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Water. Water Distribution. Water use in the US in 2000. The Water Cycle. Transpiration (plants). Parts of a River. Collection. Transportation. Dispersal. Dendritic. Dendritic Pic - Yemen. Dendritic pattern Yemen. Radial. Rectangular. Limestone Bedrock:
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The Water Cycle Transpiration (plants)
Parts of a River Collection Transportation Dispersal
Dendritic Pic - Yemen Dendritic pattern Yemen
Rectangular Limestone Bedrock: Naturally fractures into squares & rectangles
Trellis Common in the Appalachians where rivers have cut through parallel ridgelines.
Delta Development Distributary Water coming down a river hits the ocean; gradient goes to zero Sediment is deposited; channel eventually fills River jump its banks and takes a new course Process repeats Very common in deltas
Mississippi Distributaries Mississippi River Delta
Mississippi Delta Left to its own devices, the Mississippi would now be flowing down the Atchafalaya Basin. Oil refineries line the Mississippi
Atchafalaya Mississippi Embankment Atchafalaya River
River Dynamics Rivers are complex systems influenced by number of things, which are: - discharge - velocity - gradient - sediment load - base level
Stream Discharge - amount of water passing by a given point during a specific time interval - measured in cubic meters/second
Oxbows II NE/SD border
Sediment Load - fine particles are moved in suspension, never touching the ground (suspended load) - silt & clay giving the water a muddy look - coarse particles are moved by traction along the stream bed, jumping along (bed load) - move by saltation: short leaps as a strong current picks them up and moves them a short distance. - 7-10% of the total sediment load, on average. - abrasion between particles causing them to wear, smoothing them and forming round pebbles and stones. - also wears away the stream channel along the sides and bottom of the channel. - dissolved materials are carried along in solution (dissolved load) - invisible chemical ions
Base Level The lowest elevation (depth) to which a river can erode its bed.
Stream Maturity Youthful Mature Old Age
Flooded River Levees occur when active deposition takes place along the banks of an older river when it is in a flood. Each time this happens the banks get higher forming a natural levee -- a barrier to future flooding.
Natural Levee Levees River channel
Urban Runoff More pavement = dramatically increased runoff rates
Levee If the river doesn’t flood, sediment is deposited on the river bed; causes water level to rise
Concrete Paving Smooth bottom = less friction = fast-moving water = less sediment deposition
Dams Siltation
Wastewater 15,000,000 people. All pavement. 50 inches of precipitation per year. Where does all the water go?
Urban sewer system Many urban sewer systems are outdated
Wilmington Wilmington, Delaware