Revision powerpoint for 3.1 Coastal Processes focusing on Muriwai Beach and Maori Bay by Takapuna Grammar Geography

1. MURIWAI REVISION
3.1

2. In this session:
• It will be more like a lecture because of time
• I suggest you listen and understand rather than trying to
make copious notes
• I will make the power point available on knowledge net
so you can look at it in more detail later.

3. This standard is titled:
Demonstrate understanding of
how interacting natural processes
shape a New Zealand
geographic environment

4. This standard is titled:
Shape is how it was made
and modified and how it is
being modified now
Demonstrate understanding of
how interacting natural processes
shape a New Zealand
geographic environment

5. This standard is titled:
This is plural so you need more
than one process
Demonstrate understanding of
how interacting natural processes
shape a New Zealand
geographic environment

6. This standard is titled:
Demonstrate understanding of
how interacting natural processes
shape a New Zealand
geographic environment
Your geographic environment is the South Muriwai
Coastal Environment (SMCE)from Maori Bay to
Okiritoto Stream (learn this)

7. Hence to score marks you
must:
• 1. Analyse not just describe (always give
depth)
• 2. Use 2 different processes in the paper
• 3. Mention South Muriwai throughout
answers

8. We will break up this revision
session into:
• 1. Going over content
• 2. How To answer Questions
• 3. What to expect with this exam.

9. Part 1: CONTENT

10. 3.1 CONTENT
• Demonstrate comprehensive understanding of how interacting
natural processes shape a New Zealand geographic environment
involves:
• • providing an insightful analysis of the interacting natural
processes and how they shape the environment
• • integrating comprehensive supporting case study evidence.
• An insightful analysis includes an analysis of the interaction
between the processes and

11. THE SIZE AND EXTENT OF THE
ENVIRONMENT
Okiritoto Stream
what is the
distance?
Maori Bay

12. ITS LOCATION
General: It is on the west
coast of the North Island
Specific: 40km NW of
Auckland CBD . It lies
between the Manukau and
Kaipara harbours at
36°49'00"S and 174°27'00"E

13. THE CHARACTERISTICS OF THE
SETTING
• These can be divided into the:
INPUTS
Elements
PROCESSES
Processes
OUTPUTS
Features
What the
‘things’ are
that make up
the
environment
The actions
that occur
between
elements
The result of
the
processes
Eg Wave
erosion
Eg a stack
Eg Sand

14. Lets look at these in detail: The Elements that
give it specific characteristics
WATER ELEMENTS
LAND ELEMENTS
AIR ELEMENTS
Waves- Average 1.5 m,
high energy due to
2,000km fetch over
Tasman
Relief – flat beach (0-5 degrees)
while headland up to 200m
Wind: Blows over
11knots 42% of time
from SW.
Currents – strong rips
Sediment - white is quartz and
feldspar (0.5mm diameter) and
black titano-magnetite
(0.25mm)
Geology: Headland of Manukau
Breccias while beach sandstone.
Vegetation: dune plants like
Spinifex and pingao, headland of
flax, Manuka and Pohutakawa.
Animals: 1,200 pairs of Gannets

15. Main Processes we study are:
HIGH SCALE
MIDDLE SCALE
SUB-PROCESS
WAVE ACTION
Wave Formation
Refraction
Reflection
Wave Transport and
deposition
Longshore drift
Wave Erosion
Hydraulic Action
Corrasion
Corrosion
Spray-splash action
Wind Transport
Saltation
(suspension and creep)
WIND ACTION
(AEOLIAN ACTION)
Wind deposition
NB: Any of these count as 2 different processes

16. Other processes you can
mention:
HIGH SCALE
LOWER SCALE
TECTONIC
Volcanism
Faulting
CLIMATOLOGICAL
Aerial weathering
BIOLOGICAL
Vegetation Growth
Biochemical weathering
Use these if answering about formation of features
(several processes) but avoid if asked to analyse ONE
process.

17. The Main Features and their
characteristics are:
FEATURE
CHARACTERISTICS
HEADLAND
400M long, cliffs 30m high and top of
headland 200m. Made of resistant
Manukau Breccias. Dense vegetation
on top of trees and flax.
STACK
30m high and 20m from headland.
More eroded landward side. Gannet
colony on top. Manukau Breccias.
BEACH
Foreshore 150m wide with small
berm, flat 1-5 degrees only . Black
ironsand accumulates at top.
DUNES
Av 8m, white sand dominates,
stablised by fast growing dune plants
with good root system. Plants
adapted to salt and wind.
PICTURE

18. Where These Features are Found:

19. These are all related:
ELEMENT ONE
PROCESS
FEATURE
ELEMENT TWO
WAVES
WAVE EROSION
GEOLOGY
STACK

20. Criteria 2: Natural processes that
operate
• A process is a series of actions.
• Therefore you must show this in your answer
• This happens first, then this and then this.
• Pick high scale processes as you have more to
talk about. Remember to analyse.

21. WAVE ACTION - due to strong winds, long fetch
• 1. High Energy Waves form WHY
• 2. Approach Muriwai environment from SW – WHY due to prevailing winds
• 3.Waves bend or refract off the headland WHY waves slow down here first as
hit shallow water.
• 4. Energy or orthogonals concentrates on headland WHY due to the refraction
of waves
• 5. When hit the headland they erode HOW by hydraulic action of pressure
differences, corrosion or chemical weathering or corrasion or battered by
sediment in waves. Weak areas are attacked between high and low tide mark
forming crevasses that get bigger.
• 6. Notch develops that over time becomes a cave. As on 3 sides becomes an
arch and roof weakened HOW by gravity, vegetation growth and biochemical
weathering so collapses to form an isolated stack.

22. WIND ACTION
• 1. Strong winds blow on shore WHY prevailing winds in SW belt.
• 2. On beach they pick up sediment and move it in 3 ways
suspension, saltation or creep WHY depends on size. Most at Muriwai
saltated.
• 3. Moves to backshore in bouncing fashion WHY light enough to be carried
by wind but weight brings back to land.
• 4. At backshore continues until wind strength reduced and deposition
occurs instead. WHY usually occurs when reach an object or plants on
dunes. Sets up zone of zero wind velocity.
• 5. Over time dunes grow in size WHY As plants are buried shoots grow
upwards effecting zone of zero wind.

23. Criteria 3:The distribution and formation
of the natural features
• Distribution refers to where they occur.
• Why do dunes occur at back of beach and not on
the headland?
• Why does the stack occur at end of headland
and not back of beach?
• All the result of what the characteristics of the
features are like.

24. How Features are Formed
• Suggest do either the stack or dunes.
• Often asks for several processes involved in the formation of
the feature
• Stack result of : volcanism (caused resistant rock), Tectonics
(push above sea), Wave Erosion, aerial weathering and
biochemical weathering above high tide level.
• Dunes result of: Saltation, Aeolian deposition and Vegetation
Growth

26. Criteria 4: Spatial variations in the operation of
natural processes in the geographic environment
• What this means: Where a process happens most and
least.
• You must answer by saying where it dominates, happens
a lot, does not happen etc.
• This is due to differences in the elements as they are not
equally distributed in the environment. For Muriwai
break down into 3 sub areas of Muriwai
beach, Otakamiro Headland and Maori Bay.

27. MURIWAI BEACH
OTAKAMIRO HEADLAND
MAORI BAY
Wide flat area
Hilly
Flat beach but small and cliffs
at back
Wind onshore and
strong
Strong onshore wind
Winds confused by stack
Waves less energy as
orthogonals diverge
Waves strong as
orthogonals converge
Waves also confused by shape
Lots of loose
(unconsolidated)
sediment
No loose sediment only
solid rock
Loose sediment on beach but
more black sand
As wave erosion needs converging waves and hard rock happens most on
headland, a little at Maori Bay and only in storm conditions at Muriwai
Beach.
As saltation needs loose sediment and a wide flat area to operate this
occurs most at Muriwai beach, only a little at Maori Bay and not at all at
the headland.

29. Criteria 5: Temporal variations in the
operation of natural processes in the
geographic environment
• This is similar but over time. Processes do not occur
consistently but happen more at some times (when elements
required are favourable) compared to other times when are
sparse.
• In our case the best examples relate to summer versus winter.

30. SUMMER
WINTER
Highs dominate in Tasman
Depressions dominate in Tasman
Produce gentle spiller waves and
light breezes
Produce plunger waves and strong winds
often of storm condition.
Wave Action: Gentle spiller waves have greater swash than backwash, deposit
more than remove so build up beach profile.
Strong plunger waves have stronger backwash than swash so remove more
sediment than deposit leaving flatter profile. Taken to sand bar.
Wind Action: Gentle breezes in summer mean that saltation is not as common.
As a result the dunes are not replenished as much as in storm conditions in
winter.

32. • Wave Erosion
• 1. Building of solid wall in 80’s. No good as energy directed
downwards and wall collapsed.
• 2. Building of gabion cage in 90’s. Better as wave energy dissipates
through spaces between rocks. However in storms so much water
so a lot reflected off wall and onto the southern part of beach
causing excessive erosion. Had outcome of a flatter beach at
this end.
• 3. Rip Rap in 2005 means more spaces for storms and extra
protection. Outcome is that wave erosion is reduced.
• All actions deliberate and aim to protect access to Fisherman’s rock.
Now successful

33. • Wind Action
• 1. Some actions accidental such as building surf club tower. Sets up
zone of zero wind velocity and sand builds up against wall as wind
deposition increased. This caused it to be buried. Had to be moved
backwards 3 times.
• 2. Also effects of farming in 1880’s and dune surfing in 1980’s.
Remove protective vegetation cover so cannot stop saltation from
increasing.
• 3. Deliberate sand stabilisation schemes of 1931 and 1969 helped
to increase wind deposition by planting first marram grass and then
spinifex on dunes. First one too successful as dense vegetation so
dunes collapsed. Second better allowing some saltation to
continue. Outcome is stable dunes.

34. End of content
• Do you feel you understand this
better?
• Get up and have a 1 min break.

35. Part B: How To Answer
questions
• They are asked in 3 ways:
• 1. An Essay (diagrams may be included)
• 2. A diagram only (one or a series of them)
• 3. A diagram for (a) with a written component
for (b)

36. Let us start with Essays

37. Rules for different grades:
• Be clear what the different grades are
awarded for
• There are 2 sorts of mark per question
• 1 refers to depth of answer
• 1 refers to use of specific information

38. Let’s look at depth of answer first:
• Analyse the operation of one process (forget environment
here)
• The waves come in and hit the headland
and cause erosion
• This gets an NA as does not analyse. How
is erosion caused?

39. • The waves come in and refract so that they
concentrate on the headland and erode it
where it is weaker
• This now would get an A as has some
explanation/ analysis in it

40. • The waves come in and slow down off the
headland first so that they refract or bend
which concentrates the energy of the
waves onto the headland. Sub-processes
of wave erosion such as hydraulic action
and corrosion then attack the rock where
it is weaker and break it down.
• This has some depth so gets a Merit.

41. To lift this further you need to give
technical understanding
• The wave velocity slows as it approaches the shoreline
due to the frictional drag caused when the wave hits the
bottom. This causes the wave to bend or refract and
concentrates the orthgonals or wave energy on the end
of the headland. Here processes such as hydraulic action
(pressure differentials when air is forced into
joints), corrasion (waves using sediment to batter the
rock) and corrosion (chemical breakdown of the minerals
in the rock by seawater) break down the resistant rock
between high and low water to form a notch.

42. Then you must add specific
information to this:
• First time it is linked to setting is equal to an A
• When 3 mentions made becomes an M
• When more than 3 used throughout the answer
becomes an E.

43. So if we take our Excellence
example it becomes:
• Waves at Muriwai have high energy due to the 2,000km
fetch across the Tasman sea and average 1 ½ m in height.
The wave velocity slows as it approaches the South
Muriwai shoreline due to the frictional drag caused when
the wave hits the bottom. This causes the wave to bend
or refract and concentrates the orthgonals or wave
energy on the end of Otakamiro headland. Here
processes such as hydraulic action (pressure differentials
when air is forced into joints), corrasion (waves using
sediment to batter the rock) and corrosion (chemical
breakdown of the minerals in the rock by seawater)
break down the resistant Manukau Breccia rock between
high and low water to form a notch.

44. What Are the other rules about
essays?
• 1. Read the question carefully and highlight key words
• 2. Do a rough plan on the planning page and keep to it.
• 3. It needs an introduction, body and conclusion
• 4. You must write in full sentences. Bullet points or note form
is only able to score a maximum of an A.
• 5. Use space as a guide to length needed. Aim to fill this.
• 6. Try to include at least one diagram even if rough and refer
to it in text.

45. Learn a few short cuts:
• Start with a standard paragraph that includes
your 3 specifics:
• South Muriwai beach is located 40km NW of
Auckland CBD and extends from Okiritoto stream
in the north to Maori Bay 5km south. (then
restate question)
• Specifics can also count in a map so include this.

46. What About Rules for
Diagrams
• It is important to establish if this is:
• 1. A stand alone diagram question
• 2. A diagram as part (a) with written part (b)
• 3. A diagram within an essay

49. Part 3 : What is this years exam
likely to look like?

50. Assessment Specifications
• Candidates will be provided with a choice of
TWO questions to answer.
• Candidates will be expected to answer ONE
question using both an annotated map or
diagram and a related written component.
• Both parts contribute toward the single grade
that will be awarded.

51. • Format of the assessment
• Candidates should use specific information and / or case
studies to illustrate their answers
•
• Equipment to bring
• Scientific calculator, coloured pencils, and a ruler.
• Candidates should use coloured pencils in their diagrams /
maps. Annotations on these diagrams / maps must be in pen.
Any work done in pencil will not be eligible for reconsideration.

52. How To Answer annotated
diagrams
• If asked to draw a map/diagram it must have its
FACKTS
• You must make it specific to your environment ie
Muriwai
• You must annotate it to show HOW something
happens.

54. Finally:
• Remember to include at least 5 statistics in your answer
• Make it focus on Muriwai.
• Read the question twice and underline important words.
• GOOD LUCK FROM US ALL!!!