Independent Validation of the SWMM Green Roof Module

Green roofs are a popular Sustainable Drainage Systems (SuDS) technology. They provide multiple benefits, amongst which the retention of rainfall and detention of runoff are of particular interest to stormwater engineers. The hydrological performance of green roofs has been represented in various models, including the Storm Water Management Model (SWMM). The latest version of SWMM includes a new LID green roof module, which makes it possible to model the hydrological performance of a green roof by directly defining the physical parameters of a green roof’s three layers. However, to date, no study has validated the capability of this module for representing the hydrological performance of an extensive green roof in response to actual rainfall events. In this study, data from a previously-monitored extensive green roof test bed has been utilised to validate the SWMM green roof module for both long-term (173 events over a year) and short-term (per-event) simulations. With only 0.357% difference between measured and modelled annual retention, the uncalibrated model provided good estimates of total annual retention, but the modelled runoff depths deviated significantly from the measured data at certain times (particularly during summer) in the year. Retention results improved (with the difference between modelled and measured annual retention decreasing to 0.169% and the Nash-Sutcliffe Model Efficiency (NSME) coefficient for per-event rainfall depth reaching 0.948) when reductions in actual evapotranspiration due to reduced substrate moisture availability during prolonged dry conditions were used to provide revised estimates of monthly ET. However, this aspect of the model’s performance is ultimately limited by the failure to account for the influence of substrate moisture on actual ET rates. With significant differences existing between measured and simulated runoff and NSME coefficients of below 0.5, the uncalibrated model failed to provide reasonable predictions of the green roof’s detention performance, although this was significantly improved through calibration. To precisely model the hydrological behaviour of an extensive green roof with a plastic board drainage layer, some of the modelling structures in SWMM green roof module require further refinement

Between the legacy of nation-state and forces of globalisation : Turkey’s management of mixed migration flows

Turkey, at the crossroads of Europe, Middle East and Asia, has confronted with mounting pressures of mixed migration flows in recent decades. This paper aims to explore Turkey’s contemporary approach to migration management by focusing on the adoption of the country’s first comprehensive immigration law (Law on Foreigners and International Protection) and the signing of the readmission agreement with the European Union in 2013. This incorporates an analysis of both policy continuities and changes in migration management in Turkey, while also providing an understanding of the interplay between internal and external factors, namely internationalisation and Europeanisation processes and the responsiveness of domestic actors to such pressures. The paper argues that migration policies driven solely by state-centric concerns are becoming increasingly inefficient in responding to the challenges caused by interlinked pressures of globalisation and multi-layered migratory flows. As Turkey’s role as a transit and receiving country grows, issues of international migration, and irregular migration in particular, are becoming dynamic topics in defining its role in a globalised world and as well as the trajectory of its relations with the EU

Characterization of infiltration capacity of permeable pavements with porous asphalt surface using cantabrian fixed infiltrometer

Porous asphalt is used in Permeable Pavement Systems, but it is sensitive to surface clogging, which leads to a loss in its infiltration capacity. Test methods based on the use of permeable pavement models, which are manufactured in a laboratory and assessed under different clogging conditions, such as slope, rain, and runoff, have been widely applied to the study of permeable pavements with concrete blocks but not to the study of porous bituminous mixtures. The Cantabrian Fixed (CF) Infiltrometer has been used for the study of porous asphalt with void percentages between 20 and 33%. Three clogging scenarios were studied: 1) newly placed surface, 2) surface with an average maintenance level, and 3) clogged surface. Each clogging scenario was tested with five different slopes: 0, 2, 5, 8, and 10% and three repetitions. The direct rainfall simulation was produced by five lines of bubblers over the 0.25 - m 2 piece, and the runoff was simulated by one perforated pipe over a plastic ramp at the beginning of the surface. From the analysis of the results, it was concluded that a suitable design of a porous bituminous mixture, with a void percentage that increases with depth, along with surface brushing are enough to ensure and maintain a good infiltration capacity. Finally, an empirical, conservative model for estimating the porous asphalt infiltration capacity, based on the length, the clogging scenario, and the surface slope, is proposed