The document shows how Alentejo is strengthening drought management by combining hydrological planning, irrigation modernization, and a strong commitment to digital tools to monitor, plan, and optimize irrigation management. It is particularly addressed to hydro-agricultural schemes and farms that need to adapt to a climate change context with less rainfall, higher temperatures, and increasingly frequent and intense droughts.
Climatic context and irrigation in Alentejo
The text begins by analyzing the effects of climate change in Mediterranean Portugal: rising temperatures, decreasing and irregular rainfall, higher evapotranspiration, and worsening water deficits, all directly affecting irrigation requirements and agricultural productivity. Irrigation is presented as a strategic activity to reduce production system vulnerability, as long as it goes hand in hand with efficient water use and increased storage capacity.
The document highlights the importance of southern Portugal’s hydro-agricultural systems and estimates collective irrigation storage capacity in Alentejo at over 5,500 hm³, indicating the scale of systems to be managed under drought conditions. It also stresses the need to reassess the reliability of water supply for these systems under new climatic patterns and water demand trends.
Water governance and drought plans
The text outlines the European and Portuguese legal framework: the Water Framework Directive and the Water Law organize management by river basin districts and establish principles such as the social, environmental, and economic value of water, as well as the need for integrated planning. The Portuguese Environment Agency (APA) acts as the national water authority coordinating river basin management plans, while the DGADR serves as the National Irrigation Authority, overseeing irrigation associations.
The Plan for Prevention, Monitoring, and Contingency in Drought Situations defines the concepts, indicators, and tools needed to manage both agrometeorological and hydrological droughts. It establishes four alert levels—normal, pre-alert, alert, and emergency—and sets out structural and non-structural measures for each level. Key measures include agricultural planning adapted to water availability, promotion of efficient use, reuse of wastewater, and enhanced monitoring through the Drought Surveillance and Alert Program.
Irrigation water use efficiency
The report distinguishes strategies at both collective irrigation scheme scale and farm/plot scale. For infrastructure, priorities include modernizing open channels into pressurized networks, building storage reservoirs, and improving the maintenance and operation of pumps and mixed networks, which during drought shift from on-demand irrigation to scheduled rotations.
At farm level, recommendations include efficient irrigation systems (drip, micro-sprinkler, well-designed sprinkler), periodic technical inspection of equipment (by bodies such as COTR), water storage and reuse, and controlled deficit irrigation adapted to crop-sensitive stages. Complementary agronomic practices include improving soil structure and organic matter, using cover crops, selecting less water-demanding species and varieties, and adjusting sowing and harvesting calendars.
Digital solutions for water scarcity
A central section focuses on how digital technologies enhance the effectiveness of previous measures, for both collective irrigation systems and individual farms. It recommends maintaining georeferenced crop inventories using GIS and remote sensing, enabling prioritization of perennial crop survival and water distribution planning in line with contingency plans and network efficiency.
The text presents tools to estimate irrigation needs based on reference evapotranspiration and crop coefficients, integrated into applications such as “Calendário de Rega” and the PARE platform, which generate allocation recommendations adapted to local climate, crop, and irrigation system. It also describes IoT sensor networks in soil and plants, satellite and drone-based remote sensing, digital meters and manometers, and telecontrol systems allowing real-time monitoring, leak detection, and operational adjustment.
Digital twins and future prospects
The document concludes by highlighting the potential of advanced management systems such as predictive models based on artificial intelligence and digital twins of irrigation schemes. Using historical sensor data, climate records, flow meters, and crop mapping, these models can accurately forecast short-term water needs and simulate different operating scenarios under scarcity. This predictive capacity enables simultaneous optimization of water and energy use, supports fairer and more transparent allocation decisions, and strengthens the resilience of Alentejo’s irrigation sector against an increasingly demanding climate.
The document is available here (in Portuguese): Strategies for water scarcity management in Alentejo
