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• Impact modelling: Vulnerability and adaptation with respect to water resources
• Hydrologic implications of climate change for water resources
• Focus of the school• Uncertainty in a Climate Change
scenario
• Defining V&A assessment– Often V&A is analysis, not
assessment– Why? Because the focus is on
biophysical impacts, e.g., hydrologic response, crop yields, forests, etc.
• However, assessment is an integrating process requiring the interface of physical and social science and public policy
Examples of Adaptation –
Water Supply• Construction/modification of physical infrastructure
– Canal linings– Closed conduits instead of open channels– Integrating separate reservoirs into a single system– Reservoirs/mydroplants/delivery systems– Raising dam wall height– Increasing canal size– Removing sediment from reservoirs for more
storage– Interbasin water transfers
Examples of Adaptation – Water Supply (continued)
• Adaptive management of existing water supply systems
– Change operating rules– Use conjunctive
surface/groundwater supply– Physically integrate reservoir
operation system– Coordinate supply/demand
Examples of Adaptation – Water Supply (continued)
• Policy, conservation, efficiency, and technology– Domestic
• Municipal and in-home re-use• Leak repair• Rainwater collection for nonpotable uses• Low flow appliances• Dual supply systems (potable and nonpotable)
– Agricultural• Irrigation timing and efficiency• Lining of canals, closed conduits• Drainage re-use, use of wastewater effluent• High value/low water use crops• Drip, micro-spray, low-energy, precision
application irrigation systems• Salt-tolerant crops that can use drain
water
Examples of Adaptation –
Water Supply (continued)• Policy, conservation, efficiency, and
technology (continued)– Industrial
• Water re-use and recycling• Closed cycle and/or air cooling• More efficient hydropower turbines• Cooling ponds, wet towers and dry towers
– Energy (hydropower)• Reservoir re-operation• Cogeneration (beneficial use of waste heat)• Additional reservoirs and hydropower stations• Low head run of the river hydropower• Market/price-driven transfers to other
activities• Using water price to shift water use between
sectors
Tools in Water Resource V&A Studies
• Hydrologic models (physical processes)– Simulate river basin hydrologic processes– Examples – water balance, rainfall-runoff,
lake simulation, stream water quality models
• Water resource models (physical and management)– Simulate current and future supply/demand
of system– Operating rules and policies – Environmental impacts– Hydroelectric production– Decision support systems (DSS)
for policy interaction• Economic models
Snow Accumulation
Precipitation
Sublimation
Snowmelt Runoff
Evaporation
Recharge
Infiltration
Evapotranspiration
SurfaceRunoff
Groundwater flow
Discharge
Mountain FrontRecharge
SurfaceRunoff
Discharge
Studying the Hydrologic Cycle at Various Scales
Globally: 86% of Evap. and 78% of Precip. occur over the Globally: 86% of Evap. and 78% of Precip. occur over the oceans oceans
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Two Primary Water Resources/Hydrology Challenges:
• Hydrologic Hazards ( Floods and Droughts)
• Water Supply Requirements ( Quantity and Quality)
“General” and Widespread Floods
Bangladesh floods in 2004
August 19, 1993
August 14, 1993
Mississippi RiverMissouri River
Illinois River
MISSISSIPPI Floods 1993
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Drought most visible in falling reservoir levels
Lake Powell, Colorado River, USA
Normal Years
Recent SouthwestDrought 2004
Source: J. Kane SRP 2004
Climate Change and Hydrologic Implications
• Precipitation amount– Global average increase – Marked regional differences
• Precipitation frequency and intensity– Less frequent, more intense (Giorgi et al.,
2011;Trenberth et al., 2003)
• Evaporation and transpiration– Increase total evaporation
Climate Change and Hydrologic Implications
(continued)• Changes in runoff– Despite global precipitation increases,
areas of substantial runoff decrease• Coastal zones
– Saltwater intrusion into coastal aquifers– Severe storm-surge flooding
• Water quality– Lower flows could lead to higher
contaminant concentrations– Higher flows could lead to greater leaching
and sediment transport
Global Global WWarming And Hydrologic Cycle arming And Hydrologic Cycle ConnectionConnection
Heating
Temperature Evaporation
Water Holding Capacity
Atmospheric Moisture
Temperature oFSat
ura
ted
Vap
or
Pre
ssu
re
t t+20
Green House Effect
Rain Intensity
Drought Flood
FloodDrought
Created by: Gi-Hyeon Park
The Recent Drought in Historical Context:
Reconstruction of Proxy records:
- Analysis of Tree Rings and Stable Isotopes
How Extreme Can it Get ?????
Sept 1951 Elephant Butte, NM Jan 2003Middle Rio Grande Basin, NM AD Grissino-Mayer, Baisan,
Morino, & Swetnam, 2001
Late 16th centMegadrought
GreatDrought
Highlyvariable
1250 1350 1450 1550 1650 1750 1 850 1950 2050 2150 2250 2350 2450 2550 2650 2750
Rec
on
stru
cted
PD
SI
-
-
-
-
-
-
-
-
-
2.0
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-2.0
Past Present Future
Recent US Southwest Drought in Historical Context
Two Primary Water Resources/Hydrology Challenges:
• Hydrologic Hazards ( Floods and Droughts)
• Water Supply Requirements ( Quantity and Quality)
Projected Regions of Water Stress
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Distribution of Fresh Water Use
90.8 33.4%
17.1%
49.5%
460
7.0%6.0%
87.0%
36.47
18.6%
22.0%59.4%
117
60.0%17.0%
23.0%
467.34
45.2%
13.1%
41.7%
380
4.0% 3.0%
93.0% Agriculture
Industry
Domestic
Fresh Water Use(109 Cubic Meters)
Water Source
Water Use
USA China India
Russia Japan Brazil
92%6%
2%
70.3Iran
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
-10%
0%
10%
20%
30%
40%
50%
60%
70%
80%
Asia
Europ
e
Midd
le Eas
t & N
orth
Afri
ca
Sub-S
ahar
an A
frica
North
Am
erica
Centra
l Am
erica
& C
aribb
ean
South
Am
erica
Ocean
ia
Wor
ld
Pro
ject
ed P
opu
latio
n In
crea
se 2
000-
202
5
26%
-4%
52%
71%
17%
36%33%
30% 29%
Projected Population Growth Distribution
1995 world population
5.7 Billion
2025 Projection
8.3 Billion
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Our projections of future water use have been flawed.
0
2000
4000
6000
8000
10000
12000
14000
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
Cub
ic K
ilom
eter
s pe
r Y
ear
Actual Global Water Withdrawals
Projections
SOURCE: Dr. Peter H. Gleick, Pacific Institute for Studies in Development
Population Without Access to Improved Water Supply: 2000
300
693
783 26
0
100
200
300
400
500
600
700
800
Africa Asia Lat.Amer/Carib. Oceania Europe
Mill
ion
peop
le Total: 1,100 million
SOURCE: Dr. Peter H. Gleick, Pacific Institute for Studies in Development
Hydrology Model• Critical questions
– How does rainfall on a catchment translate into flow in a river?
– What pathways does water follow as it moves through a catchment?
– How does movement along these pathways impact the magnitude, timing, duration, and frequency of river flows?
Data Requirements• Prescribed supply (riverflow given as
fixed time series)
– Time series data of riverflows (headflows) cfs
– River network (connectivity)• Alternative supply via physical hydrology
(watersheds generate riverflow)
– Watershed attributes• Area, land cover . . .
– Climate• Precipitation, temperature,
windspeed, and relative humidity
Data Requirements (continued)
• Water demand data– Municipal and industrial demand
• Aggregated by sector (manufacturing, tourism, etc.)
• Disaggregated by population (e.g., use/capita, use/socioeconomic group)
– Agricultural demands• Aggregated by area (# hectares, annual
water-use/hectare)• Disaggregated by crop water requirements
– Ecosystem demands (in-stream flow requirements)
Calibration and Validation• Model evaluation criteria
– Flows along mainstream and tributaries
– Reservoir storage and release– Water diversions from other basins– Agricultural water demand and
delivery– Municipal and industrial water
demands and deliveries– Groundwater storage trends and
levels
Uncertainty in climate change impact assessment in water
resources
• Global climate models (GCMs) use different but plausible parameterisations to represent the climate system.
• Sometimes due to sub-grid scale processes (<250km) or limited understanding.
Uncertainty in climate change impact assessment
• Therefore climate projections differ by institution:
2°C
Multiple ensembles for various prescribed temperature changes
9 model runs
Simon Gosling, Walker Institute for Climate System Research, University of Reading
Global Average Annual Runoff
The ensemble mean
But what degree of uncertainty is there?
Global Average Annual Runoff Change from Present (%)
Seasonal Runoff
Agreement of increased snow-melt induced runoff
Agreement of dry-season becoming drier
Less certainty regarding wet-season changes
Large uncertainty throughout the year
What can we do to decrease the uncertanty
• Further downscaling: Regional climate modelling
• Bias correction techniques
• ENSEMBLE approach:Dynamical
downscalingStatistical
downscaling
VALUE European COST
project
Ensuring Water in a Changing WorldEnsuring Water in a Changing World
International Water Cycle Research International Water Cycle Research Initiatives Addressing These Issues:Initiatives Addressing These Issues:
- WCRP - WCRP (GEWEX, CLIVAR, CLiC)(GEWEX, CLIVAR, CLiC)
- UNESCO Initiatives - UNESCO Initiatives (PUB, HELP)(PUB, HELP)
- And Many National Programs- And Many National Programs
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
P
E
Qs
Ss
Sg
Qg
Ig
Coupled Ocean-Atmosphere Models
Mesoscale Models
SVATs
Hydrologic/Routing Models
Water Resources Applications
GEWEX
CLIVAR
Hydrologic Services
Water resources management agencies
GEWEX Role in Climate ResearchGEWEX Role in Climate Research
CLiC
Monsoon Processes
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
MODEL
PARAMETERESTIMATION
DATA
If the “World” of Watershed Hydrology Was Perfect!
Requirements and State of Hydrologic Forecasting
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine