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 |   About Grounwater and Hydrogeology  Mon May 16, 2011 11:31 am | Bài viết số 1 |
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 Địa
chất thủy văn là một nhánh của khoa học trái đất nghiên cứu về nước
dưới đất, nghĩa là nghiên cứu về sự hình thành, vận động, phân bố của
nước trong các lỗ hổng, khe nứt.. trong các thành tạo đất đá của vỏ trái
đất.
Lâu
ngày chúng ta mải mê nghiên cứu, làm ăn lo cuộc sống hàng ngày, nhiều
khi quên đi những khái niệm cơ bản về lĩnh vự khoa học này.
Chúng
tôi xin trích dẫn lại dưới đây những khái niệm cơ bản nhất về vấn đề
này do Cục Địa chất Mỹ đăng tải để mọi người tự tìm hiểu.
About Groundwater (Khái niệm về nước dưới đất)
A hidden resource (là nguồn tài nguyên tiềm ẩn)
When
we think of fresh water we probably think of rivers, lakes and perhaps
reservoirs. Yet even when we consider the huge lakes of North America or
mighty rivers like the Amazon and the Ganges, over 97% of the planet's fresh water is to be found under the surface of the earth in the form of groundwater.
In
many parts of the world groundwater is the main source of water for day
to day use. Boreholes driven down into the saturated layer under the
ground yield water for irrigation and urban use. At least 1,500 million
urban dwellers are supplied with water from groundwater reserves. It is
also extensively used as a low cost rural water supply.
Groundwater has many benefits. It is cheap to develop
because of its naturally good quality and widespread occurrence. It is
reliable even in times of drought due to the large amounts stored under
the surface. It is also protected against catastrophic events - if
natural disasters or war disrupt surface water distribution, then
groundwater reserves can easily be developed.
Some
areas near the surface may not be saturated with water and only have an
intermittent supply of water. But, many areas deeper under the surface
are saturated with water accumulated over hundreds or even thousands of
years. These areas often supply permanent springs and can be tapped with
boreholes to provide water. When we draw groundwater from deep aquifer
supplies, we are tapping into water locked away under the surface and
filtered through layer upon layer of rock. This is one of the reasons
why groundwater is so reliable. The water in these areas may even be
protected against recent surface pollution, providing a high quality
supply where none was previously available.
Hydrogeology
What is Hydrogeology? (ĐCTV là gì ?)
Hydrogeology
is a branch of geology, the study of rocks and the structures that are
formed over vast periods of time. The way that sediments have been
deposited to create different layers of rock beneath the surface, or the
way that rocks have been heated and folded over millions of years to
create complex structures are the subjects of geology.
Hydrogeology
looks at how water interacts with geological systems. But there is more
to hydrogeology than wet rocks. Water is a vital natural resource for
people all around the world - whether it is piped to homes or drawn out
of wells. Understanding where it is and how it moves under the ground is
essential in protecting this resource.
By
using geological maps and taking samples of underground and surface
water for analysis, hydrogeologists are able build detailed pictures of
how water flows through porous rocks underground.
Why is Hydrogeology important? (Tại sao ĐCTV lại quan trọng đến thế ?)
Some
parts of the world are blessed with frequent rainfall and plentiful
surface water resources, but most countries need to use the water that
is stored underground to supplement their needs. Hydrogeologists can
help by locating suitable reserves and by assessing how much water it is
possible to extract without permanently damaging underground aquifers
or surrounding ecosystems.
By
looking at the way that groundwater flows, hydrogeologists can also
identify when it is at risk from pollution and how we can protect it by
careful planning and land-use. Without the knowledge that hydrogeology
gives us we have no way of predicting what will happen to our water
resources or the future effects on the environment of water extraction.
(Nguồn: Hội địa chất thủy văn Việt Nam)
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