Presentation on Stream Action Perspectives and Cycles

Course ppt on Stream Action

1. Presentation On Stream Action By__ SAIDA ISLAM SEJUTI Roll- 18103432 Reg. no- 6829 1 st Year, 2 nd Semester Department of Environmental Science and Engineering

2. Outline of the Presentation Concept of Stream Action Water on Earth, Running Water Drainage Basins, Drainage Patterns Factor Affecting Stream, Stream Erosion Floods, Lakes; the Life Cycle of Lakes

3. Concept of Stream Action Steam Action= Stream + Action Stream: A flow of water in a channel or bed, as a brook, rivulet,  or small river. Action: Activity, work, movement, effort and such more. Comprises– The activity or movement of the flowing water. There origin, cause ,effects, affects, way etc and so on. Great oceanic Stream Flow

4. Concept of Stream Action

5. Water on Earth Volume, Types & Location : Vapor

6. Larger Distribution: Water on Earth

7. Water State and Cycle: Water on Earth Glacier Liquid

8. Running Water The most powerful agent of erosion. Continents are eroded primarily by running water at an average rate of 1 inch every 750 years.

9. Can carry these weathered rock pieces in three different ways:  Solution: The smallest particles, minerals. Suspension: Sand, silt & clay Bed load: Large sand grains, pebbles, and boulders, are even heavier rock particles. they just get pushed along the bottom as the bed load of the river. Running Water

10. Rocks carried in running Water Changes— Abrasion is the grinding action; changes particles in smaller, smother or in rounded shapes over time. Running Water

11. Is a place where water collects and then flows into a conventional outlet like a bay or a river. Encompasses the surface water and the ground water.  Numerous river branches collect water from different sources and then flows into the mainstream Drainage Basins

12. Drainage Basins Main 3 types of Drainage Basins— Ocean Basins— The largests are(% of world’s land) Atlantic Ocean: 48.7% Arctic Ocean: 17% Pacific Ocean: 13% Indian Ocean: 13% Southern Ocean: 8%

13. River Basins— 5 largests are- (in M km2) Amazon -7 Congo -4 The Nile-3.4 Rio De La Plata -3.2 Mississippi -3 Drainage Basins

14. Endorheic Drainage Basins— Are inland basins that do not drain to an ocean. 18% drains to endorheic lakes or seas or sinks.   The largest of these are- Caspian Sea, Aral Sea, Okavango river etc Drainage Basins

15. Drainage Patterns Created by stream erosion over time. Reveals characteristics of the kind of rocks and geologic structures. Formed by the streams, rivers, and lakes in a particular drainage basin. Governed by the topography of the land, whether a particular region. Dominated by hard or soft rocks, and the gradient of the land. Some common Patterns are-- Dendritic (Most common) Develops-- areas where the rock (or unconsolidated material) beneath the stream has no particular fabric or structure . Radial Volcanoes usually display excellent radial drainage. commonly develops are domes and laccoliths.  Trellis Typically develop where sedimentary rocks have been folded or tilted  Rectangular Develop in areas that have very little topography and a system of bedding planes, fractures, or faults   Parallel   Develops in regions of parallel, elongate landforms like outcropping resistant rock bands. 

16. Factor Affecting Stream Factors Affecting Velocity: Gradient (Slope)- Stream Profile Steeper gradients promote higher velocities. Head waters(Steeper) & Base levels Channel Characteristics Shape, Size & Roughness(materials) etc. Discharge (Volumetric Measure of Flow) Q=VA (average velocity x cross sectional area)

17. Factors Affecting Volume : 1- Weather or Climate 2- Seasonal Changes 3- Merging Tributaries 4- Human Impacts etc. Factor Affecting Stream

18. Stream Erosion Stream water is a very important agent of erosion. It can erode rocks and soil. Dissolves minerals from rocks that causes Chemical erosions gradually. By great gravitational forces it creates smaller sediment particles, transports them & causes Physical erosions. It is also affected by--the velocity, or speed, of the water. 3main processes of Stream Erosions are— # Solution, # Suspension & # Bed Load The river Erosion of the Grand Canyon.

19. Hydraulic Action Causes of Stream Erosions- Hydraulic Action: When the velocity of the water and steepness of the land is greater and also when the bottom of the water’s surface is rough. Abrasion: Happens by the friction from the  constantlymoving rock fragments, sediment, and gravel in the water. Attrition: Typically happens on upstream, when the velocity of the river is higher. Helps the sediment to be carried faster.  Solution: Some rocks can be broken down by the slightly Acidic water in a river or stream Stream Erosion

20. Extreme Flood state in Japan Causes– # Rains # River overflow # Strong winds in coastal areas # Dam breaking # Ice and snow-melts etc Floods

21. Types (mainly 2)— Flash Flood: Flash flood is a rapid flooding of geomorphic low lying areas: washes, rivers, dry lakes & basins. & Costal Flood: Coastal flooding occurs when normally dry, low- lying land is flooded by sea water . Floods

22. Lakes Is a body of water that is surrounded by land.   Vary greatly in size, shape, origin, waters type etc. Some most common types are-- #Tectonic, # Volcanic, #Glacial, #River, #Wind-made, #Man-made lakes etc. Water sources-   snow, melting ice, streams, and groundwater. Most lakes contain  freshwater.   Largest lake— Caspian (370,000+ s km) Deepest lake-- Lake Baikal (2 km) Highest Lake-- Lake Titicaca (3,810 m MSL) Lowest Lake-- Dead Sea (395 m below SL ) Caspian Lake’s View

23. Life Cycle of Lakes As per Scientists saying The Life Cycle of Lakes can be described under 3 inter-connected classes---

24. Life Cycle of Lakes

25. Conclusion Stream Action Undoubtedly includes all water bodies and actions related to them. So, all of these topics we discussed here are really a tiny part of them. But though in these slides we have got little or more the concepts of Water bodies of the world, there types of flow, drainage basins, pattern ,erosions caused by Streams, affecting factors of it, floods, lakes etc. We have also learned about 2 cycles here.

26. **Thank You**