Pollution
incidents

serviceability

internal flooding

External flooding

Percentage of sewerage capacity schemes using sustainable solutions

Investing for tomorrow

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ODI 1 of 5

Pollution incidents

This is the total number of pollution incidents classed as Category 3 by the Environment Agency that are due to escapes from our water recycling network. Incidents are ranked in order of severity, with Category 1 the most serious and Category 3 the least. Our performance on reducing pollutions caused by escapes from our water recycling network was very close to 2016 performance with 219 Category 3 incidents (an increase of just two), meaning we remain ahead of our ODI target to have no more than 298 incidents by the end of 2019/20. Extreme weather events in March and June 2016 led to a number of network and pumping station issues. These contributed to an increase in the number of pollutions caused by escapes from our water recycling network. Our ODI looks at the number of such pollutions classed as Category 3 by the Environment Agency. Incidents are ranked in order of severity, with Category 1 the most serious and Category 3 the least. This number compares to 390 such incidents in 2014. Performance is encouraging and we have a wide programme of activities to reduce pollution incidents and improve our understanding of their causes. This includes:

  • spending of around £6 million in the last financial year on planned preventative maintenance to reduce blockages and consequent pollutions
  • a priority, 'blue light' or fast response for areas with historical pollution risk and/or significant environmental sensitivity
  • investment in new technology for remote monitoring of discharges. This has been installed at key points on the network, both inland and coastal. More than 800 locations are now monitored around the clock
  • making a step change in pollution management through the use of 'predictive analytics', which allow us to use information on past pollutions to predict where we may have problems in the future
  • proactive inspections of high-risk assets
  • a 'pollution watch' campaign targeted at the public and river users to raise public awareness about the causes of sewage pollution, the impact it has and the signs to look out for
ODI 2 of 5

Serviceability

This is the key measure we use to monitor how we invest in our assets to keep their service at an acceptable level. It is split across 13 measures, grouped into four ODIs, covering below and above ground assets for water and water recycling.

Each measure is assessed as green, amber, or red. For each, we agree a normal or 'reference level', which is typically close to the best historical performance. There is also an 'upper control limit', which is the worst level of performance that can be accounted for by reasonable natural variation. If we perform worse than this upper control limit, the measure moves from green to amber. Perform worse than the control level for a second year in a row, and it moves to red.

Performance is also assessed as green, amber, or red for each of the four ODIs. If one or more of the measures under an ODI is red, or two or more are amber, then we incur a penalty.

Throughout the year, we have delivered good performance at our water treatment works and across our networks. This included just four works coliform failures, following improvements to our treated water tank inspections. Overall the year ended with all water recycling measures within control limits, both for water recycling centres (WRCs) and for our sewerage network.

ODI 3 of 5

Internal Flooding

This gives the number of properties flooded internally by water from our sewers, with our performance given as a three-year average. All incidents of sewer flooding count towards our performance, regardless of the cause.

Our focus is to spend money on measures such as non-return valves and flood doors, which reduce the risk of flooding to individual properties and which are more cost effective than large-scale engineering schemes.

Such schemes might cost millions of pounds to protect a handful of properties, making them an inefficient use of money and limiting the number of customers we could help. The focus on property-level protection allows us to reduce the risk of flooding to far more properties for a fraction of the cost. Investment has been targeted in areas where properties are vulnerable to flooding caused by storms, and by the failure of assets such as local sewage pumping stations.

Households are also being provided with information packs, explaining the problems that can be caused by sewer blockages and the steps people can take to reduce them and protect themselves from flooding.

We are still investing in large-scale engineering solutions where property-level protection is not possible. These schemes are being prioritised on the risk of flooding and on its possible consequences for our customers.

ODI 4 of 5

External Flooding

This gives the number of properties flooded externally by water from our sewers, with our performance given as a three-year average.

Our focus is to spend money on measures such as non-return valves and flood doors, which reduce the risk of flooding to individual properties and which are more cost effective than large-scale engineering schemes.

Such schemes might cost millions of pounds to protect a handful of properties, making them an inefficient use of money and limiting the number of customers we could help. The focus on property-level protection allows us to reduce the risk of flooding to far more properties for a fraction of the cost. Investment has been targeted in areas where properties are vulnerable to flooding caused by storms, and by the failure of assets such as local sewage pumping stations.

Households are also being provided with information packs, explaining the problems that can be caused by sewer blockages and the steps people can take to reduce them and protect themselves from flooding.

We are still investing in large-scale engineering solutions where property-level protection is not possible. These schemes are being prioritized on the risk of flooding and on its possible consequences for our customers.

ODI 5 of 5

Percentage of sewerage
capacity schemes using
sustainable solutions

Part of our challenge as a business and as a society is to find more sustainable, less carbon-intensive ways of working. Delivering sustainable drainage systems (SuDS) is one way in which we can start to put that into practice.

Instead of using traditional methods such as concrete storage tanks and bigger pipes to increase the capacity of our sewer system, the delivery of SuDS challenges us to look at alternatives. These include the use of rain gardens, water butts, or channelling excess water away from customers' properties.

We can also look at lower carbon engineering solutions like relining sewer pipes instead of replacing them. This cuts the amount of surface water infiltrating into the sewers and taking up space more properly used to carry sewage.

We have set ourselves a target for AMP6 to deliver 25 per cent of our sewerage capacity schemes using sustainable solutions like these. This will be a challenge as such an approach has never been tried before. We have delivered 22 schemes using sustainable solutions so far this AMP.

SuDS and so-called super SuDS that serve a number of developments allow a much more strategic approach to drainage. They can also help to unlock building and growth. Too often the building and adoption of SuDS is hampered because it is not clear who is responsible for their delivery, adoption and maintenance.

Action at a national level to clarify responsibilities around SuDS would encourage their use, as would removing the automatic right for developers to connect to the public sewer system. This – and the fact that water companies are not statutory consultees to the planning process – can mean houses are built without enough consideration for surface water flooding.