The scale of the colossus and the thirst of the crops
The Alqueva reservoir constitutes the largest hydro-agricultural and water regulation reservoir in the Iberian Peninsula, featuring a total storage capacity of 4,150 cubic hectometres and a useful volume of 3,150 cubic hectometres, with over 1,100 kilometres of shoreline, according to official 2016 data from the Portuguese Environment Agency. This monumental infrastructure was designed to transform the agricultural and economic landscape of a vast region in the south of the national territory, affecting dozens of municipalities.
However, the practical use of this body of water has changed profoundly over the years. According to the 2024 campaign report released by the Empresa de Desenvolvimento e Infraestruturas do Alqueva, the area registered for irrigation in the Alqueva Multi-Purpose Scheme reached 116,562 hectares. Of that impressive total, 74,059 hectares were occupied by olive groves and 24,607 hectares by nuts, mainly almond groves.
These two intensive monocultures thus represent more than 84% of all irrigated land managed by the public infrastructure. In terms of gross volume, EDIA recorded a total distribution of 455.2 cubic hectometres of water in 2024, of which irrigated agriculture absorbed 382 cubic hectometres, equating to 84% of the global volume, while public consumption remained at 9.2 cubic hectometres and industry at 1.2 cubic hectometres.
Land ownership structure and corporate pressure
To understand the local impact of these numbers, it is necessary to look at the structure of agricultural property in the Alentejo region before and after the massive arrival of irrigation. According to the 2019 Agricultural Census published by Statistics Portugal in 2020, the average size of agricultural holdings stood at 60.99 hectares of Utilized Agricultural Area, a value that contrasts very sharply with the mainland Portugal average, set at 13.85 hectares, and the European Union average of 28 Member States, situated at around 16.6 hectares.
Between the years 2009 and 2019, INE data show that the total number of agricultural holdings in Alentejo suffered a drop of 7.62%, falling from 41,720 to 38,541 operational units. In the opposite direction, strictly corporate agricultural companies doubled in the same time period, coming to manage 36.7% of all Utilized Agricultural Area at the national level.
Added to this is the fact that, according to data advanced in 2022 by the Association of Olive Growers and Olive Oil Mills of Portugal, around six large agro-industrial groups and international investment funds came to hold or manage more than 65% of the large irrigated olive grove holdings located in the area of direct influence of the public project.
Energy costs and flow regulation
The daily management of water resources faces severe technical constraints related to the energy required to move the water. According to EDIA's 2024 accounts report published in 2025, the distribution and pressurization of water in the primary and secondary networks consumes an average of 0.45 kilowatt-hours of electricity for every cubic metre pumped, generating a direct and linear dependence between the final price paid by the farmer and wholesale energy prices in markets.
To curb unmanageable rises associated with the energy crisis, the Government determined in May 2023 an extraordinary limitation on the tariff increase for irrigation water, capping it at a maximum of 24%, which translated to a rise of 0.01 euros per cubic metre and avoided the original technical proposal stemming from energy costs that anticipated a drastic increase of 140%, according to records from the Ministry of Agriculture and Food from 2023.
In parallel, to discipline consumption in a basin under heavy pressure, EDIA implemented the Annual Water Use Plan starting from the 2023 campaign. This instrument began to impose a maximum authorized volume per crop based on technical reference allocations from the Center for Technology and Irrigation Operations, determining the automatic interruption of supply to any holding exceeding the fixed regulatory limit.
Public investments and award criteria
The State's financial effort in expanding secondary irrigation networks continues to intensify through new blocks approved in 2024. Through Ordinance No. 387/2024/2, the Government authorized EDIA to incur an expense of 88,880,467.14 euros destined for the execution of the Reguengos de Monsaraz Hydraulic Circuit and respective blocks under the National Irrigation Program, published in the Diário da República.
In the same vein, Ordinance No. 411/2024/2 authorized EDIA to advance with the infrastructure development of the Moura Block, structuring a new gravity irrigation network covering an area of 1,200 hectares from the Caliços reservoir, according to official dispatches issued in 2024 by the competent government offices.
As a regulatory counterpoint to protect smaller-scale producers, EDIA introduced preferential award criteria in the public rustic plot lease tenders promoted in November 2023 for 36 plots and in August 2024 for 9 plots, directly benefiting holders of the Family Farming Statute, Young Farmers, and operators in Organic Production Mode, according to the company's official notices from 2023.
The democratization narrative versus scarcity data
The most frequent intuitive and institutional reading maintains that the large public infrastructure of Alqueva democratized access to water and saved the Alentejo agricultural sector in the face of climate change, allowing any local producer to irrigate their fields. However, this premise directly collides with the statistical reality found in the holdings and with the official planning of the river basin.
The 3rd Cycle of the Guadiana River Basin Management Plan, approved by Council of Ministers Resolution No. 62/2024 of the Portuguese Environment Agency, unequivocally points out that agricultural demand represents more than 80% of total water abstractions in the basin and that diffuse pressures originating from agriculture and livestock negatively affect more than 50% of water bodies, whose ecological status is below good.
Furthermore, in the years of severe water scarcity recorded in interconnected developments, farmers with contracts under precarious title located outside formal blocks suffered drastic supply cuts reaching 100%, safeguarding solely the water allocations for definitive irrigators integrated into the official perimeter, as detailed in a 2021 technical report by the Directorate-General for Agriculture and Rural Development.
The economic impact on the land and the future of the municipalities
For those who live and work in the 47 municipalities of Alentejo, the arrival of irrigation and the exponential valorization of the soil have generated a profound economic and social transformation. The Environmental Impact Studies of EFMA irrigation blocks, such as those of São Pedro-Baleizão and Roxo-Sado prepared in 2010 by the Portuguese Environment Agency through SIAIA, already indicated that conversion to irrigation would elevate the commercial value of the land by several orders of magnitude.
In daily economic practice, this abrupt inflation of soil prices triggered the block acquisition of historical estates by large agro-industrial groups and institutional funds, given the recognized financial incapacity for reinvestment and purchase by small tenant farmers and traditional family farmers of the region.
To mitigate this concentration trend, the Management Authority of the Rural Development Program applied over 675 million euros by 2020 across 4,000 projects nationwide, having even blocked applications for the installation of new olive groves in the area of direct influence of the Alqueva irrigation system in order to halt the unregulated expansion of intensive monoculture, according to the official 2020 balance sheet of PDR 2020.