• 한국방재학회 논문집
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• 제10권4호
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• pp.89-93
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• 2010

유역의 급격한 도시화는 지체시간, 첨두유량 및 총 유출량 등 홍수 유출특성 뿐만 아니라 개발행위에 따른 토사유출특성 변화를 초래하여 배수관로내의 토사퇴적을 유발하여 도시홍수 발생 가능성 등 다양한 문제를 유발하고 있다. 본 연구에서는 도시화가 진행 중인 시험유역을 선정하여 지난 3년 동안 토지이용분포의 변화양상은 물론 강우 및 수위 자동계측기를 이용하여 연속적으로 유출수문 특성을 계측하였으며 유량-유사량 관계곡선을 유도하였다. 실측결과로부터 호우사상별 토지이용분포 변화에 따른 유출률과 첨두유출량의 변화를 정량적으로 분석하였으며 유역개발 건설과정에 따른 토사유출량의 변화특성을 정성적으로 분석하였다. 도시화가 진행될수록 합리식의 유출계수는 증가하였다. 토사의 경우 공사기간 중 유출량의 변화가 심하다는 사실과 특히, 공사기간 중 1 cms 미만의 유출을 유발하는 소규모 강우에 의한 부유사 유출은 약 10배 이상 증가한다는 사실을 확인하였다. 그러나 소류사의 경우 강우의 크기에 민감하지 않음을 확인할 수 있었다.

• 상하수도학회지
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• 제21권2호
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• pp.235-242
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• 2007

Road runoff water includes various heavy metals (zinc, Zn; lead, Pb; copper, Cu; chrome, Cr; cadmium, Cd; etc.) and pathogens (E-coli and coliform). Since these pollutants are significantly harmful to human beings and have negative impact on water streams, numerous studies have been conducted to determine the characterization of these non-point pollutants from road runoff water. However, since these non-point pollutant concentrations vary depending on road traffic, road construction, and road maintenance, measurement of pollutant loadings in different site is necessary to estimate the effect of road runoff water on drinking water source. The objective of this study was to examine the quality of road runoff water from a city bridge in Seoul, Korea. This study was conducted for two years to assess annual discharge pollution loads. In this study, five key heavy metals (Zn, Pb, Cu, Cr, and Cd) and two pathogens (E-coli and coliform) were measured at 18 different events. The pollutant load mass transported was always higher than the corresponding runoff volume for Zn, Cu, and Cd, while Pb and Cr showed similar values between the load mass transported and the corresponding runoff volume. The event mean concentrations were Zn (0.908 mg/L), Pb (0.092 mg/L), Cu (0.141 mg/L), Cr (0.023 mg/L), and Cd (0.006 mg/L). Like Zn, Cu, and Cd, E-coli and coliform values (relatively high in Summer and Fall) are higher at the beginning of each event and decrease afterwards.

• 한국농공학회지
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• 제45권4호
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• pp.78-88
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• 2003

The land use changes from non-urban areas to urban areas lead to the increased impervious areas, consequently increased direct runoff and higher peak runoff. Urban areas have also been recognized as significant sources of Nonpoint Source (NPS) pollution, while agricultural activities have been known as the primary sources of NPS pollution. Many features of the L-THIA/NPS GIS, L-THIA/NPS WWW system have been enhanced to provide easy-to-use system. The L-THIA model was applied to the Little Eagle Creek (LEC) watershed in Indiana to evaluate the accuracy of the model. The L-THIA/NPS GIS estimated yearly direct runoff values match the direct runoff separated from U.S. Geological Survey stream flow data reasonably. The $R^2$ and Nash-Sutcliffe values are 0.67 and 0.60, respectively. The L-THIA estimated runoff volume and total nitrogen loading for each land use classification in the LEC watershed were computed. The estimated runoff volume and total nitrogen loading in the LEC watershed increased by 180% and 270% for the 20 years. Urbanized areas -"Commercial", "High Density Residential", and "Low Density Residential"- of the LEC watershed made up around 68% of the 1991 total land areas, however contributed more than 92% of average annual runoff and 86% of total nitrogen loading. Therefore, it is essential to consider the impacts of land use change on hydrology and water quality in land use planning of urbanizing watershed.nning of urbanizing watershed.

• 한국농공학회지
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• 제8권1호
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• pp.1011-1034
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• 1966

This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

• 물과 미래
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• 제29권3호
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• pp.207-216
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• 1996

본 연구에서는 기존의 주택지외곽의 하천 하류부 저지대를 대규모로 개발하여 택지를 조성하는 사업이 진행되고 있는 인천시 부평구 관내의 동수천유역을 대상으로 장차 하류부 전체에 대해 택지개발이 계획되고 있는 점을 고려하여, 이 유역의 개발로 인한 총유출량과 첨두유량 및 첨두도달시간의 변화정도를 도시화단계별, 재현기간별, 강우분포형태별로 살펴보았다. ILLUDAS 모형을 사용하여 유출해석을 하고 도시화단계를 3가지 단계로 나누고 7가지 재현기간에 따라 설계강유량을 Huff의 4분위법으로 분포시켜 유출해석한 결과, 강우분포형별 첨두유량의 크기는 Huff 4 분포, Huff 2 분포, Huff 3 분포, Huff 1 분포형순으로 나타났다. 강우분포형별로 도시화단계 70%를 기준으로 80, 90%에 따른 총유출량의 평균증가율은 3.5, 5.5% 였고, 첨두유량의 평균증가율은 4. 2%, 8.8%로 나타났으며, 첨두도달시간의 감소율은 4.4, 10.1%로 나타났다. 또한 각 재현기간별로는 도시화단계 80, 90%에 의한 총유출량의 평균증가율은 3.0, 5.4%였고, 첨두유량의 평균증가율은 3.9%, 8.0%로 나타났다.

• 대한환경공학회지
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• 제33권1호
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• pp.1-8
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• 2011

본 연구는 도시환경개선계획의 일환으로서 강우유출수 제어설비의 크기 결정과 관련된 복합 설계기법을 제안하고 있다. 제안된 복합설계기법의 목적은 도시 개발이전의 수문순환상태를 복원시키는 것에 있다. 먼저, 연속적인 강우기록으로부터 개개의 강우사상을 분리하기 위해 IETD를 결정한다. 그 다음에 NRCS-CN 방법을 적용하여 모든 강우사상에 대한 직접유출량과 침투량을 산정한다. 직접유출량과 침투량의 장기간 통계치는 개발이전, 개발이후, 개발이후 유수지 설계, 그리고 개발이후 제안된 복합설계의 경우에 대하여 각각 분석된다. 개발이전의 직접유출량과 침투량을 재현하기 위해서 유전자 알고리즘을 적용하여 유수지 및 침투기반 저류지의 크기가 산정된다. 제안된 복합설계기법은 자연 상태의 직접유출량과 침투량의 통계치를 재현하는데 매우 효과적인 것이 보여진다.

• 한국농공학회지
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• 제39권2호
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• pp.134-142
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• 1997

This study was performed to evaluate the drain runoff characteristics from one paddy field, and to provide the basic data required for the determination of flood discharge and unit drainage water for drainage improvement and farmland consolidation. For this purpose, under the assumption that drain discharge from paddy field was similar to outflow of reservoir, runoff model based on storage equation was applied to the experimental field, and simulated results were compared to the measured discharge at weir point. To estimate effective storage volume of paddy field with water depth, 4 regression formula were examined such as linear, exponential, power, and combined. From the observed runoff characteristics, it was shown to be 3.3~16.3${\ell}$/sec in weir discharge, 57.2~98% in runoff ratio, and relative error of simulated result was 3.0~39.4%, 8.5 ~56.0 % for peak flow and runoff ratio, respectively. Curve number by SCS method was calculated as mean value of 96.4 using measured rainfall and runoff data, it was considered relatively high because paddy field has generally flooding depth contrary to the upland watershed area.

• 한국농공학회논문집
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• 제46권3호
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• pp.43-54
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• 2004

For a given watershed that consists of urbanized areas, it was essential to predict how the runoff characteristics, such as runoff peak and volume, and travel time, change with time far planning and designing various kinds of hydraulic facilities with given recurrence interval. In this study, Mushim stream watershed was simulated using HEC-HMS model to get runoff characteristics of an urbanization basin. The results was showed that runoff was increased $1794.20{\sim}2104.65\;m^{3}/s$> and $1751.90{\sim}1961.30\;m^{3}/s$ according to the increased of rainfall and CN value recurrence interval in years. Observed storm was increased $497.91{\sim}581.71\;m^{3}/s$ and $506.57{\sim}537.01\;m^{3}/s$ for increased of CN value and impervious area. This paper is also possible to evaluate the effect of urbanization quantitatively.

• Environmental Engineering Research
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• 제14권4호
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• pp.262-269
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• 2009

This study examined the separation characteristics of particles in the rainfall runoff from paved roads using a ${\varphi}7.5$ cm hydrocyclone. The volume fraction and total suspended solids concentrations in the overflow and underflow from the hydrocyclone, as well as the separation efficiency were determined. The results indicated that the overflow volume increased with increasing operational pressure, but decreased with decreasing ratio of underflow outlet to inlet sizes ($D_u/D_i$), while the underflow to overflow volumes showed contrary behavior. The total suspended solid (TSS) concentration ratio between the overflow and inflow ($TSS_{over/in}$) decreased as a function of the operational pressure, while the corresponding ratio of underflow to inflow ($TSS_{under/in}$) increased. There was no visible difference in the $TSS_{over/in}$ with increasing $D_u/D_i$ ratio, but the $TSS_{under/in}$ decreased sharply. The particle removal efficiency was mainly affected by the particle size.

• 한국방재학회 논문집
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• 제4권4호
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• pp.27-34
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• 2004

본 연구에서는 인공함양법을 적용한 유역에서의 유출특성 변화를 알아보기 위하여 실험유역을 설정하고 각각의 유역에 대하여 실제강우 실험과 강우모의 실험을 실시를 통하여 유출-침투특성을 분석하였다. 실강 우시 유출-침투특성 분석을 위해 2004년 7월 11일${\sim}$7월 17일 사이에 내린 4개의 강우사상에 대하여 분석을 실시한 결과 인공함양유역에서 유출이 발생하는 경우의 유출율 평균은 약 10.61%, 침투율 평균은 89.39%로 파악되어 유출되는 유량의 대부분이 인공함양법 적용에 의해서 침투가 가능한 것으로 나타났으며, 강우모의 실험에서는 강우강도의 변화와 상관없이 1시간의 지속시간을 가지는 60mm/hr ${\sim}$ 100mm/hr 구간에서 유출되는 유량 없이 전량이 침투되는 것으로 나타났다. 그러나, 인공함양시설을 설치한 경우라도 장기간 강우 발생시 주위의 지하수 변화에 의해서 유출이 발생할 수 있으므로 주변의 지하수위에 대한 지속적인 관찰이 요망된다.