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34-748: Mangrove Creek Dam , a concrete faced rockfill embankment dam , is the primary reservoir for water supply to residents of the Central Coast in New South Wales , Australia . The dam, with a capacity of 190,000 megalitres (6,700 × 10 ^  cu ft) and fed by a catchment area of 101 square kilometres (39 sq mi), is operated by the Central Coast Water Corporation and supplies approximately 93 per cent of water to 300,000 residents in Central Coast Council . The dam

68-418: A dam and the filling of the reservoir behind it places a new weight on the floor and sides of a valley. The stress of the water increases linearly with its depth. Water also pushes against the upstream face of the dam, a nonrigid structure that under stress behaves semiplastically, and causes greater need for adjustment (flexibility) near the base of the dam than at shallower water levels. Thus the stress level of

102-422: A drain layer to collect seep water. A zoned-earth dam has distinct parts or zones of dissimilar material, typically a shell of locally plentiful material with a watertight clay core. Modern zoned-earth embankments employ filter and drain zones to collect and remove seep water and preserve the integrity of the downstream shell zone. An outdated method of zoned earth dam construction used a hydraulic fill to produce

136-736: A link was established between the Mangrove Creek Dam and Mardi Dam. This 21-kilometre (13 mi) Mardi-Mangrove Link is made up of two pipelines that enable water to be transferred from the Wyong River and Ourimbah Creek, via Mardi Dam to the large Mangrove Creek Dam for storage, instead of allowing it to flow to the ocean. It is expected that this link will help protect the Central Coast region against future extended periods of below-average rainfall. In 2022, After days of heavy rainfall Mangrove Creek Dam reached 100% capacity and began spilling over

170-564: A maximum water depth in the reservoir of 65 metres (213 ft). When at full supply, the reservoir has a surface level of approximately 7 square kilometres (2.7 sq mi), generated from the 101-square-kilometre (39 sq mi) catchment area and annual average rainfall of 960 millimetres (38 in). Sustained low water conditions, including a 15-year drought , took the level of water to 10.27% of total capacity during February 2007, following an earlier reading of 13.3% during January 2007. Local government officials immediately placed

204-458: A range of water restrictions on residents and businesses in order to conserve water and ensure ongoing supply to the region's residents and tourism industry. Piping of water from the Hunter River system augmented local water supply. In 2007, a water plan was established and detailed a program to expand supply and reduce demand to help secure the water supply until 2050. Between 2010 and 2012,

238-448: A rock-fill dam, rock-fill is blasted using explosives to break the rock. Additionally, the rock pieces may need to be crushed into smaller grades to get the right range of size for use in an embankment dam. Earth-fill dams, also called earthen dams, rolled-earth dams or earth dams, are constructed as a simple embankment of well-compacted earth. A homogeneous rolled-earth dam is entirely constructed of one type of material but may contain

272-404: A small sustained overtopping flow can remove thousands of tons of overburden soil from the mass of the dam within hours. The removal of this mass unbalances the forces that stabilize the dam against its reservoir as the mass of water still impounded behind the dam presses against the lightened mass of the embankment, made lighter by surface erosion. As the mass of the dam erodes, the force exerted by

306-686: A thick suspension of earth, rocks and water. Therefore, safety requirements for the spillway are high, and require it to be capable of containing a maximum flood stage. It is common for its specifications to be written such that it can contain at least a one-hundred-year flood. A number of embankment dam overtopping protection systems were developed in the early 21st century. These techniques include concrete overtopping protection systems, timber cribs , sheet-piles , riprap and gabions , Reinforced Earth , minimum energy loss weirs , embankment overflow stepped spillways , and precast concrete block protection systems. All dams are prone to seepage underneath

340-579: A watertight core. Rolled-earth dams may also employ a watertight facing or core in the manner of a rock-fill dam. The frozen-core dam is a temporary earth dam occasionally used in high latitudes by circulating a coolant through pipes inside the dam to maintain a watertight region of permafrost within it. Tarbela Dam is a large dam on the Indus River in Pakistan , about 50 km (31 mi) northwest of Islamabad . Its height of 485 ft (148 m) above

374-510: Is a concrete lined chute of approximately 240 metres (790 ft) with a width that tapers from 20 metres (66 ft) to 10 metres (33 ft), with the capacity to discharge a water flow of 570 cubic metres per second (20,000 cu ft/s) into the impounded Mangrove Creek. During 1989, the Boomerang Creek Tunnel was completed. This tunnel enabled water to be transferred from Mangrove Creek Dam to Wyong River , for extraction at

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408-490: The earth-filled dam (also called an earthen dam or terrain dam ) made of compacted earth, and the rock-filled dam . A cross-section of an embankment dam shows a shape like a bank, or hill. Most have a central section or core composed of an impermeable material to stop water from seeping through the dam. The core can be of clay, concrete, or asphalt concrete . This type of dam is a good choice for sites with wide valleys. They can be built on hard rock or softer soils. For

442-838: The 1970s. While all of the foregoing still exist, the modern day-tripper experience is usually by motor car as a result of the growth of car ownership. Also, airlines such as (formerly) Palmair promote day trips. In Germany in 2011, day trips were the predominant type of tourism. According to figures from the Hanover Chamber of Industry and Commerce, 2.84 billion day trippers spent an average of 28 euros in total (gross) that year, around 79.5 billion euros and 564 million Day business travelers €14.2 billion. Other surveys also assume an added value of between €20 and €30 per day tourist. The city of Berlin has, on average, calculated an added value of €32.50 per visitor in recent years with 132 million day visitors. The numbers are i. i.e. R. collected by

476-452: The U.S. Bureau of Reclamation Day-tripper A day trip is a visit to a tourist destination or visitor attraction from a person's home, hotel, or hostel in the morning, returning to the same lodging in the evening. The day trip is a form of recreational travel and leisure to a location that is close enough to make a round-trip within a day but does not require an overnight stay. The logistics and/or costs of spending nights on

510-577: The Wyong River Weir for storage in Mardi Dam. This water was then extracted downstream at Lower Wyong River Weir and pumped for storage in Mardi Dam. Mangrove Creek Dam was proposed as a large storage dam, not primarily a collection dam. Its catchment area was relatively small but the shape of the valley and its geology enabled the construction of a relatively high wall that would store 190,000 megalitres (6,700 × 10 ^  cu ft) of water, reaching

544-616: The asphalt make such dams especially suited to earthquake regions. For the Moglicë Hydro Power Plant in Albania the Norwegian power company Statkraft built an asphalt-core rock-fill dam. Upon completion in 2018 the 320 m long, 150 m high and 460 m wide dam is anticipated to be the world's highest of its kind. A concrete-face rock-fill dam (CFRD) is a rock-fill dam with concrete slabs on its upstream face. This design provides

578-428: The base to 300 millimetres (12 in) at the crest acts as a seal between the water and the dam embankment. Provision was made to increase the height of the dam wall by 25 metres (82 ft) to a total capacity of 420,000 megalitres (15,000 × 10 ^  cu ft) if the need arose in the future. The height of the dam wall is 80 metres (260 ft), with a length of 380 metres (1,250 ft). The dam spillway

612-536: The concrete slab as an impervious wall to prevent leakage and also a structure without concern for uplift pressure. In addition, the CFRD design is flexible for topography, faster to construct and less costly than earth-fill dams. The CFRD concept originated during the California Gold Rush in the 1860s when miners constructed rock-fill timber-face dams for sluice operations . The timber was later replaced by concrete as

646-406: The core is separated using a filter. Filters are specifically graded soil designed to prevent the migration of fine grain soil particles. When suitable building material is at hand, transport is minimized, leading to cost savings during construction. Rock-fill dams are resistant to damage from earthquakes . However, inadequate quality control during construction can lead to poor compaction and sand in

680-406: The dam must be calculated in advance of building to ensure that its break level threshold is not exceeded. Overtopping or overflow of an embankment dam beyond its spillway capacity will cause its eventual failure . The erosion of the dam's material by overtopping runoff will remove masses of material whose weight holds the dam in place and against the hydraulic forces acting to move the dam. Even

714-486: The dam, but embankment dams are prone to seepage through the dam as well; for example, the Usoi landslide dam leaks 35-80 cubic meters per second. Sufficiently fast seepage can dislodge a dam's component particles, which results in faster seepage, which turns into a runaway feedback loop that can destroy the dam in a piping-type failure. Seepage monitoring is therefore an essential safety consideration. gn and Construction in

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748-452: The design was applied to irrigation and power schemes. As CFRD designs grew in height during the 1960s, the fill was compacted and the slab's horizontal and vertical joints were replaced with improved vertical joints. In the last few decades, design has become popular. The tallest CFRD in the world is the 233 m-tall (764 ft) Shuibuya Dam in China , completed in 2008. The building of

782-566: The embankment which can lead to liquefaction of the rock-fill during an earthquake. Liquefaction potential can be reduced by keeping susceptible material from being saturated, and by providing adequate compaction during construction. An example of a rock-fill dam is New Melones Dam in California or the Fierza Dam in Albania . A core that is growing in popularity is asphalt concrete . The majority of such dams are built with rock and/or gravel as

816-465: The many piers around Victorian era seaside resorts . The General Slocum excursion was an example. Cycling became a very popular day-tripper activity, especially amongst urban and suburban workers, from the mid-1880s onwards. Coach and charabanc outings followed as the internal combustion engine became reliable enough to get the paying customers out and back again. Works outings and church or chapel excursions were extremely popular until

850-424: The primary fill. Almost 100 dams of this design have now been built worldwide since the first such dam was completed in 1962. All asphalt-concrete core dams built so far have an excellent performance record. The type of asphalt used is a viscoelastic - plastic material that can adjust to the movements and deformations imposed on the embankment as a whole, and to settlement of the foundation. The flexible properties of

884-501: The reservoir begins to move the entire structure. The embankment, having almost no elastic strength, would begin to break into separate pieces, allowing the impounded reservoir water to flow between them, eroding and removing even more material as it passes through. In the final stages of failure, the remaining pieces of the embankment would offer almost no resistance to the flow of the water and continue to fracture into smaller and smaller sections of earth or rock until they disintegrate into

918-399: The river bed and 95 sq mi (250 km ) reservoir make it the largest earth-filled dam in the world. The principal element of the project is an embankment 9,000 feet (2,700 m) long with a maximum height of 465 feet (142 m). The dam used approximately 200 million cubic yards (152.8 million cu. meters) of fill, which makes it one of the largest man-made structures in

952-570: The road are worth avoiding. Such travel of using one location as a homebase is popular with budget and active travelers to avoid finding new lodging at each destination. A caregiver may take a day trip from their home to return to their children or pets. In medieval times a destination for such a trip would be religious (to a nearby shrine ) or commercial (for example, to a seasonal fair ). Later, in England, visits to stately homes by those who regarded themselves middle class became frequent, and it

986-567: The spillway for the first time since construction of the dam was completed in 1982. The dam is a popular day trip destination for both locals and tourists for barbecues and picnics , taking about 45 minutes to reach by car from Gosford. Restrictions apply on accessing the dam and the catchment area in order to protect water quality, protect large areas of bush land and plant and animal habitats, protect threatened plants and animal species, and preserve evidence of Aboriginal occupation. Embankment dam Embankment dams come in two types:

1020-404: The upstream face and made of masonry , concrete , plastic membrane, steel sheet piles, timber or other material. The impervious zone may also be inside the embankment, in which case it is referred to as a "core". In the instances where clay is used as the impervious material, the dam is referred to as a "composite" dam. To prevent internal erosion of clay into the rock fill due to seepage forces,

1054-414: The world. Because earthen dams can be constructed from local materials, they can be cost-effective in regions where the cost of producing or bringing in concrete would be prohibitive. Rock -fill dams are embankments of compacted free-draining granular earth with an impervious zone. The earth used often contains a high percentage of large particles, hence the term "rock-fill". The impervious zone may be on

Mangrove Creek Dam - Misplaced Pages Continue

1088-534: Was constructed between 1978 and 1982, formed by impounding the headwaters of Mangrove Creek , a tributary of the Hawkesbury River . The concrete faced rockfill embankment dam was built due to a rising demand for water from the expanding population on the Central Coast. The dam was built to boost water supply storage and to help provide a more reliable water supply. Mangrove Creek Dam was built using rolled, soft rockfill of sandstones and siltstones. This material

1122-472: Was obtained from a quarry located within the storage area. These sandstones and siltstones were crushed and compacted to form the dam embankment. The embankment also contains approximately 100,000 cubic metres (3,500,000 cu ft) of processed basalt. This material was incorporated into various filters and drains within the embankment to cope with seepage within the embankment and foundations. The concrete face which tapers from 600 millimetres (24 in) at

1156-499: Was the tradition to reward the butler or housekeeper with a tip (gratuity) for providing access to their employer's home. As such homes were meant for show, it is unlikely that the owning family would object, provided they were not in residence at the time. The arrival of the railway excursion , often using Day Tripper tickets, in the mid 19th century saw the blossoming of a distinctive day-tripper industry. Trippers also travelled in their thousands by paddlesteamer or steamship to

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