Misplaced Pages

#23976

22-508: The Jumpinpin channel , also known as The Pin , is a fast moving tidal deep water channel in Queensland , Australia. It was formed in 1898 and severed Stradbroke Island , originally one island, into North Stradbroke Island and South Stradbroke Island . Its name is derived from a Yugambeh word meaning Pandanus root. A channel in the general area of Jumpinpin may have formed and silted up several times over recent millennia. However,

44-487: A constant flux. Channel heads associated with hollows in steep terrain frequently migrate up and down hillslopes depending on sediment supply and precipitation. Natural channels are formed by fluvial process and are found across the Earth . These are mostly formed by flowing water from the hydrological cycle , though can also be formed by other fluids such as flowing lava can form lava channels . Channels also describe

66-420: Is a difference between low gradient streams (less than a couple of percent in gradient or slightly sloped) and high gradient streams (steeply sloped). A wide variety of stream channel types can be distinguished (e.g. braided rivers , wandering rivers, single-thread sinuous rivers etc.). During floods , water flow may exceed the capacity of the channel and flood waters will spill out of the channel and across

88-413: Is a stream of fluid lava contained within zones of static (i.e., solid and stationary) lava or lava levees. The initial channel may not contain levees per se, until the parental flow solidifies over what develops into the channel and creates natural levees. This initial levee allows for the building of a more complex levee and channel. As the lava flows through the channel, the elevation of the surface of

110-462: Is frequently called a canal , with the Panama Canal providing an example. The term not only includes the deep-dredged   ship-navigable parts of an estuary or river leading to port facilities, but also to lesser channels accessing boat port-facilities such as marinas . When dredged channels traverse bay mud or sandy bottoms, repeated dredging is often necessary because of

132-593: Is only by boat, however 4WD vehicles can access the southern tip of North Stradbroke Island, but the beach fishing is limited here. 27°43′59″S 153°26′31″E  /  27.733°S 153.442°E  / -27.733; 153.442 Channel (geography) Channels are important for the functionality of ports and other bodies of water used for navigability for shipping . Naturally, channels will change their depth and capacity due to erosion and deposition processes. Humans maintain navigable channels by dredging and other engineering processes. By extension,

154-661: Is the most upslope part of a channel network and is defined by flowing water between defined identifiable banks. A channel head forms as overland flow and/or subsurface flow accumulate to a point where shear stress can overcome erosion resistance of the ground surface. Channel heads are often associated with colluvium , hollows and landslides . Overland flow is a primary factor in channel initiation where saturation overland flow deepens to increase shear stress and begin channel incision. Overland flows converge in topographical depressions where channel initiation begins. Soil composition, vegetation, precipitation, and topography dictate

176-586: The valley bottom, floodplain or drainage area . Examples of rivers that are trapped in their channels: Grand Canyon and Black Canyon of the Gunnison . In a larger nautical context, as a geographical place name, the term channel is another word for strait , which is defined as a relatively narrow body of water that connects two larger bodies of water. In this nautical context, the terms strait , channel , sound , and passage are synonymous and usually interchangeable. For example, in an archipelago ,

198-545: The amount and rate of overland flow. The composition of a soil determines how quickly saturation occurs and cohesive strength retards the entrainment of material from overland flows. Vegetation slows infiltration rates during precipitation events and plant roots anchor soil on hillslopes. Subsurface flow destabilizes soil and resurfaces on hillslopes where channel heads are often formed. This often results in abrupt channel heads and landslides. Hollows form due to concentrated subsurface flows where concentrations of colluvium are in

220-672: The area was also affected by what was claimed to be changes in the water density interfering with the ability of the oysters to settle on the seafloor. The Jumpinpin Channel is renowned for fishing with huge catches of Bream , Flathead , Whiting , Luderick , Tailor and Trevally being made in season. Numerous Mulloway have been caught here. A few kilometres to the west of the bar an area known locally as Lew's Folly, produces large quantities of bream and flathead in season. Other areas known for their bream and flathead catches are Whalley's Gutter, Tiger Mullet Channel and Tree Gone Bay. Access

242-412: The beach. The ship broke up where she struck and most of the cargo was washed ashore and plundered by local residents. During the subsequent cleanup, explosives from the cargo were piled up and deliberately detonated on the beach, leaving large craters. The explosion is credited with severely damaging the beach and weakening the loosely vegetated sand dunes. Following gradual erosion of the seaward side of

SECTION 10

#1732776348024

264-463: The coast, coupled with the abnormally high tides, about Sunday and Monday, May 8 and 9, has effected a clean breach through the island, and there is now a deep channel about half a mile wide at Jumping Pin." Changes to tidal inundation in the area around the mouth of the Logan River were dramatic. Erosion occurred on farm land and some farmers resorted to building canals. The oyster industry in

286-567: The deeper course through a reef , sand bar , bay , or any shallow body of water. An example of a river running through a sand bar is the Columbia Bar —the mouth of the Columbia River . A stream channel is the physical confine of a stream ( river ) consisting of a bed and stream banks . Stream channels exist in a variety of geometries. Stream channel development is controlled by both water and sediment movement. There

308-478: The first official reporting being under date 13 May, coming from Mr Andrew Graham, Government official, Southport" TC Luita passed east of Brisbane 6–7 March 1898, producing gales and very high seas along the South Coast. Newspaper reports indicate that the passage was established in 1898. A sizeable breakthrough had taken place by that year. "News has now been received that the action of the recent gales on

330-631: The island over the next two years, the second event to ultimately generate the channel at Jumpinpin was the arrival of a cyclone in 1896. Thomas Welsby , writing in 1921, noted, "Within two years (1896) the southeast gales threw again their power and fury on the very spot whereat the Cambus Wallace had come to grief, drove the rollers and breakers against the sandy hillside until it conquered and made passage into Swan Bay." Welsby contradicts himself stating that "The break at Jumpinpin occurred in May, 1898,

352-446: The most recent formation of the channel is generally blamed on two events. The first of these was the wreck of the Cambus Wallace , a 75 m steel barque of 1534 tonnes built in 1894 at Port Glasgow . In the early morning of 3 September 1894, the Cambus Wallace ran aground in heavy seas near what was then a narrow stretch of Stradbroke Island called Tuleen. Most of the crew managed to swim to shore, but six men drowned and were buried on

374-400: The product of the sediment load and bed Bukhara size is proportional to the product of discharge and channel slope. A term " navigable channel " is used as a nautical term to mean a lane for ship travel, frequently marked (cf. Buoy ) and sometimes dredged . Thoresen distinguishes few categories of channels, from A (suitable for day and night navigation with guaranteed fairway depth ) all

396-430: The term also applies to fluids other than water, e.g., lava channels . The term is also traditionally used to describe the waterless surface features on Venus . Channel initiation refers to the site on a mountain slope where water begins to flow between identifiable banks. This site is referred to as the channel head and it marks an important boundary between hillslope processes and fluvial processes. The channel head

418-688: The unstable subsequent movement of benthic soils. Responsibility for monitoring navigability conditions of navigation channels to various port facilities varies, and the actual maintenance work is frequently performed by a third party. Storms, sea-states, flooding, and seasonal sedimentation adversely affect navigability . In the U.S., navigation channels are monitored and maintained by the United States Army Corps of Engineers (USACE), although dredging operations are often carried out by private contractors (under USACE supervision). USACE also monitors water quality and some remediation. This

440-512: The water between islands is typically called a channel or passage . The English Channel is the strait between England and France. The channel form is described in terms of geometry (plan, cross-sections, profile) enclosed by the materials of its bed and banks. This form is under influence of two major forces: water discharge and sediment supply. For erodible channels the mutual dependence of its parameters may be qualitatively described by Lane's Principle (also known as Lane's relationship ):

462-400: The way to D with no navigational aids and only estimated depths provided to the shipmaster . With regard to the dredging , channels can be unrestricted (wide enough to accommodate 10-15 widths of a largest ship used in this channel, semi-restricted with limited dredging in shallow waters, and fully restricted , where the entire channel is dredged. The latter, entirely human-made, channel

SECTION 20

#1732776348024

484-1320: Was first established under the Rivers and Harbors Act of 1899 and modified under acts of 1913, 1935, and 1938. For example, the USACE developed the Intracoastal Waterway , and has the Mississippi Valley Division responsible for the Mississippi River from the Gulf to Cairo, Illinois , the North Atlantic Division for New York Harbor and Port of Boston , and the South Pacific Division for Port of Los Angeles and Port of Long Beach . Waterways policing as well as some emergency spill response falls under United States Coast Guard jurisdiction, including inland channels serving ports like Saint Louis hundreds of miles from any coast. The various state or local governments maintain lesser channels, for example former Erie Canal . Lava channel A lava channel

#23976