Well,
it was not necessary to move stuff under $GISBASE/source/Incoming/R.water.
However after all this you need to run Makelinks for r.water.fea to be
correctly installed. Makelinks must be run under $GISBASE/src/CMD.
Next to run r.water.fea just type r.water.fea on the GRASS prompt. The
programs in $GISBASE/etc are sub programs that r.water.fea needs and
they are not intended to be run manually.
Hope this helps
Nalneesh Gaur