After completion of sounding procedure, next step involved is figuring gauge readings. Gauge reading is taken because of continuous change in level of water, which might affect result of survey.

Sounding involves in measuring depth of water below water surface, which requires certain equipments like, sounding boat, lead lines, fathometer, sounding machine, sounding pole.

Electro-magnetic gauge involves determination of discharge measurement of a stream. For obtaining result, a current meter is used which can establish a stream gauge.

Rating curve established by discrete measurements of stream flow by velocimeter, which can be used at stage measurements to determine volumetric stream flow discharge.

The least count of instrument can be given as
K = v / A. on substitution, we get
K = 50 / 21 = 2.38 m.

All water level gauges are capable of measuring water depth but, ultrasonic device is capable of determining water in a stilling well or directly in a canal.

In case of small scale surveys, triangulation will be more than required and usage of tape is preferred over it. This can have an advantage in economic perspective and also in terms of obtaining result.

Acoustic rain gauge is also referred as a hydrophone, is able to sense sound signature from each drip of rainfall that strikes surface. It is possible to invert underground sound field to estimate drop size distribution.

The velocity of sound in sea water can be determined by using formula,
V = 1410 + 4.21*T ? 0.037* T² + 1.14*S. on substitution, we get
V = 1410 + 4.21*32 ? 0.037*32² + 1.14*2.43
V = 1509.6 m/s.

Yacht survey or boat survey is simply detailed inspection of boat, which must be done by an experienced surveyor. The vessels used in case of boat are surveyed for having a better scope.