현재 국내에서는 매년 평균 100여개의 교량이 붕괴되거나 심각한 피해를 입고 있다. 이들의 대부분은 홍수시 기초지반이 유실됨으로써 발생되며 다라서 세굴에 의한 피해를 줄이기 위하여는 우선 이에 대한 기초적 연구와 함께 교량설계시 예상되는 세굴깊이를 정확히 산정하고 이를 설계에 합리적으로 반영시키는 것이 필요하다. 그러나 세굴이 발생되는 물리적 현상은 많은 인자들이 서로 복잡하게 연계되어 해석하기에 쉽지 않으며 실측된 자료 또한 찾아보기 힘들다. 본 연구

본 연구에서는 남부 지방 농촌 소하천 제방 지역에 분포하는 죽림의 제방 보강역할을 파악하기 위해서 경남 진주시에 위치한 소하천 제방에 분포하는 죽림(분죽)과 잔디의 지중 뿌리 밀도 및 각 제방 토양의 관입 저항을 측정하였다. 연구 결과는 다음과 같다. 1. 대나무의 경우 토양 깊이가 깊어질수록 뿌리 분포량이 증가하는 경향을 보이는 반면 잔디는 감소하는 경향을 보여 지중 20-30cm 구간에서 가장 높고 지표면(0-l0cm)에서 가장 낮게 나타났다. 반면에, 잔디는 지표면(0-10cm)에서 가장 높은 뿌리 밀도를 보였으며, 지중 20-30cm 구간에서 가장 낮은 뿌리 밀도를 보였다. 또한, 지중 30cm까지의 전체 뿌리 분포량은 대나무가 잔디의 약 2.5배에 이른다. 죽근의 경우 지중 50cm 이상까지 분포함을 고려할 때, 실제로는 이보다 차이가 많을 것으로 예상된다. 2. 시료채취를 위한 관 삽입 시 소요되는 타격수는 지중 뿌리의 밀도에 따라서 현격하게 차이가 나는데 죽근의 관입 저항치(평균 21회)가 잔디(평균 8회)의 3배 정도인 것으로 나타났다.

The purpose of this study is to find the bi-polar adjectives for rural stream landscape evaluation by the semantic differential scale and to suggest the major determinants of visual preference in rural stream landscapes. For this, the bi-polar adjectives for rural stream landscape evaluation was found by the method of the reliability test, and the spatial image was analyzed by the factor analysis. The level of visual preference was measured by slide simulation test, and these data were analyzed by the multiple regression. The major findings of this study can be summarized as follows : 1) Of the bi-polar adjectives expressing psychological and physical characteristics, the hi-polar adjectives which demonstrated reliability and consistency run as follows : Bi-polar adjectives expressing psychological characteristics : 'calm-bustling', 'unfamiliar-familiar', 'still-active','depressing-brisk', 'discomfortable-comfortable', 'suppressed-free', 'lifeless-living', 'quiet-noisy', 'unpleasant-pleasant'. Bi-polar adjectives expressing physical characteristics : 'artificial-natural', 'narrow-wide', 'rocky-not rocky', 'desolate-fertile', 'dirty-clean', 'enclosed-open', 'flat-steep', 'not gravelly-gravelly', 'thicketed-not thicketed', 'not weedy-weedy'. 2) Two factors, the harmony and the movement, were derived from the factor analysis for the psychological variables. Three factors, the naturalness, the rock, and the vegetation, were derived from the factor analysis for the physical variables. 3) Rural stream landscape types were classified into four types by the multi-dimensional scaling method. Type III, IV obtained higher rank of visual preference and type I, II obtained lower. 4) For all types, the factors determining the level of visual preference were found to be the harmony, the naturalness, and the vegetation. The visual preference determinants of rural stream landscape need to be considered in improving or restoring the rural stream landscapes.

In order to manage the water quality from the flowing streams in Cheju Island, the characteristics of water quality was investigated from August, 1996 to May, 1997 and the pollutant loadings for future were estimated from the watershed at each stream. Comparing the mean concentrations of each water quality with the criterion of water quality in river, it was under I class except for Changgo Stream, for DO, under I class at the whole station for SS and under Ⅱ class for BOD. As the pollutant loadings at each stream in 2020 is compared with those in 1996, the estimated results are as follows : 1) for BOD, 59% at Donghong Stream, 24% at Yeonoe Stream, 44% at Ohngpo Stream and 57% at Changgo Stream. 2) for T-N, 91% at Donghong Stream, 76% at Yeonoe Stream, 63% at Ohngpo Stream and 89% at Changgo Stream. 3) for T-P, 69% at Donghong Stream, 42% at Yeonoe Stream, 45% at Ohngpo Stream and 73% at Changgo Stream The point source loadings discharged through combined sewer could be treated at sewage treatment plant. However, the expected slow decreasing rate of BOD, T-N, and T-P loadings is due to the part of untreated nonpoint source loadings. Nonpoint source loading overflow typically occurs when the flow of stormwater combined with sewage exceeds the capacity of the interceptor sewers. Since most of the sewers used in Cheju Island are the combined sewers, the combined overflow sewage is bypassed into the receiving water area after a rainstorm. Therefore, a means to control nonpoint source loadings should be considered for the river and marine water quality management.

In this study, the Dilution Method is used to measure river discharge through the hydraulic model test. the dilution method is divided into Constant-Rate-Injection Method and Slug-Injection Method in the river discharge measurement techniques. When the dilution method is applied in the hydraulic model flume, it is analyzied that the estimated error of constant-rate-injection method is less than that of the slug-injection method, and the result shows that floodflow analysis is more efficient than lowflow analysis as compared observed discharge with calculated discharge. The result of statistical error analysis shows that the constant-rate-injection method is appropriate technique for the measurement of the river discharge. Therefore, the dilution method among the river discharge measurement techniques can be applied for the river basin which can`t be measured with current meter or unsteady-flow regime in the urban-small drainage or hydraulic structure equipment area and can be obtained more exact results than any other discharge measurement techniques.

본 연구는 한강유역 중소하천 계획하폭 산정공식을 결정하기 위하여 216개 구간의 중소하천에서의 계획홍수량, 유역면적, 하상경사, 실제하폭을 수집한 후, 1) 최소자승법(least squares, LS), 2) 최소중간치자승법(least median squares, LMS) 및 3) 재가중최소자승법(reweighted least squares, RLS)을 이용하여 경험적인 계획 하폭 공식을 결정하였다. 한강유역에서의 기존하폭 산정공식과 비교하기 위하여 계

기존의 연구자들은 하천길이의 프랙탈 차원은 유역내 전체 하천에 대해 균일하며 그 수치도 1.09~1.13로 상당히 크게 보았다. 그렇지만 국제수문개발계획의 대표유역중 하나인 평창강수계내 이목정 소유역을 대상으로 1/50,000, 1/25,000, 1/5,000의 3개 축척 지형도를 이용하여 프랙탈 차원을 산정한 결과 하천차수별로 서로 다른 프랙탈 차원을 갖는 것을 발견하였고, 또한 전체 하천으로 보아도 기존 연구자들이 제안한 수치보다 작은 수치를 보였다

본연구에서는 Einstein과 Chien(1954)의 이론은 토대로 하여 하천의 모형연구에 적합한 이동상 모형이론을 수립하였다. 흐름의 상사 ()와 유사이동의 상사 ()의 변화에 따른 총 하상변동량의 거동을 비교함으로써 적용성을 검토하였다. 그 결과 의 값 또는 의 값이 작을 수록 총 사항변동량은 크게 발생하는 것으로 나타났다. 본 연구에서 수립된 모형이론은 각 모형이론의 제한조건을 완화한 것으로서 실험장소 또는 모형사의 제한으로 모형이론을 이상적으로

This study estimate the degree of contamination in the streamwater around the Sudokwon landfill site. It was sampled at 10 sites in Jan., Apr., Jul. and Oct., 1996. There were analyzed five kinds of toxic chemical material-CN, ABS, PCB, As, Org-P, and four kinds of heavy metal-Pb, Hg, Cd, C_r^+6. The result are 1)The COD was generally increased to compare before landfill, 2)The Org-P and PCB were not detected at all points, 3)The concentrations of Pb, C_r^+6 and As were lower than the environmental criteria values, 4)The CN, Hg and Cd were over envirommental criteria values, and so emergent regulation is needed, 5)The effects of the streamwater contamination were not only the leachate of the landfill, but also the small factories and agricultural land around the landfill.

여러 소하천으로 이루어지는 수계에서 복잡한 물수지 요소가 여러 지점에서 발생하는 하천 말단 특히 감조지역에 수자원 시설물을 설치하고자 할 때 유입량의 추정이 문제가 되며 물수지 요소의 변동에 따라 말단의 유출량이 영향을 받는다. 이러한 문제는 하천의 유입.유출요소의 정형화를 필요로하며 소유역의 일유출량 추정 모형을 필요로 한다. WWASS 모형은 일별 유입량과 펼요수량 추정 모형으로써 DIROM을 사용하고 있고 물수지 요소들을 하천의 조절점(contro

The objectives of this study is to evaluate the total runoff yield, peak flow and peak flow travel time depending on the urbanization, return period and rainfall patterns at the downstream of Manchon urban watershed in TaeGu City. SWMM(Storm Water Management Model) is used for runoff analysis based on 5 different steps of urbanization and 4 different types of Huff`s quartile according to 8 return periods. It is analyzed that the order of total runoff yield according to rainfall patterns is Huff`s 4, Huff`s 2. Huff`s 3 and Huff`s 1 quartile, that of peak flow magnitude is Huff`s 2, Huff`s 1, Huffs`4 and Huff`s 3 quartile at present development ratio. under the 60, 70, 80 and 90% of urbanization to the 50% of urbanization by means of the rainfall patterns, the mean increasing ratio of total runoff yield for each case is 4.55, 11.43, 16.07 and 20.02%, that of peak flow is 5.82, 13.61, 17.15 and 18.83%, the mean decreasing ratio of peak flow travel time is 0.00, 2.44, 5.07, and 6.26%, the mean increasing ratio of runoff depth is 4.51, 11.42, 16.02 and 20.05%, respectively. the mean increasing ratio of total runoff yield by means of each return period & Huff`s 3 quartile is 4.86, 12.11, 17.14 and 21.56%, that of peak flow is 5.89, 13.97, 17.82 and 19.71%. Therefore, as the result of this study, it can be used for principal data as to storm sewage treatment and flood damage protection planning in urban small watershed.

This study was carried out to develop the stream water quality model for the intaking station of Kongju waterworks in the Keum River system. The monthly water quality(total nitrogen and total phosphorus) with periodicity and trend were forecasted by multiplicative ARIMA models and then the applicability of the models was tested based on 7 years of the historical monthly water quality data at Kongju intaking site. The parameter estimation was made with the monthly observed data. The last one year data was used to compare the forecasted water quality by ARIMA model with the observed one. The models are ARIMA(2,0,0)×(0,1,1)_12 for total nitrogen, ARIMA(0,1,1)×(0,1,1)_12 for total phosphorus. The forecasting results showed a good agreement with the observed data. It is implying the applicability of multiplicative ARIMA model for forecasting monthly water quality at the Kongju site.

기존의 DWOPER 모형에 대해서도 불확실도 기법을 이용한 홍수범람 해석을 위해 DWOPER-LEV 모형을 개발하였고, 하천의 홍수범람에 따른 제방의 월류위험도와 가능 범람범위를 예측할 수 있도록 하엿다. 본 연구에서는 홍수추적에 있어서의 하도단면의 기하형상과 수리저항계수에 기인한 불확실도의 영향을 검토하기 위해 Monte-Carlo 기법을 적용하였다. 개발된 모형은 남한강 유역의 실제 제방붕괴로 인한 홍수범람에 적용하여 제방의 월류위험도와 제내지에서의

DWOPER 모형에 제방월류 및 붕괴에 따른 홍수해석, 제내지에서의 범람 해석등을 처리할 수 있도록 프로그램을 대폭적으로 개선, 보강한 모형을 개발하여 Arc/Info와 연계하여 처리할 수 있는 홍수범람해석시스템 FIAS(Flood Inundation Analysis System)를 구축하여 이를 남한강의 제방월류 및 붕괴에 대해서 적용하였다. 본 모형을 1995년 8월 23~27일에 남한강의 제방의 월류로 인해 발생한 범람홍수에 대해 적용하였다. 홍수

In the rainfall-runoff relation, consideration of the spatial movement of storms is very important in designing a hydraulic structure or evaluating an environmental influence for land usage. Because of this reason, this study has suggested the finite element model which consider the spatial movement of a stome and it was applied on a small river basin(Wi stream basin). In the application of the model the basin was treated as a pivot point and the storms are simulated with movement in each directions. As a result, it shows that the storms moving from north to south have bigger peak discharge and faster peak time than the storms moving in other directions. So these characteristics have to be considered in the designation of a hydraulic structure or evaluation of an environmental influence.

The purpose of this study was to investigate the pollutions of water qualities in 30 water samples from Nakdong River, Western Nakdong River, and Suyoung Stream. COD, BOD, T-N and negative ions(F-, Cl- NO3-, SO42-) of water samples were analyzed and the correlationships between water qualities were examined. The mean concentrations of COD(20.26ppm), BOD(25.36ppm), and T-N(18.05ppm) were the highest in the water sample of Suyoung Stream among the three streams and those of F-(0.25ppm), Cl-(27.70ppm), and SO2-(37.66ppm) in Western Nakdong River, that of NO_3,(10.81ppm) in Nakdong River. The water quality of Suyoung Stream was the worst among the three streams in Pusan area. The correlationships between water qualities were as follows ; BOD and COD showed very high correlationship(correlation coefficient, r=0.97), SO42- and NO3- did high one(0.75), and NO3- and COD, BOD did relatively high ones(0.56 and 0.48, respectively).

During the spring and fall of 1994 and winter of 1995, the exposure time of periphyton biomass on the artificial substrata at 10 headwater streams in the southeastern Korea was evaluated in 7-14 day interval. In the streams with low periphyton biomass (chl a: 2-4 ㎎/㎡) in natural rocks, biomass of artificial substrata (unglazed the: 3.7 × 9.5 × 2 ㎝) exceeded that of the natural rocks after 28 days, while sites with high biomass (chl. a: 20-60 ㎎/㎡) in natural rocks showed slower biomass accumulation after 40 days. Due to the high light input and temperature in a partially shaded mountain stream, development of periphyton biomass in spring occurred faster than that of winter. In general, development of periphyton biomass placed on artificial substrata took 4-5 weeks in spring and at least 6 weeks in winter to reach the natural level.