• Title/Summary/Keyword: estuary restoration

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The Gate Operation for Bolstering up Fish Migration in the Nakdong River Estuary (낙동강하구의 어류 이동성 향상을 위한 수문운영 방안 제안)

  • Jeong, Seokil;Han, Jeong-Ho;Lee, Ji-Young;Kim, Hwa-Young
    • Korean Journal of Environment and Ecology
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    • v.36 no.5
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    • pp.468-480
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    • 2022
  • Although the construction of the Nakdong River Estuary Barrage (NEB) improved the water supply in the region, it cut off the longitudinal connectivity of the estuary aquatic ecosystem. Thus, the social demands for opening the NEB have been continuously raised, and the efforts to restore the aquatic ecosystem of the Nakdong River estuary began in 2017. Many fish species have inhabited the Nakdong River estuary. Since their habitat and migration characteristics vary widely, the sluice gate operation considering them is essential for the restoration of the aquatic ecosystem. Therefore, in this study, we monitored the fish species living and migrating in the Nakdong River estuary and analyzed the possibility of smooth movement of for each fish species by calculating the average flow velocity according to the type and the height of the gate opening. Moreover, we selected the target fish species for each month and suggested the sluice gate operation according to the depth of the main habitat to present the measures that are ideal for optimal restoration of the aquatic ecosystem in the Nakdong River estuary area.

Mistakes Made, Lessons Learned: The Eulsukdo Wetland Restoration Program

  • Lineman, Maurice J.M.;Do, Yuno;Kim, Ji-Yoon;Joo, Gea-Jae
    • Journal of Environmental Science International
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    • v.23 no.8
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    • pp.1523-1536
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    • 2014
  • Restoration is the process of reducing or reversing damage to an ecosystem so that it can function in its original manner. However, many restoration programs do not achieve this. In the Nakdong Estuary, the largest migratory nesting site in the center of the East Asian-Australasian flyway, an estuarine barrage was constructed in the 1980s that required site restoration following its completion in 1987 and the expansion of several large industrial complexes(Noksan and Jangrim) and a residential development(Myeongji). The goal of the restoration was to restore the function of the wetland to its pre-disturbance state. To achieve this, a restoration program was designed consisting of three stages. The first stage(1993-1995), saw the construction of three artificial wetlands(Shinhori, Daemadeung, and Eulsuk), the second(2003-2005) involved the dredging and returning of farmed lands to their natural state, and the third(2008-2012) focused on the rehabilitation and vegetation development of the wetlands. However, the project has not achieved all of the desired goals, and it is an example of the lapses in ecological restoration following anthropogenic disturbance. Issues that resulted in an incomplete restoration included the timing of the stages, noncompliance with the restoration plan, not directly monitoring the restoration or continuing the monitoring following completion of the development project, and the political subversion of the restoration plan. For the success of the restoration plan, it is necessary to avoid mistakes such as inconsistent monitoring, unequal levels of stakeholder involvement, and political interference.

Monitoring on Bolboschoenus planiculmis Restoration in Nakdong River Estuary: Implications for Wetland Restoration Using Shoot Transplantation (낙동강하구 새섬매자기(Bolboschoenus planiculmis) 복원 모니터링: 식물체(shoot) 식재를 이용한 습지복원)

  • Gu-Yeon Kim;Hee Sun Park;Hwa Young Kim;Ji-Young Lee
    • Korean Journal of Ecology and Environment
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    • v.55 no.4
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    • pp.406-414
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    • 2022
  • Bolboschoenus planiculmis has been acknowledged as a key species in whooper swans (Cygnus cygnus) habitat by providing food for this migratory waterfowl. B. planiculmis wetlands are being degraded by water shortages and salinization caused by anthropogenic activities and climate changes. In 2004, the distribution of B. planiculmis in the tidal flats of the Nakdong Estuary was 2,475,568 m2, and in 2021, the distribution area was 798,731 m2, which decreased by 32.3%. In order to restore the degraded B. planiculmis wetlands, shoot transplantation and seed sowing were tentatively used in three places with different salinity and water levels. The average density per unit area in September at the optimal growth period after planting were A (fresh water level 50 cm) 58±15.65 m-2, B (brackish water level 0~5 cm) 188±63.83 m-2, C (brackish water level 0 cm or less) 188±45.13 m-2. The tubers were observed as A 0 g dw m-2, B 25.32±2.94 g dw m-2, and C 13.39±0.91 g dw m-2. Tubers were distributed in the soil, with only 3.0% at the 10~20 cm depth but 97.0% at the 0~10 cm depth. In contrast, the germination rate of B. planiculmis seeds was observed to be 0%. Results of this study provide technical support for the restoration of B. planiculmis wetland and the improvement in the quality of whooper swans habitat.

Flora of Three River Estuary Areas of the East Coast, Gangwon-do (강원도 동해안 3개 하천 하구역 일대의 식물상)

  • Jung, Hee-Jin;Cheon, Kyeong-Sik;Ok, Gil-Hwan;Yoo, Ki-Oug
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.15 no.2
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    • pp.57-75
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    • 2012
  • This study was carried out to investigate the flora of estuary regions, Namdaecheon, Jusucheon, and Maeupcheon, placed in the east coast of Gangwon-do. The vascular plants were summarized as 441taxa, including 90 families, 277 genera, 388 species, 2 subspecies, 35 varieties, and 6 forms. Number of species in each investigated region was 271taxa of Namdaecheon, 247taxa of Jusucheon, and 285taxa of Maeupcheon, respectively. Among the investigated 441taxa, 7 Korean endemic, 5 rare plants and 37 specially designated plants by Ministry of Environment were also included. Aquatic and hydrophyte plants were collected 41taxa, and the thinophyte and halophyte plants were investigated 22taxa. The naturalized plants were 59taxa, and the percent of naturalized plant species was estimated as 13.3%. Based on the floristic composition, Maeupcheon was estimated as well conserved estuary region among the investigated 3 rivers.

Priority Determination of the Projects for Ecological Restoration of the Stream : Case Study for Han River Estuary (생태하천 복원사업 우선순위 선정에 대한 연구: 한강하구를 중심으로)

  • Seonuk Baek;Junhak Lee;Seungmin Lee;Haneul Lee;Hung Soo Kim;Soojun Kim
    • Journal of Wetlands Research
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    • v.25 no.1
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    • pp.64-73
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    • 2023
  • Before 2022, there was a lot of confusion in the process of planning and implementing the projects for ecological restoration of the stream due to dualization the principal agent of stream management. Because the Ministry of Environment took charge of the project in 2022, securing the health of aquatic ecosystem of stream became an essential factor in the project. Therefore, in this study, the streams that require the project for ecological restoration was selected in Han River estuary, where it is essential to secure the health of the stream aquatic ecosystem as blackish water zone and Ramsar wetland are located. Physical, chemical, spatial/humanistic, health of aquatic ecosystems evaluation indexes were calculated based on the detailed facts and figures of the project for ecological restoration of the stream in the beginning. Ranking, re-scaling, z-score, and t-score normalization methods were applied to the calculated evaluation index, and the values were compared and analyzed. After that, the entropy weight method was applied to each evaluation index. Through this process, the streams(Mokgamcheon, Anyangcheon etc.) that require the project for ecological restoration were selected for the purpose of securing the health of the aquatic ecosystem in Han River estuary. The result of this study can be used as basic research data in the process of selecting the priority determination of the projects for ecological restoration of the stream.

A Study on Precise Tide Prediction at the Nakdong River Estuary using Long-term Tidal Observation Data (장기조석관측 자료를 이용한 낙동강 하구 정밀조위 예측 연구)

  • Park, Byeong-Woo;Kim, Tae-Woo;Kang, Du Kee;Seo, Yongjae;Shin, Hyun-Suk
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.6
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    • pp.874-881
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    • 2022
  • Until 2016, before discussions on the restoration of brackish water of the Nakdong River Estuary started in earnest, the downstream water level was predicted using the data of existing tide level observatories (Busan and Gadeokdo) several kilometers away from the estuary. However, it was not easy to carry out the prediction due to the dif erence in tide level and phase. Therefore, this study was conducted to estimate tide prediction more accurately through tidal harmonic analysis using the measured water level affected by the tides in the offshore waters adjacent to the Nakdong River Estuary. As a research method, the storage status of observation data according to the period and abnormal data were checked at 10-minute intervals in the offshore sea area near the Nakdong River Estuary bank, and the observed and predicted tides were measured using TASK2000 (Tidal Analysis Software Kit) Package, a tidal harmonic analysis program. Regression analysis based on one-to-one comparison showed that the correlation between the two components was high correlation coef icient 0.9334. In predicting the tides for the current year, if possible, more accurate data can be obtained by harmonically analyzing one-year tide observation data from the previous year and performing tide prediction using the obtained harmonic constant. Based on this method, the predicted tide for 2022 was generated and it is being used in the calculation of seawater inflow for the restoration of brackish water of the Nakdong River Estuary.

A Study on Fish Fauna and Fish Habitat -Downstream of Singok Submergerd Weir in Han River Estuary- (한강하구 생물자원 및 서식처 특성에 관한 연구 -신곡수중보 하류 한강하구의 어류상-)

  • Moon, Byeong Ryeol;Jeon, Sook Lye;Hyun, Moon Sik;Hwang, Jong Seo;Choi, Jun Kil
    • Journal of Environmental Impact Assessment
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    • v.20 no.5
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    • pp.757-764
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    • 2011
  • This study is performed to clarify the fish fauna and fish habitat of downstream of Singok submerged weir within Han River estuary during April ~ December 2009. It was studied at the nine sites of Han River estuary area. The three of them were located in the mainstream of Han River and six of them were located in three wetlands which as Sannam, Janghang and Dolbangguji. Total fish fauna was identified as 9 order 15 family and 38 species (2,230 individuals). It was divided as 8 order 11 family 28 species from three sites in the mainstream of Han River and as 5 order 8 family 19 species in waterways at mud flats of three wetlands. It was made up the fish fauna as 3 order 4 family 12 species during the survey period at the waterways in the rice paddies. Hemibarbus labeo was dominant species in the whole research sites and waterways at mud flats. Carassius auratus was dominant species in the waterways between rice paddies and Chelon haematocheilus was dominant species in mainstream of Han River estuary.

Topographical change of sandbar and vegetation settlement in Jang-Hang wetlands for Han River Estuary Wetlands Restoration (한강 하구 습지복원을 위한 장항습지의 사주 지형변화 및 식생정착)

  • Ahn, Hong-Kyu;Kim, Si-Nae;Chung, Sang-Joon;Lee, Dong-Jun;Lee, Sam-Hee
    • Journal of Wetlands Research
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    • v.14 no.2
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    • pp.277-288
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    • 2012
  • Estuary is unique habitat ground under substantial changes of water quality, river side, bed material, and micro topography. Construction of SinGok underwater weir with excessive dredging for downstream of weir has changed hydraulic conditions of Han River. This study investigates spatial changes of estuary and expansion process of vegetation on sandbar for JangHang estuary in Han River through analysis of physical and ecological characteristics. As a result of investigation, we found that area of sandbar in JangHang estuary is expanded six times compared between 1985 and 2006, and area of Phragmites australis is gradually decreased while area of Salix subfragilis Anderson. is increased. Also the analysis result of soil layer shows that the Jang-Hang wetlands are created by effect from river, and woody plants are settled from middle part of wetlands, then spread to upper and lower part of wetlands.