Ключевые слова: above, aquatic, aqueduct, assembled, canal, canalization, circle, civil engineering, confined space, corrugated, culvert, cylinder, down, drain, drainage, duct, gravel, hdpe, infrastructure, inside, inside of, installation, junction, main, manhole, outflow, perspective, pipe, pipeline, pipework, piping, plastic, polyethylene, polystyrene, pvc, rainwater, ribbed, rubber, sanitary, sewage, sewer, sewerage, system, trough, tube, tubing, utility, water, waterspout, waterway,