Usually these safety gates have been open. But in case of a dam failure they were closed automatically by the resulting current, because they are installed at an angle at narrowed places. The photograph shows gates near Unterölsbach. Such gates are installed at regular intervals in longer pounds (i.e. sections without locks) and at both sides of dams. They minimize the escape of water in case of dam failures and they give the possibility of dewatering canal sections for repair work.