Water shortage is a growing concern and in response to this many countries are developing national water plans in an attempt to allocate water more effectively. In the Middle-East, where water is extremely scarce these water plans are considered as a means to improved water resources planning, but the plans are often based on limited information and data and are always very much focused on water in rivers and groundwater, rather than considering all the components of the water balance in the broader hydrological context. Weaknesses in these water plans often are:

1. Actual water use from irrigated areas is often assumed to be similar to water supplied.
2. There is an emphasis on increasing the so-called water efficiency rather than aiming at increasing water productivity.
3. Water consumption (=evaporation and transpiration) from natural vegetation or bare soils is not considered.
4. Groundwater recharge is poorly understood and based only on groundwater observation wells.
5. Net groundwater use, and to some extent surface water abstraction estimates are based on estimates of pumping hours and pump capacity rather than on actual abstractions.
6. Analysis is based on average conditions.
7. Water plans can be a reflection of preferred policies rather than based on unbiased analyses.

These issues make the estimated water consumption and the, from this derived, potential water allocations often unrealistic. It is however possible by using advanced remote sensing techniques to tackle most of the issues mentioned here. High resolution rainfall observations, accurate evapotranspiration estimates, and biomass production can be obtained at an unprecedented accuracy using remote sensing. Even changes in deep groundwater using changes in gravity fields can be monitored from remote sensing nowadays. Especially the high spatial coverage makes these remote sensing observations a unique product to support the national water plans.

Results based on completed studies in Tunisia, Egypt and Saudi-Arabia using advanced remote sensing techniques, are compared to information used in the national water plans of the three countries. This study assess to what extent these remote sensing observations can support the development of national water plans, improve the understanding of resource availability, better assess where water is consumed, and identify where losses are avoidable.

Publicaciones relacionadas

• 2009 - FutureWater Report 80Droogers, P., C. Perry, W.W. Immerzeel. 2009. Application of Remote Sensing in National Water Plans: Demonstration cases for Egypt, Saudi-Arabia and Tunisia. FutureWater Report 80X

  Application of Remote Sensing in National Water Plans: Demonstration cases for Egypt, Saudi-Arabia and Tunisia

  Droogers, P., C. Perry, W.W. Immerzeel