Droogte in overvloed Erik Querner m.m.v. Henny van Lanen (WU)
Inhoud • Inleiding
Intermezzo’s: waterbeheer en droogte
• Historische droogte Evrotas, Griekenland
• Monitoring Mendoza, Argentinië
• Droogte voorspellen • Discussie
Inleiding Een droogte is een langere periode van maanden of jaren, waarin een regio een tekort in de watervoorziening heeft. In het algemeen een tekort in neerslag, maar ook sneeuwval in de bergen of rivierafvoer uit de bergen. Vele delen van de wereld komt droogte elk jaar voor, met name als er een lange droge zomer is en daarnaast ook een natte periode. Droogte (natuurlijk) niet verwarren met waterschaarste (een door de mens veroorzaakt tekort)
Consequences of a drought Environmental, agricultural, health, economic and social • Diminished crop growth or yield productions • Dust storms, bush fires • Hunger / due to lack of water for irrigation • Habitat damage, affecting both terrestrial and aquatic wildlife • Reduced electricity production due to insufficient available coolant for power stations, and reduced water flow through hydroelectric dams • Reduce the water quality in streams (reduce dilution of pollutants) • Shortages of water for industrial users
Types of droughts
Human influence
Klimaatclassificatie van KöppenGeiger Classification is based on the concept that native vegetation is the best expression of climate. It combines average annual and monthly temperatures and precipitation, and the seasonality of precipitation.
Droogte indicatoren •
Percentage of Normal Precipitation
actual divided by the normal
•
Standardized Precipitation Index (SPI)
probability index
•
Palmer Drought Severity Index
•
Crop Moisture Index
•
Surface Water Supply Index
calculated by river basin, based on snowpack, stream flow, precipitation, and reservoir storage.
•
Reclamation Drought Index
calculated at the river basin level, incorporating temperature, precipitation, snowpack, stream flow, and reservoir levels as input.
a soil moisture algorithm
Historische droogte • In 1389 stond de Rijn bij Keulen voor de derde keer in tien jaar zo laag dat de paarden midden in de rivier liepen • Zomer 1473 van eind april tot half november nauwelijks regen • 1503: zeker vier maanden lang viel er nauwelijks regen • 1540: Het grote zonnejaar – 7 maanden droog en heet De Rijn stond vrijwel droog. Het midden en westen van Europa hadden een Mediterraan klimaat. In Parijs liepen mensen over de bedding van de Seine zonder natte voeten te krijgen. • De 19e eeuw kende een paar opmerkelijk droge jaren: zo viel in Maastricht in 1857 slechts 356 millimeter en in 1864 werd daar 363 millimeter gemeten.
Amerika, mid/westen: The Dust Bowl The Dirty Thirties was a period of severe dust storms causing major ecological and agricultural damage in America and Canada. The phenomenon was caused by severe drought coupled with decades of extensive farming without care to prevent erosion. The Dust Bowl affected 400,000 km2, mainly in Texas, Oklahoma, and adjacent parts of New Mexico, Colorado, and Kansas.
Dust storms were given names as "Black Blizzards" and "Black Rollers"
High planes Aquifer Its one of the world's largest aquifers, it covers an area of approximately 450,000 km² in eight states of the US. About 27% of the irrigated land in the United States overlies this aquifer system, which yields about 30 percent of the nation's ground water used for irrigation. In addition, the aquifer system provides drinking water to 82 percent of the people who live within the aquifer boundary. Some estimates say it will dry up in about 25 / 50 years.
Dad where is our water gone to Son / I tell you when your grown up
Evrotas basin, Greece Water use in a river basin Irrigation
Agriculture Drainage
Groundwater extractions Rainfed agriculture
Regions prone to droughts – often have a high water use Intensive Agriculture – Urban areas - Industries (etc.)
Example case study
MIRAGE
Mediterranean Intermittent River ManAGEment
Case study sites
Ecological Status
Basic Research
Aquatic communities structure Sediment & surface water quality Aquatic & terrestrial linkages Functional attributes (nutrient retention, organic matter processing, sediment transport)
Develoment of measures and support of RBMP Specifications for WFD application in dry streams
Supporting the WFD Implementation for temporary streams
Sustainable use of the water
Hydrological Status
Stream temporality Sensitivity to climate change Runoff generation Flood risk
resources in Mediterranean river basins for agriculture, drinking water and industries
What is sustainable limit to the irrigation in a river basin
Temporary
Rivers are part of the Prat, year dry 2009
Linking hydrology to ecology
Evrotas River basin, Greece Catchment:
2420 km2
Elevation:
0 / 2400 m
Precipitation:
870 mm
Evapotranspiration: 811 mm
Geology: Karst and sediments
Characteristics of the Evrotas basin Population:
63.000
Natural vegetation: 61% Agricultural areas:
38%
Urban areas:
1%
Point Pollution Land uses
Untreated domestic waste water Olive oil mills, orange juice factories Diffuse Pollution of nutrients and pesticides
Hydrological pressures Irrigation: Surface water abstraction for irrigation Ground water abstractions (3.500 wells Drinking water and industrial use Groundwater abstractions
Surface water used for irrigation
Discharge m3/s
Decline in river flow
Spring
Summer
Autumn
Water balance study using SIMGRO model
Example scenarios 1900: only surface water used for irrigation (agric. 25%) 1960: surf water and shallow groundwater (agric. 25%) 1980: surf water and deep groundwater (agric. 30%) Present: agricultural land 38% (olives irrigated) Present
Discharges at Vrontamas - Evrotas
1980 1960
30
1900
Discharge (m3/s)
Measurements
20
10
0 02/01/05
02/07/05
02/01/06
02/07/06
02/01/07
02/07/07
02/01/08
Flow characterization Dry; pools; low flows; flowing Visualize changes for different irrigation intensities Determine what is acceptable/sustainable from an ecological point of view It then defines the max water use for irrigation
Preliminary conclusion: for a sustainable situation at river basin level, the water use for agriculture needs (definitely) to be reduced
Recent droughts
Droughts largest impact of all natural disasters (climatic and geological)
China
Feb – Mar 2010
Russia
Jun – Jul 2010
De Rijn
Mei 2011
Rijn: 10 mei 2011 / 954 m3/s
Rijn bij laag water
Mendoza, Argentinie
Mendoza province has more than 20% of the irrigated land in Argentina
Irrigation water is allocated according to area with water rights
Problems / water shortage (dry years) / suppl. groundwater use / over irrigation (wet years) / high water tables / soil salinization / crop productivity reduction / environmental degradation
MENDOZA RIVER BASIN Andes
Saline soils
Potrerillos dam
Mendoza city
Mendoza irrigated system
Mendoza river
Diversion dam in Mendoza River
Before and after construction of dam
Irrigation canals
Crops: grapes; fruit trees; olives, vegetables
Used to grow good quality wines
Recente ontwikkelingen Als er geen oppervlaktewater beschikbaar is, dan maar grondwater gebruiken, zoals deze Nederlandse wijnboer
en deze Nederlandse aardappelboer
Grondwaterstandsdaling door 7 pompen (ca. 5 mln m3 – beregening nov/maart)
30 m
Water resources are used for 100% or even more
Droogte in Overvloed Monitoring
European Drought Observatory
European Drought Observatory Evolution of the 3/month Standardized Precipitation Index (SPI/3) over western Europe from Jan/April 2011. Values below /1.5 indicate a severe meteorological drought.
Africa La Nina threatens 2 million Ethiopians with drought Thu Apr 28, 2011
ADDIS ABABA / More than two million Ethiopians are in need of food aid due to drought caused by one of the worst La Nina weather phenomenon in a decade, the United Nations said. La Nina, which was blamed for Australia's floods this year, is an abnormal cooling of waters in the Pacific Ocean that wreaks havoc with weather patterns across the Asia/Pacific region, and has brought poor rains to the Horn of Africa.
Droogte in Overvloed Voorspellingen
Trend in droughts
Palmer Drought Severity Index for 1900 to 2002 Cumulative deficit in precipitation and evapotranspiration
20802099
IPCC – 100 years ahead
Expected droughts in Europe Change in the recurrence of 100/year droughts, based on comparisons between climate and water use in 1961 to 1990 and simulations for the 2070s (based on the ECHAM4 and HadCM3 GCMs, the IS92a emissions scenario and a business/as/usual water/ use scenario).
(Lehner et al., 2005)
Discussie • Droogte is een sluimerend proces • Door toenemende bevolking en ontwikkelingen in de landbouw komt droogte steeds vaker en heviger voor • Er is een noodzaak om water besparende maatregelen en technieken in de landbouw toe te passen • Grondwater wordt algemeen gezien als een oneindige bron, maar in veel gebieden wordt nu ingeteerd op de reserves • Noodzaak tot risico spreiding • Meer water vasthouden om droge perioden te overbruggen
Risico spreiding
very innovative high production unit (similar to a Greenhouse)
higher production and drought resistant fields Multiple use wetland
traditional extensive fields
Thank you
