ABSTRACT
This chapter provides a summary of routine instruments and experimental methods for the measurement of water depth, slopes, pressure, bed shear stress, drag forces and some fluid properties. It focuses on the determination of the water surface elevation as instrumentation and methods for bed level measurements. For hydraulics experiments, it is often adequate to use tables based on temperature and salinity to obtain necessary fluid properties. Mechanical systems such as lead lines, sounding poles, ordinary water gauges or rulers have been the earliest tools used for water depth measurements. The water surface slope and bed slope are gradients, and their determination requires the measurement of the vertical change of the water surface and bed level, respectively. Typical instruments for the measurement of fluctuating pressure contain either flexible membranes, capacitive sensors or piezotechnical elements. A Stanton gauge is a small apparatus that measures the pressure within the viscous sub-layer, restricting its application to hydraulically smooth flows.
