5 - River Basin Hydrology

Question 1

Rivers

Answer 1

naturally flowing water courses

Question 2

Precipitation

Answer 2

water vapour that falls from the clouds due to gravitational pull

Question 3

What are the main types of precipitation?

Answer 3

Convectional, orographic (important for rivers) and cyclonic

Question 4

Drainage basin

Answer 4

ll flowing surface water converges to a single point, such as a river mouth or flows into another body of water, e.g. lake or ocean
Amazon is the largest river basin (7 million km2)

Question 5

Perennial river

Answer 5

uninterrupted flow of water regardless of season

Question 6

Intermittent river

Answer 6

occasionally cease to flow (every year or 2/5 years)

Question 7

Ephemeral

Answer 7

only flow when heavy rainfall

Question 8

What are the most intermittent rivers?

Answer 8

Small rivers where there are only pulses of rain or glacial melt

Question 9

Method of classifying rivers?

Answer 9

Strahler stream order
Amazon most complex and has max score (9)

Question 10

Anastomosing rivers

Answer 10

similar to braided but have vegetated islands

Question 11

what determines drainage pattern?

Answer 11

• Rock type/ grain size
• Slope
• Stream power = amount of energy in a river

Question 12

River discharge

Answer 12

volume of water flowing through a river channel (m3/s)

Question 13

How is river discharge measured?

Answer 13

1. Current meter = measure w and d of each subsection and measure V using a current meter (looks like rotating plastic thing). Can be fixed. Old but still used.
2. ADCPs = determine water velocity by sending sound pulses into the water. Often installed on passenger ships to get frequent measurements

Question 14

Fluvial floods

Answer 14

when water rises above riverbanks. Often annual but can be every 100/1000 years

Question 15

Flash flood

Answer 15

rapid flooding of low lying areas typically caused by heavy rainfall

Question 16

Dams

Answer 16

a barrier that stops or restricts the flow of surface waters or underground streams
- Control water and sediment flow (often halt sediment from reaching coastal zone)
- Reduces sediment in rivers leading to instability and erosion of coastal deltas
Geopolitical issue

Question 17

Sluices

Answer 17

moveable gate that controls water flow, levels and velocities (water gate)

Question 18

Canals

Answer 18

waterways or engineered channels built for drainage management *e.g. flood control or irrigation) or for conveying water transport

Question 19

Dikes

Answer 19

barrier used to regulate or hold back water from a river, lake or ocean.

Question 20

Groynes

Answer 20

shore protection structure built perpendicular to the shoreline in order to reduce longshore drift and trap sediments

Question 21

Why was Rhine straightened?

Answer 21

More flood control, less swamps and malaria, more agricultural land, navigation and regional development