The 2007 report of the Intergovernmental Panel on Climate Change (IPCC)
projected with high confidence that the conditions (drought and high
temperatures) in the Southern Europe will worsen. It stated that this region that
includes Portugal is already vulnerable and will experience a reduction in water
availability, hydropower potential and crop yield and productivity. The evidence
of such conditions have already struck Portugal when during the 2004-2005
hydrological year experienced one of its worst droughts in decades. Between
June to September 2005, the whole country was classified as experiencing
sever to extreme drought according to the Palmer Drought Severity Index
(PDSI). At the same time, Portugal was developing its new Water Law based on
the requirements of the so called Water Framework Directive of the European
Union. Its Article 11 states that one of the basic and required measures is to
promote efficient and sustainable use of water. As a consequence of these two
factors, the Portuguese Government adopted a series of adaptation measures,
one of them being a ten year National Program for Efficient Use of Water.
This paper will present this program in its irrigation water use, analyse its
effective efficiency and discuss advantages and disadvantages of the portfolio
of measures that are being considered. Until recently, classical efficiency
defined as the ratio of the beneficial output to input was mostly used to calculate
irrigation water efficiency. But in this study, the effective efficiency (EE) indicator
was used which is defined as the ratio of beneficial output to the effective
demand. Beneficial output is essentially net evapotranspiration.
The preliminary results show an EE of about 60% corresponding to an effective
water demand of about 6.6 billion cubic meter per year. This quantity of water is
more than 85% of total water demand in Portugal. The cost of supplying this
amount of water is estimated to be about half a billion Euros per year resulting
in about 200 millions of Euros of losses. Some specific results of two river
basins namely the international Douro River Basin will be presented in this
paper. The Program sets a goal of improving the EE to 65% to be achieved in
10 years by 2015. Four areas of intervention were proposed to achieve this
goal: information and education, training and technical help, legislation and
normalisation, and Measurement and conversion of equipments of water use