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Created by Mr. Mleziva Rivers Review

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1 Created by Mr. Mleziva Rivers Review
Source: Source:

2 Also some Weathering and Erosion Review Type of Weathering?
Carbonation or Solution

3 1) stalactites Type of Rock? Type of Topography? 2) stalagmites Karst
Limestone

4 Type of Weathering? - Chemical - oxidation

5 Type of Weathering? Where is it common? Why? Physical - exfoliation Desert – high diurnal range in temp.

6 Evidence of? Aided by? Mass Wasting (The downslope movement of material under the influence of gravity) i.e. rock fall Freeze thaw action

7 Type of Mass Wasting? Resultant Landform terracettes Soil Creep

8 Type of Mass Wasting? A slump is a collapse structure formed in loose sediment by gravity sliding or by collapse under the weight of overlying younger sediments.

9 Difference between weathering and erosion?
Weathering – the breakdown of rock by chemical or physical means into smaller fragments Erosion – the transport of weathered rock fragments from the original site

10 condensation groundwater Source:

11 Source: http://www.epa.gov/glnpo/lakeont/lontdrain.gif
Drainage basin

12 levee Source:

13 Young Stage Interlocking Spurs
Source:

14 Old Stage oxbow lake Slip off slope - deposition
Source:

15 Name two fluvial landforms typically associated with location A.
waterfalls, rapids, potholes, V-shaped valleys with interlocking spurs Name two fluvial landforms typically associated with location B. levées, floodplains, meanders, oxbow lakes (cut-offs) deltas

16 Name and explain an inaccuracy in the diagram above.

17 In the upper course responses should note
that, in agreement with the model, the course is steep and there is a lot of erosion but that the river only flows quickly intermittently. There are lots of convexities in the profile (waterfalls, rapids) and bed roughness levels are high which effectively means that there is lots of water in contact with the bed, hence the average velocity is slow. In the middle course discharge levels are higher and there is still erosion (lateral and vertical) but in general velocity will increase as bed friction is reduced. The river does not start to slow down. In the lower course the river has high levels of discharge, but again the river does not slow. It becomes much more efficient as the channel becomes deeper, wider and there is less friction. There is still erosion here where meanders continually migrate, eroding laterally on the outside of bends.

18 Lagtime: the period between the maximum precipitation and peak discharge.
? List four factors that affect lagtime? - Soil and rock type, slope, size, and shape of the drainage basin, drainage density, type and amount of vegetation, land use, and water already in storage (antecedent precipitation)

19 Shania Twain Windsor, Ontario
P = Z Q = X R = Y Match each hydrograph to the correct basin. Shania Twain Windsor, Ontario

20 braiding

21 Drainage Pattern? Dendritic

22 Mississippi river delta = bird’s foot or digitate delta

23 The lowest point to which erosion by running water can take place is called ________________________. Base level Example of positive change in base level? Sea-level rises in relation to the land (or the land sinks in relation to the sea.) Decrease in gradient of the river; increase in deposition and potential flooding of coastal areas. A negative change in base level increases the potential energy of a river, enabling it to increase its erosive activity; in doing so, it upsets any possible graded long profile. This is known as ________________________. rejuvenation What can cause rejuvenation? - Isostatic rebound once the weight of a glacier has been removed - Uplift due to plate movement; tectonic forces

24 River terrace: remnant of a former floodplain, following vertical erosion caused by rejuvenation, has been left high and dry above the maximum level of present-day flooding; often excellent sites for locations of towns

25 Drainage Pattern? Radial

26 knickpoint

27 watershed

28 Drainage Pattern? trellis

29 What is significant about the water balance for this city?
A water surplus all year as the available precipitation always exceeds the potential evapotranspiration.

30 Name and describe three methods of transport in a river.
Name and describe three methods of erosion by a river other than vertical, headward, or lateral erosion. - corrasion / abrasion - attrition - hydraulic action - solution / corrosion: related to the chemical composition of the water; eg concentration of carbonic acid which dissolves materials

31 Aswan Dam, Egypt – vertical air photo

32 Aswan Dam, Egypt List four advantages List four disadvantages

33 Acid Rock drainage: lowering ph + leaching out heavy metals = threat to flora and fauna - a significant concern if 4% or greater content of sulfur in waste rock. Key Threat to Nearby streams and rivers?

34

35 List four ways that the urban environment alters the natural hydrologic cycle?

36 Examples of Poor River / Drainage Basin Management leading to increased runoff, erosion, and threat of flooding: “pod” Poor farming techniques i.e. ploughing against the contours Overgrazing Deforestation i.e. large clearcuts

37 Better Management: “prrb ddcp ”
Plough with the contours, terrace farming Ranchland management i.e. put animals in a pen Reforestation / afforestation / practice silviculture Build dikes Dam Dredge sediments and gravel from the river bed to increase carrying capacity Canals to channel water for irrigation and drinking water - Preserve wetlands

38 Arcuate delta eg The Nile Delta
Source:

39 1370 km To within +/- 100 km, how long is the Fraser River?
Fraser River Drainage Basin 1370 km

40 The effect on River Discharge?
- Significant Increase during rainfall The effect on Sediment Load? - Increase due to more soil erosion Source:

41 Final Jeopardy

42 A 1) Identify the feature at A. 2) Stage of the river?
3) Type of Erosion at A and dominates in this stage? A Source:

43 3) Vertical Erosion 2) Young Stage 1) Plunge Pool


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