REGIONAL GROUNDWATER FLOW Flashcards
it is the recharge area of water
groundwater basin, watershed or catchment
the movement of water is ______________
3 dimensional
an area in which groundwater is discharged to the land surface, surface water, or atmosphere
groundwater discharge zone
recharge area is usually at topographic________
high places
high topography means the water table is ____
deep
discharge area is usually at topographic________
low
usually topographic high places
deeper water tablo
Recharge-
-topographic lows
- shallow water table
-spring, seep, lake or streams
-vegetation: wet soils
-arid: thicker veg cover or salt deposit
Discharge
true or false: law elevation means low-pressure area which is why it is the discharge area
true
water age of unconfined aquifer
younger
water age of confined aquifer
older
- a line in a 2 dimensional groundwater flow field such that the total hydraulic head is the same everywhere on the surface
Equipotential Line
-connects points or equal head and thus represents the height of the water table/ or Potentiometeric surface of a confined aquifer, above a datum plane
Equipotential lines
-idealized paths followed by particles of water as they move through the aquifer
Flow lines
played a role in the settlement pattern of many lands
- permanent or ephemeral
spots provide simple mechanism of springs
Spring-
Spring
Topographic lows-
-contact with heat source
though to have therapeutic value
Mineralized and thermal springs
forms when water table reaches the surface
depression spring
spring caused by depression
depression spring
spring caused by bedding
contact spring
spring caused by fault
fault spring
spring caused by dissolved limestone or cave system
sinkhole spring or solution spring
spring due to highly jointed material
joint spring
spring caused by fracture
fracture spring
some of the largest springs are found in _________
limestone bedrock
All surface-water features (streams, lakes, reservoirs, wetlands, and estuaries) interact with groundwater.
These interactions take many forms. In many situations, surface-water bodies gain water and solutes from ground-water systems, and in others, the surface-water body is a source of groundwater recharge and causes changes in groundwater quality.
As a result, withdrawal of water from streams can deplete groundwater or conversely, pumpage of groundwater can deplete water in streams, lakes, or wetlands.
Groundwater and Surface-Water Interactions
is concerned with the distribution of earth material as they affect porosity and hydraulic conductivity of the earth.
Hydrogeologist
is a gently sloping plain consisting of alluvium.
It is normally delimited by uplands on either side that rise above the level of the valley to varying heights.
More specifically, the alluvial valley of a given stream is that portion of its alluvial plain upstream from its deltaic plain
Alluvial Valleys
A very real hindrance to ground-water exploration.
A formation may change in lithology from one locality to another accounts for some of the difficulties associated with studies of sedimentary rock units.
Complex Stratigraphy
can create very complex hydrogeologic systems, in which the determination of the locations of recharge and discharge zones and flow systems is confounded.
Not only must the hydrogeologist determine the hydraulic characteristics of rock units and measure ground-water levels in wells to determine flow systems, but detailed geology must also be evaluated.
In most cases, the basic geologic structure will have already been determined; however, logs of test wells and borings must be reconciled with the preexisting geologic knowledge.
Folding and faulting of sedimentary rocks
- based on primary permeability is a function of grain size, shape, and sorting of the original sediments
Hydraulic conductivity (clastic)
t of f: Cementation cannot perform K
Desert areas receive 10 (______) of precipitation or less each year.
Cold deserts, such as Antarctica, can have great accumulations of water. In warm deserts, however, the potential evapotranspiration may be many times the annual precipitation.
Under such conditions, there is often virtually no local ground-water recharge. Yet, some warm deserts can have large volumes of fresh water stored beneath them.
25 cm
They are regional features, bounded on the continental side by highlands and seaward by a coastline.
Coastal plains exist in areas of stable basement rock as well as in those areas where the basement is sinking.
The coastal plain may include large areas of former sea floor, and the geology of the coastal zone may be very similar to that of the adjacent continental shelf.
Coastal-Plain Aquifers
Aquifers located next to tidal bodies are subjected to short-term fluctuations in the head, due to the tide.
Tidal Effect
