1. General Requirements

Selecting the proper water measurement device for a particular site or situation is not an easy task. Many site-specific factors and variables must be considered and weighed. In addition, each system has unique operational requirements and concerns. Reliable estimates on future demands of the proposed system and knowledge of the immediate measurement needs are beneficial. Government laws and compact agreements should be checked for possible selection constraints before selecting a measurement device. Contractual agreements for the purchase of pumps, turbines, and water measuring devices for districts often dictate the measurement system required for compliance prior to payment. These constraints may be in terms of accuracy, specific comparison devices, and procedures. Bos (1989) provides a more detailed discussion on the selection of open channel water measurement devices than the information included here. He also provides a selection flow chart and a table of water measurement device properties to guide the selection process. In this chapter, we discuss selection issues for the most common devices used in the United States.