62-575: Sir Richard Peninsula is a narrow peninsula consisting of sand which extends from Goolwa , South Australia to the Murray Mouth . It separates the Goolwa Channel, which is part of the estuary of the River Murray , from Encounter Bay . It is approximately 10 kilometres (6.2 mi) in length and ranges from 500 metres (1,600 ft)to 1 kilometre (0.62 mi) in width. The peninsula, together with
124-414: A breach may experience flooding similar to a natural event, while damage near a breach can be catastrophic, including carving out deep holes and channels in the nearby landscape. Under natural conditions, floodwaters return quickly to the river channel as water-levels drop. During a levee breach, water pours out into the floodplain and moves down-slope where it is blocked from return to the river. Flooding
186-400: A controlled inundation by the military or a measure to prevent inundation of a larger area surrounded by levees. Levees have also been built as field boundaries and as military defences . More on this type of levee can be found in the article on dry-stone walls . Levees can be permanent earthworks or emergency constructions (often of sandbags ) built hastily in a flood emergency. Some of
248-600: A distance of some 610 km (380 mi). The scope and scale of the Mississippi levees has often been compared to the Great Wall of China . The United States Army Corps of Engineers (USACE) recommends and supports cellular confinement technology (geocells) as a best management practice. Particular attention is given to the matter of surface erosion, overtopping prevention and protection of levee crest and downstream slope. Reinforcement with geocells provides tensile force to
310-422: A dyke may be a drainage ditch or a narrow artificial channel off a river or broad for access or mooring, some longer dykes being named, e.g., Candle Dyke. In parts of Britain , particularly Scotland and Northern England , a dyke may be a field wall, generally made with dry stone . The main purpose of artificial levees is to prevent flooding of the adjoining countryside and to slow natural course changes in
372-444: A high suspended sediment fraction and thus are intimately associated with meandering channels, which also are more likely to occur where a river carries large fractions of suspended sediment. For similar reasons, they are also common in tidal creeks, where tides bring in large amounts of coastal silts and muds. High spring tides will cause flooding, and result in the building up of levees. Both natural and man-made levees can fail in
434-428: A number of ways. Factors that cause levee failure include overtopping, erosion, structural failures, and levee saturation. The most frequent (and dangerous) is a levee breach . Here, a part of the levee actually breaks or is eroded away, leaving a large opening for water to flood land otherwise protected by the levee. A breach can be a sudden or gradual failure, caused either by surface erosion or by subsurface weakness in
496-549: A nursing facility in Goolwa. The spread of railways to inland Australia put an end to the river trade and Goolwa's significance as a port. With the decline of the river trade Goolwa became dependent on local farming and fishing, as well as becoming a popular destination for holidaymakers from Adelaide. In 1935 a permanent barrage (called the Goolwa Barrage ) was constructed between Hindmarsh Island and Sir Richard Peninsula on
558-754: A property-boundary marker or drainage channel. Where it carries a stream, it may be called a running dike as in Rippingale Running Dike , which leads water from the catchwater drain , Car Dyke, to the South Forty Foot Drain in Lincolnshire (TF1427). The Weir Dike is a soak dike in Bourne North Fen , near Twenty and alongside the River Glen , Lincolnshire . In the Norfolk and Suffolk Broads ,
620-519: A ridge and increasing the river channel's capacity. Alternatively, levees can be artificially constructed from fill , designed to regulate water levels. In some circumstances, artificial levees can be environmentally damaging . Ancient civilizations in the Indus Valley , ancient Egypt, Mesopotamia and China all built levees. Today, levees can be found around the world, and failures of levees due to erosion or other causes can be major disasters, such as
682-412: A shorter route to the ocean and begin building a new delta. Wave action and ocean currents redistribute some of the sediment to build beaches along the coast. When levees are constructed all the way to the ocean, sediments from flooding events are cut off, the river never migrates, and elevated river velocity delivers sediment to deep water where wave action and ocean currents cannot redistribute. Instead of
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#1732851095594744-421: A shorter time interval means higher river stage (height). As more levees are built upstream, the recurrence interval for high-water events in the river increases, often requiring increases in levee height. During natural flooding, water spilling over banks rises slowly. When a levee fails, a wall of water held back by the levee suddenly pours out over the landscape, much like a dam break. Impacted areas far from
806-447: A waterway to provide reliable shipping lanes for maritime commerce over time; they also confine the flow of the river, resulting in higher and faster water flow. Levees can be mainly found along the sea, where dunes are not strong enough, along rivers for protection against high floods, along lakes or along polders . Furthermore, levees have been built for the purpose of impoldering, or as a boundary for an inundation area. The latter can be
868-537: Is electrical resistivity tomography (ERT). This non-destructive geophysical method can detect in advance critical saturation areas in embankments. ERT can thus be used in monitoring of seepage phenomena in earth structures and act as an early warning system, e.g., in critical parts of levees or embankments. Large scale structures designed to modify natural processes inevitably have some drawbacks or negative impacts. Levees interrupt floodplain ecosystems that developed under conditions of seasonal flooding. In many cases,
930-594: Is 11,578. Every odd-numbered year, Goolwa hosts the South Australian Wooden Boat Festival (SAWBF). The town is a popular holiday destination and home to the PS Oscar W , a paddle steamer . Goolwa, along with the neighbouring towns of Middleton and Port Elliot and the city of Victor Harbor have in the 2000s enjoyed a nationally recognised " sea change " boom, with people moving there from more metropolitan areas for an improved lifestyle on
992-429: Is an elevated ridge , natural or artificial, alongside the banks of a river , often intended to protect against flooding of the area adjoining the river. It is usually earthen and often runs parallel to the course of a river in its floodplain or along low-lying coastlines. Naturally occuring levees form on river floodplains following flooding, where sediment and alluvium is deposited and settles, forming
1054-568: Is an historic river port on the Murray River near the Murray Mouth in South Australia . Goolwa is approximately 85 km (53 mi) south of Adelaide , and is joined by a bridge to Hindmarsh Island . The name "Goolwa" means "elbow" in the Ngarrindjeri language , and the area was known as "The Elbow" to the early settlers. Before 1837 the area was briefly considered for the site of
1116-546: Is below mean sea level. These typically man-made hydraulic structures are situated to protect against erosion. They are typically placed in alluvial rivers perpendicular, or at an angle, to the bank of the channel or the revetment , and are used widely along coastlines. There are two common types of spur dyke, permeable and impermeable, depending on the materials used to construct them. Natural levees commonly form around lowland rivers and creeks without human intervention. They are elongated ridges of mud and/or silt that form on
1178-420: Is important in order to design stable levee and floodwalls . There have been numerous studies to investigate the erodibility of soils. Briaud et al. (2008) used Erosion Function Apparatus (EFA) test to measure the erodibility of the soils and afterwards by using Chen 3D software, numerical simulations were performed on the levee to find out the velocity vectors in the overtopping water and the generated scour when
1240-451: Is permanently diverted through the gap. Sometimes levees are said to fail when water overtops the crest of the levee. This will cause flooding on the floodplains, but because it does not damage the levee, it has fewer consequences for future flooding. Among various failure mechanisms that cause levee breaches, soil erosion is found to be one of the most important factors. Predicting soil erosion and scour generation when overtopping happens
1302-573: Is prolonged over such areas, waiting for floodwater to slowly infiltrate and evaporate. Natural flooding adds a layer of sediment to the floodplain. The added weight of such layers over many centuries makes the crust sink deeper into the mantle , much like a floating block of wood is pushed deeper into the water if another board is added on top. The momentum of downward movement does not immediately stop when new sediment layers stop being added, resulting in subsidence (sinking of land surface). In coastal areas, this results in land dipping below sea level,
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#17328510955941364-505: Is some seasonal lag from oceanic influence, with average maxima ranging from 24.4 °C (75.9 °F) in February to 15.1 °C (59.2 °F) in July, and average minima fluctuating between 15.5 °C (59.9 °F) in February and 7.6 °C (45.7 °F) in July. Annual precipitation is moderately low, averaging 442.2 mm (17.41 in), between 144.3 precipitation days. Despite this,
1426-529: The Hindmarsh Island bridge , the construction of which had been a focus of national controversy during the 1990s . During 2008 and 2009 Goolwa suffered from one of the worst droughts in Australian history and the river which has sustained the town throughout its history was reduced to nothing much more than a channel and mudflats. The crisis prompted ongoing discussions with state and federal governments with
1488-512: The Nile Delta on the shores of the Mediterranean . The Mesopotamian civilizations and ancient China also built large levee systems. Because a levee is only as strong as its weakest point, the height and standards of construction have to be consistent along its length. Some authorities have argued that this requires a strong governing authority to guide the work and may have been a catalyst for
1550-632: The Younghusband Peninsula on the eastern side of the Murray Mouth, is the primary sand dune line defining this stretch of the Australian coastline. Sir Richard Peninsula was named after Richard Graves MacDonnell , the sixth governor of South Australia, and is located within the gazetted locality of Goolwa South . This South Australia geography article is a stub . You can help Misplaced Pages by expanding it . Goolwa, South Australia Goolwa , known as The Elbow to early settlers,
1612-627: The Coorong, Lower Lakes and Murray Mouth (CLLMM) Research Centre, run by the Goyder Institute for Water Research , opened, located between the Hindmarsh Island bridge and the barrage. The centre's focus is on studying and adapting to the effects of climate change in the region, by using both First Nations and scientific knowledge. Goolwa has a warm-summer mediterranean climate ( Köppen: Csb), with warm, dry summers and mild, wetter winters. There
1674-615: The Mississippi, stretching from Cape Girardeau , Missouri , to the Mississippi delta . They were begun by French settlers in Louisiana in the 18th century to protect the city of New Orleans . The first Louisiana levees were about 90 cm (3 ft) high and covered a distance of about 80 km (50 mi) along the riverside. The U.S. Army Corps of Engineers, in conjunction with the Mississippi River Commission, extended
1736-487: The aim of releasing more water from upstream to ensure the survival of the river. In 2009 a temporary levee (called the Clayton Regulator) was constructed between Clayton Bay and the north east side of Hindmarsh Island. The Regulator was put in place to protect the Goolwa Channel and its tributaries from the danger of acid sulfate soils . The low water level was exposing the river bed and scientific evidence warned of
1798-634: The catastrophic 2005 levee failures in Greater New Orleans that occurred as a result of Hurricane Katrina . Speakers of American English use the word levee , from the French word levée (from the feminine past participle of the French verb lever , 'to raise'). It originated in New Orleans a few years after the city's founding in 1718 and was later adopted by English speakers. The name derives from
1860-619: The city of Vancouver , British Columbia , there are levees (known locally as dikes, and also referred to as "the sea wall") to protect low-lying land in the Fraser River delta, particularly the city of Richmond on Lulu Island . There are also dikes to protect other locations which have flooded in the past, such as the Pitt Polder, land adjacent to the Pitt River , and other tributary rivers. Coastal flood prevention levees are also common along
1922-531: The coast. In March 2007, Goolwa was declared a Cittaslow by visiting Cittaslow representatives. Goolwa was the first non-European town to gain Cittaslow status. On 22 January 2010 the 4th stage of the Tour Down Under finished at Goolwa. As part of the event more than 8,000 cyclists, that participated in the preceding Mutual Community Challenge Tour , rode into Goolwa on the day. In early February 2024,
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1984-410: The colony's capital; a "special survey" was undertaken in 1839–40, with a sizeable township laid out at Currency Creek and land for a port with substantial warehousing on the river where Goolwa now stands. A wharf was constructed in 1852 and government buildings soon followed, including a post office in 1853. However, the treacherous waters of the Murray Mouth made it difficult for shipping and made
2046-573: The devastating impact of acidification of the Lower Lakes region. The Regulator immediately increased the water level between the Regulator and the Goolwa Barrage. In 2010 increased rainfall and water from upstream allowed the Regulator at Clayton Bay to be substantially removed. The rainfall has replenished much of the river and lower lakes. In late 2010 some gates on the Goolwa Barrage were opened for
2108-480: The development of systems of governance in early civilizations. However, others point to evidence of large-scale water-control earthen works such as canals and/or levees dating from before King Scorpion in Predynastic Egypt , during which governance was far less centralized. Another example of a historical levee that protected the growing city-state of Mēxihco-Tenōchtitlan and the neighboring city of Tlatelōlco,
2170-572: The earliest levees were constructed by the Indus Valley civilization (in Pakistan and North India from c. 2600 BCE ) on which the agrarian life of the Harappan peoples depended. Levees were also constructed over 3,000 years ago in ancient Egypt , where a system of levees was built along the left bank of the River Nile for more than 1,000 kilometers (600 miles), stretching from modern Aswan to
2232-479: The earth together. On the land side of high levees, a low terrace of earth known as a banquette is usually added as another anti-erosion measure. On the river side, erosion from strong waves or currents presents an even greater threat to the integrity of the levee. The effects of erosion are countered by planting suitable vegetation or installing stones, boulders, weighted matting, or concrete revetments . Separate ditches or drainage tiles are constructed to ensure that
2294-577: The first time in many years to allow fresh water to flow to the Murray Mouth. Continued rainfalls combined with flooding upstream in New South Wales and Victoria led to massive flows down the River Murray, and by January 2011 all the gates on the Goolwa Barrage were open. Goolwa is approximately 85 km (53 mi) south of Adelaide , and is the seat of the Alexandrina Council . It is in
2356-886: The foundation does not become waterlogged. Prominent levee systems have been built along the Mississippi River and Sacramento River in the United States , and the Po , Rhine , Meuse River , Rhône , Loire , Vistula , the delta formed by the Rhine, Maas/Meuse and Scheldt in the Netherlands and the Danube in Europe . During the Chinese Warring States period , the Dujiangyan irrigation system
2418-450: The impact is two-fold, as reduced recurrence of flooding also facilitates land-use change from forested floodplain to farms. In a natural watershed, floodwaters spread over a landscape and slowly return to the river. Downstream, the delivery of water from the area of flooding is spread out in time. If levees keep the floodwaters inside a narrow channel, the water is delivered downstream over a shorter time period. The same volume of water over
2480-456: The inland coastline behind the Wadden Sea , an area devastated by many historic floods. Thus the peoples and governments have erected increasingly large and complex flood protection levee systems to stop the sea even during storm floods. The biggest of these are the huge levees in the Netherlands , which have gone beyond just defending against floods, as they have aggressively taken back land that
2542-549: The laboratory tests, empirical correlations related to average overtopping discharge were derived to analyze the resistance of levee against erosion. These equations could only fit to the situation, similar to the experimental tests, while they can give a reasonable estimation if applied to other conditions. Osouli et al. (2014) and Karimpour et al. (2015) conducted lab scale physical modeling of levees to evaluate score characterization of different levees due to floodwall overtopping. Another approach applied to prevent levee failures
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2604-523: The levee system beginning in 1882 to cover the riverbanks from Cairo, Illinois to the mouth of the Mississippi delta in Louisiana. By the mid-1980s, they had reached their present extent and averaged 7.3 m (24 ft) in height; some Mississippi levees are as high as 15 m (50 ft). The Mississippi levees also include some of the longest continuous individual levees in the world. One such levee extends southwards from Pine Bluff , Arkansas , for
2666-420: The levee. A breach can leave a fan-shaped deposit of sediment radiating away from the breach, described as a crevasse splay . In natural levees, once a breach has occurred, the gap in the levee will remain until it is again filled in by levee building processes. This increases the chances of future breaches occurring in the same location. Breaches can be the location of meander cutoffs if the river flow direction
2728-468: The levees in the area, created for the purpose of farming the fertile tidal marshlands. These levees are referred to as dykes. They are constructed with hinged sluice gates that open on the falling tide to drain freshwater from the agricultural marshlands and close on the rising tide to prevent seawater from entering behind the dyke. These sluice gates are called " aboiteaux ". In the Lower Mainland around
2790-533: The main channel, this will make levee overtopping more likely again, and the levees can continue to build up. In some cases, this can result in the channel bed eventually rising above the surrounding floodplains, penned in only by the levees around it; an example is the Yellow River in China near the sea, where oceangoing ships appear to sail high above the plain on the elevated river. Levees are common in any river with
2852-445: The majority of The Lake being drained in the 17th century. Levees are usually built by piling earth on a cleared, level surface. Broad at the base, they taper to a level top, where temporary embankments or sandbags can be placed. Because flood discharge intensity increases in levees on both river banks , and because silt deposits raise the level of riverbeds , planning and auxiliary measures are vital. Sections are often set back from
2914-399: The ocean migrating inland, and salt-water intruding into freshwater aquifers. Where a large river spills out into the ocean, the velocity of the water suddenly slows and its ability to transport sand and silt decreases. Sediments begin to settle out, eventually forming a delta and extending to the coastline seaward. During subsequent flood events, water spilling out of the channel will find
2976-484: The overtopping water impinges the levee. By analyzing the results from EFA test, an erosion chart to categorize erodibility of the soils was developed. Hughes and Nadal in 2009 studied the effect of combination of wave overtopping and storm surge overflow on the erosion and scour generation in levees. The study included hydraulic parameters and flow characteristics such as flow thickness, wave intervals, surge level above levee crown in analyzing scour development. According to
3038-449: The rebellious Batavi pierced dikes to flood their land and to protect their retreat (70 CE ). The word dijk originally indicated both the trench and the bank . It closely parallels the English verb to dig . In Anglo-Saxon , the word dic already existed and was pronounced as dick in northern England and as ditch in the south. Similar to Dutch, the English origins of
3100-413: The river floodplains immediately adjacent to the cut banks. Like artificial levees, they act to reduce the likelihood of floodplain inundation. Deposition of levees is a natural consequence of the flooding of meandering rivers which carry high proportions of suspended sediment in the form of fine sands, silts, and muds. Because the carrying capacity of a river depends in part on its depth, the sediment in
3162-440: The river to form a wider channel, and flood valley basins are divided by multiple levees to prevent a single breach from flooding a large area. A levee made from stones laid in horizontal rows with a bed of thin turf between each of them is known as a spetchel . Artificial levees require substantial engineering. Their surface must be protected from erosion, so they are planted with vegetation such as Bermuda grass in order to bind
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#17328510955943224-617: The riverbed, even up to a point where the riverbed is higher than the adjacent ground surface behind the levees, are found for the Yellow River in China and the Mississippi in the United States. Levees are very common on the marshlands bordering the Bay of Fundy in New Brunswick and Nova Scotia , Canada . The Acadians who settled the area can be credited with the original construction of many of
3286-404: The soil to better resist instability. Artificial levees can lead to an elevation of the natural riverbed over time; whether this happens or not and how fast, depends on different factors, one of them being the amount and type of the bed load of a river. Alluvial rivers with intense accumulations of sediment tend to this behavior. Examples of rivers where artificial levees led to an elevation of
3348-415: The south eastern outskirts of Goolwa. The barrage separates the fresh water of the River Murray from the salt water coming up from the River Murray mouth. The barrage was constructed to prevent the salt water traversing further up the River Murray and polluting much needed fresh water. Goolwa had earlier been connected to Hindmarsh Island by a cable ferry; this was replaced in 2001 by the official opening of
3410-471: The state electoral district of Hammond and the federal Division of Mayo . At the 2011 census , the state suburb of Goolwa (excluding Goolwa Beach, Goolwa North and Goolwa South) had a population of 2,201. At June 2018, the estimated urban population for Goolwa together with nearby Victor Harbor was 26,532, having increased at an average annual rate of 1.07% year-on-year over the preceding five years. The portion of this combined urban area residing in Goolwa
3472-418: The town only has 46.3 clear days while having 181.5 cloudy days annually. Extreme temperatures have ranged from 43.0 °C (109.4 °F) on 14 January 1996 to 0.6 °C (33.1 °F) on 18 June 1998. Levee A levee ( / ˈ l ɛ v i / or / ˈ l ɛ v eɪ / ), dike ( American English ), dyke ( British English ; see spelling differences ), embankment , floodbank , or stop bank
3534-545: The town unsuitable as a major port. Goolwa nevertheless developed as Australia's first inland port (1853). Australia's first railway was opened in 1854 to connect Goolwa to Port Elliot . It was later extended to Victor Harbor , allowing goods to move from river boats to ships, so that neither had to negotiate the Murray Mouth. Goolwa was officially established in 1857. In 1919 the District Trained Nursing Society sent Clara Winifred Howie to establish
3596-488: The trait of the levee's ridges being raised higher than both the channel and the surrounding floodplains. The modern word dike or dyke most likely derives from the Dutch word dijk , with the construction of dikes well attested as early as the 11th century. The 126-kilometer-long (78 mi) Westfriese Omringdijk , completed by 1250, was formed by connecting existing older dikes. The Roman chronicler Tacitus mentions that
3658-494: The water which is over the flooded banks of the channel is no longer capable of keeping the same number of fine sediments in suspension as the main thalweg . The extra fine sediments thus settle out quickly on the parts of the floodplain nearest to the channel. Over a significant number of floods, this will eventually result in the building up of ridges in these positions and reducing the likelihood of further floods and episodes of levee building. If aggradation continues to occur in
3720-474: The word lie in digging a trench and forming the upcast soil into a bank alongside it. This practice has meant that the name may be given to either the excavation or to the bank. Thus Offa's Dyke is a combined structure and Car Dyke is a trench – though it once had raised banks as well. In the English Midlands and East Anglia , and in the United States, a dike is what a ditch is in the south of England,
3782-622: Was built by the Qin as a water conservation and flood control project. The system's infrastructure is located on the Min River , which is the longest tributary of the Yangtze River , in Sichuan , China . The Mississippi levee system represents one of the largest such systems found anywhere in the world. It comprises over 5,600 km (3,500 mi) of levees extending some 1,000 km (620 mi) along
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#17328510955943844-483: Was constructed during the early 1400s, under the supervision of the tlahtoani of the altepetl Texcoco, Nezahualcoyotl. Its function was to separate the brackish waters of Lake Texcoco (ideal for the agricultural technique Chināmitls ) from the fresh potable water supplied to the settlements. However, after the Europeans destroyed Tenochtitlan, the levee was also destroyed and flooding became a major problem, which resulted in
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