Hydraulic parameters of the block ramp with ridge type notch: the Grajcarek in Szczawnica, Polish Carpathians

Abstract

Aim of the study: The aim of this study is to analyze the hydrodynamic parameters in the area of one of the block ramp in the analyzed stream. Material and methods: The field research included geodetic measurements on the basis of which the longitudinal profile and cross-sections of the watercourse bed and structures were made. Numerical modelling of flood flows was also performed in the HEC-RAS program, from which hydrodynamic data were obtained. The data obtained from field measurements and numerical modelling were used to calculate the length of the energy dissipation basins of the structure and to determine the type of water movement using the Froude number. The calculations were performed for several variants. The real lengths of the energy dissipation basin were compared with the lengths of hydraulic jumps that are formed on them. Results and conclusions: The obtained results indicate that the length of the energy dissipation basin is too short because the hydraulic jumps go beyond them. As a result, a scour is formed below the structure, which in the event of further development may threaten the stability of the structure.

Keywords

• hydraulic parameters
• block ramp
• hydraulic jump
• ridge type notch
• energy dissipation basin