Infiltrating into the paved garden - a functional evaluation of parcel imperviousness in terms of water retention efficiency

Domestic gardens have been found to contribute between 16-36% of the total urban area in different cities. They play a prominent role in ecosystem services including water retention and local climate regulation. We developed a tool that evaluates the rainwater retention efficiency of parcels (REP). This tool took inspiration from the Biotope Area Factor (BAF), which uses intuitive weighting parameters. Quantitative runoff values obtained from scientific literature form the base of REP, which was incorporated in a GIS to simplify the input. REP and BAF values were compared for a sample of detached, semi-detached and terraced houses.