Total Water Use Research Articles

Global supply chain drivers of water use in Sub-Saharan Africa: Taking Ghana as a case

Local water use is significantly affected by distant economies through global supply chains. Ghana is one of the largest trade hubs in sub-Saharan Africa, and large amounts of Ghana's water use are embodied in international exports. Previous studies have made efforts to evaluate direct water use in Ghana but overlooked nations and sectors indirectly driving Ghana's water use. This study explored global supply chain drivers of Ghana's water use during 2012–2021, based on the global environmentally extended multi-regional input-output (EE-MRIO) model. Results revealed that the total water use of Ghana was 9790 million m3 (Mm3) during this period. About 39% of Ghana's water use is attributed to foreign consumption and more than 12% is driven by the US and the UK. The domestic and foreign demand for the products of the “spices and pharmaceutical crops” sector is an important sectoral driver of Ghana's water use. From the supply side, domestic primary inputs account for 93.1% of the national water use whereas only 6.9% is attributed to foreign primary inputs. The domestic sectoral suppliers are mainly the “spices, and pharmaceutical crops” and “wholesale and retail trade” sectors. The critical foreign nations from the supply side are China and Cote d’Ivoire, enabling 88.5 Mm3 and 59.0 Mm3 of Ghana's water use respectively. Demand-side initiatives (i.e., consumer tax and education) and supply-side measures (i.e., efficient water use compliance) should be integrated with existing production-side policies to regulate sub-Saharan Africa's water use.

Acclimation of mature spruce and beech to five years of repeated summer drought – The role of stomatal conductance and leaf area adjustment for water use

Forests globally are experiencing severe droughts, leading to significant reductions in growth, crown dieback and even tree mortality. The ability of forest ecosystems to acclimate to prolonged and repeated droughts is critical for their survival with ongoing climate change. In a five-year throughfall exclusion experiment, we investigated the long-term physiological and morphological acclimation of mature Norway spruce (Picea abies [L.] KARST.) and European beech (Fagus sylvatica L.) to repeated summer drought at the leaf, shoot and whole tree level. Throughout the drought period, spruce reduced their total water use by 70 % to only 4–9 L per day and tree, while beech was less affected with about 30 % reduction of water use. During the first two summers, spruce achieved this by closing their stomata by up to 80 %. Additionally, from the second drought summer onwards, spruce produced shorter shoots and needles, resulting in a stepwise reduction of total leaf area of over 50 % by the end of the experiment. Surprisingly, no premature leaf loss was observed. This reduction in leaf area allowed a gradual increase in stomatal conductance. After the five-year drought experiment, water consumption per leaf area was the same as in the controls, while the total water consumption of spruce was still reduced. In contrast, beech showed no significant reduction in whole-tree leaf area, but nevertheless reduced water use by up to 50 % by stomatal closure. If the restriction of transpiration by stomatal closure is sufficient to ensure survival of Norway spruce during the first drought summers, then the slow but steady reduction in leaf area will ensure successful acclimation of water use, leading to reduced physiological drought stress and long-term survival. Neighboring beech appeared to benefit from the water-saving strategy of spruce by using the excess water.

Water productivity in Vitis vinifera L. cv. Alvarinho using dual crop coefficient approach

Water productivity (WP) measurement determines the efficiency of water use by assessing the ratio of the crop yield to the amount of water used in production. The objective of this study was to identify the optimal irrigation treatment for Vitis vinifera L. cv. Alvarinho with ground cover in Northern Portugal, with a focus on water productivity. Two irrigation treatments (full irrigation—FI; deficit irrigation—DI) and a control (rainfed—R) were considered. The FI strategy represented the standard irrigation carried out by the vinegrower, based on the water availability and their experience. The cover crop was a variable factor, evaluated in terms of both height and density, both within the crop row and between the rows. In each of the treatments, the available soil water content (ASW) was measured in eight locations in the field throughout the growing season using a capacitive probe (Diviner 2000) previously calibrated. These measurements were used to calibrate the SIMDualKc model, which employed the dual crop coefficient approach. The successful calibration of the model, carried out with treatment R in 2018, was evidenced by the strong correlation between the ASW measured through the capacitive probe and that simulated by SIMDualKc (b=0.988 and r2=0.995). After the model’s calibration, the separation between the transpiration and evaporation components was determined. The maximum transpiration during the growing season was observed in the full irrigation treatment. In this context, the study proceeded to apply the soil water balance components and transpiration generated by the model in the calculation of the WP. The fruit yield productivity was determined by accounting for the total water use in the growing season. The total water used was calculated by combining the volumes of water applied for irrigation and precipitation and the soil water extracted during the growing season by crops and cover crops. The deficit irrigation strategy showed the best performance in both years, with WP values of 3.31 and 1.81 kg m−3 for the years 2018 and 2019, respectively. Therefore, the study concluded that deficit irrigation proved to be the most effective irrigation strategy in terms of water productivity and crop water use efficiency (WUEc).

Effects of atmospheric CO2 concentration on transpiration and leaf elongation responses to drought in Triticum aestivum, Lolium perenne and Festuca arundinacea.

Leaf elongation is vital for Poaceae species' productivity, influenced by atmospheric CO2 concentration ([CO2]) and climate-induced water availability changes. Although [CO2] mitigates the effects of drought on reducing transpiration per unit leaf area, it also increases total leaf area and water use. These complex interactions associated with leaf growth pose challenges in anticipating climate change effects. This study aims to assess [CO2] effects on leaf growth response to drought in perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea) and wheat (Triticum aestivum). Plants were cultivated in growth chambers with [CO2] at 200 or 800ppm. At leaf six to seven unfolding, half of the plants were subjected to severe drought treatment. Leaf elongation rate (LER) was measured daily, whereas plant transpiration was continuously recorded gravimetrically. Additionally, water-soluble carbohydrate (WSC) content along with water and osmotic potentials in the leaf growing zone were measured at drought onset, mid-drought and leaf growth cessation. Elevated [CO2] mitigated drought impacts on LER and delayed growth cessation across species. A positive correlation between LER and soil relative water content (SRWC) was observed. At the same SRWC, perennial grasses exhibited a higher LER with elevated [CO2], likely due to enhanced stomatal regulation. Despite stomatal closure and WSC accumulation, CO2 did not influence nighttime water potential or osmotic potential. The marked increase in leaf area across species resulted in similar (wheat and tall fescue) or higher (ryegrass) total water use by the experiment's end, under both watered and unwatered conditions. In conclusion, elevated [CO2] mitigates the adverse effects of drought on leaf elongation in three Poaceae species, due to its impact on plant transpiration. Overall, these findings provide valuable insights into CO2 and drought interactions that may help anticipate plant responses to climate change.

Large agri-food corporations in the global staple and cash crops markets: a quantitative analysis of rice and coffee through the virtual water perspective

The paper investigates the influence of major food corporations on global rice and coffee markets from 2013 to 2022, with a focus on market presence and water usage. It uses detailed data from the Euromonitor Passport and the CWASI datasets to analyze environmental impacts and virtual water (VW) flows at the company level, addressing gaps in the existing literature. Key findings show that although rice sales are larger than those of coffee in quantity, coffee embeds a higher total water use due to its greater unit water footprint (WF). The rice market is less internationalized and concentrated compared to the coffee market, where a few companies hold significant market shares across multiple countries. In 2022, the top 12 rice-selling companies control 16% of the global rice WF, exceeding the combined WF of the top three rice-importing nations. Similarly, the top 15 coffee-selling companies command 55% of the global roasted coffee WF, with significant disparities in VW quantities compared to major importing nations. The coffee market exhibits a higher number of companies with larger shares of WF than volumes, with this disparity increasing over time. Furthermore, more countries exhibit high and moderate concentration indices for coffee sales compared to rice. These findings highlight the considerable concentration of water resources among large companies, particularly in the coffee sector. The paper emphasizes the importance of considering the environmental implications of corporate activities in food supply chains, providing valuable insights for sustainability efforts in the agri-food industry.

Study on the sustainable utilisation of water resources in semi-arid megacities of China based on water footprint

ABSTRACT As urbanisation continues to accelerate in China, the contradiction between rapid economic development and water scarcity in semi-arid cities is becoming increasingly evident. Consequently, the study of the relationship between water resources use and economic growth is of particular importance. Lanzhou City was selected as the study area, an evaluation index system was established to comprehensively evaluate the status of water resources utilisation, meanwhile, the water footprint method and Tapio decoupling model were adopted to measure the decoupling status between water utilisation and economic development from 2002 to 2021. The result showed that the total water footprint and per capita water footprint followed an increasing and then decreasing trend. The water footprint varied significantly by industrial sector, with agriculture accounting for 72.87% of total water use. The self-sufficiency rate of water resources was above 96.5%. The economic value increased substantially from 22.25 CNY/m3 in 2002 to 183.99 CNY/m3 in 2021. The water scarcity index and the pressure index were high, with annual mean values of 0.96 and 1, respectively. Water consumption and economic growth are generally decoupled weakly and strongly, with the number of strong decoupling occurrences increasing significantly from 2011 to 2021.

Quantification model of water use efficiency in indoor swimming venues based on behavioral analysis

Swimming venues provide various services based on water as the carrier, but studies on their water use are few. This study constructed a stochastic model to quantify the water use efficiency of indoor swimming venues under different scenarios based on Monte Carlo simulation. It explored the impact of shower behavior, swimming pool replenishment rate, and appliance water efficiency on water use efficiency in swimming venues. The results show that the indoor swimming pool replenishment volume and shower water use accounted for relatively high proportions and are relatively stable, with a total of about 81 % of the total water use; the model could effectively quantify the water demand in swimming pools under different scenarios. The theoretical water withdrawal of the swimming pool per unit volume under the saving mode and the reasonable mode are 26.32 m3/(m3·a) and 34.71 m3/(m3·a) respectively, which are comparable to the water use quota values of swimming venues by region in China. Conclusions could be drawn from sensitivity analysis that replenishment rate is the most important factor affecting the water withdrawal per unit volume of the swimming pool, followed by shower duration. This study provides theoretical basis for water-saving management to swimming venue managers, and reference for different industries to carry out research on the mechanism of water use behavior and water demand analysis.

Groundwater quality vs. groundwater quantity. Combining information on irrigator concerns with past water use and cropping behavior.

The effectiveness of groundwater in fulfilling crop water deficits depends on its quality and quantity. This paper examines the relationship between irrigators’ stated concerns over groundwater quality and groundwater quantity and their past water use and cropping decisions. Information on irrigator concerns over groundwater quality and quantity is obtained from 626 survey responses of agricultural producers in the Kansas portion of the High Plains Aquifer. We combine 20 years of field-level water use and cropping data with each of the 626 survey responses. We find that irrigators indicating elevated concern over either groundwater quality or groundwater quantity correlates with less total water use, fewer total irrigated acres, and fewer acres of irrigated corn. Additionally, concerns over groundwater quantity generally correlate with a greater reduction in water use along multiple water use margins compared to equal concerns over groundwater quality.

Microsprinkler irrigation in combination with nutrient management influences crop and water productivity and water-nutrient dynamics in large cardamom-growing soils in the hilly sub-Himalayan region of India

ABSTRACT A field experiment designed with three tiers of irrigation viz., I0: rainfed, I1: 100% crop evapotranspiration (1.0 ETc) and I2: 0.75 ETc and four tiers of soil nutrition viz., N0: control (no farmyard manure and fertilizer), N1: 100% recommended dose of fertilizer (RDF) as FYM, N2: 50% RDF as FYM +50% RDF as chemical fertilizers and N3: 100% RDF as chemical fertilizers was conducted for four consecutive years (2015–2018) on large cardamom at the hilly terrain of Gitdubling lower beyong busty in Kalimpong Block II in Darjeeling district of WB India. The results showed that I1N3 treatment combination providing microsprinkler irrigation at 1.0 ETc and full RDF (20:40:40::N:P2O5:K2O kg ha−1) recorded highest growth, yield attributes, fresh yield (665.2 kg ha−1) and dry yield (282.0 kg ha−1) of capsules, greatest water productivity (1.8 × 100 kg m−3) and largest soil availability and leaf accumulation of N, P and K. The soil water distribution along the phenological stages was inconsistent and followed the trend according to the rainfall amounts; however, the contents increased with an increase in soil depth and irrigation regime. The predictive regressive models showed the linear relationships between the dry capsule yield and irrigation water and total water use by the plant.

Improving mangoes' productivity and crop water productivity by 24-epibrassinosteroids and hydrogen peroxide under deficit irrigation

In nature, plants are frequently subjected to a wide range of abiotic stresses that drastically reduce crop productivity. Deficit in irrigation is one of the main factors of abiotic stresses that affect agricultural productivity. Nevertheless, not much research has been done on how to use water with brassinosteroids (Br) and hydrogen peroxide (H2O2)in deficit water conditions in order to reach comparatively good values of mango tree growth, productivity, and fruit quality as well as crop water productivity (WPC). A split-plot experiment in a complete randomized block system design study with 3 regulated deficit irrigation levels i.e. 100% IR (Irrigation requirement), 80% IR, and 60% IR was implemented in 2022 and 2023, each irrigation regime was combined with the foliar application of distilled water (control), 1 mg/L Br, 10 mM H2O2, 1 mg/L Br + 10 mM H2O2. Foliar treatments were applied at 3 different phenological stages: flower bud induction and differentiation, full bloom, and beginning of fruit set. The results showed that fruit shape index and acidity significantly improved as irrigation volume increased, however, the proportion of fruit mineral content and fruit chemical characteristics was inversely correlated with the volume of water. Meanwhile, moderate regular deficit irrigation (80% IR) achieved marked increases in leaf minerals and total chlorophyll content, fruit quality, yield, and water use efficiency. Drought stress (60% IR) significantly decreased fruit set, fruit retention, yield traits, and fruit physical and chemical properties, at the same time, significant improvements in the content of stress indicators (proline, total phenols, and carotenoids) were observed compared with control. All treatments with Br and H2O2 alone or in combination under drought stress had a pronounced effect in this regard. Overall, foliar spray of 1 mg/L Br+10 mM H2O2 was the most powerful treatment that emended the unpropitious effect of water stress.

Water use and yield response of rainfed safflower (Carthamus tinctorius L.) in Vertisols with varying soil depths

AbstractSafflower (Carthamus tinctorius L.) is an edible oilseed crop mainly cultivated in marginal lands. This study evaluates safflower crop water requirements to understand its feasibility to cultivate under rainfed ecosystem through a field experiment undertaken at the International Crops Research Institute for the Semiarid Tropics research farm, India. Eight improved and stress‐tolerant safflower cultivars (five spiny and three non‐spiny) were evaluated in Vertisols at three soil depths, that is, shallow: <0.60 m, medium: 0.60–1.20 m, and deep:1.20–1.80 m, over 3 years (2009–2012). Wet, normal, and deficit rainfall years were experienced during 2009/2010, 2010/2011, and 2011/2012, respectively. Soil moisture, crop yield, and growth parameters were measured, and field‐scale hydrology was captured through a calibrated one‐dimensional water balance model. Safflower responded to available residual soil moisture which varied with soil depth and rainfall received in different years. Total crop water use was 300–320 mm during the postrainy season, of which about 70% was extracted in deep Vertisols and 55% in medium Vertisols through residual soil moisture. In addition, 30% of water requirement was met through postrainy season rainfall. Safflower grown in shallow Vertisols could only meet 40% of crop water requirement. Spiny cultivar NARI‐H‐15 grown in deep soil recorded a maximum yield of 1890 kg ha−1 in the wet year. Seed yield from spiny cultivars grown in deep and medium soils was nearly similar (1500–1600 kg ha−1) during wet and normal years; a significant reduction in yield (>50%) occurred in shallow soils and also during a rainfall deficit year. Spiny cultivars produced 10%–50% higher seed yield compared to non‐spiny cultivars. Growing safflower in medium and deep Vertisols provides opportunities for crop intensification.

Aligning health, environment, and cost aspects of diets: Identifying sustainable dietary patterns in China

Considering the adverse effects of agricultural-food systems on both human health and the environment, this research aimed to identify sustainable diets, which are nutritious, culturally acceptable, affordable, and have low environmental impacts, based on self-reported diets in China. Dietary data was collected with a 3-day 24-h dietary recall and weight food record combined method among 10,324 subjects aged 18–64 year, who participated in the China Health Nutrition Survey 2011. Diet quality was assessed by the Chinese Healthy Eating Index 2016 (CHEI2016). Environmental impact was measured by greenhouse gas emissions (GHGE), total water use (TWU), and land use (LU), and diet costs were calculated using market prices of community surveys. Reduced rank regression derived dietary patterns with 34 food groups as predictor variables, and used CHEI2016 score, dietary greenhouse gas emissions (GHGE), total water use (TWU), land use (LU), and cost of the diet as response variables. Four dietary patterns were identified. Participants with the highest adherence (decile 10) to the “High animal-based food” pattern showed higher dietary GHGE (+57%), TWU (+51%), and LU (+54%) and dietary costs (+64%), compared to the average population's diets. The diet in decile 10 for the “High fruit, low ruminant meat” pattern displayed a 21% higher CHEI2016 score, and higher dietary environmental impact (GHGE +17%; TWU +22%; LU +19%) and dietary costs (+46%) than the average diets. Diets of participants who followed the “High fish, low beverages” pattern showed higher environmental impact (GHGE +39%; TWU +32%; LU +28%) and dietary costs (+19%), but the CHEI2016 score was similar (+0.1%). Finally, the “High wheat, low pork” pattern demonstrated lower environmental impacts (GHGE -17%, TWU -12%, LU -2%) and lower cost of the diet (−2%) but also lower CHEI2016 score (−1%) compared to average population. This study reveals the complex trade-offs between diet quality, environmental sustainability, and dietary costs of current dietary patterns. None of the four patterns achieved the desirable combination of high CHEI2016 scores, reduced environmental impact, and reduced dietary costs. The findings offer insights into sustainable diet choices within the current food system, suggesting dietary guidelines should consider environmental sustainability and cost-effectiveness.

Optimal Allocation of Water Resources in Canal Systems Based on the Improved Grey Wolf Algorithm

Xinjiang is located in the arid region of northwestern China, and agriculture accounts for an absolute share of total water use. Resource-based, engineering, structural, and managed water shortages coexist. Therefore, it is of great significance to vigorously develop water conservation technology and improve the efficiency of water transmission and distribution in canal systems. This research aims at addressing the problems of difficult manual regulation and the overall optimization of the final canal system, low-water-resource utilization efficiency, and management efficiency. Taking the branch-double two-stage canal system of Dongfeng branch canal in Mangxiang, Jinghe irrigation district, as a case study, and the rotation irrigation group and irrigation duration as decision variables, canal distribution is modeled with the goal of minimizing seepage losses. The improved grey wolf algorithm combined with particle swarm optimization is used for the first time and compared with the traditional grey wolf algorithm, genetic particle swarm optimization fusion algorithm, and northern goshawk algorithm. The results show that (1) on the basis of meeting the water discharge capacity and water demand requirements of the canal system, the diversion time of the water distribution scheme obtained by using the improved grey wolf algorithm is shortened from 11 d to 8.91 d compared with the traditional empirical water distribution scheme. (2) The improved grey wolf algorithm converges to the optimal value within 10 generations compared to the remaining methods, and the total water leakage is reduced from 16.15 × 104 m3 to 11.75 × 104 m3. (3) The number of gate adjustments is reduced, and the canal gates are opened and closed at the same time within each rotational irrigation group. The grey wolf algorithm improved by its combination with particle swarm has stronger optimization ability and convergence, which can better meet the requirements of efficient water resource allocation in irrigation canal systems, as well as a high application value.

Valuation of the Teesta River water by Hydro Economic Model

Hydro-Economic Models (HEMs) are powerful tools to analyse water scarcity and water management problems. The Teesta River which flows from India to Bangladesh has long been a source of dispute between India and Bangladesh. A win–win solution for the problem is important for the 1.2 billion people of the two neighboring countries. A Hydro-Economic Model (HEM) on the Teesta may provide sufficient information for the solution of the dispute. Most HEMs that treat transboundary water issues consider a narrow scope of water values including agriculture, hydropower, municipal, and tourism. However, water has many additional values. This study adds to the HEM literature by considering the values of fisheries, navigation, environment or sediment transport. A Teesta Hydro-Economic Model (THEM) was developed to represent a large range of economic values of water use during the dry season. Results show that the total water use value for a dry season is USD 41.5 million for India and USD 77 million for Bangladesh. The study shows that the benefit per unit volume of water for hydropower is the lowest among all types of water use. After performing an economic analysis, this study found a potential for trade-off between hydropower use in India and environmental use in Bangladesh. This study gives an idea about how to maximise the benefits from the river and how to mitigate the water sharing dispute.

HESS Opinions: The unsustainable use of groundwater conceals a “Day Zero”

Abstract. Water scarcity is a pressing global issue driven by increasing water demands and changing climate conditions. Based on novel estimates of water availability and water use in Chile, we examine the challenges and risks associated with groundwater (GW) withdrawals in the country's central-north region (27–35° S), where extreme water stress conditions prevail. As total water use within a basin approaches the renewable freshwater resources, the dependence on GW reserves intensifies in unsustainable ways. This overuse has consequences that extend beyond mere resource depletion, manifesting into environmental degradation, societal conflict, and economic costs. We argue that the “Day Zero” scenario, often concealed by the uncertain attributes of GW resources, calls for a reconsideration of water allocation rules and a broader recognition of the long-term implications of unsustainable GW use. Our results offer insights for regions worldwide facing similar water scarcity challenges and emphasize the importance of proactive and sustainable water management strategies.

Determination of the Effects of Different Irrigation Levels and Vermicompost Doses on Water Consumption and Yield of Greenhouse-Grown Tomato

This study was conducted in pots under a polycarbonate greenhouse to determine the effects of different irrigation levels and vermicompost doses on the morphological and phenological characteristics, water consumption, water use efficiency, and yield parameters of tomato plants. For this purpose, different irrigation levels of 100%, 75%, 50% (I100: full irrigation, I75, I50) and vermicompost (VC) doses of 0, 10% and 20% (VC0, VC10 and VC20, w/w) were applied as the treatments. The study’s results determined the irrigation levels and vermicompost doses affected the tomato plants’ morphological and fruit quality parameters. The highest and lowest plant water consumption (ET) values for the treatments were determined as 47.8 L (I100VC10) and 21.2 L (I50VC0), respectively. Moreover, irrigation water levels and vermicompost doses significantly influenced the total yield of tomatoes. The highest and lowest total and marketable yields were obtained from the I100VC20 and I50VC0 irrigation levels and vermicompost doses. Similarly, the highest and lowest total water use efficiencies were achieved from the I100VC20 (21.9 g L−1) and I50VC0 (11.0 g L−1) treatments. Furthermore, the highest and lowest marketable water use efficiencies were obtained from the I100VC20 (21.9 g L−1) and I50VC0 (7.8 g L−1) treatments. The yield response factor (ky) was found to be 1.42. Although the highest efficiency was achieved from 100% full irrigation and a 20% vermicompost dose in the study, it is suggested that 75% irrigation level and 10% fertilizer doses can also be applied in places where water is limited and fertilizer is expensive. The results revealed that the appropriate irrigation level and vermicompost doses could reliably be used to enhance tomato yield.

Developing a model to assess the impact of farm dams and irrigation for data-scarce catchments

ABSTRACT Productive agricultural supply chains require the support of functional ecosystems, but intense agricultural practices change local hydrological systems (e.g. river diversion). In this study, the impact of farm dams was assessed for the Verlorenvlei catchment, a sensitive ecosystem currently under a state of hydrological change in South Africa. We developed a new module for the Jena Adaptable Modelling System (JAMS)/J2000 rainfall–runoff model to assess the streamflow impact from the points of abstraction, losses during storage and irrigation. The model achieved a satisfactory streamflow calibration with efficiencies Nash Sutcliffe Efficiency (NSE, logNSE) of 0.52 and 0.51. The irrigated area reduced simulated streamflow by 12 to 19%. The results from the study agree with remote sensed evapotranspiration, measured lake surface water levels and streamflow, but uncertainty remains in the total simulated am evaporation. While many catchments lack the data required for a detailed irrigation impact assessment, this approach considers total water use, dam storage to area relationships and general farming practices.

Sustainability Approach of Recycled Denim Fabrics with a Life Cycle Assessment

Abstract In this study, denim fabrics were produced using weft yarns obtained from mechanically recycled fibers after consumer use, and the breaking strength, tearing strength, thermal resistance, water vapor permeability, air permeability, and fabric stiffness of these fabrics were determined according to the standards. A life cycle analysis of the recycled denim fabrics was made using the SimaPro software program, and the environmental effects of the production were also revealed. Within the scope of the study, it was observed that the structural properties of the fabrics produced and the composition of recycled cotton used affect the performance and comfort properties of the fabric. The effect of the cotton recycling rate on the recycled denim fabrics was evaluated by LCA (life cycle analysis). As a result of the LCA evaluation, with the use of cotton with a high percentage of recycling additives instead of the conventional cotton, as in the reference fabric, resource depletion (fossil fuels), global warming, depletion of the ozone layer, the toxic effect on human, freshwater and terrestrial life, the total water use, and other categories were observed to undergo a significant improvement.

Study on the Optimization of Wujiang’s Water Resources by Combining the Quota Method and NSGA-II Algorithm

Recently, the Chinese government has implemented stringent water requirements based on the concept of ‘Basing four aspects on water resources’. However, existing research has inadequately addressed the constraints of water resources on population, city boundaries, land, and production, failing to adequately analyze the interplay between water resource limitations and urban development. Recognizing the interconnectedness between urban water use and economic development, a multi-objective model becomes crucial for optimizing urban water resources. This study establishes a nonlinear multi-objective water resources joint optimization model, aligning with the “Basing four aspects on water resources” requirement to maximize urban GDP and minimize total water use. A genetic algorithm (NSGA-II Algorithm) is applied to solve this complex nonlinear multi-objective model and obtain the Pareto solution set, addressing information loss inherent in the traditional water quota method. The model was tested in Wujiang District, an area located in China’s Jiangsu Province that has been rapidly urbanizing over the past few decades, and yielded 50 non-inferior water resource optimization schemes. The results reveal that the Pareto solution set visually illustrates the competition among objectives and comprehensively displays the interplay between water and urban development. The model takes a holistic approach to consider the relationships between water resources and urban population, land use, and industries, clearly presenting their intricate interdependencies. This study serves as a valuable reference for the rational optimization of water resources in urban development.

The Connection between Phuket’s Water Supply and the Hotel Sector’s Water Use for Assessment of Tourism Carrying Capacity

For tourism development in areas where there are frequent problems with water shortage, it is important to assess water use potential from a geographic perspective. This study investigated the relationship between water use in the hotel sector and the amount of available water in Phuket for tourism carrying capacity assessment. Geographic information system (GIS) was applied to support spatial analysis. The studied hotels were in the size required to conduct an environmental impact assessment (EIA), totaling 178 hotels. There would be a total water use of 24,275 m3/day and 40,457 m3/day in the low and high seasons, respectively. In terms of annual water use, in the cases of lowest, normal, and highest possible consumption, there would be water consumption amounts of 8,860,021 m3/year, 11,303,606 m3/year, and 14,766,699 m3/year, respectively. From evaluating the capacity to support tourists in terms of water adequacy in Phuket Province, our results reveal that the amount of water in the province is insufficient to meet the needs of tourists. This is because the number of tourists coming to travel each year is ordinarily more than 10 million people, and there is a plan to accommodate 12 million tourists in 2023, but the amount of water that the province can procure is sufficient to support a maximum of not more than 8,986,600 tourists per year only if the water that EIA hotels store and produce themselves is included. This amount of water is still insufficient for the targeted number of tourists and other sectors, and the province’s water demand is likely to increase. In this regard, Phuket should hastily prepare a plan and measures to increase the amount of available water within the province.