Domestic Water Use Research Articles

Ecological Sustainability Assessment of Water Distribution for the Maintenance of Ecosystems, their Services and Biodiversity

Water provision and distribution are subject to conflicts between users worldwide, with agriculture as a major driver of discords. Water sensitive ecosystems and their services are often impaired by man-made water shortage. Nevertheless, they are not sufficiently included in sustainability or risk assessments and neglected when it comes to distribution of available water resources. The herein presented contribution to the Sustainable Development Goals Clean Water and Sanitation (SDG 6) and Life on Land (SDG 15) is the Ecological Sustainability Assessment of Water distribution (ESAW-tool). The ESAW-tool introduces a watershed sustainability assessment that evaluates the sustainability of the water supply-demand ratio on basin level, where domestic water use and the water requirements of ecosystems are considered as most important water users. An ecological risk assessment estimates potential impacts of agricultural depletion of renewable water resources on (ground)water-dependent ecosystems. The ESAW-tool works in standard GIS applications and is applicable in basins worldwide with a set of broadly available input data. The ESAW-tool is tested in the Danube river basin through combination of high-resolution hydro-agroecological model data (hydrological land surface process model PROMET and groundwater model OpenGeoSys) and further freely available data (water use, biodiversity and wetlands maps). Based on the results, measures for more sustainable water management can be deduced, such as increase of rainfed agriculture near vulnerable ecosystems or change of certain crops. The tool can support decision making of authorities from local to national level as well as private enterprises who want to improve the sustainability of their supply chains.

Study on Performance Improvement of Sodium Acetate Trihydrate in Thermal Energy Storage System by Disturbance

Phase change materials (PCM) have been widely used in Thermal Energy Storage (TES) Systems. Considering the energy efficiency and the use of domestic hot water, the melting temperature range of phase change materials is considered to be optimal in the range of 50–60 °C. The most commonly used is sodium acetate trihydrate-based phase change material, which has the advantages of high latent heat and low price, but its high supercooling, low thermal conductivity, and phase separation affect its application. Therefore, this paper used sodium acetate trihydrate, disodium hydrogen phosphate dodecahydrate (DSP), and expanded graphite (EG) as raw materials to prepare composite phase change materials (CPCM) and used physical disturbance to further improve their properties. Firstly, their thermophysical properties were investigated by the step cooling curve method, differential scanning calorimetry (DSC), and x-ray diffraction (XRD). Secondly, in order to further evaluate the effect of physical disturbance on CPCM crystallization, further experimental studies were carried out by adjusting the rotor mass and rotational speed. The experimental results showed that when 1.5 wt.% DSP, 1.5 wt.% EG and physical perturbation work together, the CPCM phase transition temperature is 56.7 °C, and the latent heat is as high as 258.98 kJ/kg. At this time, its thermal conductivity increased from 0.62 w/m·k to 1.1625 w/m·k, and its subcooling degree decreased from above 20 °C to less than 0.5 °C, and no phase separation occurred. The greater the disturbance momentum (the greater the rotor mass or the greater the rotational speed), the shorter the induction time, which is more conducive to the crystallization of CPCM. The results obtained in this paper are instructive for the preparation of efficient new CPCMs.

Dynamic heating control measured and simulated effects on power reduction, energy and indoor air temperature in an old apartment building with district heating

This study investigated the effects of the dynamic heating control on power reduction and indoor air temperature in a typical Finnish block of apartments built in 1981. The building operated in 2018 with conventional and in 2020 with dynamic heating control. The onsite measured data was collected from both periods. Measured data enabled calibrating the whole building simulation models with an accuracy better than 10%. A new dynamic heating curve control algorithm was developed so that outdoor air compensated supply temperature was reduced during high use of Domestic Hot Water (DHW) by applying DHW compensation differential. If the indoor air temperature in any apartment dropped below the limit, supply temperature uplift was applied. The dynamic heating control resulted in 8.9% space heating and 13.7% total heating power reduction while had practically no effect on energy use. On the contrary, dynamic heating control slightly increased indoor temperature fluctuations, but both control systems resulted in a similar value of hours below the setpoint temperature of 21 °C. The results demonstrate that heating power reduction without compromising indoor air temperature is possible with applied supply temperature drop during DHW peaks and preheating afterwards.

Response of Domestic Water in Beijing to Climate Change

Beijing, a megacity in northern China, has been long facing the challenge of water scarcity, and the problem of domestic water scarcity has been becoming more serious in recent years due to climate change and global warming. To cope with the adverse effects of climate change, it is urgent to build a prediction model for water consumption in Beijing under the background of climate change. Here, a climate domestic water use model was established based on the historical meteorological data and domestic water use data, and the future domestic water demand in Beijing and the response of domestic water use to climate change were projected. The results showed that the climatic water consumption in Beijing will increase with climate warming by 177.23 million m3/°C, and the per capita annual water consumption will increase by 8.1 m3/°C. Combined with the CMIP6 multi-model climate change scenario data, the climate domestic water consumption in Beijing in 2035 under the four scenarios of SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 will be 169 million m3, 189 million m3, 208 million m3, and 235 million m3 respectively; by 2050, the climate domestic water consumption in Beijing will reach 338 million m3, 382 million m3, 395 million m3, and 398 million m3, respectively. Under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, if all the increased climate domestic water consumptions are supplemented by groundwater, compared with 2019, the groundwater depth will decrease by 0.18 m, 0.22 m, 0.27 m, and 0.32 m in 2035, respectively, and the area of funnel area will increase by 6.84 km2, 8.48 km2, 10.11 km2, 12.34 km2 respectively. Compared with 2035, the groundwater depth in 2050 will decrease by 0.37 m, 0.43 m, 0.41 m and 0.36 m, respectively, the area of funnel area will increase by 14.13 km2, 16.21 km2, 15.61 km2, and 13.68 km2, respectively. If the increased climatic water consumption in Beijing is supplemented by external water transfer, the cost of external water transfer in 2035 will increase by CNY 391 million, CNY 485 million, CNY 578 million, and CNY 706 million, respectively, compared with that in 2019 under the four scenarios. Compared with 2035, the cost of external water transfer in 2050 will increase by CNY 808 million, CNY 927 million, CNY 893 million, and CNY 783 million, respectively.

Seasonal Variability of Water Quality in the Zigi River, Northern Tanzania

Water quality parameters (colour, total suspended solids (TSS), turbidity, electrical conductivity (EC), pH, dissolved oxygen (DO), total dissolved solids (TDS), temperature, nitrate, phosphate and faecal coliform) were evaluated during wet and dry seasons in relation to human activities in Zigi River and its tributaries. Samples were taken from nine strategic sampling points located in different areas of river. The samples were processed and analysed using established procedures. Results of temperature, EC, TDS, TSS, nitrate, colour, turbidity and E. coli were higher in wet season than in dry season. Significant variations (p < 0.05) of temperature, EC, TDS, nitrates, colour and turbidity with changing seasons were observed. Also, results on variations of other parameters were more or less the same in both seasons. Temperature, EC, TDS, nitrate and E. coli were increasing and DO decreasing downstream in both seasons probably due to increased anthropogenic activities along the river. High Pearson correlation coefficient (r2 > 0.53) observed between these parameters indicated that these values are closely related. Results on assessment of water using water quality index have revealed that the river water in both seasons is unsuitable for use as drinking water and that the water is more unsuitable for use during the wet season than during the dry season. Implications of the findings on water treatment are vivid and immediate measures are recommended to minimise the further diminishing quality of the water in this river and thus reduce the costs of treating the water for domestic use

Impact of urbanization and stormwater infrastructure on ephemeral channel transmission loss in a semiarid watershed

Study regionMontoyas watershed in central New Mexico, a rapidly urbanizing basin characteristic for the semiarid Southwestern United States. The 142 km2 watershed drains to the Rio Grande. Study focusThis study evaluated the impacts of urbanization and stormwater infrastructure on ephemeral channel transmission loss (TL), an important source of groundwater recharge in dryland basins. A hydrologic model (HEC-HMS) was built for the watershed and calibrated based on seven years of precipitation and discharge data. The model was then used to simulate the individual and combined impacts of land use change (urbanization) and stormwater infrastructure (ponds, channel lining) on runoff and transmission losses over a ten-year period based on observed storm events. New hydrological insights for the regionResults show high inter-annual runoff variability with the two wettest years contributing 44–59% of the 10-year total, and dry years resulting in nearly no flow. Both runoff and TL increased with urbanization. Assuming natural ephemeral channels, TL comprised 64–81% of runoff reaching the basin outlet and 7–10% of domestic water use in the basin, depending on urbanization scenario. Stormwater detention ponds had minimal impact on TL; however, lining the lower 5, 10 and 15 km of ephemeral streams reduced TL by 31%, 55% and 73% over the ten-year study period. Results indicate that preservation of ephemeral channels, in particular permeable channel beds, should be considered a viable strategy for managed aquifer recharge in urbanizing areas.

Development of a Water-Pricing Model for Domestic Water Uses in Dhaka City Using an IWRM Framework

Dhaka city is experiencing high water use and rapid declination of groundwater. The current water price in the city is low and based on a uniform rate. To arrest the resource degradation along with pursuing cost recovery and promoting social equity, this paper develops a new pricing model for domestic water uses using the integrated water resources management principles. The development is accomplished through estimation of domestic water usage, evaluation of current water prices, and assessment of groundwater degradation externalities in the Tejgaon area of the city using both primary and secondary data. Two economic and two environmental externalities are incorporated. The model is based on an increasing block tariff strategy, and the estimated unit prices for the first and second blocks are respectively 5% and 75% higher than the existing price. The model has the potential to reduce the domestic water use in the city by up to 27%, increase the revenue for the Dhaka Water Supply and Sewerage Authority by up to 75%, and reduce the water bill for poor households by up to 67%. The model has a great potential for practical deployment and the concept can also be applied to other cities and water uses.

WATER RESOURCE MANAGEMENT UNDER CLIMATE CHANGE: IMPLICATIONS FOR SUSTAINABLE USE ON KARST TERRAIN

The scarcity of freshwater is a critical issue that continuously is considered to be important around the world. The availability of freshwater steadily decreases because of growing population, high water demand and global climate change. Underground streams water and aquifers within karst terrain is assessed as an substantial factor of water supply systems in karst areas, and in the case that is assessed in this paper as well. Therefore, water management on karst area is essential to solve water deficiency problems, particularly during dry season. In this paper, management of karst spring water is discussed based on some cases from Citatah karst. Management of spring water is the main object of this paper that use mix method design, incorporating a qualitative and a quantitative approach. Result showed that inadequate human resource, infrastructure, database system; lack assertiveness, supervision and instrument of rules implementation; and low level of awareness and participation are found as the main factor of poor management of karst spring water at Citatah karst. However, better management could be attained by improving capacity building, strengthening monitoring capabilities, formulation of groundwater policy, implementing economic and financial instruments, improving participatory management and applying sustainable technology for agricultural and domestic water use.

Domestic water use and water-saving countermeasures in the process of urbanization in 2021: Jiaozuo City case study.

Water-saving scientifically proved measures are crucial to reduce the use of decreasing fresh water resources. In this study, we investigate the current situation of residents' domestic water use, analyze the current situation of residents' water-saving measures, the current situation of residents' water-saving consciousness and its influencing factors. We performed a questionnaire survey and data obtained by relevant water supply departments, this paper used SPSS 19.0 and Excel 2020 software to conduct statistical analysis of survey data. Our results show that: (1) overall, the water consumption of urban residents in the central plains suburb is 18% higher than that of the original urban residents. (2) Among the residential water structures, washing, washing clothes and flushing toilets are the most frequent tasks, accounting for 87.3% of the total water consumption. (3) The implementation of water-saving measures by the original urban residents is better than that of the original suburban residents. (4) It is necessary to increase effective water-saving facilities and measures for urban water use.

Research on the chemical compositionof water resources for gene conservationand development of H’mong cattle value chain in the northern mountainous region

The science and technology project “Application of technology to develop high-quality beef cattle into goods according to the value chain in the northern mountainous region” (hereinafter referred to as the H’mong cattle project) is implemented under Decision No. 1754/2018/QD-BKHCN dated June 25, 2018, of the Minister of Science and Technology. This is a national science and technology project implementing the application of new technologies to develop products according to the quality beef value chain in the northern mountainous provinces. The project is located at Dong Luong village, Quang Chu commune, Cho Moi district, Bac Kan province, that is oriented to develop a nuclear cow herd that preserves the H’mong gene. In cow breeding, water source plays a very important role in the growth and development of cows. In the project area, water for domestic use is often taken from wells or surface water from ravines, which have high hardness and heavy metals pollution, NO2- or E. coli. In order to ensure water quality for the Centre for Genetic Conservation and Development of H’mong cattle, for raising original H’mong cows, the authors have conducted experiments to study heavy metal content in the surface water samples (from rock ravines) and groundwater samples (fromdrilled wells). Water samples were taken at different times of the year and analysed by modern equipment with high sensitivity, high accuracy, and detection limit to ppt (ng/l). Measured results are compared with the QCVN 01-1:2018/BYT National Technical Regulation on Domestic Water Quality issued by the Ministry of Health.

Impact of saltwater intrusion on relation to fruit growing households in Ben Tre, Vietnam

Purpose. Saltwater intrusion affected seriously the livelihood of mangosteen growers in Ben Tre, a coastal province in the Vietnamese Mekong Delta in 2016. This study assesses how saltwater intrusion influenced the livelihood vulnerability of the mangosteen households and communities.
 Methodology / approach. This study used the United Nations’ Livelihood Vulnerability Index (LVI) and a similar index from the Intergovernmental Panel on Climate Change (LVI-IPCC) using data from 196 interviewed mangosteen growers in Cho Lach district, Ben Tre province in 2016 and 2018. A total of twenty-five (25) indicators are applied to calculate the two indices, using data as exposure to saltwater intrusion and natural hazards (5), socio-demographic factors (11), and sensitivity of health, finance, and source of water for domestic use (9).
 Results. The analysis results show that mangosteen-growing households had a medium vulnerability in 2016 and 2018 based on both indices. However, they were extremely vulnerable due to saltwater intrusion in 2016, and a high household percentage had a moderate value in the vulnerability index. They did not experience how to respond to saltwater intrusion and received a late warning on saltwater intrusion from the local authorities and media. However, mangosteen-growing households had a quick adaptive behavior to shift to new crops to improve their income in 2018.
 Originality / scientific novelty. The study provides a set of indicators to assess the vulnerability of this low-vulnerable area based on past studies as well as the actual situation of the study area in 2016 and 2018 to determine what factors influenced the main components, LVI and LVI – IPCC. These indicators represented the characteristics of the rural households in Vietnam and other Asian countries. This research also indicated how LVI and LVI – IPCC results differently and when they should be used. The analysis identified the factors influencing the LVI and LVI – IPCC by levels of saltwater intrusion in different years of 2016 and 2018, two different severe and less severe sites, adaptive and non-adaptive households, and their interaction. 
 Practical value / implications. LVI and LVI-IPCC are good indicators for local and regional assessments on how saltwater intrusion and natural hazards affect households’ and communities’ livelihood and thereby how to guide them to respond promptly in such cases.

Index System of Water Resources Development and Utilization Level Based on Water-Saving Society

The notion of a ‘Water-saving society’ may help China achieve sustainable development and high-quality development. In this paper, the concept of water resources development and utilization level is discussed from the perspective of a water-saving society, and an evaluation index system including 33 indicators is constructed. This paper takes the evaluation of water resources development and utilization level of Jingyu County from 2009 to 2018 as an example to verify the rationality of the indicator system of this study. Additionally, by changing the sensitivity analysis method of indicator weights, the indicators with greater influence on the evaluation results are screened to reduce the uncertainty of too many indicators and low correlation. The results show that the evaluation value of water resources development and utilization level in Jingyu County from 2009 to 2018 was improved from V to II, and the improvement of industrial and domestic water use efficiency and effectiveness improved the water resource problems in the study area. Sensitivity analysis showed that the sensitivity parameters are the degree of water resources development and utilization (8.7%), water consumption per CNY 10,000 of industrial value added (11.2%), water consumption per CNY 10,000 of GDP (9.3%), leakage rate of the urban water supply network (8.4%), per capita water resources (10.1%), per capita COD emissions (9.3%) and urbanization rate (8.2%).

Prediction of Water Consumption in 31 Provinces of China Based on FGM(1,1) Model

AbstractHuman production activities and social development cannot be separated from the indispensable water resources. In recent years, with the increasing speed of China's economic development, the consumption of water resources has gradually become the focus of attention of the Chinese government and the public. Based on the original data of water use of 31 provinces (municipalities and autonomous regions) in China from 2014 to 2018, a fractional order accumulative gray prediction model (FGM(1,1)) is established to predict the water use of 31 provinces (municipalities and autonomous regions) in China in the short term, and the applicability of the model is verified by the mean absolute percentage error (MAPE) value. According to the MAPE value, the data obtained by the FGM(1,1) model is relatively accurate. The prediction results show that in case of little change in total water consumption, agricultural water and industrial water use show a downward trend, while domestic water use shows an upward trend. The government's water management policy for urban residents needs to be adjusted, and the publicity work to improve the water‐saving awareness of urban residents needs to be improved.

The ecological tradeoffs of desalination in land-constrained countries seeking to mitigate climate change

The global demand for desalinated water is increasing at a remarkable rate. In a future with increasing demand for water and low-carbon electricity, an interesting ecological dilemma emerges. In a decarbonized world, providing desalinated water for domestic use and aquatic ecological restoration could increasingly come at the expense of open space lost to renewables such as solar photovoltaics (PV) and wind turbines. In this article we examine the environmental tradeoffs of providing freshwater from desalination under a solar photovoltaic-based decarbonization strategy, using Israel as an example. Israeli policymakers are tasked with finding an acceptable balance between reducing CO2 emissions, increasing water supply for human consumption, preserving open space, remediating aquatic ecosystems, and aiding Palestinian and Jordanian neighbors in efforts to mitigate the risks associated with acute water shortages. We simulate future 2050 ecological tradeoffs from largescale desalination in Israel under a “business-as-usual”, a “nature-matters”, and a “nature-and-cooperation-matter” scenario. We find that the solar PV required for generating electricity for desalination alone could take up an area more than half the size of Israel's second-biggest city, Tel Aviv. The marginal impact of an additional loss of 37 km2 of open space is difficult to predict, but if ecological corridors or critical habitats are affected, it could be catastrophic for many stressed species and ecosystems across Israel.

Water productivity in cultivating the cowpea under different production systems

The increase in irrigated areas and the water crisis in numerous regions have encouraged the use of irrigation systems and management that afford greater efficiency in the use of water. Wastewater is one option for maximising this efficiency. The aim of this study was to evaluate the indicators of water productivity in the cultivation of irrigated cowpea under different production systems. The study was carried out in the experimental area of the Sewage Treatment Station (ETE) located in Tianguá, Ceará. The experiment consisted of six production systems (treatments) in subdivided plots distributed in a completely randomised design (CRD) with fifteen replications in a (2 x 3) factorial scheme, i.e. two sources of water and energy: drinking water + electricity from the electrical grid (conventional system) and wastewater + solar photovoltaic energy (alternative system), and the different sources of fertiliser (mineral and organic), in addition to the control treatments. The water productivity indicator that expresses the relationship between the yield of the crop and the volume of water applied was determined, and the index in economic terms between crop yield and the volume of water applied. The system using wastewater and organic fertiliser showed better water productivity, 0.422 kg m-3, while the system that used drinking water with no fertiliser showed less efficiency, 0.188 kg m-3. Water use efficiency in the systems that used wastewater was higher in relation to the systems that used drinking water. Irrigation with treated domestic effluent increases water productivity and water use efficiency, in addition to being a strategy for agricultural exploitation under conditions of water scarcity

Water quality assessment and potential ecological risk of trace metals in sediments of some selected rivers in Vhembe district, South Africa

The monitoring of river health systems is crucial to maintain the integrity of services derived from them. This study investigated the physicochemical and microbiological levels in some tributaries of the Luvuvhu River water and sediments in South Africa. High levels of cadmium were recorded in the sediments of most of the rivers capable of posing high risk to aquatic organisms. The severity of the other metals ranged from low to medium risk. Comparable results on the effects of trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) on aquatic biota were obtained using various ecological indices (such as contamination factor, degree of contamination and potential ecological risk) and sediment quality guidelines (such as threshold effect level and the probable effect level of the Canadian council of the Environment (CCME) and the effect range-low and effect range-median). High levels of faecal indicator organisms (>59,000 cfu/100 mL) were recorded in all water source that are often used for domestic and agricultural purposes. The decreasing trend of faecal indicator organisms in the selected rivers were in the order: Mvudi > Mudidaba > Dzindi > Luvuvhu > Dzondo. Hence the use of the water for domestic purposes possess a potential acute human health risk. The levels of trace metals obtained from this study were above the threshold levels of water used in aquaculture though most of them complied with the regulatory limit for domestic and irrigation water use in some of the rivers. The decreasing trend of average trace metals levels were in the order: Mvudi > Mudidaba > Dzondo > Luvuvhu > Dzindi. The water quality of some of the tributaries of the Luvuvhu river (Mvudi and Mudidaba) were found to be more contaminated than the Luvuvhu River. Hence, constant monitoring of the various tributaries is recommended, and river restoration programs should be initiated where necessary.

Identifying the facts and driving factors of deceleration of groundwater table decline in Beijing during 1999–2018

Domestic water supply and agricultural irrigation are highly dependent on groundwater in Beijing. Groundwater table (GWT) decline and ecological issues caused by groundwater overexploitation have been of growing concern. However, some positive measures such as groundwater extraction control, improvement of water use efficiency, and South-to-North Water Diversion Middle Route Project (SNWDMRP) have alleviated severe groundwater shortage situation in recent years. Therefore, quantifying the contributions of different factors to the deceleration of groundwater table decline contributes to guide groundwater resources. In this study, in-situ groundwater table data, climate data, and water use data were used to identify the deceleration and driving factors of GWT decline by comprehensively using water table fluctuation (WTF) method, Mann-Kendall (MK) trend test, wavelet analysis methods, and Random Forest Regression (RFR). Firstly, the MK trend test evaluated the trend of the defined groundwater stress index (GSI) and groundwater table decline rate (GTDR) changes, indicating the fact that GWT decline was decelerated during 1999–2018. Then, the WTF method combined with in-situ groundwater level data and specific yield were used to derive the monthly groundwater storage anomalies (GWSA), which revealed a slight GWS recovery in the past decade, especially a significant increase of GWS with a rate of 5.76 mm/month since the operation of South-to-North Water Diversion Middle Route Project (SNWDMRP). Wavelet analysis identified a correlation and coherence between GWSA and precipitation in the time–frequency domain. Furthermore, correlation analysis indicated that the deceleration of GWT decline may be attributed to climatic factors (e.g., precipitation, temperature), the SNWDMRP, and water supply and use structure. The RFR quantitatively identified the greatest contribution of water use (e.g., agricultural and domestic water use) to GWT dynamics. Moreover, the effect of SNWDMRP is greater than climatic factors (e.g., precipitation, temperature). These findings have important implications for groundwater resource management in Beijing and other areas suffering from severe groundwater depletion.

Spatiotemporal changes in water consumption structure of the Yellow River Basin, China

Analyzing and summarizing the evolution law of water consumption structure and proposing corresponding control countermeasures are important for realizing the coordinated development of a regional social economy. In this study, Information entropy, Lorentz curve, Gini coefficient, and Mann-Kendall (MK) trend test were conducted to reveal the spatiotemporal variations in water use characteristics in the Yellow River Basin of China. The results showed a reduction of the dominant position of the single water consumption structure in the basin during 1998–2017, which eventually increased the equilibrium degree among water consumption sectors and made the water consumption structure more reasonable and diversified. The study identified three periods of water consumption structure transformation: 1998 to 2002 as the first growth period, and 2003 to 2012 as the adjustment period, 2013 to 2017 as the second growth period. The spatial distribution was found highly even for agricultural water consumption, while less even for industrial, domestic and ecological water use. The water consumption in agriculture was much higher compared to other sectors. The study can serve as the basis for the optimal utilization of water resources.

Evaluation of Agricultural Water Supply and Selection of Deficient Districts in Yeongsan River Basin of South Korea Considering Supply Priority

Considering the priority of water supply, agricultural water supply capacity downstream of the Yeongsan River Basin was evaluated in this study. The water balance was analyzed using the Please check all author names carefullyMODSIM-decision support system (MODSIM-DSS) to evaluate the agricultural water supply capacity. MODSIM-DSS can also be used to analyze the watershed demand status and agricultural water supply facilities. In this study, the watershed inflow and agricultural reservoir inflow (supply) data for each watershed were obtained using the SWAT outflow data. SWAT was calibrated and validated using 16-years (2005–2020) of daily streamflow data from one water level station and two weirs, by considering water withdrawal and return flows from agricultural, domestic, and industrial water use. The coefficient of determination (R2) was analyzed as 0.50 to 0.80 at three stations. Then, water balance analyses were performed for 41 years (1980–2020) by applying the SWAT outflow results to MODSIM-DSS. The results showed that agricultural water shortages of 517.8 × 106 m3, 520.0 × 106 m3, 579.8 × 106 m3, and 517.5 × 106 m3, occurred in 1992, 1994, 1995, and 2015, respectively. The efficiencies of agricultural water supply for these years were 58.2%, 58.0%, 53.2%, and 58.2%, respectively, which were lower than the 40-year average of 84.5%.

High efficiency solar steam generator comprising sodium alginate-polydopamine hydrogel for photothermal water sanitation

Photothermal distillation is an environmentally friendly water sanitation technology based on solar energy, where clean water is obtained by accelerating water evaporation through solar illumination. In this study, a sodium alginate-polydopamine hydrogel was prepared via a spreading-soaking workflow and used as a thermal evaporator. The hydrogel has well-developed pore channels, absorption above 94% for visible light and the 2.5–4 μm infrared band, an evaporation capacity of 1.40 kg·m−2·h−1, as well as good antimicrobial properties. The concentration of total dissolved solids (TDS) in the water purified with this system was approximately 16 ppm, much lower than that of tap water commonly used by families. A design is presented for a photothermal distillation system, based on this hydrogel, that can supply drinking water for domestic use. The study demonstrates the potential of hydrogel thermal evaporators for applications such as seawater desalination and wastewater treatment.