CIE IGCSE Geography The Shape of the River Recap 1. Label the letters A-F. 2. Label the drainage basin features shown on photos A-D. A C B D 3. Key Words a. What is an input? ……………………………………………………………………………………………………………………………………………. b. Give an example. ……………………………………………………………………………………………………………………………………………. c. What is a store? ……………………………………………………………………………………………………………………………………………… d. Give an example. ……………………………………………………………………………………………………………………………………………. Task Use the key words below to complete the table to work out what each definition means. Cross sectional area / Depth / Discharge / Velocity / Wetted perimeter / Width Key Term/Characteristic Definition River A River B The distance from bank to bank of the surface of the water of the river. Narrow / wide Narrow / wide How far down the water goes. This usually varies across a river, so an average is taken of several measurements. Shallow / deep Shallow / deep Slow / fast Slow / fast Low / high Low / high Small / large Small / large Low / high Low / high The speed at which the river is flowing. This varies with width. The length of the wet part of the channel cross-section containing flowing water. The area of flowing water when measured from bank to bank. The amount of water flowing in a channel. This is calculated by multiplying cross-sectional area by velocity. A Source B The Long and Cross Profile One of the most significant changes is to a river from source to mouth is its ……….……….………. ……….……….………. . The long profile shows the ……….……….………. of a river as it journeys from source to mouth. It is a way of displaying the channel slope (gradient) of a river along its entire length. Therefore, it shows how a river loses height with increasing distance towards the sea. The diagram below shows the cross profile of the River Tees and some of its features. High Fell, source of the River Tees Cauldron Snout High Force waterfall Barnard Castle River Tees close to Darlington Meanders south east of Darlington Stockton on Tees Tees Mouth As you can see the gradient of the river is very steep in its upper course. You will also notice several steep drops in the gradient at around 16 km from the source, then again at around 26 km. These are where waterfalls occur along the River Tees. You will also notice a flat section in the upper course indicating the location of Cow Green reservoir. Between 40 to 80km from the source the gradient contains to fall, though less rapidly. This is the middle course. From 80 km to the source (160 km) the gradient is very gentle in the lower course. The Cross Profile Not only does the long profile of the river change from source to mouth, so does the ……….……….………. ……….……….………. ……….……….………. . River valley cross profiles show you a cross-section, taken sideways, of a river valley at certain points in the river’s course. Each section of a river, the upper, middle and lower course, has their own valley cross-profile features. Valley Cross Profiles The upper course typically has V-shaped valleys. The river usually occupies most of the narrow valley floor. Vertical erosion creates Vshaped valleys as water flows around interlocking spurs (fingers of land that jut out into the river valley that streams and rivers are forced to flow around). In the upper course, the river erodes its bed by hydraulic action and abrasion (note from Miss Starling: we will cover this in the next few lessons!). As more tributaries join the river the volume of water increases, as does its erosive power. In the middle course the river valley becomes wider due to the increase in lateral (sideways) erosion. V-shaped valley with interlocking spurs in the upper course of a river In the lower course the river tends to be wider and deeper as the gradient becomes gentler leading to less vertical erosion. This part of the river can be tidal. Images and text source Task 1. Explain the difference between the long profile and the valley cross profile. Space has been provided to include a diagram to support your answer. ………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………………………………. 2. Complete the table below to describe the characteristics of the long profile and the valley cross profile for each stage of the River Tees. Long profile Upper Course Middle Course Lower Course Valley cross profile 3. Look at the photos below. Decide whether they show the upper or lower course of the river. Justify your decision (gives reasons for why you think this). Photo A: Upper / lower Photo B: Upper / lower I think this because I think this because ……………………………………………………………… ……………………………………………………………… …………………………………………………………….. …………………………………………………………….. ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… …………………………………………………………….. Photo B: Upper / lower …………………………………………………………….. Photo C: Upper / lower Photo D: Upper / lower I think this because I think this because ……………………………………………………………… ……………………………………………………………… …………………………………………………………….. …………………………………………………………….. ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… ……………………………………………………………… …………………………………………………………….. ……………………………………………………………..
