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Wessex Water’s Grid - overview
• Wessex Water’s largest ever construction project• Valued at over £220M• Commenced in 2010, due to complete in 2017• Long term strategic vision to address existing and
potential water supply and customer issues:• Security of supply and resilience• Reduction in abstraction licence• Supply demand balance• Quality issues• Presentation not focussed on modelling but Project
contains all the elements used in modelling
3
Presentation structure
• Development of the concept– Strategic objectives– What do customers want?– Why do we need a grid?– Is it the best solution?– How catchment management fits in
• Design & construction– Team structure– Project objectives & Scope of works– Environmental constraints– Concept development– Programme
4
Strategic objectives
• To address customer priorities• To align investments with our strategic direction statement• To resolve three key issues:
– Meeting demand for water over next 25 years– Improving security of supply– Maintaining drinking water quality
5
What do customers want?
Willingness to pay for improvements
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Leakagereduction
Security ofsupply
Reducing
greenhousegas em
issions
Drinking w
aterquality
Taking water
from rivers
Internal flooding
River w
aterquality
Beaches &
bathing waters
External
flooding
Pollution
incidents torivers
£ pa
for 1
0% c
hang
e
Indicative cost benefit ratios
0
0.5
1
1.5
2
Leakagereduction
Security ofsupply
Reducing
greenhousegas em
issions
Drinking w
aterquality
Taking water
from rivers
Internalflooding
River w
aterquality
Beaches &
bathing waters
External
flooding
Pollution
incidents torivers
• Our research shows that customers want us to ‘get the basics right’ and deliver our services in a sustainable way
• Improvements in security of supply and drinking water quality ranked very highly in the detailed willingness to pay surveys
6
Wessex Water supply area
7
• Why do we need a grid?– Standalone sources (21%)– 23.5 Ml/d of low flow reduction (4%)– 43 Ml/d of high nitrate sources (8%)– Growing peak demand
8
This couldn’t happen to us?
9
Stand alone sources
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
Existing network
Stand alone sources
LEGEND
10
Low flows reductions
R. Wylye
R. Avon
-5 Ml/d -6 Ml/d -1.5 Ml/d
-11 Ml/d
-23.5 Ml/d
Low Flow licence reductions
Brixton Deverill Codford
Newton Toney
Clarendon
R. Wylye
R. Avon
-5 Ml/d -6 Ml/d -1.5 Ml/d
-11 Ml/d
-23.5 Ml/d
Low Flow licence reductions
-5 Ml/d -6 Ml/d -1.5 Ml/d
-11 Ml/d
-23.5 Ml/d
Low Flow licence reductions
Brixton Deverill Codford
Newton Toney
Clarendon
11
Deteriorating raw water - nitrates
Fonthill Bishop Nitrate Trend
0
2
4
6
8
10
12
14
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
Nitr
ate
as m
g/l a
s N
12
At risk nitrate sources
Existing network
Sources at risk of exceeding nitrate limits
LEGEND
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
13
Increasing demand
300
350
400
450
500
550
600
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035
Dis
trib
utio
n in
put (
Ml/d
)
Normal year demand forecast Dry year demand forecastPeak week demand forecast Weekly historic demandAnnual average demand Available resources
14
Presentation structure
• Development of the concept– Strategic objectives– What do customers want?– Why do we need a grid?– Is it the best solution?– How catchment management fits in
• Design & construction– Team structure– Project objectives & Scope of works– Environmental constraints– Concept development– Programme
15
Strategic options
Issue Plan A Holistic solution
Plan BIndividual solutions
Meeting demand and low flows
Grid New water resource developments
Drinking water quality
Grid & catchment management
Additional water treatment plants
Security of supply Grid Local network improvements
16
Costs and benefits
Plan A Holistic solution
Plan BIndividual solutions
Net benefits (present value) £m
162 - 52
Cost beneficial? Yes NoOperating cost £m pa 2.0 3.1
Operational carbon emissions C02e thousand tonnes pa
4.4 6.1
Security of supply – number of consumers no longer at risk of supply restrictions
150,000 35,000
17
How the grid addresses the key issuesLocal links omitted for clarity
Existing networkProposed pipelinesSources at risk of exceeding nitrate limitsStand alone sourcesLow flow sourceArea of supply demand deficit
LEGEND
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
18
How the grid addresses the key issuesLocal links shown
Existing networkProposed pipelinesSources at risk of exceeding nitrate limitsStand alone sourcesLow flow sourceArea of supply demand deficit
LEGEND
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
.MAIN
19
The projects will deliver multiple outputs
• Ofwat– Final determination
• Environment Agency – National Environment plan
• Drinking Water Inspectorate – Undertakings
20
Key dates - 8 year programme with interim milestones
Activity Date
Project Launch 1 April 2010Blashford WTW DWI undertaking March 2014Nitrate schemes DWI undertakings March 2015Elimination of stand alone sources March 2015Completion of integrated grid allowing low flows licences to be revoked
March 2018Commissioning in 2017
21
How catchment management fits in
Fonthill Bishop Nitrate Trend
0
2
4
6
8
10
12
14
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
Nitr
ate
as m
g/l a
s N
22
Catchment management activity
• Reduce risk whilst grid is implemented• Ensure long term supply of compliant
water & optimise operating costs• Advocacy• Nitrates
– Continue 4 AMP4 sites– 8 further sites that may fail in AMP5
• Pesticides– Friar Waddon
• Farmer has agreed to move pesticide activity to another site
23
Presentation structure
• Development of the concept– Strategic objectives– What do customers want?– Why do we need a grid?– Is it the best solution?– How catchment management fits in
• Design & construction– Team structure– Project objectives & Scope of works– Environmental constraints– Concept development– Programme
2424
Project Team Structure
Wessex Water Services Ltd
Wessex Engineering and Construction Services
Atkins Ltd
Designer
Trant ConstructionCivil & MEICA
Contractor
May GurneyCivil & MEICA
Contractor
Work stream
25
Programme Manager& CDMc
TRANT MAY GURNEY ATKINSProject
ManagementTeam
CommercialManagerPlannerDesign
Co-ordinators
GroupCommercial Manager
QuantitySurveyors Design PMs
Environmental ServicesEstates
ICAEstimating
Operations Support Team
Network Experts
Grid Workstream
26
Project objectives
• Improve security of supply
• Provision for reduction in abstraction licences
• Provision for deteriorating raw water quality
• Meet future water supply demand
27
Concept Development
• Original concept – called GC1• Revised concept – GC2• Updated GC2 November 2012
28
Grid Concept 1Local links shown
Blandford
Shaftesbury
Existing networkProposed pipelinesSources at risk of exceeding nitrate limitsStand alone sourcesLow flow source
LEGEND
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
.MAIN
Grid Concept 1
Grid Concept 1As PR09 business plan, new link north from Blashford with alternative route around Salisbury
29
Grid Concept 2Local links shown
Blandford
Existing networkProposed pipelinesSources at risk of exceeding nitrate limitsStand alone sourcesLow flow source
LEGEND
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
.MAIN
Grid Concept 2
Grid Concept 2Synergies with other schemes along Stour valley & new link north to Whitesheets SR
Shaftesbury
30
B R
E L
Bristol
BathChippenham
Salisbury
Bournemouth
Poole
Dorchester
Taunton
Bridgwater
Yeovil
.SPINE
Grid Concept 2Local links shown + updated routes
Existing networkProposed pipelineSource at risk of exceeding nitrate limitsStand alone sourceLow flow source
LEGEND BlandfordForum
Shaftesbury
31
Programme of works
• More than 25 individual projects
• Value ranging from £ 0.5 – 30M
• 150km of new Pipelines
• 30 new / uprated Pumping Stations
• 11 new Service Reservoirs
32
Corfe Mullen to Salisbury transfer scheme – 65km
32
33
Environmental constraints
7 AONBs2 National Parks539 Sites of special scientific interest6819 County Wildlife sites4500 Scheduled Monuments41748 Listed Buildings36000+ Records of Protected Species3 World Heritage Sites1 Heritage Coastline
34
Environmental Factors
34
35
Environmental Factors
35
36
Typical Pipeline Easement
36
37
Considerate Construction and waste management
• Spoil to be re-used where possible as trench backfill material
• Use excess trench spoil at other sites for service reservoir landscaping etc
• Trenchless technology to be used to cross ;– Rivers and watercourses– Railways– Trunk roads and A roads
38
Considerate Construction
• Traffic management plans to reduce impact of construction traffic on the local road systems
• Minimise construction traffic on roads by using pipeline easements instead
• Minimise volume of construction traffic by avoiding double handling, location of compounds etc
• Minimise construction durations through effective planning
39
New Infrastructure
40
Booster Pumping Stations
40
41
Considerate Construction
41
42
Considerate Construction
42
43
Aerial photo’s (from Wessex Drone)
44
45
46
47
48
Ground photo’s
49
50
51
Delivery Programme
AMP 5 AMP 6
2010 2011 2012 2013 2014 2015 2016 2017
Options
Outline design
Detailed design
Construction
52
Water supply grid website(www.wessexwater.co.uk/grid)
Conclusion
– Wessex Water’s largest and most complex project
– The only Water Industry project spanning two AMPs
– Aligns with 25 year vision
– Delivers customer priorities
53