Physical Geology Chapter 13 Study Guide (Running Water) PDF

Physical Geology Chapter 13 Study Running Water Dos and Don’ts 1. You need to study for the exam. If you never needed to study in high school you will need to study for this exam. 2. Do not try to study at your house, apartment or in your dorm room. Find some pl...

Physical Geology Chapter 13 Study Running Water Dos and Don’ts 1. You need to study for the exam. If you never needed to study in high school you will need to study for this exam. 2. Do not try to study at your house, apartment or in your dorm room. Find some place quiet away from anyone you know. Friends tend to distract you from a quiet environment. 3. Turn off your phone. If you have just set it to silent – turn it off. You can catch up on texts, calls and email later. It will be there waiting for you. Put your phone in your backpack or purse. Get it out of sight. 4. Dedicate about an hour for each study session. It’s usually good to take a break after about an hour of study. If possible, do two study sessions a day. 5. College professors expect you to be able to dedicate three or four hours working on the material for every hour in class. College course loads look lighter than they really are. 6. Remember your goal. Your goal is to graduate or prepare to transfer to a four-year school. The best way to do this is to learn the material. Learn the material and the grade will follow. 7. Start about a week before the exam. You want to master about a chapter worth of material each day. Study materials available to you. In eCampus you have access to 1. the notes I lectured from 2. the slides I lectured from 3. the notes and drawings I projected on the screen 4. video lectures 5. you also have the textbook with mastering geology study aids 6. you also have the notes you took during the lecture. Study material: These are some of the things I consider important for the exam. This is not intended to be a complete list. You may encounter things that aren’t in this review. There will be things in this review that aren’t on the exam. Be certain to read the chapters, go over my notes, the slides, the class lecture notes and watch the video lectures. Do not rely on this as your only preparation for the exam. JLM (2024-02-05) Chapter 13 - Study Running Water Earth as a System: The Hydrologic Cycle Water moves through the hydrosphere’s different reservoirs by evaporating, condensing into clouds, and falling as precipitation. Once it reaches the ground surface, rain can either soak into the soil, evaporate, be returned to the atmosphere by plant transpiration, or run off over the surface. Running Water A stream’s flow velocity is influenced by channel gradient; size, shape, and roughness of the channel; and discharge. A cross-sectional view of a stream from head to mouth is a longitudinal profile. Usually, the gradient and roughness of the stream channel decrease going downstream, whereas the size of the channel, stream discharge, and flow velocity increase in the downstream direction. The land area that contributes water to a stream is its drainage basin. Drainage basins are separated by divides. Sediment is transported in a stream either in solution, suspended in the water, or rolling or saltating along the bottom of the stream. Stream Capacity is the total amount of sediment the stream can carry. Stream competence is the largest grain size a stream can move. Streams are efficient agents of sorting, meaning that they deposit similarly sized grains in the same area. Stream Channels Meanders are enhanced through erosion at the cut bank (outside edge of the meander) and deposition of sediment on the point bar (inside edge of the meander). The shape of the meander may grow more and more exaggerated until it loops back on itself. Once a cutoff is formed, the main current abandons the old meander loop, which becomes an oxbow lake. Streams erode downward until they approach base level, which is usually the level at which the stream enters another stream, a lake, or the ocean. A river flowing toward the sea (ultimate base level) may encounter several local base levels along its route. These could be lakes or resistant rock units that retard the downcutting of the stream. A graded stream has reached equilibrium with its base level and primarily works to transport sediment. Meanders are associated with a river that is eroding from side to side, whereas narrow canyons are associated with rivers that are vigorously downcutting. JLM (2024-02-05) The Work of Running Water Sediment is transported in a stream either in solution, suspended in the water, or rolling or saltating along the bottom of the stream. Compared to slow-moving rivers, fast-moving rivers can carry a greater total amount of sediment (capacity) and larger individual particles (competence). Flooding increases both capacity and competence, which is why rivers do most of their work during short-lived times of peak flow. Depositional Landforms A delta may form where a river deposits sediment in another water body at its mouth. The partitioning of streamflow into multiple distributaries spreads sediment in different directions. In the United States, the Mississippi River is an example of a major river with a dynamic delta system. Natural levees result from sediment deposited along the margins of a river channel by many years of successive floods. Because they slope gently away from the channel, the surrounding land is poorly drained, resulting in back swamps. Alluvial fans are fan-shaped deposits of alluvium that form where steep mountain fronts drop down into adjacent valleys. Floods & Flood Control Three main structural strategies exist for coping with floods: 1. construction of artificial levees to constrain streamflow to the channel, 2. alterations to make a stream channel’s flow more efficient, 3. and building of dams so that a sudden influx of water will be temporarily stored and released slowly to the river system. A nonstructural approach involves sound floodplain management. JLM (2024-02-05)