Introduction to water resources impacts modelling Erika Coppola, ICTP, Trieste [email protected].

44
troduction to water resources impacts modell Erika Coppola, ICTP, Trieste [email protected]

Transcript of Introduction to water resources impacts modelling Erika Coppola, ICTP, Trieste [email protected].

Introduction to water resources impacts modellingErika 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

– 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

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

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

Rapid Change in Global Demographics

Source: United Nations, 1996

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

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

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 (%)

Uncertainty in simulationsNumber of models in agreement

of an increase in runoff

Catchment-scale Seasonal Runoff

The Liard The Okavango The Yangtze

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

Thanks!