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:
1. TYPE OF SURFACE
2. HOW MUCH IT RAINS
3. 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/enviro
nment/freshwater/change-the-course/waterfootprint-calculator/
TO CALCULATE YOUR WATER FOOTPRINT.