The potential to retrofit sustainable drainage systems to address combined sewer overflow discharges in the Thames Tideway catchment

Abstract

Experience of retrofitting SuDS in the UK is limited, and there are no well-established procedures for evaluating the feasibility, value, or cost-effectiveness of doing this, particularly at the catchment scale. This paper demonstrates a two-phase process for evaluating the potential to retrofit SuDS to address combined sewer discharges in three subcatchments within the Thames Tideway catchment of London. The first phase using hydraulic models, whilst the second phase considers how disconnection might practically be achieved. High levels of disconnection are technically possible, but practicably difficult. In selected cases, and with aggressive implementation of SuDS, CSO discharges could potentially be eliminated or reduced to acceptable levels without the need for any modifications to underground assets. However, retrofit SuDS could not eliminate the requirement for some form of sewer modification in any subcatchments.

Re-Thinking Urban Flood Management—Time for a Regime Shift

“…For economical as well as environmental reasons, an integrated approach is needed. New large-scale single-purpose construction projects, such as huge sewerage tunnels in old combined sewerage systems, have been strongly criticized, for example in Philadelphia [50,51], London [52] and Copenhagen. Integrated flood management calls for solutions with multiple purposes, which has a valuable function every day, not only once in 50 or 100 years.…”

Efficiency of stormwater control measures for combined sewer retrofitting under varying rain conditions: Quantifying the Three Points Approach (3PA)

“…For example, in some areas water conservation and reduction in potable water 374 use is a main concern and driver for SCMs (Campisano and Modica, 2015;Londra et 375 al., 2015). In other areas, the main concern may be limiting combined sewer overflows 376 (Petrucci et al, 2012;Stovin et al, 2013) or to conserve the pre-development catchment 377 water balance (Henrichs et al, 2016) and the river flow regime (Fletcher et al, 2013). 378…”

Evaluating the multiple benefits of a sustainable drainage scheme in Newcastle, UK

“…However, SuDS and BGI schemes tend not to be designed to maximise the provision of multiple benefits, but instead typically address one or two objectives, for example surface water management (Newell et al, 2013;Stovin et al, 2013). In many local authorities, SuDS and BGI frequently remain entrenched within water and flood management departments and, despite major investment and research into multi-functionality (e.g.…”