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The largest city in Benin, West Africa (Cotonou), is reliant upon groundwater for its public water supply. This groundwater is derived from the Godomey well field which is located approximately 5 Km north of the coast of the Atlantic Ocean and in close proximity to Lake Nokoue—a shallow lake containing water with elevated concentration of chloride and other elements. Historical data indicate increased chloride concentration in a number of wells nearest to the lake, with unknown contribution from groundwater encroachment from the coastal area. Hence, there is substantial interest in better characterizing this groundwater system for the purpose of determining appropriate management practices and degree of sustainability. Among the efforts attempted to date are a series of numerical models ranging from assessment of flow to a recent effort to include density-dependent transport from the lake. In addition, substantial field characterization has been pursued including assessment of shallow water chemistry along the region of the coastal lagoon and border of the lake, characterization of hydraulic response to pumpage in the aquifer system, estimation of the distribution of electrical resistivity with depth along the coastal lagoons, and installation of multi-level piezometers at seven locations in the lake. When integrated across methods, these numerical and field results indicate that the lake remains a primary concern in terms of a source of salinity in the aquifer. Further, the coastal region appears to be more complex than previously suggested and may represent a future source of salt-water encroachment as suggested by current presence of saline waters at relatively shallow depths along the coast. Finally, hydraulic testing suggests that both natural and pumping-based fluctuations in water levels are present in this system. Substantial additional characterization and modeling efforts may provide a significantly greater understanding of the behavior of this complex groundwater system and, thereby, an improved ability to manage the potential for negative impacts from salt-water and anthropogenic contaminants entering this sole source of fresh water for southern Benin.

Water scarcity, land use conversion and cultural and ecosystem changes threaten the way of life for traditional irrigation communities of the semi-arid southwestern United States. Traditions are strong, yet potential upheaval is great in these communities that rely on acequia irrigation systems. Acequias are ancient ditch systems brought from the Iberian Peninsula to the New World over 400 years ago; they are simultaneously gravity flow water delivery systems and shared water governance institutions. Acequias have survived periods of drought and external shocks from changing economics, demographics, and resource uses. Now, climate change and urbanization threaten water availability, ecosystem functions, and the acequia communities themselves. Do past adaptive practices hold the key to future sustainability, or are new strategies required? To explore this issue we translated disciplinary understanding into a uniform format of causal loop diagrams to conceptualize the subsystems of the entire acequia-based human-natural system. Four subsystems are identified in this study: hydrology, ecosystem, land use/economics, and sociocultural. Important linkages between subsystems were revealed as well as variables indicating community cohesion (e.g., total irrigated land, intensity of upland grazing, mutualism). Ongoing work will test the conceptualizations with field data and modeling exercises to capture tipping points for non-sustainability and thresholds for sustainable water use and community longevity.

The necessity of Urban Water Cycle Services (UWCS) adapting to future stresses calls for changes that take sustainability into account. Megatrends (e.g. population growth, water scarcity, pollution and climate change) pose urgent water challenges in cities. In a previous paper, a set of indicators, i.e., the City Blueprint has been developed to assess the sustainability of UWCS (Van Leeuwen et al., Wat Resour Manage 26:2177–2197, 2012). In this paper this approach has been applied in 9 cities and regions in Europe (Amsterdam, Algarve, Athens, Bucharest, Hamburg, Reggio Emilia, Rotterdam, Oslo and Cities of Scotland) and in 2 African cities in Angola (Kilamba Kiaxi) and Tanzania (Dar es Salaam). The assessments showed that cities vary considerably with regard to the sustainability of the UWCS. This is also captured in the Blue City Index (BCI), the arithmetic mean of 24 indicators comprising the City Blueprint (Van Leeuwen et al., Wat Resour Manage 26:2177–2197, 2012). Theoretically, the BCI has a minimum score of 0 and a maximum score of 10. The actual BCIs in the 11 cities studied varied from 3.31 (Kilamba Kiaxi) to 7.72 (Hamburg). The BCI was positively correlated with the Gross Domestic Product (GDP) per person, the ambitions of the local authorities regarding the sustainability of the UWCS, the voluntary participation index (VPI) and all governance indicators according to the World Bank. The study demonstrated that the variability in sustainability among the UWCS of cities offers great opportunities for short-term and long-term improvements, provided that cities share their best practices.

Groundwater irrigation for smallholder farmers in Sub-Saharan Africa is growing in extent and importance. This growth is primarily driven spontaneously by the farmers themselves, spurred by improved access to low-cost technologies for pumps and drilling services as well as market opportunities for produce. This paper presents a review of the current status and knowledge of the prospects and constraints for sustainable and pro-poor groundwater irrigation in Sub-Saharan Africa. Further unlocking the potential of groundwater irrigation for smallholders will require better integrated approaches, simultaneously addressing groundwater-access constraints as well as enabling factors.

This paper develops an integrated modeling approach combined with a top-down dynamic computable general equilibrium (CGE) model and a bottom-up bio-economic model (BEM) to study the economic impact of a total water use control policy in the Heihe river basin, northwestern China. The integrated CGE-BEM model is regionally disaggregated with a variety of crops and livestock, and includes the responses of farmers and consequent feedback effects in the regional economic system. The results show that under the total water use control scenario, the water use structure is changed and water use efficiency is improved. The total water use control policy has limited negative impact on the regional economic growth with only a slightly lower growth rate of 13.38% compared with a growth rate of 14% by 2020 under a business as usual water use scenario. However, the total water use control policy has significant negative impacts on several sectors, especially agriculture and food processing. It is expected cropping systems will change through a replacement of water-intensive crops with water-efficient crops. Farmers’ incomes will decrease by 3.14%. In order to alleviate farmers’ income loss and deal with water use conflicts across different sectors and regions, the promotion of migration of surplus labor from agriculture to non-agricultural sectors and the improvement of water use efficiency in agriculture are needed.

This paper deals with the construction, decomposition and comparison of water footprint time series in 40 countries and one aggregate macro-region, in the period 1995–2009. The analysis of the different “footpaths” allows us to investigate the possible causes behind the time evolution of water footprints in the various countries. We notice that the physical and economic impact of economic growth on water resources has been significantly lower than what it could have been, for several reasons. First, both production and consumption patterns are shifting away from water-intensive goods. Second, a large part of consumed water is actually not blue water, susceptible to alternative uses. Finally, we do not find strong evidence of gains in the economic productivity of water (dollars per water unit) in many countries, but we do find evidence of indirect efficiency gains, related to a composition of factors in the production processes.

A growing world population, changing consumption patterns and climate change are affecting water demands, water scarcity and water quality worldwide, while at present, few companies are incorporating good water stewardship. In order to create awareness on this issue and provide an incentive for companies to improve the water performance in their operations and supply chain, a method for ranking companies based on their water transparency has been developed. The method consists of a checklist that can be completed on the basis of information from annual reports, sustainability reports and websites of companies. This is the first time a ranking of companies regarding water transparency has been carried out. Results show that there are large differences in transparency between and within sectors and that companies are reporting more about their operations than their supply chain.