HTML University

Science Dept.

Geology and Soils GEO 100 Notes
Running Water - Streams

1. Hydrologic Cycle

2. Nature of Stream Flow
   1. Turbulent Flow

   2. Laminar Flow

3. Transportation
   1. Suspension

   2. Traction: Saltation, Rolling,. Sliding

   3. Solution

4. Hydraulic Factors
   1. Discharge

   2. Load
      1. suspended

      2. traction

      3. solution

   3. Gradient

   4. Channel Roughness and Shape

5. Stream Erosion
   1. Solution

   2. Suspension

   3. Abrasion of Bed and Banks
      1. Rounding of Stream Pebbles

      2. Valley Cutting and River Terraces

      3. Pot Holes

      4. Stream Piracy

6. Stream Deposition
   1. Meanders and Stream Bars

   2. Alluvial Fans
      1. Break in Slope

      2. Loss of Energy

      3. Deposition

   3. Floodplain Deposition and Natural Levees

   4. Deltas

7. Stream Stage (Valley Stage of Development)
   1. Youth
      1. Valley Will Have V-shape Cross Profile

      2. Little to No Flood Plain

      3. Water Falls, Rapids

      4. Little to No Meandering

      5. Steep Gradient

   2. Mature
      1. No Water Falls

      2. Meanders Present

      3. Flood Plains Exist

   3. Old Age
      1. Valley is Extremely Broad

      2. Large Flood Plains

      3. Valley Widths are Several Times Those of the Meader Belts

      4. Lakes, Swamps, Marshes on Floodplains

      5. Extensive Areas Are at or Near the Base Level of Erosion

      6. Very Low Gradient

      7. Many Oxbow Lakes, Cutoffs

8. Additional Notes
   1. The Geological Importance of Seasonal Peaks in Riverflow

   2. The Tendency of Streams to Widen and Deepen Their Valleys

   3. The Tendency of Streams to Extend Their Valleys Headward

   4. Stream Piracy

   5. Base Level, Long Profile

   6. Graded Stream

   7. Tendency of Stream Channels to Be Crooked

   8. Braided Streams

9. Development of the Landscape - Davis' Humid Cycle of Erosion an "Idealized Cycle"
   1. Youthful

   2. Mature

   3. Old age: peneplain

   4. Rejuvenation
      1. Stream Terraces

      2. Entrenched Meanders

   5. Reasons for Rejuvenation
      1. Global Sea Lowering

      2. Isostacy

      3. Glacial Rebouund

      4. Combination of Causes

10. Geologic Hazards of Running Water
    1. Floods
       1. Water

       2. Erosion

       3. Deposition

11. Flooding
    1. Storms
       1. Low Intensity Storms With Saturated Soils

       2. Intense Storms

    2. Melting of Snowpack

    3. Ice Jamming

12. Controls
    1. "Soft"
       1. Zoning

       2. Good Infiltration - decreases flood amounts

       3. Good Vegetation - decreases flood amounts

       4. Wetlands Protection - decreases flood amounts

    2. Structural
       1. Dike - floods previously unflooded land downstream

       2. Channelization - floods previously unflooded land downstream

       3. Dams - floods previously unflooded land upstream

13. Urbanization and Flooding
    1. Increase (Peak and Total) Runoff
       1. Runoff

       2. Erosion

       3. Deposition

    2. Lowers Water Quality

    3. Decreases Ground Water Recharge

14. Floods Are Natural
    1. Clean Out Debris in Channel

    2. Create Floodplains

    3. Energy and Nutrient Subsidy to Estuary

15. Floodplains and Floods
    1. Store Water

    2. Slow Erosion Rates by Slowing Velocity

    3. Decrease Amounts of Water Via Infiltration

16. Can Man Use a Floodplain?
    1. Its Natural Uses Are of Value

    2. Farming

    3. Recreation

    4. Wildlife

    5. Aquifer Recharge