A global, spatially-explicit assessment of irrigated croplands influenced by urban wastewater flows

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dc.creatorThebo, Anne Louise
dc.creatorDrechsel, Pay
dc.creatorLambin, Eric
dc.creatorNelson, Kara
dc.date2017-07-01
dc.date2017-07-04T15:36:00Z
dc.date2017-07-04T15:36:00Z
dc.date.accessioned2026-06-27T18:31:07Z
dc.descriptionWhen urban areas expand without concomitant increases in wastewater treatment capacity, vast quantities of wastewater are released to surface waters with little or no treatment. Downstream of many urban areas are large areas of irrigated croplands reliant on these same surface water sources. Case studies document the widespread use of untreated wastewater in irrigated agriculture, but due to the practical and political challenges of conducting a true census of this practice, its global extent is not well known except where reuse has been planned. This study used GIS-based modeling methods to develop the first spatially-explicit estimate of the global extent of irrigated croplands influenced by urban wastewater flows, including indirect wastewater use. These croplands were further classified by their likelihood of using poor quality water based on the spatial proximity of croplands to urban areas, urban wastewater return flow ratios, and proportion of wastewater treated. This study found that 65% (35.9 Mha) of downstream irrigated croplands were located in catchments with high levels of dependence on urban wastewater flows. These same catchments were home to 1.37 billion urban residents. Of these croplands, 29.3 Mha were located in countries with low levels of wastewater treatment and home to 885 million urban residents. These figures provide insight into the key role that water reuse plays in meeting the water and food needs of people around the world, and the need to invest in wastewater treatment to protect public health.
dc.formatapplication/pdf
dc.identifierhttps://hdl.handle.net/10568/82641
dc.identifier.urihttp://hdl.handle.net/123456789/158240
dc.languageen
dc.publisherIOP Publishing
dc.rightsOpen Access
dc.sourceThebo, A.L.; Drechsel, P.; Lambin, E.; Nelson, K. 2017. A global, spatially-explicit assessment of irrigated croplands influenced by urban wastewater flows. Environmental Research Letters.12(7):20p.
dc.subjectindirect water reuse
dc.subjectwater quality
dc.subjectgis
dc.subjectspatial analysis
dc.subjectreturn flow ratio
dc.subjecturban sanitation
dc.subjectwastewater treatment
dc.subjectirrigated land
dc.subjectfarmland
dc.subjecturban wastes
dc.subjectwater reuse
dc.subjectsanitation
dc.subjectsurface water
dc.subjectirrigated farming
dc.subjectdownstream
dc.subjectcatchment areas
dc.subjectpublic health
dc.subjectcase studies
dc.titleA global, spatially-explicit assessment of irrigated croplands influenced by urban wastewater flows
dc.typeJournal Article

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