Urban Water Shortage Research Articles

Climate Variability and Water Availability in Ambositra, Amoron’i Mania Madagascar

This work provides a statistical analysis of urban water shortages, as well as the direct and indirect impacts of the scarcity of rainfall on agricultural practices in the Isaha watershed, Amoron’i Mania Region Madagascar. 78% of the urban population no longer has normal access to drinking water, and 85% of farmers report difficulties with their practices. Paradoxically, according to WEAP modelling, there is sufficient water available. Because of poorly management and other factors considerable loss of water is observed.

The impact of information provision on public willingness to use recycled water for flushing from the perspective of risk perception

To solve the current urban water shortage, increasing the willingness of urban residents to use recycled water for flushing is one proposed approach. This study developed a risk perception measurement model of recycled water for toilet flushing to explore which risk triggered people’s risk perception of recycled water, and then analyzed the interaction among information provision, trust, risk perception, and willingness to use recycled water. The main results were as follows. First, the risk perception of recycled water for flushing mainly come from four types of risks, which were performance risk, health risk, service risk and financial risk in order of importance. Second, reducing the perceived risk can improve public willingness to use recycled water for flushing, and greater trust in the water authorities and recycled water enterprises reduces the public’s perception of the risk of recycled water. A higher level of initial trust is related to higher willingness to use recycled water. Third, information provision can enhance the risk perception of recycled water and enhance trust in the water authorities and recycled water enterprises, but information provision does not directly affect the willingness to use recycled water. This indicates that reducing performance risk and health risk of recycled water, will be the key to controlling the overall risk perception of recycled water and promoting willingness to use. Effective risk communication strategies combine information provision and trust in information providers, which together affect risk perception and thus the willingness to use recycled water.

Dynamic real-time forecasting technique for reclaimed water volumes in urban river environmental management

In recent years, the utilization of wastewater recycling as an alternative water source has gained significant traction in addressing urban water shortages. Accurate prediction of wastewater quantity is paramount for effective urban river water resource management. There is an urgent need to develop advanced forecasting technologies to further enhance the accuracy and efficiency of water quantity predictions. Decomposition ensemble models have shown excellent predictive capabilities but are challenged by boundary effects when decomposing the original data sequence. To address this, a rolling forecast decomposition ensemble scheme was developed. It involves using a machine learning (ML) model for prediction and progressively integrating prediction outcomes into the original sequence using complementary ensemble empirical mode decomposition with adaptive noise (CEEMDAN). Long short-term memory (LSTM) is then applied for sub-signal prediction and ensemble. The ML-CEEMDAN-LSTM model was introduced for wastewater quantity prediction, compared with non-decomposed ML models, CEEMDAN-based LSTM models, and ML-CEEMDAN-based LSTM models. Three ML algorithms—linear regression (LR), gradient boosting regression (GBR), and LSTM—were examined, using real-time prediction data and historical monitoring data, with historical data selected using the decision tree method. The study used daily water volumes data from two reclaimed water plants, CH and WQ, in Beijing. The results indicate that (1) ML models varied in their selection of real-time factors, with LR performing best among ML models during testing; (2) the ML-CEEMDAN-LSTM model consistently outperformed ML models; (3) the ML-CEEMDAN-LSTM hybrid model performed better than the CEEMDAN-LSTM model across different seasons. This study offers a reliable and accurate approach for reclaimed water volumes forecasting, critical for effective water environment management.

China’s sponge cities alleviate urban flooding and water shortage: a review

China’s sponge cities alleviate urban flooding and water shortage: a review

Water quality variation of a typical urban landscape river replenished with reclaimed water

Replenishing landscape water with reclaimed water has been an effective way to alleviate urban water shortage. In order to investigate the variation of water quality along the pipeline and flow direction in a typical urban landscape river replenished with reclaimed water, relevant water quality indexes were consecutively monitored for 8 months. Concentrations of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) all showed a downward trend along the flow direction in reclaimed water effluent pipeline. However, values of turbidity, COD, and chlorophyll a (Chla) were decreased significantly, while concentrations of TN and TP were increased in the mixed area of reclaimed water and river. Furthermore, along Licun River, an upward trend of COD and ammonia-nitrogen (NH4+-N) was observed in summer, while in other seasons, a falling first and then rising trend of COD concentration appeared. The concentration of NH4+-N randomly fluctuated between 0.08 ​mg/L to 2.05 ​mg/L among all seasons, and TN and nitrate-nitrogen (NO3−-N) were below 15 ​mg/L with a downward first and then upward trend in each season. The concentration of TP showed a slightly upward trend (ranging from 0.08 ​mg/L to 0.57 ​mg/L) and Chla was at a relatively low level (0 – 46.32 ​μg/L). The correlation analysis revealed that light intensity, nitrogen and phosphorus were the influential factors of algae growth in river. In addition, the biomass of emergent plants and submerged plants was increased after replenishing with reclaimed water, playing a vital role in the remediation of urban landscape river.

Composition of the social urban water shortage vulnerability index (SUWSVI) applied to São José dos Campos, SP, Brazil

Mining dams within urban areas are a technological risk because, in the event of an accident, theyaffect water security. For example, a sand mining dam accident caused an interruption in the watersupply in the downstream city of São José dos Campos. Thus, the social vulnerability of the populationthat suffered from a failure in the drinking water supply was evaluated. A water shortage indicator,the Social Urban Water Shortage Vulnerability Index – SUWSVI, was composed. Variables that bestreflect the socioeconomic condition were used: Average Income of Head of Household, Female Headof Household, and Children and Elderly Dependent Ratio. The sensitivity analysis considered the cityby geographic regions and zoning classes, considering infrastructure supply and lot size. The resultsshowed that although there are full water supply and sewerage infrastructure (99.6%), the access towater was unequal (39% of the population in the medium SUWSVI range).

Decreasing water dependency for economic growth in water-scarce regions by focusing on water footprint and physical water: A case study of Xi'an, China

Rapid economic growth has led to a surge in urban water consumption, making it imperative to reduce economic dependence on water resources to achieve sustainable urban development. This study selects Xi'an as the study area and adopts the Tapio decoupling model from the perspective of the integrating water footprint (WF) and physical water (PW) to measure the state and the stability of decoupling, and the LMDI method is introduced to decompose WF and PW into five drivers. The results show that: (1) Xi'an's water efficiency increased substantially from 48.05 CNY/m3 in 2008 to 153.43 CNY/m3 in 2018, but the urban water shortage remains a serious problem. (2) Water consumption and economic growth are generally decoupled weakly and strongly; compared with PW, WF has a stronger decoupling but is less stable. Agricultural decoupling is stronger than industrial decoupling; decoupling stability is higher for industrial PW, followed by agricultural WF, and lowest for agricultural PW. (3) Technology contributes significantly to the decoupling of PW and WF, while water-use efficiency and population size inhibit the decoupling, and these factors have a more significant impact on WF than PW. The study's findings can be used to formulate effective measures to promote sustainable urban development.

Benefit of Sponge City monetization based on "water footprint theory": cases of Xi'an and Guyuan.

China has proposed to build "Sponge City" to alleviate the problems of urban waterlogging, water shortage, ecological degradation, and water pollution. The benefits of Sponge City construction have become a focus of attention because of the considerable investment and the extensive participation of all sectors of society. This paper develops a model for monetizing urban, river, and regional benefits, by taking city and river areas as the research objects. This model is based on the regional water balance, water footprint theory, and the shadow price of water. This model monetizes the potential benefits of a Sponge City before construction. Our case study is Xi'an and Guyuan. Applying the benefits calculated at the 7% discount rate, the benefit/cost (B/C) ratios of the two locations are 3.86 and 0.93 times, respectively. Also, applying the benefits calculated at the 5% discount rate, the B/C ratios of the two locations are 5.41 and 1.31 times, respectively. In terms of urban benefits, the static payback periods of Xi'an and Guyuan are about 3.7 years and 15.3 years, respectively. In terms of regional benefits, they are about 4.0 years and 16.2 years, respectively. According to the results, the return of Sponge City construction in Xi'an and Guyuan is much higher than the investment but with some risks in the investment for social investors in Guyuan. In this paper, the model and the research results can provide some references for the research on the monetization of Sponge City benefits.

The impact of climate change on population urbanization: Evidence from china

Climate change, which is mainly caused by carbon emissions, has attracted attention worldwide. With the continuous increase in temperature, the urban heat island effect, extreme weather, and water shortages have seriously affected the urbanization process. Through an empirical analysis of panel data from 28 provinces in China from 2006 to 2018, this study examines the impact of climate change-induced temperature changes on the urbanization of China’s population. The results show that the urbanization level has a significant double-threshold effect on the impact of temperature on urbanization. When the urbanization level crosses the corresponding threshold value, the negative impact of temperature on urbanization is relatively weak. Understanding the impact of climate change on urbanization has become increasingly important as climate warming increases. On the one hand, the climate issue has always been a topic of common concern around the world. On the other hand, studying how climate change affects population urbanization is conducive to identifying the human factors that affect climate change and proposing corresponding solutions. Simultaneously, it also provides a reference for optimizing the distribution of urban and rural populations, and can comprehensively consider the relationship between climate change and urbanization in the formulation and implementation of policies. On this basis, the Chinese government should strengthen financial support for climate change, play a leading role in policies, improve the urban layout and structure, and increase the resilience of cities to climate change.

Water stable isotopes reveal a complex rainfall to groundwater connectivity in central Honduras

The inter-mountainous region of central Honduras has been experiencing abrupt urban drinking water shortages during the last decade. Land use fragmentation and rainfall deficits have rapidly reduced surface water quality and quantity in this region. Here we present a 3-yr (2018–2020) tracer study within the headwaters of the Choluteca River basin (2949 km2). We sampled rainfall (weekly N = 156; daily N = 270), drilled wells (N = 166; up to ~300 m depth), boreholes (N = 70; ~4–12 m depth), and springs (N = 128) to assess the spatiotemporal connectivity between rainfall and mean groundwater recharge elevations (MREs). Clear W-shaped incursions characterized rainfall isotopic seasonality from the dry to the wet season. Air mass back trajectory analysis revealed three primary moisture sources: 73 % (east, Caribbean Sea), 17 % (southwest, Pacific Ocean), and 10 % (north; Gulf of Mexico). Groundwater sources exhibited a strong meteoric origin with evidence of secondary evaporation evolution, characterized by low d-excess values. MREs for the drilled wells ranged from 821 to 2018 m asl with a mean value of 1570 ± 150 m asl. Seasonal isotopic variability during dry-wet transitions and the influence of rapid infiltration limited the performance of the MRE method in springs and boreholes. MREs coincided primarily with coniferous forests, pasture, and crop areas, within regions of moderate to high transmissivity. These results are intended to guide the mapping and delineation of critical recharge areas in central Honduras to enhance municipal water regulations, effective environmental protection, and long-term conservation practices.

A reliable GIS-based FAHP-FTOPSIS model to prioritize urban water supply management scenarios: A case study in semi-arid climate

• Developed a GIS-based-MCDM method to select optimum urban water management scenario. • The paper considers triangular fuzzy sets to reduce uncertainty in decision-making. • The developed model is robust and flexible to manage required urban water demands. • A hydrologic model utilizing WEAP is designed to assess the developed model scenarios. The growing problem of urban water shortage and its sustainable management methods is one of today's critical research needs globally. This paper applies an integration of the Geographic Information System (GIS) and Multi-Criteria Decision-Making (MCDM) with the help of triangular fuzzy sets to manage urban water supply priorities in a semi-arid region. Hence, a group decision-making approach was proposed by combining the Fuzzy AHP (FAHP) and the Fuzzy TOPSIS (FTOPSIS) models based on quantitative and qualitative criteria. Therefore, a hierarchical model-based GIS and AHP was developed to classify the effective criteria and determine the Importance Weights (IWs) of criteria according to the experts’ opinions and using data layers based on spatial criteria. The priority ranking of scenarios was obtained using the FTOPSIS method. Different criteria such as environmental, geographical, geological, economic, climatic, and social conditions were considered in this study. Furthermore, to assess the water supply scenarios under the essential water demands of the basin cities and suburbs, a hydrologic model utilizing WEAP software was designed. Among the considered criteria, total expense, climatic conditions, and geographic conditions with the IWs values of 0.9, 0.85, and 0.83 were determined as the most effective criteria for evaluating the scenarios' ranking, respectively.

The Gap between Willingness and Behavior: The Use of Recycled Water for Toilet Flushing in Beijing, China

Promoting the use of recycled water is an effective way to solve the problem of urban water shortage. In order to promote the utilization of recycled water, this study identified the influential factors determining the differences between willingness and behavior to use recycled water for toilet flushing. Binary logistic regression models of willingness and behavior were analyzed and the data came from 1195 Beijing residents in communities where recycled water was available for toilet flushing. The results are as follows: First, the proportion of those willing to use recycled water (92%) was significantly higher than those who actually did so (35.2%); thus, higher willingness to use recycled water did not necessarily lead to higher using behavior. Second, different factors influenced willingness and behavior, with the willingness mainly influenced by cognitive and attitudinal factors, and the behavior dependent on external environmental factors such as the convenience of installation and promotion measures. Third, the convenience of the installation of recycled water facilities is the most important factor influencing both willingness and behavior, and inconvenient facilities are the main factor hindering the use of recycled water.

Dynamic Relationship of Urban and Rural Water Shortage Risks Based on the Economy–Society–Environment Perspective

Based on the economy–society–environment perspective, this study details the causes and characteristics of urban and rural water shortage risks, and then explores the dynamic relationship between urban and rural water shortage risks. It quantitatively analyzes the urban and rural water shortage risks of 52 areas in Northwest China during 2001–2019. Furthermore, the dynamic relationships are tested by using the exploratory spatial data analysis model. The main conclusions are as follows: (1) The water shortage risk level is gradually declining over time, while the urban water shortage risk is improving faster than the rural water shortage risk. (2) The relationships show significant synergy. There are four primary types: strong synergy areas, medium synergy areas, weak synergy areas, and very weak synergy areas. (3) The levels of synergy within the northwestern regions show a positive spatial correlation and spatial agglomeration; that is, regions with high levels of synergy are adjacent, while regions with low levels of synergy are adjacent. From the perspective of local spatial differentiation, positive spatial autocorrelation patterns (H-H and L-L) account for a large proportion and gradually increase over the research period, reflecting the patterns of H-H and L-L. The agglomeration becomes increasingly obvious.

Construction of evaluation index system of reclaimed water development and utilization potential based on AHP

The shortage of water resources has severely restricted the rapid development of modern cities in China, and the recycling of reclaimed water is one of the important methods to effectively solve the bottleneck problem of urban water shortages. Based on the Analytic Hierarchy Process (AHP), this study determines the evaluation indexes and their weights from social and technical levels respectively and constructs an evaluation index system of reclaimed water development and utilization potential, which contains 3 levels, 5 criteria and 19 alternatives, focusing on the production, utilization and benefit of reclaimed water and other characteristic indexes. From the weighting results of the index system, among the main influencing factors of reclaimed water development and utilization, the water quantity factor has the greatest influence, the influence of water usage and water quality assurance ranks second, and the economic factor has the least influence. This evaluation system provides a useful reference for the reasonable development and utilization of regional reclaimed water in the future.

Restoration of Urban Water Environment Landscape System and SWMM Technology Integration in Water-Scarce Cities

Economic development has led to a rapid increase in urban water consumption. The number of cities with water shortages nationwide is increasing. The establishment of a water resource circulation system is conducive to solving the urban water shortage. This study aims to investigate the restoration of the urban water environment landscape system and the integration of SWMM technology in cities with scarce water resources. For this objective, the meteorological situation of a city with water shortage in central China was used to establish the surface water hydrological model of Teaneck Creek. By establishing a data collection system at each meteorological point of the city, the USEPA SWMM model was implemented to simulate the movement of the urban sub-base system. The relationship model between the surface water flow and groundwater flow was established, and then the relationship between vegetation and soil was determined to formulate a plan for the restoration of a benign and environmentally friendly urban water environment landscape system. The established model can solve the urban water shortage problem. The results showed that the developed model was increased the utilization rate of water resources by about 20% and the urban greening rate by about 15%. The system will bring China a sustainable and eco-friendly urbanization process, which is of guiding significance for the production and development of cities with water shortages in China.

Conflict or consensus? Stakeholders' willingness to participate in China's Sponge City program

In 2015, China initiated the Sponge City Program (SCP), an integrated urban stormwater management strategy, to mitigate the paradoxical challenges of urban flooding and water shortages. Very few studies have attempted to examine the willingness to participate of multi-level stakeholders in the case of storm-water management initiatives. To address this gap in the existing body of knowledge, this study took Guyuan city, Ningxia Province, a Stage 2 pilot city located in the arid northwest region of the People's Republic of China, as a case study. Members of three key stakeholder groups were surveyed, i.e., government, commercial entities and communities, and a total of 687 valid questionnaires were obtained in the SCP. Via a logistic regression model, the results showed that: (1) the stakeholders reached a consensus during the participation process that they were motivated by personal benefits and expected to improve water usage through the participatory process; (2) the government represented the public interest by prioritizing the overall improvement of the urban water environment and improving standards of living by contributing to the program; (3) the commercial entities prioritized the acquisition of knowledge and technical issues relevant to their business operations, and expressed concerns about how these operations might be affected by stakeholder participation; (4) both the commercial and community groups were more willing to participate if they perceived that the SCP would affect their daily lives, and the general public were willing to participate for multiple reasons. This study will help to guide future studies to continuously explore the diverse factors that influence the stakeholder participation of diverse stakeholders. The findings can also benefit the design of future projects with a view to enhancing stakeholder participation. Recognizing the quantifiable benefits of the SCP, this paper demonstrates how the evaluation of diverse stakeholders' priorities and the assessment of the drivers for their willingness to participate can further benefit the implementation of sustainable urban water initiatives, as in the case of this megaproject, and their enduring success.

An inexact multi-stage interval-parameter partial information programming model for water resources management under uncertainties

Abstract The urban water shortage crisis around the world is increasing. In this study, an inexact multi-stage interval-parameter partial information programming model (IMIPM) is proposed for urban water resources planning and management under uncertainties. Optimization techniques of two-stage stochastic programming (TSP), interval-parameter programming (IPP), linear partial information theory (LPI) and multistage stochastic programming (MSP) are combined into one general framework. IMIPM is used to tackle uncertainties like interval numbers, water inflow probabilities expressed as linear partial information, dynamic features in a long planning time and joint probabilities in water resources management. It is applied to Harbin where the manager needs to allocate water from multi-water sources to multi-water users during multi-planning time periods. Four water flow probability scenarios are obtained, which are associated with uncertainties of urban rainfall information. The results show that the dynamics features and uncertainties of system parameters (such as water allocation targets and shortage) are considered in this model by generating a set of representative scenarios within a multistage context. The results also imply that IMIPM can truly reflect the actual urban water resources management situation, and provide managers with decision-making space and technical support to promote the sustainable development of economics and the ecological environment in cities.

Spatial and temporal analyses of potential land use conflict under the constraints of water resources in the middle reaches of the Heihe River

With the rapid urbanization in China, land resources are becoming increasingly scarce. Identifying and resolving land use conflict is essential for reasonably using land resources and achieving land sustainability. Taking the middle reaches of the Heihe River as an example, we included the constraints of local water resources to construct a multi-criteria evaluation system for assessing land use competitiveness in 2000 and 2015 based on land use, socio-economic, and nighttime light data. By comparing the competitiveness of cultivated land, construction land and ecological land, we then derived the spatiotemporal patterns of potential land use conflicts. Actual land use changes supported the hypothesis that land use tended to convert into the type with higher competitiveness at areas with intense conflict, which better indicated that our assessment model was effective. The results showed that the potential land use conflict was more acute in the central and northwest but weak in the southeast and northeast, and its pattern showed a significantly positive spatial autocorrelation. The conflict between cultivated land and construction land was most prominent and mainly occurred in the transitional zone from urban to rural areas. Rapid urban development and water shortage were the main causes of the potential land use conflict. Assessing land use multi-functions and making a tradeoff among ecological, economic, and social services will be an effective way to guide future land use to solve land use conflict. Our research provides scientific evidence for sustainable land use planning and management in the arid areas.

Computation fluid dynamics model of first-flush runoff through a hydrodynamic separator

Abstract Urban rainwater harvesting systems are widely used to solve urban water shortage. However, the initial rainwater collected from urban roads contains numerous particles that severely limit its reuse. This study designed a hydrodynamic separator on a separated sewer systems (between the rainwater collecting main pipe and intercepting main canal) to remove particulate pollutants, avoid rainwater reflux, and realize staggered regulation during flood peak. In this work, a 3D model of the hydrodynamic separator was constructed using SolidWorks software, and state-of-the-art FLUENT computational fluid dynamics was applied in fine-scale simulation of the hydrodynamic separator under complex initial conditions. Numerical tests were performed to validate the capability of the hydrodynamic separator in removing particulate pollutants under different initial conditions. The results of numerical tests showed that particle trajectories are relatively regular spirals in the hydrodynamic separator, whereas large-diameter particles feature high removal rates. Particle removal rate increased with increasing diameter-depth ratio and height difference between the overflow and inlet pipes. Considering the particle removal rate, the optimal order of angles between the overflow and inlet pipes is 90° > 150° > 60° > 120°. The parameters of the hydrodynamic separator in removing initial rainfall particulate pollutants were obtained, and a pilot-scale experiment was conducted, providing theoretical importance in reducing energy consumption of rainwater harvesting pretreatment systems.

Implementation of the “sponge city” development plan in China: An evaluation of public willingness to pay for the life-cycle maintenance of its facilities

Urban stream syndrome, including urban waterlogging, flood risk, water shortage, water pollution and ecological restoration, are major challenges that cause potential risks to human beings. Recently, the sponge city construction (SCC) initiative in China has received extensive attention because it aims to systematically solve all of these urban water-related issues for a city. To date, little research has focused on the life-cycle operations, maintenance requirements and low public awareness of sponge city facilities (SCFs; e.g., rain gardens, green roofs, grass swales, and pavement greenbelts), which are challenges facing the development and sustainability of the SCC initiative. The aim of this study is to explore (i) the willingness to pay (WTP) for the life-cycle maintenance of SCFs and its determinants and (ii) the public's perceptions and attitudes towards the SCC initiative. We conducted a questionnaire-based survey combined with contingent valuation in three pilot sponge cities and then applied a two-phase logistic model and Tobit model to estimate the WTP of the respondents and the factors influencing the WTP. The results show that 76% of the respondents agreed to pay for life-cycle maintenance of SCFs, and the median amount of WTP was 16.57 CNY (2.53 USD) per month. Important factors influencing WTP include respondents' perceptions of the efficacy of the SCFs, concerns regarding the waterlogging risk and support for the SCF construction plans. The findings of this research extend our knowledge of the public's perceptions of and attitudes towards the SCC initiative and suggest that public contributions could serve as a crucial and feasible funding source for the life-cycle maintenance of SCFs.