Fig. 1: Spatial characteristics of modelled tanker water markets across Jordan in 2015.

a,c,d, The JWM-T determines the set of feasible sales between consumer and agricultural agents in Jordan’s 89 subdistricts that maximizes their private surplus (d) by simulating consumers’ residual tanker water demands (a) and agricultural opportunity costs (c). b, Illustration of the road distances taken into account by the model to calculate transport costs between the well and town locations shown in a and c. Results are from a baseline JWM-T simulation for 2015. d, Large sales quantities along with moderately high prices occur around the central Amman–Zarqa agglomeration and Irbid, higher prices around Ajloun, comparatively large sales quantities around Mafraq and hardly any tanker water sales in Aqaba. Prices around Amman–Zarqa and Irbid are explained by high demands (a). Amman–Zarqa is the main population centre. In Irbid, the arrival of Syrian refugees in 2011–2015 has strained local piped water supply capacities. High local opportunity costs (c) and long mountain roads impeding access to affordable tanker water (b) explain the higher prices around Ajloun. By contrast, the area around Mafraq, with its large number of wells and low opportunity costs, exhibits particularly low tanker water prices. As a result, some subdistricts around Mafraq show higher sales quantities than those around Ajloun, despite having comparable demands. Tanker water sales expand south to the towns and villages between Karak and Maan. At the southern border of Jordan, the coastal city of Aqaba receives continuous piped water supply from the Disi Aquifer and thus purchases almost no tanker water. The model and its data sources are described in Methods. All monetary values are in constant 2015 US$. Map data include World Hillshade tiles by Esri, USGS, Airbus DS, NGA, NASA, CGIAR, N Robinson, NCEAS, NLS, OS, NMA, Geodatastyrelsen, Rijkswaterstaat, GSA, Geoland, FEMA, Intermap and the GIS user community. Credit: basemaps in a–d, ESRI and contributors; roads in b, OpenStreetMap contributors.