Introduction

Managing the water assets of many countries around the world is a challenge due to immense difficulties and vulnerabilities, rapid industrialization and urbanization processes, and the effects of environmental changes, including global warming and climate change, as well as population’s growth and geopolitical instabilities. The increase in water stress and shortages facing many countries worldwide is one of the main difficulties confronting practical progress globally (Yuan and Lo 2022). According to FAO’s Director-General—José Graziano da Silva—this challenge will increase as the global population swells and as environmental changes continue to rise (FAO 2017).

According to the World Health Organization (WHO 2019), one in three people globally (or one-third of the world’s population) does not have access to safe drinking water. Also, regarding inequalities in access to water, sanitation, and hygiene (WASH), more than half of the world does not have access to safe sanitation services. Some 2.2 billion people around the world do not have safely managed drinking water services, 4.2 billion people do not have safely managed sanitation services, and 3 billion people lack basic hand-washing facilities. “Children and their families in poor and rural communities are most at risk of being left behind. Governments must invest in their communities if we are going to bridge these economic and geographic divides and deliver this essential human right,” said Kelly Ann Naylor, Associate Director of WASH, UNICEF (WHO 2019). Every year, approximately 300,000 children, who are less than 5 years old, die due to diarrhea linked to inadequate WASH. Poor sanitation and contaminated water are also linked to transmission of diseases, such as cholera, dysentery, hepatitis A, typhoid, and so forth. “Closing inequality gaps in the accessibility, quality, and availability of water, sanitation and hygiene should be at the heart of government funding and planning strategies. To relent on investment plans for universal coverage is to undermine decades’ worth of progress at the expense of coming generations,” said K.A. Naylor (WHO 2019).

Competition for water will escalate more than ever, as the world’s total population is projected to reach 8.6 billion by 2030 and 9.8 billion by 2050 (Islam and Karim 2019). It means that an additional 2.4 billion people are projected to be added to the global population between 2015 and 2050, whereas Africa will be the major contributor. On the other hand, the global water demand is projected to increase by 55% between 2000 and 2050 (Day 2019; Islam and Karim 2019). Effectively, many farmers in developing countries are suffering and will continue to suffer the ill-effects of the lack of access to freshwater, while clashes revolve regarding water resources arise around the world, especially in the presence of various scenarios related to the impacts of climate change (Salem 2009, 2011; Islam and Karim 2019; Avgoustaki and Xydis 2020; Do et al. 2020; Zhang et al. 2020; Salem et al. 2021; ZamanZad-Ghavidel et al. 2021). An example of the old–new conflicts over water resources is that amongst Ethiopia, Sudan, and Egypt, which share the Nile River waters in the African continent. Conflict amongst the three countries has been escalating recently, especially after Ethiopia had completed construction of the Grand Ethiopian Renaissance Dam (GERD) and finished the second filling of the Dam in July 2021, and recently started producing electricity (Yihdego et al. 2017a; Aljazeera 2020; Mbaku 2020; Colton 2021; El-Gundy 2021; Tadesse 2022; Tesfamichael 2022).

While there are clear indications of approaching water emergencies around the world, as confirmed by more ongoing events, including dry seasons and droughts, long-term pollution of water resources, and climate change impacts, policy- and strategy-makers have yet to deal with the resulting consequences (Zhang et al. 2020; ZamanZad-Ghavidel et al. 2021). The full range of difficulties, resulting from water scarcity in the short and long terms, will have heavy impacts on many countries worldwide, politically, socially, financially, and economically (Yihdego et al. 2019)—and these may lead in some regions, to military confrontations.

When focusing on changes and advances in strategies and management of water resources in the presence of extraordinary challenges, there is the need to overcome the latter. Regli and Heissermanb (2013) summarized such challenges into three basic elements—namely water (W), energy (E), and food (F), or WEF; and, in general, health and education, which can be explained in more detail as follows: (1) WEF will be major requirements for the human race’s ability to supply the global population, where the three WEF elements or subsystems are deeply interlinked and, thus, defined as “Nexus.” An example: energy and fertilizers are used to produce food and feedstock; water and feedstock are used to deliver meat (for example, it takes about 10 kg of feed and 15 L of water to deliver 1 kg of meat); and different food and non-food crops are used to provide biofuels (Ruel et al. 2018); (2) public welfare will continue to be a test and will be further affected by the provision of clean water and proper nutrition, the spread of diseases, and the transfer of medical services, such as the breakout of the Coronavirus (COVID-19) pandemic since December 2019 and ongoing (Worldometer 2022a); and (3) Education will be of increased importance, as it can lead to socioeconomic changes that can impact population’s development (Regli and Heissermanb 2013; Grant 2017; Yihdego and Salem 2017; Salem 2020).

The relationship between water, energy, and food (WEF Nexus) is fundamental to sustainable development. The WEF Nexus is a concurrent global assessment solution for developing and implementing different approaches focusing on the security and adequacy of the three resources or subsystems (water, energy, and food). The WEF Nexus’ approach aims to promote sustainable development and improve the quality of life of communities, while preserving natural, human, and social capital, addressing long-term sustainability challenges, and protecting natural resources and the environment. WEF Nexus is a holistic vision of sustainability that strives to balance the various goals, interests, and needs of people, as well as the well-being of the environment, by assessing water, energy, and food inter-relationships, inter-linkages, and inter-dependences through qualitative and quantitative modeling, as well as developing research and resource management to deliver important strategies for sustainable development in today’s dynamic and complex world.

This paper investigates the relationship between water and food (WF Nexus) in several regions across the globe, as they are presently facing water problems related to stress, shortages, pollution, distribution, and climate change, as well as inequity in water distribution, representing a violation of the “water right” as being a basic human right. Several water issues, including the WF Nexus, are investigated in this paper, focusing on five regions of the world, including the Gulf Cooperation Council (GCC) countries, Central Asia countries and the Caucasus, China, Africa, and Canada. These regions and the WF Nexus, in particular, are investigated in this paper for the following reasons:

(1) The authors are knowledgeable and have work experience about the five investigated regions, regarding various issues, such as population’s growth, socio-economic and environmental vulnerabilities, water resources’ mismanagement, inequalities, and so forth; (2) Some of the investigated regions are extensively considered as water-stressed areas, such as the Arab countries in the Gulf region (GCC countries); others have plenty of water, such as Canada, but suffer from water distribution inequity regarding the Canadian Native (Indigenous) population, and also from water pollution to some extent; while some other regions, like China and Africa, have enough water but suffer from the high population—a fact that considerably affects water resources. In addition, the countries of the GCC and Africa suffer from poor management or better saying mismanagement of their water resources. These criteria are negatively reflected, quantitatively and qualitatively, on the food security in the WF Nexus in these regions. Indeed, there are some other geographical regions around the world—such as northeastern Brazil, India, and others—that are suffering from acute water stress, shortages, drought, and other problems which, hopefully, will be investigated by another research paper and compared with the regions investigated by this one; 3) Several studies cited in this paper also focused on the water–food Nexus (Table 1) without giving attention to the energy element. Meanwhile, some other studies focused on the water–energy Nexus (WE Nexus) without giving attention to the food element, the energy–food Nexus (EF Nexus) without giving attention to the water element, and other studies focused on the three elements together, in terms of the WEF Nexus (Table 1); (4) The paper also investigates other issues referring to the water and food sectors, particularly when not directly related to the energy sector; and (5) Many regions around the world have no access to energy sources to generate electricity, meaning that they can live without energy—but they absolutely cannot live without water and food, despite the importance and necessity of energy for living.

Table 1 Various studies of the Nexus’ concepts (WEF, WE, WF, and EF), regarding countries and regions worldwide for the 2008–2022 period
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Methodology

To compare the different water-food challenges experienced in different regions of the world—which have different climatic and socio-economic conditions, this paper investigates water and food challenges in five different regions. It is based on a literature review and on data analysis, combined with the authors’ ample experience of the water situation in these regions. For this approach, quantitative and qualitative data were utilized and analyzed for the five regions investigated. Furthermore, several valuable, up-to-date articles were studied, analyzed, and provided in Table 1 to present a better and deeper understanding of the conditions and challenges facing the WF Nexus, as well as the WE Nexus, the EF Nexus, and the WEF Nexus in various regions of the world.

Results and discussion

WEF Nexus, WE Nexus, WF Nexus, and EF Nexus, globally

The water–energy–food Nexus (WEF Nexus), the water–energy Nexus (WE Nexus), the water–food Nexus (WF Nexus), and the energy–food Nexus (EF Nexus) guarantee access to safe and enough water, national food security and availability (in terms of quality and quantity), and national energy security, in an economically and environmentally sustainable manner. Recently (i.e., for the period 2008–2022), many researchers have studied the Nexus (WEF, WF, WE, EF), as well as other related issues mentioned above, regarding different countries and regions around the world (Table 1).

Based on the studies provided in Table 1, the Nexus’ approach (in terms of WEF, WE, WF, and EF) can promote sustainable development and improve the quality of life of communities, while preserving natural, human, and social capital, addressing sustainability challenges, and protecting the environment and natural resources for long-term use. Table 1 shows that the Nexus’ approach can help create effective commercial programs and synergies amongst the three subsystems (water, energy, and food) or two of them, taking into account cross-sectoral, environmental, social, political, and geopolitical dimensions, as well as social justice and equity. Thus, the Nexus’ concept is greatly relevant, especially in the presence of the impacts of climate change, population’s growth, and many other influencing factors (Table 1).

The Nexus amongst water, energy, and food (WEF Nexus) and how their complex interactions can be defined are essential approaches to understanding such a complex relationship amongst the three elements or subsystems. Such a Nexus can be defined as the very close links amongst the three elements (WEF) and how changes in one of them can have impacts on the other two (individually or both together) (Fig. 1). For countries worldwide, the WEF Nexus affects national water, energy, and food security and, thus, enabling socioeconomic developments.

Fig. 1
figure 1

Summary of the water–energy–food (WEF) Nexus (after Hoff (2011) and Albrecht et al. (2018) (left), and after Mahlknecht et al. (2020) (right))

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Water–food (WF) Nexus in five different regions of the world

The WF Nexus’ thinking is approached in this paper from the perspective of equitable and sustainable growth and the multi- and inter-disciplinary relationship amongst population’s growth, environment, climate change, society, economy (including green economy), finance, governance, innovation, urbanization, infrastructure, green cities, policy, synergies, trade-offs, governability, and, to some extent, water as a basic human right, international law, and regional geopolitics (Fig. 1).

To understand the interlinkages between the water and food subsystems (or elements), the following five regions were investigated in the present work, considering the variations amongst the different regions, concerning, for instance, climate, population, culture, socioeconomic conditions, and so forth.

a. Gulf Cooperation Council’s (GCC) Countries: The six Gulf Cooperation Council’s (GCC) countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates—UAE) constitute together an area of approximately 2.6 million km2 (more than a million square miles). The population estimates indicate that more than 60 million people live in all GCC countries, and their total GDP is USD 3.464 trillion (WPR 2022a, b).

More money will come to the coffers of the Gulf Cooperation Council countries as a result of the recent war between Russia and Ukraine. This is due to oil and gas prices that have skyrocketed to over USD 100. If this war would continue for an extended period of time, it will have dire implications and consequences for the global economy, stability, and security (see, for instance, Jones 2022; Power 2022; Whalen and Bogage 2022).

The GCC countries are considered some of the driest and most freshwater-stressed countries globally. Accordingly, reasonable water management has become a challenge to the GCC countries, separately and collectively, as being considered one of the most difficult assignments confronting them. Water in the GCC countries is made available through three resources: (1) Groundwater, which is usually replenished by seasonal rains that are decreasing year after year due to climate change impacts and large, ungoverned water consumption; (2) Desalinated seawater, which is supplied via modern, high-tech desalination plants; and (3) Wastewater treatment and reuse, which has been introduced relatively recently, and is obtained via wastewater and sewage treatment plants that supply water for agricultural purposes at limited scales only (Saif et al. 2014; Aleisa and Al-Zubari 2017; Yihdego and Salem 2017; Qureshi 2020; Salem 2021).

By expanding the areas used for agriculture and, thus, the water consumption to satisfy irrigation and population’s growth needs, the groundwater resources will dry out in the Gulf countries (Novo 2019; Al-Saidi and Hussein 2021). Estimates of the groundwater resources below the Saudi deserts have a range between 252 and 870 billion cubic meters (BCM) of “fossil groundwater” (NASA EO 2012a). On average, the Saudi deserts sit atop 500 BCM of fossil groundwater.

By 2008, 21 BCM of fossil groundwater were extracted annually to support modern intensive agriculture in Saudi Arabia (FAO 2008), whereas 87% of the water resources in Saudi Arabia go to the agriculture sector (Napoli et al. 2016; Ghanim 2019). By 2012, the consumption for human, industrial, and agricultural usages was 23.7 BCM/year (NASA EO 2012a). This fossil groundwater is used much faster than it can regenerate or replenish itself. The enormous imbalance between the current (as for 2020) groundwater discharge or consumption (currently 27.8 BCM/year) and fossil groundwater recharge (currently 5.3 BCM/year) causes the excessive lowering of groundwater levels in the aquifer systems in Saudi Arabia (Qureshi 2020). Accordingly, the discharge is approximately 5.25 (i.e., 27.8/5.3) times the replenishment rate of renewable groundwater resources. Other GCC countries have already reached a drawdown ratio of around 3:1, except for the UAE, where this ratio is much higher. Experts, accordingly, have estimated that 80% of the Saudi fossil groundwater has been gone (National Geographic 2012; DeNicola et al. 2015; Chandrasekharam 2018; Sultan et al. 2019; Bafarasat and Oliveira 2021). Over the past three decades (1990–2020), Saudi Arabia has been exploring and exploiting groundwater (fossil and replenished) at extremely severe rates, which is considered a resource that is more precious than hydrocarbons (oil and natural gas), especially Saudi Arabia and the other GCC countries have enormous sources of renewable energy, particularly solar energy (Basha et al. 2021).

Engineers and farmers have tapped into hidden water reserves to grow grains, fruits, and vegetables in the extremely hot deserts of Saudi Arabia. Figure 2 shows satellite images illustrating the evolution of agricultural operations in the Wadi As-Sirhan Basin, Saudi Arabia (NASA EO 2012b), as viewed by satellites over a period of a quarter a century (i.e., in 1987, 1991, 2000, and 2012).

Fig. 2
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Irrigation in Saudi Arabian deserts as seen from space (Image ID: DW64EE) for years—from left to right—1987, 1991, 2000, and 2012 (modified after Grist 2012)

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The average precipitation is only 100–200 mm/year, and it usually does not recharge the aquifer systems in Saudi Arabia and other GCC countries. On the other hand, about 17,300 km2 of irrigated areas will shrink in the foreseeable future due to water shortages; thus, resulting in a sharp reduction in the GDP contribution below 3%, which ascertains the groundwater as a non-renewable resource (Aboud et al. 2014; Chandrasekharam 2018; Pester and Zimmermann 2022). As for 2006, Saudi Arabia had 2.4 BCM of renewable freshwater resources on the surface, according to the Food and Agriculture Organization (FAO) (FAO 2008). Fossil groundwater in Saudi Arabia gave the nation hope of achieving its long-awaited goal of feeding itself rather than importing food from other countries. Saudi Arabia increased wheat imports from 1.92 million tons (MT) in 2013 to 3.03 MT in mid-2014, which was a short-term solution to circumvent water scarcity (Chandrasekharam 2018). In 2019/2020, Saudi Arabia imported 3.7 MT of wheat; 93.1% of the latter was imported from the European Union (EU) (Mousa 2021). However, as the war between Russia and Ukraine is currently going on, many countries worldwide, including Arab countries, will be badly affected regarding the wheat, corn, and cooking oils imported from Russia and Ukraine. This is due to the fact that Russia and Ukraine are primary exporters of these food products, worldwide (see, for instance, Arab News 2022; Quinn and Durisin 2022; TAW 2022).

Water management’s efficiency or good governance of water resources in the GCC countries, on the supply–demand side, is very low. On the supply side, the fraction of the physical spillage of non-revenue generating water in urban systems ranges from 30% to over 40% (Al-Saidi and Saliba 2019). This contrasts with the expense of desalinated water, which is somewhere in the range of USD 0.5–1.0 per cubic meter (Ghaffour et al. 2013; Al-Saidi and Saliba 2019). Currently, 439 desalination plants produce 5.75 BCM/year of desalinated water in the GCC countries (Qureshi 2020). The WF Nexus indicates how important seawater desalination is in the GCC countries and how it plays a major role in increasing drinking water supply and meeting water demands in the food and agricultural sectors—considering that the GCC countries collectively bear about 60% of the global production of desalinated water (Al-Farra 2015; Qureshi 2020).

b. Central Asia Countries and the Caucasus: The Central Asia and Caucasus region comprises five Central Asia countries—Uzbekistan, Kazakhstan, the Kyrgyz Republic, Tajikistan, and Turkmenistan—lying east of the Caspian Sea, and their three neighbors to the west of the Caspian sea, namely Azerbaijan, Armenia, and Georgia. The region is located near the center of the Eurasian continent, and its close proximity to Russia, China, the Middle East, Afghanistan, and Pakistan makes it vulnerable to geopolitical unstable regional conditions (Fig. 3). All countries in the region gained their independence after the collapse of the former Soviet Union in 1991. While they all seek to follow market economy systems, there are significant disparities in economic development due to each country’s natural resources and other factors such as pace of reforms (JICA 2010).

Fig. 3
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Map of the Central Asia Countries and the Caucasus (modified after Maps Owje 2022)

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In recent years, many Central Asian countries are striving to use water to generate hydropower from the Rogun Dam on the Vakhsh River, which is a branch of the Amu Darya River Basin (ADRB), representing Afghanistan’s northern border with Tajikistan, Uzbekistan, and Turkmenistan (Fig. 3). The Dam will provide hydropower to the upstream country—Tajikistan, while the downstream countries fear the opposite effect when flooding of the River will affect their horticulture in a very negative way. Despite some recent evaluations of the water assets’ management in ADRB, nothing to date tends to adversely negate the framework of the WF Nexus in the region of the Rogun Dam. To this connection, two basic methods of servicing the Dam were examined: (1) The energy situation, which ensures the hydropower needs of Tajikistan (WE Nexus); and (2) The deluge method, which guarantees water for agriculture for the downstream countries of the River (WF Nexus).

The outcomes that address the Rogun Dam (as aforementioned) show that the lifestyle can ensure a doubled vitality to Tajikistan, yet it will reduce access to water during the developing period, resulting in a 37% natural reduction in rural advantages in the downstream countries (Jalilov et al. 2016). In Central Asia, specifically, natural sciences and engineering professionals do not hold a prominent function in water assets’ management. Moreover, Georgia, Tajikistan, Turkmenistan, and Uzbekistan (Fig. 3) are the central notable countries that did not agree to the Espoo Conference. Armenia only confirmed the Protocol on Strategic Environmental Assessment (SEA Protocol), while Georgia and Moldova have marked the SEA Protocol but have not yet approved it (UNECE 2013).

In Moldova and Turkmenistan, national techniques for modifying environmental changes include water issues. An adjustment procedure for water supply and sanitation has also been drawn up in Moldova with the help of the Organization for Economic Cooperation and Development (OECD) and the European Union (EU). Kyrgyzstan has already built up a national methodology to adjust water assets’ management to face the impacts of environmental changes (UN OECD 2014).

c. China: In China, the total annual preserved water assets are around 2800–2841 BCM (Xie et al. 2009; MWR 2011). Even though the full water preserved has increased, making it the sixth-largest proportion of other nations on the Earth, the per-capita water assets were 2040 m3/ca/year in 2008, forming about a quarter of the global average (Liu et al. 2012). It is, in any case, an extraordinary share of water (2040 m3/ca/year) compared with other nations in different regions of the world. For example, in the Occupied Palestinian Territories—OPT), the per-capita water supply per year reaches, in some localities of the OPT, as low as 7.3 m3/ca/year (about 20 l/ca/day) (Salem and Isaac 2007; Isaac and Salem 2007; B’Tselem 2014; Hass 2014; Corradin 2016; Salem et al. 2021). However, this is not a result of water shortage but rather the geopolitics dominating the region. Israel (the occupation authority) is in almost total control of the Palestinian water assets (Corradin 2016; Salem et al. 2021).

Other than the generally few per-capita water assets in China, space allocation of water exacerbates the water shortage problem (Fig. 4). Ruled by the mainland rainstorm climate, 60–70% of annual rainfall in many regions of China is collected in summer times, whereas this rate is much higher in the northern parts of China (Cheng et al. 2009; Fang et al. 2021; Kondash et al. 2021; Yuan et al. 2021). Annual precipitation in China decreases little by little from the largest scale, over 2000 mm/year, to the lowest scale below 100 mm/year (Zhai et al. 2005; Ding et al. 2021). Also, the decrease in the annual precipitation in China has resulted in a clear increase of soil loss with precipitation up to mean annual precipitation of approximately 700 mm/year (Zhao et al. 2022). Water accessibility demonstrates a greater variation of space, whereas access to water assets is lower in northern China than in other regions of the country.

Fig. 4
figure 4

Spatial dissemination of the Chinese water and arable land assets: A spatial example of water usage assets. All information depends on heave normal run-away evaluation and populace for the time of the year 2000 (CIESIN 2010) with a spatial goal of 30 circular segments; B the number of people below the various amount of water pressure; C portion of developed terra territory. Developed land information is from Fischer et al. (2008) with spatial goals of 5 circular segment minutes; and D portion of viable land with water shortages (modified after Liu et al. 2013)

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The Huaihe, Haihe, and Huanghe (3H) waterways’ basins (ponds), mainly located in the North China Plain, account for 33% of China’s water, 35% of the water yield, 40% of the developed land in China, and 50% of the general grain production. However, this area forms only 7.6% of the country’s water assets (Guoyuan and Jiongxin 1987; FAO 2011; Liu et al. 2013; Yu and Wu 2018). The 3H-ponds are amongst the Chinese regions with severe water shortages. In contrast, the management of water assets is of critical importance to maintain water and sustenance provision, societal resilience, financial development, and natural well-being at the provincial and federal levels to a large extent. This is because of the uneven distribution of water assets and population, and due to the fact that 44% of China’s population lives in areas with severe water shortage (< 500 m3/ca/year) and 16% of the population lives in areas suffering from water shortages (500–1700 m3/ca/year) (Fig. 4A) (Liu et al. 2013).

Significant irregularities between water assets and arable land increase the water shortage problem. Arable land in China was only 0.08 ha/ca in 2008 and is still almost the same until recently (World Bank 2021), less than 40% of the average global level (FAO/WHO 2001; FAO 2021). The largest fertile land offerings are located in the North China Plain, the Northeast Plain, and the Sichuan Basin (Fig. 4C), yet these areas often suffer from real water shortages (Fig. 4A). Most of the developed arable land is located in deserted areas (Fig. 4D), including, for example, the North China Plain, which is known as “China’s Bread Box” or Bin. Rainfall is insufficient to help generate expanded yields; however, the well-managed water system is expected to achieve a highly efficient yield, or in other words, to accomplish high harvest efficiency (Liu et al. 2013), representing a good achievement towards the WF Nexus in China.

d. Africa: Africa is a unique mainland, but it harbors several traits and problems regarding societal structures, monetary systems, and common assets, among others. Africa’s multi-faceted ecology and natural resources require effective official responses to some formative measures (such as quality practices and their impacts on regional development), national assets, and security issues (Yihdego and Kwadwo 2017). Because of the mismanagement and high levels of corruption in many African countries, their governments are losing the financial revenues of their natural resources, including, for instance, the large revenues of energy (fossil and renewable) sources, considerably (Yihdego et al. 2017b, 2018a, b). Africa enjoys several renewable energy sources, including solar power, wind power, and hydro-power, which all have considerable values of the capacity factor (CF). The CF of a power plant is defined as the ratio of the actual energy produced in a given period to the hypothetical maximum possible (Yihdego et al. 2017b).

This also applies to issues related to water which, apart from its more considerable natural resources (surface and underground), are the heterogeneity of African landscapes and surroundings. Despite the efforts made by some African countries and the global network to advance, including, for instance, the achievements of the UN’s Millennium Development Goals (MDGs) and Sustainable Development Goals (SDGs), many countries in Africa have missed the targets, particularly concerning integrating water supply and sanitation (Daniel et al. 2014; EABW News 2019). This is despite the fact that Africa, in general, enjoys considerable amounts of annual precipitation, recharging the surface water and groundwater bodies in the continent (Fig. 5).

Fig. 5
figure 5

Map of the mean annual precipitation in Africa (modified after Al-Gamal and Hamed 2014)

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Settlements in Africa, either urban or semi-urban, have contradicting access to water assets and use and management. These contradictions must be evaluated and taken into account when determining specific strategies for water advancement and management (Yihdego et al. 2017a). For example, the Africa Water Vision 2025 (AWV 2025) promotes that Africa, where an unbiased and maintainable use and management of water assets exist, should alleviate poverty, improve financial revenues, encourage regional participation, and preserve nature (UN Water/Africa 2004).

Rapid population’s growth, improper water management, insufficient institutional plans, high rates of water consumption, pollution of water assets, climate change impacts, environmental degradation, deforestation, and low and unsustainable financing of interests in water supply and sanitation are all part of the significant risks that pose difficulties to manage water assets on the mainland Africa (Anelich 2014; Daniel et al. 2014).

Population’s growth is one of the major problems Africa has been facing. By 2020, Africa had over 1.36 billion inhabitants with a population’s growth rate of 2.49%, and the continent’s population will continue to increase significantly in the coming years, reaching nearly 2.5 billion people by 2050 (Saleh 2022). It is generally envisioned that risks cannot be dealt with effectively by adhering to the same age-old things in water assets’ management at the local, national, and regional levels. Attention to risk calls for appropriating good governance, community agreement and involvement, creative progress, and all the structures created for beneficial activities, guided by the AWV 2025, the UN’s MDGs, and the UN’s SDGs, urge African governments to deal with all water improvement issues, plus vitality improvement issues (Yihdego and Salem 2017).

One of the most severe difficulties that must be addressed if the AWV 2025 and the UN’s MDGs and the UN’s SDGs are to be achieved is the lack of trained personnel (specialized and administrative) and monetary and material assets. It is specifically important with what has been identified concerning the management and implementation of water and sanitation administrative issues and projects (Pietersen et al. 2006; Yihdego and Kwadwo 2017). Other than the labor shortage in the water assets’ management, there is a need for more qualified personnel in parts of water laws and regulations and financial matters for quantitative water assets. The low rate of retention of qualified staff, the lack of adequate preparation and underfunding, and generally the lack of research institutions affect, primarily, the water assets in Africa, though they are plenty. Likewise, there is a need to set a societal limit about WASH (USAID’s Water, Sanitation, and Hygiene projects) and the assets to be effectively used through instructions, institutional good management, and data correctness and availability.

There is primarily a lack of technical know-how and institutional quality, especially in Integrated Water Resources Management (IWRM), where delivery of good management of water assets is limited (Pietersen et al. 2006). Strengthening indicative boundaries, preparing limits at all levels, advancing harmonization, and enhancing information collection and sharing are all advantageous elements for IWRM in Africa (Daniel et al. 2014). The good news is that the United Nations has recently indicated that there is some progress taking place regarding IWRM in Africa (UNEP 2021).

e. Canada: It is easy for Canadians to assume that they have an almost endless supply of clean freshwater, as Canada harbors 7% of the world’s renewable freshwater (GoC 2018) (Fig. 6), with a total population of approximately 38.4 million as of July 2022—equivalent to only 0.48% of the total world population (Worldometer 2022b). In addition, Canada is the second-largest country in the area after Russia. Russia occupies 17.1 million km2 and Canada, 9.985 million km2—followed by the USA (9.857 million km2) and China (9.597 million km2) (CoW 2022).

Fig. 6
figure 6

Canada’s waterways map (modified after Maps Canada 2022)

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Approximately 60% of Canada’s freshwater drains to the north, while 85% of the total population lives close to Canada’s southern borders with the USA. This makes harnessing and managing the Canadian water resources a considerable challenge, both nationally and within individual provinces and territories. In 2013, 37 BCM of freshwater was withdrawn from Canada’s lakes, rivers, and underground aquifers (Pope 2019). Most of this water was used for industrial purposes, especially power generation, manufacturing, and agriculture (OMECC 2010; Loomer and Cooke 2011; McPhie and Post 2014; Roth and de Loë 2017).

Canada displays the following water characteristics (Fig. 6): Approximately 9% (891,163 km2) of Canada’s total area is covered by fresh surface water (rivers, lakes, and wetlands); Canada’s rivers drain 105,000 m3/s; The Mackenzie River is the longest river in Canada, with a total length of 4241 km; Canada has 563 lakes, covering an area of more than 100 km2; Wetlands in Canada cover an area of more than 1.2 million km2 (14% of the size of Canada’s land), forming approximately 25% of the world’s wetlands, and making Canada the largest wetland’s area in the world; Glacial ice, over 100,000 years old, has been found at the base of several ice caps in the Canadian Arctic; Glacial erosion created a number of lakes on the Canadian Shield, including the Great Lakes; It is estimated that about 2% (200,000 km2) of Canada’s area is covered by glaciers and icefields; There are currently 2921 active water level and stream flow stations, operating in Canada; and Canada’s longest inland waterway runs 3700 km from the Gulf of St. Lawrence to Lake Superior (AWPS 2012; Freeman 2016; Pomeroy et al. 2019).

To face the escalating water problems in Canada, including those naturally caused or manufactured (man-made), the following strategies are recommended to be taken by the Canadian Federal Government: (1) Creating a “Canada Water Security Centre” that measures, investigates, monitors, predicts, stores, and disseminates comprehensive data and information about all water resources in the country. Such data would enable the center to respond to all water problems that are resulted naturally and anthropogenic, including floods, droughts, pollution, shortages, etc.; (2) Establishing a “National Water Committee” that promotes transboundary water management, prioritizes the protection of intact basins of the lakes and rivers, and directs water management and climate change mitigation and adaptation measures and strategies; (3) Improving cooperative planning of lakes and rivers’ basins, by building enduring partnerships for water management and decision-making with provinces, territories, and Indigenous governments. It is to be with a clear outcome for building resilience in the face of extreme events, identifying priority areas for restoration of lakes and rivers’ basins, and ensuring that ecosystem requirements are met across levels of jurisdiction and authority; and (4) Promoting reconciliation with the First Nations’ Indigenous (FNI) communities, by ensuring that the Canadian Water Law is consistent with the United Nations Declaration on the Rights of Indigenous Peoples (UN DESA IP 2007; HRW 2016), and adopting a consent-based, co-drafting approach to law renewal in partnership with local Indigenous governments (Schraeder 2009; OMAFRA 2016; Roth and de Loë 2017; Pomeroy et al. 2019; TCC 2021).

The access to sufficient, affordable, and safe drinking water and adequate sanitation is easy for most Canadians. However, this is not the case for many First Nations Indigenous communities. In stark contrast, the water supplied to many FNI’s communities on the lands, known as “Reserves,” is polluted, difficult to access, and endangered due to defective treatment systems. The Canadian Federal Government regulates water quality for Canadian communities, but has no binding water regulations on the Canadian FNI’s Reserves. A recent investigation carried out by the Canadian Broadcasting Corporation (CBC) revealed that 180 homes in Garden Hill First Nation, Manitoba, Canada, lack running water and indoor plumbing, and some residents do not have central heating or electricity (CBC 2019; Palmater 2019). “We found that the Canadian government has violated its international human rights obligations toward First Nations persons and communities by failing to remedy the severe water crisis” (HRW 2016, 2019). According to Palmater (2019), “The First Nations water problems [are] a crisis of Canada’s own making. How many Canadians would settle for water infected with fecal matter, sewers backing up into their bathtubs or being able to bathe only once a week due to lack of access to water? In all likelihood, if this were happening in any Canadian municipality on the same scale as in First Nations, a state of emergency would be declared and all resources would be brought to bear to address the crisis.”

The quality of drinking water’s supplies in rural and FNI’s communities has dramatically deteriorated in recent decades, resulting in more than 100 drinking water’s warnings for Reserves in Canada as of 2015, which have enforced some FNI’ Reserves to boil water, and pay for water delivery and transportation costs. Accordingly, since 2015, the Canadian Federal Government has spent CD (Canadian Dollar) 2 billion to improve access to safe, clean drinking water in FNI’s communities (Pomeroy et al. 2019). This laudable goal is to address the symptoms, but not the basic water problems that are facing the Indigenous population in Canada, according to Pomeroy et al. (2019). The inherent rights, laws, and jurisdiction of the Canadian Indigenous population in waters, as well as negotiated treaties, land claims, and governance agreements, all point to their role as full partners in decision-making, regarding water and other natural resources, as well as land use.

On another point regarding water in Canada, the big fear for groups like the “Council of Canadians” is that it will end up treating water as a commodity and that huge quantities of water will be funneled south to dry regions like California in the USA, through wholesales or water diversion projects. Successive Canadian governments, however, have pledged to never allow such sales and no deals have yet been struck. For instance, attempts to sell large quantities of water from Lake Superior and Newfoundland were only banned due to public pressures (Freeman 2016). Nevertheless, the Canadian Federal Government has firmly expressed that it will not allow exports of water to foreign countries (AWPS 2012).

Water conservation modeling and development strategies

In the twenty-first century, modern water management modeling provides an excellent opportunity for an astonishing scale to investigate and manage water utilization. Water management modeling mitigates the continuous financial wastes resulting from development in the water sector. Traditional water conservation projects aimed to boost financial attributes, such as GDP. Future water conservation modeling needs to be emphasized by amplifying the overall estimates of economic, social, agricultural, and environmental benefits.

A system should be built that includes both financial and ordinary capital (i.e., estimates of biological system’s administrations in nature) (Carpenter et al. 2011) to assess biological community administrations of the oceans, seas, rivers, lakes, wetlands, and other water bodies; competition uses of conserved water; and actions that support the whole conserved water security bargains.

Water conservation in China, for instance, has put great attention to the foundations and primary goals of restricting waterways. The benefits of putting resources into premium protection are largely overlooked. For example, only about 3.3% of concerns in conserving water safety will be devoted to ensuring soils and waters’ well-being and extending natural recovery in 2010. Hence, water conservation in the future needs to revitalize environmentally friendly projects (Tortajada 2001; Shucheng 2006; Jiao 2009; WBDG 2021), whereas many of the projects carried out nowadays use various strategies, including smart growth, compact development, green building, green economy, and green infrastructure that all aim at water and environmental sustainability (EPA 2021).

Likewise, it is important to move from mere “boom repulsion” to “give the increase method” (Yin and Li 2001; Opperman et al. 2009). To this end, giving water bodies (rivers, lakes, etc.) a chance to recover, introduced by former Chinese President Hu Jintao in mid-2008, can be an option. However, future water conservation projects need to look unambiguously at moving examples of environmental evolution. Water bodies in China were regulated and largely operated without thinking of environmental changes. Such a firm plan of projects is flawed at the elementary level (Milly et al. 2008; Matthews et al. 2011; Pittock and Hartmann 2011). Environmental changes in previous years have just caused noteworthy adjustments in water assets in China (Piao et al. 2010; Xie 2020; Xia et al. 2021).

One model is a strong evidence of the drying pattern in the Hanjiang River Basin (which is a tributary of the Yangzte River), China. If such a pattern continued, the Hanjiang River would have no additional waters to occupy unless it gets water from elsewhere first. Therefore, the Chinse Government built the South-to-North Water Transfer Project (SNWTP)—also known as the South-to-North Water Diversion Project (SNWDP) (Liu and Zheng 2002; Chen et al. 2007; News & Focus 2016; Zhang and Donnellon-May 2021) (Fig. 7).

Fig. 7
figure 7

South-to-North Water Transfer (Diversion) Project (SNWTP or SNWDP), China (modified after Zhang and Donnellon-May 2021)

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The SNWTP comprises three water transfer or diversion routes in the Eastern, Central, and Western China, diverting water from the lower, middle, and upper reaches of the Yangtze River, respectively (Fig. 7). It also connects four major rivers—the Yangtze River, Huai River, Yellow River, and Hai River. Thus, the SNWTP establishes a pattern of water resources’ allocation in China that regulates three south–north water routes and connects four west–east rivers. The SNWTP will supply a total of 6.15 BCM/year of water to the Jingjinji region in 2020 through the Middle Route (Phase I) and the East Route (Phase II), and also 8.58 BCM/year in 2030 through the Middle Route (Phases I and II) and the East Route (Phases II and III) (Fig. 7). The total water diversion’s capacities of the SNWTP have already reached, just recently, 7.4 MCM/year, and are expected to reach 12 BCM/year soon (Falkenmark and Rockström 2006; Liu et al. 2009; Kobayashi and Porter 2012; Li et al. 2019; Yuan et al. 2021).

In view of the above, the SNWTP is a mega project, representing a key strategic infrastructure, aiming at improving the allocation of water resources in China. It plays a vital role in alleviating the severe water shortage in northern China, ensuring water supply, promoting sustainable social and economic development, and improving the ecological environment. Given the importance of green water projects, such as the SNWTP in China, the future focal point for water conservation should be shifted from the viewpoint of the blue-water projects towards considering water security as “reasonable,” including green-water streams (Falkenmark and Rockström 2006).

Challenges of carrying water conservation goal

Water management and water use should be collaborative between the communities and respective governments. In northern China, for example, with the ultimate goal of relieving water shortage, the SNWTP (mentioned above) has been activated with a planned total exchanged volume of 12–43 BCM/year in the next few decades (Ma et al. 2006; Liu and Savenije 2008; Li et al. 2019). Along these lines, the scarce-water regions in northern China provide much sustenance to the water-rich areas of southern China each season. Thus, the effective water movement installed by a reciprocal vessel is identical to 52 BCM/year (Ma et al. 2006; Liu and Savenije 2008), which is greater than the real level of the exchange project (Shao et al. 2003).

In the same manner, leaders and policy-makers must be highly conscious and environmentally knowledgeable regarding the building of water-exchange projects. In water-scarce regions, the effectiveness of water-exchange projects is generally restricted by adjacent water uses and water-saving incentives between different water-customer divisions. For example, water disturbances of the Tarim River in China reduced the distance of the far-stream path from about 850 km in 2001 to about 400 km in 2002 and 2003, meaning a more than 47% reduction of the length of the far-stream way (Liu et al. 2013). It also shortened the water-scarce season from 185 days in 2001 to 46 days in 2003, meaning more than 75% shortening of the water-scarce season only within three years (Liu et al. 2013). However, in 2009 the distance expanded to about 1200 km, while the period that had become visibly scarce grew to 302 days. Being preoccupied with water scarcity would not be beneficial for reducing the distance and time over the entire range. One crucial reason is that neighborhood residents use more water than currently for residential, industrial, and agricultural purposes. With no change in monetary composition and first-ranked water use, the water preoccupation alone cannot address the water shortage problems (Salem 2011, 2019a; NAE 2017; Stephenson 2018; PSE 2017; Salem et al. 2021).

Advantages and disadvantages of sustainable water conservation and applications for food

One of the direct advantages of the water reorientation or redirection projects, such as the cases of many projects in China, including, for instance, the SNWTP (mentioned above), is the exchange of water from areas of surplus water to areas of water shortages, to alleviate water shortages in certain regions. This water preoccupation extends to larger sizes and is expected to provide water for domestic and other uses, especially those areas that have lower amounts of water or those that suffer from water shortages, such as the Tianjin city (Fig. 7, above), which has the most insufficient per-capita water assets in China (180 m3/ca/year). The Beijing-Tianjin-Hebei district—Jingjinji—is China’s most densely populated region. Problems arise from the acute shortages of water resources, with the emergence of water issues for landowners, such as establishing water diversion projects, regional synergies development, and the impacts of climate change (Li et al. 2019). Water shortages in some regions of China, such as the North China Plain, particularly due to climate change, have led to extreme droughts affecting wheat production (Yang et al. 2020). Therefore, water transfer or diversion projects in China are of particular importance.

The Yin Luan Ru Jin water project began in 1982 to relieve the water shortage in Tianjin. By 2009, this project had redirected 19.2 BCM of water to Tianjin, primarily residential and industrial. Another example is the Yin Huang Ru Jin project in China, which aimed to deliver water from the Yellow River to Shanxi province (Fig. 7, above), which possesses a quarter of the total coal preserved in the country. Each year, the project offers 0.56 BCM to the cities of Datong and Shuozhou and 0.64 BCM to the city of Taiyuan, as well as to three noteworthy coal mines in that region of China.

The Yin Jiang Ji Tai project aimed to improve the water transport from the Yangtze River to Taihu Lake. As the third-largest freshwater lake in China, Taihu Lake is a noteworthy water hotspot for drinking, aquaculture, and industrial needs and is a popular vacation destination. The region of the Taihu Lake represents 0.4% of the total area of China, 2.9% of the world’s population, and 14% of China’s real GDP (Yang and Liu 2010; Hu et al. 2022).

Sustainable water conservation achievements models

At present, China, for example, has more than 20 noteworthy projects amongst the waterways with a total length of more than 7200 km. The main feature of allocating space for those projects is mainly in northern China. As indicated in China Vision 2006, the projects to redirect water between various water bodies represent 2.5% of the Chinese total surface water assets. This proportion may increase to 10% upon completion of the SNWTP (mentioned above) in 2050 (Cheng et al. 2009). The SNWTP, with a total length of 3187 km, is the most extended water running project on the planet Earth. This project, the largest of its kind globally, has benefited over 100 million people in the country’s parched north by transferring water from the water-rich Yangtze River basins in the south (CISION 2019). The SNWTP, began in 2002, consists of three lines or routs (as mentioned above): Western, Central, and Eastern (Fig. 7, above). The water on the Central Route traverses more than 1400 km in its 15-day trip, starting from Danjiangkou Reservoir in the Hubei province, travels across the Henan and Hebei provinces before arriving in Beijing and Tianjin. The Eastern Route starts from Yangzhou in the Jiangsu province and ends in Shandong province and Tianjin. Estimates of the project’s cost differ enormously (Lin 2017). Approximately USD 43 billion (equivalent to around Chinese Yuan 288.15 billion, as of July 2022) were invested in this mega project by the Central Government of China, and over 400,000 people living in water-source areas along the three routes have been resettled (CISION 2019). The areas fed by the project produce 1/3 of China’s GDP. So far, with its three routes, the SNWTP project has transferred approximately 60 BCM since it was launched in 2013 (CISION 2019).

Challenges of securing water for food (water-food Nexus)

The water-for-nutrition challenge (in terms of WF Nexus) is a showcase for moving forward with a promise to reinvigorate science, innovation, development, and commercial enterprise (Table 1, above). By understanding the WF Nexus, distinct factors accelerate the advancement of science, innovation, synergies, trade-offs, and market-driven methodologies (Table 1, above). These factors are essential for reducing water shortages in the food-assessment chain and enhancing water management to support food security and alleviate and ease destitution, especially with the consideration of global warming and climate change impacts. These factors are:

(1) Improving water efficiency and wastewater reuse: These two goals can fundamentally expand the profitability of restricted water assets, especially in the food supply chain, where water assets can have multiplier impacts at different levels of the economy; (2) Effective water capture and storage systems: These two procedures are essential for expanding rapid access to water supply in areas where rainfall is regular. With projected increases in rainfall variability, due to environmental changes and climate change impacts, as well as due to expanded food generation demands, capacity frameworks at different levels are expected to anchor water supplies and build strength for droughts consistently; and (3) Salinity of the water supply: Increasing water salinity is a considerable risk to water resources, mainly due to climate change impacts and other causes. Thus, increased water salinity poses an induced risk to food production. For instance, in groundwater aquifers and coastal areas, over-pumping and rising sea levels cause a considerable increase in freshwater salt content (Salem 2011; Liu and Liu 2014; Llovel et al. 2019; Said et al. 2021). However, in many regions around the world, people are witnessing sea-water rise due to climate change. There are some reasons for long-term sea-level changes, including, among others, astronomical, meteorological, and steric, such as water salinity and temperature (Boateng 2010; IPCC 2019).

Future needs for securing water for food (water–food Nexus)

Water shortages across the globe represent one of the most difficult challenges facing development in the twenty-first century; nearly 3 billion people, over 38% of the world’s total population (7.96 billion as of July 2022) (Worldometer 2022c), live in watercourse regions affected by water shortages as well as water pollution and geopolitical instabilities. These 3 billion of the world’s population can be divided into almost two halves. The first half (≈ 1.5 billion) lives in areas significantly affected by severe water shortages, where demand is more prominent than supply. The other half (≈ 1.5 billion) faces cash shortages of water and restrictions in access to water, despite its availability and, in some cases, its abundance. The second kind of water shortage is attributed to institutional, budget, human, and geopolitical variables and conditions, at the expense of locations affected by wars or under military occupation, similar to the conditions in the Occupied Palestinian Territories (Salem 2011; Salem et al. 2021). Water shortages in the second case are defined by physical, financial, political, and geopolitical effects, such as water control and hegemony by powerful governments (Zeitoun and Allan 2008; Wessels 2015; al-Shalalfeh et al. 2017; Salem 2019b; Gebrehiwet 2020; Putra et al. 2020; Salem et al. 2021).

However, both kinds of water shortages can lead to specific negative consequences in terms of welfare, the profitability of agriculture, military confrontation, terrorism, environmental degradation, business deterioration, and lack of sectoral and socioeconomic development. Between 2000 and 2050, overall water demand is expected to increase by 55%, as indicated above. Three activities will contribute to the overall 55% increase in water demand: (1) Manufacturing, with a 400% increase; (2) Thermal electricity generation, with a 140% increase; and (3) Domestic use, with a 130% increase (UN OECD 2012; Day 2019). Accordingly, the rapidly growing water demand for several purposes, such as urbanization, industrialization, energization, and development, in general, will be a great challenge facing the water supply for irrigation by 2050. It is particularly important if we are aware that more than 70% of the water use worldwide occurs in the Food Value Chain (FVC) (Fig. 8). Therefore, the number of individuals affected by water shortages and water stress will continue to rise, especially amongst poor people in developing countries worldwide.

Fig. 8
figure 8

Food value chain (FVC) from farm to fork (modified after, and adapted from, SWF 2017)

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Securing water-for-food systems (water–food Nexus)

As already mentioned, countries across the globe are presently facing water shortage problems, some of which are severe and others are moderate. Such problems will be even more complicated in the presence of climate change impacts and population’s growth. Thus, the countries will constantly be confronting such problems, given the way to 2050. Accordingly, country researchers, approach builders, system builders, policy- and strategy-makers, and so forth must move away from discovering short- and long-term measures to efficiently manage the water shortage issues (SWF 2017). Therefore, understanding the conditions for enabling neighborhoods for innovation and commercial advancement is a crucial issue to explain the social, environmental, institutional, legal, and administrative difficulties facing development and how to overcome those barriers, considering nearby economic conditions. The proximity of the “establishing water for food” program (WF Nexus) in developing countries is essential. It is also essential to identify the neighborhood with which it cooperates to establish the projects needed.

Conclusion and recommendations

While there are clear indications that water and food emergencies are approaching worldwide, as confirmed by more current events and challenges, including dry seasons and resulting droughts, long-term pollution of water resources, and the impacts of climate change, as well as geopolitical instabilities and military conformations, it is noteworthy to mention that strategy- and policy-makers have not made enough efforts to deal with such events and challenges and the consequences resulting from. With the focus on changes and advances in water and food resources’ strategies and management, in the presence of these extraordinary challenges and frequently happening events, it is needed to surmount these events and challenges—one of the mechanisms to deal with them in implementing the Nexus’ approach or framework.

Demands on water (W), energy (E), and food (F) are growing worldwide, driven by a growing global population, rapid urbanization, changing diets, and economic growth. Agriculture is the world’s largest consumer of freshwater resources, and more than a quarter of the energy used globally is consumed during food production and supply. Accordingly, this paper can help managers effectively manage water resources and conceptualize a comprehensive WEF Nexus’ policy or just a WF Nexus’ policy, considering that the energy subsystem is not investigated in this work for the reasons mentioned above.

The present evaluation’s results could be used as tools to strengthen the WF Nexus management and governance. Each country has unique economic and social characteristics that directly or indirectly affect the WF Nexus. Therefore, it is almost sure that the stewardship of water assets will be a vital issue in building an efficient WF Nexus’ framework that will enable socioeconomic development and progress. It is suggested that socioeconomic indicators and their interactions with the WF Nexus (or WEF Nexus) are analyzed regarding the various regions investigated.

The outcomes of this work can guide managers and decision-makers to develop possible solutions, ensuring water-management tools are applied successfully according to the visions of multiple perspectives, which can help the relevant ministries and institutions improve plans and policy- and strategy-making related to WF Nexus. This means that before essentially ‘giving more water’ (i.e., the supply–demand management’s approach), which often refers to developing new and costly foundations and infrastructures, the first and wisest things to do are the enhancement of water effectiveness within the framework of water–food Nexus’ management, and also paying attention to issues at the exciting side. Such approach should be undertaken without seriously harming or altering the well-being of humans and the environment.