A waterfall is an area where water flows over a vertical drop or a series of steep drops in the course of a stream or river. Waterfalls occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls are formed in the upper course of a river in steep mountains; because of their landscape position, many waterfalls occur over bedrock fed by little contributing area, so may be ephemeral and flow only during rainstorms or significant snowmelt. The further downstream, the more perennial a waterfall can be. Waterfalls can have a wide range of depths; when the river courses over resistant bedrock, erosion happens and is dominated by impacts of water-borne sediment on the rock, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it may pluck material from the riverbed, if the bed is fractured or otherwise more erodible. Hydraulic jets and hydraulic jumps at the toe of a falls can generate large forces to erode the bed when forces are amplified by water-borne sediment.
Horseshoe-shaped falls focus the erosion to a central point enhancing riverbed change below a waterfalls. A process known as "potholing" involves local erosion of a deep hole in bedrock due to turbulent whirlpools spinning stones around on the bed, drilling it out. Sand and stones carried by the watercourse therefore increase erosion capacity; this causes the waterfall to recede upstream. Over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, it will carve deeper into the ridge above it; the rate of retreat for a waterfall can be as high as one-and-a-half metres per year. The rock stratum just below the more resistant shelf will be of a softer type, meaning that undercutting due to splashback will occur here to form a shallow cave-like formation known as a rock shelter under and behind the waterfall; the outcropping, more resistant cap rock will collapse under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are broken down into smaller boulders by attrition as they collide with each other, they erode the base of the waterfall by abrasion, creating a deep plunge pool in the gorge downstream.
Streams can become wider and shallower just above waterfalls due to flowing over the rock shelf, there is a deep area just below the waterfall because of the kinetic energy of the water hitting the bottom. However, a study of waterfalls systematics reported that waterfalls can be wider or narrower above or below a falls, so anything is possible given the right geological and hydrological setting. Waterfalls form in a rocky area due to erosion. After a long period of being formed, the water falling off the ledge will retreat, causing a horizontal pit parallel to the waterfall wall; as the pit grows deeper, the waterfall collapses to be replaced by a steeply sloping stretch of river bed. In addition to gradual processes such as erosion, earth movement caused by earthquakes or landslides or volcanoes can cause a differential in land heights which interfere with the natural course of a water flow, result in waterfalls. A river sometimes flows over a large step in the rocks. Waterfalls can occur along the edge of a glacial trough, where a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted.
The large waterfalls in Yosemite Valley are examples of this phenomenon, referred to as a hanging valley. Another reason hanging valleys may form is where two rivers join and one is flowing faster than the other. Waterfalls can be grouped into ten broad classes based on the average volume of water present on the fall using a logarithmic scale. Class 10 waterfalls include Paulo Afonso Falls and Khone Falls. Classes of other well-known waterfalls include Kaieteur Falls. Alexander von Humboldt "Father of Modern Geography" Humboldt was marking waterfalls on maps for river navigation purposes. Oscar von Engeln Published "Geomorphology: systematic and regional", this book had a whole chapter devoted to waterfalls, is one of the earliest examples of published works on waterfalls. R. W. Young Wrote "Waterfalls: form and process" this work made waterfalls a much more serious topic for research for modern Geoscientists. Ledge waterfall: Water descends vertically over a vertical cliff, maintaining partial contact with the bedrock.
Block/Sheet: Water descends from a wide stream or river. Classical: Ledge waterfalls where fall height is nearly equal to stream width, forming a vertical square shape. Curtain: Ledge waterfalls which descend over a height larger than the width of falling water stream. Plunge: Fast-moving water descends vertically, losing complete contact with the bedrock surface; the contact is lost due to horizontal velocity of the water before it falls. It always starts from a narrow stream. Punchbowl: Water descends in a constricted form and spreads out in a wider pool. Horsetail: Descending water maintains contact with bedrock most of the time. Slide: Water glides down maintaining continuous contact. Ribbon: Water descends over a long narrow strip. Chute: A large quantity of water forced through a narrow, vertical passage. Fan: Water spreads horizontally as
The Millstream Falls, a tiered plunge waterfall on The Millstream, is located in the UNESCO World Heritage–listed Wet Tropics in the Far North region of Queensland, Australia. The Millstream Falls are situated 15 kilometres southwest of Ravenshoe, on the Atherton Tableland and are accessible by road from the Kennedy Highway; the falls are protected within the Millstream Falls National Park. The falls comprise two sets of falls, Big Millstream Falls and Little Millstream Falls, both located on the same watercourse, situated 500 metres apart; the larger of the two falls is reputably the widest single-drop waterfall in Australia. List of waterfalls of Queensland "Tablelands Region: Visitor guide". Department of National Parks, Recreation and Racing. Government of Queensland. 5 November 2012. Archived from the original on 13 February 2014. "Millstream Falls. Australia's Widest waterfall when in full flood". Getaway Guide. Barrier Reef Australia. 2011.
The Blencoe Falls is a segmented waterfall on the Blencoe Creek, located in the Far North region of Queensland, Australia. The falls are situated in the Girringun National Park near Tully 2 kilometres north of a confluence with the Blencoe Creek and the Herbert River. From an elevation of 517 metres above sea level, the falls descend 320 metres in an initial drop of 90 metres and they cascade for another 230 metres to the base of the gorge; the falls can be reached by road from Mount Garnet on the Kennedy Highway. The Kirrama Range Road from Kennedy on the Bruce Highway provides access from the coast to the falls. Blencoe Falls lookout is 62 kilometres west of Kennedy; the traditional custodians of the land surrounding the Blencoe Falls are the Indigenous Australian Warungnu peoples, some of whom were driven over the ridges above Blencoe Falls to drown in the gorge. The second season of Survivor was filmed in an area close to the falls. List of waterfalls of Queensland "Blencoe Falls, Girringun National Park".
Department of National Parks, Recreation and Racing. Government of Queensland. 4 July 2012. Blencoe Falls. Queensland Parks and Wildlife Service, Government of Queensland. June 2012
The Kennedy Highway is a highway in northern Queensland, Australia. It runs as National Route 1 for 243 km from Smithfield, on the northern outskirts of Cairns, to the Gulf Developmental Road in the vicinity of Forty Mile Scrub and Undara Volcanic national parks. South of this junction, the road continues as the Kennedy Developmental Road to Boulia about 936 kilometres away, via Hughenden. West of the junction, National Route 1 continues as the Gulf Developmental Road to Normanton. From Smithfield, the highway climbs up into the Atherton Tableland before heading in a general south-westerly direction to the aforementioned junction; the highway is two-lanes. Major towns on, or just off, the Kennedy Highway include Smithfield, Mareeba, Atherton and Mount Garnet. Past Mount Garnet, the Kennedy Highway has several long sections of single lane bitumen; the section between The Lynd Roadhouse junction at Conjuboy and Hughenden is unsealed and is known as the Hann Highway. For a distance of more than 100 km, from the crossing on the Diamantina River to a point southwest of Middleton, the Kennedy Developmental Road passes across a circular zone measuring some 130 km across, identified by Geoscience Australia as a crustal anomaly.
Proof is lacking as to the cause, but it is believed that the anomaly was caused by an asteroid strike that happened about 300,000,000 years ago. Two northern councils have proposed development of the Hann Highway which would allow for the transport of products from Far North Queensland to markets in New South Wales and Victoria quicker than via existing coastal routes which have rougher terrain and are sometimes impassable due to floods. Highways in Australia List of highways in Queensland
Lake Eacham is a popular lake of volcanic origin on the Atherton Tableland of Queensland, within the World Heritage listed Wet Tropics of Queensland. Lake Eacham was formed over 9,130 years ago when molten magma from the Earth's mantle rose to the surface and heated the water table; the steam that resulted from the boiling water was trapped underground, until massive explosions signalled its release. Huge cracks appeared in the ground and the trees that once lathed the mountainside were levelled and burnt. After the eruptions, groundwater filled the crater and the trees grew back, creating the tranquil lake used today by families and tourists for recreation. There are no streams that flow into or out the lake, water is only lost through soakage and evaporation and only replenished through rainfall, the level can fluctuate up to 4 metres between wet and dry seasons; the nearby Lake Barrine formed in a similar way, over 17,300 years ago. The local Ngadjon -jii, name the lake Wiinggina and tell a parallel, matching story of the Lakes origins, as follows "Two young fellas were trying to spear that wallaby.
But they hit a flame tree. That’s a sacred tree; the young fellas not supposed to be out hunting. They weren’t initiated, their elders told them to stay put, not go out hunting. But they didn’t listen; when they pulled their spear out, part of a grub came out with the spear, a witchetty grub. They started cutting down that tree to get more grubs; when they cut down that tree, the ground began to shake. Those two fellas had made Yamini angry; the sky turned orange all these people back at the camp, the earth went from underneath them, sucked them in, they all got drowned. Where they were camped became Bana Wiingina." This story, in all its local versions, is part of an indigenous oral history and mythology believed to be an oral record recalling those volcanic events more than 10,000 years old. Back in 1886, Lake Eacham was included within original survey plans subdividing the whole of the Lake Eacham area into farming blocks. By 1888, the scenic value of the lake was recognised, both the lake plus a narrow band of'shoreline' rainforest were formally proclaimed "scenic reserve".
For 50 years the Lake was managed and enjoyed as a scenic reserve, with, at times and boating. In 1934, the Queensland Government declared the lake and immediate surrounds be protected and managed as Lake Eacham National Park. In 1988, UNESCO declared the Wet Tropics of Queensland a World Heritage site with 14 areas protected, two of which were 484 hectares at Lake Barrine and 505 hectares at Lake Eacham. In 1994, the Queensland Government merged Lake Barrine National Park and Lake Eacham National Park to form Crater Lakes National Park. Lake Eacham is isolated from any other watercourse. How any fish arrived there to begin with is a mystery, but somehow, the Lake Eacham rainbowfish found its way into the volcanic lake. For the small species, other larger fish were introduced into this closed system and these larger fish ate the Lake Eacham rainbowfish into extinction - at least as far as the lake was concerned. Aquarists had been collecting the fish from the Lake Eacham National Park and were successful at breeding them.
These private collections became the source stock to reintroduce the fish to the lake. However, the cause of the species' initial demise was still living in the lake and proceeded to deplete the entire population of reintroduced stock. Ichthyologists working in the rivers and streams of the Atherton Tableland have found the Lake Eacham rainbowfish in the Tully and Johnstone Rivers and Dirran Creek. In addition to the rainbowfish, Lake Eacham has two native fish species: The gudgeon Mogurnda adspersa and the hardyhead Craterocephalus stercusmuscarum. Other fish in the lake are non-native human introductions. Lake Eacham is the main feature of the 4.89 km² Crater Lakes National Park, with a dense rainforest and thousands of small animals. It is therefore a protected area under Queensland State legislation, and, as such, the natural and cultural resources most associated with the lake are protected and managed by the Queensland National Parks and Wildlife Service; the lake has an average depth of 38 metres with a maximum depth of 65.5 metres and is considered by locals as being ideal for swimming, canoeing and bird watching.
No motor boats are allowed on the lake. It features a pontoon great for diving into the deep water. A large grassy area is set aside for recreation. There is a circuit walk around the lake. There are a population of turtles that can be seen just to the left of the pontoon. Lake Euramoo List of lakes in Australia List of volcanoes in Australia Mount Hypipamee Crater Ngadjonji - Earthwatch web page. Accessed 5 November 2007 Wet Tropics Management Authority's Story of the Lake Eacham Rainbow Fish Accessed 11 November 2007 Recording of tourists swimming at Lake Eacham, hosted at'the freesound project'
The monsoon season is the time of year when most of a region's average annual rainfall occurs. The season lasts at least a month; the term "green season" is sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the subtropics. Under the Köppen climate classification, for tropical climates, a wet season month is defined as a month where average precipitation is 60 millimetres or more. In contrast to areas with savanna climates and monsoon regimes, Mediterranean climates have wet winters and dry summers. Dry and rainy months are characteristic of tropical seasonal forests: in contrast to tropical rainforests, which do not have dry or wet seasons, since their rainfall is distributed throughout the year; some areas with pronounced rainy seasons will see a break in rainfall mid-season, when the intertropical convergence zone or monsoon trough moves to higher latitudes in the middle of the warm season. When the wet season occurs during a warm season, or summer, precipitation falls during the late afternoon and early evening.
In the wet season, air quality improves, fresh water quality improves, vegetation grows leading to crop yields late in the season. Rivers overflow their banks, some animals retreat to higher ground. Soil nutrients erosion increases; the incidence of malaria increases in areas where the rainy season coincides with high temperatures in tropical areas. Some animals have survival strategies for the wet season; the previous dry season leads to food shortages in the wet season, as the crops have yet to mature. In areas where the heavy rainfall is associated with a wind shift, the wet season is known as the monsoon. Rainfall in the wet season is due to daytime heating which leads to diurnal thunderstorm activity within a pre-existing moist airmass, so the rain falls in late afternoon and early evening in savannah and monsoon regions. Further, much of the total rainfall each day occurs in the first minutes of the downpour, before the storms mature into their stratiform stage. Most places have only one wet season, but areas of the tropics can have two wet seasons, because the monsoon trough, or Intertropical Convergence Zone, can pass over locations in the tropics twice per year.
However, since rain forests have rainfall spread evenly through the year, they do not have a wet season. It is different for places with a Mediterranean climate. In the western United States, during the cold season from September–May, extratropical cyclones from the Pacific Ocean move inland into the region due to a southward migration of the jet stream during the cold season; this shift in the jet stream brings much of the annual precipitation to the region, sometimes brings heavy rain and strong low pressure systems. The peninsula of Italy has weather similar to the western United States in this regard. Areas with a savanna climate in Sub-Saharan Africa, such as Ghana, Burkina Faso, Eritrea and Botswana have a distinct rainy season. Within the savanna climate regime and South Texas have a rainy season. Monsoon regions include the Indian subcontinent, Southeast Asia, northern sections of Australia's North, Central America and southern Mexico, the Desert Southwest of the United States, southern Guyana, portions of northeast Brazil.
Northern Guyana has the other in early winter. In western Africa, there are two rainy seasons across southern sections, but only one across the north. Within the Mediterranean climate regime, the west coast of the United States and the Mediterranean coastline of Italy and Turkey experience a wet season in the winter months; the wet season in the Negev desert of Israel extends from October through May. At the boundary between the Mediterranean and monsoon climates lies the Sonoran desert, which receives the two rainy seasons associated with each climate regime; the wet season is known by many different local names throughout the world. For example, in Mexico it is known as "storm season". Different names are given to the various short "seasons" of the year by the Aboriginal tribes of Northern Australia: the wet season experienced there from December to March is called Gudjewg; the precise meaning of the word is disputed, although it is accepted to relate to the severe thunderstorms and abundant vegetation growth experienced at this time.
In tropical areas, when the monsoon arrives, high daytime high temperatures drop and overnight low temperatures increase, thus reducing diurnal temperature variation. During the wet season, a combination of heavy rainfall and, in some places such as Hong Kong, an onshore wind, improve air quality. In Brazil, the wet season is correlated with weaker trade winds off the ocean; the pH level of water becomes more balanced due to the charging of local aquifers during the wet season. Water softens, as the concentration of dissolved materials reduces during the rainy season. Erosion is increased during rainy periods. Arroyos that are dry at other times of the year fill with runoff, in some cases with water as deep as 10 feet. Leaching of soils during periods of heavy rainfall depletes nutrients; the higher runoff from land masses affects nearby ocean areas, which are more stratified, or less mixed, due to stronger surface currents forced by the heavy rainfall runoff. High rainfall can cause widespread flooding, which can lead to landslides and mudflows in mountainous areas.
Such floods cause rivers to submerge homes. The Ghaggar-Hakra River, which only flows during India's monsoon season, can flood and damage local
Windy Hill Wind Farm
Windy Hill Wind Farm is a wind power station near Ravenshoe on the Atherton Tablelands, Australia. Windy Hill has 20 wind turbines with a generating capacity of 12 MW of electricity, providing enough power for about 3,500 homes; the cost of the project was A$20 million. It was the first wind farm to be constructed in Queensland; the power station was commissioned in 2000 and was operated by the Stanwell Corporation. In December 2007 Windy Hill was sold to Transfield Services Infrastructure Fund as part of Queensland Government's ClimateSmart 2050 strategy. A new substation was built to allow the wind farm's power to connect to the existing 66 kV transmission line. RATCH-Australia Corporation bought TSIF in 2011; the construction contractor for the wind farm was Powercorp, based in Darwin. The wind turbines are located on private land; each tower is 44 metres high. The turbines used at the facility are Enercon E40, they can rotate at speeds between 14 rpm to 38 rpm. Power from the turbines is carried by underground cable to the electricity grid.
Wind power in Australia Official website