the water cycle

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”