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

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.

Managing urban flood resilience through the English planning system: insights from the ‘SuDS-face’

“…It has been alleged in the literature that little if any direct attention is given to the planning of the wider benefits to SuDS. For example, according to Fenner [33], any systematic procedure for pro-actively developing drainage infrastructure to deliver a specified range of predetermined desirable multiple benefits is rare and instead, if any multiple benefits emerge, this is at best sporadic, coincidental or at worst accidental. Interviewees report that multifunctional benefits are only purposively designed into 'big schemes', where there is availability of land.…”

Urban Stormwater Characterization, Control and Treatment

“…Other authors expanded the set of optimization functions considered, to include avoided flood damage costs (Cunha et al, 2017) as well as benefit intensity and benefit profile associated with a broader range of societal benefits, or ecosystem services, potentially provided by LID practices (Fenner, 2017). Di Matteo et al (2017b) presented one of the broadest optimization frameworks, which sought to identify optimal solutions across multiple stakeholders.…”

“…Implications to watershed-scale planning and assessment. Even amid evidence from field and monitoring studies that demonstrate the potential to improve watershed hydrologic function through LID and evidence of a high willingness to pay for associated environmental and amenity benefits among watershed inhabitants (Brent et al, 2017), widespread and watershed-scale implementation of LID lags (Dhakal and Chevalier, 2017;Fenner, 2017). Barriers to LID adoption may take the form of policy, governance, resource or cognitive barriers (Dhakal and Chevalier, 2017;Cousins, 2017;Kim and Li, 2017).…”

Achieving Urban Flood Resilience in an Uncertain Future

“…This is being done through the development of the next generation of hydrosystems models [2] that bridge the interfaces between urban/rural and engineering/natural hydrological systems. Flexible adaptation pathways are being assessed using a multiple benefits approach [3] to determine the most effective mix of blue-green and grey systems for any given location and time. Capturing the resource potential of stormwater through rainwater harvesting [4] and local energy recovery using micro-hydropower [5] is being examined as part of a multifunctional systems approach to urban flood management [6].…”