Water waves, one of the common natural phenomena, are recognized as complex
and often turbulent. A generalized (2+1)-dimensional Korteweg-de Vries system for
the shallow-water waves is conducted in this paper. We perform the Painlev´e analysis
and find that the system is Painlev´e integrable. We study the inelastic interactions of
the lumps for the system. We find that two lumps, which propagate along the curves
with the equal amplitude, are symmetric about the x axis before the interaction, where
x is a scaled spatial variable. After the interaction, amplitudes of the two lumps are
different, but in the process of moving, the lower lump gradually increases, while the
higher lump gradually decreases, and the velocities of two lumps at the infinity are
equal. We observe two different inelastic interactions of the three lumps: (1) the
three lumps are symmetric in time and space, and they slowly contract (before the
interaction) and swell (after the interaction); (2) the three lumps slowly fuse and after
the interaction they form a straight line forward, and their amplitudes are gradually
equal when t → ∞.