Seasonal variations in infiltration in cold climate raingardens - a case study from Norway

Abstract

Winter infiltration in cold climate raingardens is a key function for proper year-round function. The Modified Phillip-Dunne Infiltrometers (MPD) procedure was used for measuring the infiltration capacity. The research was based on a case study approach, combining field measurements and simulations. The results were compared to results from the literature about raingardens in cold climates. Saturated hydraulic conductivity (Ksat) provides a measure of infiltration capacity and is recommended to be >10 cm/h in cold climate raingardens. The results show a seasonal variation in Ksat, from 1 cm/h (October) to 0.05 cm/h (November-April). Simulation of a raingarden in Trondheim, show a decrease in infiltrated inflow from 75 % to 25 % in the raingarden when Ksat goes from 1 cm/h to 0.05 cm/h. This paper presents a winter adaptation of the MPD-method.