Ch 8 Geology Exam Questions And Answers
Hydrolic cycle
Continuous movement of water from the oceans to the atmosphere and then from the atmosphere to
the land and then from the land back to sea
How is the precipitation that falls on the land calculated
The sum total of evaporation, transpiration, runoff and infiltration
Transpiration
The release of water vapor by vegetation
Infiltration
A portion of precipitation that falls on land that soaks into the ground
Runoff
When the rate of rainfalls exceeds the ability of the surface to absorb it (infiltration)
Rills
Run off that initially flows in broad sheets form these tiny channels
What happens to rills
They merge to form gullies which eventually join to create streams
Erosion in hydrologic cycle
Wears down the land and shapes earths surface
What do factors such as climate, steepness of slope, surrounding material, vegetation and degree of
urbanization produce
local variation in the globally uniform exchange of water balance
Globally, from which source does more water evaporate into the atmosphere, ocean or land?
ocean
Percentage from oceans =
Ocean evaporation/ total evaporation
Apprx, what percentage of the total water evaporated into the atmosphere comes from the ocean
84.2%
If the sea level is not dropping, what is a source of water for the oceans in addition to precipitation
Runoff
Worldwide, about how much of the precipitation that falls on the land becomes runoff
, 35%
What happens to much of water that falls on land
It doesn't immediately return to the ocean via runoff. Instead it is temporarily stores in reservoirs
such as lakes
What happens to most of the water that reaches the land surface
It will infiltrate or run off
What is the balance between infiltration and runoff influenced by
Factors such as the permeability of the surface material, slope of the land, intensity of the rainfall and
type and amount of vegetation.
When does runoff occur on the surface
When the ground becomes saturated, that is when it contains all the water it can hold
Hydrographs
Plots of streamflow, or runoff, over time
What is runoff measured by
stream discharge
stream discharge
The volume of water flowing past a given point per unit of time usually measured in cubic feet per
second
Does urbanization increase or decrease the peak streamflow
increASE
Peak flow
Potential flood
Lag time
The span between when rainfall occurred and when peak stream discharge occurred
What is the effect of urbanization on lag time
Decreases
Does total runoff occur over a longer or shorter time span after an area has been urbanized
Runoff occurs over a shorter time after urbanization
Why do urban areas ofter experience more flash flooding than do rural areas during intense rainfalls
Because of the building covering the surface there is a longer time for the water to be infiltrated so it
builds up and causes excess of surface water aka flooding
Hydrolic cycle
Continuous movement of water from the oceans to the atmosphere and then from the atmosphere to
the land and then from the land back to sea
How is the precipitation that falls on the land calculated
The sum total of evaporation, transpiration, runoff and infiltration
Transpiration
The release of water vapor by vegetation
Infiltration
A portion of precipitation that falls on land that soaks into the ground
Runoff
When the rate of rainfalls exceeds the ability of the surface to absorb it (infiltration)
Rills
Run off that initially flows in broad sheets form these tiny channels
What happens to rills
They merge to form gullies which eventually join to create streams
Erosion in hydrologic cycle
Wears down the land and shapes earths surface
What do factors such as climate, steepness of slope, surrounding material, vegetation and degree of
urbanization produce
local variation in the globally uniform exchange of water balance
Globally, from which source does more water evaporate into the atmosphere, ocean or land?
ocean
Percentage from oceans =
Ocean evaporation/ total evaporation
Apprx, what percentage of the total water evaporated into the atmosphere comes from the ocean
84.2%
If the sea level is not dropping, what is a source of water for the oceans in addition to precipitation
Runoff
Worldwide, about how much of the precipitation that falls on the land becomes runoff
, 35%
What happens to much of water that falls on land
It doesn't immediately return to the ocean via runoff. Instead it is temporarily stores in reservoirs
such as lakes
What happens to most of the water that reaches the land surface
It will infiltrate or run off
What is the balance between infiltration and runoff influenced by
Factors such as the permeability of the surface material, slope of the land, intensity of the rainfall and
type and amount of vegetation.
When does runoff occur on the surface
When the ground becomes saturated, that is when it contains all the water it can hold
Hydrographs
Plots of streamflow, or runoff, over time
What is runoff measured by
stream discharge
stream discharge
The volume of water flowing past a given point per unit of time usually measured in cubic feet per
second
Does urbanization increase or decrease the peak streamflow
increASE
Peak flow
Potential flood
Lag time
The span between when rainfall occurred and when peak stream discharge occurred
What is the effect of urbanization on lag time
Decreases
Does total runoff occur over a longer or shorter time span after an area has been urbanized
Runoff occurs over a shorter time after urbanization
Why do urban areas ofter experience more flash flooding than do rural areas during intense rainfalls
Because of the building covering the surface there is a longer time for the water to be infiltrated so it
builds up and causes excess of surface water aka flooding
