Physical water scarcity metrics for monitoring progress towards SDG target 6.4: An evaluation of indicator 6.4.2 "Level of water stress".

Target 6.4 of the recently adopted Sustainable Development Goals (SDGs) deals with the reduction of water scarcity. To monitor progress towards this target, two indicators are used: Indicator 6.4.1 measuring water use efficiency and 6.4.2 measuring the level of water stress (WS). This paper aims to identify whether the currently proposed indicator 6.4.2 considers the different elements that need to be accounted for in a WS indicator. WS indicators compare water use with water availability. We identify seven essential elements: 1) both gross and net water abstraction (or withdrawal) provide important information to understand WS; 2) WS indicators need to incorporate environmental flow requirements (EFR); 3) temporal and 4) spatial disaggregation is required in a WS assessment; 5) both renewable surface water and groundwater resources, including their interaction, need to be accounted for as renewable water availability; 6) alternative available water resources need to be accounted for as well, like fossil groundwater and desalinated water; 7) WS indicators need to account for water storage in reservoirs, water recycling and managed aquifer recharge. Indicator 6.4.2 considers many of these elements, but there is need for improvement. It is recommended that WS is measured based on net abstraction as well, in addition to currently only measuring WS based on gross abstraction. It does incorporate EFR. Temporal and spatial disaggregation is indeed defined as a goal in more advanced monitoring levels, in which it is also called for a differentiation between surface and groundwater resources. However, regarding element 6 and 7 there are some shortcomings for which we provide recommendations. In addition, indicator 6.4.2 is only one indicator, which monitors blue WS, but does not give information on green or green-blue water scarcity or on water quality. Within the SDG indicator framework, some of these topics are covered with other indicators.

Green-blue water system innovations for upgrading of smallholder farming systems--a policy framework for development.

Rainfed agriculture and other depletion of water by green flows have as yet an untapped potential for improving livelihoods in semi-arid areas through income and food security. A vivid evidence of this is seen in the fact that, although working full time on food production, majority of smallholder farmers are frequently affected by shortage of food or famines. At the same time enough examples exist to show that productivity of labor, water and land under rainfed farming can be doubled or even trebled through proper land management and improved agronomic inputs supported by modest investments to reduce impacts of dry spells. However, these shining examples remain small 'islands of success' across the entire semi-arid areas. Farmers have not adopted these systems due to poor ratio of benefit to costs brought about by inadequate development or complete lack of food trade among the rural areas. This paper argues that there is a need for policy, strategic and programmatic frameworks which facilitate integrated management of land, water and markets. For this kind of strategy to work, a local market for food should be ensured to absorb at competitive prices the surplus produced by farmers in years of good rains. This will promote wealth creation and asset building among the poor in semi-arid areas. A food-exchange "futures" mechanism based on the principle of virtual water trade is proposed as a basis for achieving this objective.

Workshop 4 (synthesis): green/blue water management options for crop production.

There is a huge untapped potential for increases in crop yields from green water flows. By better land use management of the whole drainage basin we can get more out of green water without compromising blue water flows.

Making the best of climatic variability: options for upgrading rainfed farming in water scarce regions.

Coping with climatic variability for livelihood security is part of everyday life for rural communities in semi-arid and dry sub-humid savannas. Water scarcity caused by rainfall fluctuations is common, causing meteorological droughts and dry spells. However, this paper indicates, based on experiences in sub-Saharan Africa and India, that the social impact on rural societies of climatically induced droughts is exaggerated. Instead, water scarcity causing food deficits is more often caused by management induced droughts and dry spells. A conceptual framework to distinguish between manageable and unmanageable droughts is presented. It is suggested that climatic droughts require focus on social resilience building instead of land and water resource management. Focus is then set on the manageable part of climatic variability, namely the almost annual occurrence of dry spells, short 2-4 week periods of no rainfall, affecting farmer yields. On-farm experiences in savannas of sub-Saharan Africa of water harvesting systems for dry spell mitigation are presented. It is shown that bridging dry spells combined with soil fertility management can double and even triple on-farm yield levels. Combined with innovative systems to ensure maximum plant water availability and water uptake capacity, through adoption of soil fertility improvement and conservation tillage systems, there is a clear opportunity to upgrade rainfed farming systems in vulnerable savanna environments, through appropriate local management of climatic variability.

Hydrosolidarity intergenerational challenges: long-term commitment for long-term issues.

The year 2000 Young Professionals Seminar focused on long-term intergenerational challenges. Water related problems are symptoms of complex and ultimately societal problems linked to human behaviour, political support and managerial and institutional structures. Although integrated water resources management is presented as a solution, it is not always well understood, and can create a sense of hopelessness among professionals. To make it operational requires long-term commitments among various professionals and the involvement of new actors. A number of key topics crystallised as needing further attention, including ethical dimensions in policy making, the development of a framework for a "Future Generation Impact Assessment" (FGIA), and efforts to achieve true dialogue among stakeholders. Young water professionals must become more involved in political processes and take active part in institutional changes. Such engagement will require changes in the working environment facing many young professionals that causes frustration due to inefficient and conservative hierarchical structures and the lack of transparency.

Green water security for the food makers of tomorrow: windows of opportunity in drought-prone savannahs.

The largest remaining biophysical water challenge is whether there is enough fresh water to sustain global food production and service natural ecosytems. Focussing on the drought-prone savannahs and small-scale farming, this paper argues that the crucial resource is vapour flow, not "blue" water, and there are grounds for optimism if resource management can be improved.