36. Every person constructing or improving a bridge to cross a watercourse or a fish habitat shall ensure, at the time of the work, that diversion structures, such as channels, dikes and caissons, do not obstruct the passage of fish or reduce the width of the watercourse by more than 2/3, as measured from the natural high-water mark. At the end of the work, he shall remove the dikes and fill in any channels that were used to divert the watercourse and are no longer in use.