|Dendritic drainage pattern takes the form of "dendrites" and looks like the branching roots of a tree. Dendritic drainage forms where on flat surfaces of homogeneous subsurface material.|
|Example of trellis drainage pattern where juvenile streams (top to bottom) join secondary stream flowing from right to left. This is in the Babine Range. Trellis drainage is characteristic of areas with alternating parallel valleys and ridges. Streams occupy the valleys, flowing parallel to the ridges but occasionally cutting across the geological grain at water gaps.|
|The major landforms of Maui are featured in this photograph - the well-entrenched radial drainage pattern of Puukukui Volcano (1764 meters) at the west-northwest end of the island to Red Hill and Haleakala Crater (3055 meters) at the south end. Radial drainage patterns are typically found on the slopes of volcanoes, where streams flow downslope, parallel to the slope gradient.|
Notes on Carrying Processes:
River processes and landforms
|Mature rivers meander across wide river valleys and create large loop meanders that develop into oxbow lakes adjacent to the stream.|
It cuts and erodes into the outside of the curve and deposits sediment on the inside of the cure because the stream moves more rapidly on the outside of the curve and more slowly on the inside of the curve. (Think about the swing of a baseball bat - what part moves faster? The end of the bat is like the outside of the curve.) As the erosion and deposition continues, the curve becomes larger and more circular. Eventually, the river begins to cut the loop off by eroding the neck of the loop. The river breaks through at a cutoff and forms a new streambed. Sediment is then deposited on the loop side of the stream, cutting off the loop from the stream entirely and a crescent-shaped lake results. They are called oxbow lakes because they look like the bow part of the yoke used with teams of oxen.
|As glaciers melt, their runoff includes hundreds of tonnes of fine and coarse material. As the gradient of a river decreases, they begin to deposit gravelly debris. Crossing such flats, the river creates dozens of small, meandering channels. These become interwoven with each other into a braided channel. Since the amount of discharge varies almost hourly, the number of channels in a braided area will also vary.|
|Alluvial fans form where tributaries enter into broad valleys from the steep hillsides or mountain ranges. Coarser material is usually deposited at the top of the fan, and as a result, any stream flow quickly infiltrates and slows.|
|A waterfall is formed when hard rock is overlying softer rock
|Stream Piracy or stream capture is the natural diversion of the headwater of one stream into the channel of another stream having greater erosional activity. A decapitated stream or beheaded stream refers to the lower part of a stream whose headwaters have been captured by another stream. In some cases, decapitation may be accomplished by other geologic mechanisms, such as faulting.|
|Yazoo stream - tributary that follows parallel to the main channel until a breach in levee occurs |
Levees - sediment buildup near riverbank formed from deposition of coarse sediment during flooding
|A river rises in high ground ( its source ). It then flows down a slope ( its course ) until it reaches the sea ( its mouth ).|
The youthful stage :
Youthful rivers are usually small in size.
They usually flow quickly down steep slopes. Such fast flowing rivers generally erode the land over which they flow. Soft rock is usually more easily eroded than hard rock. Fast - flowing rivers usually erode more powerfully than slow flowing rivers.
The mature stage :
By the time the rivers has reached the mature stage the river will have received the waters of many tributaries.
So the river will have increased in size. As these larger rivers sweep quickly along they transport large loads of materials with them.
A rivers old age :
Old rivers meander slowly and aimlessly over almost flat plains as they near sea level. As they do so the rivers deposit much of the loads which they have carried in their mature stages.
Why old rivers deposit their loads : Rivers slow down when they enter almost-flat plains of old age. Slow moving rivers cannot carry large loads as fast flowing rivers can. So the old rivers deposit their loads. The loads of old rivers consist of light particles such as mud and grains of sand. This material is called alluvium. It is deposited along the river bed.
|Deltas are found at the mouth of large rivers - for example, the Mississippi. A delta is formed when the
river deposits its material faster than the sea can remove it. There are three main types of delta, named after the
shape they create: |
Arcuate - the land around the river mouth arches out into the sea, the river splits many times on the way to the sea, creating a fan effect.
Cuspate - the land around the mouth of the river juts out arrow-like into the sea.
Bird's foot - the river splits on the way to the sea, each part of the river juts out into the sea, rather like a bird's foot.
Download the assignment here: Wind Processes and Landforms!!
OPEN a separate Word Document. Here you will be placing images and text.
|Location||Why wind is effective|
Water action in the desert