1. Chapter 13 – Water Resources

2. WATER THREE QUARTERS OF OUR PLANET IS COVERED BY WATER, BUT LESS THAN 3% OF THE WATER ON EARTH IS FRESH WATER THAT IS WATER USABLE FOR DOMESTIC, AGRICULTURAL AND INDUSTRIAL PURPOSES.

4. WATER IS CRUCIAL FOR MODERN INDUSTRY AND SOCIETY AS WELL AS EACH INDIVIDUAL: WATER IS USED IN TRANSPORTATION, POWER GENERATION, FOOD PRODUCTION AND PROCESSING, MANUFACTURING AND WASTE DISPOSAL.

5. OUR BODIES ARE ALSO COMPOSED MAINLY OF WATER ABOUT 70% OF OUR BODY BY WEIGHT IS WATER. AND WATER IS THE MEDIUM IN WHICH ALL BIOCHEMICAL REACTIONS OCCUR OR WHERE THE CHEMISTRY OF LIFE TAKES PLACE.

6. OUR CONCERNS ABOUT WATER INCLUDE BOTH ITS QUALITY AND ITS QUANTITY.

7. FROM PRIMITIVE TIMES UNTIL THE PRESENT, WATER HAS BEEN ABSOLUTELY ESSENTIAL TO CIVILIZATION

8. OUR NEED FOR WATER HAS INCREASED 1000 FOLD AND, MOST OF THAT INCREASE HAS OCCURRED DURING THE LAST HUNDRED YEARS.

9. THE HUMAN BODY ONLY REQUIRES 2 LITER (2 QUARTS) OF WATER A DAY TO PREVENT FATAL DEHYDRATION.

11. 5,500 5,000 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 190019201940196019802000 Water use (cubic kilometers per year) Total use Agricultural use Industrial use Domestic use Year

12. WATER: WATER OCCURS IN SOLID, LIQUID AND VAPOR FORMS AND IT IS DISTRIBUTED AMONG OCEANIC, ATMOSPHERIC, AND TERRESTRIAL RESERVOIRS.

13. THE WATER OR HYDROLOGIC CYCLE IS MOVEMENT OF WATER AMONG OCEANIC, ATMOSPHERIC AND TERRESTRIAL RESERVOIRS.

15. EVAPORATION: THE PROCESS BY WHICH WATER CHANGES FROM A LIQUID TO A VAPOR, AT TEMPERATURE THAT IS BELOW THE BOILING POINT OF WATER. TRANSPIRATION: THE LOSS OF WATER VAPOR FROM PLANTS. SUBLIMATION: THE PROCESS BY WHICH WATER CHANGES DIRECTLY FROM A SOLID TO A VAPOR WITH PASSING THROUGH AN INTERVENING LIQUID PHASE.

16. CONDENSATION: THE PROCESS BY WHICH WATER CHANGES FROM A VAPOR TO A LIQUID. DEPOSITION: THE PROCESS BY WHICH WATER CHANGES DIRECTLY FROM A VAPOR INTO A SOLID (ICE CRYSTALS). PRECIPITATION: THAT PORTION OF THE ATMOSPHERIC WATER THAT RETURNS FROM CLOUDS TO THE EARTH'S SURFACE IN THE FORM OF RAIN, SNOW, ICE PELLETS, AND HAIL.

17. THE EVAPORATION CONDENSATION AND SUBLIMATION DEPOSITION SEQUENCES PURIFY WATER.

18. WHEN WATER IS VAPORIZES, THE SUSPENDED AND SOLUBLE SUBSTANCE, SUCH AS SEA SALTS AND MICROORGANISM ARE LEFT BEHIND. THUS THE CONDENSATE, WHICH IS ALMOST ENTIRELY FREE OF THOSE SUBSTANCE, FORMS FRESHWATER PRECIPITATION.

19. GROUND WATER MORE THAN 97 PERCENT OF THE UNFROZEN RESOURCES OF FRESH WATER IN THE UNITED STATES IS CONTAINED IN UNDERGROUND RESERVOIRS. GROUNDWATER THAT LIES WITHIN 3300 FEET OF THE EARTH'S SURFACE IS CONSIDERED TO BE ECONOMICALLY RECOVERABLE.

20. ITS VOLUME IS MORE THAN 9X THAT OF THE GREAT LAKES. !!! AT PRESENT, ABOUT 50% OF THE UNITED STATES POPULATION OBTAIN ITS WATER SUPPLY FROM GROUNDWATER SOURCES.

21. NOT ALL THE PRECIPITATION THAT REACHES THE EARTH'S SURFACE, HOWEVER FINDS ITS WAY INTO UNDERGROUND RESERVOIRS. A PORTION OF THE PRECIPITATION EVAPORATES, WHILE THE REMAINDER RUNS OFF INTO STREAMS OR RIVERS. PRECIPITATION THAT DOES REACH THE EARTH'S SURFACE AND THAT SEEPS INTO THE GROUND IS CALLED INFILTRATION.

23. INFILTRATION IS DEPENDED ON : 1.TOTAL AMOUNT OF PRECIPITATION, 2.TOPOGRAPHY. 3.THE CLIMATE AND 4.PHYSICAL PROPERTIES OF THE SOIL.

24. INFILTRATING WATER TYPICALLY ACCUMULATES IN TWO ZONES WITHIN THE UPPER SOIL AND ROCK LAYERS OF THE EARTH'S CRUST.

25. IN THE UPPERMOST BAND, THE ZONE OF AERATION, PORES SPACES CONTAIN BOTH WATER DROPLETS AND AIR.

26. WATER IN THIS ZONE IS USED BY LAND PLANTS AND IS EVENTUALLY LOST TO THE ATMOSPHERE BY EVAPORATION AND TRANSPIRATION.

27. UNDER THE INFLUENCE OF GRAVITY, MOISTURE THAT REMAINS IN THE SOIL IS GRADUALLY DRAWN DOWN AND ACCUMULATES IN A ZONE OF SATURATION.

28. PORE SPACES AND FRACTURES IN THE ROCKS AND SOIL IN THE ZONE OF SATURATION FILL OR SATURATE COMPLETELY WITH WATER. THIS ZONE OF SATURATION CONSTITUTES THE GROUNDWATER RESERVOIR.

29. THE SURFACE THAT SEPARATES THE GROUNDWATER RESERVOIR AND THE UPPER ZONE OF AERATION IS CALLED THE WATER TABLE.

31. LAYERS OF THE GROUNDWATER RESERVOIR THAT HIGH PERMEABILITY AND TRANSMIT WATER ARE CALLED AQUIFERS.

32. LAYERS OF SAND AND GRAVEL ARE GOOD AQUIFERS, WHEREAS CLAY AND MOST CRYSTALLINE ROCKS, SUCH AS GRANITE, THAT HAVE LOW PERMEABILITY ARE POOR AQUIFERS.

34. GROUNDWATER FLOWS NATURALLY THROUGH THE PERMEABLE LAYERS TOWARDS VARIOUS POINTS OF DISCHARGE SUCH AS RIVER LAKE, AND SEAS.

35. THE MOVEMENT OF GROUNDWATER IS EXTREMELY SLOW. A SPEED OF 50 FEET PER YEAR IS TYPICAL, BUT THE SPEED CAN VARY WIDELY FROM ON LOCATION TO ANOTHER.

36. POLLUTIONS AND GROUNDWATER GROUNDWATER MOVES VERY SLOWLY, AND THIS SLOW, SMOOTH MOVEMENT MIXING AND DILUTION OF POLLUTANTS IS SEVERELY LIMITED ONCE THEY ARE INTRODUCED INTO A GROUNDWATER RESERVOIR.

37. GROUNDWATER DEPLETION

38. TODAY WE ARE DEPLETING GROUND WATER A RATE THAT EXCEEDS THE RATE OF NATURAL RECHARGE. SUCH A SITUATION NOW PREVAILS IN THE HIGH PLAINS REGION OF WESTERN, WHICH ARE IRRIGATED BY WATER THAT IS PUMPED FROM THE GROUND.

39. BECAUSE EVAPORTRASPIRATION RATES ARE HIGH AND PRECIPITATION RATES ARE LOW IN THIS AREA, LITTLE SURFACE WATER IS AVAILABLE FOR GROUNDWATER RECHARGE. AS A RESULTS WITHDRAWAL IS OCCURRING 50 TIMES FASTER THAN NATURAL RECHARGE.

40. WYOMINGSOUTH DAKOTA NEBRASKA COLORADO KANSAS OKLAHOMA NEW MEXICO TEXAS 0100 Miles Kilometers Less than 61 meters (200 ft) 61-183 meters (200-600 ft) More than 183 meters (600 ft) (as much as 370 meters or 1,200 ft. in places) 0160 EBBING OF THE OGALLALA

41. Groundwater Overdrafts: High Moderate Minor or none

42. Acute shortage Shortage Adequate supply Metropolitan regions with population greater than 1 million

43. Withdrawing Groundwater AdvantagesDisadvantages Good source of water for drinking and irrigation Available year- round Exists almost everywhere Renewable if not overpumped or contaminated No evaporation losses Cheaper to extract than most surface waters Aquifer depletion from overpumping Sinking of land (subsidence) when water removed Polluted aquifers unusable for decades or centuries Saltwater intrusion into drinking water supplies near coastal areas Reduced water flows into streams, lakes, estuaries, and wetlands Increased cost, energy use, and contamination from deeper wells

44. Groundwater Depletion PreventionControl Waste less water Subsidize water conservation Ban new wells in aquifers near surface waters Buy and retire groundwater withdrawal rights in critical areas Do not grow water- intensive crops in dry areas Reduce birth rates Raise price of water to discourage waste Tax water pumped from wells near surface waters Set and enforce minimum stream flow levels

45. SALT-WATER INTRUSION AND GROUND SUBSIDENCE

46. IN REGIONS WHERE FRESH GROUNDWATER IS LOCATED ADJACENT TO SALTY GROUNDWATER, OVER WITHDRAWAL OF FRESH WATER CAN CAUSE THE SALT WATER TO MIGRATE TOWARDS THE FRESH GROUNDWATER RESERVOIR. THE RESULTS IS THAT FRESH WATER IS REPLACED BY SALT WATER IN THE AQUIFER.

48. SOMETIMES WHEN GROUNDWATER IS REMOVED, THE EARTH MATERIALS THAT CONSTITUTE AQUIFERS BECOME COMPACTED, WHICH CAUSES THE OVERLYING LAND TO SUBSIDE.

50. WETLANDS: MARSHES, SPRINGS, AND SOME STREAMS AND LAKES ARE FORMED WHEN THE WATER TABLE EITHER INTERCEPTS OR IS HIGHER THAN THE LAND SURFACE IN THOSE SITUATIONS, NO UPPER ZONE OF AERATION EXISTS.

51. DURING LONG DRAY SPELLS IN WHICH THE WATER TABLE IS MUCH LOWER THAN A STREAMBED, THE STREAM MAY SUPPLY WATER DIRECTLY TO THE GROUND WATER RESERVOIR.

52. STREAMS AND RIVERS WATER THAT DOES NOT INFILTRATE INTO THE GROUND OR EVAPORATE REMAINS ON THE SURFACE OF THE EARTH (AS SURFACE WATER) AND BECOMES RUNOFF.

53. THE RUNOFF THEN TRAVELS AS STREAMS AND RIVERS WHICH ARE THE MAJOR PATHWAYS TAKEN BY THE RUNOFF COMPONENTS OF THE WATER CYCLE IN ITS JOURNEY FROM THE LAND TO THE SEA.

54. THE LAND AREA THAT DELIVERS THE WATER TO A COMMON POINT IS CALLED A DRAINAGE BASIN OR WATERSHED

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58. LAKES: DEPRESSIONS IN THE LANDSCAPE ALLOW LAKES TO EXIST. THE WATER THAT FILLS THOSE DEPRESSIONS COMES FROM RUNOFF OR GROUNDWATER OR BOTH. SOME LAKES HAVE RIVERS THAT RUN INTO AND OUT OF THEM, SOME HAVE ONLY OUTLETS, OTHERS HAVE ONLY INLETS, AND SOME HAVE NEITHER INLETS NOR OUTLETS. LAKE DEPLETION

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63. OCEANS: THE SEA, BY FAR THE EARTH'S LARGEST RESERVOIR OF WATER, IS THE ULTIMATE RECEPTACLE OF THE TERRESTRIAL WATER, WHETHER IT TRICKLES INTO IT FROM MELTING GLACIAL ICE, SLOWLY SEEPS THROUGH PERMEABLE ROCK AND SOIL, OR RUSHES DOWN THE COURSES OF STREAM CHANNELS.

64. VIEWED FROM SPACE, THE OCEAN IS THE MOST PROMINENT FEATURE OF THE EARTH'S SURFACE. IT COVERS 71 PERCENT OF THE TOTAL AREA, TO AN AVERAGE DEPTH OF 2.5 MILES.

65. SEAWATER CONTAINS LARGE QUANTITIES OF DISSOLVED SALTS, THE MOST ABUNDANT OF WHICH ARE SODIUM CHLORIDE AND MAGNESIUM SULFATE.

66. WORLD WIDE WATER SHORTAGE AREAS

68. WATER USE IN THE UNITED STATES

70. IRRIGATION TECHNIQUES

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