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Taking account of climate change in long term
water resources plans
Oxford University Climate and Water Seminars
Steven Wade
Group Manager (Water), HR Wallingford
Steven Wade
Group Manager (Water), HR Wallingford
Page 2
Overview
•Background – water resources in the South
East of England
•Applied research to support guidelines
• Scientific approach (dealing with uncertainties etc)
• Stakeholder participation
• Practical tools and guidance
•How are climate data incorporated in plans?
• Company final plans?
• What next?
Page 3
Introduction: Water Availability & Supply in
England and Wales
20%80%Southern
Region
75%25%Thames
Water
50%50%Anglian
Water
Surface
Water
Ground
water
Public
Water
Supply
Water Availability (Groundwater):
(Environment Agency, 2001).
Page 4
Introduction: Water Availability & Supply in
England and Wales (Surface Water)
Summer Winter
(Environment Agency, 2001).
Page 5
Water resources planning
Anglian Water
HOT SPOT: LINCOLN • Transfer water from Elsham • Investigate Future Trent Source
HOT SPOT: GRANTHAM • Membrane plant at Saltersford • Long Term: Complete the Central Links Trunk Main (postAMP5) HOT SPOT: LINCS/CAMBS FENLAND
• Transfer water from Wing • Wing WTW Extensions
HOT SPOT: MID/NORTH NORFOLK • Part of Strategic Main • Stoke Ferry WTW - AMP5
HOT SPOT: IXWORTH / BURY ST. EDMUNDS • Increase supply from Ixworth • Future Supply from Thetford
HOT SPOT: IPSWICH / COLCHESTER • Link Main Ipswich - Colchester • Link Main Colchester - Halstead • Increase take from Ardleigh • Increase blend from Lexden • AMP5 - Extend Alton WTW
HOT SPOT: RUTHAMFORD (WEST) • Wing WTW Extensions • Duplication of existing trunk mains
WATER SUPPLY/DEMAND BALANCEStrategic Schemes
Existing Infrastructure
Proposed AMP4Infrastructure
BOURNE
IPSWICH
MURSLEY
NORWICH
BUCKINGHAM
SHERINGHAM
BRAINTREE
TOWCESTER
MILTON KEYNES
BARNOLBY
GRANTHAM
DAVENTRY
BURY ST EDMUNDS
COLCHESTER
Proposed AMP4 SourceWorks
AW SDB Team 12-03
MARCH
WISBECH
Future Infrastructure
Post AMP4 Source Works
REZONE
TRANSFER
REZONE
STOKEFERRY
TRANSFER
TRANSFER
LINK
WINGEXTNS
WINGINFRASTRUCTURE
CAISTOR
TRANSFER
IXWORTH
TRANSFER
ALTONWATER
TRANSFER
THREE VALLEYS WATER Co. • Take full allocation (91Ml/d Ave)
Grafham
LINCOLN
LINK
BradenhamRes
Page 6
Water Resource Planning in the UK
•Water Resource Plans• Supply Demand
Balance (25 + years)
• Options Appraisal
• Economic Assessment
• Determine funding for and timing of new schemes
•Drought Plans • Set out drought triggers
and management for 10yr RP+ droughts
Page 7
Overview of research for water industry &
Environment Agency
• Background • Climate change considered since 1990 and in WRPs since
1997 – latest emphasis on risk and uncertainty
• UKWIR/EA Project aims (ToR) • To produce a robust methodology which water
companies can use for the assessment of the impact of climate change in water resource planning and which has the support of the Regulator
• To build on the procedure for the rapid determination of the effects of climate change by the 2020s on mean monthly run-off and average annual groundwater
recharge, developed for UKWIR (03/CL/04/2)
Page 8
Climate change scenarios – from GCM to catchment scale
• Stage 1
• Application Regional Climate
Model HadRM3
• Interpolation of UKCIP02 data
to catchment scale
• Stage 2
• Develop a procedure to
downscale multiple Global
Climate Models
• Catchment scale scenarios
based on multiple models
Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high
emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.
(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)
Summer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitation
percentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change with
respect to the respect to the respect to the respect to the respect to the respect to the respect to the respect to the respect to the
1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)
Crown Copyright 2002. The UKCIP02 Climate Scenario data have been madeavailable by the Department for Environment, Food and Rural Affairs (DEFRA).DEFRA accepts no responsibility for any inaccuracies or omissions in the data
nor for any loss or damage directly or indirectly caused to any person or bodyby reason of, or arising out of any use of, this data.
�
Percentage changePercentage changePercentage changePercentage changePercentage changePercentage changePercentage changePercentage changePercentage change(%)(%)(%)(%)(%)(%)(%)(%)(%)
30 to 3525 to 3020 to 2515 to 2010 to 150 to 10
-10 to 0-20 to -10-30 to -20-40 to -30-50 to -40-60 to -50
Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high Medium-high
emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.emissions scenario.
(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)(2020s)
Summer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitationSummer precipitation
percentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change withpercentage change with
respect to the respect to the respect to the respect to the respect to the respect to the respect to the respect to the respect to the
1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)1961 - 90 climate)
Crown Copyright 2002. The UKCIP02 Climate Scenario data have been madeavailable by the Department for Environment, Food and Rural Affairs (DEFRA).DEFRA accepts no responsibility for any inaccuracies or omissions in the data
nor for any loss or damage directly or indirectly caused to any person or bodyby reason of, or arising out of any use of, this data.
Percentage changePercentage changePercentage changePercentage changePercentage changePercentage changePercentage changePercentage changePercentage change(%)(%)(%)(%)(%)(%)(%)(%)(%)
30 to 3525 to 3020 to 2515 to 2010 to 15
0 to 10-10 to 0-20 to -10-30 to -20-40 to -30-50 to -40-60 to -50
Page 9
Downscaling procedure: Example (Vidal and Wade,
2007)
Page 10
Average changes in temperature (2020s)
A2 scenario
Page 11
Changes in rainfall, 2020s
A2 scenario (UKWIR, 2007)
Jan Feb Mar Apr
May Jun Jul Aug
Sep Oct Nov Dec
-14 %
-12 %
-10 %
-8 %
-6 %
-4 %
-2 %
0
+ 2 %
+ 4 %
+ 6 %
+ 8 %
+ 10 %
+ 12 %
+ 14 %
+ 16 %
+ 18 %
+ 20 %
+ 22 %
UKWIR, 2007
-50
-40
-30
-20
-10
0
10
20
30
40
50
Jan
Feb Mar Apr
May Ju
n
Jul
Aug
Sep Oct
Nov
Dec
Win
ter
Spr
ing
Summ
erA
utum
n
Pe
rce
nt ch
an
ge
-40
-30
-20
-10
0
10
20
30
40
Jan
Feb Mar Apr
May Ju
n
Jul
Aug
Sep Oct
Nov
Dec
Win
ter
Spr
ing
Summ
erA
utum
n
Pe
rce
nt ch
an
ge
Mersey, NW England
Stour, SE England
Page 12
Modelling process for 2006 and ongoing work
UKCIP08 climate change factors
(25 km- no downscaling)
2 rainfall-runoff models (multiple
calibrated versions – observed rainfall and PET 1961-90)
-50 0 +50
Jan
-50 0 +50
Feb
-50 0 +50
Mar
-50 0 +50
Apr
-50 0 +50
May
-50 0 +50
Jun
-50 0 +50
Jul
-50 0 +50
Aug
-50 0 +50
Sep
-50 0 +50
Oct
-50 0 +50
Nov
-50 0 +50
Dec
Distribution of monthly flow factors
weighted by climate scenario, percentiles and rainfall-runoff model fit (2020s and 2030s)
Medium emission A1B:
Factored rain 10th percentile
and PET Median (Oudin)
(Weight from Pdf)
Catchmod Ensembles
PDM Ensembles
Medium emission A1B:
Factored rain 90th percentile
and PET Median (Oudin)
(Weight from Pdf)
Catchmod Ensembles
PDM Ensembles
Low emission B1:
Factored rain 50th percentile
and PET Median (Oudin)
(Weight: 0.33)
Catchmod Ensembles
PDM Ensembles
Change in flow (2020s)
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
Jan
Feb
Mar
Apr
May Ju
n
Jul
Aug Sep Oct
Nov
Dec
Q95
Perc
ent
cha
nge
5 25 50
75 95 Simplified MEDIAN SCENARIO
User selected DRY SCENARIO User selected WET SCENARIO
Note: Model runs left out if poor fit
Change in flow 2030s
High emission A1F1:
Factored rain 50th percentile
and PET Median (Oudin)
(Weight: 0.33)
Catchmod Ensembles
PDM Ensembles
Medium emission A1B:
Factored rain 50th percentile
and PET Median (Oudin)
(Weight from Pdf)
Catchmod Ensembles
PDM Ensembles
UKCIP08 climate change factors
(25 km- no downscaling)
2 rainfall-runoff models (multiple
calibrated versions – observed rainfall and PET 1961-90)
-50 0 +50
Jan
-50 0 +50
Feb
-50 0 +50
Mar
-50 0 +50
Apr
-50 0 +50
May
-50 0 +50
Jun
-50 0 +50
Jul
-50 0 +50
Aug
-50 0 +50
Sep
-50 0 +50
Oct
-50 0 +50
Nov
-50 0 +50
Dec
Distribution of monthly flow factors
weighted by climate scenario, percentiles and rainfall-runoff model fit (2020s and 2030s)
Medium emission A1B:
Factored rain 10th percentile
and PET Median (Oudin)
(Weight from Pdf)
Catchmod Ensembles
PDM Ensembles
Catchmod EnsemblesCatchmod Ensembles
PDM EnsemblesPDM Ensembles
Medium emission A1B:
Factored rain 90th percentile
and PET Median (Oudin)
(Weight from Pdf)
Catchmod Ensembles
PDM Ensembles
Catchmod EnsemblesCatchmod Ensembles
PDM EnsemblesPDM Ensembles
Low emission B1:
Factored rain 50th percentile
and PET Median (Oudin)
(Weight: 0.33)
Catchmod Ensembles
PDM Ensembles
Catchmod EnsemblesCatchmod Ensembles
PDM EnsemblesPDM Ensembles
Change in flow (2020s)
-50
-40
-30
-20
-10
0
10
20
30
40
50
60
Jan
Feb
Mar
Apr
May Ju
n
Jul
Aug Sep Oct
Nov
Dec
Q95
Perc
ent
cha
nge
5 25 50
75 95 Simplified MEDIAN SCENARIO
User selected DRY SCENARIO User selected WET SCENARIO
Note: Model runs left out if poor fit
Change in flow 2030s
High emission A1F1:
Factored rain 50th percentile
and PET Median (Oudin)
(Weight: 0.33)
Catchmod Ensembles
PDM Ensembles
Catchmod EnsemblesCatchmod Ensembles
PDM EnsemblesPDM Ensembles
Medium emission A1B:
Factored rain 50th percentile
and PET Median (Oudin)
(Weight from Pdf)
Catchmod Ensembles
PDM Ensembles
Catchmod EnsemblesCatchmod Ensembles
PDM EnsemblesPDM Ensembles
Clim
ate scen
arios based
on
TA
R G
CM
s, FAR
GCMs, Ensem
bles, H
adRCM�
UKCP09
Page 13
Prospects for river flows – role of storage Multi-model, A2 scenario, 2020s (UKWIR, 2007)
J F M A M J J A S O N D-50
-40
-30
-20
-10
0
10
20
30
40
50
Ch
an
ge
in
mo
nth
ly f
low
s (
%)
Itchen@AllbrookHighbridge (42010)
90% confidence intervals
50% confidence intervals
median
J F M A M J J A S O N D-50
-40
-30
-20
-10
0
10
20
30
40
50
Ch
an
ge
in
mo
nth
ly f
low
s (
%)
Tamar@Gunnislake (47001)
90% confidence intervals
50% confidence intervals
median
BFI=46%
BFI=96%
Page 14
Average changes in monthly flow for 70 catchmentsMulti-model, A2 scenario, 2020s (UKWIR, 2007)
Page 15
Flow factor methods
Is there an appropriate catchment model?
No
Yes
Water Resource Planning processes(See Environment Agency guidelines)
Does climate change triggermajor investment?
Yes
No
END
Use hydrological or hydrogeological models
More detailed work-select appropriate
methods?
FLOW FACTOR METHOD 1bApply ‘regionalised’
flow/recharge factors
START
Was the catchment modelled
in this project
Yes No
Simplified Method
Option to use modelled percentiles or ‘simplified method’
based on mean changeand standard deviation
FLOW FACTOR METHOD 1aApply flow/recharge factors
for modelled catchments
Consult with EA
FLOW FACTOR METHOD 1cApply re-sampling techniques
Calculate flow/recharge indicatorsSelect flow/recharge time series
‘Park’ impacts assessment
Page 16
Rainfall-runoff methods
RAINFALL-RUNOFF METHODS
2b. Useperturbed time series
based on ‘UKWIR06’scenarios Section 3.9
Spreadsheet: Report CD-Rom
Water Resources Planning processes(See Environment Agency guidelines)
2c. Re-sampling
based on the ‘UKWIR06’scenarios
Section 3.10
Does climate change triggermajor investment?
YesNo
END
Run models for historical and changed climates(100-1000s runs)
2a.Use
perturbed time series based on ‘UKCIP02’
scenarios (Optional)Section 3.8
Spreadsheet: Report CD-Rom
Run models for historical and changed climates(7-8 runs)
3. Advanced
methods
Section 3.12
Any benefits of
further analysis?
Yes
No
START
#
Page 17
Climate scenario data
Page 18
Outputs – Thames at Kingston flow factors
Change in flow (2020s)
-50
-40
-30
-20
-10
0
10
20
30
Jan
Feb Mar Apr
May Ju
n
Jul
Aug
Sep Oct
Nov
Dec
Q95
Perc
en
t cha
ng
e
5 25 50 75
95 Median Dry Scenario Wet Scenario
What have water companies done?
Page 20
Water company activity on climate change
•OFWAT Climate Change Policy
•EA Environment Vision���� Sector Adaptation Plans ���� R&D
•Water UK ���� UKWIR R&D
•Water company Strategic Direction Statements (SDS)
•Final Water Resources Plans (PR09)
•Drought Plans
•Flood resilience, asset deterioration etc……..
Page 21
OFWAT Climate Change Policy
http://www.ofwat.gov.uk/sustainability/climatechange/pap_pos_climatechange.pdf
Page 22
Some key links
EA Water Resources Planning Guidelines
http://www.environment-
agency.gov.uk/business/sectors/39687.aspx
OFWAT
http://www.ofwat.gov.uk/sustainability/climatechange/
pap_pos_climatechange.pdf
Water UK
http://www.water.org.uk/
Covers water resources plans and climate change
adaptation actions
Page 23
Water company approach impacts assessment
An integrated approach to examine impacts on:
1. Water supply (Deployable Outputs)
• Surface water
• Groundwater
2. Demand for water
3. Asset deterioration
4. Water quality
5. Drought prediction & management
Page 24
Impacts of climate change on average demand
(pcc)
4.0%Dry
2.6%Mid
1.3%Wet•Higher than in PR04 (0.8-
2.7%)
•Higher than CCDEW (0.9-
1.8 %)
•A better estimate based
on local data, more
climate models and
consistent with supply
side
Page 25
Drilling down
���� Zones 2 and 3, both large rural areas.
���� Detached����Bungalow ���� Semi-detached ���� Terraced. Flats
���� MOSAIC groups A (‘Symbols of Success’) and F (‘Welfare Borderline’), the most and least affluent respectively
���� Good relationships also exist for groups C (‘Suburban Comforts’) and E (‘Urban Intelligence’).
⌦⌦⌦⌦ No significant relationship existed for the other two groups B (‘Happy Families’) and D (‘Ties of Community’)
0
50
100
150
200
250
300
350
0 5 10 15 20 25
Mean monthly temperature (degC)
Pe
r c
ap
ita
de
ma
nd
(l/
h/d
)
WRZ 1
WRZ 2
WRZ 3
WRZ 4
WRZ 5
0
50
100
150
200
250
300
350
0 5 10 15 20 25
Mean monthly temperature (degC)
Pe
r c
ap
ita
de
ma
nd
(l/
h/d
)
Property type B
Property type D
Property type F
Property type S
Property type T
0
50
100
150
200
250
300
350
0 5 10 15 20 25
Mean monthly temperature (degC)
Pe
r c
ap
ita
de
ma
nd
(l/
h/d
)
MOSAIC class A
MOSAIC class B
MOSAIC class C
MOSAIC class D
MOSAIC class E
MOSAIC class F
Page 26
Other aspects of Supply Demand Balance
• Supply v demand (AADY, CPDY)
• - Sustainability ‘Losses’
• Proposed environmental investment
programme
• Reduce pollution from discharges
• Change abstraction licences in
sensitive areas
• WFD
• - Outage
• +/- Headroom
• Leakage is part of demand and
managed through targets
Page 27
Other aspects of Supply Demand Balance
Risks and Uncertainty
S1 Vulnerable surface water
licences
S2 Vulnerable groundwater
licences
S3 Time Limited Licences
S4 Bulk transfers
S5 Gradual pollution of sources
causing a reduction in abstraction
S6 Accuracy of supply side data
S7 Sustainability Issues
S8 Uncertainty of impact of
climate change on source yields
S9 Uncertainty over New
Sources
-4
0
4
8
12
2002 2007 2012 2017 2022 2027 2032Year
Headro
om
Uncert
ain
ty (
Ml/d)
10% to 20% 20% to 30% 30% to 40% 40% to 60% 60% to 70%
70% to 80% 80% to 90% Mean new method old method
D1 Accuracy of sub-component data
D2 Demand forecast variation
D3 Uncertainty of impact of climate
change on demand
D4 Uncertainty of impact of
demand management
Page 28
100
110
120
130
140
150
160
170
180
190
200
Ml/d
Demand
Demand 149.1 149.8 150.1 151 151.7 153 153.6 154.8 155.4 156.5 157.1 158.9 159.9 161.7 162.6 164.4 165.4 167.6
2003-
04
2005-
06
2006-
07
2008-
09
2009-
10
2011-
12
2012-
13
2014-
15
2015-
16
2017-
18
2018-
19
2020-
21
2021-
22
2023-
24
2024-
25
2026-
27
2027-
28
2029-
30
Page 29
(Average Baseline)
100
110
120
130
140
150
160
170
180
190
200
Ml/d
Total Resources Demand
Total Resources 173.9 165.6 165.5 165.2 165.1 159.7 159.6 159.3 159.2 158.9 158.8 158.6 158.4 158.2 158.1 157.8 157.7 157.4
Demand 149.1 149.8 150.1 151 151.7 153 153.6 154.8 155.4 156.5 157.1 158.9 159.9 161.7 162.6 164.4 165.4 167.6
2003-
04
2005-
06
2006-
07
2008-
09
2009-
10
2011-
12
2012-
13
2014-
15
2015-
16
2017-
18
2018-
19
2020-
21
2021-
22
2023-
24
2024-
25
2026-
27
2027-
28
2029-
30
Page 30
(Average Baseline)
100
110
120
130
140
150
160
170
180
190
200
Ml/d
Total Resources
Demand
Dmd + Headroom
Total Resources 173.9 165.6 165.5 165.2 165.1 159.7 159.6 159.3 159.2 158.9 158.8 158.6 158.4 158.2 158.1 157.8 157.7 157.4
Demand 149.1 149.8 150.1 151 151.7 153 153.6 154.8 155.4 156.5 157.1 158.9 159.9 161.7 162.6 164.4 165.4 167.6
Dmd + Headroom 154.6 155.6 156.2 157.2 157.9 159.3 160 161.2 161.9 163 163.6 165.5 166.5 168.4 169.3 171.1 172.2 174.5
2003-
04
2005-
06
2006-
07
2008-
09
2009-
10
2011-
12
2012-
13
2014-
15
2015-
16
2017-
18
2018-
19
2020-
21
2021-
22
2023-
24
2024-
25
2026-
27
2027-
28
2029-
30
Page 31
Final Plan – with measures 1Ml/d yield = £
2million
140
150
160
170
180
190
200
Ml/d
Total Resources
Demand
Dmd + Headroom
Total Resources 173.85 161.21 159.62 158.89 158.09 157.34 159.5 160.76 161.1 160.1 165.76 174.32 173.59 172.86 172.14 171.33 170.35 169.59 168.46 167.56 171.9 170.82 169.95 174.94 176.11 173.05 174.18
Demand 149.11 149.43 149.74 150.09 150.5 150.92 151.57 152.21 152.9 153.51 154.09 154.67 155.26 155.86 156.34 156.92 157.7 158.65 159.64 160.54 161.42 162.32 163.19 164.07 165.13 166.2 167.29
Dmd + Headroom 154.63 155.12 155.59 156.1 156.68 157.14 157.81 158.49 159.21 159.85 160.46 161.07 161.7 162.33 162.84 163.45 164.26 165.25 166.26 167.2 168.11 169.04 169.95 170.86 171.95 173.05 174.18
2003-
04
2004-
05
2005-
06
2006-
07
2007-
08
2008-
09
2009-
10
2010-
11
2011-
12
2012-
13
2013-
14
2014-
15
2015-
16
2016-
17
2017-
18
2018-
19
2019-
20
2020-
21
2021-
22
2022-
23
2023-
24
2024-
25
2025-
26
2026-
27
2027-
28
2028-
29
2029-
30
Minor improvements
Sustainability Loss
Major resource development
Effluent re-use
or desalinisation
Demand management
Leakage reduction
Climate change
Changing balance of imports/exports
Page 32
Review of water quality impacts
Thames at Bray Intake
Determinand Comments
BOD Apart from a very few isolated values would achieve high
WFD status.
Ammonia General consistent quality over past 10 years. Would
achieve high WFD status.
TON No clear trend. All values exceed SWAD A1 guideline.
Orthophosphate Improvement in quality since 1999, but still have annual
variability. Would not achieve good WFD status.
HCH Gamma Very low values since 2000
Dieldrin Values at detection level since 2001
Parathion Values at detection level since 2001, although 2007 value
showed an increase
Oxygen (%sat) No trend. Would achieve high WFD status for whole
period.
Oxygen (mg/l) All values > 8 mg/l.
Page 33
Scoping risks by water resource zone
Resource
Zone Source type
Aver
age
DO
Ml/d
Nitra
te
Phosp
hat
e
Turb
idity
Pes
tici
des
Chlo
rophyll
Sal
inity
Direct
Small
reservoir
Unknown Surface
Large
reservoir
LGS 1.20
Chalk
RZ1
Groundwater
Other 32.73
D irect 8.8 3
Sm all
reservo ir
Surface
L arge reservo ir
13 .05
L G S 7.8
C halk 23 .09
RZ 3
G ro u nd w at er
O th er 14 .31
Page 34
Asset deterioration – leakage
0
50
100
150
200
250
300
350
400
1 61 121 181 241 301
Months
Ho
urs
HadCM3 CGCM2 CSIRO-mk2GFDL-R30 CCSR/NIES ECHAM4/OPYC3Wet Mid Dry
-5
0
5
10
15
20
25
1 61 121 181 241 301
Months
Me
an
te
mp
era
ture
(c
els
ius
)
HadCM3 CGCM2 CSIRO-mk2GFDL-R30 CCSR/NIES ECHAM4/OPYC3Wet Mid Dry
0
5
10
15
20
25
30
1 61 121 181 241 301
Months
Fro
st
da
ys
HadCM3 CGCM2 CSIRO-mk2GFDL-R30 CCSR/NIES ECHAM4/OPYC3Wet Mid Dry
•Climate influences
leakage
•Temperature
•Sunshine hours
•Frost days
•Case for investment in
new pipes
Page 35
Conclusions: Impacts of climate change on
UK water resources
• Supply • Wetter and warmer winters & drier, warmer summers & increase frequency of
short rainfall droughts
• Increase in mean winter flow but a reduction summer flows and autumn and spring flows in some catchments (dependent on PET). No change in annual average recharge
• Range of results from different climate & hydrology models
• Catchment response & water resources impact depend on catchment/system characteristics
•Supply-Demand Balance• Climate change will increase demand by 1-4% and reduce supply by around 5-
20% by 2020s
•Environment protected by WFD and other legislation?
•Adaptation • Bring forward investment in supplies winter storage, effluent re-use,
desalination and effluent re-use and demand management
• Possible bias towards demand side measures?
• More resilient supplies or better drought management?
• Factor climate change/variability into other policies
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Conclusions: methods
•Methods are suitable for rapid assessments at national and European scales
•Climate scenarios require updating to FAR models, Ensembles, UKCP09
•Water industry asked for probabilistic scenarios –what next?
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Example project reports & research papers
Vidal, J.P. and Wade, S.D. (2007). A framework for developing high-resolution multi-model climate projections: 21st century scenarios for the UK. Int. J. Climatology (accepted).
Vidal, J.P. and Wade, S.D. (2007). Multimodel projections of catchment-scale precipitation regime. J. Hydrology (submitted).
Vidal, J.P. and Wade, S.D. (2007) Effects of climate change of river flows and groundwater recharge: Guidelines for resources assessments and UKWIR06 scenarios. UKWIR Report 05/CL/04/*
Wade, S.D., Barnett, C. and Fenn, T. (2006). Climate change and water resources. Defra Cross-Regional Climate Change Impacts and Adaptation Research Programme: Topic C – Water.
Wade, S.D., Jones, P.D. and Osborn, T. (2006). The impacts of climate change on severe droughts. Implications for decision making. Environment Agency Science Report: SC040068/SR3.