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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 behind a wall, whilst a weir is designed ...
A weir may be used to trap marine fish in the intertidal zone as the tide recedes, fish such as salmon as they attempt to swim upstream to breed in a river, or eels as they migrate downstream. Alternatively, fish weirs can be used to channel fish to a particular location, such as to a fish ladder. Weirs were traditionally built from wood or stones.
In recent years the Salmon Conservancy has been installing fish ladders at weirs to allow salmon to travel up river. Today some weirs are often used recreationally by kayakers and canoeists for activities such as whitewater slalom and playboating. Specifically, Hambleden Weir and Boulter's Weir have EA sanctioned modifications made to them for ...
The weir itself is mostly submerged, now that a dam has raised water levels in the river. The weir, a collection of rocks arranged in a V shape, was used to trap fish. The two structures are the ...
These weirs were rebuilt seasonally at increasingly higher locations, as the ocean level continued to rise. Dendrochronological research documents that the wood species used for these weirs—sassafras, hickory, dogwood, beech, oak and alder—changed with the climate fluctuation. Analysis of tree rings and bark of recovered fishweir stakes ...
A weir was built on the Humber River (Ontario) to prevent a recurrence of a catastrophic flood. Flood management describes methods used to reduce or prevent the detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and runoff.
Weir on Lake Tecumseh, Virginia. A flow control structure is a device that alters the flow of water in a stream, drainage channel or pipe. As a group these are passive structures since they operate without intervention under different amounts of water flow and their impact changes based on the quantity of water available.
It has been used to fight blazes in the US since 1963, and is the main long-term fire retardant used by the California Department of Forestry and Fire Protection. It is also the most-used fire ...