This paper reports on the study of copper-nickel alloy (Cu70-Ni30) surface modifications during the corrosion-erosion process taking place in flowing water containing marble particles. The surface modifications were evaluated at room temperature under agitation by potentiodynamic polarization curves and Electrochemical Impedance Spectroscopy (EIS). The electrochemical measurements showed that the corrosion current density decrease from 6,3mA/cm2to 4,8 mA/cm2 whenthe marble powder concentration increases from 0 to 8 ppm. The morphology and the nature of corrosion products, formed on the copper alloy surface, were studied by optical microscopy and micro-Raman spectroscopy. At low concentration (from 0 to 4 ppm) the structural analysis showed the presence of Cu2O and CuO compounds while at 8 ppm the passive films are formed of Cu2O and NiO. White deposits of CaCO3 and a local abrasion are also evidenced for 8 ppm. The mechanism of Cu70-Ni30 corrosion-erosion as function of marble powder concentration are discussed. At low concentration (2 and 4 ppm) the presence of marble solid particles in flowing water leads to erosion and corrosion of the surface and for 8 ppm both erosion and abrasion are clearly observed.