UNIT 5 SEDIMENTATION IN A WATERSHED DEVELOPMENT
- 1. SOIL AND WATER CONSERVATION ENGINEERING S.Satheeshkumar AP/AGE Kongunadu College of Engineering and Technology Trichy
- 2. UNIT V SEDIMENTATION Sediment: Sources – Types of sediment load – Mechanics of sediment transport – Estimation of bed load – Sediment Graph. Reservoir sedimentation: Basics – Factors affecting sediment distribution pattern, Rates of reservoir sedimentation – Silt Detention Tanks – sediment control methods.
- 3. SEDIMENTATION Sedimentation is a process of settling down of the heavier particles present in a liquid mixture. For example, in a mixture of sand and water, sand settles down at the bottom. This is sedimentation.
- 4. SEDIMENT SOURCES Sediment sources can be divided into two broad categories: 1. Upland sediment sources 2. Channel sediment sources Upland sediment sources include various land-use and land-cover types: forest, cropland, pasture, construction sites, roads, etc.
- 5. WHAT IS SEDIMENT TRANSPORT MECHANISMS Main variables that describe the sediment transport mechanisms are the distribution of suspended sediment concentration, erosion-accumulation zones, bottom shear stress, and grain size distribution. It is difficult to obtain all these parameters from in situ measurements due to temporal and spatial heterogeneity.
- 6. TYPES OF SEDIMENT LOAD When particles are eroded and transported by wind, water, or ice, they become part of the transport medium's sediment load. There are three categories of load that may be transported by an erosional agent: Dissolved load Suspended load Bed load.
- 9. DISSOLVED LOAD Dissolved load is the portion of a stream's total sediment load that is carried in solution, especially ions from chemical weathering.
- 10. SUSPENDED LOAD Suspended load refers to that part of the total sediment transport which is maintained in suspension by turbulence in the flowing water for considerable periods of time without contact with the stream bed.
- 11. BED LOAD Bed load describes particles in a flowing fluid (usually water) that are transported along the stream bed. Bed load is complementary to suspended load and dissolved load.
- 12. Methods of Transporting Sediment Traction Saltation suspension solution.
- 13. Sediment Graph
- 16. Reservoir Sedimentation Reservoir sedimentation is the gradual accumulation of the incoming sediment load from a river. This accumulation is a serious problem in many parts of the world and has severe consequences for water management, flood control, and production of energy.
- 19. Factors that affect the sedimentation process The shape and size of particles The density of particles Water temperature Dissolved substances in the water Environmental effects Characteristics of the basin Slope of Stream Reservoir Length Size of Sediment Inflow Capacity Reservoir Operation Inflow Pattern of the Stream Vegetal Growth
- 21. A detention tank, also called a retention tank, is an artificial flow-control structure that is used to contain storm water and wastewater for a limited period of a time
- 22. Sediment control
- 27. Thank you