I have dug a shallow trench 5.4m long across the entrance of my drive which leads to a gravel private road. My intention is to build up something resembling a speed bump to prevent water running onto my plot.   Background:   Last winter I suffered repeated flooding episodes in my open foundation footings during heavy rain e.g. 1" overnight or 2" in a week. This autumn matters have improved because the uphill boundary of my plot now features a 40m long soil bund about 600mm hi