1. Rivers

2. Why important?
Flooding has tormented civilization for a long time.

3. But… we continue to occupy low-lying regions adjacent to rivers.

4. Must understand ENTIRE river system… not just the region occupied by water on most days.

5. Drainage Basins: Where the water comes from.

6. Drainage Patterns

7. Basic Terminology:
Flood plain -area adjacent to river channel
Streams and Rivers
Runoff-portion of moving across the surface
Drainage basin -area drained by single stream
Slope-gradient of a stream (drop/unit of length)
Longitudinal profile -plot of elev. vs. length
Cross-section- profile across a stream valley
Plan view- two dimensions, map view
Base level- lowest level that a stream can erode its bed
Stream power = discharge X slope X unit weight of water

8. Measuring and Calculating Discharge
Continuity Equation
Discharge Q= V x A or V x W x D  blackboard example of conservation of discharge
Reach -river area under study

9. Channel Patterns Channel Patterns Braided Meandering Point bars
Riffles and pools
Oxbows
Anastomosing
Multiple channels
Gulf Coast (Fl, La)
Riverine environment--the river and adjacent floodplain

10. Channel Patterns – Braided Rivers
Nizina river, Alaska

11. Channel Patterns – Meandering River (forms & processes)

12. Avulsion – “permanent” change in a river’s course
1952
1988
McMurdo Basin,
Columbia River, B.C.

13. Sediments in Rivers Streams and Rivers Transport of rock cycle
Erosion and sediments
Total load
Suspended load
Bed load
Dissolved load
Competence-largest particle a stream can transport
Capacity-total load a stream can carry

14. Competence Diagram

15. Velocity/Shear Stress, Erosion, and Deposits
Alluvial fan-change in slope
Bajada -coalescing alluvial fans
Delta -form at the mouth of some rivers
Distributaries -streams that flow on deltas

16. Effects of Land Use Change
Change in stream profiles
Development
Dam construction
Modification of Continuity Equation
Q = C x i x A (C = Coefficient of infiltration; i =intensity of rainfall; A-area)

17. Florida Rivers

18. Florida Rivers