Chp 8 Rivers, Water, streams

Question 2

What are the processes involved in Earth’s hydrological cyle?

Answer 2

• Precipitation
• Evaporation
• Infiltration
• Runoff
• Transpiration

Question 3

What is the inflitration capacity controlled by?

Answer 3

• intensity of rainfall
• prior wetted conditon of the soil
• soil texture
• slope of the land
• nature of the vegetative cover

Question 4

What is a drianage basin?

Answer 4

It is a land area contributing water to the stream.

Question 5

What are Drainage Patterns?

Answer 5

• Dendritic: develops on highly uniform bendrock.
  Has the shape of a tree.
• Rectabgular:
  Develops on highly jointed bedrock.
• Trevllis Pattern:
  Develops in areas of alternating weak and resistant bedrock.
• Radial:
  develops on isolated volcanic cones or domes.

Question 6

How can a stream lengthen its course?

Answer 6

• By building a delta
• By headward erosion

Question 7

What is water gap?

Answer 7

it is a notch where a river cuts through a ridge that lies in this path.

Question 8

What are the two types of flow?

Answer 8

• Laminar Flow
• Turbelent Flow

Question 9

What are the factors that effect the velocity fo flow?

Answer 9

• Gradient
• Channel characters including shape, size and roughness

Question 10

Area / perimeter ratio

Answer 10

It is a ratio used to find velocity. The higher the ratio, the faster the flow.

Question 11

What is discharge?

Answer 11

The volume of water moving past a given point in a certain period of time.

Question 12

What is the profile of a stream?

Answer 12

It is a cross-sectional view of a stream.
It is viewed from the source to the mouth.

Question 13

What increases from upstream to downstream?

Answer 13

• Velocity
• Discharge
• Channel size

Question 14

what deccreases from upstream to downstream?

Answer 14

• The gradient
• The roughness

Question 15

What is stream erosion?

Answer 15

Lifting loosely consolidated particles by abrasion or dissolution.

Question 16

Describe the lag-time difference between urban and non-urban areas.

Answer 16

Urban areas have a smaller lag time. This is because concrete and the pavement don’t absorb the water. This contributes to flooding as a greater amount is discharged in a shorter time.

Question 17

What are factors that cause flooding

Answer 17

There are natural and human factors

Question 17

What are the 2 types of stream valleys and how is each one formed?

Answer 17

• Narrow valleys:
  V-shaped
  Downcutting towards the base level
  features often include rapids and waterfalls
• Wide valleys:
  The stream is near the base level.
  Downward erosion is less dominant
  Stream energy is directed from side to side forming a floodplain.