Spatial Evaluation of Multiple Benefits to Encourage Multi-Functional Design of Sustainable Drainage in Blue-Green Cities

Richard Fenner

doi:10.3390/w9120953

Abstract

Urban drainage systems that incorporate elements of green infrastructure (SuDS/GI) are central features in Blue-Green and Sponge Cities. Such approaches provide effective control of stormwater management whilst generating a range of other benefits. However these benefits often occur coincidentally and are not developed or maximised in the original design. Of all the benefits that may accrue, the relevant dominant benefits relating to specific locations and socio-environmental circumstances need to be established, so that flood management functions can be co-designed with these wider benefits to ensure both are achieved during system operation. The paper reviews a number of tools which can evaluate the multiple benefits of SuDS/GI interventions in a variety of ways and introduces new concepts of benefit intensity and benefit profile. Examples of how these concepts can be applied is provided in a case study of proposed SuDS/GI assets in the central area of Newcastle; UK. Ways in which SuDS/GI features can be actively extended to develop desired relevant dominant benefits are discussed; e.g., by (i) careful consideration of tree and vegetation planting to trap air pollution; (ii) extending linear SuDS systems such as swales to enhance urban connectivity of green space; and (iii) managing green roofs for the effective attenuation of noise or carbon sequestration. The paper concludes that more pro-active development of multiple benefits is possible through careful co-design to achieve the full extent of urban enhancement SuDS/GI schemes can offer.

Highlights

The purpose of this paper is to examine how the multiple benefits arising from urban drainage systems that incorporate elements of green infrastructure can be pro-actively considered during the design and selection process
Much useful analysis can be found in the literature on ecosystem services to help improve improve the the understanding understanding of help of multiple multiple benefits benefits which which emerge emerge from from aspects aspects of of urban urban greening
Ashley R. et al have made the following observation [5]: “If the added benefits to society that can be provided by using Sustainable Drainage Systems (SuDS)/GI are to be realised the ‘drainage’ perspective needs to be supplanted by one in which Blue-Green infrastructure is seen as a starting point for the planning of land use and property development or renovation; i.e., it is no longer ‘drainage’ that we need; rather what can be achieved is too valuable to be so pigeonholed”

Summary

Introduction

The purpose of this paper is to examine how the multiple benefits arising from urban drainage systems that incorporate elements of green infrastructure can be pro-actively considered during the design and selection process. This is important if flood mitigation benefits and the potential for wider positive impacts are to be simultaneously achieved. SuDS/GI solutions can contribute to ecosystem services and provide other benefits such as cost effective public health measures [1,2] It has been suggested the frequency of exposure to natural settings and the extent of vegetation cover may be important in improving human well-being, in the realm of mental health [3]. A recent UK briefing note identifies the following benefits for urban green infrastructure: urban temperature regulation, improving air quality, reducing surface water flooding, reducing pollution of urban water courses, noise reduction, Water 2017, 9, 953; doi:10.3390/w9120953 www.mdpi.com/journal/water

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