Water management in southeastern Spain, the Alpujarras region, is a fascinating topic. The local communities maintain very precise irrigation ditches ("acequia

Water management in southeastern Spain, the Alpujarras region, is a fascinating topic. The local communities maintain very precise irrigation ditches ("acequias de careo") midway along the mountains. During the months of rainfall and snowmelt, the water flowing along these ditches is soaked into the ground up to the point where the ditch ends because all the water has been absorbed underground. Months later, the water from each such acequia springs out clean and fresh at a specific location further down the mountain, while the weather is dry, and can be used for irrigation at a time that would be otherwise impossible. The absolute differences with Iran's qanats are: zero infrastructure to develop underground, as all the water circulation happens along natural underground waterways, and clean, fresh water thanks to the layers of slow ground filtration. It is my understanding that this system was put in place during the Muslim period of the Alpujarras, based on knowledge from Middle-Eastern dynasties whose people relocated to Spain. That seems to match the "Islamic Golden Age" period described in the article