Week 2: River Flow, Floods and Runoff

Question 1

Surface flow

Answer 1

Precipitation which is not absorbed by the soil and flows on the ground surface.

Question 2

Runoff

Answer 2

Runoff (m3/day) = runoff coefficient x rainfall (m/day) x area (m2)

Question 3

Rating curve

Answer 3

A rating curse is constructed by plotting successive measurements of discharges and gage height (water stage).

Question 4

Stream cross section

Answer 4

A cross section of a stream, usually given in m2.

Question 5

Velocity-Area method

Answer 5

A method of estimating discharge. It is the product of the average velocity of the cross sectional areas (m/s) and the area of the cross section (m2).

Question 6

Swoffer

Answer 6

Device used to measure the velocity of moving water.

Question 7

Bankflow

Answer 7

Flow conveyed in a water course without overtopping the banks.

Question 8

Flood

Answer 8

Relatively high water levels that overtop the natural or artificial banks of a water body.

Question 9

Floodplain

Answer 9

An area of low lying-lying ground adjacent to a river that is subject to flooding.

Question 10

Return period

Answer 10

The average recurrence interval between events equalling or exceeding a threshold.

Question 11

Floodplain Risk Analysis

Answer 11

Identification and mapping of flood hazard areas