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 km336 % Slovakia km334 % Prešov, SK (City center) mil. m372 % Plot of land 6300,5 mil. m337 % Residential house m376 % WATER BALANCE OF THE INVESTIGATED TERRITORY

RUNOFF FROM URBAN AND FOREST ENVIRONMENTS Decrease of runoff is overlooked flood prevention measure

SOIL SEALING DESTROYS SMALL WATER CYCLE(S) ON LAND

EARTH – WATER BUDGET Oceans Atmosphere Land Evaporation km³/year Precipitation km³/year Runoff km³/year Precipitation km³/year Evaporation 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“

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

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

Old water paradigm soil sealing has minimal influence on global warming New water paradigm soil sealing may be important factor in global warming

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)

GRACIAS! THANKS! MERCI! DANKE! ĎAKUJEM!