Mapping irrigation efficiency in large urban green areas

This study presents a novel method for controlling and monitoring irrigation of urban green areas based on Geographical Information Systems (GIS). The proposed procedure was applied to the Spanish Valdebebas Urban Development, located in Madrid, which comprises 18 ha occupied by urban parks irrigated by subsurface drip irrigation fully automated. Its irrigation network conveys water to 67 different irrigation units, irrigating very heterogeneous plants typology. The GIS model considered the smallest irrigation unit, as the pixel size and it was fed with the information on: discharging flow, irrigated area and irrigation times of each irrigation unit. The study was performed with data from the three irrigation seasons from 2017 to 2019. Likewise, daily information from the weather station located at the urban development, used for the irrigation network operation, was also incorporated into the GIS. The results showed the spatial and temporal variability of the garden coefficients (and water needs) and the water use efficiency. The study also estimate the evolution of irrigation rates and water use efficiency indices under three different climate change forecasting scenarios (namely Representative Concentration Pathways– RCP–45, RCP 6 and RCP85). This method can assist technicians and irrigation managers to make better decisions on operating the parks’ irrigation network.