Hydrology and Fluvial Geomorphology

Question 1

open system

Answer 1

allows the movement of energy and matter across its boundaries

Question 2

precipitation

Answer 2

conversion and transfer of moisture in the atmsophere to the land
snow/hail/rain/frost/dew

Question 3

stores

Answer 3

vegetation
surface
soil moisture
groundwater
water channels

Question 4

characteristics that affect local hydrology

Answer 4

total amount of precipitation
intensity
type
geographical distribution
variability

Question 5

interception

Answer 5

interception loss
throughfall
stemflow

Question 6

evaporation

Answer 6

process by whcih a liquid or solid is changed into a gas

Question 7

factors affecting evaporation

Answer 7

albedo
temperature
wind speeds
humidity
vegetation cover

Question 8

transpiration

Answer 8

evaporation + transpiration

water vapour escapes from a living plant

Question 9

potential evapotranspiration

Answer 9

potential evapotranspiration is the water loss that would occur if there was an unlimited supply of water in the soil for use by the vegetation

Question 10

infiltration

Answer 10

water soaks into or is absorbed by soil

Question 11

infiltration capacity

Answer 11

the maximum rate at which rain can be absorbed by a soil in a given condition

Question 12

factors affecting infiltration

Answer 12

duration of rainfall
antecedent soil moisture
soil porosity
vegetation cover 
raindrop size
slope angle

Question 13

percolation

Answer 13

when water moves slowly downwards from the soil into the bedrock

Question 14

phreatic zone

Answer 14

permanently saturated zone within solid rocks and sediments is known as the phreatic zone

Question 15

aeration zone

Answer 15

seasonally wetted and dried zone

Question 16

baseflow

Answer 16

part of a rivers discharge provided by groundwater seeping into the river

Question 17

aquifers

Answer 17

permeable rocks (ie. sandstone and limestone) that contain significant quantities of water

Question 18

flow of a river is influenced by

Answer 18

amount and nature of precipitation 
local rocks' porosity and permeability 
shape (morphology), slope and area of the drainage basin
amount and type of vegetation cover
amount and type of soil cover
climate

Question 19

flood hydrograph

Answer 19

shows how the discharge of a river varies over a short time

Question 20

time lag

Answer 20

time between the height of the storm and the maximum flow

Question 21

peak flow

Answer 21

maximum discharge of the river

Question 22

factors affecting storm hydrographs

Answer 22

precipitation type and intensity
temperature and evapotranspiration
antecedent moisture
drainage basin size and shape
drainage density
porosity and impermeability of rocks and soils
slopes
vegetation type
land use

Question 23

critical erosion velocity

Answer 23

lowest velocity at which grains of a given size can be moved

Question 24

competence

Answer 24

diameter of the largest particle that can be carried

Question 25

reasons for deposition

Answer 25

a shallowing of gradient which decreases velocity and energy decrease in the volume of water in the channel increase in the friction between water and channel

Question 26

abrasion (corrasion)

Answer 26

wearing away of the bed and bank by the load carried by the river depends on the concentration, hardness and energy of the impacting particles and the resistance of the bedrock

Question 27

attrition

Answer 27

wearing away of load carried by river | creates smaller, rounder particles

Question 28

hyrdraulic action

Answer 28

``` force of air and water on the sides of rivers and in cracks includes cavitation (force of air exploding) ```

Question 29

solution (corrosion)

Answer 29

removal of chemical ions | affected by bedrock, solute concentration, discharge and velocity

Question 30

factors affecting erosion

Answer 30

load velocity gradient geology (softer rocks easier to erode) pH (corrosion faster when water is more acidic) human impact (deforestation, dams and bridges increase rate of erosion)

Question 31

Manning's Equation

Answer 31

Q = (AR^2/3 x S^1/2) / n | if bed roughness increases, velocity and discharge decrease

Question 32

Flows (3)

Answer 32

Laminar Turbulent Helicoidal

Question 33

Laminar Flow

Answer 33

smooth, straight channel with a low velocity | water flows in sheets parallel to the channel bed

Question 34

Turbulent Flow

Answer 34

higher velocities and features such as meanders causes variations in pressure within the water associated with hydraulic action -> vertical turbulence may create potholes

Question 35

Helicoidal Flow

Answer 35

aka Horizontal turbulence | corkscrewing motion

Question 36

Sinuosity

Answer 36

length of a stream channel expressed as a ratio of the valley length

Question 37

Thalweg

Answer 37

line of maximum velocity

Question 38

Pools

Answer 38

Fine sediment deposited at low velocity by Eddies in turbulent water

Question 39

Riffles

Answer 39

Coarse sediment deposited at high velocity by Eddies in turbulent water

Question 40

Floatation

Answer 40

twigs and leaves

Question 41

Traction

Answer 41

rolling, discharge high, big objects ie rocks

Question 42

Saltation

Answer 42

bouncing, small sediment

Question 43

Suspension

Answer 43

suspended in the water

Question 44

Solution

Answer 44

dissolved in the water