Groundwater originates from water that infiltrates through soil and rock below the earth's surface. It is found in aquifers, which are saturated geological formations that are capable of providing usable quantities of water. The main sources of groundwater are meteoric water from rainfall and snowmelt, connate water trapped in sediments when they were deposited, and magmatic water from volcanic activity. Groundwater composition varies depending on the geology, but common dissolved ions include bicarbonates, carbonates, chlorides, sulfates, fluorides, calcium, magnesium, sodium, and manganese.
1. M G SCIENCE INSTITUTE
GEOLOGY DEPARTMENT
ORIGIN,TYPE AND COMPOSITION OF GROUND
WATER
Name : Chaudhary Mihirkumar A
Roll No : 2
M.Sc Sem : 4
Supervision By Dr.P.M.Solanki Sir
2. WHAT IS GROUNDWATER
Groundwater is fresh water located in the subsurface pore space of soil and rock it is also water that is flowing within aquifers
below the water table
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3. Groundwater is water, which originates from the infiltration of fluids through the soil profile and accumulates below the earth's
surface in a porous layer
Porosity is the percentage of open void space in the subsurface material. It is expressed as a percent
Permeability is how readily a fluid can flow through a material. Often referred to as "connected pore space"
Piezometric surface is the surface in which water is pushed up to by the pressure below
Spring is where water flows out without the aid of pumping. It may be caused by hydrostatic pressure (pressure pushing
upward), or the intersection of the piezometric surface with the ground surface. Also referred to as an Artesian System
An aquifer is the porous unit or layer of rock that is able to store or hold water and transmit enough fluid to be of economic
value
An aquitards is rock material that do not contain water but allows water to pass through it. Fluid flow is not good and the unit
may often be termed a "cap rock", not allowing underlying water to flow upward
4. Confined Aquifer : when an aquifer is bounded by two aquitards (one above and one below)
A confined aquifer below the land surface that is saturated with water
Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer
is penetrated by a well , the water will rise above the top of the aquifer
Unconfined Aquifer : when an aquifer is not bounded on the surface side by an aquitard so that fluids may flow freely above the
aquifer
A unconfined aquifer is an aquifer whose upper water surface is at atmospheric pressure , and thus is able to rise and fall
6. The distribution of groundwater is present in several distinct layers or zones:
a. Soil moisture zone : usually top soil; much infiltration; much organic material
b. Zone of aeration (Vadose Zone) : mostly air but some interstitial water
c. Capillary fringe : transition between unsaturated and saturated zone; top of aquifer
d. Zone of saturation (Phreatic Zone) : pores completely saturated with water; main aquifer storage zone
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7. ORIGIN AND TYPE OF GROUND WATER
Total water existing on earth is 1,38,41,20,000 cubic kms, out of which 80,00,042 cubic kms is groundwater. Apart from this,
61,234 cubic kms is in form of soil moisture.
Groundwater and soil moisture together constitute the sub-surface quantity of water. Groundwater is stored in different layers of
earth by infiltration through pores and fissures of permeable rocks.
Groundwater mainly comes from three sources.
They are, First: ‘Meteoric Water’, which is the main source of groundwater and is received in the form of rain and snow.
This water infiltrates from the surface through fissures, pores and joints of rocks till it is stored on non-permeable rocks in the
form of groundwater; Second: ‘Connate Water’, which exists in pores and cavities of sedimentary rocks of seas and lakes.
It is also called sedimentary water. Thirdly: ‘Magmatic Water’ which converts into water after condensation of vapour as a
result of volcanic action at the time of entering hot rocks.
8. The main source of groundwater is rainfall.
It infiltrates through seepage slowly into the earth and collects there. It is also called ‘plutonic water’.
Groundwater is an important part of the water cycle, which also includes that part of surface and atmospheric water which goes
underground through rainfall, rivers and lakes.
Sources of Groundwater: Water received on the surface of the earth from different sources becomes groundwater when it goes
underground after information through pores of permeable rocks.
1. Meteoric Water: This is the main source of groundwater.
This water is received in the form of rain and snow.
Water from tanks, lakes, rivers and seas is again received by earth after vaporization.
Water is received by melting of snow or rain, hence it is called ‘meteoric’ or ‘shooting star water’.
9. From the surface of the earth, this water infiltrates down below through rock joints, pores and fissures of rocks and is stored at
the level of impermeable rocks in the form of groundwater.
It originates in the atmosphere, falls as precipitation and percolates through the soil to become groundwater.
You may have noticed the fluctuation of the water level in wells.
During the rainy season the level goes up, while in the summers the level goes down.
This is indicative of the fact that groundwater significantly depends upon water from the atmosphere. Another way in which the
groundwater may be derived directly from atmospheric moisture is condensation of water vapour from air circulating through
the pores and interstices.
This is also known as ‘condensational water’ and is the basic source of replenishment in the arid and semi-arid areas.
During summers, the land is warmer than the air in the soil. This results in a difference of pressure between the water vapour in
the atmosphere and the soil.
10. The water vapour from the atmosphere penetrates into the rocks as the temperature of the water vapour drops in the cooler soil.
A certain amount of water may accumulate this way. A third source is effluent seepage from lakes, rivers, oceans and also man-
made channels, but the importance of this varies with the climate of the area concerned.
In fact, in humid regions, the groundwater contributes to stream flow by means of effluent seepage, and the gradient of this
saturated groundwater more often than not slopes towards the surface water bodies and the oceans.
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11. 2. Connate Water: Water contained in pores and cavities of sedimentary rocks under seas and lakes is called connate water. It is
also called ‘sediment water. It is the second important source of groundwater.
This is the water that is entrapped in the interstices of sedimentary and volanic rocks at the time of deposition.
Connate water is highly mineralized and salty and does not mix readily with meteoric groundwater.
Connate water is usually found deep down in the lower layers of the zone of saturation.
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12. 3.Magmatic Water: Hot magma enters rocks due to volcanic action after which its vapour drops are condensed and converted into
water.
This is called magmatic water. Apart from it, other sources are those in which groundwater becomes again available on the
surface of the earth.
They are mainly springs, wells, and geysers. Such water is considered to have been generated in the interior of the earth.
It has consequently travelled to the upper layers of the earth’s surface for the first time; this is also known as magmatic water.
13. COMPOSITION OF GROUND WATER
Natural inorganic constituents commonly dissolved in water that are most likely to affect water use include:
• Bicarbonate
• Carbonate
• Chloride
• Sulphate
• Fluoride
• Iron
• Magnesium
• Calcium
• Sodium
• Manganese
14. Major Cations
• The cations which are present in greater concentration (almost always greater than 1mg/L) are called the major cations.
Calcium (Ca2+)
Magnesium (Mg2+)
Sodium (Na+) •
Potassium (K+)
Major Anions
• The anions which are present in higher concentrations (normally higher than 1mg/L) are called major anions.
Bicarbonate (HCO3)-
Sulfate (SO4)2-
Chloride (Cl-)
15. Minor ions
• Cations and anions present in the concentration range of 0.01-1.0mg/L are know as minor ions.
Iron
Manganese
Nitrate
Ammonium
Hydrogen Sulfide
Fluoride
Boron