This concrete "bridge" over the Borough Race served as an access to parts of the farm otherwise cut off by the construction of the water race, and also as an overbye, carrying rainwater on its deck over the race and not into it. The overbye and its vehicle (cart) track are in the bottom of a gully and effectively in a creek bed. Keeping storm water out of the race was essential to prevent contamination by run-off and to stop the water race from filling up too much and over-topping. Most overbyes were small and made from wood - there were probably hundreds of them. Just a few are big like this. I have found four or five, but there will be more on properties I haven't visited.