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Adjustment Factors for Unsteady State-Discharge Measurements

Author(s): N. Ozbey

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Keywords: Unsteady State-discharge; Hysteresis; And Adjustment Factor

Abstract: The effect of hysteresis or loop rating is most significant for mild sloped streams where backwater effects from downstream are not negligible and reaches downstream of locks or gates during periods of releases. SonTek Acoustic Doppler Velocity Meters were deployed at selected stream gauging sites with natural controls and irregular cross sections through Victoria. ADVM's flows were calibrated and verified with discharge measurements. Uncertainties in flows were estimated utilising the method articulated in the International Standard, ISO 15769. Steady flow rating curves were derived from loop. Adjustment factor, 1/vwS c and, Sc0.5/n (the term as an integrated parameter in Manning's Equation) of discharges recorded during the events were calculated. Relationships between these terms were sought for the sites with different hydraulic characteristics. The term of Manning Equation, as a single parameter, were calculated for two sections in close proximity. Results indicate that unsteady state-discharge measurements at a gauging site can be calibrated with a family of curves by evaluating 1/vwS c as a single parameter utilising the Jones Formula based on kinematic wave assumption.

DOI:

Year: 2011

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