the water cycle this is where it all begins. infiltration ( also called percolation ) only happens...
TRANSCRIPT
the Water Cyclethis is where it all begins
Infiltration (also called percolation)only happens when the ground is permeable
Permeable Impermeable
water can pass through water cannot pass through
sedimentary rocksand & silt
loamcompost / humus
igneous & metamorphic rock*bedrock layer
clayasphalt / concrete
Groundwaterwater stored underground
Zone of aeration – Unsaturated zone – Pore spaces in the material are filled mainly with air
Zone of saturation (also called an Aquifer)– Pore spaces in the material are filled with water –Water within the pores is groundwater
Water table --the upper limit of the zone of saturation water table can move up when it rains or down during a drought
• Aquitard – an impermeable layer of material • Aquifer – a permeable layer of material
Two Types of Aquifers
type of aquifer unconfined confined
descriptionwater rests on an impermeable
layer; ground above it is permeable; can be refilled from
rainwater that infiltrates
water trapped between 2 impermeable layers; water becomes pressurized; cannot be refilled from
rainwater infiltration
type of wellregular well
(water needs to be drawn or pumped out)
Artesian well (water rises under its own pressure)
Springs
• Spring – groundwater that
emerges naturally from the surface
– when the water table intersects with the surface of Earth
Porosity & Permeability• Porosity – amount
of water that can be stored in the pore spaces
• Permeability – ability of water to flow through connected pore spaces
pore spacesare air !!!
Wells• Well - hole drilled into the zone of saturation
for extracting water
• Artesian Well – well drilled into a confined aquifer; rises under its own pressure
Cone of depression – lowering of the water table around a well due to large amounts of water being pumped out
Groundwater Overuse (cont’d)
• Ground subsidence (sinking) can occur if water is used faster than it is replenished– Creates depressions or
sinkholes
Sources of Groundwater Contamination
• Sewage from septic tanks, farm wastes, inadequate or broken sewers
• Fertilizers and pesticides from agriculture
• Residential runoff
• Highway salts
• Chemical and industrial materials that leak from pipelines, storage tanks, landfills, or holding tanks
• Saltwater in coastal areas
• Minerals and nutrients from dissolved rock and other natural materials
Types of Groundwater Pollution
• Point Source Pollution – contaminants have an identifiable source– Smokestacks, car
tailpipe
• Nonpoint Source Pollution – contaminant source cannot be found– Several farmlands in the
same area
Contaminant Spreading• Flow downhill – contaminants leaked into the
ground at the top of a hill will flow downhill • Rainwater runoff – runs through the
contaminant, absorbs it, and transfers it to another area
Groundwater Cleaning• Infiltration/
Percolation - if water travels slowly through permeable sediment, the water is purified
River Basins
• the land surface that drains surface water into one large river which takes the water to the ocean
River Basins (cont’d)
• Watersheds (river basins) separated from each other by areas of higher elevation (divides).
• Tributaries - small streams branching from larger streams and rivers
North Carolina’s River Basins
• There are 17 river basins in North Carolina• Four of these river basins are found only in NC• The Hiwassee, Little Tennessee, French Broad, Watauga, and New
River Basins empty into the Mississippi River while all the others empty into the Atlantic Ocean.
Catawba River Basin• In 2006, over 1.7
million people lived within the Catawba River Basin
• Includes 15.6% of North Carolina’s population
• Covers 6.24% of NC’s land
• 8th largest river basin in NC
Assignment• River Basin Posters• Include:• Size of basin• Miles of streams/rivers• What part of NC • Draw a plant or animal • Describe a water quality issue• Explain or propose a solution• A unique geological or water feature• Draw you and your partner doing one of the recreational
activities
Wetlands
Land that is covered by water all or part of the year.
Includes swamps, marshes and bogs
Why Wetlands are Important
• Provide flood protection during storms
• Filter pollution & urban runoff
• Habitat for many animals
Types of WetlandsSwamp
Mostly trees & bushesMarsh
Tall grasses, some trees & bushesCarolina Bays
Unique to East CoastOval-shaped lakes that often fill with plants & sediment
January 2002
Headwater Swamp
January 2002
Swamp Forest
January 2002
Hard Wood Flat
Wet Pine Flat
January 2002
Tidal Salt Marsh
Disappearing Wetlands
• Drained for development– New homes, roads and schools– Laws now prevent the
destruction of wetlands– Developers must create new
wetlands if they destroy old ones
“In nature there are no rewards or punishments, only consequences”