Modelling the Role of SuDS Management Trains in Minimising Flood Risk, Using MicroDrainage

Craig Lashford,Matthew Blackett,Susanne Charlesworth,Frank Warwick

doi:10.3390/w12092559

Abstract

This novel research models the impact that commonly used sustainable drainage systems (SuDS) have on runoff, and compare this to their land take. As land take is consistently cited as a key barrier to the wider implementation of SuDS, it is essential to understand the possible runoff reduction in relation to the area they take up. SuDS management trains consisting of different combinations of detention basins, green roofs, porous pavement and swales were designed in MicroDrainage. In this study, this is modelled against the 1% Annual Exceedance Potential storm (over 30, 60, 90, 120, 360 and 720 min, under different infiltration scenarios), to determine the possible runoff reduction of each device. Detention basins were consistently the most effective regarding maximum runoff reduction for the land they take (0.419 L/s/m2), with porous pavement the second most effective, achieving 0.145 L/s/m2. As both green roofs (20.34%) and porous pavement (6.76%) account for land that would traditionally be impermeable, there is no net-loss of land compared to a traditional drainage approach. Consequently, although the modelled SuDS management train accounts for 34.86% of the total site, just 7.76% of the land is lost to SuDS, whilst managing flooding for all modelled rainfall and infiltration scenarios.

Highlights

Maximum runoff reduction in comparison with conventional piped drainage was achieved for all Sustainable drainage systems (SuDS) components when used just in conjunction with swales, for example, detention basins and swales
Whilst research has shown the benefits of integrating SuDS, in a management train, there remain a number of barriers to their wider implementation [6]
This study has presented a novel approach to understand the specific benefits that popular SuDS techniques can have on minimizing peak runoffs, utilizing the UK industry standard drainage modelling tool, MicroDrainage

Summary

Introduction

The risk of flooding is increased when conventional piped based systems are not adapted to manage the intensified stormwater runoff associated with both increased impermeable surfaces and a changing climate. Sustainable drainage systems (SuDS), provide an alternative approach to managing stormwater and flooding [1]. SuDS mimic natural hydrological processes which have been lost, due to urbanization and associated impermeable surfaces and the installation of pipe-based drainage [2]. Whilst the SuDS square emphasizes the equal importance of water quantity, water quality, amenity and biodiversity, regarding the likely benefits of integrating. When focusing on water quality, combinations of SuDS devices are often termed treatment trains, the focus of the present study is on water quantity reduction, and the term “SuDS management train” will be used

Methods

Results

Discussion

Conclusion