1.2 Discharge Relationships

Question 1

What is a Storm Hydrograph?

Answer 1

A graph showing changes in river discharge over a short period, typically in response to a storm event.

Question 2

What is a Flashy Hydrograph?

Answer 2

A hydrograph with a short lag time and steep rising and falling limbs, usually indicating a high flood risk.

Question 3

What is a Subdued Hydrograph?

Answer 3

A hydrograph with a long lag time and gentle rising and falling limbs, indicating slower water movement.

Question 4

Define Peak Discharge

Answer 4

The maximum amount of river discharge recorded after a rainfall event.

Question 5

Define Bankfull Discharge

Answer 5

The maximum amount of water a river channel can hold before it floods.

Question 6

Define Lag Time

Answer 6

The delay between peak rainfall and peak river discharge.

Question 7

Define Rising Limb

Answer 7

The part of a hydrograph where discharge increases following rainfall.

Question 8

Define Falling Limb

Answer 8

The part of a hydrograph where discharge decreases after peak flow.

Question 9

Linking to infiltration, Why is land use a factor affecting the shape of a storm hydrograph?

Answer 9

In urban area with more concrete there is less infiltration which leads to more surface run-off and a more flashy storm hydrograph

Question 10

Linking to infiltration, Why is rock type a factor affecting the shape of a storm hydrograph?

Answer 10

The more impermeable a rock is there is less infiltration which leads to more surface run-off and a more flashy storm hydrograph

Question 11

Linking to interception, Why is vegetation a factor affecting the shape of a storm hydrograph?

Answer 11

The less vegetation cover leads to less interception which leads to more surface run-off and a more flashy storm hydrograph

Question 12

Linking to infiltration, Why is soil a factor affecting the shape of a storm hydrograph?

Answer 12

The less saturated and more dry the soil is the less infiltration which leads to more surface run-off and a more flashy storm hydrograph

Question 13

Linking to infiltration, Why is relief a factor affecting the shape of a storm hydrograph?

Answer 13

The more steep the relief is there is less infiltration which leads to more surface run-off and a more flashy storm hydrograph

Question 14

Linking to infiltration, Why is drainage density a factor affecting the shape of a storm hydrograph?

Answer 14

The higher the density of drainage basin, the less infiltration which leads to more surface run-off and a more flashy storm hydrograph