Turbidity and Dredging by IADC

The International Association of Dredging Contractors (IADC) has just released its latest ‘Facts About’ publication, named ‘Turbidity and Dredging’.

‘Facts About’ is a series of concise easy-to-read leaflets which give an effective overview of essential facts about specific dredging and maritime construction subjects.

Each leaflet provides a kind of ‘management summary’ for stakeholders who need a quick understanding of a particular issue.

These leaflets are part of IADC’s on-going effort to support clients, consultants and others in understanding the fundamental principles of dredging and maritime construction because providing effective information to all involved parties is an essential element in achieving a successful dredging project.

Turbidity and Dredging

Turbidity is an optical quality of water and describes how clear or transparent the water is. It describes the degree to which water contains particles that cause cloudiness or muddiness resulting in the disturbance of sunlight. Water is turbid – that is cloudy, opaque or thick – when it contains suspended silt.


If turbidity is low, sunlight shines through the water in a straight line down to the waterbed. When turbidity increases it changes the direction of the light, so that the light scatters, illuminating the particles in the water, much the way a ray of sunlight illuminates specks of dust in the air.

The cloudier the water, the greater the turbidity. The further sunlight penetrates the water, the higher the water clarity and the lower the turbidity. Turbidity is a natural phenomenon that occurs in bodies of water, be it oceans, lakes or rivers.

Turbidity is not itself a pollutant, but indicates how much sediment and organic matter are in the water. High turbidity may be caused by a high content of fine sediments or organic particles.

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