A consequence of stirring sea bottoms within construction sites is that suspended particles are being released. Pollutants such as heavy metals are often bonded to suspended particles which can spread over long distances. Analyzing the levels of particles in the water can either be made in a laboratory, or by measuring turbidity. Turbidity is a measure of the water’s ability to diffuse light and is used to determine the content of suspended material. This thesis is made in collaboration with AFRY who is preforming water sampling during a construction of a new quay area in Kallholmsfjärden, Skellefteå. The purpose of this study has been to investigate if, and how, suspended substances are being spread during water-based constructions that causes stirring of the sea bottom. The study was carried out by analyzing data sampled from Kallholmsfjärden. In summary, the result indicate that water-based constructions may result in suspended substances being spread into the water. Suspended material is correlating with turbidity, which means that turbidity can be used as an indicator for suspended materials. The kind of operation preformed during construction, affects the turbidity and dredging leads to higher particle scattering than padding. The result underlines the importance of taking preventive measures that reduce particle scattering, and one way of doing that is by using silt curtains. According to the result, silt curtains fulfill its purpose by preventing particle scattering. Finally, there is no difference in suspended material between dissimilar depths. The result of this theses is relevant when planning similar projects.