Water for human use: climate and development




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Water is a critical resource for human development. It is an essential resource in itself, but is also required for many human activities. Agriculture is the biggest user of freshwater resources (approx.. 70%, (World Water Assessment Programme, 2009)). Energy and industrial production require water, especially for cooling purposes. Other important livelihood aspects are also indirectly affected by sufficient and adequate water supply.

Different user groups require access to water in different quantities and access has to be granted in a user specific way. We quantify the adequacy of water resources for different user groups in three case study regions. Climatic and population pressures are taken into account, using climate scenarios and population projection. The results give important information on how to best adapt and improve water provision for different users to improve livelihood conditions, taking into account climate change and sustainable development.



Figure 1: Important determinants of water adequacy for the main sectors of water use

Figure 1 outlines the most important aspects of water adequacy for livelihoods. The municipal (domestic) sector requires the least overall water resource, but adequate access to high quality water infrastructure and water quality are absolutely essential. Most of the used water goes into agricultural production. Here, water resource availability and security of supply play the most important role, while water quality is an additional aspect. Industrial /energy water access is mainly determined by the water availability and quality. However, the concrete requirements differ strongly depending on the type of production and are very site specific.

The results show that in the three case study countries water resources are not necessarily the limiting factor for adequate water access, but infrastructure and water quality play an important role. Water resources are a limiting factor mainly in densely populated areas and population growth in these regions over the coming decades may lead to situations of scarcity there.

Method

Fuzzy logic was used to aggregate all input factors into an integrated indicator of water adequacy for human livelihoods (Figure 2).



Figure 2: Outline of the fuzzy aggregation process to calculate the adequacy of water resources.



Data Sources

Sector Indicator Variable Resolution Source
Municipal Access Source of drinking water Subnational values (Regions) MEASURE DHS
Water quality Phosphorus loading
Nitrogen loading
Sediment loading
Organic loading
Mercury deposition
Pesticide loading 		0.5° Grid Vörösmarty et al (2010)
Industrial Water quality Sediment loading
Thermal alteration 		0.5° Grid Vörösmarty et al (2010)
Agricultural Water quality Soil salinization0.5° Grid Vörösmarty et al (2010)
Security of supply Dam density
Area equipped for irrigation 		0.5° Grid
0.083° Grid 		Vörösmarty et al (2010)
AquaSTAT
Water availability Runoff 0.5° Grid LPJmL
Population data Subnational data


Results were calculated using water data from LPJmL, a Dynamic Global Vegetation and Water Balance Model. We calculated results for a baseline period (1981-2010) and a short-term future scenario (2011-2040) using two climate models (HadGEM2-ES and GFDL-ESM2M) and two RCPs (2.6 and 8.5).

References

World Water Assessment Programme. (2009). The United Nations World Water Development Report 3: Water in a Changing World. Paris and London: UNESCO and Earthscan.