Green roofs are an effective tool to reduce the quantity of stormwater runoff in urban areas. The performance of a green roof (GR) in reducing runoff is indeed influenced by the climate and it ranges from 60% to 100% depending on the local environmental conditions as shown by several studies (Mobilia et all. 2015, Mentens et al., 2006, Teemusk & Mander, 2007). Modelling of evapotranspiration is strongly affected by the weather condition, too. Evapotranspiration may directly act on moisture content in the layer of the green roof so on its ability to retain water after rainfall events. For these reasons, in time, many authors have developed different models for prediction of the hydraulic behaviour of vegetated covers entailing the use of this term (Stovin et al., 2013,Locatelli et al., 2014, Poë et al., 2015). The aim of this study is to introduce a simple conceptual model based on soil water balance equations. Evapotranspiration represents an important term of the water balance, hence the need to consider the actual evapotranspiration (AET) because the potential one could lead to incorrect evaluation of the system efficiency. AET is calculated from potential evapotranspiration (PET) estimates using two models: API-model and AA-model. The proposed model is then calibrated and validated using measurement data collected from an extensive green roof site near Bernkastel-Kues (Germany). The goodness of Fit (GOF) of simulated runoff values to the set of observations is evaluated calculating three indices such as the root-mean-square errors (RMSEs), the averages of absolute percentage errors (AAPEs) and the relative percentage errors (RPEs).
INCLUDING ACTUAL EVAPOTRANSPIRATION FOR GREEN ROOF MODELLING AT AN EXPERIMENTAL
MOBILIA, MIRKA;LONGOBARDI, Antonia;
2016
Abstract
Green roofs are an effective tool to reduce the quantity of stormwater runoff in urban areas. The performance of a green roof (GR) in reducing runoff is indeed influenced by the climate and it ranges from 60% to 100% depending on the local environmental conditions as shown by several studies (Mobilia et all. 2015, Mentens et al., 2006, Teemusk & Mander, 2007). Modelling of evapotranspiration is strongly affected by the weather condition, too. Evapotranspiration may directly act on moisture content in the layer of the green roof so on its ability to retain water after rainfall events. For these reasons, in time, many authors have developed different models for prediction of the hydraulic behaviour of vegetated covers entailing the use of this term (Stovin et al., 2013,Locatelli et al., 2014, Poë et al., 2015). The aim of this study is to introduce a simple conceptual model based on soil water balance equations. Evapotranspiration represents an important term of the water balance, hence the need to consider the actual evapotranspiration (AET) because the potential one could lead to incorrect evaluation of the system efficiency. AET is calculated from potential evapotranspiration (PET) estimates using two models: API-model and AA-model. The proposed model is then calibrated and validated using measurement data collected from an extensive green roof site near Bernkastel-Kues (Germany). The goodness of Fit (GOF) of simulated runoff values to the set of observations is evaluated calculating three indices such as the root-mean-square errors (RMSEs), the averages of absolute percentage errors (AAPEs) and the relative percentage errors (RPEs).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
