Transcript Coppola_Intro_WR

Introduction to water resources impacts modelling
Erika Coppola, ICTP, Trieste
[email protected]
• 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
•
•
•
•
•
•
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
– Energy (hydropower)
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
Studying the Hydrologic Cycle at Various
Scales
Evapotranspiration
Sublimation
Evaporation
Snow Accumulation
Mountain
Front
Recharge
Precipitation
Discharge
Snowmelt Runoff
Infiltration
Groundwater flow
Surface
Runoff
Surface
Runoff
Discharge
Recharge
Globally: 86% of Evap. and 78% of Precip. occur over the
oceans
Distribution of Freshwater
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
Illinois River
August 14, 1993
Mississippi River
Missouri River
August 19, 1993
Bangladesh floods in 2004
MISSISSIPPI Floods 1993
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Drought most visible in falling reservoir
levels
Normal Years
Recent Southwest
Drought 2004
Lake Powell, Colorado River, USA
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 Warming And Hydrologic Cycle
Connection
Heating
Drought
Saturated Vapor Pressure
Temperature
Flood
t
t+20
Evaporation
Water
Holding
Capacity
Atmospheric
Moisture
Green
House
Effect
Rain
Intensity
Temperature oF
Drought
Created by: Gi-Hyeon Park
Flood
How Extreme Can it Get ?????
The Recent Drought in Historical Context:
Reconstruction of Proxy records:
- Analysis of Tree Rings and Stable Isotopes
Recent US Southwest Drought in Historical Context
Sept 1951
Elephant Butte, NM
Jan 2003
Grissino-Mayer, Baisan,
Morino, & Swetnam, 2001
Reconstructed PDSI
Middle Rio Grande Basin, NM AD
2.0
-
1.5
-
1.0
-
0.5
-
0
-
-0.5 -1.0 -
Great
-1.5 Drought
-2.0 1250
Past
1350
Late 16th cent
Megadrought
1450
1550
1650
1750
Highly
variable
1 850
1950
2050
Present
2150
2250
2350
2450
2550
2650
2750
Future
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
460
467.34
USA
Water Source
China
380
7.0%
India
6.0%
Fresh Water Use
(109 Cubic Meters)
4.0% 3.0%
41.7% 45.2%
Water Use
87.0%
13.1%
Agriculture
93.0%
Domestic
Industry
Russia
117
Japan
Brazil
36.47
23.0%
17.0%
Iran
70.3
60.0%
18.6%
90.8
33.4%
49.5%
59.4%
92%
22.0%
17.1%
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
6%
2%
Projected Population Growth
Distribution
1995 world population
5.7 Billion
80%
71%
70%
2025 Projection
8.3 Billion
60%
52%
50%
40%
30%
36%
26%
33%
30%
17%
20%
10%
-4%
0%
-10%
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
29%
Cubic Kilometers per Year
Our projections of future water use
have
been
flawed.
14000
12000
10000
Projections
8000
6000
Actual Global Water Withdrawals
4000
2000
0
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
SOURCE: Dr. Peter H. Gleick, Pacific Institute for Studies in Development
Rapid Change in Global Demographics
Source: United Nations,
1996
Population Without Access to Improved Water Supply: 2000
800
693
700
Million people
600
Total: 1,100 million
500
400
300
300
200
78
100
3
0
Africa
Asia
Lat.Amer/Carib.
Oceania
SOURCE: Dr. Peter H. Gleick, Pacific Institute for Studies in Development
26
Europe
The school focus
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
Final Aim of our exercise
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
Simon Gosling, Walker Institute for Climate System Research, University of Reading
9 model runs
Global Average Annual Runoff
The
ensemble
mean
Global Average Annual Runoff Change from Present (%)
But what degree of uncertainty is there?
Uncertainty
in
simulations
Number of models in agreement
of an increase in runoff
Catchment-scale Seasonal
Runoff
The Liard
The Okavango
The Yangtze
Seasonal Runoff
Agreement of increased snowmelt induced runoff
Less certainty
regarding
wet-season
changes
Agreement of dryseason becoming
drier
Large uncertainty throughout
the year
What can we do to
decrease the uncertanty
• Further
downscaling:
Regional climate
modelling
• Bias correction
techniques
• ENSEMBLE
approach:
Dynamical
downscaling
Statistical
downscaling
VALUE
European COST
project
Ensuring Water in a Changing World
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
International Water Cycle Research
Initiatives Addressing These Issues:
- WCRP (GEWEX, CLIVAR, CLiC)
- UNESCO Initiatives (PUB, HELP)
- And Many National Programs
GEWEX Role in Climate Research
CLiC
CLIVAR
Water Resources
Applications
Coupled
Ocean-Atmosphere
Models
Water resources
management agencies
Mesoscale
Models
E
Hydrologic/Routing
Models
P
Qs
Monsoon
ProcessesSVATs
D Ss
Ig
D Sg
Qg
GEWEX
Hydrologic Services
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Requirements and State of Hydrologic
Forecasting
DATA
MODEL
PARAMETER
ESTIMATION
If the “World”
of Watershed
Hydrology Was
Perfect!
Source: Soroosh Sorooshian Center for Hydrometeorology and Remote Sensing University of California Irvine
Thanks!