Unit Using RSM Technique

The distribution of chilled water flow rate in terminal unit is an important factor used to evaluate the performance of central air conditioning unit. A prototype of A/C unit has been made, which contains three terminal units with a complete set of accessories (3-way valve, 2-way valve, and sensors) to study the effect of the main parameters, such as total water flow rate and chilled water supply temperature with variable valve opening. In this work, 40 tests were carried out. These tests were in two groups, 20 test for 3-way valve case and 20 test for 2-way valve case. These tests were performed at three levels of valve opening, total water flow rate and water supply temperature according to the design matrices established by Design of Experiment (DOE) software 'version 7' with Response surface methodology (RSM) technique. The model was conducted for each case of total heat rate, then checked statistically for adequacy by Analysis of variance (ANOVA), and found good with 95% confidence level. The results showed that the water supply temperature has a significant effect on the total heat rate of two cases. It was found that the optimum solution for maximum total heat rate and minimum flow deviation represented by standard deviation was obtained at 10°C water supply temperature, 5.5 l/min total water flow rate and 70% valve opening. The total heat rate and standard deviation were (890.249 Watt), (0.000513), respectively in three-way valve case and (743.155 Watt), (0.00277), respectively in two-way valve case. Finally, the predicted and experimental results of total heat rate and standard deviation were in agreement with a maximum error of 6.6 % in three-way valve case and 1.4% in two-way valve case.

A Simulation-Based Linear Fractional Programming Model for Adaptable Water Allocation Planning in the Main Stream of the Songhua River Basin, China

The potential influence of natural variations in a climate system on global warming can change the hydrological cycle and threaten current strategies of water management. A simulation-based linear fractional programming (SLFP) model, which integrates a runoff simulation model (RSM) into a linear fractional programming (LFP) framework, is developed for optimal water resource planning. The SLFP model has multiple objectives such as benefit maximization and water supply minimization, balancing water conflicts among various water demand sectors, and addressing complexities of water resource allocation system. Lingo and Excel programming solutions were used to solve the model. Water resources in the main stream basin of the Songhua River are allocated for 4 water demand sectors in 8 regions during two planning periods under different scenarios. Results show that the increase or decrease of water supply to the domestic sector is related to the change in population density at different regions in different target years. In 2030, the water allocation in the industrial sector decreased by 1.03–3.52% compared with that in 2020, while the water allocation in the environmental sector increased by 0.12–1.29%. Agricultural water supply accounts for 54.79–77.68% of total water supply in different regions. These changes in water resource allocation for various sectors were affected by different scenarios in 2020; however, water resource allocation for each sector was relatively stable under different scenarios in 2030. These results suggest that the developed SLFP model can help to improve the adjustment of water use structure and water utilization efficiency.

Soybean crop-water production functions in a humid region across years and soils determined with APEX model

Crop production as a function of water use or water applied, called the crop water production function (CWPF), is a useful tool for irrigation planning, design and management. However, these functions are not only crop and variety specific they also vary with soil types and climatic conditions (locations). Derivation of multi-year average CWPFs through field experiments for different locations and soils is time-consuming and expensive, as it requires careful long-term and multi-location field experiments to obtain them. Process based crop system models provide a useful tool for determining CWPFs using short-term field experimental data for calibration and validation. The aim of this study was to determine soybean CWPFs using the Agricultural Policy/Environmental eXtender (APEX) model across three soil types (Vaiden-silty clay, Cahaba-sandy loam, and Demopolis-clay loam) and three weather conditions (14-year average from 2002 to 2015, dry, and wet) of a humid irrigated region in Mississippi, USA. The results showed that the relationship between simulated soybean grain yield (GY) and the seasonal crop evapotranspiration (ET) for each soil under 14-year average weather condition was linear. Compared with the Vaiden soil, the Cahaba and Demopolis soils had slightly higher water use efficiency (WUE) over 14-year average weather conditions. The CWPFs for GY vs supplemental irrigation were cubic polynomials for all soil types and weather conditions, with varying coefficients. The maximum values of irrigation water use efficiency (IWUEmax) derived from these cubic CWPFs varied from 2.58 to 9.89 kg ha−1 mm−1 across soils and weather conditions. The irrigation amount during the growing season required (Imax) to achieve the maximum GY for soybean also had a wide range of values, from 110 to 405 mm. The IWUE and Imax were related to available water holding capacity of soils. The relationship between GY and total plant available water supply (TWS) was also a cubic function, with coefficients varying with soil types and climatic conditions. The yield response factor (Ky) was 1.24 (greater than 1.00) when averaged over 14 years’ weather data, indicating that soybean was very sensitive to water stress even in a humid region like Mississippi. Thus, supplemental irrigation is necessary to increase GY and ensure stability in yields.

Planning for Regional Water System Sustainability Through Water Resources Security Assessment Under Uncertainties

A leader-follower relationship in multiple layers of decision makers under uncertainties is a critical challenge associated with water resources security (WRS). To address this problem, a credibility-based chance-constrained hierarchical programming model with WRS assessment is developed for regional water system sustainability planning. This model can deal with the sequential decision-making problem with different goals and preferences, and reflect uncertainties presented as fuzzy sets. The effectiveness of the developed model is demonstrated through a real-world water resources management system in Beijing, China. A leader-follower interactive solution algorithm based on satisfactory degree is utilized to improve computational efficiency. Results show the that: (a) surface water, groundwater, recycled water, and off water would account for 27.01, 27.44, 23.11, and 22.44% of the total water supplies, respectively; (b) the entire pollutant emissions and economic benefits would consequently decrease by 31.53 and 22.88% when the statue changes from quite safe to extremely far from safe; and (c) a high credibility level would correspond to low risks of insufficient water supply and overloaded pollutant emissions, which lowers economic benefits and pollutant emissions. By contrast, a low credibility level would decrease the limitations of constraints, which leads to high economic benefits and pollutant emissions, but system risk would be increased. These findings can aid different decision makers in identifying the desired strategies for regional water resources management under multiple uncertainties, and support the in-depth analysis of the interrelationships among water security, system efficiency, and credibility level.

Crop Evapotranspiration, Irrigation Water Requirement and Water Productivity of Maize from Meteorological Data under Semiarid Climate

Under the semiarid climate of the Southwest United States, accurate estimation of crop water use is important for water management and planning under conservation agriculture. The objectives of this study were to estimate maize water use and water productivity in the Four Corners region of New Mexico. Maize was grown under full irrigation during the 2011, 2012, 2013, 2014 and 2017 seasons at the Agricultural Science Center at Farmington (NM). Seasonal amounts of applied irrigation varied from 576.6 to 1051.6 mm and averaged 837.7 mm and the total water supply varied from 693.4 to 1140.5 mm. Maize actual evapotranspiration was estimated using locally developed crop coefficient curve and the tabulated United Nations Food and Agriculture Organization (FAO) crop coefficients, and from this maize water productivity was determined. Maize actual daily evapotranspiration (ETa) varied from 0.23 to 10.2 mm and the seasonal ETa varied with year and ranged from 634.2 to 697.7 mm averaging 665.3 mm by the local Kc curve, from 687.3 to 739.3 mm averaging 717.8 mm by the non-adjusted FAO Kc values, and from 715.8 to 779.6 mm averaging 754.9 mm with the FAO adjusted Kc values. Maize irrigation requirements varied from 758.4 to 848.3 mm and averaged 800.2 mm using the local developed Kc and varied from 835.5 to 935.6 mm and averaged 912.2 mm using FAO Kc. The net irrigation requirement varied from 606.8 to 678.6 using local Kc curve, and from 682.78 to 748.5 mm when adopting the FAO Kc values. Average irrigation requirement was 641 mm under the local Kc option and 730 mm under FAO Kc values option. Maize crop water use efficiency (CWUE) ranged from 1.3 to 1.9 kg/m3 and averaged 1.53 kg/m3, evapotranspiration water use efficiency (ETWUE) values were higher than CWUE and varied from 2.0 to 2.3 kg/m3, averaging 2.1 kg/m3. Maize irrigation water use efficiency (IWUE) was varied with years and averaged 1.74 kg/m3. There were strong relationships between maize CWUE and maize seasonal irrigation amounts of IWUE and the seasonal irrigation amounts with R2 of 0.97 and 0.92, respectively. Maize CWUE increased linearly with maize IWUE with a coefficient of determination R2 of 0.99, while IWUE showed a strong quadratic relationship with ETWUE (R2 = 0.94). The results of this study can be used as a guideline for maize water management under the semiarid conditions in northwestern New Mexico and other locations with similar climate and management conditions. Irrigation requirements for maize should be adjusted to the local meteorological conditions for optimizing maize irrigation requirement and improving maize water productivity.

Water status, gas exchange and crop performance in a super high density olive orchard under deficit irrigation scheduled from leaf turgor measurements

We evaluated the suitability of scheduling a regulated deficit irrigation strategy in a hedgerow olive orchard with high plant density from leaf turgor related measurements. Measurements were made for two consecutive years at an olive orchard with 1667 ‘Arbequina’ trees per hectare where we had two deficit irrigation treatments, 45RDICC and 45RDITP, plus a full irrigation as a control. The two 45RDI treatments consisted on applying the same regulated deficit irrigation strategy, aimed to supply a total of 45% of the irrigation needs. The 45RDICC treatment however, was scheduled with the crop coefficient approach, while the 45RDITP treatment was scheduled with an irrigation scheduling approach based on leaf turgor related measurements, first suggested by Padilla-Díaz et al. (2016, Agric. Water Manage. 164:28–37). They worked at the orchard in 2014, and made a preliminary evaluation of the irrigation scheduling approach by comparing 45RDITP versus 45RDICC in terms of irrigation dose and frequency, predawn and midday stem water potential (Ψstem), and the fruit yields of each treatment. In this work, we considered the same variables as well as maximum daily values of stomatal conductance and CO2 net assimilation, the seasonal courses of the number of internodes in current-year shoots, leaf area and oil accumulation in the fruits, and total fruit and oil yields. All those variables were monitored both in 2014 and 2015, and we found no differences between the 45RDITP and the 45RDICC treatments, for any of them. The irrigation amounts applied to each treatment differed occasionally, but the total water supplies were similar to both 45RDI treatments. Our results, therefore, confirm the suitability of the irrigation scheduling approach proposed by Padilla-Díaz et al. (2016) to apply regulated deficit irrigation in commercial hedgerow olive orchards. We found additional evidence for the 15% changes on the irrigation amount recommended by the irrigation scheduling approach as being suitable for the orchard conditions. Caution must be taken when applying this approach to other olive orchards, since the relations between the tree water status and the shape of the daily curves recorded with the ZIM probes may depend on the cultivar and orchard conditions.

Water Resources of Georgia and Their Ecological Condition

Water resources are one of the most important natural resources of Georgia. Thereare 26060 rivers with total length 58987 km. A base of hydrographic network are smallrivers with length less than 25km and total length 50480 km.Georgia’s territory is dividedin two main regions: Black Sea basin and Caspian Sea basin. Total natural river runofffrom the territory of Georgia is 56.4km3 and to the territory (from Armenia and Turkey)- 8.74 km3. Thus, total water supplies amount for 65.4 km3. Rioni River is Imereti’smain artery of water. It is a left tributary of the largest river Imereti hills - Kvirila, which isconnected with Dzirula Chherimeloy, and the right side connects with the waters of theRioni Tskhenistskali. Rioni water is used in production, and communal services of thepopulation. On both sides of the Rioni are large industrial facilities that degrade waterquality. The problem of water resources protection in Imereti and rational use of it, onthe one hand, has created increasing demand for water by industry, and, on the otherside, of reservoirs pollution. Water pollution in the Rioni begins with the origins. Fromtraditional polluting facilities should be noted Kvaisskoe, Tutiyskoe businesses, a lot ofOni and Ambrolauri businesses that poured on the raw water in the Rioni. And the mostpolluted river in the territory of Kutaisi.

Estimation of Non-Revenue Water Ratio Using MRA and ANN in Water Distribution Networks

The non-revenue water (NRW) ratio in water distribution networks is the ratio of losses from unbilled authorized consumption and apparent and real losses to the total water supply. NRW is an important parameter for prioritizing the improvement of a water distribution system and identifying the influencing parameters. Though the method using multiple regression analysis (MRA) is a statistical analysis method for estimating the NRW ratio using the main parameters of a water distribution system, it has disadvantages in that the accuracy is low compared to the measured NRW ratio. In this study, an artificial neural network (ANN) was applied to estimate the NRW ratio to improve assessment accuracy and suggest an efficient methodology to identify related parameters of the NRW ratio. When using an ANN with the optimal number of neurons, the accuracy of estimation was higher than that of conventional statistical methods, as with MRA.

Impact of Deficit Irrigation on Yield and Fruit Quality of Orange Trees (Citrus Sinensis, L. Osbeck, CV. Meski Maltaise) in Southern Tunisia

AbstractAn experiment on deficit irrigation of orange trees (Citrus sinensis, L. Osbeck, cv. Meski Maltaise) with saline water (1.5 g l‐1) was conducted in the arid region of Medenine, Tunisia. Four irrigation treatments were applied: full irrigation (FI), irrigated at 100% of the crop evapotranspiration; deficit irrigation (DI75) and (DI50), which received respectively 25 and 50% less water than FI; and the farmer's method (FM). Soil water content and salinity were monitored during the orange active period. Yield and fruit quality were measured at harvest and used to analyse water productivity (WP) and net income. Results show a decrease in soil salinity between the spring and winter seasons with maximum values observed for the DI50 treatment. Maximum yield levels were obtained under the FI treatment (26.6 t ha−1). Applying continuous deficit irrigation resulted in 24 and 45% yield reduction respectively for DI75 and DI50, compared to FI. Fruit‐quality parameters showed significant differences, with higher levels of total soluble solids for DI50 and better fruit weight for FI and FM. For total water supplies between 415 and 786 mm, WP was in the range 2.9–3.6 kg m‐3, with the highest values observed for the DI50 treatment and the lowest for FM. The soil water balance‐based irrigation method (FI) generated the greatest net income and the lowest soil salinization. Reduction in water supply produced an equivalent reduction in yield but a much stronger decrease in the economic return: using the DI75 strategy resulted in 25% water saving, 24% reduction in yield and 40% reduction in net income. Copyright © 2020 John Wiley & Sons, Ltd.

China’s water situation; the supply of water and the pattern of its usage

Abstract This study specifically looked at total water supply in China, water withdrawal from various sources and various usage of water. From the analysis, it was realized that water supply from the underground source contributes greatly to the total water supply in China, a cubic unit withdrawal in underground water results in about 45% increase in the total water supply. Water from other sources also contributes to the total water supply in China. Water from other sources includes supplies from wastewater treatment, rain collection, seawater desalinization and other water projects. The result shows that a cubic unit increase in withdrawals from other sources results in about 3% change in gross water supply in China. A cubic unit withdrawal of water for industrial use results in about 29% increase in water use in China. For the agriculture sector, the result shows that a cubic unit increase in agriculture usage leads to approximately 67% increase in total water use in China. Water for household consumption, saw a 15% increase in total water usage in China for every cubic unit withdrawal.