““Where’s Water?” Unit: Surface Water Where’s Water?” Unit: Surface Water

Rivers, Lakes, and PondsRivers, Lakes, and Ponds

River SystemsRiver Systems

The streams and smaller rivers that feed into a main river are called tributaries

Tributaries flow downward toward the main river, pulled by the force of gravity

A river and all its tributaries together make up a river system

River FeaturesRiver Features

Headwaters Tributaries Flood plain Oxbow lake Meander Mouth Delta Estuary

River FeaturesRiver FeaturesThe many small streams that come together

at the source (beginning) of a river are called its headwaters

The steep slope of the land causes the river to flow quickly

River FeaturesRiver FeaturesMeandersMeanders-looping curves in a riverMeanders can curve back on themselves.

The river may then cut a new, straight course, eventually leaving an oxbow lake

HorseshoeHorseshoeBendBend

of the Colorado River of the Colorado River near Page, AZnear Page, AZ

Ox Bow lake on MississippiOx Bow lake on Mississippi

River FeaturesRiver Features

The broad, flat valley through which a river flows is its flood plain

River FeaturesRiver FeaturesThe mouth of a river is where the river

flows into another body of waterA delta is created when the river slows

down and deposits the sediment it was carrying

Delta Formation

DEPOSITON OF MATERIAL BY THE RIVER WHEN IT ENTERS THE SEADEPOSITON OF MATERIAL BY THE RIVER WHEN IT ENTERS THE SEA

Mississippi Delta from Space Mississippi Delta from Space

MISSISSIPPI

WatershedsWatershedsThe land area that supplies water to a river

system is called a watershedWatersheds are sometimes known as

drainage basinsWe live in the Delaware River Watershed

DividesDivides

A ridge of land that separates one watershed from another is called a divide

Mountains are an example of a divide

DividesDivides

EstuariesEstuaries

An estuary is a coastal inlet or bay where fresh water from rivers mix with salty ocean water

Surface Water Part II: Surface Water Part II: Ponds and LakesPonds and Lakes

PondsPonds

Ponds are freshwaterPonds are shallowPonds form when

water collects in

low-lying areas of land

Plants grow at the bottom of ponds

LakesLakesLakes are freshwaterLakes are deepLakes form when

water collects in low-lying areas of land

Plants do not grow at the bottom of deep lakes

Lake Baikal, Russia

Lake FormationLake Formation

Lakes can be formed by natural processes or human efforts:

1. Volcanic lakes2. Glacier- made lakes3. Human- made lakes

A lake that stores water for human use is called a reservoir

Volcanic LakeVolcanic Lake

Glacier-Made LakesGlacier-Made Lakes

Human-Made LakesHuman-Made Lakes

Lakes Can ChangeLakes Can Change

Seasonal changes- water temperature at different depths changes during the year

Lake turnover-nutrients mixNutrients-substances such as

nitrogen and phosphorous that plants and algae grow

Lakes Can ChangeLakes Can Change

Long-term changesEutrophication-Algae and scum

forms on the surface of the water becomes so thick that it blocks out

sunlight and plants cannot carry out photosynthesis

Death of a body of fresh water

EutrophicationEutrophication

EutrophicationEutrophication

Ponds and LakesPonds and Lakes

SAME Freshwater Still, standing water Form when water

collects in hollows and low-lying areas of land

DIFFERENT Lakes are deeper Plants don’t grow at the

bottom of deep lakes Sunlight cannot reach

the bottom of a deep lake and photosynthesis cannot occur

Crater Lake and Lake Nyos LinksCrater Lake and Lake Nyos Links

http://en.wikipedia.org/wiki/Crater_lakehttp://news.bbc.co.uk/onthisday/hi/dates/sto

ries/august/21/newsid_3380000/3380803.stm