That would work but if you already have the traditional irrigation controller I would keep that as well. Use vera to enable or disable the timers output either by the rain sensor input as theal states or by switching the common line to the valves as I note earlier in the thread.
The rationale for this is some degree of failsafe. If for some reason Vera got locked up or the ZWave device didn't get the turn off the command, sprinklers could run for several hours/days. If the timer is still used the sprinklers will shut off if either vera shuts then off OR the tier shuts them off.
Sometimes in HA it isn't the general case you need to think about, rather the degenerative or failsafe case....
VeraLite (1), Leviton VRI10-1LX (8 ), VP00R-1LZ (5), VRS15-1LX (1), Intermatic CA3500 (10), CA5100 (1), Aeon Labs DSC26103 (5), Foscam FI8918W (2) , FI9821W V2 (1), DLINK DCS-932L (2), DCS-930L (1), GE45604 (2), GE45603 (5), Honeywell RTH8580WF (2), HA-09WD (1), Kwikset 910TRL ZW (1), Aeon MMote (2)