GEOL 1 CHAPTER 9

• WATER SUPPLY - it is a prime necessity in public health, an essential to cleanliness, and a fundamental of almost all modern manufacturing process.
• SUPPLY OF PURE WATER — is one of the engineer's greatest gift to the public and at the same time, their greatest responsibilities.
• TUNNELS, DAMS, CANALS, GROUTING, RESERVOIRS, AND BUILDINGS — most engineered works for water supply projects.
• SOURCES OF WATER SUPPLY — ultimate source of practically all water supplies is the fall of rain.
• GEOLOGICAL CONDITIONS GOVERNWHAT HAPPENS TO RAINFALL WHEN IT REACHES THE GROUND

  — part is evaporated

  —part will run off the surface

  — part will be absorbed by vegetation

  — part will eventually find its way into the suboil
• THE WATER CYCLE

  — EVAPORATION

  — CONDENSATION

  — PRECIPITATION

  — TRANSPIRATION

  — SURFACE RUNOFF
• RELATION OF GEOLOGY TO RUNOFF

  — calculation of rainfall losses is vitally important to all hydrological studies.
• RAINFALL QUALITY — rainfall absorbs gasses and floating solid particles from the air before it reaches the ground.
• RAINWATER — is therefore no means pure. it is often definitely acidic. especially during thunderstorm when bitric acid may be formed.
• ACID RAIN — caused by industrial pollution.
• STAFFORDSHIRE BLUE BRICK and ALUMINOUS CEMENT CONCRETE — are the only normal types of conduit lining that successfully resist the moorland water.
• ORDINARY PORTLAND CEMENT CONCRETE — of varying consistencies is seriously affected.
• HARDNESS, TEMPORARY, AND PERMANENT — is the most widely recognized of impurities.
• HARDNESS — the result of cobtact with rocks containing calcium or magnesium carbonate or magnesium sulfate.
• GEOLOGY — not only influences the quality of natural waters but also non geological impurities.
• PORTABLE WATER — is most simply obtained from the flow of rivers or from freshwater lakes.
• REPLENISHMENT OF GROUNDWATER — all over the world the groundwater supplies are being obtained from springs or pumping.
• UNUSUAL SOURCES OF WATER SUPPLY — have been adopted out of necessity in some parts of the world.
• SOME GEOLOGICALLY SIGNIFICANT SYSTEMS —

  are routinely encountered n the development of public water supply system.
• WATER SUPPLY FROM GROUNDWATER — wells constitute the principal means of obtaining water supplies from underground sources.
• WATER SUPPLY FROM IMPOUNDING RESERVOIRS — when adequate of quantities of public water supplies cannot be directly obtain from river or lake abstraction, an obvious alternative is to utilize a distant source of supply such as the streams found in mountain areas.