River Transportation and Deposition

Sec. 13.2 Page 121-122 Load Dissolved load Suspended load Bed load Competency Capacity Deposition

A. Zone of Erosion C. Zone of Deposition V-shaped B. Zone of Transport Headwaters V-shaped steep gradient Down-cutting/vertical erosion Rapids & waterfalls Boulders Friction slows flow C. Zone of Deposition Mouth of river depositing sediment in deltas U-shaped, wide, smooth channel low gradient, flood plain, levees Low friction so high velocity, high discharge B. Zone of Transport Asymmetrical channels Meanders Lateral erosion Cut banks River cliffs

Dissolved (in solution) load composed of… Suspended load made up of… Bed load made up of….. Salt, calcium ions Silt, clay and fine sand Pebbles, cobbles, boulders Dissolved: slat, calcium ions, Suspended: silt, clay fine sand, Bed load: pebbles, rocks, boulders ES1303 http://www.classzone.com/books/earth_science/terc/content/visualizations/es1303/es1303page01.cfm

How will each material be transported How will each material be transported? bed load, suspension or as dissolved load? Clay Boulders Calcium ions Pebbles Silt Coarse Sand Magnesium ions Fine Sand Suspension Bed load Solution Bed load* Suspension* suspension * Depends upon the velocity of the river.

Interpreting Graphs page 297 1. What particle stays in suspension at the slowest stream speed? 2. What is the minimum speed needed to carry a boulder in suspension? Name all the particles that would be in suspension in a stream moving at 100 cm/sec. 1. Clay 2. 300 cm/s 3. clay, silt, sand, pebbles 4. larger diameter – higher the velocity needed to keep it in suspension 4. Describe in words the relationship between particle diameter and the velocity of stream flow needed to keep the particle in suspension.

Competency The maximum SIZE of particles that a stream can transport The higher velocity of the water, the greater the competency http://www.youtube.com/watch?v=guBo0FQhjaM

Capacity The maximum AMOUNT of load a stream can carry The more discharge, the greater the capacity Sediment laden stream in Madagascar

As the water reaches the mouth of the river, its velocity slows and it loses energy. It sorts and deposits its load. At what location would you find each material to be DEPOSITED? Clay Calcium ions Pebbles Silt Coarse Sand Magnesium ions Fine Sand D A A-B C-D

Deposition When a stream velocity decreases (near the mouth) the river loses ENERGY and can no longer carry material. (competency) It DEPOSITS (dumps) sediment LARGEST material is sorted and deposited first. Eventually forming sedimentary rock. dunes Alluvial fans deltas http://www.classzone.com/books/earth_science/terc/content/visualizations/es0604/es0604page01.cfm?chapter_no=visualization

Mississippi River flows into the Gulf of Mexico, slows down and deposits sediment into the gulf.

A delta is formed where the river slows and deposits sediment into a body of water. Many distributaries branching out from the main river.