Pipeline watercourse is a pipeline laid for gases and fluids transmission laid via water courses (rivers, lakes, water storages, sea areas, etc.). There are river, sea and swamp crossings classified according to the type of a water body. There are water, oil, oil products and gases crossings classified according to the type of transported product; single and double pipe crossings – according to the crossing design.

In addition, pipeline subway crossings are distinguished by the immersion depth, internal pressure and diameter, crossing technique, number of parallel pipes laid, as well as by the transported product environmental impact. If the pipeline crossing mass is not enough for its submersion, cast-iron and concrete weights are used. To avoid the transfer of the transported toxic product into the water body, double pipe (pipe in pipe) crossings are used.