Resource Dynamo: A GIS model to match urban nutrient supply with agricultural demand.

Buildings in cities represent potential point sources of human excreta-derived nutrients, while agricultural land in (peri)urban areas demand nutrients as fertilizers. Here we present a new geographic information system (GIS)-based modelling tool, Resource Dynamo, that optimizes the allocation of excreta-derived nutrients from buildings in cities to nearby agricultural fields. The model minimizes the number of supply sites needed to match the demand by prioritizing sites with the highest nutrient supply, i.e. the hotspots. Furthermore the model delineates exact transport routes between the discrete supply and demand sites. The transport distances are minimized as transport costs are a key factor for economic viability of nutrient management. The high resolution of the model allows it to function as a decision-support tool for bringing cyclic nutrient management into practice. To disclose the potential of the model, we used it to match phosphorus supply in human-derived urine with phosphorus demands from agricultural fields within the municipality of Amsterdam on a temporal scale of 1 year. • Geospatial transport distance optimization between nutrient supply and demand sites. • In Amsterdam, 38% of phosphorus supply from human urine covers agricultural demand. • Average transport distances between supply and demand sites were under 11 km. • Visualization with Resource Dynamo can support decision-making towards nutrient cycling. [ABSTRACT FROM AUTHOR]