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Stream Crossing
:''This article covers crossings over small streams, not those over large rivers.'' Stream crossings are the numerous instances where small perennial or intermittent streams are crossed by roads, pipelines, railways, or any other thing which might restrict the flow of the steam in ordinary or flood conditions. Crossings over any dry channel which might carry flood water is included. Any structure over or in a stream which results in limitations on the movement of fish or other ecological elements can be an issue. Types In addition to bridges and culverts streams may be crossed by fords, floodways, low-water crossings or even stepping stones. Conveyance capacity Often expressed in cubic feet per second (cfs), conveyance capacity is the amount of water a stream crossing structure will pass. The amount of water that can be predicted during flood conditions, such as a 100-year flood is one design consideration. Failure to convey If stream flow exceeds the capacity of the passage th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams are usually called rivers, while smaller, less voluminous and more intermittent river, intermittent streams are known as streamlets, brooks or creeks. The flow of a stream is controlled by three inputs – surface runoff (from precipitation or meltwater), daylighting (streams), daylighted subterranean river, subterranean water, and surfaced groundwater (Spring (hydrology), spring water). The surface and subterranean water are highly variable between periods of rainfall. Groundwater, on the other hand, has a relatively constant input and is controlled more by long-term patterns of precipitation. The stream encompasses surface, subsurface and groundwater fluxes th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stepping Stones
Stepping stones or stepstones are sets of stones arranged to form an improvised causeway that allows a pedestrian to cross a natural watercourse such as a river; or a water feature in a garden where water is allowed to flow between stone steps. Unlike bridges, stepstone crossings typically have no spans, although wood planks or stone slabs can be placed over between the stones (which serve as the piers) to improvise as low-water bridges. Although their historical origin is unknown, stepping stones, along with log bridges, are likely to have been one of the earliest forms of crossing inland bodies of water devised by humans. In traditional Japanese gardens, the term "''iso-watari''" refers to stepping stone pathways that lead across shallow parts of a pond, which work like a bridge-like slower crossing. Using ''iso-watari'' for crossing ponds, or shallow parts of streams, one can view the aquatic animals and plants around or in the pond, like carp, turtles, and waterfowls. Today, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Log Bridge
A log bridge is a timber bridge that uses logs that fall naturally or are intentionally felled or placed across streams. The first man-made bridges with significant span were probably intentionally felled trees. The use of emplaced logs is now sometimes used in temporary bridges used for logging roads, where a forest tract is to be harvested and the road then abandoned. Such log bridges have a severely limited lifetime due to soil contact and subsequent rot and wood-eating insect infestation. Longer lasting log bridges may be constructed by using treated logs and/or by providing well drained footings National Parks Conference 1915, p. 59. "If we can design the abutment so that no moisture can collect under the logs the life of the bridge is materially increased." of stone or concrete combined with regular maintenance to prevent soil infiltration. This care in construction can be seen in the French bridge illustrated below, which has well locked dry set stone abutments and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massachusetts Department Of Transportation
The Massachusetts Department of Transportation (MassDOT) oversees roads, public transit, aeronautics, and transportation licensing and registration in the US state of Massachusetts. It was created on November 1, 2009, by the 186th Session of the Massachusetts General Court upon enactment of the ''2009 Transportation Reform Act.'' History In 2009, Governor Deval Patrick proposed merging all Massachusetts transportation agencies into a single Department of Transportation. Legislation consolidating all of Massachusetts' transportation agencies into one organization was signed into law on June 26, 2009. The newly established Massachusetts Department of Transportation (MASSDOT) assumed operations from the existing conglomeration of state transportation agencies on November 1, 2009. This change included: * Creating the Highway Division from the former Massachusetts Turnpike Authority and Massachusetts Highway Department, MassHighways. * Assuming responsibility for the planning and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Continuity
A wildlife corridor, habitat corridor, or green corridor is an area of habitat connecting wildlife populations separated by human activities or structures (such as roads, development, or logging). This allows an exchange of individuals between populations, which may help prevent the negative effects of inbreeding and reduced genetic diversity (via genetic drift) that often occur within isolated populations. Corridors may also help facilitate the re-establishment of populations that have been reduced or eliminated due to random events (such as fires or disease). This may potentially moderate some of the worst effects of habitat fragmentation, wherein urbanization can split up habitat areas, causing animals to lose both their natural habitat and the ability to move between regions to use all of the resources they need to survive. Habitat fragmentation due to human development is an ever-increasing threat to biodiversity, and habitat corridors are a possible mitigation. Purpose T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmon
Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the North Atlantic (genus ''Salmo'') and North Pacific (genus ''Oncorhynchus'') basin. Other closely related fish in the same family include trout, Salvelinus, char, Thymallus, grayling, Freshwater whitefish, whitefish, lenok and Hucho, taimen. Salmon are typically fish migration, anadromous: they hatch in the gravel stream bed, beds of shallow fresh water streams, migrate to the ocean as adults and live like sea fish, then return to fresh water to reproduce. However, populations of several species are restricted to fresh water throughout their lives. Folklore has it that the fish return to the exact spot where they hatched to spawn (biology), spawn, and tracking studies have shown this to be mostly true. A portion of a returning salmon run ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
100-year Flood
A 100-year flood is a flood event that has a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The 100-year flood is also referred to as the 1% flood, since its annual exceedance probability is 1%.Holmes, R.R., Jr., and Dinicola, K. (2010) ''100-Year flood–it's all about chance 'U.S. Geological Survey General Information Product 106/ref> For coastal or lake flooding, the 100-year flood is generally expressed as a flood elevation or depth, and may include wave effects. For river systems, the 100-year flood is generally expressed as a flowrate. Based on the expected 100-year flood flow rate, the flood water level can be mapped as an area of inundation. The resulting floodplain map is referred to as the 100-year floodplain. Estimates of the 100-year flood flowrate and other streamflow statistics for any stream in the United States are available.Ries, K.G., and others (2008) ''StreamStats: A water resources web application 'U.S. Geological Survey, Fac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cubic Feet Per Second
Cubic may refer to: Science and mathematics * Cube (algebra), "cubic" measurement * Cube, a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex ** Cubic crystal system, a crystal system where the unit cell is in the shape of a cube * Cubic function, a polynomial function of degree three * Cubic equation, a polynomial equation (reducible to ''ax''3 + ''bx''2 + ''cx'' + ''d'' = 0) * Cubic form, a homogeneous polynomial of degree 3 * Cubic graph (mathematics - graph theory), a graph where all vertices have degree 3 * Cubic plane curve (mathematics), a plane algebraic curve ''C'' defined by a cubic equation * Cubic reciprocity (mathematics - number theory), a theorem analogous to quadratic reciprocity * Cubic surface, an algebraic surface in three-dimensional space * Cubic zirconia, in geology, a mineral that is widely synthesized for use as a diamond simulacra * CUBIC, a histology method Computing * Cubic IDE, a modular dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-water Crossing
A low-water crossing (also known as an Irish bridge or Irish Crossing, causeway in Australia, low-level crossing or low-water bridge) provides a bridge when water flow is low. Under high-flow conditions, water runs over the roadway and precludes vehicular traffic. This approach is cheaper than building a bridge to raise the level of the road above the highest flood stage of a river, particularly in developing countries or in semi-arid areas with rare high-volume rain. Low-water crossings can be dangerous when flooded. Construction The low-water crossing was developed from the traditional ford. A ford permits vehicular traffic to cross a waterway with wet wheels. In some countries the term “low-water crossing” implies that the crossing is usually dry, while “ford” implies that the crossing is usually wet. The simplest type of low water crossing is called an ''unvented ford'' or ''drift''. This type of low water crossing is used mainly for shallow waterways or dry stream ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of roads, including parkways, avenues, controlled-access highways (freeways, motorways, and expressways), tollways, interstates, highways, thoroughfares, and local roads. The primary features of roads include lanes, sidewalks (pavement), roadways (carriageways), medians, shoulders, verges, bike paths (cycle paths), and shared-use paths. Definitions Historically many roads were simply recognizable routes without any formal construction or some maintenance. The Organization for Economic Co-operation and Development (OECD) defines a road as "a line of communication (travelled way) using a stabilized base other than rails or air strips open to public traffic, primarily for the use of road motor vehicles running on their own wheels", whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floodway (road)
A floodway is a flood plain crossing for a road, built at or close to the natural ground level. It is similar to a causeway, but crosses a shallow depression that is subject to flooding, rather than a waterway or tidal water. They are designed to be submerged under water, but withstand such conditions. Typically floodways are used when the flood frequency or time span is minimal, traffic volumes are low, and the cost of a bridge is uneconomic – in most cases, in rural areas. See also *Flood control channel * Glossary of road transport terms *Low water crossing A low-water crossing (also known as an Irish bridge or Irish Crossing, causeway in Australia, low-level crossing or low-water bridge) provides a bridge when water flow is low. Under high-flow conditions, water runs over the roadway and precl ... Notes * * * External links Flood control Transportation engineering Rivers Hydraulic engineering {{road-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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