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How is slope length calculated?
The slope length is calculated using the Pythagorean Theorem, where the vertical distance is the rise and the horizontal distance is the run: rise2 + run2 = slope length2. In this example, the facility would need more than 22 feet of tubing to cover the distance from the water sampler to the water source.
Which is the correct formula for LS?
Moore and Wilson (1992) presented a simplified equation using unit contributing area (UCA) to calculate LS for three-dimensional terrain:(6) LS = A s 22.13 m sin θ 0.0896 n , where As is the unit contributing area (m), θ is the slope in radians, and m (0.4–0.56) and n (1.2–1.3) are exponents.
How do you use Rusle equation?
RUSLE maintains the same empirically based equation as USLE to compute sheet and rill erosion as follows: A=RKLSCP where A is computed soil loss, R is the rainfall-runoff erosivity factor, K is a soil erodibility factor, L is the slope length factor, S is the slope steepness factor, C is a cover management factor, and …
How do you measure soil erosion?
To calculate the volume of soil eroded by water runoff in a specific area, measure the square area multiplied by the change in depth. For example, if the area in square meters is 20,000 and the lost soil height is 0.01 meters, then: Volume = 20,000 x 0.01 = 200 cubic meters.
What is slope length factor?
L is the slope length factor, representing the effect of slope length on erosion. It is the ratio of soil loss from the field slope length to that from a 72.6-foot (22.1-meter) length on the same soil type and gradient. Slope length values are generally too long when contour maps are used to choose slope length.
How to calculate slope length and slope steepness?
USLE/RUSLE contain parameters for slope length factor (L) and slope steepness factor (S), usually combined as LS. However a major limitation is the difficulty in extracting the LS factor. Methods to estimate LS based on geographic information systems have been developed in the last two decades.
How to calculate slope length factor in ArcGIS?
Calculation of Slope Length Factor LS Factor in ArcGIS. where A[r] is upslope contributing area per unit contour width, b [deg] is the slope, m and n are parameters, and a0 = 22.1m = 72.6ft is the length and b0 = 0.09 = 9% = 5.16deg is the slope of the standard USLE plot. The values of m (=0.6) and n (=1.3) were empirically derived.
How to calculate slope length using flow accumulation?
Flow accumulation, by default, gives you a value in pixels, so you need to multiply by the pixel size before you divide by 22.13 (coefficient of the RUSLE equation). The best method would consist in creating a weighting raster with the m value and use it when you compute the accumulation. Maybe you could try saga-gis software for creating LS.
How does the LS factor work in erosion?
LS factors = the slope length factor L computes the effect of slope length on erosion and the slope steepness factor S computes the effect of slope steepness on erosion. Values of both L and S equal 1 for the unit plot conditions of 72.6 ft. length and 9 percent steepness.