Editorial

8 pages, 227 KiB

Open AccessEditorial

Arjen Y. Hoekstra: A Water Management Researcher to Be Remembered

by Maarten S. Krol, Martijn J. Booij, Rick J. Hogeboom, Fatemeh Karandish, Joep F. Schyns and Ranran Wang

Water 2022, 14(1), 50; https://doi.org/10.3390/w14010050 - 27 Dec 2021

Viewed by 5404

Abstract

On 18 November 2019, the life of Arjen Y [...] Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

Research

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11 pages, 750 KiB

Open AccessArticle

Water Value Flows Upstream

by Hubert H. G. Savenije and Pieter van der Zaag

Water 2020, 12(9), 2642; https://doi.org/10.3390/w12092642 - 22 Sep 2020

Cited by 5 | Viewed by 2892

Abstract

Arjen Hoekstra postulated in 2001 that the value of water accumulates in an upstream direction: water value flows upstream. The ultimate source of this value is the rain. This original idea he used to develop the water value-flow concept. This article shows that [...] Read more.

Arjen Hoekstra postulated in 2001 that the value of water accumulates in an upstream direction: water value flows upstream. The ultimate source of this value is the rain. This original idea he used to develop the water value-flow concept. This article shows that the water value-flow concept has much to offer in terms of contemporary challenges. It is fully consistent with the "Five Bellagio Principles on Valuing Water" that the High Level Panel of Water published in 2017, and can make significant contributions to the first four principles. This article also shows that the concept can make many more contributions, including incorporating precipitationsheds, and thus include the source areas of rainfall in valuing water. Yet, until now, this innovative and potentially ground breaking concept has been largely ignored by researchers and practitioners in the fields of water resources management and economics. We conclude that the value-flow concept is a unique and promising framework for the integrated assessment of the value of water within a water resources system or river basin. We suggest that the concept can be enriched by incorporating instream benefits, water quality, as well as social, cultural, and spiritual values. We also suggest to test whether the concept can be usefully applied, and add value, to the emerging fields of socio-hydrology and water accounting. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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17 pages, 929 KiB

Open AccessArticle

Water Footprint and Virtual Water Trade: The Birth and Growth of a New Research Field in Spain

by Maite M. Aldaya, Alberto Garrido and Ramón Llamas

Water 2020, 12(9), 2641; https://doi.org/10.3390/w12092641 - 21 Sep 2020

Cited by 4 | Viewed by 4498

Abstract

The growth in the number of studies applying and expanding the concepts of the water footprint and virtual water trade in Spain has generated a wealth of lessons and reflections about the scarcity, allocation, productive use, and management of water from the viewpoint [...] Read more.

The growth in the number of studies applying and expanding the concepts of the water footprint and virtual water trade in Spain has generated a wealth of lessons and reflections about the scarcity, allocation, productive use, and management of water from the viewpoint of a semi-arid country. This paper reviews the evolution of this research field in Spain since its introduction in 2005 and reflects on its main contributions and issues of debate. It shows how these concepts can be useful tools for integrated water accounting and raising awareness, when used with certain precautions: (1) Supply-chain thinking, taking into account value chains and the implications of trade, generally ignored in water management, can help to address water scarcity issues and sustainable water use. (2) Green water accounting incorporates land use and soil management, which greatly influences hydrological functioning. (3) The grey water footprint indicator analyzes pollution from an ecosystem point of view and facilitates the understanding of the water quantity and quality relationship. (4) Apparent water productivity analysis, innovatively incorporated into Spanish studies, considers the economic and social aspects associated with water use. However, the decision-making context should be broader, contextualizing and complementing water information with other indicators. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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Review

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15 pages, 338 KiB

Open AccessFeature PaperEditor’s ChoiceReview

A Review of Water Stress and Water Footprint Accounting

by Dan Wang, Klaus Hubacek, Yuli Shan, Winnie Gerbens-Leenes and Junguo Liu

Water 2021, 13(2), 201; https://doi.org/10.3390/w13020201 - 15 Jan 2021

Cited by 55 | Viewed by 11955

Abstract

Production and consumption activities deplete freshwater, generate water pollution and may further lead to water stress. The accurate measurement of water stress is a precondition for sustainable water management. This paper reviews the literature on physical water stress induced by blue and green [...] Read more.

Production and consumption activities deplete freshwater, generate water pollution and may further lead to water stress. The accurate measurement of water stress is a precondition for sustainable water management. This paper reviews the literature on physical water stress induced by blue and green water use and by water pollution. Specifically, we clarify several key concepts (i.e., water stress, scarcity, availability, withdrawal, consumption and the water footprint) for water stress evaluation, and review physical water stress indicators in terms of quantity and quality. Furthermore, we identify research gaps in physical water stress assessment, related to environmental flow requirements, return flows, outsourcing of water pollution and standardization of terminology and approaches. These research gaps can serve as venues for further research dealing with the evaluation and reduction of water stress. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

21 pages, 6397 KiB

Open AccessReview

The Water Footprint of the United States

by Megan Konar and Landon Marston

Water 2020, 12(11), 3286; https://doi.org/10.3390/w12113286 - 23 Nov 2020

Cited by 21 | Viewed by 6447

Abstract

This paper commemorates the influence of Arjen Y. Hoekstra on water footprint research of the United States. It is part of the Special Issue “In Memory of Prof. Arjen Y. Hoekstra”. Arjen Y. Hoekstra both inspired and enabled a community of scholars to [...] Read more.

This paper commemorates the influence of Arjen Y. Hoekstra on water footprint research of the United States. It is part of the Special Issue “In Memory of Prof. Arjen Y. Hoekstra”. Arjen Y. Hoekstra both inspired and enabled a community of scholars to work on understanding the water footprint of the United States. He did this by comprehensively establishing the terminology and methodology that serves as the foundation for water footprint research. His work on the water footprint of humanity at the global scale highlighted the key role of a few nations in the global water footprint of production, consumption, and virtual water trade. This research inspired water scholars to focus on the United States by highlighting its key role amongst world nations. Importantly, he enabled the research of many others by making water footprint estimates freely available. We review the state of the literature on water footprints of the United States, including its water footprint of production, consumption, and virtual water flows. Additionally, we highlight metrics that have been developed to assess the vulnerability, resiliency, sustainability, and equity of sub-national water footprints and domestic virtual water flows. We highlight opportunities for future research. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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15 pages, 1976 KiB

Open AccessReview

Water Resources for Sustainable Healthy Diets: State of the Art and Outlook

by Davy Vanham

Water 2020, 12(11), 3224; https://doi.org/10.3390/w12113224 - 18 Nov 2020

Cited by 13 | Viewed by 3506

Abstract

Sustainable healthy diets are high on the research and policy agendas. One of the crucial resources to provide such diets are water resources. This paper provides a brief overview of the current research state regarding this topic, with a focus on the water [...] Read more.

Sustainable healthy diets are high on the research and policy agendas. One of the crucial resources to provide such diets are water resources. This paper provides a brief overview of the current research state regarding this topic, with a focus on the water footprint concept, as latter quantifies water use along a supply chain. The water footprint (WF) quantifies blue and green water consumption, as both these water resources are essential for food and energy production as well as for the environment. Different kinds of information are embedded in a dietary WF and different data sources and modelling approaches exist, leading to WF dietary amounts that are not always directly comparable. A full sustainability assessment of a dietary WF encompasses three components: (1) an equity assessment of the total WF amount; (2) an efficiency assessment for each food item in the diet as well as (3) an impact assessment (blue water stress and green water scarcity) for each food item in the diet. The paper concludes with an outlook on future research on the topic, listing the following points: (1) future clarity in system boundary and modelling assumptions, with comparison of results between different approaches; (2) full sustainability assessments including all three components; (3) dietary footprint family assessments with the WF as one member; (4) WF assessments for multiple dietary regimes with support to the development of local dietary guidelines and (5) assessment of the synergies with LCA-based mid-point (scarcity-weighted WF) and end-point (especially human health) indicators and evaluation of the validity and empirical significance of these two indicators Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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14 pages, 896 KiB

Open AccessFeature PaperReview

Water Footprint Study Review for Understanding and Resolving Water Issues in China

by La Zhuo, Bianbian Feng and Pute Wu

Water 2020, 12(11), 2988; https://doi.org/10.3390/w12112988 - 25 Oct 2020

Cited by 11 | Viewed by 6219

Abstract

The water footprint (WF) is a widely recognised and comprehensive indicator of both the direct and indirect appropriation of freshwater. It has been utilised for diverse functions, including as a key indicator of the planetary boundaries and United Nations Sustainable Development Goals. Focusing [...] Read more.

The water footprint (WF) is a widely recognised and comprehensive indicator of both the direct and indirect appropriation of freshwater. It has been utilised for diverse functions, including as a key indicator of the planetary boundaries and United Nations Sustainable Development Goals. Focusing on the nation with the greatest WF, i.e., China, this study reviews journal articles both in English and Chinese published from January 2003 to June 2020. Using CiteSpace and bibliometric analysis of papers, journals, and keywords, we explore state-of-the-art WF accounting, driving forces, and effects. Visible differences in WF accounting keywords and spatial scales between English and Chinese literature are identified. Reported WF values for the same product varied across studies, and there was a lack of information regarding uncertainties. Key driving factors have been largely investigated for agricultural WFs but not for other sectors. The WF impact analyses primarily assess the environmental effects, ignoring the associated social and economic impacts. The development of WF studies has improved our understanding of water issues in China. However, there are still existing knowledge gaps to be filled to find solutions to WF-related issues. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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16 pages, 1276 KiB

Open AccessReview

Burning Water, Overview of the Contribution of Arjen Hoekstra to the Water Energy Nexus

by Winnie Gerbens-Leenes, Santiago Vaca-Jiménez and Mesfin Mekonnen

Water 2020, 12(10), 2844; https://doi.org/10.3390/w12102844 - 13 Oct 2020

Cited by 4 | Viewed by 4554

Abstract

This paper gives an overview of the contribution of water footprint (WF) studies on water for energy relationships. It first explains why water is needed for energy, gives an overview of important water energy studies until 2009, shows the contribution of Hoekstra’s work [...] Read more.

This paper gives an overview of the contribution of water footprint (WF) studies on water for energy relationships. It first explains why water is needed for energy, gives an overview of important water energy studies until 2009, shows the contribution of Hoekstra’s work on WF of energy generation, and indicates how this contribution has supported new research. Finally, it provides knowledge gaps that are relevant for future studies. Energy source categories are: 1. biofuels from sugar, starch and oil crops; 2. cellulosic feedstocks; 3. biofuels from algae; 4. firewood; 5. hydropower and 6. various sources of energy including electricity, heat and transport fuels. Especially category 1, 3, 4, 5 and to a lesser extent 2 have relatively large WFs. This is because the energy source derives from agriculture or forestry, which has a large water use (1,2,4), or has large water use due to evaporation from open water surfaces (3,5). WFs for these categories can be calculated using the WF tool. Category 6 includes fossil fuels and renewables, such as photovoltaics and wind energy and has relatively small WFs. However, information needs to be derived from industry. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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12 pages, 1696 KiB

Open AccessEditor’s ChoiceReview

The Water Footprint of Global Food Production

by Mesfin M. Mekonnen and Winnie Gerbens-Leenes

Water 2020, 12(10), 2696; https://doi.org/10.3390/w12102696 - 26 Sep 2020

Cited by 99 | Viewed by 31971

Abstract

Agricultural production is the main consumer of water. Future population growth, income growth, and dietary shifts are expected to increase demand for water. The paper presents a brief review of the water footprint of crop production and the sustainability of the blue water [...] Read more.

Agricultural production is the main consumer of water. Future population growth, income growth, and dietary shifts are expected to increase demand for water. The paper presents a brief review of the water footprint of crop production and the sustainability of the blue water footprint. The estimated global consumptive (green plus blue) water footprint ranges from 5938 to 8508 km³/year. The water footprint is projected to increase by as much as 22% due to climate change and land use change by 2090. Approximately 57% of the global blue water footprint is shown to violate the environmental flow requirements. This calls for action to improve the sustainability of water and protect ecosystems that depend on it. Some of the measures include increasing water productivity, setting benchmarks, setting caps on the water footprint per river basin, shifting the diets to food items with low water requirements, and reducing food waste. Full article

(This article belongs to the Special Issue In Memory of Prof. Arjen Y. Hoekstra)

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