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Water sector adaptation under the Climate Change Act 2008

Organisation: United Utilities Water PLC

Case study focus

Risk assessment/Risk management

United Utilities Water PLC (UUW) holds licences to provide water and wastewater services to a population of approximately seven million people in the North West of England. They serve domestic and business customers from Cumbria in the north to Cheshire in the south, taking in the sub-regions of Lancashire, Merseyside and Greater Manchester.

This case study summarises a report submitted by UUW to the Secretary of State for Environment, Food and Rural Affairs, in accordance with the requirements of the Climate Change Act 2008. The report brings together the work UUW has done, and plans to do, to adapt to climate change. The adaptation plan is targeted specifically up to 2035, a timeframe that was relevant to the company's 25 year business planning timescales at the time of the assessment.

What was it used for?

Data from UKCP09 scenarios were used in a climate change risk assessment exercise involving a number of experts from within the business. Workshops were held for each area of the business. Future climate change projections were presented and facilitated discussions held to consider the potential effects of climate change on business assets and operations. The likelihood and consequence of potential impacts were considered to produce scores for each risk. Adaptation activities that were already in place were identified, and the risk score reassessed where appropriate.

Which UKCP09 products were used?

The Observed Trends Report

Key findings (for the North West of England)

Approach and how UKCP09 was used

In preparation for the workshops UUW reviewed the available UKCP09 data and adopted the following protocol:

  • The high emissions scenario data was used - UUW concluded that evidence at the time of reporting showed that emissions were already at the high level, if not above, and the failure to reach an international agreement in Copenhagen and Cancun 2010 meant there was no statutory mechanism in place to cut emissions on a global scale.
  • The 50% probability level data were used as the central estimate was considered to represent an acceptable level of uncertainty for UUW's purposes.1

UUW presented the projections to a panel of company experts. The following data were used in the workshops to firstly help frame the issue of a changing climate, and then to assess the risks to UUW:

  • Graphs and maps from the Observed Trends Report were used in a presentation showing observed regional or local changes. Data most relevant to UUW's operating area (North West of England) was clearly highlighted and a summary of observed changes was presented to participants:

o trends in mean annual, summer and winter temperature from 1914 - 2006;

o trends in summer and winter precipitation from 1914 - 2006;

o trends in total precipitation from 1961 - 2006;

o Liverpool annual mean sea level from ~1860 - 2000.

  • Key findings for projections for the North West of England were also shown:

o changes in mean winter and summer temperature 2020s, 2050s and 2080s;

o changes in summer daily maximum temperature 2020s, 2050s and 2080s;

o changes in annual, winter and summer precipitation 2020s, 2050s and 2080s

o relative sea level 2020s, 2050s and 2080s.

Projections were fitted to UUW's business timeframe of 2035 by inferring the figures from the key findings which are provided for the 2020s, 2050s and 2080s time periods. The inferred projections data were used by experts to assess the initial level of risk at 2035, identifying any adaptation actions already being undertaken, and reassessing the risk with this in mind.

Difficulties & limitations

UUW required key findings that fitted the business timeframe of 2035. Since the UKCP09 findings do not present data for any one year, UUW looked across data spanning 2020s to 2080s (50% probability level, High emissions scenario) to make an assessment of what changes they could expect within their business planning timeframe.2

At the risk assessment workshops, an attempt was also made to repeat the detailed risk assessment for the 2050 and 2080 time horizons. However, UUW concluded that due to uncertainties associated with the projections that far into the future, the detail of the risk would be irrelevant at the time of the assessment. However, UUW acknowledged that there could be significant changes to the climate and therefore a need to shift business activities accordingly.

Lessons learned

UUW's risk assessment workshops enabled the company to identify priority impacts and adaptation activities for each of their Water, Wastewater and Support Services. These included:

  • Carrying out a flood protection programme (2010-2015).
  • Reviewing emergency electricity supply arrangements for all key assets.
  • Joint working with the Environment Agency and Local Authorities on surface water management issues.
  • Reviewing climate change impact on water resources using UKCP09 and rainfall-runoff modelling.
  • Producing an odour management plan for all sites using a risk based approach and identify sites where there is a case for investment.
  • Working with suppliers to help them adapt to the impacts of climate change.
  • Continue to monitor and implement health and safety policies related to hot weather risks.

The workshops also enabled potential opportunities and benefits associated with climate change to be identified. These included:

  • Increased rainfall leading to increased flows in rivers and greater dilution for effluent discharge leading to reduction in risk of non compliance with existing consent and potential for seasonal consents with relaxed standards during the winter.
  • Drought conditions and increased evaporation leading to a high soil moisture deficit and sludge becoming a more desirable agricultural product because of its high water content.
  • Warmer temperatures enabling increased microbial activity and increased biogas production.

Although it was considered at the time of the assessment to be too early in the process to be able to quantify the potential benefits or the time at which they could be realised, UUW felt that the impacts and opportunities identified would have a positive impact on, and benefit to, the business.

How will the result be communicated?

The results of UUW's climate change risk assessment are presented in their report of Jan 2011 to the Secretary of State for Environment, Food and Rural Affairs, submitted in accordance with the requirements of the Climate Change Act 2008.

Find out more


1 Alternatively multiple probability levels can be used in order to capture the range of uncertainty that is present in the projections.

2 For more detailed risk assessments and for decision making at the local level, the User Interface can be used to analyse the full range of probability levels. 30-year time slices are presented every 10 years from 2020s to the 2090s.