Long-term measurement of stream flow and salinity in a tidal river by the use of the fluvial acoustic tomography system

Kawanisi, Kiyosi; Razaz, Mahdi; Kaneko, Arata; Watanabe, Satoshi

doi:10.1016/j.jhydrol.2009.10.024

Cited by 61 publications

(30 citation statements)

References 5 publications

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“…The westernmost branch is calledŌta Diversion Channel. Long-term studies of the river discharge by Kawanisi et al [19] with fluvial acoustic tomography system (FATS) indicated that during normal days the channel receives up to 15% of theŌta River discharge; hence, most often there is a moderate estuarine circulation in the channel. At the survey site tidal currents generate peak velocities of 0.65 m s −1 and −0.5 m s −1 respectively during ebb and flood with a maximal tidal range of 4 m in a spring tide.…”

Section: Study Area and Methodsmentioning

confidence: 99%

Turbulence characteristics in the bottom layer of a shallow tidal channel

Razaz

Kawanisi

2012

Journal of Turbulence

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Observation of a shallow tidal channel was executed to examine turbulent evolution in ideal condition of weak, stratified flow for a complete cycle of semi-diurnal tide. Duration of this study allows a maximum velocity variation and therefore gives comprehensive interpretation of the relevant processes such as momentum and heat transfer, turbulent kinetic energy (TKE) production and dissipation rates. Under weak stratification condition dominant through the observation period testing the parameterization of dissipation rate in the Mellor-Yamada type models revealed that close to the bed perhaps due to boundary effects experimental dissipation closure constant values were remarkably larger than commonly used value of 16.6. Also, the effect of extending critical Richardson number Ri cr to infinity on parameterization of stability functions, eddy viscosity, and turbulent Prandtl number in Kantha-Carniel model was also examined. It was found that despite Kantha-Carniel model reconstructed bottom boundary layer (BBL) turbulence characteristics well during the flooding tide, it underestimates those parameters during the ebbing tide partially due to underestimation of turbulence macroscale.

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Section: Study Area and Methodsmentioning

confidence: 99%

Turbulence characteristics in the bottom layer of a shallow tidal channel

Razaz

Kawanisi

2012

Journal of Turbulence

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“…However, the methodology is limited to fully alluvial, undisturbed systems (i.e., with limited flow regulations and dredging) with semidiurnal tides, and excludes tidal inlets, bays, rias, fjords, sounds, and submerged river valleys. Several recent studies have introduced methods to calculate discharge in tidal rivers far from the mouth [ Hoitink et al ., ; Sassi et al ., ; Kawanisi et al ., ; Chen et al ., ]. However, these methods cannot capture downstream losses due to infiltration, evaporation, and water diversion, or gains due to small tributaries, groundwater recharge, and storm water/sewer outfalls.…”

Section: Introductionmentioning

confidence: 99%

Estimating river discharge using multiple‐tide gauges distributed along a channel

2016

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Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal intrusion reach, such that inputs and losses occurring closer to the ocean are not included. Here, we develop a method of estimating river discharge using multiple gauges and time‐dependent tidal statistics determined via wavelet analysis. The Multiple‐gauge Tidal Discharge Estimate (MTDE) method is developed using data from the Columbia River and Fraser River estuaries and calibrated against river discharge. Next, we evaluate the general applicability of MTDE by testing an idealized two‐dimensional numerical model, with a convergent cross‐sectional profile, for eighty‐one cases in which nondimensional numbers for friction, river flow, and convergence length scale are varied. The simulations suggest that MTDE is applicable to a variety of tidal systems. Model results and data analyses together suggest that MTDE works best with at least three gauges: a reference station near the river mouth, and two upstream gauges that respond strongly to distinct portions of the observed range of flow. The balance between tidal damping and amplifying factors determines the favorable location of the gauges. Compared to previous studies, the MTDE method improves the time resolution of estimates (from 2.5 to <1 week) and is applicable to systems with mixed diurnal/semidiurnal tides. However, model results suggest that tide‐induced residual flows such as the Stokes drift may still affect the accuracy of MTDE at seaward locations during periods of low river discharge.

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“…However, in FATS the cross-sectional averaged velocity along the transmission line is calculated using the multi-ray paths which cover throughout the cross-section. Based on the measuring principles of FATS the cross-sectional average velocities in the direction of stream flow are estimated by the following formula 5) :…”

Section: Materials and Methods (1) Utilization Of The Fatsmentioning

confidence: 99%

“…The Gion Floodgate which is located in the diversion channel consists of three movable sluice gates, of which usually only one sluice gate is opened. The inflow discharge at this branch is about 10-20% of the total flow rate of the Ota River on normal days 5) . This difference in the water discharge variations causes different salt intrusion mechanisms at the Ota main branches.…”

Section: Introductionmentioning

confidence: 96%

Investigation of Salt Intrusion Variability Using Acoustic Tomography System

Soltaniasl

Kawanisi

Razaz

2013

J. JSCE

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In the present study, the variations of the salinity and water discharge in the main branches of the Ota Estuary were investigated using the Fluvial Acoustic Tomography System (FATS). The Ota Estuary has a branched section of the Gion and Oshiba. The response of the salinity variations at the branches can be described as a power-law of river discharge. The exponents -0.53 and -3.86 at the Gion and Oshiba implied significant differences in the salt intrusion variations in these branches. The mechanisms of the salt intrusion at the site study were analyzed using the salt decomposition method based on the FATS data. The results indicated that the advection is the dominated seaward mechanisms at the both branches. However, the variations in the landward directed mechanisms were influenced by the triple correlation between the salinity, water velocity and water level fluctuations.

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Long-term measurement of stream flow and salinity in a tidal river by the use of the fluvial acoustic tomography system

Cited by 61 publications

References 5 publications

Turbulence characteristics in the bottom layer of a shallow tidal channel

Turbulence characteristics in the bottom layer of a shallow tidal channel

Estimating river discharge using multiple‐tide gauges distributed along a channel

Investigation of Salt Intrusion Variability Using Acoustic Tomography System

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