Transcript Fresh Water - PAMS-Doyle

Fresh Water
Fresh Water
• Most of the Earth’s fresh
water is found in moving
water and in standing water.
• Rivers, streams, and springs
are moving water, ponds,
lakes, and swamps are
standing water.
Water Cycle
• The water cycle – the movement of
water from the oceans and
freshwater sources to the air and
land and finally back to the oceans.
• Evaporation – the process of water
to gas phase.
• Condensation – the process of gas
to water. Must be cooled for this to
occur.
• Precipitation – water returns to the
Earth in the form of rain, snow, sleet,
or hail.
Where is the rest of the
water?
• Groundwater – the water that remains in the
ground. Eventually flows into the ocean. Some
of this returns to the earth from springs
• Frozen water
– Glaciers
• A. Valley glaciers – long, narrow glaciers that
move downhill between mountain valleys.
• B. Continental glaciers – thick sheets of ice that
covers millions of square km of the earth’s
surface, moves slowly in all directions.
• C. Icebergs – Some are as large as Rhode Island
Valley and Continental
Glacier
Running Water
Pore space
• Surface runoff – the water that enters a
river or stream after a heavy rain or
spring thaw.
• Pore space – the space between
particles of soil. More pore space =
more water it can hold.
• Watershed – a land area in which
surface runoff drains into a river or a
system of rivers and streams.
Standing Water
• Lakes – usually deep depressions in
the earth’s crust filled with fresh
water. Usually where glaciers once
were.
• Ponds – shallow depressions with
fresh water, plants usually
throughout.
• Reservoirs – the most frequently
used source of fresh water. Built by
damming a stream or river and is
protected from polluting by laws.
Lakes, Ponds, and
Reservoirs
POND
RESERVOIR
LAKE
Wetlands
• Wetland: land area covered with water for most of
the year, serves as a filtering system that traps
pollutants, sediments and bacteria, houses birds
and other wildlife
1. Bog: get their water from precipitation only, very acidic soil, grows
unusual plants such as peat moss and the Venus Fly Trap
2. Marsh: form in areas with deltas, grows shallow rooted marsh grasses
which aid in the deposition of silt and sand
3. Swamp: located near streams, contains shrubs and tree’s, after
millions of years the decayed plant material forms coal
• Preservation of wetlands has become a global
concern, between the 1700’s and the 1980’s
over 50% of the USA and Europe has lost
wetlands due to population growth and
industry
Groundwater
• Present because the types of precipitation
does not stop traveling when it hits the
ground, it moves downward through the
permeable areas
• Permeable: material in which the water can
move quickly, sandstone has a high
permeability rate
• Impermeable: water does not flow through
the ground easily, clay is impermeable
Underground Zones
• When groundwater reaches a layer of
impermeable rock it fills up the pore spaces
above forming a zone of saturation
• Above the water filled zone is an area that is
mostly dry, this drier region where the pores
are filled with air is called the zone of aeration
• The area between these two zones marks the
boundary where the ground is saturated and is
called the water table
Water Table
• When you dig in the soil and reach a point
where the hole fills with water you have
located the water table
• Hills and mountains the water table is deep,
valleys, marshes and swamps the water
table is closer to the surface
• Deserts have a deep water table, while wet
climates have it near the surface
• Water table can change depth when there
are times of drought or heavy rains/snow
fall or if wells are being overused
Wells
• Holes drilled or dug into the water table
• Aquifer: Layer of rock that allows water to pass
freely and moves sideways. Usually layers of
sandstone, gravel, sand or cracked limestone
• Found when a permeable layer gets trapped in
between two impermeable layers
• Is a source of groundwater for wells
• Since the water moves underground over very
large distance it is vulnerable to pollution which
can contaminate the whole aquifer quickly
• Artesian Well: A well from which water flows on
its own without pumping
• Aquicludes: Barriers to groundwater flow
Groundwater Systems
• Springs: water discharges at the surface
where aquifers and aquicludes meet
• Temperature varies from cool to hot, is
generally the average annual temperature
of the region
• Hot Springs: water from deep in earth has
risen
• Geysers: explosive hot springs that erupt
at regular intervals
Groundwater
Composition
• Water can contain compounds that are
not hazardous such as iron (red) or
sulfur (egg smell) compounds.
• Hard Water: Water contains high
concentrations of calcium, magnesium
or iron, common in limestone regions.
It can clog your pipes
• Soft Water: makes soap more slippery,
very little minerals present
Solubility
• Solvent – the substance that does
the dissolving. Water is the
universal solvent.
• Solute: the substance that gets
dissolved
• Solution – contains two or more
substances mixed on the molecular
level, one thing must be dissolved.
• Soluble – can be dissolved.
• Insoluble – cannot be dissolved.
http://www.tes.co.uk/teachingresource/Fresh-water-beneath-thesurface-of-the-earth-6286763/
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