Earth Sciences 1022A/B Lecture 15: Earth Science Lecture March 8 2016

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1022A/B
• Professor: Stephen R Hicock

Document Summary

97% of the earth"s water is stored in the oceans, evaporated and then precipitated on land: some soaks in. Infiltration: some flows over land as streams. Runoff: some evaporates back into the atmosphere and is transpired by plants, some is stored in glaciers, most returns to the oceans by streams. Streams erode, transports according to velocity and channel shapes: gradient. Slope of stream channel over its length. Cross-sectional shape determines how much of the channel contacts water, slowing it down: rougher, more friction, discharge. Volume of water flowing through the stream"s cross-section per second. If discharge increases, stream usually gets wider, deeper and faster downstream. Is equal to the velocity x the depth x width. M/s x m x m: m3/s. Streams erode, transport, and deposit simultaneously over their lengths. By abrasion using particles in transport as cutting tools to scour channel walls. In circular eddies to cut potholes into the channel floor. 3 types of sediments load: dissolved.