I don't think even in days of old, lengthsmen could have prevented this or even have the staff on the ground. That particular day was horrific with the volume of water falling from the sky and I would imagine that all CRT ground staff were running in all directions.
With regard to the shroppie, such was the volume of water that the lock paddles on Hurleston were opened to stop the reservoir from overflowing, the temporray dam at Bridge 80 was removed to allow the massive flow from Audlem to come through, River Weaver was about to top the banks and a large number of CRT staff were involved in that especially to try and protect the towns and villages alongside.
The use of overflows and side paddles to regulate the flow also have to be consistent with not flooding other area's. It was a pretty intense day with the weather.