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Highest Navigable Water Level
The reference water levels are used on inland waterways to define a range of water levels allowing the full use of the waterway for navigation. Ship passage can be limited by the water levels that are too low, when the fairway might become too shallow for large ("target", "design") ships, or too high, when it might become impossible for the target ships to pass under the bridges. The goal of establishing the reference water levels is to balance the safety of navigation and economic value of the waterway (for example, increase of the low level shortens the navigation season but allows the use of larger ships). Reference levels are set up based on statistics obtained from the multi-decadal observations (typically 30 years). Free-flowing rivers Free-flowing rivers use the low navigable water level (also lowest navigable water level, LNWL) as a low reference water level. When the river is at or above LNWL, the ships of the target draft can use its fairway. LNWL is usually defined a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inland Waterway
A body of water, such as a river, canal or lake, is navigable if it is deep, wide and calm enough for a water vessel (e.g. boats) to pass safely. Such a navigable water is called a ''waterway'', and is preferably with few obstructions against direct traverse that needed avoiding, such as rocks, reefs or trees. Bridges built over waterways must have sufficient clearance. High flow speed may make a channel unnavigable due to risk of ship collisions. Waters may be unnavigable because of ice, particularly in winter or high-latitude regions. Navigability also depends on context: a small river may be navigable by smaller craft such as a motorboat or a kayak, but unnavigable by a larger freighter or cruise ship. Shallow rivers may be made navigable by the installation of locks that regulate flow and increase upstream water level, or by dredging that deepens parts of the stream bed. Inland water transport systems Inland Water Transport (IWT) Systems have been used for centurie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fairway (navigation)
Fairway is a part of a water body (bay, harbor, river) containing the navigable channel (also known as a ship channel), a route suitable for ships of the larger size (with draft closer to the draft limit). Fairway depth, width, and height The underwater cross-section of a ship in the channel is limited by the fairway depth and width (bridges may create restrictions for the height above the waterline). Fairway depth is a distance between the seabed/riverbed and the water surface. The fairway depth of a river varies with the season, so some standardized depth value is used, usually the one corresponding to the low navigable water level (LNWL) defined as the water level that the river stays above during almost the entire navigation season: statistically, the level shall stay below the LNWL for 20 ice-free days per year, corresponding to 5-6% of the ice-free period on European rivers. The fairway width is defined as a width of the cross-section of the river that corresponds to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation Season
In the water transport, the navigation season (or shipping season) is a period of the year during which a waterway is open for navigation. The opening and closing dates of the season are determined annually by the waterway administration to accommodate the weather, water flow and ice conditions as well as the transportation demands. The term is also frequently used to designate number of days per year with easy navigation. Terminology In a general sense, in different contexts the term has slightly different meanings, multiple expressions are used: * ''summer navigation season''; * ''winter navigation season'' with some waterways closed; * ''ice-free navigations season'' / ''independent navigation period'' when the ships can get through without the assistance from an icebreaker. A ''traditional'' navigation season naturally varies from оne year to another, a ''fixed'' navigation season alternative sets firm dates for opening and closing (that can be changed based on conditions, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Draft (hull)
The draft or draught of a ship's hull is the vertical distance between the waterline and the bottom of the hull ( keel). The draught of the vessel is the maximum depth of any part of the vessel, including appendages such as rudders, propellers and drop keels if deployed. Draft determines the minimum depth of water a ship or boat can safely navigate. The related term air draft is the maximum height of any part of the vessel above the water. The more heavily a vessel is loaded, the deeper it sinks into the water, and the greater its draft. After construction, the shipyard creates a table showing how much water the vessel displaces based on its draft and the density of the water (salt or fresh). The draft can also be used to determine the weight of cargo on board by calculating the total displacement of water, accounting for the content of the ship's bunkers, and using Archimedes' principle. The closely related term "trim" is defined as the difference between the forward and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhine
The Rhine ; french: Rhin ; nl, Rijn ; wa, Rén ; li, Rien; rm, label=Sursilvan, Rein, rm, label=Sutsilvan and Surmiran, Ragn, rm, label=Rumantsch Grischun, Vallader and Puter, Rain; it, Reno ; gsw, Rhi(n), including in Alsatian dialect, Alsatian and Low Alemannic German; ksh, label=Ripuarian language, Ripuarian and Low Franconian languages, Low Franconian, Rhing; la, Rhenus ; hu, Rajna . is one of the major List of rivers of Europe, European rivers. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein, Swiss-Austrian border, Swiss-Austrian, Swiss-German border, Swiss-German borders. After that the Rhine defines much of the Franco-German border, after which it flows in a mostly northerly direction through the German Rhineland. Finally in Germany the Rhine turns into a predominantly westerly direction and flows into the Netherlands where it eventually empties into the North Sea. It drains an area of 9,9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Danube
The Danube ( ; ) is a river that was once a long-standing frontier of the Roman Empire and today connects 10 European countries, running through their territories or being a border. Originating in Germany, the Danube flows southeast for , passing through or bordering Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova, and Ukraine before draining into the Black Sea. Its drainage basin extends into nine more countries. The largest cities on the river are Vienna, Budapest, Belgrade and Bratislava, all of which are the capitals of their respective countries; the Danube passes through four capital cities, more than any other river in the world. Five more capital cities lie in the Danube's basin: Bucharest, Sofia, Zagreb, Ljubljana and Sarajevo. The fourth-largest city in its basin is Munich, the capital of Bavaria, standing on the Isar River. The Danube is the second-longest river in Europe, after the Volga in Russia. It flows through much of C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Engineering
River engineering is a discipline of civil engineering which studies human intervention in the course, characteristics, or flow of a river with the intention of producing some defined benefit. People have intervened in the natural course and behaviour of rivers since before recorded history—to manage the water resources, to protect against flooding, or to make passage along or across rivers easier. Since the Yuan Dynasty and Ancient Roman times, rivers have been used as a source of hydropower. From the late 20th century, the practice of river engineering has responded to environmental concerns broader than immediate human benefit. Some river engineering projects have focused exclusively on the restoration or protection of natural characteristics and habitats. Hydromodification encompasses the systematic response to alterations to riverine and non-riverine water bodies such as coastal waters (estuaries and bays) and lakes. The U.S. Environmental Protection Agency (EPA) has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canal
Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow under atmospheric pressure, and can be thought of as artificial rivers. In most cases, a canal has a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as ''slack water levels'', often just called ''levels''. A canal can be called a ''navigation canal'' when it parallels a natural river and shares part of the latter's discharges and drainage basin, and leverages its resources by building dams and locks to increase and lengthen its stretches of slack water levels while staying in its valley. A canal can cut across a drainage divide atop a ridge, generally requiring an external water source above the highest elevation. The best-known example of such a canal is the Panama C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can be used for any given locale to find the predicted times and amplitude (or "tidal range"). The predictions are influenced by many factors including the alignment of the Sun and Moon, the phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see '' Timing''). They are however only predictions, the actual time and height of the tide is affected by wind and atmospheric pressure. Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal tide—one high and low tide each day. A "mixed tide"—two uneven magnitude tides a day—is a third regular category. Tides va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock (water Navigation)
A lock is a device used for raising and lowering boats, ships and other watercraft between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself (usually then called a caisson) that rises and falls. Locks are used to make a river more easily navigable, or to allow a canal to cross land that is not level. Later canals used more and larger locks to allow a more direct route to be taken. Pound lock A ''pound lock'' is most commonly used on canals and rivers today. A pound lock has a chamber with gates at both ends that control the level of water in the pound. In contrast, an earlier design with a single gate was known as a flash lock. Pound locks were first used in China during the Song Dynasty (960–1279 AD), having been pioneered by the Song politician and naval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weir
A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of lakes, ponds, and reservoirs. There are many weir designs, but commonly water flows freely over the top of the weir crest before cascading down to a lower level. Etymology There is no single definition as to what constitutes a weir and one English dictionary simply defines a weir as a small dam, likely originating from Middle English ''were'', Old English ''wer'', derivative of root of ''werian,'' meaning "to defend, dam". Function Commonly, weirs are used to prevent flooding, measure water discharge, and help render rivers more navigable by boat. In some locations, the terms dam and weir are synonymous, but normally there is a clear distinction made between the structures. Usually, a dam is designed specifically to impound water beh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream Gauge
A stream gauge, streamgage or stream gauging station is a location used by hydrologists or environmental scientists to monitor and test terrestrial bodies of water. Hydrometric measurements of water level surface elevation (" stage") and/or volumetric discharge (flow) are generally taken and observations of biota and water quality may also be made. The locations of gauging stations are often found on topographical maps. Some gauging stations are highly automated and may include telemetry capability transmitted to a central data logging facility. Measurement equipment Automated direct measurement of streamflow discharge is difficult at present. In place of the direct measurement of streamflow discharge, one or more surrogate measurements can be used to produce discharge values. In the majority of cases, a stage (the elevation of the water surface) measurement is used as the surrogate. Low gradient (or shallow-sloped) streams are highly influenced by variable downstream ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
