Condensation is the change of the physical state of matter from gas phase into liquid phase, and is the reverse of evaporation. The word most often refers to the water cycle.
Hydrogeology (hydro- meaning water,
and -geology meaning the study of
It is the area of geology that deals with
the distribution and movement
of groundwater in the soil and rocks of
the Earth's crust (commonly in aquifers).
The hydrologic cycle begins
with the evaporation
of water from the surface of the
ocean. As moist air is lifted, it
cools and water vapor
condenses to form clouds.
Moisture is transported around
the globe until it returns to the
surface as precipitation.
contribute tocontribute to
groundwatergroundwater, which is stored, which is stored
in underground reservoirsin underground reservoirs
until it surfaces as a spring oruntil it surfaces as a spring or
is drawn from a well.is drawn from a well.
• process of waterprocess of water
moving into themoving into the
• to penetrate,to penetrate,
enter or gainenter or gain
I. Water Beneath the SurfaceI. Water Beneath the Surface
Groundwater:Groundwater: underground waterunderground water
that fills almost all of thethat fills almost all of the
pores/voidspores/voids in rocks andin rocks and
AquiferAquifer:: a body ofa body of rockrock that can storethat can store
water and also let water flow throughwater and also let water flow through
Think of an AQUIFERAQUIFER as
• large, horizontal spongesponge that
absorbs and transports water
along its length
An aquifer is an underground layer of water-
bearing permeable rock, rock fractures or
unconsolidated materials (gravel, sand, or silt)
from which groundwater can be extracted using a
It is porous & permeable to the extent of
maintaining a steady supply of sufficient amount
of water to the wells or springs.
Occurrence of Groundwater in different terrains –
•Weathered – pore spaces & voids/openings
•Hard and Stratified rocks – cracks & fractures
Aquifer : A saturated, permeable, geologic unit / formation or
group of formations that can yield a significant amount ( sufficient
quantity) of groundwater to be called as a source of supply.
Aquiclude :A saturated geologic unit which yields inappreciable
quantity of water to drain & through which there is inappreciable
movement of water.
Aquitard : A saturated, permeable, geologic unit / formation or
group of formation which yield water in appreciable quantity to
drain completely to an aquifer but through which appreciable
leakage of water is possible.
Aquifuge : A formation that does not store any water.
FACTORS THAT INFLUENCEFACTORS THAT INFLUENCE
(a) SORTING: amount of
uniformity in particle size
HIGH pore space LOW pore space
(b) SHAPE:(b) SHAPE: rounder particles =
(c) PACKING:(c) PACKING: loosely packed =
Permeability: It is the property by virtue of
which the rock/ geological formation allows
water to travel through its pore spaces or other
2. Permeability: how freely water
flows through open spaces in a
rock (the pores must be connected)
Impermeable – water can NOT flow through
It is the measure of the quantity of water passing
through a unit cross section in a unit time & 100 %
Can something be porous butCan something be porous but
• The cork end isThe cork end is
red because thered because the
grape juice wentgrape juice went
into it. Does thisinto it. Does this
mean it is porous?mean it is porous?
• If you turn theIf you turn the
bottle upside downbottle upside down
will it leak? Is thewill it leak? Is the
cork permeable?cork permeable?
A permeable rock is always porous but a porous rock may not
always be permeable
Porosity & permeability depend on width of fracture,
frequency, distribution & orientation .
Fine grain sediments have the tendency to hold up
water against the force of gravity
Coarse grained well sorted sediments yield water
In case of consolidated rocks, dimensions of
secondary openings, joints, cavities largely control
the specific yield.
Specific retention depends on total interstitial surface
in the rock.
B. Zones of GroundwaterB. Zones of Groundwater
1.1. Zone of Saturation:Zone of Saturation: the layer ofthe layer of
ground where all the pores areground where all the pores are
filled with water.filled with water.
2.2. Water Table:Water Table: upper surface ofupper surface of
the zone of saturationthe zone of saturation
3.3. Zone of Aeration:Zone of Aeration: upper region,upper region,
where water is both in the soil andwhere water is both in the soil and
seeping down to the water table.seeping down to the water table.
• Capillary Action:
ability of water to
rise UP the soil.
• Smaller particle size =
Capillary Fringe:Capillary Fringe: middle layer,middle layer,
between the water table and thebetween the water table and the
zone of aeration.zone of aeration.
C. MOVEMENT OFC. MOVEMENT OF
• Depends on:
1. Permeability of the aquifer
• ↑ permeability = ↑ velocity
1. Gradient of the water table
• Gradient = steepness of the
• ↑ gradient = ↑ velocity
II. Wells and SpringsII. Wells and Springs
• Water Table:Water Table: upper layer of rocksupper layer of rocks
with all pores filled with water.with all pores filled with water.
A. Ordinary Well:A. Ordinary Well: A hole dugA hole dug
below the water table which fillsbelow the water table which fills
up with water.up with water.
Cone of Depression:Cone of Depression: lowered arealowered area
of the water table due to pumpingof the water table due to pumping
B. Artesian Wells: water flows
freely with no pumping
• Underground water
layers) rises to the
• Water is naturally
filtered as it passes
rock and seeps to
III. Groundwater andIII. Groundwater and
Chemical WeatheringChemical Weathering
A.A. Caverns:Caverns: rocks rich in calciterocks rich in calcite
(limestone) slowly dissolved(limestone) slowly dissolved
by carbonic acid.by carbonic acid.
• Hard water = many dissolvedHard water = many dissolved
minerals (Ca, Mg, Fe)minerals (Ca, Mg, Fe)
• Soft water = few dissolvedSoft water = few dissolved
1. Stalactites:1. Stalactites: water withwater with
dissolved calcite runs from adissolved calcite runs from a
cave’scave’s ceilingceiling and solidifiesand solidifies
2. Stalagmites:2. Stalagmites: calcite richcalcite rich
water drips on the cave’swater drips on the cave’s floorfloor
and builds upward.and builds upward.
If the twoIf the two
then itthen it
forms aforms a
3. Natural3. Natural
Bridge:Bridge: when thewhen the
roof of a cavernroof of a cavern
collapses incollapses in
several placesseveral places
leaving an arch-leaving an arch-
shaped rock.shaped rock.
B. KARST TOPOGRAPHYB. KARST TOPOGRAPHY
• regions where chemical weathering
by groundwater is now visible at the
• regions where it is humid and there
are limestone formations near the
• Virginia, Kentucky, Tennessee,
Indiana, and Florida have Karst
1. Sinkholes1. Sinkholes (the main feature(the main feature
of Karst Topography)of Karst Topography)
How do sinkholes form?How do sinkholes form?
• Rain seeps through soil and absorbsRain seeps through soil and absorbs
carbon dioxide and reacts with decayingcarbon dioxide and reacts with decaying
• Acidic water is createdAcidic water is created
• Water moves through spaces and cracksWater moves through spaces and cracks
• Limestone is slowly dissolved, creatingLimestone is slowly dissolved, creating
network of cavities and voidsnetwork of cavities and voids
• Pores and cracks enlargePores and cracks enlarge
• Land surface above collapses or sinksLand surface above collapses or sinks
2. Streams that disappear in2. Streams that disappear in
the groundthe ground
Like Lewis Creek in Staunton