CPESC Erosion Prediction (RUSLE and
MUSLE)
What is sediment yield - CORRECT ANSWER-the amount of eroded soil that is
delivered to a point in the watershed that is remote from the origin of the
detached soil particles
Sediment yield does not include _______________? - CORRECT ANSWER-the
sediment that is deposited after it is eroded but before it reaches the point of
interest in the watershed.
Do RUSLE and USLE estimate sediment yield? - CORRECT ANSWER-NO
What does RUSLE stand for? - CORRECT ANSWER-Revised Universal Soil
Loss Equation
What do both the RUSLE and USLE compute? - CORRECT ANSWER-the
annual erosion expected on field slopes
What is the RUSLE equation? - CORRECT ANSWER-A=RxKxLxSxCxP
What does the "A" stand for in the RUSLE formula? - CORRECT
ANSWER-spatial average soil loss and a temporal average soil loss per unit of
area. Expressed in the units selected for K and the period selected for R.
(generally expressed as tons per acre per year)
What does the "R" stand for in the RUSLE formula? - CORRECT
ANSWER-rainfall-runoff erosivity factor (rainfall index plus a factor for any
significant runoff from snow melt)
What does the "K" stand for in the RUSLE formula? - CORRECT ANSWER-soil
erodibility factor (the soil loss rate per erosion index unit for a specified soil)
What does the "L" stand for in the RUSLE formula? - CORRECT ANSWER-slope
length factor (ratio of soil loss from the field slope length compared to a standard
length of 72.6 ft under identical conditions)
, What does the "S" stand for in the RUSLE formula? - CORRECT ANSWER-slope
steepness factor (the ratio of soil loss from the field slope compared to a 9%
slope under identical conditions)
What does the "C" stand for in the RUSLE formula? - CORRECT
ANSWER-cover management factor (the ratio of soil loss from an area with
specified cover and management to soil loss from an identical area in bare
condition)
What does the "P" stand for in the RUSLE formula? - CORRECT
ANSWER-erosion control practice factor (the ratio of soil loss with a certain
conservation practice to that of no practice)
On a long uniform slope, how does the erosion on the top half generally differ
from the bottom half? - CORRECT ANSWER-The top erosion is generally much
lower than the bottom
Soil loss equations are significantly less accurate for which type of events? -
CORRECT ANSWER-Specific weather events
Soil loss equations are most accurate at predicting the average soil loss over the
_________________? - CORRECT ANSWER-Long term
USLE formula can be used for estimating soil loss from what condition which
RUSLE cannot? - CORRECT ANSWER-disturbed forested conditions
The "R" factor is best found through obtaining it directly from ______? -
CORRECT ANSWER-maps
The erosion index developed by _________________ currently seems to provide
the most accurate "R" values - CORRECT ANSWER-Wischmeier
A map showing "R" values is called a ________________? - CORRECT
ANSWER-Isoerodent map
MUSLE)
What is sediment yield - CORRECT ANSWER-the amount of eroded soil that is
delivered to a point in the watershed that is remote from the origin of the
detached soil particles
Sediment yield does not include _______________? - CORRECT ANSWER-the
sediment that is deposited after it is eroded but before it reaches the point of
interest in the watershed.
Do RUSLE and USLE estimate sediment yield? - CORRECT ANSWER-NO
What does RUSLE stand for? - CORRECT ANSWER-Revised Universal Soil
Loss Equation
What do both the RUSLE and USLE compute? - CORRECT ANSWER-the
annual erosion expected on field slopes
What is the RUSLE equation? - CORRECT ANSWER-A=RxKxLxSxCxP
What does the "A" stand for in the RUSLE formula? - CORRECT
ANSWER-spatial average soil loss and a temporal average soil loss per unit of
area. Expressed in the units selected for K and the period selected for R.
(generally expressed as tons per acre per year)
What does the "R" stand for in the RUSLE formula? - CORRECT
ANSWER-rainfall-runoff erosivity factor (rainfall index plus a factor for any
significant runoff from snow melt)
What does the "K" stand for in the RUSLE formula? - CORRECT ANSWER-soil
erodibility factor (the soil loss rate per erosion index unit for a specified soil)
What does the "L" stand for in the RUSLE formula? - CORRECT ANSWER-slope
length factor (ratio of soil loss from the field slope length compared to a standard
length of 72.6 ft under identical conditions)
, What does the "S" stand for in the RUSLE formula? - CORRECT ANSWER-slope
steepness factor (the ratio of soil loss from the field slope compared to a 9%
slope under identical conditions)
What does the "C" stand for in the RUSLE formula? - CORRECT
ANSWER-cover management factor (the ratio of soil loss from an area with
specified cover and management to soil loss from an identical area in bare
condition)
What does the "P" stand for in the RUSLE formula? - CORRECT
ANSWER-erosion control practice factor (the ratio of soil loss with a certain
conservation practice to that of no practice)
On a long uniform slope, how does the erosion on the top half generally differ
from the bottom half? - CORRECT ANSWER-The top erosion is generally much
lower than the bottom
Soil loss equations are significantly less accurate for which type of events? -
CORRECT ANSWER-Specific weather events
Soil loss equations are most accurate at predicting the average soil loss over the
_________________? - CORRECT ANSWER-Long term
USLE formula can be used for estimating soil loss from what condition which
RUSLE cannot? - CORRECT ANSWER-disturbed forested conditions
The "R" factor is best found through obtaining it directly from ______? -
CORRECT ANSWER-maps
The erosion index developed by _________________ currently seems to provide
the most accurate "R" values - CORRECT ANSWER-Wischmeier
A map showing "R" values is called a ________________? - CORRECT
ANSWER-Isoerodent map
