The last twenty-five years have seen great advances in the instrumentation available for hydrometry and in the procedures and methods for the measurement of discharge. Due to several reasons, this progress has not seen a parallel development of guidance material and standards.

At its Twelfth Session (Geneva, October 2004), the Commission for Hydrology of WMO, having reached a general consensus that information on the appropriate use of this instrumentation and methodologies is direly needed, identified under the priority thematic area "Basic systems (hydrometry and hydraulics)" an activity to develop a proposal and implement a project to assess the performance of flow measurement instruments and techniques against WMO standards.

A small expert team from the Open Panel of CHy Experts (OPACHE) on Basic Systems has developed a proposal, which suggests the implementation of a project with the main objective of making information on standardized test results on hydrometric instrumentation and measurement methodologies available to NHSs by providing a Web site as a forum for exchange of information among interested parties.

An exploratory meeting to further develop the proposal took place in Geneva from 25-27 April 2007. The final report and the PowerPoint presentations given during the meeting can be downloaded here:

As a consequence of the meeting, the original proposal has been reviewed. Please find here the revised " Proposal and Project Implementation Plan for the Assessment of the Performance of Flow Measurement Instruments and Techniques".