The three segments of this chapter introduce phenomena that are of specific interest in the area of hydraulics. Where applicable (Cavitation, Sect. 15.1 and Sediment Transport, Sect. 15.3) introductory and descriptive material regarding the topic is provided. Terminology, physical examples and motivating descriptions introduce the comprehensive Cavitation subsection. Examples of the types of flows in which cavitation occurs are provided. This information sets the stage for a description of the types of facilities and instrumentation that are necessary to study the problem. Numerous photographs and descriptive sketches clarify and complement the text. The wave height measurement segment first deals with fixed position single "point" techniques. More advanced techniques for: i) wave surface shape along a horizontal line, and ii) two-dimensional surface geometry measurements for laboratory and field observations are then described. Following the introduction to sediment transport phenomena and terminology, the methods of measurement: manual, optical and acoustic are given detailed descriptions including calibration techniques for the latter two methods. Bed load sediment measurements: pressure difference, sediment trapping and acoustic are next described. Total load and the less common measurement techniques, plus references complete the subsection.