Author(s): Jose Vargas B. ; Carlos Padilla; Alex Schwarz
Linked Author(s): José Vargas Baecheler
Keywords: Biofilter; WQCV; Urban runoff
Abstract: Among the alternative techniques of urban drainage, bioretention system stands out, which consist of a small vegetated basin compose of horizontal layers. This system consist in a small vegetated basin compose of horizontal layers with specific functions that has for objective to give treatment to the urban run-off generated by rain water, before his discharge to a receptor body, by a combination of a series of chemical and biochemical processes. This study aims to determine the capture volume of a biofilter, which corresponds to the storage limited for his depth of detention and his infiltration area. From the analysis of pluviographs records of the Carriel Sur station in Concepción (Chile) between 1989 and 2010, using the WQ-COSM statistical software, developed by the Urban Watersheds Research Institute (UWRI) on Denver, US. This software, through a continue simulation; using the Rational Method and a mass balance, determine the volume of capture necessary to dimension the system. The approach adopted in this study is to capture the smaller rain events, often responsible for washing the surface of drainage and cause a great impact on water quality of the receiving bodies, even more than extreme events. For the determination of the volume of capture, the WQ-COSM model required parameters like the runoff coefficient of the basin; the time of emptying, that will determine the rate of treated water that leaves the system; the time of the separation of events, equal of the dry period between rain events necessary to assume the independence among them; and the surface storage, that also include the losses because interception and infiltration processes during a storm, amount that establish if a precipitation event generates surface run-off. The last two mentioned parameters are essential in this study because the value of these variables determines the characteristics of the series of rain events that are analyzed, even so they criterion of determination are too wide and have been little studied. Because of that, was made an analysis of sensitivity that concluded that the volume of capture of the biofilter it' s too sensitive to these parameters, so it' s recommended to estimate specific values for every single basin.
Year: 2015