storm hydrographs

Question 1

what is a river regime

Answer 1

A river regime shows the annual pattern of discharge in a river.

Question 2

what is noticeable in a river regime

Answer 2

The discharge can vary in response to precipitation, temperature, evapotranspiration and drainage basin characteristics.

Question 3

what is lag time

Answer 3

time between peak rainfall and peak discharge

Question 4

Describe the characteristics of the hydrograph for the undisturbed forest (4 marks)

Answer 4

Fast or slow response river?
Steep or shallow rising limb?
How long is the lag time? – Is that long or short?
How much is the peak discharge? – Is that high or low?

Question 5

Suggest 2 possible reasons for the differences between the two hydrographs (4 marks)

Answer 5

slopes and interception

Question 6

Describe the characteristics of the hydrograph for the undisturbed forest (4 marks)

Answer 6

Slow response river
Shallow rising limb
Long lag time of 100 minutes
Low peak discharge of 1.0 cumecs

Question 7

Suggest 2 possible reasons for the differences between the two hydrographs (4 marks)

Answer 7

Mountain farm has steep slopes (water runs of quickly into river, hence the short lag time)
Undisturbed forest enables high interception of rainfall (water held on leaves or in roots) slowing and preventing the flow of water into the river, increasing the lag time and giving a lower peak flow.