• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.70-80
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• 2007

This study was surveyed from January to september, 2007 in order to evaluate the function of coastal wetland as a ecological axis in korea peninsula. Assessment was done by RAM (Rapid Assessment Method). RAM is consisted of total 8 contents and divided into high, moderate, low. The preservation grade of RAM is divided into 4 grades; absolute preservation, preservation, improvement and improvement or restoration. Throughout survey on total 14 wetlands of marine, estuary wetland and back marsh which are distributed in west coast in chung-nam province, their function was assessed. As result, total all the 14 wetlands were judged as preservation grade by assessment of 8 functional contents. The function of wetlands assessed as preservation grade showed high in water quality protection and improvement. Also, showed high in vegetation diversity, wildlife habitat and aesthetic recreation. Meanwhile, showed low in ground water recharge, Shoreline/Stream Bank Protection, Flood/Stormwater storage and Flood flow alteration. Of wetlands evaluated as preservation grade, Dae-ho, Sinduri, Bu-Nam lake, Sowhang dune and keum river estuary were assessed as absolute preservative area owing to habitation of international protection species and endangered species. These wetlands are essential to be managed continuously as a area having high ecological value. Farther, this wetlands will be done as a axis of ecological network related to land ecosystem.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.33-42
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• 2019

In this study, the channel and floodplain widths are indirectly measured for three different watersheds using satellite images to reflect the shape of Korean channels in the Soil and Water Assessment Tool (SWAT) model. For measuring the channel and floodplain widths, multiple satellite images were referred to ensure the widest width of certain points. In the single channel, the widths at the multiple points were measured. Based on the measured data, the regression equations were derived to estimate the channel and floodplain widths according to watershed areas. Applying these developed equations, this study evaluated the effect of the change of channel and floodplain widths on the SWAT simulation by comparing to the measured streamflow data. The developed equations estimated larger channel width and smaller floodplain compared with those calculated in the current SWAT model. As shown in the results, there was no considerable changes in the predicted streamflow using the current and developed equations. However, the flow velocity and channel depth calculated from the developed equations were smaller than those of the current equations. The differences were caused by the effect of different channel geometries used for calculating the hydraulic characteristics. The channel geometries also affected the water quality simulation in channels because the hydraulic characteristics calculated by the channel geometries are directly related to the water quality simulation. Therefore, application of the river cross-sectional regression equation reflecting the domestic stream shape is necessary for accurate water quantity / quality and water ecosystem simulation using hydrological model.

• Ecology and Resilient Infrastructure
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• v.11 no.2
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• pp.35-42
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• 2024

The aquatic ecosystem of rivers, where various biological groups inhabit, is influenced by suspended sediment. However, there is a lack of quantitative and objective methods and criteria for evaluating this impact. The purpose of this study is to analyze through experiments the effects of suspended sediment on Glyptotendipes tokunagai, a benthic invertebrate in rivers. Experiments were conducted to investigate the survival count of individuals exposed to varying suspended sediment concentrations (turbidity) and exposure durations. Various regression analysis methods were performed on the experimental results to propose a model for evaluating the impact of suspended sediment on Glyptotendipes tokunagai. The coefficient of determination (R-squared) of the proposed model was 0.903, indicating a high degree of fit. The findings of this study could serve as foundational data for assessing the influence of suspended sediment on various organisms inhabiting rivers.

• Journal of the Korean association of regional geographers
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• v.21 no.2
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• pp.355-363
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• 2015

DMZ(Demilitarized Zone) created as part of the Armistice Agreement is important zone in the way that historic and eco-cultural value as well as military and political image of this are remarkable. Furthermore, the concern of DMZ has been rising at home and abroad. Even though various studies on this subject have been constantly spurring according to the significance, the practical researches on spatial range of DMZ are very weak. The Purpose of this research is to show the factual spatial extent of DMZ from the mouth of the Imjingang River in the west to the town of Goseong in the east. This study proved the area of corresponding DMZ is approximately $570km^2$ contrary to the previous studies and claims it is difficult to measure the actual length of MDL(Military Demarcation Line) regarded as 155mile in this situation of Korea peninsula.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.43-50
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• 2020

The Doam Lake watershed is one of the non-point source management areas announced by the Ministry of Environment, and is a constant problem for the stream ecosystem dut to Storm water. In this study, a total of 48(rainfall) and 47(non-rainfall) sites were investigated for the entire watershed (Samyangcheon, Chahangcheon, Hoenggyecheon, Yongpyeongcheon, Songcheon, Lake Doam) on August 15, 2019 and on October 18, 2019 to estimate the source of turbid water in the Doam Lake watershed. Subsequently, water quality analysis was performed on Suspended Soild (SS), Turbidity, Total Phosphorus (TP), Total Nitrogen (TN), and Biochemical Oxygen Demands (BOD) and correlation among water quality parameters was analyzed based on the analyzed samples. As a result, most of the turbid water generated during rainfall was in highland fields. During rainfall, Hoengyecheon had the highest average SS concentration among all streams, and during non-rainfall, the average SS concentration was highest in Yongpyeongcheon, so the two stream were selected as vulnerable areas. However, since Yongpyeongcheon may be a temporary phenomenon due to river construction, additional continuous monitoring is required. Therefore, in the Doam Lake watershed, intensive management is required for vulnerable areas.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.33-41
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• 2015

In this study, an optimal improvement method of stream channel structure is presented for the enhancement of fish habitat suitability by genetic algorithm. The correlation between fish habitat suitability and physical disturbance in stream is analyzed according to the changes of hydraulic characteristics by channel structure rehabilitation. Zacco koreanus which is an indicator fish of the soundness of aquatic ecosystem was selected as a restoration target species by investigating the community characteristics of fish fauna and river environments in Wonju stream. The habitat suitability is investigated by PHABSIM with the habitat suitability index of Zacco koreanus. Hydraulic analysis by HEC-RAS and physical disturbance evaluation in stream are carried out. The optimal channel width modified for the enhancement of fish habitat suitability is provided. The correlation analysis between habitat suitability and physical disturbance with the change of hydraulic characteristics by channel modification showed that the proper channel modification enhanced fish habitat suitability and mitigated physical disturbance in the stream. The improvement of physical disturbance score by the channel structure rehabilitation for the enhancement of fish habitat suitability was confirmed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.33-44
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• 2019

Due to the recent climate change realization (timing, rainfall pattern changes), the flow regime is changing according to the watershed. The long-term change of flow regime is causing a significant change in structure and function of aquatic ecosystems. However, there is no analysis from the viewpoint of the aquatic ecosystem including flow rate alteration and ecological characteristics as well as the climate change connection in Korea yet. Therefore, We quantitatively assessed the impact of present-future flow regime alteration due to climate change on the Pseudopungtungia nigra habitat in the Mankyung river and floodplain area. As a result, it was confirmed that extreme hydrological conditions such as flood and drought are intensified in the future than the present. Especially, the changes of flow regime characteristics were clarified by comparing and analyzing the magnitude, frequency, duration, rate of change, and by linking flow regime characteristics with physical habitat analysis, it could be suggested that climate change would significantly increase the risk of future ecological changes.

• Journal of Marine Bioscience and Biotechnology
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• v.3 no.1
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• pp.1-6
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• 2008

Angola has a coastline of about 1,650 km long. Two diverging current namely, the Angola current with its warm water from the north and the cold Benguella Current in the south create a strong up-welling with a high productive ecosystem for marine resources. The area from Lobito to the mouth of the Cunene River, also known as the Southern fishing zone is by far the most productive of Angola's fishing zones. In 1977, the total potential of its marine fisheries sector was estimated at more than 700,000 tonnes per annum. In 2003, the Total Allowable Catch (TAC) established for demersal species was 57,600 tonnes and 160,000 tonnes for pelagic species. The most important resources are various marine demersal and pelagic fish including pilchard and the Cape and Cunene horse Mackerel (Tranchurus capensis and T. trecae). Sardinellas (Sardinella aurita and S. maderensis) are fished in parallel with horse mackerel. The rest of the catches are mainly demersal spp. and some deep water crustaceans. The demersal sppecies consist of Hake (Merluccius polli and M. capensis) and the large eye dentex spp. Tunas are caught at certain times of the year whilst some marine shrimp are also harvested from the Angolan waters. Angola also has several high value freshwater fish species, exploited by about 255 fishers. Tilapia sp. is among the most important and abundant fresh water fish found in Angola. Other species include the catfish (Clarias gariepinus) and fresh water prawns (Macrobrachuin rosenbergii). Some aquaculture ponds have been established in the country side, but due to lack of investment, proper training and the impact of civil war have seriously limited developments in the sub sector.

• Journal of Korea Water Resources Association
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• v.46 no.3
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• pp.267-276
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• 2013

An Improvement of channel structure for sound fish habitat suitability enhancement is investigated. The restoration target species of Zacco Koreanus which is represented a sound aquatic ecosystem is selected by investigating results of the fish fauna and the river environments. The changes of lower channel width for enhancing suitability indices for water velocity and depth result in habitat suitability enhancement in general by PHABSIM simulation. The habitat suitability enhancement is not guaranteed consistently by the changes of lower channel is confirmed. The optimal lower channel widths at each reach are presented by genetic algorithm of optimization which is considering the enhancement of suitability indices for water velocity and depth with given instream flows. The suggested plan of the lower channel modification will contribute to the various projects for the environmental improvement of aquatic system.

• Journal of Wetlands Research
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• v.7 no.3
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• pp.67-73
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• 2005

At research, the river's water which the sewage treatment facility will ask growth suppression the algae in the artificial rivers which it is using or it researched the method for the removal of the algae which grew. At results, when 60ppm of Chlorine was put in, the possibility of getting the result where 90% chlorophyll-a was removed and LC50 was 0.8ppm. The algae did not create even after 20days by which uses prevent agent of creation of the algae. Controlling the chlorine almost there was not an extinction effect of the algae which was already in large quantities multiplied, with in the effect against an water ecosystem widely known it is not. The prevent agent could inhibit creation of the algae, but it was judged with the fact that the methods are directly applied to the field must be researched continuously.