rivers

Question 1

what is a levee and how is it formed?

Answer 1

a raised embankment on either side of a river to prevent flooding

formed through deposition, large material is dropped first which slows water down.

Question 2

drainage basin

Answer 2

an area drained by a river and its tributaries

Question 3

PISS IS PG

Answer 3

Precipitation
Interception
Stem-flow
Surface Storage
Infiltration
Soil moisture
Percolation
Groundwater storage

Question 4

explain the formation of a flood plain

Answer 4

a flat area of land adjacent to a river, it is covered in water at times of flood
wide=erosion on outer banks of meander
flat=repeated deposition of alluvium
levee=raised bank at the edge of the river

Question 5

water cycle

Answer 5

the continuous circulation of water of evaporation from the sea, through the air and back to the sea by flowing through rivers or the ground.

Question 6

precipitation

Answer 6

INPUT. any water falling from the sky: rain, hail, sleet, snow

Question 7

Interception,

Answer 7

STORE. where water is prevented from reaching the ground by vegetation. it can slow run-off and reduce the risk of flooding.

Question 8

watershed

Answer 8

the boundary between two drainage basins. usually a ridge of high land.

Question 9

tributary

Answer 9

a smaller river flowing into a larger river

Question 10

confluence

Answer 10

a place where two streams / rivers meet.

Question 11

mouth

Answer 11

where a river flows into the sea.

Question 12

evapotransporation

Answer 12

OUTPUT. Water turning from liquid into gas (water vapour) in the air by plants through their leaves.

Question 13

gradient

Answer 13

the steepness of the slope down which a river flows. it will usually become less steep from source to mouth.

Question 14

load

Answer 14

material carried/transported by a river e.g rocks, pebbles, sand, mud.

Question 15

discharge

Answer 15

the amount of water passing a point in a river every second. measured in cumecs or cubic metres per second.

Question 16

types of erosion

Answer 16

attrition (the load hit against each other and become smaller and fine)
hydraulic action(force of moving water)
abrasion/corrasion(load carried by a river grinds against the bed and banks of the river
corrosion(water dissolves minerals in the rock)

Question 17

types of transportation

Answer 17

traction(largest material are rolled along the river bed)
saltation(pebbles bounce along the river bed)
suspension(small material are carried along in the water)
solution(rocks are dissolved into river water)

Question 18

Land use zonation

Answer 18

soft engineering strategy to designate high flood risk areas not to be built on and others to be forested to increase interception.

Question 19

how is a meander formed?

Answer 19

centrifugal forces push most of the water to the outside this creates fast flowing water
this creates erosion (hydraulic action)
this erosion is responsible for creating a river cliff on the inside of the bend there is less water and the water flows slowly. this creates deposition and a shallow river bed and a feature called slip-off-slope

Question 20

how is a waterfall formed?

Answer 20

water flows over an area of hard rock and soft rock. the soft rock is eroded first due to hydraulic action and abrasion. this treated a step in the river. the soft rock continues to erode and undercuts the hard rock creating an overhang. the overhang is unsupported and it collapses into a plunge pool. overtime this process continues and retreats back and creates a gorge.