Mock

Question 1

15 marker - is climate most significant

Answer 1

Climate:

Precipitation type:

Rain will increased discharge quickly, whereas snow will delay the impact

Precipitation intensity:

When intensity exceeds infiltration capacity = overland flow and so rapid rises in discharge

Temperature:

• in equatorial climate may have constant annual pattern and so constant discharge levels

Tropical climate such as the amazon basin, high levels of precipitation contribute to high discharge rates

Antecedent moisture/climate:

Affect soils infiltration capacity

Other factors:

Topography:

mountainous regions like the Himalayas, steep slopes and high elevations influence discharge patterns. Precipitation falling on these slopes can quickly generate runoff, leading to flashy hydrographs with rapid rises and falls in river discharge

Land use:

urbanized drainage basins, impervious surfaces such as roads, buildings, and parking lots can increase surface runoff and alter discharge patterns

e.g Bangladesh

Question 3

Define infiltration and interception

Answer 3

• Infiltration refers to the process by which water from precipitation, irrigation, or surface runoff enters and penetrates into the soil surface and moves downward through the soil profile
• Interception refers to the process by which precipitation is captured and retained by vegetation, litter, and other surfaces before it reaches the ground or other surfaces below.

Question 4

Describe a river levee

Answer 4

• natural/artificial embankments found parallel to the river
• formed during flooding by deposition of heavier sediments as floodwater comes out of the river channel
• example: Mississipi River levee system

Question 5

Explain the formation of meanders and oxbow lakes

Answer 5

meander:
- the velocity of water is higher on the outside of the bend.
- increased velocity leads to greater erosion along the outer bank
- Hydraulic action, abrasion, and undercutting by turbulent flow = erosion.
- velocity of water is slower on inside of the bend= deposition
- reduced velocity allows sediment to be deposited on the inner bank (point bar) of the meander loop.
- occurs due to decreased energy levels, allowing finer particles carried by the river to settle out and accumulate.
- over time continuous erosion results in lateral migration

Oxbow lake:
- As meander loop continues to migrate laterally, the neck of land between the adjacent meander bends becomes narrower.
- Erosion on outside of the meander bend progresses, while deposition continues on the inside, causing the neck of land to narrow further.
- during times of flood water may erode the neck
- Once the river has cut through the neck of land, it follows the shorter, straighter path, bypassing the original meander
- abandoned meander loop is then isolated from the main river channel - oxbow lake