FRESHWATER
COULTER
RIVER SYSTEMS: TRIBUTARIES
• RIVERS OFTEN BEGIN IN THE MOUNTAINS, WHERE RUNOFFS FROM MELTING SNOW FORMS
SMALL STREAMS.
• AS YOU FOLLOW A SINGLE STREAM YOU WILL NOTICE THAT IT JOINS ANOTHER.
• THESE STREAMS WILL EVENTUALLY FLOW INTO A SMALL RIVER WHICH WILL THEN JOIN A
LARGE RIVER.
• THESE STREAMS AND SMALLER RIVERS ARE CALLED TRIBUTARIES.
• A RIVER AND ALL ITS TRIBUTARIES TOGETHER MAKE UP A RIVER SYSTEM.
RIVER SYSTEMS: WATERSHED
• THE LAND AREA THAT SUPPLIES WATER TO A RIVER
SYSTEM IS CALLED A WATERSHED.
• WATERSHEDS ARE SOMETIMES KNOWN AS
DRAINAGE BASINS.
• MISSOURI AND OHIO RIVERS ARE LARGE YET FLOW
INTO THE MISSISSIPPI RIVER. SO LARGE RIVERS JOIN
ANOTHER RIVER SYSTEM.
• THE AREAS THEY DRAIN FROM BECOME PART OF THE
LARGEST RIVER’S WATERSHED.
RIVER SYSTEMS: DIVIDES
• ONE WATERSHED IS SEPARATED FROM
ANOTHER BY A RIDGE OF LAND CALLED A
DIVIDE.
• STREAMS ON EACH SIDE OF THE DIVIDE
FLOW IN DIFFERENT DIRECTIONS.
• CONTINENTAL DIVIDE: LONGEST DIVIDE IN
NORTH AMERICA FOLLOWS THE ROCKY
MOUNTAINS.
PONDS
• IN GENERAL PONDS ARE SMALLER AND SHALLOWER THEN LAKES. SUNLIGHT USUALLY REACHES TO THE
BOTTOMS OF ALL PARTS OF A POND.
• BODIES OF FRESH WATER.
• CONTAIN STILL WATER.
• HOW PONDS FORM:
• PONDS FORM WHEN WATER COLLECTS IN HOLLOW LOW-LYING AREAS OF LAND.
• SOME PONDS ARE SUPPLIED BY RAINFALL, MELTING SNOW AND ICE, RUNOFFS, RIVERS, OR GROUNDWATER.
• NOT ALL PONDS EXIST YEAR ROUND; SOME PONDS APPEAR IN SPRING WHEN RUNOFF AND MELTING SNOW COLLECT
IN LOW AREAS, THEN BY MIDSUMMER DRY UP DUE TO EVAPORATION.
LAKES
• LAKES ARE GENERALLY DEEPER AND BIGGER THAN PONDS. IN ADDITION, SUNLIGHT DOES NOT
REACH THE BOTTOM IN A DEEP LAKE, AS IT DOES IN A POND.
• NO PLANTS AND FEW ORGANISMS LIVE IN THE LAKES DEPTHS.
• BOTTOM OF A LAKE CONSISTS OF SAND, PEBBLES, OR ROCK, WHEREAS THE BOTTOM OF A
POND IS USUALLY COVERED WITH MUD OR ALGAE.
HOW LAKES FORM
• SOME, SUCH AS THE GREAT LAKES, FORMED IN
DEPRESSIONS CREATED BY ICE SHEETS THAT
MELTED AT THE END OF THE ICE AGE.
• OTHERS WERE CREATED BY MOVEMENT OF
EARTH’S CRUST.
• SUCH MOVEMENTS FORMED THE DEEP
VALLEYS IN CENTRAL AFRICA THAT LIE BELOW
LAKE TANGANYIKA AND LAKE VICTORIA.
HOW LAKES FORM CONT.
• OTHER LAKES ARE THE RESULT OF VOLCANOES.
• ERUPTIONS CAN CAUSE A FLOW OF LAVA OR MUD
THAT BLOCKS A RIVER AND FORMS A LAKE.
• SEA OF GALILEE WAS FORMED BY LAVA BLOCKING
JORDAN VALLEY
• SOME FORM IN THE EMPTY CRATERS OF LAKES.
• LAKES CAN ALSO BE FORMED BY BUILDING A DAM
(HELLO LAKE MEAD)
WETLAND
• WETLAND IS A LAND AREA THAT IS COVERED WITH WATER DURING PART OR ALL OF THE YEAR.
• HELP CONTROL FLOODS AND PROVIDE HABITATS.
• TYPES OF WETLANDS: THE THREE COMMON TYPES OF FRESHWATER WETLANDS ARE MARSHES,
SWAMPS, AND BOGS.
MARSHES
• MARSHES ARE USUALLY GRASSY AREAS
COVERED BY SHALLOW WATER OR
STREAMS.
SWAMPS
• LOOK MORE LIKE FLOODED FORESTS, WITH
TREES AND SHRUBS SPROUTING FROM THE
WATER.
• MANY ARE LOCATED IN WARM, HUMID
CLIMATES, WHERE TREES GROW QUICKLY.
BOGS
• ARE MORE COMMON IN COOLER
NORTHERN AREAS.
• THEY OFTEN FORM IN DEPRESSIONS LEFT BY
MELTING ICE SHEETS THOUSANDS OF YEARS
AGO.
• WATER IN BOGS TENDS TO BE ACIDIC, AND
MOSSES THRIVE IN THESE CONDITIONS.
COASTAL WETLANDS
• INCLUDE SALT MARSHES AND MANGROVE FORESTS.
Salt marsh
Mangrove forest
PROTECT THE WETLANDS!!
• BECAUSE OF THEIR SHELTERED WATERS AND RICH SUPPLY OF NUTRIENTS, WETLANDS PROVIDE
HABITATS FOR MANY LIVING THINGS.
• WETLANDS HELP POLLUTION CONTROL.
• WETLANDS ACT AS NATURAL WATER FILTERS. THEY ALSO HELP CONTROL FLOODS BY
ABSORBING EXTRA RUNOFF FROM HEAVY RAINS.
• WETLANDS ARE LIKE GIANT SPONGES, STORING WATER UNTIL IT GRADUALLY DRAINS OR
EVAPORATES.