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The hydrologic cycle

The hydrologic cycle. Running water. Streamflow Two types of flow determined primarily by velocity Laminar flow Turbulent flow Factors that determine velocity Gradient , or slope Channel characteristics including shape, size, and roughness. Running Water. Streamflow

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The hydrologic cycle

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  1. The hydrologic cycle

  2. Running water • Streamflow • Two types of flow determined primarily by velocity • Laminar flow • Turbulentflow • Factors that determine velocity • Gradient, or slope • Channel characteristics including shape, size, and roughness

  3. Running Water • Streamflow • Factors that determine velocity • Discharge – the volume of water moving past a given point in a certain amount of time • Changes from upstream to downstream • Profile • Cross-sectional view of a stream • Viewed from the head (headwaters or source) to the mouth of a stream

  4. Running water • Changes from upstream to downstream • Profile • Profile is a smooth curve • Gradient decreases downstream • Velocity • Discharge • Channel size

  5. Longitudinal profile of a stream

  6. Section of a stream

  7. Running water • Stream erosion • Lifting loosely consolidated particles by • Abrasion • Dissolution • Stronger currents lift particles more effectively

  8. Active erosion by a stream

  9. Running water • Transport of sediment by streams • Transported material is called the stream’s load • Types of load • Dissolved load • Suspended load • Bed load • Capacity – the maximum load a stream can transport

  10. Stream Load

  11. Skawa River, Poland, flood 2001

  12. Running water • Deposition of sediment by a stream • Caused by a decrease in velocity • Competence is reduced • Sediment begins to drop out • Stream sediments • Generally well sorted • Stream sediments are known as alluvium

  13. Running water • Deposition of sediment by a stream • Channel deposits • Deltas • Floodplain deposits • Natural levees – form parallel to the stream channel by successive floods over many years

  14. Formation of natural levees by repeated flooding

  15. The Nile and Mississippi Rivers deltas

  16. Natural Levees Sacramento River Levee

  17. NOAA Katrina NOLA 17th Street breach Aug 31 2005

  18. Running water • Stream valleys • Features of wide valleys often include • Floodplains • Erosional floodplains • Depositional floodplains • Meanders • Cut bank

  19. Erosion and deposition along a meandering stream

  20. A meander loop on the Colorado River

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