THE WATER CYCLE AND HUMAN USE

97.4% OF ALL WATER ON EARTH IS SALT. 2.6% IS FRESH. 1.984% IS FROZEN (ICE CAPS OR GLACIERS) 0.592% IS GROUND WATER 0.014% IS RIVERS, LAKES, WATER VAPOR REMEMBER, 70% OF EARTH’S SURFACE IS COVERED WITH WATER – MOST OF IT SALT.

SUPPLIES OF WATER EXIST IN DIFFERENT PARTS OF THE WORLD AS SURFACE WATER AND GROUND WATER. THESE SUPPLIES ARE BASED ON CLIMATE AND NATURAL GEOGRAPHY. THESE SUPPLIES CAN CHANGE BASED ON CHANGES IN CLIMATE AND HUMAN INTERVENTION. FOR EXAMPLE, DURING THE LAST ICE AGE MUCH OF AFRICA WAS UNDER A DROUGHT. AREAS THAT WERE RAINFOREST BECAME SAVANAH.

IN TURN, HUMAN INTERVENTION CAN CHANGE WATER AVAILABILITY. HUMANS HAVE HARVESTED SO MUCH FIREWOOD IN SUB SAHARAN AFRICA THAT THE DESERT HAS REPLACED MUCH OF WHAT WAS ONCE GRASSLAND. DEFORESTATION IS OCCURING IN THE AMAZON BASIN. 50% OF THE MOISTURE IN THIS AREA COMES FROM TRANSPIRATION OF MOISTURE FROM TREES. DEFORESTATION COULD RESULT IN THE AMAZON BECOMING GRASSLAND IN A SHORT PERIOD OF TIME.

IN MANY AREAS OF THE WORLD, WATER IS BEING PUPMPED OUT OF AQUIFERS FASTER THAN IT CAN BE REPLINISHED BY RAINFALL AND INFILTRATION. THIS CAN QUICKLY RESULT IN WATER NOT BEING AVAILABLE FOR ANY HUMAN USE IN THOSE AREAS. ANOTHER EXAMPLE IS THE ARAL SEA. SO MUCH WATER IS TAKEN FROM RIVERS FEEDING THE ARAL SEA THAT THE VOLUME HAS DRASTICALLY BEEN REDUCED. THE OLD SEA BED IS DESERT, AND THE LAND AROUND THE ARAL IS BECOMING COOLER AND DRYER (MICRO CLIMATE CHANGE) DUE TO LOSS OF WATER.

GROUNDWATER: THE WATER HELD IN THE PORES OF SOIL AND ROCK. WHEN IT RAINS, PART OF THE RAIN BECOMES GROUNDWATER AND PART RUNS OFF. HOW MUCH RUNS OFF IS DETERMINED BY: TYPE OF SURFACE HOW MUCH IT RAINS SLOPE OF THE LAND

ANOTHER SITUATION SOMETIMES OCCURS WHEN IT HAS BEEN RAINING FOR SEVERAL DAYS AND THE SOIL BECOMES SATURATED. IF IT IS SATURATED, NO MORE RAIN CAN SOAK INTO THE GROUND, SO IT ALL HAS TO RUN OFF. WHEN THIS SITUATION DEVELOPS, THERE IS DANGER OF FLASH FLOODS. THIS HAPPENED SEVERAL TIMES DURING THE PAST SUMMER IN SOME OF NORTH CAROLINA’S WESTERN COUNTIES.

WHAT FACTORS DOES THE STATE OF NORTH CAROLINA USE TO DETERMINE THE QUALITY OF SURFACE WATERS? SEDIMENT FECAL COLIFORM BACTERIA NUTRIENTS OXYGEN TOXIC SUBSTANCES pH

WATER QUALITY IS IMPORTANT FOR DRINKING WATER SUPPLY, AS A HABITAT FOR AQUATIC ORGANISMS, AND FOR WILDLIFE THAT USE THE STREAMS. STREAM QUALITY IS A PROBLEM IN BOTH THE U.S. AND IN NORTH CAROLINA BECAUSE OF: - URBAN SPRAWL - RAPID POPULATION GROWTH - AGRICULTURE

POLLUTION SOURCES INCLUDE: URBAN STORMWATER RUNOFF INEFFICIENT WASTEWATER TREATMENT PLANTS AGRICULTURAL WASTES EFFLUENT FROM CHEMICAL PLANTS DUMPING INTO STREAMS DESTRUCTION OF VEGETATION BUFFERS BORDERING STREAMS

SURFACE WATER IS IMPORTANT BECAUSE SUCH A SMALL PERCENT OF OUR WATER EXISTS AS SURFACE WATER. WE CONTINUALLY DISTURB THE FRESH WATER ECOSYSTEMS WE HAVE: ALTER FOR TRANSPORTATION DIVERT FOR AGRICULTURE AND MUNICIPAL NEEDS DAM FOR ENERGY USE FOR INDUSTRIAL COOLANT STRAIGHTEN FOR CONVENIENCE

NORTH CAROLINA IS BLESSED WITH PLENTY OF SURFACE WATER. SOUTHWESTERN NC AVERAGES 90 INCHES OF RAIN PER YEAR. NC EAST OF THE MOUNTAINS AVERAGES 40 TO 50 INCHES OF RAIN PER YEAR. THE DRIEST PART OF NC IS THE VALLEY OF THE FRENCH BROAD RIVER, WHICH AVERAGES 37 INCHES PER YEAR.

NORTH CAROLINA IS NOT WITHOUT ITS WATER PROBLEMS. GREENSBORO IS IN THE UPPER PART OF THE CAPE FEAR RIVER BASIN, AND THE STREAMS ARE NOT LARGE ENOUGH TO PROVIDE ITS GROWING POPULATION WITH WATER DURING A DROUGHT. AGRICULTURAL RUNOFF IN THE LOWER CAPE FEAR RIVER BASIN IS A PROBLEM. THE NEUSE RIVER BASIN IS VERY HEAVILY POPULATED, AND URBAN RUNOFF FROM RALEIGH AND DURHAM IS A PROBLEM. A SIMILAR PROBLEM EXISTS IN THE LOWER CATAWBA RIVER BASIN BECAUSE OF CHARLOTTE.

MAJOR WATER PROBLEMS IN NORTH CAROLINA STORMWATER RUNOFF DROUGHT AGRICULTURAL POLLUTION AQUIFER DEPLETION AND SALT WATER INTRUSION

GO TO: http://environment.nationalgeographic.com/environment/freshwater/change-the-course/water-footprint-calculator/ TO CALCULATE YOUR WATER FOOTPRINT.