전차륜느 연안역에서 큰 스케일에서의 물질수송에 대한 관점에서 보면 조류보다 더 중요한 역할을 한다. 이러한 잔차류의 주된 성분은 조석 잔차류이며, 취송류, 밀도류 등도 이 흐름을 변동시키는 중요한 인자들이다. 이러한 연안역의 흐름의 특성을 규명하기 위해서는 3차원 유동모델의 적용이 필수적이다. 본 연구는 하천으로부터 담수유입에 의한 연안수역의 성층화 구조를 다루는데 초점을 두었으며, 이를 위해 3차원 밀도류모델을 적용하여 울산만의 유동을 재현하고, 담수유입에 의한 성층화 구조를 규명하였다. 그 결과 울산만과 같이 담수유입이 존재하는 반폐쇄 하구에서는 표층에서는 만외로 유출하고, 저층에서는 만내로 유입하는 흐름이 발생하였다. 또한 만내방향으로의 바람이 존재하는 경우에는 표층에서는 만내로 유입하는 흐름이, 저층에서는 이에 대한 보상류로 만외로 유출하는 흐름이 발생하는 것을 알 수 있었다. 이러한 해수유동결과는 해양목장 조성을 위한 인공어초투하, 연안표사 제어를 위한 잠제건설, 해저산맥 조성 등으로 인한 연직방향으로의 용승현상에 대한 규명이나 심층수 활용을 위한 기초연구에 적용이 가능할 것으로 사료된다.

This study was to evaluate the impact of river runoff and salt intrusion by tide on nutrient balance of estuary during a complete tidal cycle. 24 hours time series survey was carried out during a spring tide July 2001 on a tidal estuary in the Keum river. Three stations(A,B,C) were set along a transect line of about 10km, which linked the lower part of estuary dyke to the subtidal zone. Surface water was sampled simultaneously at each station every hours for the determination of nutrients. Water temperature, pH and dissolved oxygen were measured in situ. Riverine input of silicate and nitrate during ebb tide significantly increased the concentration of all stations. Conversely, during high tide, nutrient concentration were lowered by the mixing of fresh water with sea water. Ammonium nitrogen concentration were higher at intertidal zone(Stn.B) due to sewage inflow to Kyeongpo stream and ammonium release under anaerobic conditions. Also, these results was discussed as a biological component that influences the processes of nutrient regeneration within the estuary. Best correlations were found at lower part of estuary dyke(Stn.A) for salinity against DIN(Y=0.121 Sal.+4.97, r2=0.956) and silicate(Y=0.040 Sal.+2.62, r2=0.785). But no significant correlation was found between salinity and ammonium. Unbalanced elemental ratio(N/P, Si/N and Si/P) depended significantly on the import of nutrients (silicate & nitrate nitrogen) from river and stream. The effect of the tidal cycle and river runoff is important that in determining the extend of the variations in nutrient concentrations at all station.

Estimation of current and future loading from watershed is necessary for the sound management of water quality of an estuary lake. Pollution sources of point and non-point source pollution were surveyed and Identified for the Koheung watershed. Unit factor method was used to estimate potential pollutant load from the watershed of current conditions. Flow rate and water qualify of base flow and storm-runoff were monitored in the main streams of the watershed. Estimation of runoff pollutant loading from the watershed into the lake in current conditions was conducted by GWLF model after calibration using observed data. Prospective pollutant loading from the reclaimed paddy fields under cultivation conditions was estimated using the modified CREAMS model. As a result, changes of pollutant loading into estuary lake according to non-cultivation and cultivation conditions of reclaimed tidal land were estimated.

낙동강 하구수에서의 변이원성 물질에 의한 오염 상황을 파악하기 위하여 1998년에 각 계절별로 1회씩 총 4회에 걸쳐 낙동강 하구 10개 지점에서 blue rayon법을 이용한 Ames test를 실시하여, 3환 이상의 다환화합물에의한 변이원성을 조사하였다. 이 중 5월에 공업지역 부근인 제 1지점(하단동 부근)과 제 4지점(장림동 부근)에서 채취된 시료에서 현저한 변이원성이 관찰되었는데, 제 1지점의 시료에서는 S9 mix존재 및 비존재 하의 TA98, TA100 세포주 모두 현저한 용량 의존적 양성반응을 나타내어, 이 지점은 frame shift형의 직접 및 간접돌연변이형 원인 물질과 염기치환형 직접 및 간접돌연변이형 원인 물질에 의하여 오염되어 있음이 밝혀졌다 또한 제 4지점의 시료에서는 S9 mix존재 및 비존재 하에서 TA98세포주가 양성반응을 나타내어, 이 지점에 대한 변이원성의 돌연변이형은 fram shift형의 직접 및 간접 돌연변이임을 시사해주고 있다. 그러나 7월 이후에는 변이원성이 관찰되지 않았는데, 이는 1998년의 경제성장률의 저하에 기인된 것으로 생각되었다. 한편, 주거지역에 인접한 제 5-10지역의 시료에서는 전 조사기간에 걸쳐 변이원성이 관찰되지 않았는데, 이는 주된 오염원이 생활하수인 이들 지역의 강물이 변이원성 물질에 의해 오염되어 있지 않았음을 시사해 주고 있다.

하폭으로 평균된 2차원 동수역학 수치모형을 수입하였다. 수심방향으로 좌표변환하여 자유수면과 하상의 불규칙성에 대한 영향을 최소화하였다. 지배방정식의 이송항은 풍상차분기법을 이용하여 유속과 염분의 이송현상이 잘 표현되도록 하였다. 또한 흐름방향으로는 양해법을, 수심방향으로는 음해법을 사용하여 수심방향 격자증분이 매우 작기 때문에 야기되는 시간증분의 제약에서 벗어나도록 하였다. 모형의 적용성을 검증하기 위해 자유수면변위, 속도 및 염도분포에 관한 계산결과

It is very important to interprete and simulate the variation of phytoplankton maximum region for the prediction and control of red tide. This study was composed of two parts, first, the hydrodynamic simulation such as residual current and salinity diffusion, and second, the ecological simulation such as phytoplankton distribution according to freshwater discharge and pollutant loads. Without the Nakdong river discharge, residual current was stagnated in inner side of this estuary, and surface distribution of salinity was over 25psu. On the contrary, with summer mean discharge, freshwater stretched very far outward and some waters flowed into Chinhae Bay through the Kadok channel, and low salinity extended over coastal sea and salinity front occurred. From the result of contributed physical process to phytoplankton biomass, the accumulation was occurred at the west part of this estuary and the Kadok channel with the Nakdong river discharge. When more increased input discharge, the accumulation band was transported to outer side of this estuary. The frequently outbreak of red tide in this area is caused by accumulation of physical processes. The phytoplankton maximum region located inner side of this estuary without the Nakdong river discharge and with mean discharge of winter, but it was moved to outer side when mean discharge of the Nakdong river was increased. The variation of input concentration from the land loads was not largely influenced on phytoplankton biomass and location of maximum region. When discharge was increased, phytoplankton maximum region was transferred to inner side of the Kadok channel. On the other hand, when discharge was decreased, phytoplankton maximum region was transferred to inner side of this estuary and chlorophyll a contents increased to over 20㎍/L. Therefore, if any other conditions are favorable for growth of phytoplankton, decrease of discharge causes to increase of possibility of red tide outbreak.

The estuary of Nakdong river is very influenced by the freshwater contained nutrients and organic materials. The response results of these influences are eutrophication and red tide outbreak in this region. Concentration of chlorophyll a was 0.78∼62.55㎍/L in February, 1.20∼21.29㎍/L in April, 1.88∼188.35㎍/L in June, and 0.78∼11.21㎍/L in August, respectively. The decrease of chlorophyll a is considered that residence time is shorten by increase of freshwater discharge, and unfavorable growth condition of phytoplankton is created by diffusion of low salinity and increase of turbidity. The phytoplankton maximum region located inner side of this estuary during winter season, whereas it was moved to outer side when mean discharge of the Nakdong river was increased. Therefore, the variation of phytoplankton maximum region was affected by input discharge from the Nakdong river basin.

It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from estuary barrage and basin etc. Mokpo sea area downstreams from a long river and two large basins, the Yongsan river and Yongam-Kumho basins discharging much of water through water gates for the purpose of flood control and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculations were carried out for the analysis of diffusion characteristics due to discharging operation, adapting the results of tidal current simulation ADI methord is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the mode of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.

Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.

This study was conducted to evaluate water quality in the Keum River estuary using principal component analysis. The results was summarized as follow; Water quality in the Keum River estuary could be explained up to 70.40% by three factors which were included in the inffluent loading by the Keum River and Kyungpo cheon(38.99%), seasonal variation and organic matter pollution(19.05%), sediment resuspension and internal metabolism(12.35%). For spatial variation of factor score, artificial pollutant loading is highest at st.1, below Keum River barrage, and decreases toward the outer sea. For annual variation of factor score, factor 1 was highly related to artificial pollutant loading, and it was greatly increased in 1994. Also, organic matter pollution, sediment resuspension and internal metabolism were increased to every year. is necessary to control the nutrient loading by Keum river and Kyongpo cheon for Water quality management of estuary.

우리나라 서남부지역은 금강, 만경강, 동진강, 영산강 및 이들 하구 담수호와 관련하여 용수수급에 있어 불균형을 이루고 있는 실정이다. 예를 들면, 금강하구호는 저수용량이 작기 때문에 많은 양을 바다로 버리고 있는 실정이다. 반면, 현재 건설중인 새만금호는 비교적 저수용량에 비하여 유입량이 적은 편이다. 그리고 영광, 영암의 경우와 같이 영산강 하류 지역은 용수수요량은 많고 공급량은 부족한 실정이다. 이러한 용수수급의 불균형을 해결하고, 수자원의 이용 효

This study was conducted to evaluate water quality utilizing principal component analysis in the Nakdong River Estuary. From the results of analysis, water quality in the Nakdong River Estuary could be explained up to 65.3 percentage by three factors which were included in river loading(wastes from the Nakdong River and rainfalls ; 39.1%), sediment resuspension(13.7%) and metabolism(12.5%). In the eastern part of estuary in flowing the Nakdong River, river loading factor score(factor 1)was higher than that in western part. Sediment resuspension factor score(factor 2) was high in shallow water, while metabolism factor score(factor 3) was high in deeper water. For seasonal variations of factors score, factor 1 was highly related to rainfall season.

본 연구의 목적은 수자원 이송체계가 복잡한 금강 하구호의 물수지를 분석하는 것이다. 이를 위해 본 연구에서는 금강하구호의 유입량 규모를 자연유황과 저수유황을 고려하는 두 가지 평가방법을 제시하여 가뭄 상황에 대해서도 대처할 수 있도록 하였다. 저수유황은 관측수문곡선의 홍수파를 제거하여 추정하였으며, 계산결과, 저수유황의 경우 목표년도 1996년부터 물 부족이 예상되었다.

In this paper, we have investigated the tidal characteristics of the Nakdongpo estuary. We have carried out the analysis of harmonic constant with the use of the recorded data on tidal level at the Gadeong Do tide station and analyzed the flow velocity data obtained by ourselves at two points in the Nakdongpo estuary. In addition, we have analyzed the variation of the mean-sea level. Typical items of the characteristics we have found are; (1) The principal harmonic constants and non-harmonic constants are shown in table 2. (2) Tide in this area shows the semidiurnal inequality. (3) The mean-sea level is shown to be depressed at the rate of about 1cm to the rise of 1 mbar of the atmospheric pressure. (4) (i) At K2 point, The E-W component of the velocty reveals the nature of progressive waves. The N-S component reveals the nature of stationary waves. (ii) At K3 point, The E-W component shows the characteristics of progressive waves to some degree. The N-S component shows a weak hint of stationary waves. (5) At K2 point, S-component is predominant due to the flow of river. At K3 point, E-component is predominant due to the Tsushima current.