Quite A Lot in Commons: Two Adaptation Climate Strategies in the Greater Madrid Area

This research presents two projects, Collaborative Systems and On the Rocks, situated in Madrid's metropolitan area—an arid highland home to six million people. Historically, the region relied on two primary water sources: the River Tagus, which supported agriculture, and the Guadarrama Mountains, which supplied urban water needs.

The River Tagus and its tributaries suported agriculture through communal irrigation systems (acequias de careo) introduced during Moorish times. These watercourses infiltrated water into the soil, enabling cultivating high water-demand crops like strawberries, fruit trees, alongside the olive groves. However, deforestation, lack of maintenance, and high evaporation rates have rendered these systems ineffective, causing a critical drop in water tables.

Urban expansion since the 19th century forced the introduction of a separate water supply sourced from newly built reservoirs in the Guadarrama Mountains, flooding entire valleys emaciated after supplying the region for centuries with stone, timber and dairy products. Though this system supported Madrid’s population boom in the 20th century, global warming today exacerbates water shortages, combining reduced precipitation, increased evaporation, and wildfire-related deforestation. Summer water restrictions loom closer each year.

The two projects tackle these issues by reinterpreting dehesas—traditional Spanish agroforests that function as water buffers, slowing down evaporation and promoting reforestation. The project Collaborative Systems revives the acequias de careo, for irrigation, while the project On the Rocks repurposes abandoned quarries as water reservoirs. Both emphasise engaging communities through governance structures that balance clear rules with adaptability, ensuring the sustainability of these interventions.

These projects highlight the interdependence of cities and their surrounding regions and the necessity of practical collaborative efforts to combat climate change.