More detailed information on ViWA

The role of COPERNICUS-SENTINEL data in ViWA

The economic evaluation of virtual water flows

In the past the economic analyses of the use of scarce water resources have concentrated on the efficiency or inefficiency of local rules of water allocation. In parallel, the importance of international trade for the exchange of virtual water and the resulting possible reduction of local water scarcity was analyzed. Both the analytical and the action level nevertheless were not previously linked. First attempts explicitly examine the economic importance of water with the help of CGE-models (Beritella, et al. (2007), Calzadilla et al. (2010), Taheripur et al. (2013)), however, limited to the agricultural sector. In these, the scarcity of water is represented, at a high level of regional aggregation (GTAP AEZ (2008)), by shadow prices arising from the difference between the yields of irrigated to non-irrigated agriculture. In a study of the implications of water scarcity and economic growth, the relevance of other sectors (households, energy production, industry, environment) is emphasized (OECD 2014).

The project combines the high resolution Water-Energy-Food-Nexus monitoring concept described above with detailed CGE-simulations of the world market with special emphasis on agricultural commodities and the role of water, its scarcity, its efficiecy in the use for agriculture and the competition for water between different economic sectors. Thereby the project identifies and quantifies in unprecedented detail the international trade in virtual water. The coupling of monitoring data with CGE-simulations also makes it possible to model and derive scarcity measures for regional water resources. Scarcity of water resources can be defined in various dimensions, as competing uses between crops and between regions within a watershed, between sectors and between countries. These aspects are examined in the model compound by deriving shadow prices for water use from the econometric analyzes for water productivity. Using the shadow price of water in different uses regional inefficiencies of water use within a country as well as in the distortions in international trade will be identified.

These activities provide the conceptual framework for the analysis of scenarios for an efficient and sustainable water use (link to: Analysis of scenarios for sustainable water use.).

Sustainability assessment and Governance of water resources and SDGs

The real and virtual water flows and their governance are examined in light of the water-related SDGs. For this purpose a sustainability assessment is carried out based on the monitoring approach.  The project will address numerous proposed UN-SDG-indicators  (UN 2015). It will specifically  contribute to quantify the proposed global indicators No. 13,15,16,48, the national indicator 2.11 and it will contribute to quantify global indicators 83 and 85. It specifically identifies and evaluates with the involvement of stakeholders trade-offs in achieving the SDGs food security (SDG 2), water (SDG 6), bioenergy (SDG 7), climate (SDG 13) and protection of ecosystems (SDG 15). This contributes to the refinement and application of existing indicator systems to monitor progress of SDGs. From these results water shortage areas with unsustainable water use (hot spots) and areas with abundance of water (cold spots) are delineated globally based on the trade-offs between potentially affected area units and available water / energy / land use. 

Trade-offs between ecosystem services and agricultural production (food security, bioenergy) are analyzed for different ecosystem types using the simulated changes in water flows and yields in the representative watersheds with the aim to classify sensitivities (e.g. organic matter, water-dependency) and assignments (e.g. case studies on the Red List of Ecosystems, IUCN) by means of a GIS-based “environmental risk assessment”. The water supply situation is analyzed in high resolution with indicators of Vörosmarty (2010), data from 3.1 and global population data (LandScan (2015), 1km²) and validated using FAO and Aquastat NEESPI data. The result represents areas and residents affected by different degrees of a lack of water.

For the hot-spots of unsustainable water use “spatial problems of fit” are determined (asymmetry between the spatial extent of ecological processes and political decision spaces). They are the starting points for case studies (literature based) on potential institutional obstacles to a sustainable and efficient water use (target 5).

Analysis of scenarios for sustainable water use.

The outcome of the high-resolution monitoring system for water-related SDGs (link), the integrated economic evaluation of virtual water flows (link) and the sustainability assessment and governance of water resources and SDGs (link) are continuously discussed with stakeholders. Together scenarios are formulated and implemented in ViWA to identify effective and efficient control instruments for a more sustainable and efficient water management that go beyond the ones that are already identified, which are: 1) investigate the vulnerability of water use by looking at the natural climate variability represented by the El Nino event 2015/16 as well as the years 2017 and 2018. They are compared and analyzed specifically with regard to hot-spots of water shortage and the impact on water use and economic feedback effects on the global agricultural markets. 2) scenarios to simulate options for a globally efficient and sustainable water management. For this purpose we assume that local water use efficiency is changed by improved farming practices. They are introduced into the model compound similar to the approach in Mauser et al. (2015). 3) similar methods are used to simulate the effectiveness and efficiency of control instruments, such as usage restrictions of fossil groundwater or water pricing. The scenarios analyses make it possible to identify and highlight the potential benefits and trade-offs of different regulatory instruments for water use.

All project partners, including the stakeholders, participate in the review and evaluation of the results of the scenarios. Here, e.g. the potential yield increases that go along with increased water use efficiency and the welfare effects of a more efficient water use and appropriate management options are demonstrated and the economic distribution effects of sustainable water use in intra-regional and inter-regional level are assessed. In addition trade-offs between different SDGs related to water are discussed and evaluated based on results.