A proper understanding of sediment transport is extremely important in many areas of engineering and socio-economic development. On time scales of months to years, the knowledge of where sediment accumulates could save billions of dollars on annual port dredging and beach nourishment. On length scales of deltas, estuaries and coastal zones, such knowledge plays a crucial role for decision-makers to govern the development of a country or region. Unfortunately, high-fidelity, long-term in situ data of sediment transport, particularly suspended particulate matter concentration are often unavailable and/or unreliable. Hence, this project aims to propose a novel approach to reduce the calibration effort and improve the accuracy of long-term, high-frequency in situ measurements. This project will integrate field and laboratory studies to demonstrate that combination of at least one pair of optical and acoustic (O/A) sensors will help to “see” the mud better and “hear” the sand better, which in turn allows us to comprehensively reproduce detailed information of suspended sediment concentration profile in a river, estuarine or coastal zone. Field measurements help to provide input of the boundary conditions for the experiments, whereas the experiments help to isolate variables in order to decipher the behavior of O/A signals that occur in nature. This project will 1) enhance understanding of O/A signals behaviors under similar and different environments, 2) derive empirical functions from field and lab data to describe the ratio of O/A signals as a dependent variable of environmental characteristics and 3) test the functionality and efficiency of the empirical functions, obtained above, with field data collected from different parts of Europe. The primary intellectual merit of this project will be a guideline for water agencies and local authorities throughout Europe and the world to improve their performance in long-term, high-frequency monitoring of water quality.