• Turbidity - the amount of sediment in suspension within the water.
• Salinity - The amount of substance (normally salt) dissolved in the water.
• Temperature - The temperature of the water sample.
• Pressure - Sum of water depth and barometric pressure.
All of the above parameters can vary considerably in any particular water
column but the assumption made with a single beam echo sounder is ....
• the sound travels near vertically so does not suffer any refraction.
• the sound travels there and back so is the average of all condition changes