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Water for the Recovery of the Climate -
A New Water Paradigm
Michal Kravcik, Juraj Kohutiar NGO „People and Water“
Slovakia
Water Tribune, Zaragoza, 23rd August 2008
TOPICS OF THIS PRESENTATION
INTRODUCTION
BODY
• Human impact on water cycle
• Water cycle and climate change
• Recovery of the climate
CONCLUSION
HUMAN IMPACT
ON WATER CYCLE
“On July 22d [1494], he [Columbus] departed for Jamaica…. every afternoon there was a rain squall that lasted for about an hour. The admiral attributes this to the great forests of that land; he knew from experience that formerly this also occurred in the Canary, Madeira, and Azore Islands, but since the removal of forests that once covered those islands they do not have so much mist and rain as before.”
/Christopher Columbus’ biography
by his son Ferdinand/
FRESHWATER STOCKS ON EARTH
DEFORESTATION & AGRICULTURE
Deforestation / some forms of farming cause:
• increase of runoff (and erosion)
• lower infiltration (groundwater recharge)
• lower evaporation (change of regional climate)
• natural meanders removed
• adjacent swamps drained
• shortening length increases slope
• acceleration of runoff • lowering land's ability
to retain water
ALTERATION OF RIVERS
SOIL SEALING IN CITIES
• about 20 billion m3 of rainwater sluiced from municipalities of Europe annually
PAVEMENT IMPACT
• infiltration decreases (groundwater recharge decreases)
• evaporation decreases (air humidity decreases)
• runoff increases (through sewage to rivers and sea)
Free surface
Paved surface
Precipitation
(mm/ year)
Volume of water circulating
Runoff (indicator of soil sealing)
Europe 750 7 790 km3 36 %
Slovakia 762 37 km3 34 %
Prešov, SK (City center)
628 12 mil. m3 72 %
Plot of land 630 0,5 mil. m3 37 %
Residential house
630 766 m3 76 %
WATER BALANCE OF THE INVESTIGATED TERRITORY
RUNOFF FROM URBANAND FOREST ENVIRONMENTS
Decrease of runoff is overlooked flood prevention measure
SOIL SEALING DESTROYSSMALL WATER CYCLE(S) ON LAND
EARTH – WATER BUDGET
Oceans
Atmosphere
Land Evaporation361 000 km³/year
Precipitation324 000
km³/year
Runoff37 000
km³/year
Precipitation99 000
km³/yearEvaporation
62 000
km³/year
There is more water in „small“ water cycle than in „large“ water cycle!!!
WATER CYCLE
AND
CLIMATE CHANGE
The rain in Spain falls
mainly on the plain... (???)
The rain in Slovakia fails mainly on the plain...
HOT CLIMATIC UMBRELLA OF A CITY
Soil sealing resulting in the lack of evapotranspiration in urban areas is the main reason of “urban heat island” effects.
Why the rain fails mainly on the plain?
Rising air flows push precipitation away to colder and more humid areas
PRECIPITATION TRENDS IN CITY PRESOV
PRECIPITATION TRENDS IN SLOVAKIA
PRECIPITATION IN MOUNTAINS AND
LOWLANDS – DANUBE WATERSHED
RECOVERY
OF THE CLIMATE
When fire and water are at war,
it is the fire that loses.
/Spanish Proverb/
GROWTH OF EXTREME WEATHER WITH
DECLINE OF SMALL WATER CYCLE
The less water “soil sealing” allows in small water cycle, the more frequent and more severe are extremes of weather
DESTRUCTION AND RENEWAL OF SMALL WATER CYCLE
There is a hope of recovery by returning the lost water back to the land.
RAINWATER HARVESTING FROM ROOFS IN CITIES
WATER CYCLE OF A FAMILY HOUSE
RAINWATER HARVESTING ON SLOPES
RAINWATER HARVESTING EXAMPLES
INFRARED PICTURE OF THE „WATER FOREST“
Li1
20.0
33.0 °C
22
24
26
28
30
32
FLI R Syst ems
°C
2021222324252627282930313233
Label Cursor Min Max
Li1 - 19.7 35.9
SUMMARY
Take care, your worship,
those things over there
are not giants
but windmills...
Miguel de Cervantes, Don Quijote
Old water paradigm
• protects surface water as the main source and reserve of water
New water paradigm
• protects groundwater and soil water as the main treasure of water
www.waterparadigm.org
Old water paradigm
• soil sealing has minimal impact on the water cycle
New water paradigm
• soil sealing has a fundamental impact on the water cycle
www.waterparadigm.org
Old water paradigm
• soil sealing has minimal influence on global warming
New water paradigm
• soil sealing may be important factor in global warming
www.waterparadigm.org
Old water paradigm
• rainwater is an inconvenience, needs to be quickly removed
New water paradigm
• rainwater is an asset that needs to be retained (especially in soil/plants)
www.waterparadigm.org
GRACIAS! THANKS!MERCI! DANKE!
ĎAKUJEM!... ... ...