What is a delta?
A delta is a low-lying area where a river meets the sea. Often, the river divides into many tributary streams, forming a triangular-shaped area. The river deposits a large amount of sediment at its mouth, creating excellent soil for farming once the channel of the stream moves. One of the most famous deltas is where the Nile River meets the Mediterranean Sea. Other major deltas include the Mississippi River Delta in Louisiana, the Ganges River Delta in India, and the Yangtze Delta in China. The word delta comes from the Greek letter delta, referring to its triangular shape when written.
Where are some of the world’s largest freshwater marshes?
The Okavango Delta, in the southern African country of Botswana, forms a marsh that is 5,800 square miles (15,000 square km) in area. The Okavango River empties into the arid Kalahari Desert, forming the largest freshwater marsh in the world. The Everglades in Florida is another one of the world’s largest marshes, consisting of 2,185 square miles (5,659 square km). The water across this southern Florida marsh averages six inches (15 centimeters) in depth. The Everglades is an endangered ecosystem, threatened by excess drainage and the introduction of exotic plants.
What is a drainage basin?
The area that includes all of the tributaries for an individual stream or river is its drainage basin. For example, the drainage basin for the St. Lawrence River includes the area surrounding the Great Lakes. Rivers such as the Platte (which has its own drainage basin) flow into the Missouri, and the Missouri flows into the Mississippi. The combined area drained by the Platte, the Missouri, the Mississippi, and all other Mississippi River tributaries combined create the third-largest drainage basin in the world. The Amazon has the largest drainage basin of any river, while the Congo has the second largest.
What is a tributary?
Any stream that flows into another stream is a tributary. Most major rivers have hundreds of tributaries, which on a map look like branches of a tree. One classification system of rivers is based upon the number of tributaries a river has.
What is a watershed?
A watershed is the boundary between drainage basins. It is usually the crest of a mountain where water flows on either side into two different drainage basins.
What is a wadi?
Wadi is the Arabic word for a gully or other stream bed that is dry for most of the year. A wadi is a channel for streams that develop during the short rainy season. The channels of wadis were probably initially carved when the desert regions of today had more rainfall.
What is a meander?
Streams and rivers that have carved a flat floodplain commonly flow in curves known as meanders. These S-shaped curves vary by the size and flow of the river. The river flows faster on the outside curve of the meander and therefore continues to cut and create a larger curve.
What is an oxbow lake?
An oxbow lake is a crescent-shaped lake that is formed when the meander, or curve of a river, is cut off from the rest of the river during a flood, or when the curve of the meander becomes so large that the river begins flowing along a new path. The curve that remains becomes its own lake. These can commonly be seen along the Mississippi River system.
What is the world’s largest lake?
The Caspian Sea (which is really a lake) is the largest lake in the world. Until 11 million years ago, it was contiguous with the world ocean, so it is a saltwater lake. It is surrounded by Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan and is over 143,200 square miles (370,888 square km) in area. The second-largest lake in the world, Lake Superior in North America, is a mere 31,820 square miles (82,414 square km) in area and has more water than the other four neighboring Great Lakes combined. It is considered by many to be the largest freshwater lake in the world by surface area.
What is Africa’s largest lake?
Located in eastern Africa, Lake Victoria is Africa’s largest lake by area, with a surface area of approximately 26,828 square miles (69,485 square km). It is also the world’s second-largest freshwater lake, after Lake Superior. Lake Victoria is bordered by Uganda, Kenya, and Tanzania. The lake was named by British explorer John Hanning Speke, the first European to see the lake (in 1858), in honor of the reigning British queen. A map, drawn by Arab explorers in the late twelfth century C.E., describes the lake in great detail.
The Caspian Sea is actually a very large lake located in southern Russia, which also touches Turkmenistan and Kazakhstan.
Where is the highest lake in the world?
A yet-to-be-named small crater lake found atop Ojos del Salado (Spanish for “eyes of salty water”), a volcanic mountain on the border of Argentina and Chile, has an elevation of 20,965 feet (6,390 meters). Lake Titicaca, a lake sandwiched between Peru and Bolivia, is at 12,507 feet (3,812 meters) above sea level and is the highest navigable lake in the world, which means that you can go for a boat ride on this lake.
How do we know how much rain actually falls?
Agencies like the National Weather Service use very accurate devices that measure rainfall to the nearest one-hundredth of an inch. The devices, known as rain gauges or tipping-bucket gauges, collect rainwater, usually at a point unaffected by local buildings or trees that may interfere with the rain.
Where in the world does it rain the most each year?
Cherrapunji and the nearby town of Mawsynram, in India, near the border of Bangladesh, have the highest average rainfall per year in the world, averaging 467 inches (11,872 mm). They are in a subtropical climate zone and are impacted by monsoon rains that are heavy during the months of April through October. Mt. Waialeale, on the island of Kauai in Hawaii, receives an average of 452 inches (11,500 mm) of rain a year and often records some of the highest average precipitation in the world.
Where does it rain the least?
The Dry Valleys of Antarctica are considered to be among the driest places on Earth, with annual precipitation of less than .08 inches (2 mm). Because of its proximity to the Atacama Desert, Arica, Chile, is also considered by many to be one of the world’s driest places with an average annual rainfall of .03 inches (.761 mm). The northern Sudan’s Wadi Halfa (which is in the Sahara Desert) receives an average of less than .10 inches (2.54 mm) of rain per year. That’s hardly a drop at the bottom of a bucket.
How much water is in snow?
When about 10 inches (25 centimeters) of snow melts, it turns into about one inch (2.54 cm) of water. Snow has pockets of air between snowflakes when they are on the ground, so it takes ten times the amount of snow to make an equivalent amount of water.
How can I measure the amount of rain that falls where I live?
Any container with a flat bottom and flat sides can measure rainfall. The width of the top of the container must be the same as at the bottom of the container, but the diameter does not matter. It could be a device purchased for measuring precipitation or something as simple as a coffee can.
Do oceans get more rain than land?
The oceans receive about 77 percent of the world’s precipitation. The remaining 23 percent of precipitation falls on the continents. Some areas of the world receive far more precipitation than others. Some parts of equatorial South America, Africa, Southeast Asia, and nearby islands receive over 200 inches (500 centimeters) of rain a year, while some desert areas receive only a fraction of an inch of rain per year.
Where was the most snowfall ever recorded?