What Is Groundwater? Video Lecture - Class 7

we all know the earth is full of water
but there's a lot more to water than all
that blue stuff you see on the globe the
water we can see on the surface of the
earth is surface water surface water is
every Lake Pend river stream and ocean
on earth but in the ground below your
feet there's even more water groundwater
groundwater is water that's crammed in
the tiny gaps between rocks soils and
sediments under the ground a full body
of groundwater is called an aquifer
there are huge aquifers all across
America the biggest is the High Plains
aquifer which covers a hundred and
seventy four thousand square miles right
in the middle of the country anything of
that big deserves a closer look let's
say you can grab a shovel and dig
straight down through the soils to an
aquifer the level underground where you
first hit groundwater is called the
water table below the water table the
ground is completely soaked or saturated
with water which is why this area is
called the saturated zone the area above
the water table is called the
unsaturated zone so how does all this
water end up in the ground well it's all
a part of the good ol water cycle when
it rains some water gets soaked up by
plants some water runs off the soil and
into streams lakes or even the ocean
other water gets stuck on the surface
and eventually evaporates back into the
air
meanwhile some of the lucky water
droplets get to travel down through the
surface deep underground until they
reach the water table and become a part
of an aquifer once water seeps down deep
enough into the ground it can stay there
for a really long time some of the water
stored in the deepest parts of aquifers
has been there for thousands of years
but after it gets there ground water
doesn't always stay on the ground a lot
of the water on the surface comes from
aquifers if the surface of the ground
dips below the water table groundwater
flows out into the space creating a body
of surface water if the surface water
dries up groundwater can flow in to fill
it back up and if the water table in
this area rises so does the level of the
surface water groundwater can also pour
down a sloping surface creating streams
any place where groundwater flows out
into the surface is called a spring
surface water can also become
groundwater if a body of surface water
flows above the water table water can
seep down through the sediment and help
fill the aquifer of course there's
another way that groundwater can leave
the ground us humans depend on
groundwater and there are thousands of
wells all over the country that draw
water out of aquifers in many parts of
the country the water you get from the
tap comes from the ground however we use
most of our groundwater to help grow the
food we eat Farms can get lots of the
water they need from rain but rain isn't
always enough and in dry years farmers
depend even more on the water that's
stored in the ground
in fact American farms use about 53
billion gallons of groundwater every day
that's enough to fill over a million
bathtubs or 80,000 Olympic sized
swimming pools so if we're using that
much every day can it run out well yes
and no remember aquifers can be refilled
by rain water or surface water seeping
in from rivers and streams so there's
usually more water on its way to
replenish the aquifer but if we use
groundwater faster than the aquifers can
refill we could drain them dry they
probably wouldn't be empty forever but
it would take hundreds of years for the
largest aquifers to get back to healthy
levels whether it's up here or down
there water and how we use it matters we
may not be able to see it every day but
groundwater makes our lives possible so
don't let show-offs like rushing rivers
and roaring oceans get all the attention
those unseen aquifers below ground have
been here longer than we have and with a
little love and care they'll keep on
taking care of us long into the future