• Journal of Wetlands Research
• /
• v.18 no.1
• /
• pp.68-75
• /
• 2016

A set of lab-scale polymer synthetic fiber packed column wetlands composing three columns (CW1, CW2 and CW3) with different hydraulic regimes, recirculation frequencies and pollutant loading rates, were operated in 2012. Synthetic fiber tested as an alternative wetland medium for soil mixture or gravel which has been widely used, has very high pore size and volume, so that clogging opportunity can be greatly avoided. The inflow to the wetland was artificial stormwater. All the wetlands achieved effective removal of TSS (94%~96%), TCOD (68%~73%), TN (35%~58%), TKN (62%~73%) and NH4-N (85%~ 99%). Particularly, it was observed that COD was released from the fiber during one distinct period in all wetlands. This was probably due to the degradation of polymer fiber, and the released organic matters were found to serve as carbon source for denitrification. In addition, with longer retention time and frequent recirculation, lower effluent concentration was observed. With higher pollutant loading rate, higher nitrification and denitrification rates were achieved. However, although organic matters were released from the fiber, the lack of carbon source was still the limiting factor for the system since the release persisted only for 40 days.

• Journal of Wetlands Research
• /
• v.17 no.2
• /
• pp.184-192
• /
• 2015

This study is a basic research for low maintenance constructed wetlands which can prevent water quality deterioration due to wetland soils. The purpose of this study is to analyze water quality control mechanisms of constructed wetland on the artificial ground which installed the modular revetment structure(MRS), a device that separates water and soil. This study was then conducted with two different wetland mesocosms (a treatment plot and a control). These mesocosms were monitored to analyze effects of water quality control of the MRS. A treatment plot was built, and separated into soil and water, by filling the MRS with the decomposed granite soil in the mesocosm made of rubber material. A control plot was built where the decomposed granite soils were exposed to water by leaving the soil on the bottom of the mesocosm made of rubber material. Water quality was then analyzed by using Kolmogorov-Smirnov Z examination which then showed that pH, BOD, SS, Chl-a, T-P, T-N had statistically valid difference between a container with the MRS and one without it. According to the analysis of the water quality, the temperature and the EC level came out similarly and both mesocosm showed same level on pH and DO. A treatment plot had higher levels of BOD, SS Chl-a, and T-P. A control plot's T-N value was little lower than that of the treatment plot. This study suggests method of constructed wetlands using the MRS prevents problems occurring in wetland soils: aridity of wetlands by soil erosion, eutrophication, and algal blooms due to nutrients released from wetland soil. These functions of constructed wetland with the MRS increase aesthetic, ecologic, social, and economic value of the wetland. Outcomes of this research will later enable more proficient way of stabilizing water quality and provide data for planning low maintenance constructed wetlands.

• Korean Journal of Ecology and Environment
• /
• v.36 no.4 s.105
• /
• pp.391-402
• /
• 2003

Last 20 years have witnessed many studies dealing with effects of elevated $CO_2$ on terrestrial ecosystems. However, fewer efforts have been made to elucidate effects on wetland ecosystems, although they play a key role in global biogeochemical cycles. This review synthesizes published data to reveal effects of elevated $CO_2$ on wetland plants. In particular, we focused on the changes in primary production, community structures, evapotranspiration, and nutrients in plants. Many studies have reported increases in primary production in individual plants, but we could not conclude that this will lead to increases in carbon sequestration in wetland ecosystems. The reasons include transport of photosynthates into belowground parts, speciesspecific responses, interaction among different species, and limitation of other nutrients. However, elevated $CO_2$ increased transpiration rates in many wetland plants, suggesting substantial influences on water budgets of wetlands. In addition, similar to terrestrial ecosystems, elevated $CO_2$ increased C/N ratio of many plants, which may impede organic matter decomposition in the long term. However, further information on dynamics of belowground carbon supplied from wetland plants is warranted to assess effects of elevated $CO_2$ on wetland carbon cycle accurately.

• Journal of Wetlands Research
• /
• v.14 no.1
• /
• pp.35-45
• /
• 2012

In order to characterize the habitat trait and vegetation structure of M. chejuense(Ophioglssaceae), endangered plant in Korea, we set 12 permanent quadrats in Jocheon-Sunhyul Gotzawal Wetland Region of Jeju Island, and surveyed the temporal pools, vegetation structure and counted the population size of the endemic rare plant. M. chejuense distributed in the vernal pools with a variety of shape, area of 150-$400m^2$, depth of 0.4-2.0m and slope of 3-$10^{\circ}$, at altitude of 88-165m in lowland area in Gotjawal Wetland Region, Jeju Island. The soil has a thin layer and high water content all the seasons. The population appeared with a density range of 1-423/pool in the boundary area of the wetlands under higher tree coverages(80-100%) in the deciduous forest communities. Vegetation wsa classified into five plant communities such as Ulmus parvifolia community, Cudrania tricuspidata community, Rosa multiflora community, Ardisia japonica community, Ophiopogon japonicus community. These results means that M. chejuense potentially has a shortage to evergreen plant succession, litter accumulation and water drainage, thus it is need to sustainable wetland environmental condition in the deciduous forest community for its sounded conservation.

• The Korean Journal of Ecology
• /
• v.23 no.3
• /
• pp.201-209
• /
• 2000

The flora, distribution area, vegetation structure, annual net primary production, and nutrient uptake of the vascular hydrophytes, hygrophytes and mesophytes were investigated in the wetlands of the Asan-Lake, Chungchongnam-do and Kyonggi-do, Korea from March to October in 1997 to reveal the correlation between the plant community and the lake environment. The flora was composed of 38 families, 89 genera, 106 species, 14 varieties or total 120 kinds of the vascular plants. The life from of the hydrophytes were classified as 14 kinds of emergent plants, 5 kinds of submerged plants, and 4 kinds of free-floating plants, respectively. The number of species was various to 4 ∼85 kinds in each site. The dominant species was Zizania latifolia, and the importance values of Zizania latifolia, Typha orientalis, Phragmites communis, and Spirodela polyrhiza were 39.58, 14.90, 13.97, and 7.64, respectively. The distribution area of the emergent hydrophytes, hygrophytes, and mesophytes was 49.3 ㏊ (90.5%), and free-floating plants was 5.2 ㏊ (9.5%), whereas the floating-leaved and submersed plants were rare. Annual net production of the emergent hydrophytes, hygrophytes, and mesophytes was 547.9 ton D.W./yr (98%), and those of the free-floating plants was 10.5 ton D.W./yr (2%), and 558.4 ton D.W./yr in the whole lake ecosystem. The total uptake of nitrogen and phosphorus by the vascular plants was 7,099 and 1,891 ㎏/yr in the whole lake ecosystem.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.6
• /
• pp.353-360
• /
• 2010

The Kyunggi Bay in mid-west of Korea is a relatively large estuarine system that connects the Han River system with Yellow Sea. Due to macro-tidal range of more than 8 m, the urban estuary shows deep tidal channels and wide tidal flats. Since last 30 years, the coastal development is undergoing, yielding noticeable change in environment. Particularly the tidal flat dynamics are generally accepted as being related with tidal residual flows in this area (Kim et al., 2009). We have estimated the annual variation and vertical structure of residual currents with one-year long observed flows in two major tidal channels of Kyunggi Bay. The moving average method and tidal current harmonic analysis yield nearly the same results on residual flow. The residual flow in Jangbong channel ranges from 20 cm/s in summer to 30 cm/s in winter. It is noticeable that the residual flow in Jangbong channel is flood dominant throughout the year, while the flow in Seokmo channel is ebb-dominant residual flow with current speed range of 20-40 cm/s. Due to the baroclinic response of relatively shallow estuary, significant reduction of energy in bottom layers have been observed, indicating the importance of residual circulation to the tidal flat behavior.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.52 no.2
• /
• pp.110-126
• /
• 2024

This study conducted a classification of small-scale biological habitats created in Seoul to analyze and synthesize location characteristics, habitat structure, biological habitat functions, and threat factors of representative sites, as well as derive creation and management problems according to the ecological characteristics. The aim was to suggest improvement measures and management items. Data collected through a field survey was used to categorize 39 locations, and 8 representative sites were selected by dividing them into location, water system, and size as classification criteria for typification. Due to the characteristics of each type, the site was created in an area where amphibian movement was disadvantageous due to low or disconnected connectivity with the hinterland forest, and the water supply was unstable in securing a constant flow and maintaining a constant water depth. The habitat structure has a small area, an artificial habitat structure that is unfavorable for amphibians, having the possibility of sediment inflow, and damage to the revetment area. The biological habitat function is a lack of wetland plants and the distribution of naturalized grasses, and threats include the establishment of hiking trails and decks in the surrounding area. Artificial disturbances occur adjacent to facilities. When creating habitats according to the characteristics of each type, it was necessary to review the possibility of an artificial water supply and introduce a water system with a continuous flow in order to connect the hinterland forest for amphibian movement and locate it in a place where water supply is possible. The habitat structure should be as large as possible, or several small-scale habitats should be connected to create a natural waterfront structure. In addition, additional wetland plants should be introduced to provide shelter for amphibians, and facilities such as walking paths should be installed in areas other than migration routes to prevent artificial disturbances. After construction, the management plan is to maintain various water depths for amphibians to inhabit and spawn, stabilize slopes due to sediment inflow, repair damage to revetments, and remove organic matter deposits to secure natural grasses and open water. Artificial management should be minimized. This study proposed improvement measures to improve the function of biological habitats through the analysis of problems with previously applied techniques, and based on this, in the future, small-scale biological habitat spaces suitable for the urban environment can be created for local governments that want to create small-scale biological habitat spaces, including Seoul City. It is significant in that it can provide management plans.

• Journal of Wetlands Research
• /
• v.25 no.2
• /
• pp.159-165
• /
• 2023

This study measured the ecological niche overlap between two deciduous oak species(Quercus acutissmia and Q. dentata) according to the change in growth responses after treating with the moisture and nutrient contents of the soil at four gradients, and interpreted the degree of competition between the two oak species by ordination method. In the moisture environment gradient, the ecological niche overlap of the two species was high in the photosynthesis-related leaf organs and low in plant architecture such as shoot length. In addition, in case of competition between two oaks, Q. dentata was remarkably dominant in soil moisture gradient, but Q. acutissimia slightly was slightly advantageous over Q. dentata in the soil nutrient gradient. These results show that even in a similar taxonomical group growing in a similar habitat, the response to the organ system of the plant varies depending on the type of environment factor, resulting in different competitive differences among plants.

• Journal of Wetlands Research
• /
• v.26 no.2
• /
• pp.139-146
• /
• 2024

Various injection materials, such as asphalt-based injection materials, urethane-based injection materials, cement- based injection materials, and acrylic-based injection materials, are used for the repair of aged conduits and underground structures with cracks. In this study, research was conducted on an environmentally friendly acrylic- based leak repair material that exhibits good curing properties even in humid conditions and stability in temperature fluctuations. To compare the performance of the improved acrylic leak repair material with the existing acrylate injection material, experiments were conducted using KS standard methods, including underwater length change rate tests, underwater leakage resistance tests, and chemical performance tests. The comparative experiments revealed that the improved acrylic leak repair material showed no changes in shrinkage due to humidity, temperature variations, or chemical reactions compared to the existing acrylate injection material. In the underwater resistance test, the improved acrylic leak repair material did not show any leakage. Additionally, to assess the environmental impact of the improved acrylic leak repair material, acute fish toxicity tests and acute oral toxicity tests were conducted, and the results showed no mortality and no specific concerns with the test specimens. The experimental results led to the conclusion that the improved acrylic leak repair material is considered to be superior in performance, environmentally safe, and harmless to the human body. Based on various experimental results, it is inferred that the improved acrylic leak repair material is suitable for use as a repair material for cracks in manholes and underground structures compared to the existing acrylate repair material. This study aims to propose valuable data for future technological development by evaluating the applicability of acrylic leak repair materials.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.879-883
• /
• 2005

우리나라는 하천유역의 도시화 추세 속에 불투수층의 증가로 빗물의 일시 유출로 인한 홍수발생으로 많은 인명과 재산피해가 발생하고 있어 방재적 차원에서의 수자원관리가 시급한 실정이다. 또한, 초기 빗물과 합류식 하수도의 월류수에 의한 하천, 호소, 및 습지의 수질오염문제도 많이 발생하고 있다. 이러한 문제를 해결하기 위하여 콘크리트로 제작된 PC 지하식 빗물저류시설로서 상부의 공간은 공원, 운동장, 주차장 등 다양하게 이용하면서 방재와 치수를 가능케 할 수 있다. 또한, PC 콘크리트 빗물저류조는 현장 타설이 아닌 PC콘크리트 블록을 현장에서 조립하여 시공기간이 대폭적으로 단축되고, 작업환경 및 주변환경을 개선시킬 수 있다. 또한, 지하수의 보전, 회복을 위한 빗물저류 침투 시설 역할도 수행하여 비상용수를 확보하고 여름철 홍수 시 빗물을 가두어 재해를 방지하는 등의 다목적 시설로 활용된다. 지하 매립형 빗물저류조는 기존의 암거설계기준을 참조하여 일본의 내진설계 기준을 반영하였으며, 고강도 콘크리트를 사용하여 강도 또한 뛰어나다. 그리고 시공이 간편하고 공기의 단축에 탁월한 효과를 나타내며, 빗물저류조 설치는 다음과 같은 특징이 있다. 1. 지하저류형 빗물저류조 시설로 설계되어 토지의 효과적인 이용이 기대된다. 2. 공사기간이 짧아 경제적이다. 3. 안정된 구조체이다. 4. 부지의 형태에 맞춘 시공이 가능하다. 5. 소규모에서 대규모의 유수지까지 광범위하게 대응이 가능하다. 6. 방재역할 수행 및 빗물이용의 역할을 담당할 수 있다. 7. 불투수층이 증가하고 있는 도시지역에서 적극 활용가능하다.로 판단된다.한 예비방류의 시행과 강우종료 후에도 이수용량에는 손실이 없는 저수지의 관리방안의 지침이 되는데 효율적이라 판단되었다. 방법을 개발하여 개선시킬 필요성이 있다.>$4.3\%$로 가장 근접한 결과를 나타내었으며, 총 유출량에서도 각각 $7.8\%,\;13.2\%$의 오차율을 가지는 것으로 분석되어 타 모형에 비해 실유량과의 차가 가장 적은 것으로 모의되었다. 향후 도시유출을 모의하는 데 가장 근사한 유출량을 산정할 수 있는 근거가 될 것이며, 도시재해 저감대책을 수립하는데 기여할 수 있을 것이라 판단된다.로 판단되는 대안들을 제시하는 예비타당성(Prefeasibility) 계획을 수립하였다. 이렇게 제시된 계획은 향후 과학적인 분석(세부평가방법)을 통해 대안을 평가하고 구체적인 타당성(feasibility) 계획을 수립하는데 토대가 될 것이다.{0.11R(mm)}(r^2=0.69)$로 나타났다. 이는 토양의 투수특성에 따라 강우량 증가에 비례하여 점증하는 침투수와 구분되는 현상이었다. 경사와 토양이 같은 조건에서 나지의 경우 역시 $Ro_{B10}(mm)=20.3e^{0.08R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며