New Approach for Evaluation of a Watershed Ecosystem Service for Avoiding Reservoir Sedimentation and Its Economic Value: A Case Study from Ertan Reservoir in Yalong River, China

Table 1

The model of calculating the quantity of sediment retention by vegetation in each cell followed by the flow path.

Cell ID	Sediment retention coefficient	Actual soil loss	The quantity of sediment retention by vegetation	The quantity of sediment that was passed to the next cell
	(no unit)	[t/(km^2·a)]	[t/(km^2·a)]	[t/(km^2·a)]
1	𝑅1	USLE1	0	USLE1
2	𝑅2	USLE2	USLE1×𝑅2	USLE1×(1−𝑅2)+USLE2
3	𝑅3	USLE3	[USLE1×(1−𝑅2)+USLE2]×𝑅3	[USLE1×(1−𝑅2)+USLE2]×(1−𝑅3)+USLE3
4	𝑅4	USLE4	{[USLE1×(1−𝑅2)+USLE2]× (1−𝑅3)+USLE3}×𝑅4	{[USLE1×(1−𝑅2)+USLE2]×(1−𝑅3)+USLE3}×(1−𝑅4)+USLE4

Note: it assumes that the first cell does not intercept the eroded soil which occurs by itself.