ESD Strategy

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Thames Waters Draft Water Resources Management
Plan 21 July 2008 NB This is very much a work
in progress and will be reviewed, updated and
amended prior to the Council considering the
dWRMP on 13 August 2008 Proposed reservoir
capacity 150 million Ml Proposed reservoir
yield 315 Ml/d 1 Ml 1 million litres
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• Thames Waters statutory duty to provide a secure
• supply of safe and clean water for its customers
• Appropriate measures to achieve secure water
  supply need to be supported, provided they are
  justified by clear evidence and sound analysis
• Actions to reduce demand for water
• Leakage 164 Ml/d saving in London by 2020,
  3,500 kms mains
• replacement, beyond economic level of leakage
• Metering compulsory metering 28 in 2010 to
  85 in 2030 tariffs
• From 2015/16
• Water efficiency measures approx 30 Ml/d
  saving
• audits, education, water butts, cistern
  displacement devices

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• Areas of Concern
• Departures from Government and
• Environment Agency guidance
• Questions about Thames Waters forecasts and
  assumptions
• Areas of ongoing research which could reduce
• supply demand deficit
• Appraisal of supply options not robust

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• Departures from Government and EA Guidance
• Per Capita Consumption (PCC)
• Governments aim to reduce PCC to 130 l/p/d by
  2030
• Water Strategy for England, Future Water, Feb
  2008 target of 130 l/p/d, possibly 120 l/p/d.
  SEEDAs target of 135 l/p/d by 2016
• However, Thames Water says this is very
  unlikely
• Thames Water forecasts a significant increase in
  PCC after 2020
• to 165 l/p/d by 2035
• Difference of 35 l/p/d with a total population
  of 9.723 million at 2030
• 340 Ml/d (Reservoir yield 315 Ml/d)
• Wholly unacceptable stance all of Thames
  Waters area identified as seriously water
  stressed

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• Sustainability Reductions
• (i.e. reduced groundwater abstraction licence
  volumes)
• Thames Water has included 2 time-limited
  sustainability reductions in
• its Target Headroom calculations Deptford and
  Bexley
• Contrary to EA guidance
• Has effect of increasing the forecast supply
  demand deficit but not
• clear by how much

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• Climate Change
• (principally impacting on supply reduced river
  flows,
• reduced groundwater, increased evaporation)
• Thames Water has used an alternative method for
  modelling
• climate change than recommended in EA guidance
• But EA says Thames Waters approach is
  reasonable and has
• a minimal impact on supply calculations

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• Outage
• (Temporary reduction in supply caused by
  mechanical failure
• or pollution events)
• Thames Water has used an alternative method for
  calculating
• outage than recommended in EA guidance
• But EA says Thames Waters approach is
  reasonable and has
• a minimal impact on supply calculations

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• Credibility of Thames Waters Assumptions
• Population Figures
• Population figures increased by 392,000
• clandestine and short-term migrant populations
  
• Equates to a demand of about 51 Ml/d
• Most likely population forecasts similar to
  ONS trend-based
• projections, but above policy-based projections
  by 3 by 2030
• Equates to a demand of about 38 Ml/d
• (Its unclear whether trend-based or policy-based
  population projections
• are most appropriate to use)

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• Demographic Projections
• Combination of higher most likely population
  figures
• and lower policy-based household figures
• Results in higher average household occupancy
  rates
• than trend-based projections (by about 0.05
  person in London, but extrapolated to total TWUL
  household of 4.14 million by 2030)
• Contradicted by Thames Waters own 2007 survey
  (which shows
• actual occupancy rates lower than TWs estimates
  but they use the estimates)
• Effect of increasing forecast unmeasured
  household demand
• (i.e. used as a factor in determining unmeasured
  household consumption)

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• PCC
• Thames Waters own recent evidence (2007) of
  reduced PCC
• (indoor components of appliances, toilet
  flushing, baths and showers outdoor components
  of garden watering, which is much lower than
  2003 data)
• However, continued use of data from 2003 (which
  shows higher
• levels of ownership and frequency of use of
  components of PCC)
• Assume PCC will increase year on year primarily
  driven by
• ownership of power showers and outdoor water use
  
• EA says Thames Waters forecasts for outdoor
  water use
• appear high
• Higher PCC has the effect of significantly
  increasing forecast
• demand 35 l/p/d 340 Ml/d 1 l/p/d 9.7 Ml/d

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• Compulsory Metering
• 10-year compulsory metering programme 2010
  2020
• Full coverage by 2020 (i.e. 80) and 84
  coverage by 2030
• However, full coverage is 93 in Thames
  Valley, 82 in London,
• and only 50 for flats in inner London (very low
  rate of penetration)
• Insufficient consideration given to internal
  meters/Automatic
• Meter Reading and assessed charges/bulk meter
  readings
• Counter to Governments statement that near
  universal metering
• is needed in seriously water stressed areas by
  2030
• 1 metering 2 Ml/d (very approximately)

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• Meters
• Thames Water assumes meters under-register
  actual water used by
• 3.24 (equates to only approx 2 Ml/d) for
  domestic properties and 4.89 for non-domestic
  properties
• However, meters can both under and over register
• Water Efficiency Measures
• Vague and unchallenging 30 Ml/d, but could
  do much better
• Need to target high consumption customers
  with awareness raising
• campaigns

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• Leakage
• Imperfect understanding of the location and
  amount of
• leakage will improve significantly as more
  customers are metered
• However, Thames Waters assumptions are based
  on
• current data no allowance made for expected
  reduction in uncertainty of reducing leakage
• Would equate to a demand saving

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• Target Headroom
• (Additional allowance made to account for
  uncertainty in the
• proposed measures to reduce demand and increase
  supply)
• Accounts for 206 Ml/d (7.4) of the total demand
  at 2030 (reservoir yield 315 Ml/d)
• Includes
• Variability in demographic projections but
  large amount of
• uncertainty has already been removed from
  calculations
• Increases in PCC but forecast PCC already well
  above
• Government targets, Thames Waters own evidence
  (2007) of reducing PCC, and outdoor components of
  PCC are less in London (and EA says TWs
  forecasts for outdoor water use are high)

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• Measured and unmeasured non-household
  consumption are
• increased by 11.67 and 25 respectively but no
  justification given for such high allowances
  (equates to approx 65 135 Ml/d)
• Availability of time-limited licences at
  Bexley and Deptford but
• EA guidance says such licences should not be
  included
• Gradual pollution of sources but outage also
  includes pollution
• events

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• Areas of New/Continuing Research
• Lower Thames Operating Agreement
• To be reviewed by 2015
• Review will determine how much water can be
  abstracted
• from the Lower Thames above Teddington Weir
• Will require proper scientific investigation
  and study
• However, well before the review, Thames Waters
• calculations assume a significant reduction in
  supply in
• London and SWOX (but not quantified)

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• Indirect Wastewater Reuse
• 5-year research programme at Deephams sewage
  treatment works
• Trial plant built to investigate possible use of
  state-of-the-art
• technologies
• However, as research is incomplete, a fully
  operational plant at
• Deephams is included only as a Contingency Option
  
• Option rejected of providing plants anywhere
  else in London or
• SWOX

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• Aquifer Storage and Recovery (ASR)
• No ASR schemes in use by Thames Water
• so potential yield uncertain
• Research continuing into feasibility and
  potential yield
• SWA SWOX Transfer
• Supply demand surplus in Slough/Wycombe/Aylesbury
  
• (SWA) Water Resource Zone throughout plan period
  
• Thames Water plans to examine the potential
  development
• of a SWA SWOX Transfer
• However, only included as a Contingency Option

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• Leakage Reduction Targets
• Subject to adequate funding (2009 Price Review),
  confidence
• in robustness of leakage reduction targets will
  increase above 50 (capital maintenance programme
  of mains replacement in London)
• This will decrease forecast demand

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• Metering and Tariffs
• Government review to encourage greater meter
  penetration in
• seriously water stressed areas
• Will encourage Thames Water to increase meter
  penetration
• for flats in inner London beyond 50
• Research ongoing into most effective tariffs
  seasonal or bulk
• (introduced from 2015/16)

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• Climate Change Projections
• New set of climate change projections
• Enable up-to-date assessments of operational
  risks
• from climate change
• Particularly significant as highest component
  of
• Target Headroom by far is uncertainty of the
  effects of
• climate change

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• Inadequacies of the Supply Options Appraisal
• Bulk Transfers
• dWRMP considers bulk transfer of water to other
  water companies
• (using existing supplies and potential use of
  proposed reservoir)
• However, Thames Water says No opportunities
  were
• forthcoming to introduce supplies into Thames
  Water
• (no explanation)
• Options of bulk transfers from other water
  companies in
• the South-East or from the River Severn via a new
  reservoir
• in the Lower Severn Valley (Longdon Marsh) not
  considered
• GARD highlights this as an option which has
  not been
• properly explored

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• Inter-Zonal Transfers
• SWA SWOX transfer potential yield of 10 Ml/d
  
• Included only as a Contingency Option

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• Indirect Wastewater Reuse
• Essex and Suffolk Water plant at Langford
• uses lamellar separation technology
• Southern Water is planning several wastewater
  reuse schemes
• to increase supply as alternatives to increasing
  reservoir capacity
• Thames Water is investigating possible use of
• state-of-the-art technologies such as reverse
  osmosis
• Considered as an option only on one site in
  London (Deephams)
• and not at all in SWOX
• Could yield up to 100 Ml/d at Deephams
• Similar yields could be achieved at sewage
  treatment works
• at Banbury, Oxford, Swindon, Beckton, Crossness
  and Windsor

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• Direct Wastewater Reuse
• Appears to be rejected as an option as it is
  considered
• publicly unacceptable on health concern grounds
  
• Smaller Reservoir
• Consideration of the above issues should result
  in a smaller
• supply demand deficit
• This would enable proper consideration of
  options
• for a smaller reservoir on a number of sites

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Thames Waters Forecasts In 1990, Thames Water
said the combined demand for London and SWOX
would be 2,767 Ml/d in 2016 Now, Thames Water
says the combined demand for London and SWOX
will be 2,442 Ml/d in 2020 and 2,653 Ml/d in
2035 The principal question, therefore, has to
be Why does Thames Water continue to claim the
need for a reservoir of the same size and in the
same location as proposed in 1990 when forecast
demand is now so much lower?
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Conclusion Taken together, these
matters lead to the conclusion that the forecast
deficit in the supply demand balance has been
overstated by Thames Water and, as a result, the
need for a 150mMl reservoir south of Abingdon in
this WRMP period has not been proven (A
compelling case for the reservoir needs to be
made before any decision is made to allow the
development given the massive scale of the
proposed reservoir, the dramatic impact it would
have on the surrounding landscape, the
significant disturbance to the local population
throughout its long construction period, and its
high cost)