# Stream Power Index

O.Conrad (c) 2003
Calculation of stream power index based on slope and specific catchment area (SCA).
SPI = SCA * tan(Slope)
References:
Moore, I.D., Grayson, R.B., Ladson, A.R. (1991):
'Digital terrain modelling: a review of hydrogical, geomorphological, and biological applications'
Hydrological Processes, Vol.5, No.1

## Parameters

Grid system
Grid system
  Grid system
Slope
Input Grid
Catchment Area
Input Grid
Stream Power Index
Output Grid
Area Conversion
Choice
  Available choices: no conversion (areas already given as specific catchment area), 1 / cell size (pseudo specific catchment area)