• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.35-35
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• 2021

최근 우리나라는 기후변화로 인한 이상기후 현상으로 호우 및 홍수 등에 의한 수재해를 예방하기 위한 설계빈도 적용방안 개발이 필요하다. 과거 지방하천의 일률적인 설계빈도의 적용 및 간접·주관적인 하천의 중요도와 지역특성에 대한 등급의 결정은 하천사업의 효율적 관리와 수행에 있어서 저해요소로 작용되어 왔다. 또한, 미래 기후변화 시나리오에 따라 하천의 중요도 및 계획 규모가 적절히 적용되어야 한다. 본 연구는 충청남도의 492개 지방하천에 대하여 유역특성(유역면적, 형상계수), 하천특성(하도경사, 수계 및 하천차수, 배수영향 구간), 이상강우 특성(이상강우 발생빈도, 시가화 침수면적)에 대한 현재 설계빈도에 대한 적절성을 평가하였다. 설계빈도에 대한 정량적 추정은 베이즈 이론을 활용하여 가중치를 산정한 후 최적분포형을 선정하였다. 최적분포형의 중앙값을 일반적인 지방하천의 설계빈도인 80년 빈도로 설정하고 상·하위 0.5%가 각각 100년, 50년 빈도로 가정하여 492개 지방하천을 평가하였다. 이상강우의 발생빈도와 시가화 침수면적에 따라 하천의 설계빈도가 높게 산정되는 것으로 분석되었다. 미래 기후변화 시나리오를 적용할 경우 현재 설계빈도(설계수명)에 대한 시나리오별 미래 재현기간을 산정하여 미래 설계빈도에 대한 위험도를 평가하였다. 13개 기후변화 시나리오의 대표농도경로 4.5와 8.5를 분석한 결과, 평균 3.2%, 12.8%의 위험도가 증가하는 것으로 분석되었다. 본 연구결과는 객관적인 지방하천의 적정 설계빈도 결정방안을 제시하였으며, 미래 계획홍수량 증가로 인하여 효율적인 토지이용이 제한될 것으로 예상됨에 따라 하천사업의 예산절감 및 우선순위 결정 등에 활용 가능할 것으로 판단된다.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.52-56
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• 1992

1. Application of N.P.K compound fertilizer increased N.P.K contents in soils and application of peat and Miwon organic fertilizer showed the trend of increasing N contents in soils also. 2. N, Ca and Mg contents in radish leaves(top) were higher than in radish(bottom) but P content was revered. And application of N.P.K compound fertilizer always incresased N content in radish plants regardless of any other fertilzer addition. 3. Application of N.P.K compound fertilizer increased N.P.K contents in cabbage plants more compare to no application of N.P.K compound fertilizer regardless of other fertilizer application. 4. Plant growth status and yield (fresh weight) of radish and cabbage revealed that every fertilizer application increased plant growth and yield compared to no fertilizer application, but N.P.K compound fertilizer showed higher increment compared to organic matter fertilizer application except Miwon(2 level)treatment. However, organic fertilizer application together with N.P.K compound fertilizer level recommended showed the highest in radish and cabbage yield. 5. Effects of four organic fertilizer on yields(fresh weight) of radish and cabbage were in the order of Miwon organic fertilizer ${\geq}$ Biovin organic fertilizer > Compost ${\leq}$ Peat.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.105-109
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• 2001

Poorly drained coarse textured paddy soils has harmful substances(e.g. $Fe^{2+}$, $H_2S$, organic acid etc.) due to reduction condition, and lower soil temperature during early stage of rice crop. The roots of the rice plant usually were distributed in the surface layer, and prone to lodged. To solve the problems, the study was carried out in the typical poorly drained, sandy loam textured paddy soils during 1997-1998. Coated urea and urea fertilizers were applied on the surface and whole layer mixed respectively. Yield of the surface fertilization of coated urea had increasing tendency but not significant. Advantages of this experiment was saving of about 30% of nitrogen fertilizer and top dressing labour, which would reduce possibility of water pollution.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.413-422
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• 2013

In recent, the rainfall is showing different properties in space and time but the ground rain gauge only can observe rainfall at a point. This means the ground rain gauge has the limitations in spatial and temporal resolutions to measure rainfall and so there is a need to utilize radar rainfall which can consider spatial distribution of rainfall This study tried to apply radar rainfall for runoff simulation on an urban drainage system. The study area is Guro-gu, Seoul and we divided study area into subbasins based on rain gauge network of AWS(Automatic Weather station). Then the radar rainfalls were adjusted using rainfall data of rain gauge stations the areal rainfalls were obtained. The runoffs were simulated by using XP-SWMM model in subbasins of an urban drainage system. As the results, the adjusted radar rainfalls were underestimated in the range of 60 to 95% of rain gauge rainfalls and so the simulated runoffs from the adjusted radar and gauge rainfalls also showed the differences. The runoff peak time from radar rainfall was occurred more fast than that from gauge rainfall.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.523-534
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• 2011

In this study, the particle size distribution and pollutants content of sediments collected from different sites in the coastal area of Chungnam province were analyzed. The sediment samples were collected from different parking lots near beaches, harbors, museum and bridges. The particle size distribution analysis showed that the particle is generally $106-500{\mu}m$ and the effective size $D_{10}$ ranges from 40 to $60{\mu}m$ while the $D_{50}$ and $D_{60}$ ranges from 200 to $810{\mu}m$ and 235 to $1005{\mu}m$, respectively. For particle size $D_{10}$, there was no significant difference in all sites. However, for $D_{50}$ and $D_{60}$, the range is large. Sediment analysis implicates that as the particle size decreases, the pollutant content increases. This is because smaller particles have higher specific surface area resulting to have more adsorption capacity. Particles from tires, emission gas from vehicles and dust particles belongs to smaller particles. For particle sizes less than $63{\mu}m$, the analysis showed that as the particles become coarser, the concentration of VS, $COD_{cr}$, TN, and TP is at least 2 to 14 times higher. Cu and Pb were detected in all sites and shows a higher concentration with smaller particle size. Cu concentration are almost the same for all sites but in the case of Pb, the sediments from Sinjindo has higher concentration of up to 2 to 3 times as compared to those collected from the other sites. In the Beach site as well as in the Seocheon Ocean Museum, Cd was contained only in fine particles. However, in Daechon Harbor and Sinjindo Bridge sites, Cd was detected in all the sediment particle size.

• Journal of Korea Water Resources Association
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• v.38 no.3 s.152
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• pp.213-222
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• 2005

This study is a sensitivity analysis of the parameters which affect the simulation results under various design rainfall conditions, using the SWMM model, for three selected basins in urban areas. The sensitivity of the peak flow rate is defined by $S_Q$ (=1.0 - (min. ratio of peak flow rate/max. ratio of peak flow rate)), and the rainfall conditions are classified in terms of design rainfall frequency, duration, and distribution. The simulation results show that in most conditions the parameters - the impermeable area ratio, the sewer slope, and the initial infiltration capacity - have more significant effects on the results than other parameters. As the design rainfall frequency increases, the sensitivity of the sewer slope and sewer roughness increases, while the parameters related with the surface runoff decrease. When the rainfall duration increases, the sensitivities of most parameters of surface runoff and sewer flow decrease. Also, at the 1st quarterly Huff rainfall distribution condition, the impermeable area ratio has high sensitivity, but at the 4th quarterly condition the parameters related with sewer flow show higher sensitivities. These tendencies can be explained by considering the procedure for computing the effective rainfall and kinematic wave on the surface and sewer flow.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.15-22
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• 2013

5 each permeable and impermeable debris dams were selected to analyze the characteristics of dredging and sedimentation according to facility type in Inje, Gangwon. Field tests for the ground water table and sedimentation characteristics of the selected dams were performed. Furthermore, data of the dredging amount, storage capacity, and drainage area were analyzed for the 51 more debris control facilities. From the results of field tests, it was found that the storage capacity of impermeable debris dam could be not enough when the large debris flow is produced since sediments are accumulated even if large debris flow was not occurred. Drainage can be a problem since the ground water table of impermeable debris dam was reached to the surface of ground. However, it was found that the ground saturation should not occur at heavy rain since ground water table of permeable debris dam was located in lower part of buttress. Furthermore, from the analysis results of relation among the dredging amount, basin area, and capacity of debris control facility, it was found that size of debris control facility was not reflected by the basin area. Effective planning and construction should be accomplished for the future since the real sedimentation amount was not significant even though large debris dams were constructed.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.252-252
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• 2020

대하천 주변 광역상수도 공급지역은 가뭄 발생시에도 안정적으로 물이용이 가능하나, 중소하천을 수원으로 하는 하천의 상류지역은 가뭄시 물공급 안정성이 취약하다. 따라서 중소하천을 대상으로 가뭄시 물 공급시설의 효율적 운영, 물부족 위험도 평가, 가용 수자원의 최적이용 등 종합적인 대책 마련을 위해서는 신뢰성 높은 수문량(하천유출량 및 수자원가용량) 예측이 필요하다. 기존의 가뭄시 하천유출량 예측정확도 평가는 통계적 회귀분석을 통한 가뭄지수 기반의 가뭄상황의 예측에 치중하여 불확실성이 크며 국내 유역의 복잡한 물이용체계를 고려하지 않아 시·공간적인 규모에 따라 상이한 결과를 나타내며 실측자료 기반의 하천유출량과 비교하면 정확도가 대부분 60% 이하로 나타난다(이상은 등, 2015). 본 연구에서는 상세 물이용체계를 고려한 정도높은 수자원가용량의 평가를 위하여 한강권역 내의 한탄강댐 상류 유역을 테스트베드로 선정하였다. 한탄강댐 상류유역은 다수의 복잡한 농업용 수리시설 운영에 따른 수자원가용량 예측정확도가 매우 낮은 지역으로 본 연구를 통해 정도 높은 수자원가용량 예측정확도를 확보하기에 적정한 유역이라 판단하였다. 수자원가용량을 평가하기 위한 모형은 한국건설기술연구원에서 개발된 CAT3.1(Catchment hydrologic cycle Assessment Tool 3.1)을 이용하였다. CAT 3.1은 중소하천 유역내의 인위적인 물이용체계(광역급수, 재이용, 지하수 취수, 하천수 취·배수 등)를 반영한 수문량(하천유출량 및 수자원가용량) 평가 및 예측이 가능한 모형으로 기존 개념적 매개변수 기반의 집중형 수문모형과 물리적 매개변수 기반의 분포형 수문모형의 장점을 최대한 집약하여 개발되었다. 한탄강댐 상류유역의 물리적 매개변수는 최대한 기 구축된 GIS 자료를 활용하여 추출하였다. 토지이용현황은 산림과 농업지역이 대부분을 차지하여 농업용수 공급이 대부분인 물이용체계를 가지고 있다. 따라서 한국농어촌공사에서 관리하는 11개 농업용 저수지에 대한 취수현황 및 제원, 국가지하수센터의 유역내 지하수사용량, 하폐수처리량을 기본 입력 자료로 사용하였다. 특히 농업용 저수지의 경우에는 저수지출구점을 기준으로 저수지 상류유역 및 한국농어촌공사에서 기 구축된 관개면적 공간자료를 기본으로 수혜구역을 세분화하여 모형을 적용하였다.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.25-38
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• 2007

A grid-based urban surface runoff model for simulating the temporal variation and spatial distribution of overland flow in a drainage area was developed. The process of routing of overland flow is modeled by the nonlinear storage equation which is composed of the continuity equation and the Manning's equation. For model operation, the drainage area is divided into grid areas, and spatially distributed topographical and hydrological information for model inputs is provided. Then overland flow is routed for each of the discretized cells of the area. In order to test the applicability of this model, temporal variations and spatial distributions of flow depth and overland flow was simulated in a fictitious and a real urbanized Kunja drainage area. Results indicate that the model can simulate reasonably well the urban runoff hydrograph.

• Journal of Soil and Groundwater Environment
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• v.10 no.6
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• pp.32-44
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• 2005

314 pumping test data of the National Groundwater Monitoring Wells (NGMWs) are analyzed to present statistical properties of fractured-rock and alluvial aquifers of Korea such as distribution of hydraulic conductivity, empirical relations between transmissivity and specific capacity, and time-drawdown patterns of pumping and recovery test. The mean hydraulic conductivity of alluvial aquifers (1.26 m/day) is 17 times greater than that of fractured-rock aquifers (0.076 m/day). Hydraulic conductivity of fracture-rock aquifers ranges in value over 4 orders of magnitude which coincide with representative values of fractured crystalline rocks and shows distinctive differences among rock types with the lowest values for metamorphic rocks and the highest values for sedimentary rocks. In consideration of the estimated transmissivity with some simplifying assumptions, it Is likely that $32\%$ of groundwater flow for NGMWs would occur through fractured-rock aquifers and $68\%$ through alluvial aquifers. Based on 314 pairs of data, empirical relations between transmissivity and specific capacity are presented for both fractured-rock and alluvial aquifers. Depending on time-drawdown patterns during pumping and recovery test, NGMWs are classified into $4\~5$ types. Most of NCMWs $(83.7\%)$ exhibit the recharge boundary type, which call be attributed to sources of water supply such as streams adjacent to the pumping well, the vertical groundwater flux between fractured-rock and the alluvial aquifers, and the delayed yield associated with gravity drainage occurring in unconfined aquifers.