Transcript ES-8 PPT Freshwater Resourcesx

Freshwater Resources
ES 8
Learning Target
ES-8A
• Compare and contrast the various types of
weathering (i.e., physical and chemical),
including their products.
• Describe the process through which soil is
developed and explain the soil horizons as a
part of this.
Mechanical Weathering
• Mechanical weathering occurs when physical
forces break the rock into small pieces without
changing the mineral composition.
Frost Wedging
• Frost wedging – the mechanical weathering of
rock caused by expansion of freezing water in
cracks and crevices
Sheeting / Exfoliation
Exfoliation Type of weathering
caused by reducing
pressure on a rock
surface, allowing slabs of
outer rock to break off in
layers.
Root Wedging
• Type of physical weathering, where root
growth pries apart rocks.
Abrasion
• Type of mechanical weathering, where the
corners and edges of rocks are broken off by
physically hitting other rocks and sediments.
Chemical Weathering
• Chemical Weathering - The transformation of
a rock into one or more compounds. (The rock
is chemically changed)
Oxidation
• Type of chemical weathering (rusting), where
minerals in rock react with oxygen and
chemically change. (common in iron rich
rocks)
Silicate Chemical Weathering
• The minerals in silicate rocks can weather
chemically. Water combines with the minerals
chemically changing them.
Water / Carbonic Acid / Acid Rain
• Water combines with carbon dioxide creating
carbonic acid. (why soda kills teeth). This
acidic water dissolves carbonate rocks.
Erosion
• Erosion is the transportation of sediments by
an external agent. Water, wind, ice, gravity
Water Erosion
• Water has the greatest
erosive effect.
• The faster the water
moves the more energy
it has.
– The more energy water
has, the greater the size
and amount of
sediments are moved.
• Wind carries sediment away.
• The faster the wind blows, the more sediment
it can carry.
Gravity
• After sediments are weathered and separated
from the rock, they can
.
Causes
•
•
•
•
•
Removing vegetation
Heavy Rains saturating slopes
Over steep slopes
Earthquakes
Any combination of the above
Mass Movement
• Mass wasting is when large amounts of
sediments are being moved at a time. (Rockslide)
Slump
Glaciers
• Glaciers = permanent ice on mountains.
– The glacier constantly moves downhill, or away
from center.
Glaciers
• Ice both weathers and erodes rocks
– Think of a river of ice
River Valley vs Glacial Valley
Soil Formation
• Soil has 4 major components: Mineral matter
(from rocks), humus (organic matter), water,
and air.
Soil Texture
Soil Profiles
• Soil profiles are a
vertical section of soil
showing its succession
of horizons and the
underlying parent
material.
Learning Target
ES8 B: The development of karst
topography.
Analyze the formation of karst in terms of rock
type, solubility and permeability, uplift, the
water table, and chemical and physical
weathering.
How does Karst Develop?
1. Start with a
landscape of
carbonate
rocks.
(Limestone,
dolostone)
Acid Water
2. Add acidic water
– Water + Carbon Dioxide
= Carbonic Acid H2C03
– All rain is acidic,
groundwater becomes
acidic
3. Acidic water then
dissolves the
carbonate rocks
Features of Karst Topography
Stalagmite vs Stalactite
• Stalactites are on the
ceiling
• Stalagmites are on the
Ground
• Formed from calcite
being left behind when
water drips from the
ceiling and hits the floor
Sinkholes
• Sinkholes occur when the rock beneath the
surface is no longer strong enough to hold it
up.
Learning Target
ES8 C: Relationships between groundwater zones, including
saturated and unsaturated zones, and the water table.
Interpret a simple groundwater diagram showing the zone of
aeration, the zone of saturation, the water table, and an
aquifer.
ES8 D: Identification of sources of fresh water including
rivers, springs, and aquifers, with reference to the hydrologic
cycle.
Interpret a simple hydrologic cycle diagram, including
evaporation, condensation, precipitation, and runoff.
Analyze the presence of groundwater in various types of rock
terrains, including areas found in each of the physiographic
provinces of Virginia.
Water Cycle
Evaporation
• Evaporation – Water changes from liquid to
vapor. Heat captured
• Transpiration – Trees absorb water, then they
expel water vapor through the leaves.
Condensation
• Condensation – As the air cools, water
changes from vapor to liquid.
– Water condenses on dust particles in the air called
condensation nuclei.
– Heat is released.
Precipitation
• Precipitation – Liquid water in the atmosphere
is released from the sky, falling to the Earth
– Rain – Liquid water
– Snow – Crystallized Water
– Sleet – Frozen water
– Hail – Frozen water, formed from circulation in
storm clouds
Run-off
• Water pools on the Earth and flows down hill
toward the oceans.
– Rivers – fast moving water
– Lakes – Do I need to explain this?
– Groundwater
• Water flows down the water table
• Can be trapped underground for thousands of years
Ground Water Space
• Porosity – The spaces in the soil
– Can be filled with water and air
– If totally filled with water = Saturation
– If not totally filled with water = not saturated
Ground Water Movement
• Permeability – The ability for water to move
through soil.
– Sandstone, high porosity, high permeability
– Limestone, low porosity, high permeability
Ground water profile
Ground Water Lake?
• Aquifer – Layer or layers of rock with high
enough porosity to hold water, and high
enough permeability for the water to move.
Learning Target
• ES 8 E: Dependence on freshwater resources and the
effects of human usage on water quality
• Analyze the relationship between salt-water intrusion
in the groundwater in certain areas of eastern Virginia
and buried crater structures.
• ES 8 F: Identification of the major watershed systems
in Virginia including the Chesapeake Bay and its
tributaries.
• Locate major Virginia watershed systems on a map
(Chesapeake Bay, Gulf of Mexico, and North Carolina
Sounds).
Ancient Meteorite Crater
Estuary
• An estuary is a partly enclosed coastal body of
brackish water with one or more rivers or
streams flowing into it, and with tidal
influences from the sea /ocean
Estuary Types
• Drowned river valley – Chesapeake
Other Estuaries
• Bar-built – Sand bar
blocks river
• Fjord – Flooded Glacial
valley
• Tectonic – Land moved
via regional tectonic
activity
Fjord
Fjord
Tectonic
Estuary
Bar Built Estuary
Virginia Watersheds
• Virginia has 3 main watershed destinations.
– Chesapeake
– North Carolina
– Mississippi
• There is also the Atlantic, but it is only on half
of the Eastern Shore.
Chesapeake Bay Watershed
• Rivers you MUST know
– James (VA)
– York (VA)
– Rappahannock (VA)
– Potomac (VA)
– The Susquehanna (MD, PA, NY)
• Largest River of the Chesapeake
• 50% of the water volume
Enrichment!
• Map of the Chesapeake Bay watershed.
– Trace around the 5 major river watersheds
• James, York, Rappahannock, Potomac, and
Susquehanna.
• You may use your internet to locate them.
North
Top 10
Ways to protect our water sheds
– You need to memorize any four of these 10 ways
to protect our watersheds.
• Find ways to implement these four into your
lifestyle. Be ready to discuss these methods
intelligently with the class and the teacher.
Geologic Provinces of Virginia