Revisiting irrigation efficiency before restoring ancient irrigation canals in multi-functional, nature-based water systems

In the Middle Ages, Muslims introduced communal water management in Iberian Peninsula. Some irrigation systems of medieval origin are still operation mountainous areas Southern Spain. Snowmelt runoff is diverted during spring from high-altitude streams into contoured recharge ditches that convey to high infiltration (shallow aquifers). This regulates and delays discharge main river, which downstream flow diverted, late summer, supply terraces fields on river plains. The Busquístar ditch its scheme comprise one these ancient systems. 1) To characterize system, source regulation, users' association, multi-functionality, quality as a nature-based solution for security. 2) review efficiency concept applied restoration systems, taking account their ecosystem services. i) Semi-structured interviews with stakeholders evaluate system perceptions multi-functionality; ii) field surveys description riparian flora; iii) satellite imagery quantifying vegetation; iv) balance computation. Crop production function but additional services creation landscape biodiversity. Eight plant communities were distinguished along ditch. measured at head 23 July 3 September 2017 represented 14 50% mean September, respectively. first bifurcation was about half head, revealing proportion filtered 6470-m long conveyance reach. remaining then 4 branches 3140-m distribution reach proportionally irrigable area each branch. Return flows estimated two measuring dates considering crop evapotranspiration. highly dependent uses considered beneficial scale analysis, field, entire or watershed. study revealed integrated approach behind traditional article proposes allows reconciling character current responding needs emerging export horticulture area. • Irrigation Ancient provide addition agricultural production. functionalities an Spain characterized. usual can be misleading revised reconcile gains social environmental nature.