.\" %W% %G%
.TH river 1
.SH NAME
river \- generate drainage accumulation map layer
.br
.I (GRASS-GRID Tool)
.SH SYNOPSIS
.nf
river
.fi
.SH DESCRIPTION
River
generates a drainage accumulation map layer from elevation
data. Input is interactive.  Also generated are an adjusted
drainage direction map (adjusted to allow for the draining
of water across lakes), and an optional product which denotes
designated lakes, pits, and redirected routes. User supplies
the elevation filename used for input (this should contain
true elevation values, but may be filtered data if desired),
all output map names, and the desired watershed outlet point.
An implied watershed boundary is generated.  Subbasin boundaries
are not supplied as part of this routine.  The resulting
drainage accumulation file can be used by the GRASS routine "thin"
to generate a stream network within the designated watershed.
River needs as input a list of pit points, sorted in decreasing 
order according to elevation value.  This list can be generated
using the pits program.
.SH NOTES
river works properly with supercell layers.
The current window setting is used.  The user should
take care that the desired watershed is within the current
window.

.SH SEE ALSO
pits[1]

.SH "AUTHOR"
Marjorie Larson, U.S. Army Construction Engineering Research Laboratory
.br
Larry Band, Dept. of Geography, University of Toronto
