Fish passes allow a variety of species to travel upstream
Larinier fishpasses are often built at gauging structures to allow large migratory salmonids and coarse fish as well as a wide range of other species to travel upstream.
The introduction of fishpasses at gauging structures can affect the accuracy of flow gauging. To better understand the impact of the Larinier fishpass, and to inform the BS ISO 26906:2009 standard, Hydrometry - Fishpasses at flow measurement structures, we carried out an experimental research study to extend the existing information on the stage-discharge relationships. We completed a series of tests to investigate the discharge relationships for baffles 75, 100 and 150mm high.
We built 1:2 scale models in our general purpose flume. This facility is fitted with a volumatic tank which has a BSI calibrated level/volume relationship to an accuracy of ±0.02% and high accuracy micrometer gauges, providing the measurement quality needed for inclusion of study results in ISO and BSI Standards.
The test programme for each of the models included:
Our analysis led to recommendations for some limited revisions of the BS ISO 26906:2009 standard.
Our general purpose flume can also be used to model river structures and calibrate instrumentation.