Assessing the effects of four SUDS scenarios on combined sewer overflows in Oslo, Norway: evaluating the low-impact development module of the Mike Urban model

Abstract

<jats:title>Abstract</jats:title> <jats:p>Paved surfaces, increased precipitation intensities in addition to limited capacity in the sewer systems, cause a higher risk of combined sewer overflows (CSOs). Sustainable drainage systems (SUDS) offer an alternative approach to mitigate CSO by managing the stormwater locally. Seven SUDS scenarios, developed based on the concept of effective impervious area reduction, have been implemented in the Grefsen catchment using the Mike Urban model. This study evaluated the hydrological performance of two SUDS controls (i.e. green roof (GR) and rain garden (RG)) modules of the model and the effect of the SUDS scenarios on the CSOs using event-based and continuous simulations. The Nash–Sutcliffe efficiency (NSE) along with flow duration curves (FDCs) has been used for evaluating the model performance. Event-based evaluations revealed the superior performance of the RG in reducing CSOs for larger precipitation events, while GRs were proven to have beneficial outcomes during smaller events. The study illustrated another way of assessing the continuous simulations by employing the FDCs. The FDCs were assessed against a discharge threshold at the outlet (which authorities can set as design criteria) of the catchment in terms of the extent, each scenario reduced occurrence and duration of outflow that invokes flow in the overflow pipe.</jats:p>

Hydrological performance of lined permeable pavements in Norway

“…Simulated outflows from the two models were used to derive FDCs. The derivation of FDCs was similar to the study of Hernes et al (2020). Firstly, outflow values were ranked from highest to lowest.…”

“…They applied FDCs to evaluate different scenarios of SUD implementation in a catchment. Similarly, Hernes et al (2020) applied FDCs to investigate the performance of different SUD scenarios, and they concluded the suitability of FDC as a practical measure to evaluate the hydrological performance of SUDs. Using the FDC to evaluate the performance of PP was found to be limited to few studies in the literature (Fassman & Blackbourn 2010;Brown et al 2012;Winston et al 2018), and no study was found to apply the FDC for LPP systems.…”

Predicting Discharges in Sewer Pipes Using an Integrated Long Short-Term Memory and Entropy A-TOPSIS Modeling Framework

“…For instance, in Norway, sewers comprising of CSSs and stormwater drains account for 35,900 km and 15,700 km, respectively, of the entire sewer system [2]. Rapid urbanization combined with increased precipitation due to climate change and low investments in the rehabilitation of aging CSSs have resulted in the increased incidence of combined sewer overflows (CSOs) in Norway [3][4][5]. A study by Nilsen et al [5] revealed a significant relationship between the volume of CSOs in the sewer network in Oslo and flood events.…”

Method for assessing the impact of rainfall depth on the stormwater volume in a sanitary sewage network

“…Efficient sewage network management depends not only on accurate information on the momentary sewer flows but also the future expected flows, which enables to predict and avert emergencies [9,10]. In addition, the possibility of predicting the hydraulic load of WWTP during extreme rainfalls enables to devise the algorithms for optimization of the treatment process [11].…”