Eq. 20 has now been replaced by
QCe.i,j-eff (Ai,j-in.eff + D2)m+1 - QCe.i,j-eff
LUMe.i,j = ———————————————————
QRe.i,j-cell Dm+2 xi,jm (22.13)m
QCe.i,j-eff = [(QCe.i,j-cell D2) + (QCe.i,j-in Ai,j-in.)] / (Ai,j-in.eff + D2)
Ai,j-in.eff = Ai.j-in QCe.i,j-in / QCe.i,j-all
The original approach developed by Desmet and Govers (1996) for determining the L factor for grid cells applies where runoff is produced uniformly over the whole area contributing runoff to the cell so that the runoff coefficient for the cell (QCe.i,j-cell) equals that of the upslope area (QCe.i,j-in). When runoff is zero, the upslope area is effectively zero. In the context of determining the slope length factor for a cell, the approach given above considers the upslope area to vary depending on the ratio of the runoff ratio of the upslope area to that of the whole area (QCe.i,j-all). Details of the approach are subject to a paper to be published in the Soil Science Society of America Journal and the approach is used in the current software applying the USLE-M within AGNPS (AGNPS-UM) available from this WWW site.
firstname.lastname@example.org 3 Nov 2004.