This Technical Report provides a synopsis of the methods of flow gauging that can be deployed in closed
conduits flowing part full, i.e. with a free open water surface. It provides a brief description of each method
with particular reference to other International Standards where appropriate, the attributes and limitations of
each technique, possible levels of uncertainty in the flow determinations and specific equipment requirements.
The uncertainties quoted herein are expanded uncertainties with a coverage factor of 2 and an approximate
confidence level of 95 %.