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Conserving green and blue water in the WANA region

Abstract:

The WANA region is characterized by water scarcity with 14 countries ranked in the top 20 water scarce countries, with less than 500 m3 of renewable water/year/capita. Despite this current situation, water availability per capita will be severely reduced due to climate change and the increase in water demand. On the other hand, woodlands cover only 13.1 % of the region in average, moreover, most countries (14) have very low cover rate (less than 4 %). In this context of water scarcity, the blue and green water approach has raised much interest over the last years, especially in dry areas, for analyzing water balance. The green water (evaporation and transpiration) is needed to sustain ecosystem processes and the goods and services they provide, while the blue water (surface runoff and groundwater recharge) plays a paramount role on water supply to urban populations, industry and irrigated agriculture. In such circumstances of conflicts and trade-offs, integrating hydrological, ecological and socio-economic management is a key approach towards sustainability. Mainly, the effects of the land use change on water resources and their distribution among stakeholders should be analyzed and economic instruments should be introduced when establishing a watershed management plan in a water-constrained environment.