A cohesive strength meter (CSM) consists of a computer and water reservoir that is put under pressure by an external air cylinder. This water reservoir is connected to a sensor head that is inserted into the sediment. The CSM is designed to be able to deploy in situ and the sensor head can be submerged under water.
When testing the erodibility of sediments, a jet of water is fired by the CSM within the sensor head, placed near the sediment surface. This will cause a collapse of the sediment matrix at the sediment-water interface. Jet pressure is increased incrementally, and erosion is monitored based on sediment resuspension using an infrared transmission meter. A minimum of clay/silt is needed to ensure that erosion can be used as a synonym for ‘resuspension’. The initiation of erosion is typically identified by a 10 % drop in light transmission within the testing chamber.