Numerical Prediction for Reduction of Oxygen Deficient Water Mass by Ecological Model in Jinhae Bay

J. Ocean Eng. Technol. 2008;22(5):75-82.

Lee In-Cheol,Kong Hwa-Hun,Yoon Seok-Jin

Department of Ocean Engineering Pukyong National University,Samsung Heavy Industry Co. Ltd. offshore engineering team 1 piping design,Research Center for Ocean Industrial Development Pukyong National University

생태계모텔에 의한 진해만의 빈산소수괴 저감예측

이인철,공화훈,윤석진

부경대학교 해양공학과,삼성중공업 (주) 해양설계 ¹팀 배관설계,부경대학교 해양산업개발연구소

Keywords: Jinhae Bay, Oxygen deficient water mass (ODW), Numerical prediction, Sediment-water Ecological model(SWEM), ODW decreasing index ($ODW_{DI}$)

핵심용어: 진해만, 빈산소수괴, 수치예측, 수-저질 생태계모델, 빈산소수괴 체적감쇠 지수

Abstract

As a basic study for establishing a countermeasure for an oxygen deficient water mass (ODW), we investigated the variation of ODW volume according to the enforced total pollution load management in Jinhae Bay. This study estimated the inflowing pollutant loads into Jinhae Bay and predicted the reduction in ODW by using a sediment-water ecological model (SWEM). The result obtained in this study are summarized as follows: 1) The daily average pollutant loads of COD, SS, TN, TP, DIN, and DIP inflowing into Jinhae bay in 2005 were estimated to be about 12,218 kg-COD/day, 91,884 kg-SS/day, 5,292 kg-TN/day, 182 kg-TP/day, 4,236 kg-DIN/day, and 130 kg-DIP/day. 2) The calculated results of the tidal current by the hydrodynamic model showed good agreement with the observed currents. Also, an ecological model well reproduced the spatial distribution of the water quality in the bay. 3) This study defined the ODWDI (ODW decreasing index) in order to estimate the ODW decreasing volume caused by a reduction in the inflowing pollutant loads. As a result, the ODWDI was predicted to be about 0.91 (COD 30% reduction), 0.87 (COD 50% reduction), 0.79 (COD 70% reduction), 0.85 (ALL 30% reduction), 0.66 (ALL 50% reduction), and 0.45 (ALL 70% reduction). The ODW volume was decreased 1.5 $sim$ 2.6 times with a reduction in the COD, TN, and TP inflowing pollutant loads compared to a reduction in just the COD inflowing pollutant load. Therefore, it is necessary to enforce total pollution load management, not only for COD, but also fm TN and TP.