Abstract: The present invention describes a low-cost, portable multi-parameter, turbidity sensor based on optical fiber. The sensor quantifies the transmission and scattering of radiation (nephelometry) in a fluid through radiation emission in two or more wavelengths. Inc invention can be used to estimate concentration of suspended sediments, to distinguish the type of sediment based on color, to distinguish different particle-size classes, and to identify and determine the concentrations of different suspended-sediment fractions. The sensor comprises the following elements: radiation emitter of two or more wavelengths (2), a radiation receiver to measure the transmitted radiation. (2), a radiation receiver to measure the scattered radiation (3), and an inner space (4) of the measurement unit containing the fluid being evaluated.