Transcript Slide 1
SURFACE WATER RIVERS, LAKES, & PONDS RIVERS River 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 Features Headwaters Tributaries Flood plain Oxbow lake Meander Mouth Delta River Features The 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 Features Meanders-looping curves in a river. Meanders can curve back on themselves. The river may then cut a new, straight course, eventually leaving an oxbow lake. Ox Bow lake on Mississippi Horseshoe Bend In the Colorado River near Page, AZ River Features The broad, flat valley through which a river flows is its flood plain. River Features The mouth of a river is where the river flows into another body of water. A 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 SEA Mississippi Delta from Space MISSISSIPPI Watersheds The land area that supplies water to a river system is called a watershed. Watersheds are sometimes known as drainage basins. We live in the Delaware River Watershed. Divides A ridge of land that separates one watershed from another is called a divide. Mountains are an example of a divide. Divides Estuaries An estuary is a coastal inlet or bay where fresh water from rivers mixes with salty water from oceans. Lakes & Ponds Ponds Ponds are freshwater. Ponds are shallow. Ponds form when water collects in low-lying areas of land. Plants grow at the bottom of ponds. Lakes Lakes are freshwater. Lakes are deep. Lakes form when water collects in low-lying areas of land. Plants do not grow at the bottom of deep lakes. Lake Formation Lakes can be formed by natural processes or human efforts: ① Volcanic lakes ② Glacier-made lakes ③ Human-made lakes A lake that stores water for human use is called a reservoir. Volcanic Lake Glacier-Made Lakes The Great Lakes Human-Made Lakes Lakes Can Change Short Term Changes: Seasonal changes-water temperature at different depths changes during the year. Lake turnover-nutrients mix. Nutrients-substances such as nitrogen and phosphorous that help plants and algae grow. Lakes Can Change Long-term changes: Eutrophication-Algae and scum forms on the surface of the water. It becomes so thick that it blocks out sunlight and plants cannot carry out photosynthesis. Death of a body of fresh water. Eutrophication Eutrophication Ponds 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 Types of Lakes http://en.wikipedia.org/wiki/Crater_lake http://news.bbc.co.uk/onthisday/hi/dates/stories/aug ust/21/newsid_3380000/3380803.stm www.unitedstreaming.com