2. WATER DISASTER PREVENTION (40 min.)

WATER DISASTER PREVENTION WATER DISASTER PREVENTION focused on floods and droughts focused on floods and droughts

INFORMATION LECTUREINFORMATION LECTURE

SUMMER SCHOOL/WORKSHOP

Prof. Pavel KOVARCULS Prague

WATERWATER RESOURCESRESOURCES MANAGEMENT MANAGEMENT

PROTECTION OF WATER RESOURCESPROTECTION OF WATER RESOURCESPROTECTION OF SOCIETY AGAINST WATER EXTREMES PROTECTION OF SOCIETY AGAINST WATER EXTREMES

INTEGRATED WATER RESOURCES MANAGEMENT: INTEGRATED WATER RESOURCES MANAGEMENT: DUBLINS PRINCIPES (1992):DUBLINS PRINCIPES (1992):• FRESH WATER IS AN EXHAUSTIBLE AND VULNERABLE FRESH WATER IS AN EXHAUSTIBLE AND VULNERABLE RESOURCESRESOURCES• PARTICIPATION OF ALLPARTICIPATION OF ALL• WATER AS AN ASSET WATER AS AN ASSET • IMPORTANT ROLE OF WOMENIMPORTANT ROLE OF WOMEN

WATER REQUIREMENTS

AVAILABLE RESOURCES

STATUS OF WORLD FRESH WATER STATUS OF WORLD FRESH WATER AVAILABILITYAVAILABILITY

PARAMETR

STATUS

1997 2050

POPULATION* (in billions) 5.8 9.8

POPULATION AFFECTED BY WATER SCARCITY (in millions)

170 1700

COUNTRIES AFFECTED BY WATER SCARCITY

18 39

* * Medium population projectionMedium population projectionSource: Gardner and Engelman, 1997Source: Gardner and Engelman, 1997Note: Note: Some other sources may have have a different viewSome other sources may have have a different view

Floods & Droughtskilled 450 thousands peopleaffected 1,5 bilions people

Floods & Droughts80% of all catastrophesDamage of 370 bilions USD

REASONS FOR FLOODSREASONS FOR FLOODS

• HYDROMETEOROLOGICAL SITUATION SMALL CATCHMENTS:TORRENTIAL RAINFALLS LARGE CATCHMENTS: COMBINATIONS OF REGIONAL AND TORRENTIAL RAINFALLS

Most important criteria: Depth P (mm) and Intensity i (mm.min-1) of rainfall.

• ANTECEDENT SATURATION OF THE UPPER SOIL ZONE ANTECEDENT PRECIPITATION INDEX API (mm) –in 30 previous days SOIL MOISTURE DEFICIT SMD (mm) – continously

• MEASURES FOR INCREASING RETENTION / ACCUMULATION OF WATER

= DECREASING DIRECT (SURFACE) RUNOFF:Land use, landscape structure, erosion control measures, soil management, water management: natural depressions, retention barriers, (fish)ponds, channel+inundations together (dikes and polders). Weirs and dams?

HOW TO LIVE WITH FLOODSCASE STUDY: Czech Republic,

August 2002

FLOOD in PRAGUE 2002 Situation: Two heavy rain periods: 6 - 7/8/2002 (250mm) 11-12/8/2002 (200mm) (Cyclon from Mediterranean area over the Alps blocked above Central Europe by the high pressure area on

Baltic region)

Rivers: Vltava river + tributaries: Berounka river- last) 14 August 2002 meeting of them

(Vltava has the cascade of dams)

Catastrophe: Qmax=5 300 m3.s-1 (Q500) , 15 people killed , 4 billions EUR

REAL FLOODSREAL FLOODS

(rainfall, surface runoff)(rainfall, surface runoff)The flow rates et the main water-stages above and in Prague.

VSmax = 785 cm

cca 5300 m3.s-1

VSmax = 796 cm

cca 1800 m3.s-1

VSmax = 467 cm

cca 440 m3.s-1

Qmax = cca 3500 m3.s-1

0

1000

2000

3000

4000

5000

6000

8.8.2002 9.8.2002 10.8.2002 11.8.2002 12.8.2002 13.8.2002 14.8.2002 15.8.2002 16.8.2002 17.8.2002 18.8.2002

source ofthe data CHM I

Q (

m3 .s

-1)

Vltava - Malá Chuchle Berounka - Beroun Sázava - Nespeky VD Vrané - balance outflow

note: The input data are compile by water authority Povodí Vltavy based on operative data. This data might be further modify after detailed evaluation by The Czech Hydrometeorological Institute.

Trója - Císařský ostrov - ÚČOVTrója - Císařský ostrov - ÚČOV

Preparations of flood protection measuresPreparations of flood protection measures

Flood preventionFlood prevention

Flood effectivenessFlood effectiveness

FLOODS Five types of measures:• Early warning: Information, Warning: four elements of people centred warning systems:

- Risk knowledge (systematically data collection) - Monitoring & warning service - Communicate risk information- dissemination - Response capability (reaction to warning)

• Pre-flood measures: Last time physical prevention: - evacuation - sand sack providing - mobile gates installation

• Rescue execution: Continuing flood forecast and warning, rescue team- evacuation, housing and dormitory facilities

• Post – flood measures: flood water drainage, pumping, drying

• Long-time measures:

Technical: Flood areas zoning, technical measures from: land use changes via: river discharge capacities increasing to: diking, poldering, reservoirs and dams operation Legislative: EU and national WF Directives, reimburses of flood damages, insurance companies involvement, training of integrated teams (firemen, police,health service, civil service, volunteers,etc.)

BASIC ISSUES FOR EFFECTIVE FLOOD CONTROL

• To increase natural water retention capacityInterrupting surface runoff, decrease water velocity, linking river channel with flood plain (inundation)

• To build technical measuresPoldering and diking, mobile gates in urbanised areas, dams and reservoirs.

• To develop flood prevention systemFlood zoning (land planning and management), Role of government, civil service, municipality, owners.Early warning system.

HOW TO MITIGATE FLOOD IMPACTS(High impact public issues)

FLOOD PREVENTION STRATEGYFLOOD PREVENTION STRATEGYStructural measures:Building flood protection systems• Increasing retention capacities (hydraulic structures)• Protecting urbanised areas• Protecting water management infrastructure Non-structural measures:Applying non-investment costs• Operational flood control plans, early warning systems, info to inhabitants• Risk knowledge, systematic data collection and processing (models)• Flood areas zoning determination• Training of integrated teams

MANAGEMENT CONTROL PRACTICESMANAGEMENT CONTROL PRACTICES(Flood & Erosion Control)

• Vegetation cropping (dense canopy, growing duration, effect of interception, mulch, effectiveness)

• Soil management (deep ploughing, contour tillage, strip cropping)

• Headwater management (field storage, terracing, ditch storage, small ponds, winter lagoons, gully control, torrent control)

• Management in water-protected areas-water for drinking purposes: Protective zones - 1st: 30 m to 200 m, closed by fence (no agriculture), no entrance - 2nd: 200m to 1 or 2 km, limited use (no concentrated animal husbandry, organic

farming only)

• strip croppingstrip cropping

Agronomic erosion controlAgronomic erosion control

• terracesterraces

TECHNICAL EROSION CONTROLTECHNICAL EROSION CONTROL

• GullyGully/torrent/torrent control control

DEFINITIONS OF DROUGHTSDEFINITIONS OF DROUGHTSCLIMATE VARIATIONS

PRECIPITATION DEFICIT HIGH TEMPERATURES

INFILTRATION DECREASE EVAPORATION INCREASE

SOIL MOISTURE DEFICIT

PLANT STRESS

GROUNDWATER STORAGE DECREASE

RUNOFF DECREASE

ECONOMIC, SOCIAL AND ENVIRONMENTAL CONSEQUENCES

Meteorologicdrought

Agriculturaldrought

Hydrologicdrought

Trends in soil moisture content (AW) during rainless periods

Drought analysis – Depletion curves

DROUGHT ASSESSMENT METHODS

• Return period of drought (Q364 , Q355) with consideration of drought duration

• Depletion curve construction• Exceeding curves of runoff deficits and deficit

period duration

DROUGHT CONTROL PRACTICES• Rainwater harvesting and storing• Growing less water-requiring crops• Irrigation systems (drip irrigation)• Brakish/saline water desalination and use• Groundwater use (for drinking purposes only)

CAN WE QUANTIFY IMPACTS OF CLIMATE CHANGE ON WATER REGIMES?

Arguments clearly recognising climate change: • Increase of temperature (0.6°C in the last 100 years)

• Increase of greenhouse gases concentration (CO2, N2O, CH4, etc.)- depending on localities

• Increasing number of natural disasters

Opinions admitting climate variations only:• Statistical analyses are often based on assumptions and exeggerated (see

B.Lomborg:“Sceptic Environmentalist“)• Disaster risk from taifoons (Asia) and hurricanes (America) do not exceed

previous historical catastrophes• Future economic development will be more regional than global

CLIMATE CHANGEEURURALIS Scenarios

Since 1800 CO2 concentrations increased by 30%, CH4 by 150% , N2O by 20%.Prognosis to 2100 global temperature increase by 1,9°C to 4,3°Cdepending on the scenario:

Global A1 B1 Global Economy Global co-operation (rapid economic growth) (service & info-based economy)

A2 B2 Continental Market Regional Communities

(heterogeneous world) (social & envi sustainability)

Regional

Low

reg

ulat

ion

Hig

h R

egul

atio

n

POSSIBLE IMPACTS OF CLIMATE CHANGE IN WATER POSSIBLE IMPACTS OF CLIMATE CHANGE IN WATER RESOURCESRESOURCES

TEMPERATURE INCREASE

PRECIPITATION VARIABILITY DECREASEINCREASE

INCREASE OF FLOOD FREQUENCY AND INTENSITY INCREASE OF DRY PERIODS

DURATION AND DROUGHT STRESS

DEGRADATION OF SOIL SURFACE, EROSION

DESERTIFICATION

AGRICULTURAL/FORESTRY PRODUCTIVITY DECREASE FOREST BURNING LOSS OF BIODIVERSITY MALNUTRITION AND FAMINE POVERTY

INCREASE SEDIMENTS IN RIVERS

INCREASE OF SILTATIONIN RESERVOIRS

DECREASE OF MANAGABLE WATER RESOURCES

DECREASE OF RE- SERVOIR LIFE TIME AND INCREASE OF MAINTENANCE COST

RISK ASSESSMENTRisk = Chance . Damage

Chance: Hydrologic computation of N-year water level

Damage: Tangible: real estate damage, and/or Intangible: environmental damage, loss of

confidence in authorities (incl. government, etc.)

Note 1: Inssurance companies take this seriously in many countries. It is one effective tool that does not allow to rebuilt houses on the same site („active zone“ on flooding areas)

Note 2: The risk assessment method for droughts is not yet broadly used for reasons of uncertainity

INTRODUCTIONTO EARLY WARNING

ELLS SUMMER SCHOOL ON

WATER DISASTER PREVENTIONwith emphasis on floods and droughts

• Ultimate goal of early warning:

TO SAVE LIVES AND PROPERTY

• Objective of warning process:

TO PROVIDE INFORMATION ON RISK

• Effective early warning includes:

IDENTIFYING THE HAZARD AND ASSESSING ITS RISK

• Effective early warning needs:

TO BECOME PART OF A MANAGEMENT INFO SYSTEM FOR DECISION MAKING

THREE SEGMENTS:

• FORECAST AND PREDICTION SEGMENT– Forecast of extreme events

• WARNING SEGMENT– Information of possible impacts on people and

infrastructure– Involves reccommendations

• REACTION SEGMENT– Ensures that information is correctly

understood

INTERNATIONAL SUMMER SCHOOL 2010 (June 20 to 26)

WATER DISASTER PREVENTION(with emphasis on floods and droughts)

•Hydrometeorological forecasts in disaster prevention•Basics in hazards, vulnerability and risk assessment•Drought prediction and evaluation methods•Impact of catchment characteristics and land use on water regime•Early warning systems•Role of civil society in emergency and legislation•Case studies and field trips (Prague flooding system) (Details: www.eu-workshop.czu.cz)

Pillar Activities of the Flood/Drought Centre

Research

Informationnetworking

Training& Capacity

buildingNetwork

Knowledge

Curriculum

ParticipationResults/Outcomes

Data/Information

SUMMARY• to apply theory of hydrological extremes to practical

events• to learn new methods of floods and droughts hazard

assessment• to learn new tools for collecting, processing and

implementing hydrological data• to combine different methods of mitigation and

recovery from flood and drought disasters• to introduce early warning to civil society when water

disasters occur

SUMMARY-continued

At least,one week WDP 2010 Workshop in Prague, the Czech Republic is in English including a half week individual selfstudy in home country.

It is designed for 25 to 30 students (BSc/MSc) in Land and Water or related programmes.

Workshop on Water Disaster Prevention

THANK YOU FOR YOUR ATTENTION