Decision-Making and Sustainable Drainage: Design and Scale

Susanne Charlesworth,Craig Lashford,Frank Warwick

doi:10.3390/su8080782

Abstract

Sustainable Drainage (SuDS) improves water quality, reduces runoff water quantity, increases amenity and biodiversity benefits, and can also mitigate and adapt to climate change. However, an optimal solution has to be designed to be fit for purpose. Most research concentrates on individual devices, but the focus of this paper is on a full management train, showing the scale-related decision-making process in its design with reference to the city of Coventry, a local government authority in central England. It illustrates this with a large scale site-specific model which identifies the SuDS devices suitable for the area and also at the smaller scale, in order to achieve greenfield runoff rates. A method to create a series of maps using geographical information is shown, to indicate feasible locations for SuDS devices across the local government authority area. Applying the larger scale maps, a management train was designed for a smaller-scale regeneration site using MicroDrainage® software to control runoff at greenfield rates. The generated maps were constructed to provide initial guidance to local government on suitable SuDS at individual sites in a planning area. At all scales, the decision about which device to select was complex and influenced by a range of factors, with slightly different problems encountered. There was overall agreement between large and small scale models.

Highlights

Sustainable Drainage (SuDS) is a multiple-benefit and flexible means of addressing many of the environmental impacts associated with urbanization and industrialization
The multiple benefits of the SuDS approach are exemplified by the SuDS “triangle” [1] of water quantity reduction as already discussed, but at the same time water quality is improved, and amenity and biodiversity are provided [2]; most recently this has been represented by the SuDS “square” [3]
Research to date has typically focussed on the role of individual SuDS devices such as a green roof, or an area of porous paving [9,10], with little attention paid to the effects of combining devices into an overall management train

Summary

Introduction

Sustainable Drainage (SuDS) is a multiple-benefit and flexible means of addressing many of the environmental impacts associated with urbanization and industrialization. It does this by mimicking nature, infiltrating where ground conditions allow, detaining excess stormwater and conveying it slowly to the receiving watercourse. There are other benefits such as [4]’s “SuDS Rocket” whereby a suitable single SuDS device, or preferably an efficiently designed full SuDS management train, can mitigate and adapt to climate change One example of this is the ability of any Green Infrastructure (GI) associated with SuDS such as green roofs or swales to sequester and store carbon (see [5]). This paper demonstrates a novel support system for SuDS selection, based on the design of a full management train capable of mitigating large scale flood events, and compares its performance against conventional pipe based systems

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