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 marshMangrove 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.