Junior High Version
Version 6
Geological and Geomorphological History of the Region
The Gold Coast hinterland is on the Indo-Australian crustal plate which is moving 7cm north each year. The
Gold Coast hinterland was over a ‘hot spot’ between 24 to 23 million years ago. Hot spots are weaknesses in
the Earth’s crust that periodically force basaltic magma to the surface and erupt to form broad volcanoes.
Two large volcanoes were created at that time; the Focal Peak Volcano near Mount Barney, and the later
Tweed Volcano. The Tweed Volcano area stretched from Lismore (NSW) in the south to Tamborine (QLD) in
the north, from Mt Lindesay (QLD) in the west and fourteen kilometres out to sea.
The Tweed Volcano built up broad, shield shaped mountains (approximately 100km in diameter)
predominantly from great piles of highly fluid basalt lava that flowed long distances. Towards the end of
their activity, the magma deep below distilled into other lava types such as rhyolite. The viscous (sticky)
rhyolite erupted explosively and plugged vents on the northeastern flank of the shield volcano. The rhyolite
flows covered a much more limited area than the basalt flows. Some rhyolite magma cooled as large bodies
just below the surface such as Egg Rock and Pages Pinacles.
The central summit of the Tweed Volcano was located over the present Mount Warning and is estimated to
have reached about 2000 m above sea level. After the Tweed Volcano became extinct 10 million years ago,
the high mountain attracted heavy rainfall. The igneous rock gradually weathered to form rich soils
supporting thick rainforests and many streams flowed from the peak. Gradually the streams cut deep gorges
and as erosion progressed - the valleys widened.
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1
2
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Figure 1. Progressive Erosion of the Tweed Volcano (vertical scale exaggerated)
Erosion of the Tweed volcano has occurred due to the streams which radiate out from it: Tallebudgera Ck
and Currumbin Ck to the East, Nerang R, Coomera R and Canungra R to the North, and to the NW and West,
Albert R, Christmas Ck and Running Ck. Erosion is occurring at an average .03mm/year. (6.9km2 in 10
million years) The Tweed R has eroded the headwaters of the Nerang R and will continue to remove
material. Most erosion is in the valleys, while the ridges remain as flat plateaus, such as Mt Tamborine and
Beechmont. The Eastern streams are more active due to the higher rainfall there. The Tweed valley is an
erosion caldera, leaving only the remnant resistant plug of Mt Warning.
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History of Numinbah Valley
For thousands of years prior to the European settlement, the Aborigines freely roamed Nerang River Valley and the adjacent land. The
Kombumerries visited the Numinbah Valley and the high plateaux in summer searching for and gathering food and medicines. In winter they
moved closer to the coast, gathering fish and seafood. In Bushranger’s Cave, Aboriginal artifacts have been discovered by the Anthropology
Department of the University of Queensland and these have been estimated to be 10,000 years old. The original forests of the Numinbah Valley
were thick, lush rainforests or towering schlerophyll forests in the drier sections. The lowland sub-tropical rainforest was extremely rich in
diversity and these towering giant trees attracted the pioneering cedar getters in the 1860’s. Red Cedar, Hoop Pine, Silky Oak, Crow’s Ash, Black
Bean and Booyongs promised wealth to these early loggers. For the next 100 years, the wood cutter’s axe dominated the landscape as the valley
was stripped of its timber with the clearing often reaching high up into the hills. Five sawmills were kept busy supporting this industry.
Farming, mainly dairying, beef cattle, pig raising and banana plantations became the main industries as the land was cleared. In recent times,
tourist visitation in the area has increased.
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Weeds inhibit growth of native vegetation and
provides little habitat, filtration, soil stabilisation
and clog waterways.
1. Match the description with the number
Contaminants from poor agricultural
practices build up in the waterways and
food web.
Riparian vegetation is retained in its
natural state for habitat, filtration and soil
stabilisation.
Vegetation on banks prevents bank
erosion and provides habitat.
No buffer of native vegetation to
protect the river from runoff from
agriculture.
Cattle is fenced from the
river to protect banks
and vegetation.
Slumping and land slides
result from native trees being
replaced with pasture and
weeds.
Responsible
farming
practices limit
use
of
fertilisers,
herbicides
and pesticides.
Water is heavily silted with
algal blooms and
contamination. Sensitive
native species struggle
to survive.
Water
has
healthy
levels of sediments,
contaminants
and
nutrients due to good
land management.
Forest is maintained or reestablished on steep
slopes which prevents
slumping of soil.
Agricultural chemicals
are used heavily due to
land being degraded.
River banks are heavily eroded by livestock
accessing the river for drinking. Native
vegetation is trampled and becomes choked
by weeds.
Feral animals are not controlled
and threaten native species.
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Revegetation of cleared forest
rehabilitates degraded land and
increases biodiversity.
Cultivated land has a wide buffer
of native forest to prevent runoff.
Stop 2 Bochow Park
Riparian Vegetation Assessment - Stream Frontage and Banks
Category
Description
Excellent
Vegetation present with intact canopy.
Introduced species are absent or insignificant.
No evidence of outside interference.
Representative of natural vegetation in excellent
condition
Good
Native Vegetation present with canopy intact.
Minor disturbance with few introduced species.
Fair
Native vegetation is clearly disturbed or with
many introduced species. Soil is exposed or
disturbed by livestock or clearing.
Poor
Vegetation is cleared for grassland and
vegetation is mainly introduced. Bank is steep
and exposed.
Sketch Example
1. Use the tables above to assess this site.
Left Bank
Riparian Vegetation
2. Sketch the left and right bank riparian vegetation on the diagram below
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Right Bank
3. Explain the importance of riparian vegetation along waterways.
Stop 3 Forest Park
Forest Park is park is administered by Springbrook National Park and therefore has limited
facilities to maintain habitat for wildlife (e.g no bins, play equipment, or open grassed areas). In
contrast to Bochow Park, Forest Park has wood-fired BBQs and toilet facilities far away from the
river. Many people frequent this area on weekends and holidays. In recent times, the area has been
subject to weed invasion followed by eradication and revegetation activities.
4. Describe the differences in land management between Bochow park and forest park.
Would you expect an improvement in environmental outcomes such as biodiversity and water
quality?
Stop 4 Hinze Dam
Hinze Dam is located 15 km south-west of Nerang and is fed by the Nerang River and Little Nerang Creek.
Hinze Dam was designed for construction in three stages. The first stage was built in 1976. The second
stage in 1989 and increased capacity to 161,070 million litres. Stage Three is designed to increase the
capacity to 286,500 million litres by raising the dam wall 12.5 metres. The Hinze Dam, provides the water
requirements for the Gold Coast, one of the fastest growing population centres in Australia.
The water entering the dam is maintained at the best possible quality by placing the majority of the
catchment area within National Parks and State Forests. People are restricted from entering much of this
catchment area. Commercial businesses, factories and golf courses are prohibited from being built in the
catchment. Recreational boats are restricted to electric powered types. Hinze Dam is currently reported
to be one of the cleanest water supplies in Australia.
5. Why has Stage 3 been necessary to build?
.
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6. List the consequences that the raised dam water has had on the environment. What further
consequences will occur when the dam water recedes?
7. Throughout the catchment, you have identified sources of pollution which result in the reduction of
water quality in the Dam. What long term protective measures could be put in place to achieve the highest
possible water quality for the Gold Coast?
Notes/Field Sketch:
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Site: Bochow Park
Sensitivity
Number
Date:
School:
Feeding
Habit
Common Name
Tally
Sensitivity
Number
Predacious Diving Beetle
Carnivore
Tolerant
5
4
Very Tolerant
3
2
Red Water Mite
Predacious Diving Beetle Larvae
(Water Tiger)
Creeping Water Bug
Boatman
Backswimmer
Carnivore
Omnivore
Carnivore
(Parasite)
Herbivore /
Detritivore
Carnivore
Giant Water Bug
Carnivore
Leech
Snail
1
Carnivore
Pollution Index
Vertebrates
S
7
T
VT
5
1
Tadpole
Cox’s Gudgeon
Detritivore
Insectivore
Rainbow Fish
Omnivore
Gambusia
Omnivore
Excellent 15 +
Long Jawed Spider
Water Flea
Whirligig Beetle
Whirligig Beetle Larvae
Black Fly Larvae
Water Measurer
Damselfly Nymph
Dragonfly Nymph
Freshwater Yabby
Freshwater Shrimp
Water Strider
Freshwater Mussel
Water Scud
Mosquito Larvae
Water Scorpion
Scavenging Diving Beetle
Scavenging Diving Beetle Larvae
6
11 - 15
8
Detritivore
Herbivore
Carnivore
Carnivore
(Parasite)
Carnivore
Detritivore
Carnivore
Carnivore
Detritivore
Carnivore
Carnivore
Carnivore
Omnivore
Omnivore
Carnivore
Filter Feeder
Omnivore
Omnivore
Carnivore
Herbivore
Carnivore
Good
Herbivore
Riffle Beatle Adult
Riffle Beatle Larvae
Toebiter
This site provides an environment that only a few different types of
macroinvertebrates can live in.
This site provides a moderately healthy environment for many aquatic
macroinvertebrates.
This site provides a fairly healthy environment for many aquatic
macroinvertebrates to live in.
Stonefly Nymph
Fair 6 -10
9
This site is a very poor environment for aqatic macroinvertebrates.
Herbivore
Herbivore
Poor 0 - 5
Mayfly Nymph
Caddisfly Larvae
How healthy is this site’s environment?
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Taxa Richness
Sensitive
Invertebrates
POLLUTION INDEX – Add the sensitivity numbers
TAXA RICHNESS – How many different types of water bugs
10
0 – 40
Poor
41 -51
52 – 69
70 – 106
106 +
Fair
Good
Very Good
Excellent
WATER QUALITY MONITORING
Water quality refers to the level of cleanliness or purity of the water. There are many factors that can reduce the
quality of water. This reduction in quality may result in a change in the types and numbers of plants and/or the
suitability of water for drinking purposes.
Main Factors affecting Water Quality
Toxic Contaminants
Petroleum Products
Industrial Chemical
Insecticides
Herbicides
Poisons
Other Contaminants
Garbage
Plastics
Fishing Lines
Sewerage
Fertilizers
Testing of Water Quality
A variety of water quality parameters can be tested to find out information on the quality of water in a waterway.
These include:
Temperature
Recommended Levels
Temperature affects the amount of oxygen that can be dissolved in the water at any Ideal Temperature is
given time. The higher the temperature the less the DO the water can hold and the fewer Dependent on Climatic
the number of aquatic organisms that can survive. The rate at which plants can Conditions
photosynthesise is also affected by temperature as well as the metabolic rate which
aquatic animals can function and how much they are affected by disease, poison and
parasites.
Changes in water temperature can be caused by warm urban run-off from streets, car
parks, footpaths, clearing of riparian vegetation that shade watercourse, discharges
from industrial cooling plants and discharge of cool water from reservoirs.
Listen carefully to the information conveyed to you for conducting the tests and
record your results on the data sheets provided for two locations in the upper
catchment.
Phosphates
Nitrates and Phosphates
Many detergents contain phosphates. Sewage contains phosphates and nitrates. Good < 0.02 mg/L
Nitrates and phosphates are fertilizers and promote plant growth. These materials may Poor > 0.02 mg/L
enter waterways through sewage outfalls and run-off from farms, golf courses and
suburban areas. They may also occur naturally in small amounts in the environment.
Nitrates
The oversupply of nutrients may promote rapid growth of plant life and in particular,
algae. Initially this may increase oxygen levels. However, as plants die, bacteria begin Good < 0.25 mg/L
the decomposition process. These bacteria use large amounts of oxygen and can Poor > 0.25 mg/L
deplete the oxygen levels in a body of water. This can lead to fish kills and the death
of many other aquatic animals. Some algae produce toxic substances and these are
released when the plants decompose. This causes serious problems when the algae
occur in large numbers. Blue-green algae, for example, can result in a waterway
becoming toxic following a “bloom” of these aquatic organisms. High phosphate levels
can also result in eutrophication.
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Dissolved Oxygen
Recommended Levels
Dissolved Oxygen is a measure of the amount of oxygen carried in the water and is a
very good indicator of the general health of a waterway. Oxygen levels will be affected
by the level of stream turbulence (waterfalls and rapids), the depth of the water and the
comparative surface area in relation to depth. Temperature also has a large effect with
less oxygen able to be carried (dissolved) as temperate increases.
Large amounts of decomposing material (eg. from sewage or naturally occurring plant
debris) results in reduced oxygen levels as bacteria consume the oxygen with breaking
down of the organic material.
Dissolved Oxygen
Poor < 90%
Good 90 – 110%
Poor > 110%
Turbidity
Turbidity
Turbidity refers to the amount of suspended material in the water. This can be brought Good 2 - 25 NTU
about by soils and organise matters being washed off the land, turbulent water flow and High > 25 NTU
industrial or urban wastes. As water becomes increasingly turbulent, the penetration of
sunlight is reduced. This in turn will reduce plant growth which can lead to decreased
food sources and oxygen levels.
Salinity
Salinity
Salinity is the level of dissolved salts in the water. Salts occur naturally and originate Good 20 - 200 mg/L
in rocks and soils. An oversupply in a body of water can occur when water tables rise Poor > 200 mg/L
bringing salts to or near the surface. Other sources may include accessing underground
water supplies and industrial discharges. High salinity levels can reduce or eliminate
plant and animal life that is adapted to live in low salt (fresh) water environments. Of
course, high salinity levels in coastal areas can indicate the presence of sea water.
pH
pH
pH is the measure of the level of acidity or alkalinity of a substance. 7 is neutral and is Poor < 6.5
generally related to good water quality. An increase in salt, for example, will make Good 6.5 – 7.5
water more alkaline. Sea water has a pH of between 8 and 6.5. Water with a high Poor > 7.5
concentration of rotting organic material may be as low as 5 or 6.6 (see also effects of
nitrates and phosphates) Industrial pollutants and run-off from acid-sulphate soils can
have drastic effects on water pH which can result in large reductions in aquatic life and
major fish kills.
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Upland River Water Quality Parameter Data Sheet
Upland River Water Quality Parameter Data Sheet
Site: Bochow Park
Site:
Date: _________________________________________________
Date:_________________________________________________
Time: _________________________________________________
Time: ________________________________________________
Parameter
Temperature
Air
Temperature
Recommended Recorded
Implication
levels
Reading Interpretation
Parameter
Temperature
Seasonal
Seasonal
Air
Temperature
Seasonal
Water
Water
Nitrates
Recommended Recorded
Implication
levels
Reading Interpretation
Nitrates
Good < 0.25 mg/L
Poor > 0.25 mg/L
Seasonal
Good < 0.25 mg/L
Poor > 0.25 mg/L
Phosphates
Good < 0.02 mg/L
Poor > 0.02 mg/L
Phosphates
Good < 0.02 mg/L
Poor > 0.02 mg/L
Dissolved
Oxygen
Poor < 90%
Good
90 – 110%
Poor > 110%
Dissolved
Oxygen
Poor < 90%
Good
90 – 110%
Poor > 110%
Turbidity
Good 2 - 25 NTU
High > 25 NTU
Turbidity
Good 2 - 25 NTU
High > 25 NTU
Salinity
Good 20 - 200 mg/L
Poor > 200
mg/L
Salinity
Good 20 - 200 mg/L
Poor > 200
mg/L
pH
Poor
Good
Poor
pH
Poor
Good
Poor
< 6.5
6.5 – 7.5
> 7.5
Overall Assessment
< 6.5
6.5 – 7.5
> 7.5
Overall Assessment
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6
Tolerant
5
4
Very Tolerant
3
2
Caddisfly Larvae
Herbivore
Stonefly Nymph
Herbivore
Riffle Beatle Adult
Detritivore
Riffle Beatle Larvae
Herbivore
Toebiter
Carnivore
Red Water Mite
Carnivore
(Parasite)
Long Jawed Spider
Carnivore
Water Flea
Detritivore
Whirligig Beetle
Carnivore
Whirligig Beetle Larvae
Carnivore
Black Fly Larvae
Detritivore
Water Measurer
Carnivore
Damselfly Nymph
Carnivore
Dragonfly Nymph
Carnivore
Freshwater Yabby
Omnivore
Freshwater Shrimp
Omnivore
Water Strider
Carnivore
Freshwater Mussel
Filter Feeder
Water Scud
Omnivore
Mosquito Larvae
Omnivore
Water Scorpion
Carnivore
Scavenging Diving Beetle
Herbivore
Scavenging Diving Beetle Larvae
Carnivore
Predacious Diving Beetle
Carnivore
Predacious Diving Beetle Larvae
(Water Tiger)
Creeping Water Bug
Boatman
Leech
Snail
1
Carnivore
Carnivore
Omnivore
Carnivore
(Parasite)
Herbivore /
Detritivore
Backswimmer
Carnivore
Giant Water Bug
Carnivore
Pollution Index
Vertebrates
S
7
T
VT
5
1
Tadpole
Detritivore
Cox’s Gudgeon
Insectivore
Rainbow Fish
Omnivore
Gambusia
Omnivore
This site is a very poor environment for aqatic macroinvertebrates.
8
Herbivore
Poor 0 - 5
9
Mayfly Nymph
Taxa Richness
Sensitive
10
How healthy is this site’s environment?
Invertebrates
POLLUTION INDEX – Add the sensitivity numbers
TAXA RICHNESS – How many different types of water bugs
14
0 – 40
Poor
41 -51
52 – 69
Fair
Good
70 – 106
106 +
Very Good
Excellent
This site provides a fairly healthy environment for many aquatic macroinvertebrates to live in.
Sensitivity
Number
Excellent 15 +
Tally
11 - 15
Feeding
Habit
Common Name
Good
Sensitivity
Number
School:
This site provides an environment that only a few different types of macroinvertebrates can live
in.
This site provides a moderately healthy environment for many aquatic macroinvertebrates.
Date:
Fair 6 -10
Site: