• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.183-190
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• 2007

Soil layer in vegetation filter strip is one of the very important factor for reduction of non-point pollutants by physical, chemical and biological reactions of it through infiltration process. This study was carried out to prepare more effective vegetation filter strip through modification of soil layer for river water quality improvement. Therefore, the main aims of this study are to compare and evaluate normal (straighten type) and modified (step type) vegetation filter strip, which make artificially change the soil layer to improve infiltration ability, through bench scale experiments. In the results of this study, vegetation filter strip of step type is much more highly reduction effectiveness of pollutants in surface flow compared with normal vegetation filter strip. In case of below effluent, however, it appeared that the vegetation filter strip modified soil layer showed lower reduction effectiveness of pollutants than the general vegetation filter strip. This result was judged because effluent through the vegetation filter strip of step type passed bigger size of aggregate or sand than the vegetation filter strip of straighten type. If we compare it as a definition of pollutant load to estimate total amount of reduced pollutants by vegetation filter strip, reduced pollutants load by step type showed higher than those by straighten type because below effluent amount relied on total effluent amount was higher at step type (4%) than at straighten type (2%). In conclusion, the vegetation filter strip of step type to improve infiltration effect is much more reduction effectiveness of pollutants than vegetation filter strip of straighten type.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.369-383
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• 2016

A distributed watershed model CAMEL(Chemicals, Agricultural Management and Erosion Losses) was applied to a part of grazing grassland and vegetation buffer strip(VBS) located in Daegwanryeong, Korea. A set of scenario analyses was carried out for grassland and VBS with various combinations of VBS widths, soil textures and ground surface slopes. The simulation results indicate that annual direct runoff decreases with wider VBS and the removal efficiency of pollutants generally decrease with steeper slopes. The removal efficiency of sediment is not significantly different with VBS widths. For gentle and medium slopes($10^{\circ}$, $20^{\circ}$), the removal efficiency of TOC and TN is not significantly different with VBS widths. As for a steep slope($30^{\circ}$), however, the removal efficiency of TOC and TN increases with narrower VBS. The removal efficiency of TP is generally high except for medium and steep slope of sandy loam where the removal efficiency of TP increases with wider VBS. This result of TP is contrary to the results of TOC and TN due to the adsorption characteristics of phosphorus associated with fine sediment particles. It is expected that CAMEL can be used for evaluating the effectiveness of VBS to reduce non-point source pollution discharges.

• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.516-531
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• 2015

In this study, a software module to predict the effectiveness of vegetation buffer strip (VBS) has been developed for using with Chemicals, Agricultural Management and Erosion Losses (CAMEL), a distributed watershed model. Most basic functions for the VBS module are same as CAMEL except functions newly developed to implement sedimentation enhancement by vegetation and level spreaders. For verification of the VBS module, sensitivity analyses for length, roughness, soil and vegetation type of VBS were carried out using a test grid cell. The surface discharge of sediment are highly sensitive to the roughness coefficient of VBS. The removal efficiencies of VBS for the surface discharges of sediment and TP are generally high regardless of environment changes. The surface discharges of TOC and TN are highly sensitive to the length and soil of VBS. The removal efficiencies of VBS for the surface discharges of TOC and TN are generally lower than those of sediment and TP. The newly developed VBS module reasonably simulates the removal efficiencies of surface discharges that vary according to the environment changes. It is expected that this VBS module can be used for evaluating the effectiveness of VBS-based best management practices to be applied to reduce pollution discharges from various non-point sources.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.463-463
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• 2016

최근 도시물순환 복원 및 치 이수효과 증대를 위해 저영향개발기법(Low Impact Development) 연구가 활발하게 진행 중이다. 하지만 대부분이 수치모델을 활용한 설계프로그램 개발에 대한 연구에 집중되어 있는 실정이며, 이러한 프로그램을 활용한 설계 시 최적의 매개변수 결정에 한계가 있다. 이러한 이유로 본 연구에서는 건축형 LID 요소 중 하나인 식생여과장치(Planter Box)의 모형실험을 통해 프로그램 모의에 필요한 매개변수를 추정하고, 모의를 수행한 후 모형실험 결과와 프로그램 모의 결과를 비교하여 최종적으로 식생여과장치의 설계 매개변수를 산정하고자 한다. 식생여과장치의 모형실험을 위하여 가로 1.5m, 세로 1.5m, 높이 1.5m로 실험 장치를 제작하였으며, 강우-유출수 실험 전 시료의 침투율, 함수비 등을 체크한 후 지속시간 1시간의 재현빈도 5년, 10년, 20년, 50년에 해당하는 강우강도에 대해 실험을 수행하였다. 실험결과로 나타난 자료는 SWMM 모형과 비교분석해 모형에 적용된 매개변수의 적합성을 분석하였으며, 재현빈도 5년, 10년, 20년의 경우 $R^2$ 값이 0.88~0.97로 실험 값과 모의 값의 연관성이 높게 나타났으며, 재현 빈도 50년의 경우 0.7835로 비교적 연관성이 낮게 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.209-209
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• 2020

환경부 자료에 따르면 1990년대부터 2000년대 후반까지 국내의 도시면적은 696,239㎢ 증가했다. 도시지역에서의 불투수면적이 차지하는 비율은 25% ~ 80%로 적지 않은 비율을 차지한다. 따라서 도시면적이 증가하면 이는 불투수면적의 증가로 이어지며 이로인한 지표유출로 오염물질의 유입이 늘어나게 되면, 수질오염중 비점오염원이 차지하는 비중의 증가한다. 비점오염원으로 인해 발생하는 환경문제를 해결하기 위해 LID(Low Impact Develpment)시설에 대한 연구가 많이 진행되었다. 본 연구에서는 7년간의 선행 연구결과를 바탕으로 LID 시설별 오염물질 저감효율을 비교분석하였다. 용인 삼계리에 위치한 식생수로 오염지표들의 유입, 유출EMC를 토대로 제거 효율에 대한 평가를 해보면 TSS는 46%, BOD는 48%, COD는 56%. TN은 42% 그리고 TP는 58%가 나왔다. 용인 해곡동에 위치한 식생여과대의 경우 TSS는 83%, BOD는 45%, COD는 43%, TN은 39%, 그리고 TP는 62%가 나왔다. 마지막으로 전주에 위치한 식생체류지의 경우 TSS는 100%, BOD는 75%, TOC는 62%, TN은 67% 그리고 TP는 83%가 나왔다. 이들 자료를 바탕으로 효율성 평가를 해보면 먼저 식생수로의 경우 TP 저감 효율이 58%로 가장 높았으며 TN 저감 효율이 42%로 가장 낮았다. 식생여과대의 경우 TSS 저감 효율이 83%로 가장 높았으며 TN 저감 효율이 39%로 가장 낮았다. 마지막으로 식생체류지의 경우 TSS 저감 효율이 100%에 가까운 양질의 제거효율을 보여주었으며, TOC의 경우 67%로 제일 낮은 제거효율을 보였다. 위 결과를 토대로 판단을 해보면 식생체류지가 전반적으로 좋은 지표를 보였으며 대부분의 상황에 양호한 제거효율을 기대할 수 있다고 생각된다. 식생 LID시설은 자연친화적이며 강우유출과 오염물질을 제거할 수 있다는 장점이 있는 반면, 장치형 LID시설에 비해 넓은 부지면적을 필요로 하므로 설치 지역의 특성에 맞게 LID 시설을 시공하는것이 적절하다고 판단된다. 해당 연구결과는 향후 식생형 LID시설을 설계하는데 있어서 기초자료로 반영될 것으로 기대된다.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.100-109
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• 2016

Low impact development (LID) facilities are established for the purpose of restoring the natural hydrologic cycle as well as the removal of pollutants from stormwater runoff. Improved efficiency of LID facilities can be obtained through the optimized interaction of their major components (i.e., plant, soil, filter media, microorganisms, etc.). Therefore, this study was performed to evaluate the performances of LID facilities in terms of runoff and pollutant reduction and also to provide an optimal maintenance method. The monitoring was conducted on four LID technologies (e.g., bioretention, small wetlands, rain garden and tree box filter). The optimal SA/CA (facility surface area / catchment area) ratio for runoff reduction greater than 40% is determined to be 1 - 5%. Since runoff reduction affects the pollutant removal efficiency in LID facilities, SA/CA ratio is derived as an important factor in designing LID facilities. The LID facilities that are found to be effective in reducing stormwater runoff are in the following order: rain garden > tree box filter > bioretention> small wetland. Meanwhile, in terms of removal of particulate matter (TSS), the effectiveness of the facilities are in the following order: rain garden > tree box filter > small wetland > bioretention; rain gardens > tree box filter > bioretention > small wetland were determined for the removal of organic matter (COD, TOC), nutrients (TN, TP) and heavy metals (Cu, Pb, Cd, Zn). These results can be used as an important material for the design of LID facilities in runoff volume and pollutant reduction.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1378-1382
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• 2007

과거에는 치수적인 측면에서 하상과 둔치에 자생하는 식생이 홍수시 하천의 통수능을 줄인다는 이유로 기피 대상이 됐으나, 근래에 들어 생활수준의 향상과 더불어 국민의 여가생활에 있어서 하천의 친환경적인 역할이 증대되고 있다. 하천에서의 식생은 토사의 침식을 억제하여 탁도를 줄이며, 수중야생 동 식물들의 서식처를 제공하고, 제방의 식생은 제방의 안정에 기여한다. 뿐만 아니라 식생은 첨두홍수량을 줄이는데 기여하고, 유출에 의한 오염물질을 여과시킨다. 과거에는 하천 식생을 고려하기 위해 Manning 공식 등을 이용하여 단순히 경험적으로 조도계수만을 증가시키는 방법을 사용하였다. 단순히 조도계수를 증가시킬 경우, 식생이 수로에 존재하면 전체적인 흐름저항은 증가하지만, 하상 전단력은 감소한다는 개념과 맞지 않게 된다. 또한 기존 식생수로에 관한 연구의 초점은 주로 수직모형에 의한 수직 흐름구조 변화에 있어 왔다. 하지만 수직모형을 실제 자연하천에 적용하기란 쉽지 않고, 실무적인 측면에서 비실용적이다. 따라서 본 연구에서는 실무적으로 적용성 및 활용도가 높은, 식생항력 개념을 적용시킨, 수심 평균된 2차원 수치모형을 개발하였으며, 직선수로에 식재구간을 설정하여 식생에 의한 흐름특성 변화를 살펴보았다. 식생이 존재함으로써 수면의 상승이 유발되었고, 비식재 구간에서의 평균유속이 상대적으로 높은 증가율을 보였다.

• KCID journal
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• v.9 no.1
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• pp.103-111
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• 2002

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.264-272
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• 2007

Runoff of non-point pollutants has affected bad influence to water quality of river as reaching within short time. For this reason, reducing them prior to reaching aquatic systems or treating them after collection from discharge process of pollutants are desirable for efficient treatment of pollutants. This study was carried out to develop an ecotechnological method to prevent further aggravation of water quality by non-point source through vegetation filter strips. This study has placed a focus on improving infiltration capacity of soil for the optimum condition of vegetation filter strips. Therefore, we used titled soil filter strips instead of vegetation filter strips in this study. The three types of soil tilter strips were used in a bench scale experiment before applying to the field. The reduction efficiency of pollutants in soil filter strips (SS $84.5{\sim}92.5%$, BOD $67.9{\sim}80.6%$, T-N $43.4{\sim}76.6%$, T-P $40.6{\sim}87.4%$, Cu $28.3{\sim}48.1%$ Fe $92.1{\sim}97.7%$, Pb $81.4{\sim}97.3%$) was much higher than that of the controled group. And non-point pollutants reduction efficiency by soil filter strip's forms was estimated to be distinguishing in order of bio material, mixture of sand and gravel and lastly the whole gravel. In the event, the whole reduction efficiency of pollutants on the soil filter strips disclosed good results.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.221-230
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• 2016

Multi-functional floating wetland island (mFWI) was developed in order to prevent algal bloom and to improve water quality through several unit purification processes. A test bed was applied in the stagnant watershed in an urban area, from the summer to the winter season. For the advanced treatment, an artificial phosphorus adsorption/filtration medium was applied with micro-bubble generation, as well as water plants for nutrient removal. It appeared that the efficiency of chemical oxygen demand (COD) and total phosphorus (T-P) removal was higher in the warmer season (40.9%, 45.7%) than in the winter (15.9%, 20.0%), and the removal performance (suspended solid, chlorophyll a) in each process differs according to seasonal variation; micro-bubble performed better (33.1%, 39.2%) in the summer, and the P adsorption/filtration and water plants performed better (76.5%, 59.5%) in the winter season. From the results, it was understood that the mFWI performance was dependent upon the pollutant loads in different seasons and unit processes, and thus it requires continuous monitoring under various conditions to evaluate the functions. In addition, micro-bubbles helped prevent the formation of anaerobic zones in the lower part of the floating wetland. This resulted in the water circulation to form a new healthy aquatic ecosystem in the surrounding environment, which confirmed the positive influence of mFWI.