Thursday, October 26, 2006

Higher Rivers Collaboration

This one's for Higher. Click on the picture above and you should then see a short video clip with a commentary from one of your peers. It's a good start, but is there anything else that could have been said about a) the river channel; b) the river valley; c) the processes at work in this stage of the river and d) the impact of the surrounding area on the hydrograph for this river-think maybe about different times of year? I will also set up another clip in class, which we can get some commentary on, and we'll do the same. Leave a comment by clicking below

16 comments:

13 said...

Potholes are also formed by the current aswell, as it creates a helicoidal flow, digging down on the river bed

Anonymous said...

The river itself is quite thin which is another feature of an upper course river. The river is also very straight and has no meanders which again is a feature of an upper course river. It is in a V shaped valley so there is steep sides, this means that rainwater,despite the vegetation,will flow into the river fairly quickly, creating an even faster discharge for the time of rainfall.
The large bedlam is due to the river not being able to move the large rocks and the water not being strong or plentiful enough to erode the rocks or even to cause attrition by banging them togeher.

26 said...

The river has no flood plain because it is in the higher course.

20 said...

the pot holes spinning goes in one direction, they are created by abrasion and mostly during floods.

28 said...

The woodland and vegetation would stop the water from running down the valley sides so quickly and also some water would be taken up (absorbed) by the roots.
The river's width is also relatively small, a common feature of an upper course river.
V-shaped valley suggests upper course and no flood plain.
(Most erosion occurs within the upper course of the river due to the large size of the river's bed load and the water flowing at a greater veolcity.)

2 said...

Hard to see whats going on, but the steep sides(V-shaped valley) tell us its in the upper course where the river wont be at its strongest. It wont be able to carry the large bedload, but traction might take place.

6 said...

drilling occurs where the pebbles rotate while lodged in the river bed, deppening the potholes. two or more potholes can join up to deepen the river bed relatively fast

22 said...

Downcutting might create a waterfall and then onto a Gorge.
Potholes are made by circular flow NOT a helicoidal flow.
Narrow width of river.

1 said...

As mentioned on the clip, the vegetation surroinding the river results in interception, therefore when a strom occurs, there will be a difference in time between the height of the storm and the maximum flow of the water, this is called lag time. The rising limb on the hydrograph would also have a more gentle gradient due to the vegetation.

maybe number 4? said...

the river is in its upper course meaning that it is at its most powerful and is able to carry the largest rocks. the river is small but it will be deepened and widened by abrasion and down cutting.

5 said...

As the river is in its upper course it will have alot of erosive power.This power is used to downcut the valley once this happens the sides of the valley are weathered to such and extent that they collapse creating a v -shaped valley

7 said...

2 said that this is the upper course, so the river won't be at it's strongest. In its upper course, the river is at its most erosoive, as it is when the water is fastest flowing, due to the steep gradient.

poo said...

As well as having a narrow channel, the river is also fairly straight because it has enough power (steep gradient) to erode straight through obstacles, only having to pick its way round interlocking spurs.
Apart from abrasion (corrasion) other processes at work in this river include hydraulic action, corrosion(solution) and attrition.
The surrounding area is an upland - so cold winter temperatures are likely. if the ground was frozen, this would lead to a shorter lag time.

14 said...

As 2 said,the only way the large bedload is going to be moved is by traction - which the river does have enough energy for, as there is a steep gradient. The river can also carry eroded material in suspension, or by saltation/ solution. The basin has steep sides, but the peak flow in the hydrograph is not as high as it might have been, obviously because of the vegetation but also because the area is not urbanised.

Anonymous said...

as we are told in the video, the vegetation that is nearby does cut down the discharge as it acts as an intercept and in turn lowers the curve in the hyrdrosphere graph

.29.

Anonymous said...

^^^^^^
above mistake, hydrograph, not hydrosphere graph :P