Perhaps 100-300 cumecs. Definitely mid 200s
The wave is on the grade 2/3 Aorere gorge section, but you can also park and play. Impeccable eddy service is provided by the groynes built for flood protection.
For park and play ask at Gareth Scott's place, on the corner of Cook Rd about 1km up Aorere Valley Rd from the Bainham store. Or phone 524-8968.
Turn off at the double farm gate on the left another 1/2 km up the valley, drive 200m down the cattle track to where it meets the river. Walk 200m upstream and you'll find a spot where you can see the wave and also easily duck under the electric fence.
The Aorere has huge floods, with a record high is 3500 cumecs. To catch the wave you usually need to be there within hours of a decent downpour, study the flow and rain graphs to figure out when.