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CPESC Erosion Prediction (RUSLE and MUSLE)
the amount of eroded soil that is delivered to a point in the
What is sediment yield
watershed that is remote from the origin of the detached
soil particles
Sediment yield does not include the sediment that is deposited after it is eroded but before it
_______________? reaches the point of interest in the watershed.
Do RUSLE and USLE NO
estimate sediment yield?
What does RUSLE stand for? Revised Universal Soil Loss Equation
What do both the RUSLE the annual erosion expected on field slopes
and USLE compute?
What is the RUSLE equation? A=RxKxLxSxCxP
spatial average soil loss and a temporal average soil loss per
What does the "A" stand for
unit of area. Expressed in the units selected for K and the
in the RUSLE formula?
period selected for R. (generally expressed as tons per acre
per year)
What does the "R" stand for rainfall-runoff erosivity factor (rainfall index plus a factor for
in the RUSLE formula? any significant runoff from snow melt)
What does the "K" stand for in soil erodibility factor (the soil loss rate per erosion index unit for a
the RUSLE formula? specified soil)
What does the "L" stand for in slope length factor (ratio of soil loss from the field slope
the RUSLE formula? length compared to a standard length of 72.6 ft under
identical conditions)
What does the "S" stand for in slope steepness factor (the ratio of soil loss from the field
the RUSLE formula? slope compared to a 9% slope under identical conditions)
What does the "C" stand for in cover management factor (the ratio of soil loss from an area
the RUSLE formula? with specified cover and management to soil loss from an
identical area in bare condition)
What does the "P" stand for in erosion control practice factor (the ratio of soil loss with a
the RUSLE formula? certain conservation practice to that of no practice)
, On a long uniform slope, how The top erosion is generally much lower than the bottom
does the erosion on the top half
generally differ from the
bottom half?
Soil loss equations are Specific weather events
significantly less accurate for
which type of events?
Soil loss equations are most Long term
accurate at predicting the
average soil loss over the
_________________?
USLE formula can be used disturbed forested conditions
for estimating soil loss from
what condition which RUSLE
cannot?
The "R" factor is best maps
found through obtaining
it directly from_____?
The erosion index developed by Wischmeier
_________currently seems to
provide the
most accurate "R" values
A map showing "R" values is Isoerodent map
called a
________________?
The soil erodibility factor "K" The ease with which soil is detached by splash during rainfall
value can be easily thought or by surface flow, or both.
of as____________?
The "K" factor can be found A soil erodibility factor table for the area you are in. If not
using what method? available then it can be calculated using a Soil Erodibility
Nomograph.
Which soil layers are generally The B and C layers since they are generally exposed after stripping.
used for the "K" value on
construction sites?
Erosion increases as slope length increases
____________________________?
Slope length is defined as The slope gradient decreases enough that
the horizontal distance deposition begins runoff becomes
between the origin of concentrated in a defined channel
overland flow to the
point where either
_____________?
Slope runoff will usually 400ft however 1000ft can occur on occasion
CPESC Erosion Prediction (RUSLE and MUSLE)
the amount of eroded soil that is delivered to a point in the
What is sediment yield
watershed that is remote from the origin of the detached
soil particles
Sediment yield does not include the sediment that is deposited after it is eroded but before it
_______________? reaches the point of interest in the watershed.
Do RUSLE and USLE NO
estimate sediment yield?
What does RUSLE stand for? Revised Universal Soil Loss Equation
What do both the RUSLE the annual erosion expected on field slopes
and USLE compute?
What is the RUSLE equation? A=RxKxLxSxCxP
spatial average soil loss and a temporal average soil loss per
What does the "A" stand for
unit of area. Expressed in the units selected for K and the
in the RUSLE formula?
period selected for R. (generally expressed as tons per acre
per year)
What does the "R" stand for rainfall-runoff erosivity factor (rainfall index plus a factor for
in the RUSLE formula? any significant runoff from snow melt)
What does the "K" stand for in soil erodibility factor (the soil loss rate per erosion index unit for a
the RUSLE formula? specified soil)
What does the "L" stand for in slope length factor (ratio of soil loss from the field slope
the RUSLE formula? length compared to a standard length of 72.6 ft under
identical conditions)
What does the "S" stand for in slope steepness factor (the ratio of soil loss from the field
the RUSLE formula? slope compared to a 9% slope under identical conditions)
What does the "C" stand for in cover management factor (the ratio of soil loss from an area
the RUSLE formula? with specified cover and management to soil loss from an
identical area in bare condition)
What does the "P" stand for in erosion control practice factor (the ratio of soil loss with a
the RUSLE formula? certain conservation practice to that of no practice)
, On a long uniform slope, how The top erosion is generally much lower than the bottom
does the erosion on the top half
generally differ from the
bottom half?
Soil loss equations are Specific weather events
significantly less accurate for
which type of events?
Soil loss equations are most Long term
accurate at predicting the
average soil loss over the
_________________?
USLE formula can be used disturbed forested conditions
for estimating soil loss from
what condition which RUSLE
cannot?
The "R" factor is best maps
found through obtaining
it directly from_____?
The erosion index developed by Wischmeier
_________currently seems to
provide the
most accurate "R" values
A map showing "R" values is Isoerodent map
called a
________________?
The soil erodibility factor "K" The ease with which soil is detached by splash during rainfall
value can be easily thought or by surface flow, or both.
of as____________?
The "K" factor can be found A soil erodibility factor table for the area you are in. If not
using what method? available then it can be calculated using a Soil Erodibility
Nomograph.
Which soil layers are generally The B and C layers since they are generally exposed after stripping.
used for the "K" value on
construction sites?
Erosion increases as slope length increases
____________________________?
Slope length is defined as The slope gradient decreases enough that
the horizontal distance deposition begins runoff becomes
between the origin of concentrated in a defined channel
overland flow to the
point where either
_____________?
Slope runoff will usually 400ft however 1000ft can occur on occasion
