Customers see looking after our assets – pipes, pumps, works and equipment – as one of our core responsibilities. They want to know that we are investing to maintain them effectively so they provide a good service, now and in the future. A number of ODIs have been put in place to ensure strong service in this area. Four of these ODIs sit under the heading of Serviceability, the key measure of how we invest in assets to keep service at an acceptable level.
Infrastructure refers to underground assets such as pipes, while non-infrastructure refers to above ground assets like treatment works and reservoirs. These ODIs are made up from 13 measures, with our performance against each assessed as green, amber or red. For each measure, 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 limit for a second year in a row, and it moves to red. If one or more of the measures under an ODI is red, or two or more are amber, then we incur a penalty.
This year was one of the best for compliance for the quality of water discharged from our water recycling centres. We sample the quality of the recycled water at 723 sites and the results are used as a measure by the Environment Agency to assess our performance. In 2016, we recorded the lowest ever number of failing works – three, compared to six in 2015 and nine the year before. Overall the year ended with all water recycling measures comfortably within control limits, both for water recycling centres and for our sewerage network.
We also delivered good performance at our water treatment works and across our water networks. This included the number of works coliform failures, which fell from eight last year to just three, following improvements to our treated water tank inspections. However, the increase in burst mains caused by the dry autumn and cold winter saw us exceed the upper control limit for this measure and for the measure on interruptions to supply of longer than 12 hours. This means we will incur a penalty on our water infrastructure serviceability ODI.
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. The number of Category 3 incidents increased from a record low of 144 in 2015/16 to 217 – still well below the 390 we saw in 2014 and ahead of our target, which is to have no more than 298 Category 3 incidents by 2017/18. Performance is encouraging and we are focused on improving it further through predictive analytics, which allow us to use information on past pollutions to predict where we may have problems in the future, and proactive inspection and maintenance.
We are also investing to reduce incidents of flooding from our sewer network. Our performance in this area is measured against two separate ODIs, which look at the three-year average for incidents of internal and external flooding from our network. All incidents of sewer flooding count towards our performance, regardless of the cause. Two years into the AMP, we are beating our target for both internal and external flooding. The current three-year rolling average for internal flooding events is 430 against a target of 448 for the end of 2019/20, while the figure for external flooding stands at 5,464 against a target of 6,159 for the end of 2019/20. This is very encouraging, especially given the exceptionally high rainfall throughout late May and June 2016.
To deliver the outcomes our customers want demands the closest possible collaboration between us, our suppliers and our contractors. The majority of our £2 billion investment programme for 2015-2020 will be carried out by our delivery alliances, which will help provide our services until 2020. These differ from alliances elsewhere in the water industry, with an unparalleled degree of integration and alignment.
Our alliances have been tasked with finding further efficiency savings, and we are constantly working to become ever-more efficient, challenging ourselves and setting stretching goals. The emphasis is on the low carbon, low whole-life cost and on-time delivery of schemes while ensuring we meet quality standards. Between now and 2020 we will continue to invest heavily to increase the resilience of our services and protect customers' supplies in the face of growth and climate change. This includes work to:
Since the start of 2008, we have used steam boilers, rather than thermal dryers, to treat sludge at our water recycling centres. The boilers are more sustainable, effective and cheaper to run.
This year we began to roll out a Boiler Operative Accreditation Scheme (BOAS), which allows our boiler attendants to train to become boiler operators. Four have already qualified, meaning they can perform a much wider range of tasks on site. This removes the need for trained operators to travel from site to site, increasing the efficiency and safety of our operation. We aim to have a boiler operator at every site and on every shift by 2020.