The widely used low pressure culverts are operated in the drop range between 1.5 and 5.0 meters. They distinguish by the near critical pairing mode of bays: in the downstream the true hydraulic jump does not develop. In this case the undular hydraulic jump develops in the downstream. Article is devoted to the issues of the improvement of bottom paving structures in low pressure constructions and the technology of its erecting. Features of controlling the near-critical flows arising during the operation are analyzed. Possible ways of technology improvement of structures are given illustrated by the example of bottom paving structures with guide elements. Results of hydraulic researches validating this construction are given.