Engineering Commons^™

Global Monthly Water Scarcity: Blue Water Footprints Versus Blue Water Availability, Arjen Y. Hoekstra, Mesfin Mekonnen, Ashok K. Chapagain, Ruth E. Mathews, Brian D. Richter

Daugherty Water for Food Global Institute: Faculty Publications

Freshwater scarcity is a growing concern, placing considerable importance on the accuracy of indicators used to characterize and map water scarcity worldwide. We improve upon past efforts by using estimates of blue water footprints (consumptive use of ground- and surface water flows) rather than water withdrawals, accounting for the flows needed to sustain critical ecological functions and by considering monthly rather than annual values. We analyzed 405 river basins for the period 1996–2005. In 201 basins with 2.67 billion inhabitants there was severe water scarcity during at least one month of the year. The ecological and economic consequences of increasing …

The Water Footprint Of Humanity, Arjen Y. Hoekstra, Mesfin Mekonnen

Daugherty Water for Food Global Institute: Faculty Publications

This study quantifies and maps the water footprint (WF) of humanity at a high spatial resolution. It reports on consumptive use of rainwater (green WF) and ground and surface water (blue WF) and volumes of water polluted (gray WF). Water footprints are estimated per nation from both a production and consumption perspective. International virtual water flows are estimated based on trade in agricultural and industrial commodities. The global annual average WF in the period 1996–2005 was 9,087 Gm3 ∕y (74% green, 11% blue, 15% gray). Agricultural production contributes 92%. About one-fifth of the global WF relates to production for export. …

The Green, Blue And Grey Water Footprint Of Crops And Derived Crop Products, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Abstract. This study quantifies the green, blue and grey water footprint of global crop production in a spatially-explicit way for the period 1996–2005. The assessment improves upon earlier research by taking a high-resolution approach, estimating the water footprint of 126 crops at a 5 by 5 arc minute grid. We have used a grid-based dynamic water balance model to calculate crop water use over time, with a time step of one day. The model takes into account the daily soil water balance and climatic conditions for each grid cell. In addition, the water pollution associated with the use of nitrogen …

National Water Footprint Accounts: The Green, Blue And Grey Water Footprint Of Production And Consumption. Volume 1: Main Report, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

This study quantifies and maps the water footprints of nations from both a production and consumption perspective and estimates international virtual water flows and national and global water savings as a result of trade. The entire estimate includes a breakdown of water footprints, virtual water flows and water savings into their green, blue and grey components. The main finding of the study can be summarized as:

The global water footprint in the period 1996-2005 was 9087 Gm3/yr (74% green, 11% blue, 15% grey). Agricultural production contributes 92% to this total footprint.

About one fifth of the global water footprint relates …

National Water Footprint Accounts: The Green, Blue And Grey Water Footprint Of Production And Consumption, Volume 2: Appendices, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Contents

Appendix I. The water footprint of national production (Mm³/yr)

Appendix II. Virtual-water flows related to trade in crop, animal and industrial products, per country (Mm³/yr)

Appendix III. International virtual-water flows per product category (Mm³/yr)

Appendix IV. National water saving related to trade in agricultural and industrial products per country (Mm³/yr)

Appendix V. Global water saving related to trade in agricultural and industrial products, per product (Mm³/yr)

Appendix VI. The average water footprint per ton of commodity per country, weighted based on origin (WF* in m³/ton)

Appendix VII. …

The Green, Blue And Grey Water Footprint Of Farm Animals And Animal Products. Volume 2: Appendices, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Contents

Appendix I: Feed conversion efficiencies – in kg of feed (dry mass) per kg of output – per animal category and region

Appendix II: Estimated consumption of feed per animal category and world region (10³ ton dry mass/yr)

Appendix III. Estimated consumption of feed per production system and world region (10³ ton dry mass/yr)

Appendix IV. Drinking and service water footprint per animal

Appendix V. Water footprint of animals and animal products (m³/ton). Period 1996-2005

The Challenges Of Wastewater Irrigation In Developing Countries, M. Qadir, D. Wichelns, L. Raschid-Sally, Peter G. Mccornick, P. Drechsel, A. Bahri, P. S. Minhas

Daugherty Water for Food Global Institute: Faculty Publications

The volume of wastewater generated by domestic, industrial, and commercial sources has increased with population, urbanization, improved living conditions, and economic development. The productive use of wastewater has also increased, as millions of small-scale farmers in urban and peri-urban areas of developing countries depend on wastewater or wastewater-polluted water sources to irrigate high-value edible crops for urban markets, often as they have no alternative sources of irrigation water. Undesirable constituents in wastewater can harm human health and the environment. Hence, wastewater irrigation is an issue of concern to public agencies responsible for maintaining public health and environmental quality. For diverse …