Junior High Version. Version 6

Transcription

1 Junior High Version Version 6

2 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. 1

3 1 2 3 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. (6.9km 2 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. 2

4 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. 3

5 Weeds inhibit growth of native vegetation and provides little habitat, filtration, soil stabilisation and clog waterways. Contaminants from poor agricultural practices build up in the waterways and food web. No buffer of native vegetation to protect the river from runoff from agriculture. Slumping and land slides result from native trees being replaced with pasture and weeds. Water is heavily silted with algal blooms and contamination. Sensitive native species struggle to survive. 1. Match the description with the number Riparian vegetation is retained in its natural state for habitat, filtration and soil stabilisation. Vegetation on banks prevents bank erosion and provides habitat. Cattle is fenced from the river to protect banks and vegetation. Responsible farming practices limit use of fertilisers, herbicides and pesticides. Water has healthy levels of sediments, contaminants and nutrients due to good land management. 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. 4 Revegetation of cleared forest rehabilitates degraded land and increases biodiversity. Forest is maintained or reestablished on steep slopes which prevents slumping of soil. Cultivated land has a wide buffer of native forest to prevent runoff.

6 Stop 2 Bochow Park Riparian Vegetation Assessment - Stream Frontage and Banks Category Excellent Description Vegetation present with intact canopy. Introduced species are absent or insignificant. No evidence of outside interference. Representative of natural vegetation in excellent condition Sketch Example 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. 1. Use the tables above to assess this site. Left Bank Right Bank Riparian Vegetation 2. Sketch the left and right bank riparian vegetation on the diagram below 7

7 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 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?. 8

8 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: 9

9 Site: Bochow Park Date: School: Sensitivity Number Sensitive Tolerant Very Tolerant 10 Common Name Feeding Habit Invertebrates Mayfly Nymph Caddisfly Larvae 9 Stonefly Nymph Riffle Beatle Adult 8 Riffle Beatle Larvae Toebiter 6 Red Water Mite (Parasite) Long Jawed Spider Water Flea Whirligig Beetle 5 Whirligig Beetle Larvae Black Fly Larvae Water Measurer Damselfly Nymph Dragonfly Nymph 4 Freshwater Yabby Freshwater Shrimp Water Strider Freshwater Mussel Filter Feeder Water Scud Mosquito Larvae 3 Water Scorpion Scavenging Diving Beetle Scavenging Diving Beetle Larvae 2 1 Predacious Diving Beetle Predacious Diving Beetle Larvae (Water Tiger) Creeping Water Bug Boatman Leech Snail Backswimmer (Parasite) / Tally Sensitivity Number How healthy is this site s environment? Taxa Richness This site is a very poor environment for aqatic macroinvertebrates. Poor 0-5 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. Giant Water Bug Pollution Index Vertebrates 0 40 Poor S 7 Tadpole Fair Cox s Gudgeon Insectivore Good T 5 Rainbow Fish Very Good VT 1 Gambusia Excellent POLLUTION INDEX Add the sensitivity numbers Fair 6-10 Good Excellent 15 + TAXA RICHNESS How many different types of water bugs 10

10 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 Temperature affects the amount of oxygen that can be dissolved in the water at any given time. The higher the temperature the less the DO the water can hold and the fewer the number of aquatic organisms that can survive. The rate at which plants can 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. Nitrates and Phosphates Many detergents contain phosphates. Sewage contains phosphates and nitrates. Nitrates and phosphates are fertilizers and promote plant growth. These materials may 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. 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 the decomposition process. These bacteria use large amounts of oxygen and can 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. Recommended Levels Ideal Temperature is Dependent on Climatic Conditions Phosphates Good < 0.02 mg/l Poor > 0.02 mg/l Nitrates Good < 0.25 mg/l Poor > 0.25 mg/l 11

11 Dissolved Oxygen 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. Recommended Levels Dissolved Oxygen Poor < 90% Good % Poor > 110% Turbidity Turbidity refers to the amount of suspended material in the water. This can be brought about by soils and organise matters being washed off the land, turbulent water flow and 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 is the level of dissolved salts in the water. Salts occur naturally and originate in rocks and soils. An oversupply in a body of water can occur when water tables rise 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 is the measure of the level of acidity or alkalinity of a substance. 7 is neutral and is generally related to good water quality. An increase in salt, for example, will make water more alkaline. Sea water has a ph of between 8 and 6.5. Water with a high 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. Turbidity Good 2-25 NTU High > 25 NTU Salinity Good mg/l Poor > 200 mg/l ph Poor < 6.5 Good Poor >

12 Upland River Water Quality Parameter Data Sheet Upland River Water Quality Parameter Data Sheet Site: Bochow Park Date: Time: Site: Date: Time: Parameter Recommended levels Recorded Reading Implication Interpretation Parameter Recommended levels Recorded Reading Implication Interpretation Temperature Air Seasonal Temperature Air Seasonal Temperature Water Seasonal Temperature Water Seasonal Nitrates Good < 0.25 mg/l Poor > 0.25 mg/l Nitrates 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 % Poor > 110% Dissolved Oxygen Poor < 90% Good % Poor > 110% Turbidity Good 2-25 NTU High > 25 NTU Turbidity Good 2-25 NTU High > 25 NTU Salinity Good mg/l Poor > 200 mg/l Salinity Good mg/l Poor > 200 mg/l ph Poor < 6.5 Good Poor > 7.5 Overall Assessment ph Poor < 6.5 Good Poor > 7.5 Overall Assessment 13

13 Site: Date: School: Sensitivity Number Sensitive Tolerant Very Tolerant 10 Common Name Mayfly Nymph Caddisfly Larvae Feeding Habit Invertebrates 9 Stonefly Nymph S 7 Riffle Beatle Adult Riffle Beatle Larvae Toebiter Red Water Mite 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 Predacious Diving Beetle Predacious Diving Beetle Larvae (Water Tiger) Creeping Water Bug Boatman Leech Snail Backswimmer (Parasite) Filter Feeder (Parasite) / Tally Sensitivity Number How healthy is this site s environment? Taxa Richness This site is a very poor environment for aqatic macroinvertebrates. Poor 0-5 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. Giant Water Bug Pollution Index Fair 6-10 Good Vertebrates 0 40 Poor Tadpole Fair Cox s Gudgeon Insectivore Good T 5 Rainbow Fish Very Good VT 1 Gambusia Excellent POLLUTION INDEX Add the sensitivity numbers TAXA RICHNESS How many different types of water bugs 14 This site provides a fairly healthy environment for many aquatic macroinvertebrates to live in. Excellent 15 +