Phosphorus and nitrogen cyclings in the pelagic system of hiroshima bay: Results of numerical model simulation

Kittiwanich, Jutarat; Yamamoto, Tamiji; Hashimoto, Tsuyoshi; Tsuji, Kazuhiko; Kawaguchi, Osamu

doi:10.1007/s10872-006-0071-5

Cited by 8 publications

(2 citation statements)

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“…It is noted that the upper limit of the tidal compartment of the delta is 13 km upstream from the mouth of the Ohta‐Floodway branch, and the maximum salt intrusion length is about 11 km (Kawanisi, Razaz, Kaneko, & Watanabe, ). According to the records at the Yaguchi station for the period from 1987 to 1997, the monthly river discharge was highly variable within the range 9–380 m 3 s −1 with a mean value of 80 m 3 s −1 , which is about 12 times smaller than the monthly averaged water exchange volume at the estuary mouth (Kittiwanich et al, ). The freshwater inflow into the Ohta‐Floodway and Ohta branches is controlled by the Gion and Oshiba floodgates, which are located near the bifurcation junction.…”

Section: Geographic Settings and Discharge Measurementsmentioning

confidence: 99%

“…It is estimated that the area contributes about 72% of the total annual oyster production in Japan (AAFFS, 2001). Acquisition of the freshwater discharge over the delta's branches has become a high-priority issue for local water resource management because there has been an increase in the ecosystem vulnerability due to changes in environmental flows (Kittiwanich, Yamamoto, Hashimoto, Tsuji, & Kawaguchi, 2006;Yamamoto, 2003).…”

Section: The Hiroshima Delta In Japanmentioning

confidence: 99%

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A simple approach to estimating freshwater discharge in branched estuarine systems

Nguyen

Nguyễn²

2018

Hydrological Processes

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In tidal estuaries, quantifying freshwater discharge is still a difficult problem that has not yet been overcome due to the inherent difficulty in measuring and analysing the tidal discharge, especially during periods of low river flow. Because observations are often made in the stations further upstream, where the ratio of river to tidal discharge is large, it remains difficult to determine the discharge rate in the saline region. Freshwater discharge estimation is even more difficult in a branched estuary system having multiple diversion channels that connect with each other at a junction. To date, several methods have been developed for estimating freshwater discharge in estuaries. The most widely used are analytical and conceptual models that employ salinity as the principal trace and numerical simulations. However, these methods are very time consuming and costly as they require large sets of observations before the computations can take place. This paper presents a simple approach to investigating the discharge distribution over branched channels by considering the energy loss due to friction. We develop an analytical model that can obtain the discharge rate quantitatively at a junction where the main flow bifurcates into two branches. The model uses the bed roughness, tidal water level, and cross‐sectional profile under tidally averaged conditions as input data. Two selected estuarine systems in the Hiroshima delta in Japan and the Mekong delta in Vietnam have been investigated. Computations of the newly developed model show good agreement with earlier published results computed by sophisticated analytical and numerical models.

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Section: Geographic Settings and Discharge Measurementsmentioning

confidence: 99%

Section: The Hiroshima Delta In Japanmentioning

confidence: 99%