Download Watershed: an area or ridge of land that separates waters flowing to

Watershed: an area or ridge of land
that separates waters flowing to
different rivers, basins, or seas. It is
the interdependent web of living
organisms that inhabit a geographic
area and depend on it for clean soil,
air and water. Everything we do,
from mountaintop to marsh, affects
the health of local water, soil, air,
wildlife.
"that area of land, a bounded
hydrologic system, within which all
living things are inextricably linked
by their common water course and
where, as humans settled, simple
logic demanded that they become
part of a community."
The idea that the watershed is on a mountain, and the water
reaches the top of the mountain through the water cycle, and
comes down the mountain through the rivers collecting at the
bottom in a pool
A watershed is an area which acts as a funnel,
collecting water and shunting it into the ocean
or into inland lakes and seas. Watersheds are
also sometimes called catchment areas or
drainage basins, and they are a very important
part of the world's ecology. Because they cross
regional and national boundaries, watershed
management can be extremely challenging,
especially when neighboring nations have
differing views about the best way to manage
the natural environment.
Surface Water: Water flowing on the
earth’s surface
Surface water is water that collects on the surface of the ground. The
collection of surface water can create for example; oceans, lakes,
reservoirs, and rivers. A lake is where runoff surface water has accumulated
in a low spot on earth’s surface. Lake water isn't trapped in one area. The
water entering a lake comes in faster than it can escape. A reservoir is a
manmade lake that is created when a dam is built on a river. The river
water backs up behind the dam which creates the reservoir. One reservoir
in westchester county is the Kensico reservoir. This reservoir receives most
of its water from the City's west-of-Hudson reservoirs through the Catskill
and Delaware aqueducts. This reservoir sits through some town such as
Armonk, Valhalla, Harrison. It supplies about 18 million gallons daily to the
people of these towns. Most reservoirs have an infiltration system which
uses chemicals such as fluoride to treat the water to make is safe for
people to drink. Most reservoirs use a purification system which use a
reverse osmosis system.
Rivers:
-Most of the water you see flowing in rivers comes from
precipitation runoff from the land surface alongside the river
-A river forms from water moving from a higher altitude to a
lower altitude, all due to gravity. -When rain falls on the land,
it either seeps into the ground or becomes runoff, which flows
downhill into rivers and lakes, on its journey towards the seas.
-Some small creeks flow downhill and merge to form larger
streams and rivers
-Eventually end up flowing into the oceans (ultimate goal)
-Essential not only to humans, but to all life on earth
-Plants and animals grow and congregate around rivers simply
because water is so essential to all life
-A lot of cities were built around rivers
-For humans, rivers are diverted for flood control, irrigation,
power generation, municipal uses, and even waste disposal.
Oceans:
- It is estimated that about 96.5 percent of the
world’s water supply is stored in oceans
-The water in the oceans is saltwater (saline) (salt is
dissolved in the water)
-Water is always in movement
-Ocean covers 70% of the earth’s surface
-if the salt in the ocean could be removed and
spread evenly over the Earth's land surface it would
form a layer more than 500 feet (166 meters) thick,
about the height of a 40-story office building
• A lake is where runoff surface water has
accumulated in a low spot on earth’s surface.
• Lake water isn't trapped in one area. The water
entering a lake comes in faster than it can escape.
• Lakes are home to many different organisms such
as plants, insects, amphibians, mammals.
• Lakes can become polluted from fertilizers and
pesticides, raw sewage gets dumped into
waterways which makes it into lakes, sediment
from landscapes can wash into lakes.
• Reservoirs:
• The collection of surface water can create for example;
oceans, lakes, reservoirs, and rivers.
• A reservoir is a manmade lake that is created when a dam is
built on a river.
• The Kensico reservoir is in westchester going through towns
such as Armonk, Valhalla, Harrison.
• It supplies about 18 million gallons daily to the people of
these towns.
• This reservoir receives most of its water from the City's westof-Hudson reservoirs through the Catskill and Delaware
aqueducts.
• Most reservoirs have an infiltration system which uses
chemicals such as fluoride to treat the water to make is safe
for people to drink.
• Most reservoirs use a purification system which use a reverse
osmosis system.
Underground River
• Some areas of the crust are so absorbent that water gathers deep
underground.
• If the crust’s material is more easily eroded underground, the water
will begin to flow under the surface.
• A Underground River is a stream running under the earth.
• A famous underground river is Puerto Princesa Underground River
• Knowing where groundwater comes from provides a better
perspective of how groundwater can become contaminated from
land uses.
• Because groundwater originates as precipitation sinking down from
the land surface, downward-infiltrating water must pass through
whatever is at or below the surface.
• At any given location, groundwater tends to be harder and more
saline than surface water, but this is by no means a universal rule. (2)
• It is also generally the case that groundwater becomes more
saline with increasing depth.(1)
• Engineers must consider groundwater when planning almost
any kind of structure, either above or below the ground.
• Ignoring the effect of groundwater on slope stability can be
both costly and dangerous.
• The fluid pressures exerted by groundwater, for example, play
an important role in the occurrence of earthquakes.(3)
• The movement of water through underground geologic
formations controls the migration and the accumulation of
petroleum and the formation of some ore deposits.(3)
Groundwater moves so slowly that problems take a long time
to appear.
• In result of this and because of how expensive it is to clean up
a contaminated aquifer it is preferable to prevent
contamination from happening in the first place.
• Aquifers:
• An aquifer is an underground layer of permeable rock and solid
material such as gravel, sand, or silt which groundwater can be
taken out using a water well.
• Aquifers can be contaminated by harmful chemicals that can seep
down through the rock and soil into aquifers
• Aquifers can recharge by precipitation into the porous rock
• A confined aquifers are when the porous rock become tilted and
both of the less porous rock are above and below the porous layer.
There is a possibility of a layer with less porous rock. The result of
this is when the well is drilled, the pressure makes the water move
up into the well without any aid of a pump which is an artesian well
• Water Table: The level below which the ground is filled with water
• The movement of water depends on how permeable the rock is
• Unconfined Aquifer: Also known as the Water table well. An aquifer
which has the water table as the upper boundary. Occurs near the
ground surface.
• Artesian aquifers is a confined aquifer that has groundwater under
positive pressure
Water Treatment:
screening
• First unit operation used at wastewater treatment plants
removes objects such as rags, paper, plastics, and metals to
prevent damage and clogging of downstream equipment,
piping, and appurtenances.
• Modern water waste treatment plants use coarse screens
and fine screens to filter out large and small objects
• Coarse screens remove large solids, rags, and debris from
wastewater, and typically have openings of 6 mm (0.25 in)
or larger.
• Fine screens are typically used to remove material that
may create operation and maintenance problems in
downstream processes, particularly in systems that lack
primary treatment. Typical opening sizes for fine screens
are 1.5 to 6 mm typically at the bottom of the resevoir
and
Chlorination
• Chlorination is one of many methods that can
be used to disinfect water.
• It is a chemical disinfection method that uses
various types of chlorine or chlorinecontaining substances for the oxidation and
disinfection of what will be the potable water
source.
Ozonation
• Today, it is the most commonly used disinfection
process in Europe.
• Ozone is used in the same manner as chlorine.
The major difference is that ozone is unstable so
cannot be produced and transported to the point
of use. For water treatment, Ozone can injected
or diffused into the water supply stream.
• Ozone is extremely active as a disinfectant.
• A wider range of organisms is killed by ozonation
than by chlorination. It also achieves excellent
removal of taste and odors.
Fluoridation
• Water fluoridation is the controlled addition of fluoride to a
public water supply. It is used to prevent tooth decay and
prevent cavities.
• This process has helped strengthen teeth and reduce tooth
decay by 25 %
• The United States has been using fluoridation for 70 years
• The three additives are
– Fluorosilicic acid
– Sodium fluorosilicate
– Sodium fluoride
• These additives do not affect taste, color, or smell of the
water
• The maximum amount of fluoride in the water can be 0.7
milligrams per liter
Reverse osmosis
• By applying pressure to the water solution of higher
concentration (the incoming water), the flow of liquid
is reversed. Under these conditions, the membrane
still rejects the contaminants, but allows the fresh,
cleansed water to pass through. The purified water is
then stored in a holding tank and the contaminants
are flushed away. This process is typically used to
remove sodium from the water, but will also remove
arsenic, uranium, nitrates, lead and range of other
potential contaminants.
• process responsible for removing salt from water.
• In Perth, Australia (notably dry and arid, yet
surrounded by sea), nearly 17 percent of the area's
drinking water is desalinated sea water that comes
from a reverse osmosis plant