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Eight of the current sizing and design methods proposed for bioretention facilities were evaluated for rainfall runoff and snow storage volumes for a costal cold climate in Trondheim, Norway. The RECARGA bioretention infiltration model was used to compare the performance of the methods using 30 months of observed data from a pilot scale bioretention box. The surface areas, total ponding time, number and duration of overflow events, and snow storage volumes were compared. It was found that even in a costal cold climate with several intermittent melt cycles die snow storage requirements were an important design parameter, and if more than 25% of the total snow volume should stored this became the deciding design parameter.

Eight of the current sizing and design methods proposed for bioretention facilities were evaluated for rainfall runoff and snow storage volumes for a costal cold climate in Trondheim, Norway. The RECARGA bioretention infiltration model was used to compare the performance of the methods using 10 months of observed data from a pilot scale bioretention box. The surface areas, total ponding time, number and duration of overflow events, and snow storage volumes were compared. It was found that even in a costal cold climate with several intermittent melt cycles the snow storage requirements were an important design parameter, and if more than 25% of the total snow volume should stored this became the deciding design parameter. Godkänd; 2007; Bibliografisk uppgift: Evaluation de l'application des methodes existantes de dimensionnement de procédé de bioretention aux climates froids et en présence des neiges provenant de la chaussée; 20070926 (marvik)

The overall goal of this project is to contribute to education and training in urban drainage in cold climate. If engineers are to handle year round urban drainage in cold climate, they must have education and training within urban drainage in cold climate conditions. The project, Education and Training Laboratory on Urban Drainage in Cold Climate (ETL-UD-CC) was implemented at Department of Hydraulic & Environmental Engineering, (NTNU). ETL-UD-CC is based on internet connection between Risvollan urban hydrological field laboratory (RUHFL) and Risvollan urban hydrological station (RUHS). RUHS is designed for year round measurements in cold climate. RUHS is made online. This make real time data and the urban hydrological database back to 1986 available in the classroom. The students can then rub model calibration and verification in the classroom using real time and historical urban hydrological data. The key parameters in cold climate are the snow water equivalent (SWE) and the snow covered area (SCA). The urban snow melt modeling is still in the early stage. The field measurements and the real time data make it possible for the students to make decisions on what to do in operating the urban drainage system and to simulate the effects on the urban drainage system year round. The student enjoy staying outside the classroom and the feedbacks are promising The authors believe that TEL-UD-CC may contribute to education and training in urban drainage in cold climate.

This paper describes an experimental field work setup for testing the performance of bioretention areas in a cold climate setting at Risvollan urban hydrological station in Trondheim, Norway. Bioretention focuses on water retention, peak flow reduction, and water quality improvement with respect to heavy metals and sediments. However, in colder climates the performance of bioretention areas are to a large extent unknown. The most problematic with winter conditions are the many interchanged snow and rainfall events, creating rain-on-snow events, resulting in ice formation, then melting and often refreezing. This causes blockage of stormwater inlets and elevated risk of flooding. The focus of this paper will be on the hydraulic retention properties of the system. The performance of the bioretention area will be evaluated based on peak runoff reduction and detention capabilities. The results so far indicate promising results with respect to detention capabilities also during typical coastal winter conditions. The outflow from the bioretention area was compared to runoff from an equal size impervious area. The average reduction in peak flow rates compared with impervious surface runoff was 49 %. The actual reduction will vary dependent on pre event