Irrigation in Portugal and climate change

19:00 Tuesday 28 May




Alberto Freitas (Portugal) 1; Cláudia Brandão (Portugal) 1; António Campeã Da Mota (Portugal) 1

1 - Direção-Geral de Agricultura e Desenvolvimento Rural

Currently, the global demand for water is estimated to be around 4 600 km3/year, and it is estimated that this will increase from 20% to 30%, reaching a volume between 6 000 and 5 500 km3/year by 2050 (World Water Development Report, WWDR, 2018).

World water use has increased by six times over the past 100 years and continues to grow steadily, with world demand for agricultural output expected to increase by about 60% by 2025 (WWDR, 2018). Considering the prevailing management practices, the intensification of production will involve increasing mechanical interventions on the ground and the use of agrochemicals, energy and water. These factors will contribute to the reduction of terrestrial biodiversity. This impact and the need for more land and more water can be largely avoided if the intensification of production involves the improvement of environmental services.

Global climate change is one of the challenges of the 21st century that consists in the development of a planet in a sustainable way, which considers the existence of finite and sensitive natural resources. It is therefore essential to be able to adapt to the new climate paradigm, reducing its impact on the environment and avoiding the reduction of areas with habitable conditions.

In Portugal the impact of climate change will likely increase the need for irrigation of crops and reduce water availability, due to the change of hydro-meteorological regime. In this context, there has been an adjustment in the demand-supply binomial in the agricultural sector, resulting in a significant reduction of water uses (-48%): 6.54 to 3.3 km3/year (National-Water-Plan, 2002, 2016).

It will therefore be essential to continue to increase the water storage capacity and promote efficient water management, reducing losses in irrigation network (distribution) and an optimization of the use of water (farmer). In order to reduce water consumption, Portugal is implementing the National Irrigation Program, which includes the modernization and rehabilitation of existing public agricultural facilities exploitations and the construction of reservoirs, and the promotion of capacity-building for the use of efficient production processes, suitable with environmental services.

Simultaneously, the supply guarantees of the hydraulics agricultural infrastructures are being reassessed, since the assumptions supporting its design have been changed, namely the existence of new and other consumptive uses and the probable decrease in water availability, forcing to implement measures to mitigate the potential losses. This evaluation is being carried out, and it is possible to present some results.