New Hazard

Back to the Ashdown Forest where the event I am organising takes place in just 2 weeks. Today I was checking the route that the Juniors follow from the end of their courses back to Registration.  I was very alarmed to find a previous dry ditch had become a stream and waterfall.  Is it safe to let the juniors make their way back unaided over this hazard ?  The answer is no. I will have to  provide a rope over the stream and an adult with a walkie talkie ( in case they fall in)  to help them. Its too late now to change the courses that Mr P has planned over the summer when the ditch was dry.