FRESHWATER COULTER RIVER SYSTEMS TRIBUTARIES RIVERS OFTEN BEGIN

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.