How is water depth commonly determined in modern hydrographic surveying?

In modern hydrographic surveying, water depth is primarily determined using acoustic soundings, also known as sonar technology. This method involves emitting sound waves from a transducer, which travels through the water and reflects off the seabed. By measuring the time it takes for the sound waves to return to the transducer, surveyors can calculate the depth of the water. This technique allows for highly accurate and efficient mapping of underwater topography, making it the standard practice in the field.

Acoustic soundings are advantageous because they can cover large areas quickly and can operate in various water conditions, including murky or deep waters where visual inspections or buoy measurements are impractical. While alternative methods like satellite data can provide information about large areas, they lack the necessary resolution and accuracy for detailed depth measurements required in hydrographic surveys.