Rivers Flashcards

Question

check book for river transport porcesses.

Answer 1

-Solution minerals are dissolved in the water , this affects soft rocks such as limesone and chalk . Load transported in this way is called solute load . Suspension - fine light material is held up and carried wihin the rivers flow . This is called suspended load . Saltation - small pebbles and stones are bounc The load is alternately lifed then dropped in line with a local rise and fall in the velocity of the water Traction - large boulders and rocks re rolled along the river bed . Load carried in this way is called bedload.

Answer 2

msotly has vertical eriosion by hydruaic action tration large boulders depostied large boudlers hih relief steep gradeint waterfaal rapid .

Answer 3

less verical eriosin more lateral eriosn atrition abrasion and solution load trapsorited by suspension as laod is smaller depostioed on meanders hilly mounynioud . fidvhstgr invtrsdrf .

Answer 4

evry little erisoin onl lateral eriosn mostly suspensiona nd solutoin sml particles of load . depositon now fluvial fin mterial deopstied closes to rer mouth eriosn now confiend to lateral eriosn in meanders , flat gradient . dischrge i he volume of water pasing thoruh a given point on the river .

Answer 5

A waterfall is a sudden drop along the river course. It forms when there are horizontal bands of resistant rock (hard rock) positioned over exposed, less resistant rock (soft rock). The soft rock is eroded quicker than the hard rock and this creates a step. As erosion continues, the hard rock is undercut forming an overhang. Abrasion and hydraulic action erode to create a plunge pool. Over time this gets bigger, increasing the size of the overhang until the hard rock is no longer supported and it collapses. This process continues and the waterfall retreats upstream. A steep-sided valley is left where the waterfall once was. This is called a gorge.

Answer 6

In the upper course there is more vertical erosion. The river cuts down into the valley. If there are areas of hard rock which are harder to erode, the river will bend around it. This creates interlocking spurs of land which link together like the teeth of a zip

Answer 7

Due to erosion on the outside of a bend and deposition on the inside, the shape of a meander will change over a period of time. Erosion narrows the neck of the land within the meander and as the process continues, the meanders move closer together. When there is a very high discharge (usually during a flood), the river cuts across the neck, taking a new, straighter and shorter route. Deposition will occur to cut off the original meander, leaving a horseshoe-shaped oxbow lake.

Answer 8

A floodplain is an area of land which is covered in water when a river bursts its banks. Floodplains form due to both erosion and deposition. Erosion removes any interlocking spurs, creating a wide, flat area on either side of the river. During a flood, material being carried by the river is deposited (as the river loses its speed and energy to transport material). Over time, the height of the floodplain increases as material is deposited on either side of the river.

Answer 9

Levees occur in the lower course of a river when there is an increase in the volume of water flowing downstream and flooding occurs. Sediment that has been eroded further upstream is transported downstream. When the river floods, the sediment spreads out across the floodplain. When a flood occurs, the river loses energy. The largest material is deposited first on the sides of the river banks and smaller material further away. After many floods, the sediment builds up to increase the height of the river banks, meaning that the channel can carry more water (a greater discharge) and flooding is less likely to occur in the future.

Answer 10

An estuary is where the river meets the sea. The river here is tidal and when the sea retreats the volume of the water in the estuary is reduced. When there is less water, the river deposits silt to form mudflats which are an important habitat for wildlife.

Answer 11

Rapids are areas of shallow, fast-flowing water in a stream. when the water goes from one hard rock that resists the water's erosion to a softer rock that is easier eroded

Answer 12

The dam traps water, which builds up behind it, forming a reservoir. Water can be released in a controlled way. adv-Can be used to produce electricity by passing the water through a turbine within the dam. Reservoirs can attract tourist disadv-Very expensive. Dams trap sediment which means the reservoir can hold less water. Habitats are flooded often leading to rotting vegetation. This releases methane which is a greenhouse gas.

Answer 13

Straightening the river speeds up the water so high volumes of water can pass through an area quickly. Dredging makes the river deeper so it can hold more water. Advantages More water can be held in the channel. It can be used to reduce flood risk in built-up areas. Disadvantages Dredging needs to be done frequently. Speeding up the river increases flood risk downstream.

Answer 14

floodwarnigns and preparations - montioring so people can be preapred using sellites nd tv. People have time to protect their properties, eg with sandbags. Many possessions can be saved, resulting in fewer insurance claims. Disadvantages Some people may not be able to access the warnings. Flash floods may happen too quickly for a warning to be effective. They do not stop la

Answer 15

Allowing only certain land uses on the floodplain reduces the risk of flooding to houses and important buildings. More expensive buildings and land uses are further away from the river, so have a reduced flood risk. Less damage is caused, leading to fewer insurance claims. Disadvantages Not always possible to change existing land uses. Planners have to decide what type of flood to plan fo

Answer 16

Physical cause a stepepr releif means that therei s more runoff into the river compared to a flttr rellief which is wider so slower runoff .

Answer 17

More impermeable rock causes more runoff s water cannot be absorred , -Compred t permeable rock as mroe water is absored so less run off .

Answer 18

More saturated soi as thin layer of soil less through flow l , means more runoff les water is being absorbed . Thick layer of soil means more though fow .

Answer 19

vegetation mena sinterceptoopom od wayer as water is abroebd by the roots of th eplant os less run off . Not a lot of vegetation , nothing can intercept the water so mroe run off

Answer 20

Urbanisaition like (tarmax) increases the impermebale layer . Compared to rural areas , llittle armaxc more tree crop sin farming , so omre interception of wayer in increased irrigation .

Answer 21

Limitied use of river so all the water stays in the channne . -Wter used for industry , dams built water either extracted frp river or flow is restricted .

Answer 22

Higher density - mroe streams and tirbutaries to collect eater from land to chaneel into rivver . Lower denisu fewer streams to collect water or more the for water to be increased or infilitrated , slowign journery into channel .