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2. WATER DISASTER PREVENTION (40 min.). WATER DISASTER PREVENTION focused on floods and droughts INFORMATION LECTURE SUMMER SCHOOL/WORKSHOP Prof. Pavel.

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Presentation on theme: "2. WATER DISASTER PREVENTION (40 min.). WATER DISASTER PREVENTION focused on floods and droughts INFORMATION LECTURE SUMMER SCHOOL/WORKSHOP Prof. Pavel."— Presentation transcript:

1 2. WATER DISASTER PREVENTION (40 min.)

2 WATER DISASTER PREVENTION focused on floods and droughts INFORMATION LECTURE SUMMER SCHOOL/WORKSHOP Prof. Pavel KOVAR CULS Prague

3 WATER RESOURCES MANAGEMENT PROTECTION OF WATER RESOURCES PROTECTION OF SOCIETY AGAINST WATER EXTREMES INTEGRATED WATER RESOURCES MANAGEMENT: DUBLINS PRINCIPES (1992): FRESH WATER IS AN EXHAUSTIBLE AND VULNERABLE FRESH WATER IS AN EXHAUSTIBLE AND VULNERABLE RESOURCES RESOURCES PARTICIPATION OF ALL PARTICIPATION OF ALL WATER AS AN ASSET WATER AS AN ASSET IMPORTANT ROLE OF WOMEN IMPORTANT ROLE OF WOMEN WATER REQUIREMENTS AVAILABLE RESOURCES

4 STATUS OF WORLD FRESH WATER AVAILABILITY PARAMETR STATUS POPULATION* (in billions) POPULATION AFFECTED BY WATER SCARCITY (in millions) COUNTRIES AFFECTED BY WATER SCARCITY * Medium population projection Source: Gardner and Engelman, 1997 Note: Some other sources may have have a different view

5 Floods & Droughts killed 450 thousands people affected 1,5 bilions people

6 Floods & Droughts 80% of all catastrophes Damage of 370 bilions USD

7 REASONS 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?

8 HOW TO LIVE WITH FLOODS CASE STUDY: Czech Republic, August 2002

9 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: Q max =5 300 m 3.s -1 (Q 500 ), 15 people killed, 4 billions EUR

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13 REAL FLOODS (rainfall, surface runoff) Trója - Císařský ostrov - ÚČOV

14 Preparations of flood protection measures Flood prevention Flood effectiveness

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18 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

19 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.)

20 BASIC ISSUES FOR EFFECTIVE FLOOD CONTROL To increase natural water retention capacity Interrupting surface runoff, decrease water velocity, linking river channel with flood plain (inundation) To build technical measures Poldering and diking, mobile gates in urbanised areas, dams and reservoirs. To develop flood prevention system Flood zoning (land planning and management), Role of government, civil service, municipality, owners. Early warning system.

21 HOW TO MITIGATE FLOOD IMPACTS (High impact public issues) FLOOD PREVENTION STRATEGY Structural 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

22 MANAGEMENT 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)

23 strip croppingstrip cropping Agronomic erosion control

24 terracesterraces TECHNICAL EROSION CONTROL

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26 Gully/torrent controlGully/torrent control

27 DEFINITIONS OF DROUGHTS CLIMATE VARIATIONS PRECIPITATION DEFICITHIGH TEMPERATURES INFILTRATION DECREASEEVAPORATION INCREASE SOIL MOISTURE DEFICIT PLANT STRESS GROUNDWATER STORAGE DECREASE RUNOFF DECREASE ECONOMIC, SOCIAL AND ENVIRONMENTAL CONSEQUENCES Meteorologic drought Agricultural drought Hydrologic drought

28 Trends in soil moisture content (  AW) during rainless periods Drought analysis – Depletion curves

29 DROUGHT ASSESSMENT METHODS Return period of drought (Q 364, Q 355 ) 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)

30 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 (CO 2, N 2 O, CH 4, 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

31 CLIMATE CHANGE EURURALIS Scenarios Since 1800 CO 2 concentrations increased by 30%, CH 4 by 150%, N 2 O by 20%. Prognosis to 2100 global temperature increase by 1,9°C to 4,3°C depending 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 regulation High Regulation

32 POSSIBLE IMPACTS OF CLIMATE CHANGE IN WATER RESOURCES TEMPERATURE INCREASE PRECIPITATION VARIABILITY DECREASE INCREASE 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 SILTATION IN RESERVOIRS DECREASE OF MANAGABLE WATER RESOURCES DECREASE OF RE- SERVOIR LIFE TIME AND INCREASE OF MAINTENANCE COST

33 RISK ASSESSMENT Risk = 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

34 INTRODUCTION TO EARLY WARNING ELLS SUMMER SCHOOL ON WATER DISASTER PREVENTION with emphasis on floods and droughts

35 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

36 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

37 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:

38 Pillar Activities of the Flood/Drought Centre Research Information networking Training & Capacity building Network Knowledge Curriculum Participation Results/ Outcomes Data/ Information

39 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

40 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.

41 Workshop on Water Disaster Prevention

42 THANK YOU FOR YOUR ATTENTION


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