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50-650: Laurelhurst Park is a city park in the neighborhood of Laurelhurst in Portland , Oregon . The 26.81-acre (10.85 ha) park was acquired in 1909 from the estate of former Portland mayor William S. Ladd . The City of Portland purchased the land in 1911, and the following year park superintendent Emanuel Mische designed the park in accordance with the Olmsted Plan . In 1919, the Pacific Coast Parks Association named Laurelhurst Park

100-402: A dragline . This technique is often used in excavation of bay mud . Most of these dredges are crane barges with spuds , steel piles that can be lowered and raised to position the dredge. A backhoe/dipper dredger has a backhoe like on some excavators . A crude but usable backhoe dredger can be made by mounting a land-type backhoe excavator on a pontoon . The six largest backhoe dredgers in

150-792: A water aeration and circulation system. In 1919, the Pacific Coast Parks Association named Laurelhurst Park the "most beautiful park" on the West Coast , and in February 2001 it was the first city park ever to be listed on the National Register of Historic Places . In February 2008 a woman's body was found partly submerged in the park's pond. In May 2009 a duck was killed after dozens of arrows were shot at waterfowl in Firwood Lake. In February 2010

200-613: A "High Class Residence Park," the Laurelhurst Company placed numerous restrictions on the neighborhood. Similar to the Ladd's Addition development, the sale of alcohol was prohibited. Additionally, there were to be no apartments, hotels, motels, flats, stables, or commercial buildings, and no homes were to be sold to Chinese, Japanese, or African Americans. The Laurelhurst Neighborhood Association (LNA) met as massive changes to Portland's transportation options were discussed in

250-490: A capacity of 6,000 cubic metres per hour (59,000 cu ft/ks). An even larger dredger, retired in 1980, was the U.S. Army Corps of Engineers Essayons , which was 525.17 feet (160.07 m) long. The Mallard II , a clamshell dredger that maintains levees in San Francisco Bay , has operated continuously since being built in 1936. Dredgers are often equipped with dredge monitoring software to help

300-439: A few different types of dredge hoses that differ in terms of working pressure, float-ability, armored or not etc. Suction hoses, discharge armored hoses and self-floating hoses are some of the popular types engineered for transporting and discharging dredge materials. Some even had the pipes or hoses customised to exact dredging needs etc. Other times, it is pumped into barges (also called scows ), which deposit it elsewhere while

350-567: A few situations the excavation is undertaken by a specialist floating plant , known as a dredger. Usually the main objectives of dredging is to recover material of value, or to create a greater depth of water. Dredging systems can either be shore-based, brought to a location based on barges , or built into purpose-built vessels. Dredging can have environmental impacts: it can disturb marine sediments , leading to both short- and long-term water pollution , damage or destroy seabed ecosystems , and can release legacy human-sourced toxins captured in

400-537: A larger parcel Ladd used to generate "one of the most prestigious stock farms in the West", later became too valuable for agricultural use. The City of Portland purchased the land in 1911 with the hope of establishing a park in accordance with the Olmsted Plan. Emanuel Mische, Portland's park superintendent from 1908 to 1914, designed the park in 1912 with experience he acquired as a longtime horticultural "expert" for

450-482: A long tube like some vacuum cleaners but on a larger scale. A plain suction dredger has no tool at the end of the suction pipe to disturb the material. A trailing suction hopper dredger (TSHD) trails its suction pipe when working. The pipe, which is fitted with a dredge drag head , loads the dredge spoil into one or more hoppers in the vessel. When the hoppers are full, the TSHD sails to a disposal area and either dumps

500-611: A man was reportedly held at gunpoint in northeast Portland, forced to drive to Laurelhurst Park, then beaten and sexually assaulted. Laurelhurst, Portland, Oregon In 1909, the Ladd Estate Company sold its 462-acre (1.87 km ) Hazelfern Farm to the Laurelhurst Company for approximately $ 2 million. The name Laurelhurst was borrowed from a residential development in Seattle that Laurelhurst Company general manager Paul Murphy had recently completed. The name combined

550-496: A process known as dewatering. Current dewatering techniques employ either centrifuges, geotube containers, large textile based filters or polymer flocculant /congealant based apparatus. In many projects, slurry dewatering is performed in large inland settling pits, although this is becoming less and less common as mechanical dewatering techniques continue to improve. Similarly, many groups (most notable in east Asia) are performing research towards utilizing dewatered sediments for

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600-541: A racial covenant governing development of Laurelhurst mandated "...nor shall the same or any part thereof be in any manner used or occupied by Chinese, Japanese or negroes, except that persons of said races may be employed as servants by residents." A 1934 redlining map of Portland assigned the areas within current Laurelhurst boundaries with a blue grade, or "Still Desirable." Regarding the B19 tract, mapmakers noted "homogenous surroundings, improvements, and population" as among

650-486: A reference to the laurel shrubbery near the Seattle development with the Old English hurst, denoting a wooded hill. The Laurelhurst Company platted a residential development of 144 acres (0.58 km ) with the help of co-investor and landscape architect John Charles Olmsted . As the first houses were being built, the city purchased 31 acres (130,000 m ) for $ 92,000 to construct Laurelhurst Park . Advertised as

700-411: A shipping channel through coral reefs . A bucket dredger is equipped with a bucket dredge, which is a device that picks up sediment by mechanical means, often with many circulating buckets attached to a wheel or chain . A grab dredger picks up seabed material with a clam shell bucket , which hangs from an onboard crane or a crane barge , or is carried by a hydraulic arm, or is mounted like on

750-544: Is 10 male/female pairs. In 1987, the normal duck population was 120, at times reaching more than 200, including migratory visitors. Murky water problems prompted Portland Parks & Recreation to attempt reducing the duck population, though an "adopt-a-duck" program was unsuccessful as the birds proved to be too difficult to catch. In 1990, lake sediment was being stirred up by nearly 20,000 catfish , carp , and black crappie fish. This overcrowding also led to odor problems. The Oregon Bass and Panfish Club attempted to reduce

800-526: Is a bar or blade which is pulled over the seabed behind any suitable ship or boat. It has an effect similar to that of a bulldozer on land. The chain-operated steam dredger Bertha , built in 1844 to a design by Brunel and as of 2009 was the oldest operational steam vessel in Britain, was of this type. This is an early type of dredger which was formerly used in shallow water in the Netherlands. It

850-424: Is mainly used in harbours and other shallow water. Excavator dredge attachments The excavator dredge attachment uses the characteristics of cutter-suction dredgers, consisting of cutter heads and a suction pump for transferring material. These hydraulic attachments mount onto the boom arm of an excavator allowing an operator to maneuver the attachment along the shoreline and in shallow water for dredging. This

900-410: Is usually sucked up by a wear-resistant centrifugal pump and discharged either through a pipe line or to a barge. Cutter-suction dredgers are most often used in geological areas consisting of hard surface materials (for example gravel deposits or surface bedrock) where a standard suction dredger would be ineffective. They can, if sufficiently powerful, be used instead of underwater blasting. As of 2024,

950-486: The Leiv Eriksson are: 46,000 cubic metre hopper and a design dredging depth of 155 m. Next largest is HAM 318 ( Van Oord ) with its 37,293 cubic metre hopper and a maximum dredging depth of 101 m. A cutter-suction dredger's (CSD) suction tube has a cutting mechanism at the suction inlet. The cutting mechanism loosens the bed material and transports it to the suction mouth. The dredged material

1000-481: The Nile were channelled and wharfs built at the time of the pyramids (4000 BC), there was extensive harbour building in the eastern Mediterranean from 1000 BC and the disturbed sediment layers gives evidence of dredging. At Marseille , dredging phases are recorded from the third century BC onwards, the most extensive during the first century AD. The remains of three dredging boats have been unearthed; they were abandoned at

1050-515: The Olmsted Brothers landscape design firm. Mische was guided by the firm's natural approach to landscaping and created seven distinct areas: the concert grove, Firwood Lake, children's lawn, plateau and broad meadows, picnic grove, and Rhododendron Hill. A spring-fed pond once used as a watering hole for cattle was deepened into a 3-acre (1.2 ha) lake. A "play park" was established between Oak and Stark Streets; here boys could play on

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1100-431: The "most beautiful park" on the West Coast , and in February 2001 it was the first city park ever to be listed on the National Register of Historic Places . The park costs the city approximately $ 274,000 per year to maintain. In 1909, the land that would later become Laurelhurst Park was purchased from the estate of William S. Ladd , the former Portland mayor who developed Ladd's Addition . The tract of land, part of

1150-580: The 1970s, which led to the creation of Trimet MAX Light Rail in the 1980s. LNA and the community endorsed light rail being placed in the Banfield corridor, but was strongly opposed to alignment along the Burnside corridor, either a busway or light rail. A 1978 petition submitted by 34 neighbors objected "to any parking, widening, or lane changes on East Burnside Street in the Laurelhurst area now or in

1200-532: The beds of streams. During the renaissance Leonardo da Vinci drew a design for a drag dredger. Dredging machines have been used during the construction of the Suez Canal from the late 1800s to present day expansions and maintenance. The completion of the Panama Canal in 1914, the most expensive U.S. engineering project at the time, relied extensively on dredging. These operate by sucking through

1250-620: The bottom of the harbour during the first and second centuries AD. The Banu Musa brothers during the Muslim Golden Age in while working at the Bayt-Al-Hikmah (house of wisdom) in Baghdad, designed an original invention in their book named ‘ Book of Ingenious Devices ’, a grab machine that does not appear in any earlier Greek works. The grab they described was used to extract objects from underwater, and recover objects from

1300-605: The construction industry. Dredging is a four-part process: loosening the material, bringing the material to the surface (together extraction), transportation and disposal. The extract can be disposed of locally or transported by barge or in a liquid suspension in pipelines. Disposal can be to infill sites, or the material can be used constructively to replenish eroded sand that has been lost to coastal erosion , or constructively create sea-walls, building land or whole new landforms such as viable islands in coral atolls . Ancient authors refer to harbour dredging. The seven arms of

1350-495: The dredge continues its work. A number of vessels, notably in the UK and NW Europe de-water the hopper to dry the cargo to enable it to be discharged onto a quayside 'dry'. This is achieved principally using self discharge bucket wheel, drag scraper or excavator via conveyor systems. When contaminated (toxic) sediments are to be removed, or large volume inland disposal sites are unavailable, dredge slurries are reduced to dry solids via

1400-482: The dredge operator position the dredger and monitor the current dredge level. The monitoring software often uses Real Time Kinematic satellite navigation to accurately record where the machine has been operating and to what depth the machine has dredged to. In a "hopper dredger", the dredged materials end up in a large onboard hold called a "hopper." A suction hopper dredger is usually used for maintenance dredging. A hopper dredge usually has doors in its bottom to empty

1450-425: The dredged materials, but some dredges empty their hoppers by splitting the two-halves of their hulls on large hydraulic hinges. Either way, as the vessel dredges, excess water in the dredged materials is spilled off as the heavier solids settle to the bottom of the hopper. This excess water is returned to the sea to reduce weight and increase the amount of solid material (or slurry) that can be carried in one load. When

1500-557: The environment, including the following: The nature of dredging operations and possible environmental impacts requires that the activity often be closely regulated and requires comprehensive regional environmental impact assessments alongside continuous monitoring. For example, in the U.S., the Clean Water Act requires that any discharge of dredged or fill materials into "waters of the United States," including wetlands,

1550-416: The fish population without success. By 2008, the lake had become acutely eutrophic (lacking oxygen), and the sediment layer had reduced the lake depth from 13 to 15 feet (4.0 to 4.6 m) to only 18 inches (46 cm). Each year, large amounts of blue-green algae were produced as the sun quickly heated the shallow water. In response, Portland City Council allocated funds to dredge the lake and install

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1600-527: The form of a scoop made of chain mesh, and are towed by a fishing boat . Clam-specific dredges can utilize hydraulic injection to target deeper into the sand. Dredging can be destructive to the seabed and some scallop dredging has been replaced by collecting via scuba diving . As of June 2018, the largest dredger in Asia is MV  Tian Kun Hao , a 140-metre (460 ft) long dredger constructed in China, with

1650-439: The future", calling it "a serious threat" to the neighborhood, that would lower property values, and be "a definite threat to our daily living pattern and destroy our neighborhood." The Portland-wide study noted a requirement to minimize projects "specifically in the Laurelhurst area". KXL-FM reported proximity to Laurelhurst Park was a selling point for realtors in this neighborhood until the homeless camp situation. In 1913

1700-447: The hopper is filled with slurry , the dredger stops dredging and goes to a dump site and empties its hopper. Some hopper dredges are designed so they can also be emptied from above using pumps if dump sites are unavailable or if the dredge material is contaminated. Sometimes the slurry of dredgings and water is pumped straight into pipes which deposit it on nearby land. These pipes are also commonly known as dredge hoses , too. There are

1750-469: The material could well suit the building industry, or could be used for beach nourishment. Dredging can disturb aquatic ecosystems , often with adverse impacts. In addition, dredge spoils may contain toxic chemicals that may have an adverse effect on the disposal area; furthermore, the process of dredging often dislodges chemicals residing in benthic substrates and injects them into the water column . Dredging can have numerous significant impacts on

1800-467: The material through doors in the hull or pumps the material out of the hoppers. Some dredges also self-offload using drag buckets and conveyors. As of 2008 the largest trailing suction hopper dredgers in the world were Jan De Nul 's Cristobal Colon (launched 4 July 2008 ) and her sister ship Leiv Eriksson (launched 4 September 2009 ). Main design specifications for the Cristobal Colon and

1850-467: The most powerful cutter-suction dredger in the world is DEME 's Spartacus , which entered service in 2021. The auger dredge system functions like a cutter suction dredger, but the cutting tool is a rotating Archimedean screw set at right angles to the suction pipe. Mud Cat invented the auger dredge in the 1970s. These use the Venturi effect of a concentrated high-speed stream of water to pull

1900-426: The nearby water, together with bed material, into a pipe. An airlift is a type of small suction dredge. It is sometimes used like other dredges. At other times, an airlift is handheld underwater by a diver . It works by blowing air into the pipe, and that air, being lighter than water, rises inside the pipe, dragging water with it. Some bucket dredgers and grab dredgers are powerful enough to rip out coral to make

1950-718: The neighborhood to increase housing availability. The Laurelhurst School was opened in 1918 and was originally named Scott School, after the first editor of The Oregonian . It was renamed to Laurelhurst School in 1925 along with the construction of the building that sits there today. Dredging Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features ; reshaping land and water features to alter drainage , navigability , and commercial use; constructing dams , dikes , and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value. In all but

2000-556: The neighborhood's favorable influences and called the subdivision's origins "a well conceived promotion, honestly administered"; regarding inhabitants, no foreign-born or Black inhabitants were reported. The official neighborhood representative Laurelhurst Neighborhood Association sought to prevent homeless camps within 1,000 feet (300 m) of schools, parks and where children congregate and further proposing that those who camp in this area be fined up to $ 100 or sent to jail for up to 30 days. Its members also vocally opposed development in

2050-426: The park pond "on floating boats and decorated rafts", drawing thousands of visitors. Junction City residents often held their annual picnic at Laurelhurst during the 1930s; the park has hosted many other picnics and reunions over the years. Easter Sunrise Services were held at the park during the 1950s, also drawing thousands of people. According to Portland Parks & Recreation, the park's ideal duck population

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2100-667: The production of concretes and construction block, although the high organic content (in many cases) of this material is a hindrance toward such ends. The proper management of contaminated sediments is a modern-day issue of significant concern. Because of a variety of maintenance activities, thousands of tonnes of contaminated sediment are dredged worldwide from commercial ports and other aquatic areas at high level of industrialization. Dredged material can be reused after appropriate decontamination. A variety of processes has been proposed and tested at different scales of application ( technologies for environmental remediation ). Once decontaminated,

2150-479: The seabed to bring the sediment in suspension, which then becomes a turbidity current , which flows away down slope, is moved by a second burst of water from the WID or is carried away in natural currents. Water injection results in a lot of sediment in the water which makes measurement with most hydrographic equipment (for instance: singlebeam echosounders) difficult. These dredgers use a chamber with inlets, out of which

2200-469: The seabed with its hull out of the water. Some forms can go on land. Some of these are land-type backhoe excavators whose wheels are on long hinged legs so it can drive into shallow water and keep its cab out of water. Some of these may not have a floatable hull and, if so, cannot work in deep water. Oliver Evans (1755–1819) in 1804 invented the Oruktor Amphibolos, an amphibious dredger which

2250-628: The sediment. These environmental impacts can reduce marine wildlife populations in some cases, contaminate sources of drinking water and interrupt economic activities such as fishing. Dredging is excavation carried out underwater or partially underwater, in shallow waters or ocean waters . It keeps waterways and ports navigable, and assists coastal protection, land reclamation and coastal redevelopment, by gathering up bottom sediments and transporting it elsewhere. Dredging can be done to recover materials of commercial value; these may be high value minerals or sediments such as sand and gravel that are used by

2300-560: The south side while girls played on the north side, and general games could be held on the east side. A comfort station building was built in 1914, and the following year a series of paths and sidewalks were lit by electric lights . Laurelhurst Park includes a basketball court, soccer field, tennis court, volleyball court, playground, dog off-leash area, historical site, horseshoe pit , paved and unpaved paths, picnic site with tables, public art, stage, and restrooms. The Portland Rose Festival Queen's Coronation used to take place in

2350-427: The water is pumped with the inlets closed. It is usually suspended from a crane on land or from a small pontoon or barge. Its effectiveness depends on depth pressure. A snagboat is designed to remove big debris such as dead trees and parts of trees from North America waterways. Some of these are any of the above types of dredger, which can operate normally, or by extending legs, also known as spuds, so it stands on

2400-705: The world are currently the Vitruvius, the Mimar Sinan, Postnik Yakovlev (Jan De Nul), the Samson (DEME), the Simson and the Goliath (Van Oord). They featured barge -mounted excavators. Small backhoe dredgers can be track-mounted and work from the bank of ditches. A backhoe dredger is equipped with a half-open shell. The shell is filled moving towards the machine. Usually dredged material is loaded in barges. This machine

2450-446: Was America's first steam-powered road vehicle. These are usually used to recover useful materials from the seabed. Many of them travel on continuous track . A unique variant is intended to walk on legs on the seabed. Fishing dredges are used to collect various species of clams , scallops , oysters or mussels from the seabed. Some dredges are also designed to catch crabs, sea urchins, sea cucumbers, and conch. These dredges have

2500-468: Was a flat-bottomed boat with spikes sticking out of its bottom. As tide current pulled the boat, the spikes scraped seabed material loose, and the tide current washed the material away, hopefully to deeper water. Krabbelaar is the Dutch word for "scratcher". A water injection dredger uses a small jet to inject water under low pressure (to prevent the sediment from exploding into the surrounding waters) into

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