design idea - Flooding

This week, the rain in blighty has reached near biblical proportions.  It's autumn and many roads have become flooded as fallen leaves have blocked drains causing several problems.  As a driver, you don't know where the edge of the road is and you also don't know where the drain is if you want to try an unblock it. I was wondering if I could come up with a design solution to solve these issues, so generated two ideas that are cheap to manufacture from plastic and polystyrene and are retrofittable to a current drain.

1. is a float that sits in the drain and as it starts to fill raises to indicate where the drain is. 

2. is an idea to stop the drain blocking by having a floating cage lift up to prevent leaves from clogging the top of the drain.   Both have issues, but are ideas in progress.