The problem of transformation of quasimonochromatic wavetrains of surface gravity waves
with narrow spatial-temporal spectra on the bottom shelf is considered in the linear
approximation. By means of numerical modeling, the transmission and reflection
coefficients are determined as functions of the depth ratio and wave number (frequency) of
an incident wave. The approximation formulae are proposed for the coefficients of wave
transformation. The characteristic features of these formulae are analyzed. It is shown
that the numerical results agree quite satisfactorily with the proposed approximation
formulae.