The latest NDMA figures suggest that the freeboard is down to about 4.3 feet (1.31 metres) as of 3 pm today. That is a reduction of about 70 cm on the day, meaning that we are probably less than two days from the point of overtopping:
I am reasonably confident of these values as the Focus geologists took this picture yesterday of the spillway:
The circled boulder is the crest of the spillway, so water flow will start when this point is reached. Of course the one potential problem is a slope failure on the spillway walls, which could block the channel. This is a real possibility, but we won't know until tomorrow.
Close up the channel at this point looks like this:
Unfortunately the large boulder will resist lateral cutting, initially at least, which is likely to increase the rate of down-cutting. This is unfortunate. Once the water reaches the top it will initially flow down this channel, crossing the summit of the dam:
And then will flow down here:
The disturbance here is from collapse of the banks induced by the seepage. Finally, it will flow down the main river channel: