Yazoo stream

Yazoo stream

AYazoo stream(also called aYazoo tributary) is ageologicandhydrologicterm for anytributarystream that runs parallel to, and within thefloodplainof a larger river for considerable distance, before eventually joining it. This is especially the characteristic when such a stream is forced to flow along the base of the main river'snatural levee.Where the two meet is known as a "belatedconfluence"or a" deferred junction ". The name is derived from an exterminated Native American tribe, theYazoo Indians.The Choctaw word is translated to "River of Death" because of the strong flows under its bank full stage.

Examples

Montana and Jordan Creeks

Yazoo River

Yazoo Riverruns parallel to theMississippi Riverfor 280 km (170 mi) before converging,being constrained from doing so upstream by the river's natural and man-madelevees.

Mossy Creek

Moesianstream/flow is a parallel derivative remnant ofpaleoriver.Many Yazoo streams are actually paleo-remnants of just one original river. The good examples of moesian flow areMossy Creek,MissouriandJezava,Morava.

Montana and Jordan creeks

Montana Creek, bankfull stage

Important salmonoid fish habitat and large spruce forests inhabit these streams which flow into theMendenhall Riverin Alaska.

Tributaries of the Wakarusa River

Yazoo streams here drain the back swamps of theWakarusa RiverValley.

Formation

Natural levees

Over time, the main river flows through the landscape, widening a valley and creating afloodplain.Sedimentaccumulates and creates a naturallevee.Tributariesthat want to enter the main channel are not allowed because of this levee. Instead, the water then enters the back swamps, or form a yazoo stream.Because yazoo streams are separated from the main river by natural levees, they flow and meander (streams and rivers rarely flow in straight lines) parallel to the main stream channel or river on thefloodplainfor a considerable distance. These series of smooth bends or curves flows with a slight gradient, and is normally blocked from entering by a natural leveealong the larger stream. A yazoo stream will join the major river where it will eventually break through the natural levees and flow into the larger waterway at its belated confluence.

Mendenhall Glacier

Yazoo stream formation can also be influenced by glacial processes. An example is the formation of the Montana Creek valley during the recentLittle Ice Age.TheMendenhall Glaciercarved out a widefloodplainthat is domed in the center. High valley walls due totectonic upliftandglacial outwash(the natural levee) create two yazoo streams that parallel the Mendenhall River.

Flooding and human influence

Floods are a major driving force for yazoo streams. In the Yazoo Basin,settlerswere faced with high waters for most of the year, making it hard for building homes and maintaining agriculture. A few man-madeleveeswere built to improve conditions. In 1927, large floods ravaged the area, allowingCongressto take action into building dams and more levees to reduce the risk of floods.

Human alteration withinwetlandsand streams have resulted in a decrease in ecological functions and associated benefits to society. Miles of streams are in poor condition with highnitrogenandphosphorusconcentrations. Yazoo streams have been altered through intense agricultural activities and flood control measures. Low water, excessive sedimentation, and the accumulation ofpesticidessuch asDDTare the consequences of human disturbances.