Back flow prevention

The channel across the drive collected the rain pouring down the slope in monsoon events, but the street surface water drain pipe is choked so it backs up and instead of discharging to the brook it flows back up our drain, up out of thes channel and threatens to flood our garage (which it has done several times). Local authority and Highways don’t care and one told me to claim on the house insurance if flooded. Just imagine the following year’s premium!
This will stop our garden being the flood path for 100 yards of road and adjoining fields.
Meanwhile I will report the blockage in the main drain every time it rains…..