GROUNDWATER Flashcards
- IT IS THE LARGEST RESERVOIR OF FRESH WATER AVAILABLE TO HUMAN
GROUNDWATER
IMPORTANCE OF GROUNDWATER
- INVALUABLE SOURCE OF FRESH WATER FOR THE FFG:
INDUSTRY
AGRICULTURE
HUMAN WELL-BEING - IMPORTANT EROSIONAL AGENT- RESPONSIBLE FOR
FORMATION OF SINKHOLES AND DOLINE. - ACTS AS STORAGE OF METEORIC WATER DURING PRECIPITATION
DISTRIBUTION OF GROUND WATER
DIFFERENT ZONES
DIFFERENT ZONES
- ZONE OF SOIL MOISTURE- UPPERMOST LAYER OF
SOIL WITH MOISTURE FROM METEORIC WATER. - VADOSE ZONE (UNSATURATED ZONE)
3 PHREATIC ZONE (SATURATED ZONE
- IT IS THE UPPER LIMIT OF THE ZONE OF SATURATION
(PHREATIC ZONE). - ITS CONFIGURATION DEPENDS FROM SEASON TO
SEASON, AND ON THE AMOUNT OF PRECIPITATION
THE AREA RECEIVES. - ITS SUBRSURFACE SHAPE IS A SUBDUED REPLICA OF
THE SURFACE TOPOGRAPHY
THE WATER TABLE
FOR THIS TO OCCUR, THE ELEVATION OF THE
WATER TABLE MUST BE HIGHER THAN THE LEVEL OF THE SURFACE OF
THE STREAM.
GAINING STREAM
WHEN THIS HAPPENS, THE
ELEVATION OF THE WATER TABLE MUST BE LOWER THAN THE
SURFACE OF THE STREAM. CONNECTED TO THE GROUNDWATER
SYSTEM BY A CONTINUOUS SATURATED ZONE
LOSING STREAM (CONNECTED)
THEY CAN BE DISCONNECTED
FROM THE GROUNDWATER SYSTEM BY AN UNSATURATED ZONE.
LOSING STREAM (DISCONNECTED)
- IT IS THE UPPER LIMIT OF THE SATURATION ZONE
- DEPTH OF IT IS HIGHLY VARIABLE IN NATURE
THE WATER TABLE
FACTORS AFFECTING GROUND WATER MOVEMENT AND STORAG
- POROSITY
- PERMEABILITY
THE ABILITY OF A ROCK OF SEDIMENT TO HOLD AND
RETAIN WATER
POROSITY
REFERS TO THE ABILITY TO TRANSMIT FLUIDS.
PERMEABILITY
AN IMPERMEABLE LAYER THAT PREVENTS WATER MOVEMENT.
AQUITARDS
AN PERMEABLE ROCK STRATA OR SEDIMENT THAT CAN FREELY
TRANSMIT WATER.
AQUIFER
GROUND WATER MOVEMENT
- RECHARGE ZONE / AREA
- DISCHARGE ZONE / AREA
- DRAINAGE DIVIDE
GROUNDWATER EXTRACTION
COMMON METHOD FOR GW EXTRACTION IS THRU WELLS
DRAWDOWN -
CONE OF DEPRESSION -
- TERM USED TO DESCRIBE THE LOWERING OF THE WATER
TABLE SURROUNDING THE WELL WHENEVER WATER IS BEING EXTRACTED
FROM IT
DRAWDOWN
A CONICAL DEPRESSION IN THE WATER TABLE
CREATED BY DRAWING THE WATER OUT OF THE WELL.
CONE OF DEPRESSION
OCCURS WHEN THE WATER
TABLE INTERSECTS EARTH’S SURFACE
CAUSING A NATURAL OUTFLOW OF
GROUNDWATER
SPRING
WHEN GROUND WATER
BECOMES HEATED, AND EMERGES TO THE
SURFACE AS A NATURAL OUTFLOW WITH
A MUCH HIGHER TEMPERATURE THAN THE
MEAN AIR TEMP
HOT SPRINGS
ARE INTERMITTENT HOT SPRINGS
OR FOUNTAINS IN WHICH COLUMNS OF
WATER ARE EJECTED WITH GREAT FORCE
AT VARIOUS INTERVALS, OFTEN RISING 30
TO 60 METERS (100 TO 200 FEET) INTO
THE AIR
GEYSERS
forms where an aquitard is situated above the main water
table.
Perched water table
any situation in which groundwater
under pressure rises above the level of the aquifer.
Artesian Systems
- at this location, the pressure
surface is below ground level
Nonflowing artesian well
when the pressure surface is
above the ground and a well is drilled into the aquifer.
Flowing artesian well
like many of our other valuable natural resources,
groundwater is being exploited at an increasing rate. In some areas, overuse
threatens the groundwater supply. In other places, groundwater withdrawal has
caused the ground and everything resting on it to sink. Still other localities are
concerned with the possible contamination of the groundwater supply.
Environmental Problem
groundwater dissolves rock. This fact is key to
understanding how caverns and sinkholes form. Because soluble rocks, especially
limestone, underlie millions of square kilometers of Earth’s surface, it is here that
the groundwater carries on its important role as an erosional agent. Limestone is
nearly insoluble in pure water but is quite easily dissolved by water containing small
quantities of carbonic acid, and most groundwater contains this acid. It forms
because rainwater readily dissolves carbon dioxide from the air and from decaying
plants. Therefore, when groundwater comes in contact with limestone, the
carbonic acid reacts with the calcite (calcium carbonate) in the rocks to form
calcium bicarbonate, a soluble material that is then carried away in solution.
Geologic Work of Groundwater
