Created by Mr. Mleziva Rivers Review Source: http://www.astroshow.com/west/river.jpg Source: http://www.astroshow.com/west/river.jpg

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

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

Type of Weathering? - Chemical - oxidation

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

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

Type of Mass Wasting? Resultant Landform terracettes Soil Creep

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.

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

condensation groundwater Source: http://www.uwsp.edu/geo/faculty/ritter/images/hydrosphere/hydrocyc.jpg

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

levee Source: http://snrs.unl.edu/amet351/naiman/break-in-levee.jpg

Young Stage Interlocking Spurs Source: http://ihouse.hkedcity.net/~hm1203/hydrosphere/interlocking-spur.jpg

Old Stage oxbow lake Slip off slope - deposition Source: http://www.uwsp.edu/geo/faculty/ritter/images/lithosphere/fluvial/oxbow_lake_large.jpg

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

Name and explain an inaccuracy in the diagram above.

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.

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)

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

braiding

Drainage Pattern? Dendritic

Mississippi river delta = bird’s foot or digitate delta

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

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

Drainage Pattern? Radial

knickpoint

watershed

Drainage Pattern? trellis

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

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

Aswan Dam, Egypt – vertical air photo

Aswan Dam, Egypt List four advantages List four disadvantages

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?

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

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

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

Arcuate delta eg The Nile Delta Source: http://www.athenapub.com/g04nilex.gif

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

The effect on River Discharge? - Significant Increase during rainfall The effect on Sediment Load? - Increase due to more soil erosion Source: http://www.pfc.forestry.ca/canforest/images/cwf26.jpg

Final Jeopardy

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: http://www.kadamsphoto.com/images/waterfalls/11.jpg

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