Lecture 17 - Liquid Water in the Landscape

Question 1

Define Catchment Area

Answer 1

-The area within a watershed
-All rain falling here will end up in the main river channel

Question 2

Define Interfluve

Answer 2

-A narrow, elongated, plateau-like landform between two valleys in the same drainage basin/ catchment area

Question 3

Define Main Channel

Answer 3

-The biggest river in the catchment area

Question 4

Define Tributary

Answer 4

-A stream ending in another larger stream/ river

Question 5

Define Infiltration

Answer 5

-The process by which water passes from the surface to subsurface
-In soil-mantled hillslopes rain drops on the landscape and droplets fill the voids within the soil particles

Question 6

Define Porosity

Answer 6

-Ratio between the volume of material and volume of voids
-Voids either filled with air or water (when all are filled with water, the soil is saturated)

Question 7

How is Groundwater arranged?

Answer 7

-Top = porous rock which is not saturated with water
-Middle = porous rock saturated with groundwater
-Bottom = impermeable rock

Question 8

What is Strathler’s Order?

Answer 8

-Classifying channels according to their position in larger river systems
-Headwaters are assigned an order of 1, and where two of these meet the stream is given an order of 2 and so on

Question 9

What is Horton’s First Law?

Answer 9

-In a catchment area the ratio of streams of a certain order and number of streams of a successive order is roughly constant (Bifurcation value)
-If this is plotted on a log scale (number of streams and stream order) and the line is straight, the catchment is in equilibrium

Question 10

Why is the Bifurcation Value Important?

Answer 10

-Bifurcation value gives us information about the shape of the basin
-The higher the value, the more elongated it is with low order rivers and a higher likelihood of flooding