Southern Water
Climate change
Corporate Strategy
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CLIMATE CHANGE AND WASTEWATER
IMPACT OF GLOBAL WARMING
The generally accepted view of climate change impacts is as follows:
 Dryer summers, but with fewer, heavier storms
 Generally wetter winters
 Higher sea level
 Lower summer river flows
 Higher winter river flows
 Higher temperatures
LIKELY IMPACT ON WASTEWATER
Dryer summers, but with fewer, heavier storms
 Increased flooding from sewers arising from heavier rainfall
 Increased spills from overflows, impacting on river quality, bathing beaches and shellfish
waters
 Increased risk of blockage arising from longer periods of low flow
 Impact on treatment works arising from longer periods of low flow
Generally wetter winters
 More frequent winter flooding
 Increased infiltration into sewers, with higher groundwater table
 Impact on treatment works through greater volumes of stormwater
Higher sea level
 Increased need for pumping to deal with surface water drainage
 Possible flooding of wastewater assets
Lower summer river flows
 Higher effluent quality required from wastewater treatment plants to maintain river quality
Higher winter river flows
 Potential flooding of wastewater assets
Higher temperatures
 Potential for additional odour problems
NATIONAL ACTIVITY
WaterUK is the industry body representing the water and wastewater companies. A number of focus
groups and working groups have been set up to consider and share information and best practice. The
key groups are as follows.
Climate Change Focus Group
This is the co-ordinating group and covers:
 Clean and dirty water
 Response to Climate Change Bill
 Development of industry strategy for both mitigation and adaptation
 Implications for the next Periodic Review (covering Water Co investment in the
period 2010-2015)
 Co-ordination of work at UK and EU level
 Influencing policies at national and local level
Carbon Accounting Working Group
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Southern Water
Climate change
Corporate Strategy
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Accounting for carbon outputs is a complex area, which is not fully understood, and with no
agreed methodology. This group is tasked with making recommendations on: how carbon
outputs should be calculated (including the impact of other greenhouse gases such as methane
and nitrous oxide); operational and embedded carbon; company carbon footprint, customer
footprint, and the boundary between the two.
Energy Management Forum
This group considers best practice for energy management within the industry.
UKWIR (UK Water Industry Research) is the body responsible for co-ordinating research on behalf of
the Water and Wastewater companies. There is a significant amount of research being undertaken or
proposed in connection with climate change, in particular:
 Strategic framework to bring together climate change related research
 Design rainfall for sewerage networks
 Carbon accounting
 Customer carbon footprint
 Impact on environmental standards
 Support for Defra’s Integrated Urban Drainage Pilot Studies
SOUTHERN WATER ACTIVITY
Southern Water is currently preparing its Business Plan for the next Price Review Period (covering the
period 2010-2015). A key element of the plan will be a consideration of climate change, its impact, and
the consequences for water and wastewater services, and the need for adaptation and mitigation
measures.
On mitigation the company is giving consideration to the potential for a reduction in carbon output,
through for example:
 Energy saving
 Use of green/renewable energy sources
For new investment, we are reviewing how to account for operational carbon output and embedded
carbon (i.e. the carbon output for the construction work). This will be used as one of a number of
measures in the choice of scheme options.
On adaptation we are using revised rainfall statistics based on Defra recommendations (whilst awaiting
the results of research referred to above). We will also be reviewing the resilience of key infrastructure
given the increased likelihood of severe flooding as a result of increased rainfall, and sea level rise.
B N Luck
Sewerage Strategy Manager
September 2007
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