Abstract

This research is about how farmers adapt to water scarcity. Using experimental economics methods, field experiments were carried out in a region exposed to severe water scarcity in Colombia. Willingness of water users to cooperate in conforming to extraction caps, as a means of adapting to water availability declination was calculated. Two information treatment groups were implemented in order to assess water allocation decisions when: (i) the amount of water was reduced and (ii) time before aquifer exhaustion was announced. Extant literature on cooperation in common-pool resources (CPR) has focused on demonstrating to what extent resource users depart from egoistic attitudes. Alternatively, the sustainability of water resources requires more research to further understand cooperative behavior. Since the literature on water scarcity is classified in three orders, namely physical, institutional, and socio-political, behavioral dimensions are suggested as a subdivision of the social order. This, in turn, may help to operationalize strategies aimed at improving adaptation to all orders of scarcity. The quantitative results suggest that farmers are inclined to follow the cap. The main difference between the quantity and time treatments differs in that in the time treatments farmers allocate much more water to be consumed in the future, whereas in the former, they prefer to allocate more water to be consumed in the present. Adaptation options provide favorable inputs for implementing the Sustainable Development Goals, especially SDG 6, which is related to water use efficiency. Target 6.4 establishes that, by 2030, water efficiency and extraction sustainability should be accomplished. Thus, water policy interventions might benefit from this contribution. However, since success in water conservation programs might be difficult to achieve due to complexity in human-decision making, more research is needed to deepen our understanding of cooperation drivers in aquifer conservation.

Introduction

Despite the abundance and precision of current information on aquifers status ( van der Gun, 2022 ), this type of data – commonly managed by governmental institutions – rarely flows to the communities that depend upon them ( Margat & van der Gun, 2013 ). In effect, underground water availability data is currently assessed through satellite and underground monitoring of aquifer levels, but farmers´ communities do not have access to this information in a format they can readily use. Climate change is entering the aquifer overexploitation game as a new player ( Damania et al., 2017 ), since droughts are becoming more frequent than in the past ( UNWATER, 2023; Yuan et al., 2023 ); therefore, public environmental and water entities promote water conservation during droughts. Public entities usually stimulate the reduction of water extraction volumes by instructing users to consume less or save the resource. This information, however, lacks the necessary context and specificity, two features that play an important role in water extraction curbing adapted to ensuing water scarcity.

Although water scarcity has an important political dimension ( Metha, 2007 ), from the perspective of its physical and social dimensions, it can be observed how climate change is motivating farmers towards strategies to face the challenge. In spite of the complexity of hydrogeological information, farmers certainly want to know more about the status of the aquifers they are exploiting. They need information not only about the effects of their extraction decisions, but also about the way to moderate these decisions as an adaptation to scarcity according to aquifers’ statuses.

Conclusions

This article was designed for presenting the results on how farmers adapt to water scarcity. Framed field experiments were run to collect quantitative data on the decisions made by farmers when they were exposed to reductions in water availability. Time and water quantity treatment groups were prepared to test their effects on water allocation as limited by suggested extraction caps. Quantitative and qualitative analysis of data and information were carried out. Behavioral regularities and social institutions were drawn from the quantitative data and graphics and the narratives expressed by the players after the experiments.

The setting for the understanding of adaptation strategies was demarcated by the limits imposed by nature. For this reason, water availability as a physical limiting factor for water extraction was used as an instrument to connect allocation, decision-making and intertemporal consequences for adaptation. Thus, limited availability under time and quantity limits pushed the farmers (players) to decide whether to cooperate or not in water conservation. Thus, the individuals who cooperated better were adapting to water scarcity. More precisely, the farmers informed on time before aquifer exhaustion, revealed greater awareness about the possibilities of cooperation. Contrarily, in the control group situation, farmers allocated much more water to all uses and the cap volume was reached in most of the rounds. While in the time and quantity treatment groups, the aggregated water volumes declined through the time (rounds), in the control group this amount averaged 1800 m3 (close to the cap). It can be said that the communication amongst farmers on how to manage remaining stocks, and, similarly the hydrogeological information play a key role in incentivizing the cooperative behavior under extraction caps contexts. Since the stability of cooperation was part of the research aims, providing quantitative information to farmers on extraction decisions and the remaining time of aquifer availability is suggested as a key factor to more effectively address the adaptation to water scarcity.

Abstract

Significant population growth with rapid economic development have led to water scarcity problems around the world. Currently, most of the simple water scarcity assessment methods only refer to per capita water use, failing to take into account actual water availability and actual human domestic water use. Therefore, we have developed a simple and practical method to assess water scarcity, incorporating total water resources, water use efficiency, and the proportion of domestic water. In this approach, a new water scarcity index is employed to describe different levels of water scarcity using various thresholds based on the basic daily human water use per person. This may help to visualize the extent of water scarcity in a region while focusing on human interests. To illustrate this approach, we take China–the world’s largest developing country–as an example, analysing its nationwide water scarcity in 2021 while validating it with the results of other scholars on China’s water scarcity. The results show that our water scarcity assessment index is very accurate, revealing that in 2021, the disparity in water resources between the northern and southern regions of China remains substantial, with severe water scarcity still widely concentrated in northern China.

Introduction

Continuous water supply plays a vital role in daily life and social development ( Ethaib et al., 2022 ). However, increasing water consumption is due to the significant population growth and rapid economic development, resulting in extremely high water resource pressures, which cause water scarcity in numerous places around the world ( Liu et al., 2017 ). For instance, in regions such as Greater London with high population density, intense irrigation present in areas like the High Plains of the United States, and nations like India that exhibit both traits, there is a prevalent issue of water scarcity ( Mekonnen and Hoekstra, 2016 ). Nevertheless, in addition to direct water supply shortages caused by the forces of nature, human factors, as well as socio-political factors, are often overlooked, leading to the masking of the causes of scarcity. This complexity of water scarcity is labelled by Mehta as ‘real’ scarcity (related to socially and ecologically relevant physical phenomena like grass cover, fodder, distance to water for disadvantaged groups, cycles of natural resource abundance and scarcity, agro-meteorological hydrology, etc.) and ‘manufactured’ scarcity (constructing water scarcity as a perpetual and pervasive natural phenomenon, the industry of disaster relief and drought relief, and perverse benefits) ( Mehta, 2003 ). Moreover, there are also sudden and uncontrolled factors affecting water resources, such as the outbreak of the COVID-19 pandemic crisis, which has put many additional pressures on water resources, including the increase in local agricultural irrigation brought about by the localised production of food, and the parallel alteration of the virtual water trade caused by the changes that have taken place in the food trade ( Al-Saidi and Hussein, 2021 ).

Results

3.1. Statistical analysis of the results

A comparison of the water scarcity index calculated using Eq. (1) for each region of China, with a threshold of 0.2 (no stress), is shown in Fig. 2 . The results show that most regions in China are still suffering from water problems, including some economically developed cities with heavy water problems, such as Beijing (0.01), Tianjin (0.008), and Shanghai (0.02). In contrast, Qinghai (1.43) and Xizang (10.56) have abundant water resources, which are significantly higher than in other regions.

3.2. Spatial analysis of the results

In this study, ArcGIS Pro software was used to raster water resource data from various provinces in China in order to comprehensively and visually assess water scarcity across the country. As can be seen in Fig. 3 , the water scarcity index shows obvious spatial distribution differences, mainly between the northern and southern regions of China. Overall, the water scarcity index shows absolute scarcity in the north and no stress in the south. Specifically, a wide range of areas in northern China, including Inner Mongolia, Liaoning, and Shaanxi, exhibit water scarcity and some pressure on water resources. It is worth noting that some areas in the north also show absolute water scarcity, especially in Beijing, Tianjin, Hebei and Shanxi, indicating that the available water resources in these regions do not meet the minimum basic human needs of the region.

Highlights

Abstract

Keywords

1. Introduction

2. Materials and methods

3. Results

4. Discussion

5. Conclusion

CRediT

Declaration of competing interest

Acknowledgements

Appendix A. Supplementary data

References

Abstract

Amongst different climatic and anthropogenic drivers, water resources management can cause massive changes to the natural regime of a lake after its regulation, thereby affecting the quantity and quality of water intended for satisfying the multiple basin water requirements. Here, we investigate the multi-decadal variation of the water levels and outflows of Lake Garda, the largest in Italy, where the dam operational rules and the related basin water needs heavily altered the annual and seasonal trend of the lake regime since its regulation in 1951. Daily lake levels and outflows were first collected and digitized for the period 1888–2020, thus providing a unique database of 133 years that allowed a consistent comparison between natural and regulated periods. Statistical analyses highlighted a significant change of the inter-annual trend of the lake outflows, which passed from upward to downward after regulation, against a constant increasing trend of the water levels. Conversely, water levels showed a more remarkable shifts on a seasonal scale if compared to the outflows, revealing the influence of summer and winter basin water needs. Additional analyses on the inter-annual variation of the main downstream water demands regulated by the dam, i.e. the irrigation, hydropower and fluvial ecosystem requirements, outlined their relevance in changing the lake regime, influencing dam operational policies, which progressively limited the share of water released for ecosystem integrity. A comparison between the lake levels and outflows recorded for the pre-regulation and post-regulation periods of some selected European perialpine lakes finally highlighted different effects on the lake regime, drawing attention to the importance of defining the role of the dam operational policies within the current scenario of climate change and changing water demands.

1. Introduction

Lakes are one of the major global sources of renewable freshwater (Gleick, 1993), and they have been massively turned into regulated systems since the second half of the XX century (World Commission on Dams, 2000; Gleick, 2003). Despite the potentially high amount of water that can be allocated through lake regulation, efficient management of lake levels and outflows is an increasingly critical issue. Major water demands, like hydroelectricity production (Zarfl et al., 2015) and crop irrigation (Oki and Kanae, 2006), long-standing water interests, e.g. navigation and touristic activities, together with climate change and the need to ensure decent environmental standards for freshwater bodies (European Commission, 2000), challenge the way we manage key lake regulation systems, such as dams, to optimally benefit the human society and the natural environment (Moore et al., 2010). Dam construction, even on previously existing natural lakes, indeed determines relevant alterations both on the downstream riverine system and on the lake itself, affecting a variety of hydrological, geochemical and biological aspects (Ward et al., 1983; Nilsson et al., 2005; Magilligan and Nislow, 2005; Poikane et al., 2020).

Abstract

1 Introduction

2 Materials and methods

3 Notation and Defnitions

4 Study area

5 Results and discussion

6 Conclusion

References

Abstract

     This paper proposes a new framework to optimize the allocation of water resources considering two perspectives of water value and strategic management which is one of the novelties of this study. After identifying agricultural, industrial, and domestic water demands, a water allocation model is developed to maximize the net benefit of water delivered to each sector. Based on the characteristics of the study area which is the Namak Lake basin, water transfer from Dez tributaries can be considered as an uncertainty depending on the climate and political issues. So, the model is initially performed without considering water transfer and then water transfer is considered to enhance the flexibility. In addition, the initial model does not assign the weights to the plain. In the novel model, weights derived from questionnaires are applied to reflect experts’ opinions and consider the priorities of the plains. Transferred water is then allocated from the strategic management perspective and the water value perspective (six possible combinations of perspectives and scenarios), and eleven independent variables are considered in the model. Also, GMCR + , the new version of the Graph Model for Conflict Resolution, is applied to visualize the possible scenarios and equilibrium states based on the status quo of the conflict. Based on the results, the first scenario of water value perspective is chosen which results in a significant water allocation to the industry and agriculture sectors (approximately 94% and 96%, respectively). Also, 94.6% of potable water is satisfied compared to the initial water needs.

Introduction

     Nowadays, water allocation is a major problem in water resources planning and management considering water limitation and scarcity, population growth, agriculture and industrial uses, and food security (Dinar et al., 1997). There are many goals, stakeholders, and researchers are trying to improve allocation criteria. Among these criteria, economic issues are important parts in which researchers beneft from multi-objective optimization to deal with the problem (Guo et al., 2014; Roozbahani et al., 2015). In addition, water demand varies per nation due to variations in hydrological parameters (Wang et  al., 2016). For example, climate change has raised certain plants and animals’ water needs. Economic growth and decreasing precipitation have limited human water availability (Yao et  al., 2019). So, water scarcity problems arise as demand for water hits the limits of fnite supply. Water allocation especially in water transfer projects implemented to overcome such a crisis often results in water conficts among water users and stakeholders. Therefore, confict resolution is an essential component of water resource management, particularly in the case of water transfer systems, and various quantitative and qualitative methods have been proposed for it. Game theory provides a framework for studying the strategic actions of individual decision-makers to develop more broadly acceptable solutions to confict resolution (Madani, 2010).

Conclusion

     According to the high costs of fulflling the water needs of the province and transferring water from the Dez branch to this province, the purpose of this study was to optimize the allocation of water resources to diferent sectors to maximize the proft from water allocation. The optimization model performed with and without considering the water transfer and taking into account the priority of users from the strategic management and water value perspectives. Without considering water transfer due to fewer constraints and non-prioritization of uses, the overall amount of water is higher, but in the other two states having more constraints and allocating some water to the aquifer recharge, its value has reduced to half.

     The amount of water allocated to the plains other than Sharifaabad plain has decreased by assigning weights to the model. Water allocated to the drinking and industrial sectors has increased due to water transfer. It is clear from the results of the confict analysis that according to the conditions, all sectors choose the water value-frst scenario. By implementing this scenario a signifcant allocation has been made to industry and agriculture, and 94.6% to the drinking sector. It should be noted that the drinking sector plays a more important role than other sectors, and it is necessary to satisfy drinking water needs. Finally, to compare the results of this study with the real situation of the study area in 2021, statistical data show that total precipitation is less than in the past years and total discharge has been decreased. So, based on the slope of the total discharge line in Fig. 4, it could comply with the estimation.

The aim of this study is to assess the water quality of Lower Jhelum Canal (LJC) and its suitability for irrigation purposes. An effort has been made to develop a method by integrating water quality index with geographic information system (GIS) for an effective interpretation of LJC water quality. The pollution status of LJC was estimated by different physicochemical and biological parameters. Based on results of analysis, a spatial distribution map of selected water quality parameters was prepared using GIS. An inverse distance weighting (IDW), which is an interpolation technique, was applied to prepare a thematic layer of parameters at each station of Lower Jhelum canal. The results of individual parameters showed that the concentrations of contamination were within permissible limits of WHO and NEQS guidelines except for E. coli. Overall, most of the water falls in excellent quality category indicating the suitability of water for irrigation purpose. The results suggest that most of the water can be used for irrigation and various intended purposes except direct use of water for potable or drinking purposes without treatment.

Introduction

Water is the most significant ingredient for supporting and evolution of life (Kuutondokwa, 2008). Humans get different sorts of benefits from freshwater, which includes water for drinking, industrialization, domestic uses, irrigation, for the production of waterfowl and fisheries, use for leisure, shipping, and waste discarding (Jackson et al., 2001). Water is a source of economic gain. Almost 70% of water is used in agricultural production, which is indirectly the cause of economic growth (Brown and Matlock, 2011). Water resources (Freshwater) are becoming limited for individuals due to overpopulation, so the accessibility of freshwater for human beings decreases (Iqbal et al., 2018). Quality of freshwater deteriorates by developmental activities that contaminate the water bodies, their effects on human health, ecosystem disturbance and issues related to its management and monitoring (Iqbal et al., 2019). Water quality deterioration is the primary threat to public health at the global level (Rahman et al., 2020). Anthropogenic actions, like improper disposal of municipal, industrialized effluents, and unsystematic use of chemicals in agriculture, are vital aspects causative in the worsening of water quality (Azizullah et al., 2011; Iqbal et al., 2020; Subedi et al., 2019; Shirani et al., 2018; Li et al., 2020). The result of these activities is eutrophication, loss of water quality, loss of biodiversity, effects on human health and social security, deposition of nutrients and other inorganic pollutants, acidification and significant economic losses (Kraemer et al., 2001). Contamination of water leads to water scarcity or it may be polluted at that level where it is expensive to treat (Gupta et al., 2012; Maged et al., 2020; Imran et al., 2020). Consequences of both water treatment and water scarcity with high cost would be the reason for the increase in water prices (Kuutondokwa, 2008). According to (Rogers et al., 2002), water is an efficient good. However, the nations which have water resources could grow their economies, while on the other hand, it will be difficult for poor or developing countries, even to avail of their essential needs.

Flood risk is generally composed of two parts: the probability of happening a hazardous event and its consequences. The first part is the source of risk and it is mainly given by the flooding magnitudes, although flow velocities and flooding permanence may play important roles. The second one reflects the vulnerability of the socioeconomic system exposed to flooding. Three aspects can represent vulnerability: exposure, susceptibility and value. Additionally, resilience can work to diminish vulnerability, incorporating the system responsive capacity. However, it is usual that risk assessment considers only the direct damage of flooding, tending to prioritize areas with high potential losses using an economic-based approach. This approach can exclude socioeconomically vulnerable communities from receiving proper attention and consequent investments in flooding mitigation measures. In this context, this paper presents an index to measure the Socioeconomic Recovery Capacity of urban areas prone to flooding through a multi-criteria approach, contributing to knowledge by introducing a social bias into flood risk discussion. The Flood Risk to Socioeconomic Recovery Capacity Index (Ri-SoRCI) considers the relative potential damage of flooding events, based on the capacity of the affected inhabitants to recover from losses. The Ri-SoRCI represents a socioeconomic parcel of the flood risk, through two indicators. The first represents the economic recovery capacity of an impacted region. The second indicates the region’s social vulnerability. The Ri-SoRCI was applied to the Canal do Mangue basin, in Rio de Janeiro, Brazil, supported by an environmental modeling tool able to simulate flooding phenomena with an integrated approach. The result shows the risk variation for different areas, from the socioeconomic point of view, subsidizing decision-making for public investments and allowing the construction of sustainability indicators to assess multiple scenarios. The case study validated the proposed index.

INTRODUCTION

The urban population of the world has been growing rapidly over the last years, having increased from 30% in 1950 to 55% in 2018. By 2050, the world’s population residing in urban areas is projected to be 68% (DESA/UN-WUP, 2018). The current number of people at risk from flooding is about 1.2 billion and, by 2050, this number rises to 1.6 billion, nearly 20% of the world’s population (WWAP/UN-Water, 2018). Urbanization associated with changes in land cover results in significant increase of impervious areas and decrease in vegetated surfaces, heavily modifying the characteristics of the surface runoff (Goonetilleke et al., 2005), increasing peak flows and stormwater volumes (Barbosa et al., 2012). Such effects associated with a forecasted increase in the precipitation intensity, caused by global climate change (Meehl et al., 2007), can intensify the stress on drainage infrastructures and increase flood hazards (Hoegh-Guldberg et al., 2018), expanding flood prone areas (PetitBoix et al., 2017). The increased flood risk encountered in today’s cities is mainly related to changes in land use and to the intense process of urbanization (Gogate et al., 2017).

Identifying objectives is essential for decision making, but individuals have difficulties stating their important objectives. In public and environmental decisions, the diverse views of stakeholders should be included, but eliciting a broad set of objectives is challenging. We (1) study the effectiveness of individual brainstorming for eliciting objectives in a real-world setting; (2) test three interventions to support individuals in generating objectives; (3) investigate which and how many stakeholders are necessary to generate a comprehensive set of objectives; and (4) develop a feasible elicitation procedure for practice. In an experimental test, 71 stakeholders participated in five decisions about regional wastewater infrastructure planning in Switzerland. Three interventions were tested with an online survey procedure: (i) providing category cues, (ii) a perspective-taking task, and (iii) providing a predefined master list of objectives. In simple brainstorming, participants stated few objectives (M = 3.3) associated with 2.9 different categories on average. Participants consistently missed objectives they later considered important. Providing a master list was the only intervention that substantially increased the number and breadth of objectives (M = 12 objectives in M = 5.3 categories). With the help of our survey, participants generated between 30 and 38 distinct objectives for each decision case. Between five and nine participants were sufficient to generate these; more participants did not contribute new objectives. Most decision makers need help generating their objectives; combining simple brainstorming with a master list is a straightforward improvement that does not require a facilitator. An online process is promising for involving a large group of stakeholders.

Introduction

Knowledge about objectives is decisive for any analytical decision-making effort (e.g. Keeney, 1992). In a rational decision, the selection of an alternative is based on its achievement of objectives. Thus, in procedures such as multi-criteria decision analysis (MCDA), identifying objectives at the beginning is key (Gregory et al., 2012; Keeney, 1992; Reichert, Langhans, Lienert, & Schuwirth, 2015). As the objectives define the content of the evaluation, analysis, and discussion of alternatives, different sets of objectives can lead to different decisions (Brownlow & Watson, 1987). The omission of objectives, perhaps due to an oversimplified problem representation, can bias the analysis (Montibeller & von Winterfeldt, 2015; Payne, Bettman, & Schkade, 1999). Therefore, the set of objectives should be generated carefully. However, in actual decisions objectives are often not identified at all, or only cursorily (e.g. Gregory et al., 2012). For public and environmental decisions, the identification of objectives is both particularly relevant and particularly difficult. The normative demand is that these decisions serve the public interest. Objectives can be an appropriate level at which to operationalize this concept and formulate an integrated perspective on these decisions. Often, a few individuals take these decisions on behalf of a much larger group of stakeholders. However, how we can support these representatives in generating a set of objectives that addresses a wide range of concerns is an open question. It is also unclear how the public can be directly involved in this process. At first glance, the task of identifying objectives appears trivial: we just ask the decision makers to list what they want. However, the process of eliciting and structuring objectives is often considered “more of an art than a science” (Keeney, 1988). Bond, Carlson, and Keeney (2008, 2010) have found that individual decision makers are unable to fully articulate their objectives and without additional support neglect objectives they actually consider important.

A water price increase has been used as an effective method to guarantee national water security and maintain national food security in China. The reasonableness of the water price has a direct influence on people’s attitude, behavioural decision regarding willingness to pay, and motivation for water conservation. A double-bounded dichotomous choice contingent valuation method was used to assess the impact of integrated agricultural water price reform on farmers’ willingness to pay for irrigation water in northwest China. The estimated mean willingness to pay in the study area was 0.144 RMB/m3 . A comparison showed that higher education and longer experience in farming were likely to result in a higher willingness to pay in the study area. Participants who had a higher awareness of water price reform showed a higher likelihood of agreeing to higher bidding. Those who thought the current water price was lower had a higher willingness to pay for irrigation water. Participants who considered agricultural water resources to be scarce in the area also had a higher willingness to pay. In contrast, the bidding variables were negative and significant at the 1% level, showing that participants were more inclined to reject a higher bid. Meanwhile, the older the participant, the less they were willing to pay. An unintended finding was that participants’ willingness to pay decreased if they chose to use water-saving technology. One possible explanation was that the investment in the construction of the infrastructure (such as pipes and pumps) may have exacerbated farmers’ burden and may not have resulted in any benefits to them. Based on the results of this paper, a related optimization policy was presented for water price reform.

Introduction

Water scarcity is increasingly becoming an issue both in developed and developing countries and is hindering social and economic development worldwide, particularly in semi-arid areas (Feng et al., 2017). Climate change has disrupted previously stable cycles of snow, rain and storms, resulting in an unpredictable natural supply of water, and the relative speed of the transition to such unstable global water conditions has surprised governments and companies alike (Schaefer et al., 2019). A recent study showed that there are at least more than 800 million people lacking a safe supply of freshwater and 500 million people are increasingly near this situation throughout the world (Cheng et al., 2019). The emerging water crisis is becoming among the most serious problems facing humans in the 21 st century (Zhao et al., 2017) throughout the world. As the largest developing country in the world, China’s situation in many respects exemplifies the global picture, particularly water scarcity in northern part of the country (Wu et al., 2015). The water resources per capita is less than a quarter of the world’s average, and water shortage in northwest China is more serious than that in other regions. As in many developing countries, irrigation has played an unsurpassed role in the sustained growth of Chinese crop production in China (Shen and Lin, 2017). Irrigation in regions of limited rainfall in northwest China dominates water use, often accounting for greater than 60% of total water use (MWR, 2015). However, with the growth of the global population and the demand for food, as well as competition between different water sectors, the pressure on irrigation systems to act as major consumers to release water for other uses and improve performance in these areas has increased (Sun et al., 2016).

This work elaborated an analysis of urban water metabolic system. The system’s flows and processes were modeled and accounted on the basis of the ecosystem cumulative energy availability, also known as emergy. In detail, both the urban domestic water supplying process metabolism model and accounting framework were defined. Then, the whole process of the supplying of domestic water was analyzed, considering Beijing (China) as a case study. In particular, the existing water sources were included: surface water, underground water, water of the South-to-North Water Transfer Project; potential desalinated water from Tianjin. The results showed that, for the supply of 1 m3 of tap water, the total emergy input from the above-mentioned four sources are 3.22Eþ12, 3.34Eþ12, 4.55Eþ12, and 12.55Eþ12 sej. These values reflect the different energy costs of the existing supply systems, that are related to water transportation, treatment and distribution, Moreover, the emergy cost of desalinated water is about 4 times higher than the one of surface water. Conversely, the value of South-to-North Water Transfer Project is not much higher than that of surface water. Finally, the higher costs are related to the water treatment phase. Consequently, some policy recommendations and future research directions are identified for improving the sustainability for Beijing domestic water supply.

Introduction

Finite water resources, increasing demands and aging water infrastructures are some of the greatest challenges for China and many other regions of the world. The rapid increase in water demand and the reduction of the fresh water supply, resulting in water shortages, are now a serious problem in many countries (Wang et al., 2016). The United Nations Educational, Scientific, and Cultural Organization (UNESCO) predicts that global water demand will increase by 44% in 2050, with residential water growing nearly 1.5-fold (UNESCO, 2014). Without a constant supply of water, human society cannot smoothly and continuously develop (Chen et al., 2016). Urban areas are especially vulnerable to these problems, due to their higher population density. This is why, nowadays, an accurate planning for a sustainable use of water resources is of paramount importance. With this respect, complex water issues cannot be solved applying a chambered water management approach, especially at the urban scale. For example, Hu et al. (2013) showed that the majority of the present water consumption in Beijing was due to family use, i.e., domestic water. Before the operation of the South-North Water Transfer Project (SNWTP) in 2014, Beijing’s water mainly came from the local surface water and groundwater. However, this limited supply couldn’t meet the growing demands. As an “alternative source” of traditional surface water and groundwater, SNWTP greatly alleviated the pressures on the Beijing water supply. In a water-connected world, sustainable solutions would require a system-based approach. In particular, water services (traditionally: wastewater, stormwater, and drinking water) should be integrated with the effort of maximizing the recovery of resources (i.e.: energy, nutrients, materials, and, obviously, water). The United States Environmental Protection Agency (US EPA) Safe and Sustainable Water Resources (SSWR) research program represented an example of a holistic approach to water resources management.

The rational utilization of the characteristics of sediment resources to achieve the optimal allocation of sediment resources is a key problem that must be solved urgently for ecological governance. On the basis of determining the allocation mode of sediment resources, this study established the multi-objective optimal allocation model of sediment resources, which aimed at the maximum ecological, economic, and social benefits and used the ε-constraint method and KuhneTucker condition to obtain the noninferior solution. Moreover, the optimal equilibrium solution of the model was obtained by using the subjective trade-off method from the perspective of preference. The Weishan and Bojili irrigation areas in China were then chosen as a case study to verify the feasibility and validity of the model. Results corroborate that, compared with the present situation, the proportions of sediment transport into the field in Weishan and Bojili irrigation areas are significantly increased and that the proportions of the main and branch canal sediment detention in the two irrigation areas are reduced. Compared with the results of the non-inferior solution, ecological and social benefits have been improved, and economic benefit has been decreased. The coordinated optimization of ecological, economic, and social benefits has been realized, instead of blindly pursuing economic benefit.

Introduction

Rivers and lakes are important for the early utilization of water resources, while reservoirs reflect the complex needs of modern human beings. Given the natural erosion and human activities, sediment siltation problem in rivers, lakes and reservoirs has become increasingly prominent. For instance, the Yellow River is the second largest river in China. With the inharmonious relationship between water and sediment and rapid increase in the utilization of hydropower resources, significant changes have taken place in the spatial distribution of sediments in the Yellow River in different periods, resulting in serious sediment disasters and ecological deterioration problems (Hu et al., 2010a). Sediment disasters have seriously affected the production and life of people, as well as the functions of rivers, lakes, and reservoirs (Rashid et al., 2015). Through turning disaster into wealth, making full use of the resource characteristics of sediments has become a potential way to solve the above problems. Disasters caused by sediments have been known. However, the resource characteristics of sediments have been accepted by the public only in recent years. Along the Yellow River, sediment resources are used for flood control and dike reinforcement, soil improvement of waterlogged salineealkali land, building materials, and other approaches, which provide significant ecological, economic, and social benefits (Chen et al., 2017). The main sediment treatment is centralized desilting through the desilting basin for a considerable time. However, with the long-term utilization, dredging sediment accumulates on both sides of desilting basin and channels. This buildup reduces the capacity of water and sediment transport in channels, increases the burden of drainage channels and dredging cost, and causes the desertification of land.

1- Introduction

2- Conceptual theoretical framework

3- Study area

4- Material and methods

5- Results and discussion

6- Conclusions

References

Abstract

Currently, many parts of the world are facing challenges resulting from poor water quality and water scarcity. To achieve water sustainability under this scenario, the main causes of water problems must be addressed while simultaneously dealing with their consequences. The development of a systemic perspective of water management is vital for facing such challenges. Integrated water resources management (IWRM) is one approach that analyzes water management from a systemic perspective, and structured systems analysis is a generalized and complementary approach that can facilitate the analysis of water management systems. The objective of this study was to perform a structural analysis of the water management system of the Nenetzingo River watershed (Mexico), with the goal of providing strategic and tactical guidance for the integrated water resources management of the watershed. Thus, in this study, a structural analytical method (cross-impact matrix multiplication applied to classification [MICMAC]) and a strategic planning perspective were employed. Modifications to the MICMAC method were necessary to comply with the objectives of the present study, leading to the proposal of an enhanced MICMAC method, denominated e-MICMAC. Overall, 49 variables were identified as relevant to the water management system of Nenetzingo, of which eight strongly influence the other variables and 10 are dependent on the dynamics of the system. In addition, nine variables serve as links between the influential and the dependent variables, while 18 variables were unable to be clearly characterized. Finally, three variables were excluded from the systems analysis without impact. Of the total variables, 22 were found to be essential to the system’s dynamics and were considered key variables. These key variables were then used to provide strategic and tactical guidance for the IWRM of the study basin. In conclusion, the structural analysis approach enabled the structure of the studied system to be elucidated. The variables that constituted the system were determined in addition to their relationships of influence or dependence. Lastly, the complexity of the analysis was reduced through the determination of key variables. The present structural analysis represents an important tool for achieving the sustainability of water resources in the Nenetzingo watershed and can strengthen planning measures in both the short and the long term while facilitates the definition of scenarios for the implementation.

Current challenges for water management

In 2013, according to the Global Water Partnership (Global Water Partnership (GWP, 2014), 770 million people worldwide lacked access to improved drinking water sources, and 2500 million people lacked access to adequate sanitation. Furthermore, 75 per cent of wastewater was incorporated into natural run-off without adequate treatment. As a partial consequence, 35 million people each year are currently expected to experience premature death as a result of water-related diseases. During this century alone, economic losses due to flooding and drought have reached approximately 1.9 billion dollars. Lalika et al. 2015 considered that failed policies have prevented the proper governance of water and watershed conservation. For this reason, the authors argued that attention should be placed on the development of capacities for water management among interested stakeholders, on the promotion of hydrological services and on the improvement of living conditions for local communities located within watersheds. In addition, Franzén et al. 2015 recommend promoting greater participation of stakeholders with interest in water governance and management of hydrological watersheds. However, during the identification of stakeholders, those related to all aspects of water management should be considered and not solely the water authorities or the users with the greatest weight in decision making. Up until the end of the past century, water management throughout the world was predominately concerned with satisfying demand. The apparent sufficiency of water supplies did not oblige a more in-depth analysis of new water sources or their exploitation. Nonetheless, the insufficiency of water supplies has become more notable in recent times, leading to the search for new management regimes to govern this vital resource. This search has highlighted that an efficient management of water demand considers factors and actors that are involved, from those related with natural water storage to the end users. Efficient management practices, for example, may aim to reduce the vulnerability of the water supply in the face of abundance or scarcity or to recycle used water back into the water supply.

Abstract

Nanotechnology is a multidisciplinary field that has gained significant momentum in recent years. Nanoparticles are the key players that have promised many benefits through their nano-enabled applications in multiple sectors. This review summarizes the use of nanomaterials such as zero valent iron (nZVI) and carbon nanotubes (CNT) in environmental cleanup like ground water remediation for drinking and reuse. There are, however, concerns regarding the potential risks associated with the use of nanomaterials to the environment and human health. An understanding of the relationship between the properties of nanoparticles and their in vivo effects would provide an effective strategy to tackle the deleterious effects.

Introduction

In recent years, nanoscience and technology has introduced a new dimension to scientific disciplines and technology sectors due to its ability to exhibit superfunctional properties of materials at nano-dimensions. There is a remarkable rise in research and development in all developed countries and many developing countries pertaining to this field. Organizations such as Universities, public research institutes and industrial R&D laboratories 1focus strongly on this new technology to benefit from its scientific and technological advantages [1]. Nanotechnology is a multidisciplinary field that applies engineering and manufacturing principles at molecular level [2]. In broad terms, nanotechnology is the development and use of techniques to study physical phenomena and construct structures in the physical size range of 1–100 nanometers (nm) as well as the incorporation of these structures into applications [3]. The past couple of decades have been dedicated to the synthesis, characterization, and application of nanomaterials

Water is recognized as a commodity fundamental to health but scarce, and achieving adequate water delivery to the public can be an overwhelming task anywhere in the world, especially when characterized by increasing population, urbanization and industrialization, as in developing countries especially. Yoe 2002, described associated problems with urban water supplies in achieving sustainability as a wicked task, since no answer can exactly be termed right, hence a compromise situation or solution is usually opted for. This is because the problem of uncertainty and human rationality is encapsulated in all wicked problems (Khisty and Mohammadi 2001). The renaissance to non-conventional or alternative water supply options are recognized as ecofriendly and sustainable, and their integration globally such as, reclaimed water, grey water, black water, rain water harvesting (RWH), desalination, borehole water, water importation, into water supply schemes is intrinsic. Hence exploring these pathways usually borders on the ‘soft path’ approach which suggest a combination of supply options that is usually not technology driven and viable, especially in new urban areas where no central infrastructure pre-exist. These systems undoubtedly can limit demand for fresh water resources, diversify water source, boost reliability of access to resource, and minimize volume of waste water discharged into the environment. These supply options over time, have undergone and undertaken diverse research patterns (Ukpong and Agunwamba 2012; Mara 2004; Dolnicar 2009; Contard and Gouvello 2013; Chowdhury and Rahman 2008; Kanakoudis et al. 2011; Angelakis and Gikas 2014). However the numerous difficulty, rigor, variability of criteria, and uncertainty encountered/ interplay during the decision making process for the best or appropriate supply option endears our employ of multi-criteria decision making approach (MCDA), a decision support tool in overcoming these shortcomings. Fuzzy TOPSIS (technique for order preference by similarity to ideal solution), is a MCDA approach, employed in this study for the first time in alternative water supply option, with consideration of the socio-cultural input in its analysis, a fundamental aspect of sustainability, to evaluate the preferred water supply alternative in the eastern Niger delta of Nigeria, based on economic, technical, environmental and socio-cultural criteria. This region is endowed with water resources including over 2200 mm of annual rainfall, but yet faced with gross inadequacies in water supply, evidenced by the proliferation of water vendors, a clear indication that supply are below acceptable levels. This condition is prevalent in most other parts of the country (Sule et al. 2010). (Okoli et al. 2010) identified major alternative sources of water in the region to be boreholes, wells and ground water.