Headwaters • Beginning of a stream; high elevation.
Watershed • Land from which water runs off into a stream.
Tributary • Feeder stream that flows into a main stream.
Divide • Elevated region that separates 2 watersheds.
Floodplain • Area that may be covered with water during a flood.
Meander - E • Wide curve in a stream channel.
Cut Bank - E • The area of active erosion on the OUTSIDE of a meander.
Point Bar - D • A crescent-shaped accumulation of sand and gravel deposited on the INSIDE of a meander.
Oxbow • Water remaining in an isolated meander in a floodplain. • oxbow lake formation
Delta - D • Fan-shaped deposit of sediments at the mouth of a stream formed when rivers erode and transport sediments. When the river slows down, it deposits sediments.
Headward • Stream erodes away at the rock and soil at its headwaters in the opposite direction that it flows Niagara Falls
Downcutting • Deepening the channel of a stream by removing material from the stream's bed.
Meandering • Formed when the moving water in a river erodes the outer banks and widens its valley.
Bed Load • Particles in a flowing fluid (usually a river) that are transported along the bed
Suspended Load • Fine particles that are light enough to be carried in a stream without touching the stream bed.
Dissolved Load • Material, (especially ions from chemical weathering), that are carried in solution by a stream.
Gradient • Steepness of slope. • Change in elevation over a distance. • Elevation Drop Horizontal Distance • Feet/Mile • Example: • 50ft. Drop / 5 miles = 10ft./mile Gradient
How river systems change from young to mature! YOUNG MATURE • Wide Channels • Large floodplains • Lateral erosion • Gentle slopes • Meanders, oxbows • Fine sediment • Narrow channels • Small floodplains • Downcutting • Steep slopes • Rapids, waterfalls • Coarse sediment Life Cycle of a River Overview
YOUNG Stream • V – shaped valleys • Erodes away at bed (more than sides) • Waterfalls and Rapids are common. • Few Tributaries
OLD Rivers • Well established tributaries • Drains effectively • Carries LARGE amounts of water • Does not get deeper, (Erodes from Sides)
YOUNG Stream Mature Stream/River OLD River
FLOODS • Stream overflows channel • Causes • Weather events • Dams break • (+) Provides “fertilizer” for floodplain • (-) Most destructive of all geologic hazards
Describe human decisions that increase the risk of flooding. • Disturbing vegetation that uses water and returns it to the atmosphere before flooding occurs. • Building • Grazing animals • Farming practices like clear-cutting land • Cutting down forests
3 ways to prevent flooding Look over attached handout: • Dams • Artificial Levees • Channels
CANADA Nipigon Bay Jackfish Bay Thunder Bay Silver Bay St. Mary’s R. St. Lawrence R. Spanish R. St. Louis R. MICHIGAN Penetary Bay Sturgeon Bay WISCONSIN MICHIGAN Saginaw Bay NEW YORK Niagara Falls Saginaw R. System Grand R. MINNESOTA Niagara R. St. Clair R. Thames R. Buffalo R. Detroit R. Rouge R. Raisin R. Ashtabula R. PENNSYLVANIA IOWA Cuyahoga R. Maumee R. Rocky R. Black R. ILLINOIS INDIANA OHIO Great Lakes drainage basin Most polluted areas, according to the Great Lakes Water Quality Board “Hot spots” of toxic concentrations in water and sediments Eutrophic areas Fig. 19.7, p. 484
Trace the path(s) that 99% of water travels through the Great Lakes watershed. http://www.ofps.ucar.edu/gapp/networks/images/greatlakes_map.jpg