TY - JOUR

T1 - Robust vegetation parameterization for green roofs in the epa stormwater management model (SWMM)

AU - Iffland, Ronja

AU - Förster, Kristian

AU - Westerholt, Daniel

AU - Pesci, María Herminia

AU - Lösken, Gilbert

PY - 2021/3

Y1 - 2021/3

N2 - In increasingly expanding cities, roofs are still largely unused areas to counteract the neg-ative impacts of urbanization on the water balance and to reduce flooding. To estimate the effect of green roofs as a sustainable low impact development (LID) technique on the building scale, different approaches to predict the runoff are carried out. In hydrological modelling, representing vegetation feedback on evapotranspiration (ET) is still considered challenging. In this research article, the focus is on improving the representation of the coupled soil–vegetation system of green roofs. Relevant data to calibrate and validate model representations were obtained from an existing field campaign comprising several green roof test plots with different characteristics. A coupled model, utilizing both the Penman–Monteith equation to estimate ET and the software EPA stormwater management model (SWMM) to calculate the runoff, was set up. Through the application of an automatic calibration procedure, we demonstrate that this coupled modelling approach (Kling–Gupta efficiency KGE = 0.88) outperforms the standard ET representation in EPA SWMM (KGE = −0.35), whilst providing a consistent and robust parameter set across all green roof configurations. Moreover, through a global sensitivity analysis, the impact of changes in model parameters was quantified in order to aid modelers in simplifying their parameterization of EPA SWMM. Finally, an improved model using the Penman–Monteith equation and various recommendations are presented.

AB - In increasingly expanding cities, roofs are still largely unused areas to counteract the neg-ative impacts of urbanization on the water balance and to reduce flooding. To estimate the effect of green roofs as a sustainable low impact development (LID) technique on the building scale, different approaches to predict the runoff are carried out. In hydrological modelling, representing vegetation feedback on evapotranspiration (ET) is still considered challenging. In this research article, the focus is on improving the representation of the coupled soil–vegetation system of green roofs. Relevant data to calibrate and validate model representations were obtained from an existing field campaign comprising several green roof test plots with different characteristics. A coupled model, utilizing both the Penman–Monteith equation to estimate ET and the software EPA stormwater management model (SWMM) to calculate the runoff, was set up. Through the application of an automatic calibration procedure, we demonstrate that this coupled modelling approach (Kling–Gupta efficiency KGE = 0.88) outperforms the standard ET representation in EPA SWMM (KGE = −0.35), whilst providing a consistent and robust parameter set across all green roof configurations. Moreover, through a global sensitivity analysis, the impact of changes in model parameters was quantified in order to aid modelers in simplifying their parameterization of EPA SWMM. Finally, an improved model using the Penman–Monteith equation and various recommendations are presented.

KW - EPA SWMM

KW - Green roof

KW - Parameter optimization

KW - Penman–Monteith

KW - Runoff

KW - Sedum

UR - http://www.scopus.com/inward/record.url?scp=85099965230&partnerID=8YFLogxK

U2 - 10.3390/hydrology8010012

DO - 10.3390/hydrology8010012

M3 - Article

AN - SCOPUS:85099965230

VL - 8

JO - Hydrology

JF - Hydrology

IS - 1

M1 - 12

ER -