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55-622: The Gold Coast Broadwater , also known as Southport Broadwater , Gold Coast Harbour and The Broadwater , is a large shallow estuary of water located in the Gold Coast district of South East Queensland , Australia. The estuary reaches from the locality of Southport in the south, to the southern section of the UNESCO World Heritage Listed Moreton Bay in the north. Separated via the Seaway from

110-633: A bridge for light rail on its western side and a pedestrian bridge on its eastern side. Construction of the Gold Coast Seaway was undertaken between 1984 and 1986. Plans for a cruise ship terminal and resort on Wave Break Island were rejected by the Queensland Government in 2015. On the 2 January 2023 a mid-air collision occurred between two helicopters undertaking tourist trips over the Broadwater. The Broadwaterway

165-573: A harsh environment for organisms. Sediment often settles in intertidal mudflats which are extremely difficult to colonize. No points of attachment exist for algae , so vegetation based habitat is not established. Sediment can also clog feeding and respiratory structures of species, and special adaptations exist within mudflat species to cope with this problem. Lastly, dissolved oxygen variation can cause problems for life forms. Nutrient-rich sediment from human-made sources can promote primary production life cycles, perhaps leading to eventual decay removing

220-529: A number of coastal water bodies such as coastal lagoons and brackish seas. A more comprehensive definition of an estuary is "a semi-enclosed body of water connected to the sea as far as the tidal limit or the salt intrusion limit and receiving freshwater runoff; however the freshwater inflow may not be perennial, the connection to the sea may be closed for part of the year and tidal influence may be negligible". This broad definition also includes fjords , lagoons , river mouths , and tidal creeks . An estuary

275-594: A number of watercourses including the Logan / Albert , Coomera , Pimpama and Nerang Rivers. Creeks such as the Loders , Biggera and Behm and Wasp also flow into the estuary. The most common seagrass species in the body of water is Zostera muelleri which grows in the shallower parts. Halophila ovalis and Halophila spinulosa are also found in the deeper waters of the Broadwater. Captain Patrick Logan

330-691: A period of time, both were in place until the demolition of the earlier bridge commenced. The Jubilee Bridge was on an east-west alignment commencing at Queen Street, Southport before ending in the vicinity of the Southport Yacht Club at Main Beach on the southern bank of the Nerang River. The Gold Coast Bridge was on a north-south alignment following the path of the Gold Coast Highway. The Gold Coast Bridge has since been joined by

385-408: A type of ecosystem in some estuaries that have been negatively impacted by eutrophication. Cordgrass vegetation dominates the salt marsh landscape. Excess nutrients allow the plants to grow at greater rates in above ground biomass, however less energy is allocated to the roots since nutrients is abundant. This leads to a lower biomass in the vegetation below ground which destabilizes the banks of

440-563: A well-mixed water column and the disappearance of the vertical salinity gradient . The freshwater-seawater boundary is eliminated due to the intense turbulent mixing and eddy effects . The lower reaches of Delaware Bay and the Raritan River in New Jersey are examples of vertically homogeneous estuaries. Inverse estuaries occur in dry climates where evaporation greatly exceeds the inflow of freshwater. A salinity maximum zone

495-436: A wholly marine embayment to any of the other estuary types. The most important variable characteristics of estuary water are the concentration of dissolved oxygen, salinity and sediment load. There is extreme spatial variability in salinity, with a range of near-zero at the tidal limit of tributary rivers to 3.4% at the estuary mouth. At any one point, the salinity will vary considerably over time and seasons, making it

550-477: A wide effect on the surrounding water bodies.  In turn, this can decrease fishing industry sales in one area and across the country. Production in 2016 from recreational and commercial fishing contributes billions of dollars to the United States' gross domestic product (GDP). A decrease in production within this industry can affect any of the 1.7 million people the fishing industry employs yearly across

605-492: Is a 19-kilometre (12 mi) foreshoreway along the foreshores of the Gold Coast Broadwater. The Broadwaterway includes: Fisherman's Wharf was located on the site of the present-day Versace Hotel. A popular and regionally iconic hospitality and entertainment complex (known to locals as Fishos), Fisherman's Wharf opened in 1983 before closing in 1998. Estuary Most existing estuaries formed during

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660-455: Is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides . The effects of tides on estuaries can show nonlinear effects on the movement of water which can have important impacts on the ecosystem and waterflow. The seawater entering the estuary is diluted by the fresh water flowing from rivers and streams. The pattern of dilution varies between different estuaries and depends on

715-513: Is derived from the Latin word aestuarium meaning tidal inlet of the sea, which in itself is derived from the term aestus , meaning tide. There have been many definitions proposed to describe an estuary. The most widely accepted definition is: "a semi-enclosed coastal body of water, which has a free connection with the open sea, and within which seawater is measurably diluted with freshwater derived from land drainage". However, this definition excludes

770-411: Is formed, and both riverine and oceanic water flow close to the surface towards this zone. This water is pushed downward and spreads along the bottom in both the seaward and landward direction. Examples of an inverse estuary are Spencer Gulf , South Australia, Saloum River and Casamance River , Senegal. Estuary type varies dramatically depending on freshwater input, and is capable of changing from

825-670: Is home to the world's first permanent sand bypassing system, which currently delivers all sand that arrives at the Gold Coast Seaway across the entrance and into the Moreton Bay Marine Park . Up to 500 cubic metres of sand can be moved per hour. The Gold Coast Shoreline Management Plan is reviewing this practice and examining the concept of Island welding to determine if 85% of the sand (80,000 cubic metres per year) can be sustainably recycled to Surfers Paradise . The bypass system uses ten pumps located along

880-566: Is less restricted, and there is a slow but steady exchange of water between the estuary and the ocean. Fjord-type estuaries can be found along the coasts of Alaska , the Puget Sound region of western Washington state , British Columbia , eastern Canada, Greenland , Iceland , New Zealand, and Norway. These estuaries are formed by subsidence or land cut off from the ocean by land movement associated with faulting , volcanoes , and landslides . Inundation from eustatic sea-level rise during

935-668: Is the Colorado River Delta in Mexico, historically covered with marshlands and forests, but now essentially a salt flat. Gold Coast Seaway The Gold Coast Seaway or Southport Seaway is the main navigation entrance from the Pacific Ocean into the Gold Coast Broadwater and southern Moreton Bay and is one of Australia's most significant coastal engineering projects. It is located at

990-646: Is the whitefish species from the European Alps . Eutrophication reduced the oxygen levels in their habitats so greatly that whitefish eggs could not survive, causing local extinctions. However, some animals, such as carnivorous fish, tend to do well in nutrient-enriched environments and can benefit from eutrophication. This can be seen in populations of bass or pikes. Eutrophication can affect many marine habitats which can lead to economic consequences. The commercial fishing industry relies upon estuaries for approximately 68 percent of their catch by value because of

1045-473: The Bureau of Meteorology . Two rock walls to stabilise the position of the entrance were constructed. One million tonnes of imported rock was used. To reduce the entry of ocean swells the breakwater walls were aligned 15 degrees north of east and increasing the length of the southern wall. Models indicated that the western shores of the Broadwater would need further protection from waves. Wave Break Island

1100-517: The Coral Sea by a thin strip of land called Stradbroke Island , the original body of water was a lagoon created from water deposited from the Nerang River . Part of the Broadwater is contained within the Moreton Bay Marine Park . The entrance of the Nerang River was at Main Beach in the late 19th century but by the 1980s had moved about 6 kilometres (3.7 mi) northwards. The Seaway

1155-748: The Holocene Epoch has also contributed to the formation of these estuaries. There are only a small number of tectonically produced estuaries; one example is the San Francisco Bay , which was formed by the crustal movements of the San Andreas Fault system causing the inundation of the lower reaches of the Sacramento and San Joaquin rivers . In this type of estuary, river output greatly exceeds marine input and tidal effects have minor importance. Freshwater floats on top of

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1210-473: The Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bays , harbors , lagoons , inlets , or sounds , although some of these water bodies do not strictly meet

1265-610: The Mandovi estuary in Goa during the monsoon period. As tidal forcing increases, river output becomes less than the marine input. Here, current induced turbulence causes mixing of the whole water column such that salinity varies more longitudinally rather than vertically, leading to a moderately stratified condition. Examples include the Chesapeake Bay and Narragansett Bay . Tidal mixing forces exceed river output, resulting in

1320-640: The Mid-Atlantic coast, and Galveston Bay and Tampa Bay along the Gulf Coast . Bar-built estuaries are found in a place where the deposition of sediment has kept pace with rising sea levels so that the estuaries are shallow and separated from the sea by sand spits or barrier islands. They are relatively common in tropical and subtropical locations. These estuaries are semi-isolated from ocean waters by barrier beaches ( barrier islands and barrier spits ). Formation of barrier beaches partially encloses

1375-734: The Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border. The width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped (in cross-section) in the inner part and broadening and deepening seaward. Water depths rarely exceed 30 m (100 ft). Examples of this type of estuary in the U.S. are the Hudson River , Chesapeake Bay , and Delaware Bay along

1430-478: The black-tailed godwit , rely on estuaries. Two of the main challenges of estuarine life are the variability in salinity and sedimentation . Many species of fish and invertebrates have various methods to control or conform to the shifts in salt concentrations and are termed osmoconformers and osmoregulators . Many animals also burrow to avoid predation and to live in a more stable sedimental environment. However, large numbers of bacteria are found within

1485-400: The United States. Estuaries are incredibly dynamic systems, where temperature, salinity, turbidity, depth and flow all change daily in response to the tides. This dynamism makes estuaries highly productive habitats, but also make it difficult for many species to survive year-round. As a result, estuaries large and small experience strong seasonal variation in their fish communities. In winter,

1540-513: The above definition of an estuary and could be fully saline. Many estuaries suffer degeneration from a variety of factors including soil erosion , deforestation , overgrazing , overfishing and the filling of wetlands. Eutrophication may lead to excessive nutrients from sewage and animal wastes; pollutants including heavy metals , polychlorinated biphenyls , radionuclides and hydrocarbons from sewage inputs; and diking or damming for flood control or water diversion. The word "estuary"

1595-452: The bottom where they are harmless. Historically the oysters filtered the estuary's entire water volume of excess nutrients every three or four days. Today that process takes almost a year, and sediment, nutrients, and algae can cause problems in local waters. Some major rivers that run through deserts historically had vast, expansive estuaries that have been reduced to a fraction of their former size, because of dams and diversions. One example

1650-502: The coast. Before the bypass system was implemented the mouth of the Nerang River moved northwards at a rate of 60 metres per year. This northward drift was responsible for the unstable and shifting conditions of the bar, which made crossing it hazardous for small boats. The southern training wall of the Gold Coast Seaway is the northern end of the Gold Coast Oceanway . The seaway is issued regular weather forecasts by

1705-472: The developed world, urbanisation surrounding the Broadwater is expected to continue. The region has important biodiversity values that have led to areas of the Broadwater listed as an international Ramsar site and inclusion to international migratory bird arrangements. The Broadwater provides a vital function in the provision of feeding, spawning and nursery sites for recreationally and commercially important finfish species. The Broadwater catchment includes

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1760-409: The dissolved oxygen from the water; thus hypoxic or anoxic zones can develop. Nitrogen is often the lead cause of eutrophication in estuaries in temperate zones. During a eutrophication event, biogeochemical feedback decreases the amount of available silica . These feedbacks also increase the supply of nitrogen and phosphorus, creating conditions where harmful algal blooms can persist. Given

1815-401: The effects of modifying the estuarine circulation. Fjord -type estuaries are formed in deeply eroded valleys formed by glaciers . These U-shaped estuaries typically have steep sides, rock bottoms, and underwater sills contoured by glacial movement. The estuary is shallowest at its mouth, where terminal glacial moraines or rock bars form sills that restrict water flow. In the upper reaches of

1870-601: The estuary impacted by human activities, and over time may shift the basic composition of the ecosystem, and the reversible or irreversible changes in the abiotic and biotic parts of the systems from the bottom up. For example, Chinese and Russian industrial pollution, such as phenols and heavy metals, has devastated fish stocks in the Amur River and damaged its estuary soil. Estuaries tend to be naturally eutrophic because land runoff discharges nutrients into estuaries. With human activities, land run-off also now includes

1925-424: The estuary, the depth can exceed 300 m (1,000 ft). The width-to-depth ratio is generally small. In estuaries with very shallow sills, tidal oscillations only affect the water down to the depth of the sill, and the waters deeper than that may remain stagnant for a very long time, so there is only an occasional exchange of the deep water of the estuary with the ocean. If the sill depth is deep, water circulation

1980-776: The estuary, with only narrow inlets allowing contact with the ocean waters. Bar-built estuaries typically develop on gently sloping plains located along tectonically stable edges of continents and marginal sea coasts. They are extensive along the Atlantic and Gulf coasts of the U.S. in areas with active coastal deposition of sediments and where tidal ranges are less than 4 m (13 ft). The barrier beaches that enclose bar-built estuaries have been developed in several ways: Fjords were formed where Pleistocene glaciers deepened and widened existing river valleys so that they become U-shaped in cross-sections. At their mouths there are typically rocks, bars or sills of glacial deposits , which have

2035-682: The ferry services which had transported passengers from the jetty, in the vicinity of later day Barney Street, across the water at the point where the Nerang River meets the Broadwater. In 1966-1967, the Jubilee Bridge was replaced by the Gold Coast Bridge, colloquially known as the Sundale Bridge due to its proximity to the Sundale Shopping Centre . The two bridges were on different alignments and, for

2090-609: The fish community is dominated by hardy marine residents, and in summer a variety of marine and anadromous fishes move into and out of estuaries, capitalizing on their high productivity. Estuaries provide a critical habitat to a variety of species that rely on estuaries for life-cycle completion. Pacific Herring ( Clupea pallasii ) are known to lay their eggs in estuaries and bays, surfperch give birth in estuaries, juvenile flatfish and rockfish migrate to estuaries to rear, and anadromous salmonids and lampreys use estuaries as migration corridors. Also, migratory bird populations, such as

2145-400: The great biodiversity of this ecosystem. During an algal bloom , fishermen have noticed a significant increase in the quantity of fish. A sudden increase in primary productivity causes spikes in fish populations which leads to more oxygen being utilized. It is the continued deoxygenation of the water that then causes a decline in fish populations. These effects can begin in estuaries and have

2200-420: The impacts do not end there. Plant death alters the entire food web structure which can result in the death of animals within the afflicted biome . Estuaries are hotspots for biodiversity , containing a majority of commercial fish catch, making the impacts of eutrophication that much greater within estuaries. Some specific estuarine animals feel the effects of eutrophication more strongly than others. One example

2255-536: The jetty. These are two metres beneath the sand. The pumps collect 500,000 cubic metres of sand over the course of a year. The sand, which is naturally moving northwards is pumped via a tunnel under the seaway to South Stradbroke Island, thereby making dredging unnecessary. It is managed by the Gold Coast Waterways Authority. Gold Coast Seaway is a popular diving and fishing location. Many surfers and body boarders regularly paddle across

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2310-525: The many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. Excess oxygen-depleting chemicals in the water can lead to hypoxia and the creation of dead zones . This can result in reductions in water quality, fish, and other animal populations. Overfishing also occurs. Chesapeake Bay once had a flourishing oyster population that has been almost wiped out by overfishing. Oysters filter these pollutants, and either eat them or shape them into small packets that are deposited on

2365-422: The marine environment, such as plastics , pesticides , furans , dioxins , phenols and heavy metals . Such toxins can accumulate in the tissues of many species of aquatic life in a process called bioaccumulation . They also accumulate in benthic environments, such as estuaries and bay muds : a geological record of human activities of the last century. The elemental composition of biofilm reflect areas of

2420-575: The marsh causing increased rates of erosion . A similar phenomenon occurs in mangrove swamps , which are another potential ecosystem in estuaries. An increase in nitrogen causes an increase in shoot growth and a decrease in root growth. Weaker root systems cause a mangrove tree to be less resilient in seasons of drought, which can lead to the death of the mangrove. This shift in above ground and below ground biomass caused by eutrophication could hindered plant success in these ecosystems. Across all biomes, eutrophication often results in plant death but

2475-670: The northern end of the Southport Spit where the Nerang River enters the Pacific Ocean. The channel was constructed between 1984 and 1986, primarily to facilitate the safe passage of sea-faring vessels. The passage was previously known as the Southport Bar. The mouth of the Nerang River was once located further south in Broadbeach . The main driving force for this movement is the northward drift of sand along

2530-440: The now off-balance nitrogen cycle , estuaries can be driven to phosphorus limitation instead of nitrogen limitation. Estuaries can be severely impacted by an unbalanced phosphorus cycle, as phosphorus interacts with nitrogen and silica availability. With an abundance of nutrients in the ecosystem, plants and algae overgrow and eventually decompose, which produce a significant amount of carbon dioxide. While releasing CO 2 into

2585-427: The seawater in a layer that gradually thins as it moves seaward. The denser seawater moves landward along the bottom of the estuary, forming a wedge-shaped layer that is thinner as it approaches land. As a velocity difference develops between the two layers, shear forces generate internal waves at the interface, mixing the seawater upward with the freshwater. An examples of a salt wedge estuary is Mississippi River and

2640-411: The sediment which has a very high oxygen demand. This reduces the levels of oxygen within the sediment often resulting in partially anoxic conditions, which can be further exacerbated by limited water flow. Phytoplankton are key primary producers in estuaries. They move with the water bodies and can be flushed in and out with the tides . Their productivity is largely dependent upon the turbidity of

2695-456: The volume of freshwater, the tidal range, and the extent of evaporation of the water in the estuary. Drowned river valleys are also known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley. This is the most common type of estuary in temperate climates. Well-studied estuaries include

2750-453: The water and atmosphere, these organisms are also intaking all or nearly all of the available oxygen creating a hypoxic environment and unbalanced oxygen cycle . The excess carbon in the form of CO 2 can lead to low pH levels and ocean acidification , which is more harmful for vulnerable coastal regions like estuaries. Eutrophication has been seen to negatively impact many plant communities in estuarine ecosystems . Salt marshes are

2805-835: The water. The main phytoplankton present are diatoms and dinoflagellates which are abundant in the sediment. A primary source of food for many organisms on estuaries, including bacteria , is detritus from the settlement of the sedimentation. Of the thirty-two largest cities in the world in the early 1990s, twenty-two were located on estuaries. As ecosystems, estuaries are under threat from human activities such as pollution and overfishing . They are also threatened by sewage, coastal settlement, land clearance and much more. Estuaries are affected by events far upstream, and concentrate materials such as pollutants and sediments. Land run-off and industrial, agricultural, and domestic waste enter rivers and are discharged into estuaries. Contaminants can be introduced which do not disintegrate rapidly in

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2860-473: The waterway. Curlew Island, a popular habitat for bird species including the Far Eastern curlew , emerged from the Broadwater over the last four decades. The Broadwater has undergone dramatic changes since the 1970s including the construction of an extensive number and network of artificial waterways that account for up to 90% of Australia's canal estates. Positioned in one of the fastest growing regions in

2915-550: Was completed in 1986 to stabilise the location of the Nerang River Entrance. Its construction has allowed greater tidal flows. This has created a larger tidal range within the Broadwater with lower low tides. Towards the northern end of the broadwater the Pimpama River enters. The broadwater is very large and contains lots of species of marine life. Gold Coast Ferries operates a number of services across

2970-433: Was constructed from dredged material to act as a barrier. The channel is 250 metres wide. The mean depth is 11 m and it has a maximum depth of 20 m. During outgoing tides, excess treated wastewater from four sewage treatment plants is released into the channel. Research conducted by the government indicated the quantity of sand movement necessitated a solution that operated perpetually. Gold Coast Seaway

3025-481: Was the first European to discover this southern entrance to Moreton Bay. In the early 1880s the first Southport Pier was opened to the public. On 26 November 1925, the Jubilee Bridge opened to pedestrian and vehicular traffic, becoming the first bridge to be erected in the Broadwater area. The bridge provided direct access between Southport and Main Beach and offered an alternative to, and eventually replaced,

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