In order to deliver the required improvements to progressively reduce the adverse impact of storm overflows as detailed in the Environment Act, opportunities to treat overflows need to be further explored including their application, costs and benefits.  

Each year water companies spend millions of pounds on responding to and resolving problems caused by the disposal of inappropriate materials into the sewer network. It is estimated that 40-50% of all sewer blockages are caused by wet wipes with a further 15-20% been caused by FOG in some water companies. 

Together a more than half of all blockages are caused by the disposal of inappropriate materials making this one of the single biggest challenges in achieving zero uncontrolled discharges by 2050. 

To try and combat this issue each company has their own customer behaviour campaigns aimed at blockage reduction. These campaigns include a mixture of techniques from social media, radio & print adverts to more targeted interventions by network protection teams. Each campaign usually has a strap line associated with it. 

•    Keep it Clear” at Anglian Water.
•    “Stop the block” at Welsh Water.
•    “Think sink” at South West Water.
•    “Bin it don’t block it” at Thames Water and Yorkshire Water.
•    “Dwayne the Drain” at Northumbrian Water.
•    “Let life flow” at Wessex Water.

Despite the numerous campaigns by all the associated companies very little learning is shared at a national level. 

Develop a methodology to better represent how inlet restrictions are embodied within sewer modelling to improve our understanding of flood risk during severe rainfall events.

To tackle storm overflows and sewer flooding, the removal of surface water from the combined sewer system via SuDS represents a potentially more sustainable alternative to traditional grey infrastructure and has the potential to deliver wider benefits to the environment and society including longer term flood resilience. 

Initial costs and benefits appraisals (including carbon estimates) for SuDS through the Storm Overflow Evidence Project and Drainage and Wastewater Management Plans have indicated however that SuDS could be potentially higher in both cost and carbon. 

Because there are relatively few examples of the whole life costs and benefits of retro-fitted SuDS delivered by the Water Industry this research aims to further develop our understanding of the initial capital costs, long term opex costs,  and whole life benefits. 
It will also deliver tools that can be used for planning purposes and to influence regulation and policy. 

There are several methods recognised to detect infiltration (CCTV, Electroscan etc) but all appear to have shortcomings that prevent them being as effective as is needed. Infiltration seems to be an intractable problem for several companies in the south of England (and others to a lesser extent) and can only be remedied where measurable (short of wholesale replacement/relining).

This suggestion is to engage with universities/academia to suggest and pilot alternative technologies