Rivers past exam questions quiz

1. Rivers past exam questions quiz For each question (1-33), choose the most appropriate or the best answer from either a, b or c.

2. 1/ 1999 P3H Explain the differences in the size and shape of the material on the river bed in the upper and lower courses of a river • a/ In the upper course load is smaller and more rounded than in the lower course because of erosional processes such as attrition and corrasion. • b/ As a river moves through its course, because of the greater incidence of larger settlements, more supermarket shopping trolleys are likely to be found in rivers, adding to the load that has already been deposited. • c/ In the lower course load is smaller and more rounded than in the upper course because of erosional processes such as attrition and corrasion.

3. 2/ P2F 2001 A river may erode by the processes of corrosion, attrition, corrasion or hydraulic power. For hydraulic power describe how it works • a/ This is when river water and its load are thrown against the river banks causing erosion. • b/ Water and air are forced into cracks on the river bank, exerting a pressure. When this process is repeated many times it causes erosion. • c/ A river carries large amounts of load that are constantly smashing into each other and breaking into smaller particles. This makes the load smaller and more rounded over time.

4. 3/ 1999 P2F Traction, saltation, suspension and solution are the 4 methods of transport of material along a river. For saltation explain how each it works • a/ small peebles bounce along the river bed. • b/ large boulders roll along the river bed. • c/ fine material is carried along, suspended in the water.

5. 4/ Give reasons for the differences in cross sections of rivers in the upper and lower courses • a/ In the upper course rivers are narrow and swallow because the river is less powerful and discharge relatively low. In the lower course the river is wider and deeper as the river carries more load, discharges more and has more power to erode. • b/ In the upper course rivers are wide and deep because the river is less powerful and discharge relatively low. In the lower course the river is narrow and shallow as the river carries more load, discharges more and has less power to erode. • c/ As a river moves from its upper to its lower course, it tends to carry more load, is wider, deeper, faster flowing and discharge increases.

6. 5/P3H 2001 explain the formation of a waterfall and gorge (6) • a/ Niagara Falls is one of the best known waterfalls in the world. There are actually two waterfalls together which have been formed as a gorge has worn down the Niagara river. Angel falls, in Venezuela is the biggest waterfall in the world. • b/ Sometimes water takes a short cut to the sea by going over a waterfall. A good example of a gorge is Ironbridge gorge, Shropshire. It has a fantastic iron bridge over the river Severn. • c/ If a river flows over hard rock which lies on top of exposed softer rock, the softer rock may be undercut by erosion, forming a waterfall. If the waterfall retreats upstream it can form a steep sided valley called a gorge.

7. 6/ What features are associated with waterfalls • a/ Niagara, Victoria, Angel, High Force. • b/ Plunge pool, undercutting, hard and soft rock. • c/ Weathering, erosion, transportation and deposition.

8. 7/ What river features and landforms are associated with a cross section or profile of a river valley in its upper course. • a/ river source, V-shape, interlocking spurs, narrow and shallow river channel. • b/ delta, flood plain, river mouth, levees, wide and deep river channel. • c/ sheep farming, wind turbines, HEP (hydro-electric power) stations and dams and reservoirs.

9. 8/ 1999 P2F of the following features are not formed by river deposition. • a/ levee • b/ gorge • c/ delta

10. 9/ What are meanders • a/ they are bends in a river formed by a river as the volume of water increases in its lower course. The shaping of a meander bend is helped by erosion on the outside of the bend and deposition on the inside of the bend. • b/ meanders migrate across their flood plain, widening the river valley and helping to form a flood plain. • c/ they are bends in a river.

11. 10/ P1H 2005 Explain how the features of a meander are formed (4) • a/ a river cliff forms on the inside of a river bend as a result of faster flowing water and its load causing erosion and undercutting the river bank. A slip off slope forms on the outside of a river bend where the river is flowing more slowly and deposition takes place. • b/ a river cliff forms on the outside of a river bend as a result of faster flowing water and its load causing erosion and undercutting the river bank. A slip off slope forms on the inside of a river bend where the river is flowing more slowly and deposition takes place. • c/ a river cliff forms on the outside of a river bend as a result of faster flowing water and its load causing deposition on the bank. A slip off slope forms on the inside of a river bend where the river is flowing more slowly and erosion takes place.

12. 11/ 1998 P3H & P1H Explain the formation of an ox bow lake. You may use diagrams to help you • a/ These lakes were dug out by farmers to provide fresh water for their cattle and oxen. • b/ These are formed when an alien head is guillotined by a river, leaving a horse shoe print. • c/ It forms where a river channel erodes through the neck of two meander bends that are eroding towards each other. The river then flows more directly and is diverted away form the meander bend. The neck is then sealed off from the rest of the river channel through deposition, leaving a arc shaped lake isolated from the rest of the river.

13. 12/ P3H 2000 Explain how a river flood plain is formed. • a/ These are formed in the upper course of a river. The river valley has a typical V shape and the river flows around ridges of land. • b/ Meanders migrate across a river valley due to erosion. This helps to wider out the valley forming a plain. When a river overflows its bank it floods its plain. As the flood waters retreat they deposit river load over the valley floor, helping to build up the flood plain through deposition. • c/ A river flood plain is the flat area of land either side of the river channel that is flooded when a river rises above its banks.

14. 13/ P2f 2002 Explain how levees are formed • a/ Levees have been built around New Orleans to stop the city from flooding. However, several levees gave way in August 2005 as New Orleans took a direct hit from hurricane Katrina. The levees surrounding New Orleans were not built to cope with a storm surge from a F4 hurricane. • b/ These are raised river banks on either side of the river channel. They can form naturally or can be heightened by humans as part of a river management strategy. • c/ The river banks on the sides of a river channel are heightened over time as a result of successive flooding of a river’s flood plain. As the flood waters retreat the frictional drag and slow moving water leads to further deposition of sediment on the banks.

15. 14/ P1H 2007 Identify 3 features of the lower course of a river • a/ waterfalls, sheep farming, large boulders. • b/ v-shaped valley, interlocking spurs, river source. • c/ flood plain, meander, delta.

16. 15/ Explain how a delta forms • a/ It forms at the mouth of a river, where the river meets the sea. The river and its load spread into the sea slowing down and depositing load. Over a period of time large amounts of load are deposited in a triangular pattern. The river may split into lots of channels because its course is diverted by deposition. These channels are called distributaries. • b/ This is where the fresh water of a river meets the salt water of the sea. They often make excellent harbours. When the tide goes out large areas of mudflats can be seen. • c/ It forms at the source of a river, where the river meets its valley. The river and its load spread into the valley speeding up and depositing load. Over a period of time large amounts of load are deposited in a circular shape. The river may split into lots of channels because its course is diverted by erosion. These channels are called tributaries.

17. 16/ Sp 3H Explain one disadvantage of the area of the upper course of a river for human activity • a/ There are fewer settlements. • b/ It is accessible. • c/ It is often more inaccessible.

18. 17/ P2f & 3H 2000 What factors affect the location of a reservoir • a/ A reservoir needs a ready supply of water, that can be easily transferred to consumers. The water should be stored securely and the flooding impact of creating a reservoir limited. • b/ These are walled in by dams that may produce HEP (hydro electric power) which help to contribute towards the energy requirements of a country. • c/ These are often close to large populations to supply households and businesses with water.

19. 18/ What is river discharge • a/ This is how a river responds to a period of rainfall. It is the amount of water that passes a point in a river over a period of time. It is measured in Cumecs (cubic metres per second). • b/ This is the height of the river. When it rains the river rises and then later returns to its base flow. • c/ This is shown on a hydrograph. It has a rising limb and a falling limb. It shows rainfall, including peak rain. It is also possible to calculate the lag time from the difference between peak rain and peak discharge.

20. 19/ Sp P2F Name two features which may affect the discharge of the River Severn • a/ The level of urbanisation in the area. • b/ The amount of industry in the area. • c/ The amount of rainfall and interception by vegetation

21. 20/ P2F 2001 How long is the lag time shown on the hydrograph • a/ 8 hours 30 mins • b/ 9 hours 30 mins • c/ 10 hours 30 mins

22. 21/ P2F and P3H 2001 Using the hydrograph, how much water did the river carry before it began to flood • a/ 40 mm • b/ 40 metres • c/ 40 cumecs Above this level of discharge and flooding will occur

23. 22/ P3H 2001 Using the hydrograph, how many hours was the river in flood • a/ about 1 hour • b/ about 3 hours • c/ about 5 hours Above this level of discharge and flooding will occur

24. 23/ Which of the following river catchment variables will speed up river discharge • a/ a dam • b/ afforestation • c/ urbanisation

25. 24/ P2F 2002 &P3H suggest 2 possible causes of river flooding • a/ A prolonged period of heavy rain and increased building on the flood plain so that discharge to rivers is increased. • b/ Failure of the levees eg. New Orleans, August 2005. • c/ A tropical cyclone may be funnelled through the Bay of Bengal which causes a storm surge and floods Bangladesh.

26. 25/ P1F & P1H 2004 Describe the causes of a river flood that you have studied • a/ Dams have been built, levees have been heightened, flood storage reservoirs built. Some of the Mississippi’s tributary rivers have had part of their catchment areas afforested. • b/ Mississippi Floods of 1993. Spring snow melt together with 50 days of heavy rain in the Mid West. Building on the floodplain has increased runoff and added to the pressure the levees were under. They were built only to withstand a limited amount of discharge and eventually they gave way. • c/ New Orleans Flood of 2005. Loss of lives, homes and livelihoods. Estimated 500,000 displaced people. People injured and ill. Some people looted and America’s reputation was damaged.

27. 26/ 1998 P3H Using the resource (not provided), suggest 2 ways the flooding in Chichester had an impact upon the local economy • a/ damage to farmers crops and the large bill to clear up the flood damage for the council • b/ schools were closed, so that students could not attend lessons and hand in their homework • c/ A mother from the local area, on a trip into Chichester, found herself and her 5 children stuck in 2 metres of water

28. 27/ P2F & P3H 2001 Using an example describe the effects of a flood • a/ The Chichester floods of 1994. Damage to property, communications cut off and damage to crops. • b/ New Orleans Flood of 2005. Loss of lives, homes and livelihoods. Estimated 500,000 displaced people. People injured and ill. Some people looted from businesses and America’s reputation was damaged. • c/ Mississippi floods of 1993. 28 lives lost and 10$ billion repair costs.

29. 28/ P1f & 1H 2003 Using an example of a flood in an MEDC, describe its effects on the land and people • a/ Flooding in Bangladesh 1988; 2400 people killed and a large part of the country flooded (upto 80% at one time). Infrastructure and homes were damaged and crops were lost. 25 million people were made homeless. Water supply was contaminated so hospitals were inundated with cases of dysentery, diarrhoea and cholera. • b/ Mississippi floods of 1993; 28 lives lost, 36,000 people were made homeless and evacuated. Transport was restricted and crops were loss.10$ billion was needed to repair the flood damage and millions of tonnes of silt and sand were deposited in the flood zone. • c/ Mississippi Floods of 1993. Spring snow melt together with 50 days of heavy rain in the Mid West. Building on the flood plain has increased runoff and added to the pressure the levees were under. They were built only to withstand a limited amount of discharge and eventually they gave way.

30. 29/ P2F 2002 &P3H suggest 2 ways settlements could be protected from flooding in the future • a/ Countries could reduce their emissions of carbon dioxide thereby reducing the risk of the ice caps melting and thus flooding occurring. • b/ Build levees and flood relief channels. • c/ Countries could build expensive dams, dredge river beds and increase river channel capacity or plant trees in large areas of a river’s catchment to reduce river discharge.

31. 30/ 2004 Explain the advantages that the river restoration scheme may bring to the area • a/ The river is dredged of its sediments, increasing river channel capacity and providing sand for local beaches and building. • b/ Few river restoration schemes have been introduced since most people prefer the reliability of hard engineering constructions to protect their properties from flooding. • c/ The river is allowed to flood naturally, so that costly hard engineering is unnecessary and the flood damage less severe in the long term. River wildlife ecosystems return.

32. 31/ P1H 2005 Flood plain zoning is a soft management strategy. What does a soft management strategy mean • a/ It is a method of river flood management which involves major construction work eg. flood plain zoning • b/ It is a method of river flood management which works or attempts to work with natural river processes. It does not tend to involve major construction work eg. flood plain zoning • c/ It is an easy and cheap form of river management strategy. For example using sandbags to prevent flooding

33. 32/ P1F 2005 which of the following are examples of soft river engineering • a/ Dredging and flood relief channels. • b/ Dams and levees. • c/ River restoration and land use zoning.

34. 33/ P1H 2005 Using the diagram (not provided), describe the flood plain zoning and explain why strategies such as this are sustainable • a/ This is soft engineering. This involves using planning laws to control building on flood plains. Its advantage is that it is cheap, but requires sufficient prediction and investigation into the possibilities of flooding. • b/ Flood plain zoning - This is soft engineering. It involves using planning laws to control building on flood plains. This is seen as sustainable because not only does it reduce the impact of flooding, because building damage is limited, but because the flood plain has not been built upon, surface runoff to river discharge is less likely to cause flooding. Furthermore, flood plain zoning and other soft engineering strategies such as afforestation and river restoration can be seen as sustainable because they are cheaper and have less impact on the environment. Many believe that some hard engineering strategies are less sustainable because they are expensive and make flooding worse. Eg raising the levees – if flooding occurs it is far worse. Channel dredging may need to take place on a regular basis to maintain river channel depth as well as the dredging behind dams to maintain storage capacity. • c/ Flood plain zoning - This is hard engineering. It involves using planning laws to build on flood plains. This is seen as unsustainable because it increases the impact of flooding. Furthermore, flood plain zoning and other hard engineering strategies such as afforestation and river restoration can also be seen as unsustainable because they are cheaper and have more impact on the environment. Many believe that some soft engineering strategies are sustainable because they are expensive and make flooding worse. Eg raising the levees – if flooding occurs it is far worse. Channel dredging may need to take place on a regular basis to maintain river channel depth.