I don't understand how this would work... is there some surefire way of knowing it is raining, and then somehow opening up the storm drains in time for the runo

I don't understand how this would work... is there some surefire way of knowing it is raining, and then somehow opening up the storm drains in time for the runoff? Remember that if this automatic opening-closing mechanism fails, you get widespread flooding, likely leading to a lot of property damage and maybe even some lives lost depending on the severity of the storm.