Storm hydrograph

Question 1

Time

Answer 1

The measure of the duration of the rainfall event

Question 2

Precipitation

Answer 2

Rainfall

Question 3

Peak precipitation

Answer 3

The greatest rainfall during the rainfall event

Question 4

Rising limb

Answer 4

Rising river discharge after rainfall event

Question 5

Lag time

Answer 5

The time between peak rainfall and peak discharge

Question 6

Peak discharge

Answer 6

Maximum river discharge during rainfall event

Question 7

Falling limb

Answer 7

Period of time where discharge is decreasing

Question 8

Groundwater flow

Answer 8

Average river discharge

Question 9

Storm flow

Answer 9

Discharge of river above base flow caused by rainfall event

Question 10

Bankfull level

Answer 10

The maximum volume of water held before a flood event

Question 11

Basin size, shape, relief

Answer 11

Bigger basins have longer lag times generally

Question 12

Precipitation type

Answer 12

Prolonged rainfall leads to most floods
Intense storms result in flash floods
Snowfall results in a long lag time but high peak discharge

Question 13

Temperature

Answer 13

Extremes of temperature increase surface runoff

Question 14

Land use

Answer 14

Vegetated land increases interception

Urbanisation increases surface runoff

Question 15

Geology

Answer 15

Permeable rock allows percolation

Permeable rock can be porous or pervious

Question 16

Soil type

Answer 16

Controls rate and volume of infiltration and related processes/stores

Question 17

Drainage density

Answer 17

The number of surface streams in an area

More streams means more likely flash floods

Question 18

Tides and storm surges

Answer 18

High tide prevents receding floods

High tide plus gale force winds cause storm surge