Search results
Results from the WOW.Com Content Network
This picture of the Nowitna River in Alaska shows two oxbow lakes – a short one at the bottom of the picture and a longer, more curved one at the middle-right. The picture also shows that a third oxbow lake is probably in the making: the isthmus or bank in the centre of the most prominent meander is very narrow – much narrower than the width of the river; eventually, the two sections of ...
A meander cutoff, also known as either a cutoff meander or abandoned meander, is a meander that has been abandoned by its stream after the formation of a neck cutoff. A lake that occupies a cutoff meander is known as an oxbow lake. Cutoff meanders that have cut downward into the underlying bedrock are known in general as incised cutoff meanders ...
When either of these meander cutoff processes takes place a bend of the river is left behind forming, in many instances, an oxbow lake. An oxbow lake forms after there has been deposition of sediment, by the new cutoff channel flowing adjacent to it, at the entrances of the abandoned bend; this seals the bend off from the rest of the river ...
Point bar at a river meander: the Cirque de la Madeleine in the Gorges de l'Ardèche, France. Any fluid, including water in a stream, can only flow around a bend in vortex flow. [1] In vortex flow the speed of the fluid is fastest where the radius of the flow is smallest, and slowest where the radius is greatest.
Most features of riverscapes include natural landforms (such as meanders and oxbow lakes) but they can also include artificial landforms (such as man-made levees and river groynes). Riverscapes can be divided into upper course riverscapes, middle course riverscapes, and lower course riverscapes.
When the original channel is cut off from the new channel by the deposition of sediments, oxbow lakes are formed. [3] Channel migration is important to sustaining diverse aquatic and riparian habitats [4] The migration causes sediments and woody debris to enter the river, and creates areas of new floodplain on the inside of the meander. [4]
Given enough time, the combination of erosion along cut banks and deposition along point bars can lead to the formation of an oxbow lake. Not only are cut banks steep and unstable, they are also the area of a stream where the water is flowing the fastest and often deeper. In geology, this is known as an area of "high-energy".
[3] [6] A terrace on the slip-off slope of a meander spur, known as slip-off slope terrace, can be formed by a brief halt during the irregular incision by an actively meandering river. [7] Aerial photograph of a meander on the Economy River, Nova Scotia. The gravel area on the inside of the meander near the centre-right of the image is a slip ...