Transcript Groundwater

Groundwater
is water located beneath the ground
surface in soil pore spaces and in the
fractures of lithologic formations.
Groundwater can be found at nearly every point in the
Earth's shallow subsurface, to some degree; although
aquifers do not necessarily contain fresh water.
The Earth's crust can be divided into two regions: the
saturated zone where all available spaces are filled
with water, and
The unsaturated zone, where there are still pockets of
air with some water that can be replaced by water.
An uncontrolled use of the borewell
technology has led to the extraction of
groundwater at such a high rate that
often recharge is not sufficient.
The causes of low water availability in many regions
are also directly linked to the reducing forest cover
and soil degradation.
The solid, liquid, and the gaseous waste
that is generated, if not treated properly,
results in pollution of the environment;
this affects groundwater too due to the
hydraulic connectivity in the
hydrological cycle
Example, when the air is polluted, rainfall will settle
many pollutants on the ground, which can then seep
into and contaminate the groundwater resources.
Water extraction without proper
recharge and leaching of pollutants
from pesticides and fertilizers into the
aquifers has polluted groundwater
supplies.
Aquifers are typically saturated
regions of the subsurface which
produce an economically feasible
quantity of water to a well or spring
Most land areas on Earth have some
form of aquifer underlying them,
sometimes at significant depths.
An aquitard is a zone within the earth
that restricts the flow of groundwater
from one aquifer to another
There are two end members in the
spectrum of types of aquifers;
confined and unconfined
Unconfined aquifers are sometimes also called
water table aquifers, because their upper boundary
is the water table. Typically (but not always) the
shallowest aquifer at a given locationis unconfined,
meaning it does not have a confining layer (an
aquitard or aquiclude) between it and the surface
Confined aquifers have very low
storativity values (much less than
-5
0.01, and as little as 10 ), which
means that the aquifer is storing
water using the mechanisms of
aquifer matrix expansion and the
compressibility of water, which
typically are both quite small
quantities.
The Ogallala Aquifer, also known as
the High Plains Aquifer, is a vast yet
shallow underground water table
aquifer located beneath the Great
Plains in the United States.
Global Warming Effects?
Groundwater recharge will rise dramatically
in some areas and decrease in others — a
direct result of soil-water-plant systems,
which control it, amplifying the effects of
rainfall variations. Because many countries
have groundwater reservoirs that constitute
a significant portion of their total water
supply.
It is vital that policymakers and scientists gain a
better understanding of the complex interactions
between the climate, soil and groundwater.
Doing so will allow us to predict future changes
in the soil-water-plant systems more accurately
and will also enable us to institute better water
management practices when the time comes.