title: Modelling the impact of retention-detention units on sewer surcharge and peak and annual runoff reduction.
abstract: Stormwater management using water sensitive urban design is expected to be part of future drainage systems. This paper aims to model the combination of local retention units, such as soakaways, with subsurface detention units. Soakaways are employed to reduce (by storage and infiltration) peak and volume stormwater runoff; however, large retention volumes are required for a significant peak reduction. Peak runoff can therefore be handled by combining detention units with soakaways. This paper models the impact of retrofitting retention-detention units for an existing urbanized catchment in Denmark. The impact of retrofitting a retention-detention unit of 3.3 m³/100 m² (volume/impervious area) was simulated for a small catchment in Copenhagen using MIKE URBAN. The retention-detention unit was shown to prevent flooding from the sewer for a 10-year rainfall event. Statistical analysis of continuous simulations covering 22 years showed that annual stormwater runoff was reduced by 68-87%, and that the retention volume was on average 53% full at the beginning of rain events. The effect of different retention-detention volume combinations was simulated, and results showed that allocating 20-40% of a soakaway volume to detention would significantly increase peak runoff reduction with a small reduction in the annual runoff.
authors: Technical University of Denmark, Department of Environmental Engineering, Miljøvej, bygning 113, 2800 Kgs. Lyngby, Denmark E-mail: lulo@env.dtu.dk.
authors: Luca
authors: L
authors: Locatelli
authors: Orbicon, Ringstedvej 20, 4000 Roskilde, Denmark.
authors: Søren
authors: S
authors: Gabriel
authors: DHI, Agern Allé 5, 2970 Hørsholm, Denmark.
authors: Ole
authors: O
authors: Mark
authors: Technical University of Denmark, Department of Environmental Engineering, Miljøvej, bygning 113, 2800 Kgs. Lyngby, Denmark E-mail: lulo@env.dtu.dk.
authors: Peter Steen
authors: PS
authors: Mikkelsen
authors: Technical University of Denmark, Department of Environmental Engineering, Miljøvej, bygning 113, 2800 Kgs. Lyngby, Denmark E-mail: lulo@env.dtu.dk.
authors: Karsten
authors: K
authors: Arnbjerg-Nielsen
authors: Orbicon, Ringstedvej 20, 4000 Roskilde, Denmark.
authors: Heidi
authors: H
authors: Taylor
authors: University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
authors: Britta
authors: B
authors: Bockhorn
authors: Orbicon, Ringstedvej 20, 4000 Roskilde, Denmark.
authors: Hauge
authors: H
authors: Larsen
authors: DHI, Agern Allé 5, 2970 Hørsholm, Denmark.
authors: Morten Just
authors: MJ
authors: Kjølby
authors: Orbicon, Ringstedvej 20, 4000 Roskilde, Denmark.
authors: Anne Steensen
authors: AS
authors: Blicher
authors: Technical University of Denmark, Department of Environmental Engineering, Miljøvej, bygning 113, 2800 Kgs. Lyngby, Denmark E-mail: lulo@env.dtu.dk.
authors: Philip John
authors: PJ
authors: Binning
mesh_terms: D002947:Cities; D003718:Denmark; D008962:Models, Theoretical; D011891:Rain; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements
chemical_list: D012722:Sewage