상류 수위관측소 자료를 활용한 하류 지점 수위 예측

홍원표,송창근,Hong, Won Pyo,Song, Chang Geun 한국안전학회 2020 한국안전학회지 Vol.35 No.2

Recently, the overseas construction market has been actively promoted for about 10 years, and overseas dam construction has been continuously performed. For the economic and safe construction of the dam, it is important to prepare the main dam construction plan considering the design frequency of the diversion tunnel and the cofferdam. In this respect, the prediction of river level during the rainy season is significant. Since most of the overseas dam construction sites are located in areas with poor infrastructure, the most efficient and economic method to predict the water level in dam construction is to use the upstream water level. In this study, a linear regression model, which is one of the simplest statistical methods, was proposed and examined to predict the downstream level from the upstream level. The Pyeongchang River basin, which has the characteristics of the upper stream (mountain stream), was selected as the target site and the observed water level in Pyeongchang and Panwoon gaging station were used. A regression equation was developed using the water level data set from August 22th to 27th, 2017, and its applicability was tested using the water level data set from August 28th to September 1st, 2018. The dependent variable was selected as the "level difference between two stations," and the independent variable was selected as "the level of water level in Pyeongchang station two hours ago" and the "water level change rate in Pyeongchang station (m/hr)". In addition, the accuracy of the developed equation was checked by using the regression statistics of Root Mean Square Error (RMSE), Adjusted Coefficient of Determination (ACD), and Nach Sutcliffe efficiency Coefficient (NSEC). As a result, the statistical value of the linear regression model was very high, so the downstream water level prediction using the upstream water level was examined in a highly reliable way. In addition, the results of the application of the water level change rate (m/hr) to the regression equation show that although the increase of the statistical value is not large, it is effective to reduce the water level error in the rapid level rise section. Accordingly, this is a significant advantage in estimating the evacuation water level during main dam construction to secure safety in construction site.

토성별 지하수위가 밀, 보리의 품질에 미치는 영향

이홍석,구자환 韓國作物學會 1995 Korean journal of crop science Vol.40 No.3

본 연구는 토성별 지하수위가 밀, 보리의 생산물 종실의 품질 및 발아와 효소활성에 미치는 영향 등을 추구함으로서 적정지하수위와 지하수위에 따른 피해 정도를 구명 평가하고자 실시하였다. 올보리와 그루밀을 공시하여 1992년 10월 ~ 1993년 6월에 걸쳐 대형포트(550 liter) 시험을 수행하였다. 토성을 식양토와 사양토로 조성하여 전 생육기에 걸쳐 지하수위가 20, 30, 40, 50, 70cm가 되도록 조절하고 비가림 재배를 실시하였는데 그 결과를 요약하면 다음과 같다. 1. 정립비율과 종보비중은 토성과 지하수위에 따른 영향이 일정하지 않았으며 1,000립중은 보리와 밀 모두 지하수위가 낮아짐에 따라 증가하였고 토성에 따른 차이는 미미하였다. 2. 조단백 함량은 보리와 밀 모두 지하수위가 높아질수록 많아졌으며 특히 밀에서 뚜렷하게 나타났다. 토성에 따른 조단백 함량의 변화는 지하수위에 따른 영향보다 적었으며 사양토에서의 것이 식양토의 것보다 높은 경향이었으나 그 차이는 적었다. 3. 조지방 함량은 보리와 밀 모두 지하수위가 높아질수록 낮아졌으며 사양토에서의 조지방 함량이 높은 경향으로 나타났다. 4. 회분 함량은 보리와 밀 모두 지하수위가 높아질수록 낮아졌으며 특히 사양토에서 그 경향이 뚜렷하였다. 5. 밀의 제분율은 토성에 따른 차이는 없었으며 지하수위 20cm에서 종실 제분율이 65% 정도로 나타났고 지하수위 40cm 이하에서 제분율이 67% 이상으로 나타났다. 6. 20℃ 에서 3일 이내의 발아율에서 보면 보리와 밀 모두 모든 처리에서 95% 이상의 발아율을 보였으며 토성에 관계없이 지하수위 20cm에서 가장 낮은 발아율을 보였고 지하수위가 낮아질수록 발아율도 높아졌다. 7. 보리에서 24시간 이내의 발아율에서는 일정한 경향을 나타내지 않았으나 48시간 이내의 발아율에서는 사양토의 지하수위 20cm 처리를 제외하고는 89% 이상의 발아율로 나타나 48시간 이내에 대부분이 발아하는 발아세를 보였다. 8. 보리 맥아에서의 당화력(diastic power)은 지하수위 20cm 처리구에서 가장 낮게 나타났고 지하수위 30cm 이하 처리에서의 당화력의 차이는 현저하지 않았으며 토성에 따른 맥아 당화력의 차이는 나타나지 않았다. This experiment was performed to characterize the optimum water table level for the grain quality, seed germination and diastic power of barley(var. Olbori) and wheat(var. Grumil). Olbori and Grumil grew in the 550 liter plastic pot that filled with silt loam or sandy loam. During the whole growth period, the underground water level adjusted to be 20, 30, 40, 50 and 70cm. Filled grain ratio and specific gravity were not affected by soil texture and water table. Low level of water table caused the increase of 1,000 grain weight in wheat and barley, but soil texture didn't. Crude protein content tended to be high as the water table level was high, especially in wheat. Change in crude protein content was affected by underground water level more than soil texture. And the affection was slightly higher in sandy loam than silt loam, but the difference was small. The higher level of water table led to the lower crude lipid content in barley and wheat grain. Crude lipid content of both wheat and barley grain grown in sandy loam was higher than those grown in silt loam. As the water table level down, the ash content of barley and wheat grain tend to increase, especially in sandy loam. Wheat flour yield was not affected by soil texture. It was about 65% at 20cm of water level and above 67% at 40cm water level. The seed germination of wheat and barley was more than 95% when the seeds were placed at 20~circC for three days. Regardless of soil texture, the lowest germination was seen at 20cm of water table level. And the seed germination rate increased as the underground water level became low. Above 89% of barley grains were germinated within 48 hours except 20cm level of water table in sandy loam. Diastic power of germinated barley was the lowest at 20cm of water table level, and it was almost unchanged below 30cm of water table level. And also it was not affected by soil texture.

Landslide Analysis of River Bank Affected by Water Level Fluctuation Ⅱ

Kim You-Seong(김유성),Wang Yu-Mei(왕유메이),Choi Jae-Seon(최재선) 한국토목섬유학회 2010 한국지반신소재학회 논문집 Vol.9 No.3

저수지의 수위변화는 저수지 주변 강기슭 사면파괴의 주요 요인이다. 중국의 삼협댐 저수위는 홍수량 조절을 위해 145m와 175m사이에서 변화한다. 삼협댐 저수위의 정상적 운영상태에서 저수위 변동속도는 0.67m~3.0m의 범위에 있다. 마지아고 사면은 자시강의 2.1㎞ 상류 좌측기슭에 위치한다. 자시강은 삼협지역내에 있는 양츠강의 지류이다. 2003년 저수위가 95m에서 135m로 상승한 직후, 마지아고 사면의 후면부에서 길이 20m, 폭 3~10의 균열이 발생하였다. 지금은 균열 보수 후 특별한 징후는 보이지 않고는 있으나, 이 큰 균열은 마지아고 사면의 산사태 가능성을 암시하고 있었다. 이 연구에서는 침투해석에서 얻어진 간극수압을 저수위 변동에 따른 안전율 변화를 평가하기 위해 사용되었다. 안전율 평가는 한계평형해석에 의한 사면안정해석에 의해 수행되었다. 한계평형해석에서 전단강도에 미치는 부의 간극수압 효과는 불포화 흙에 대한 프레드런드의 전단강도식을 사용하여 고려하였다. 연구결과 강기슭사면의 안전율은 저수위의 상승, 하강에 따라 감소와 증가의 경향을 보이나, 가장 위험한 상태는 저수위가 최대높이를 장기간 유지할 때인 것으로 나타났다. The change of water level in reservoirs is an important factor causing failure of bank slopes, i.e. landslide. The water level of Three Gorges reservoir in China fluctuate between 145 m and 175 m, as a matter of flood control. During its normal operational state, the rate of water level fluctuation is supposed to range from 0.67 m/d to 3.0 m/d. Majiagou slope is located on the left bank of Zhaxi River, 2.1 ㎞ up from the outlet. Zhaxi River is a tributary of the Yangtze River within the Three Gorges area, of which the water level changes with the reservoir. At the back of Majiagou slope, a 20 m long and 3~10 ㎝ wide fissure developed just after the reservoir water level rose from 95 m to 135 m in 2003. This big fissure was a full suggestion of potential failure of this slope. In this study, the pore water pressure files obtained from seepage analysis were used to evaluate the change in factor of safety (FS) with reservoir water level. Slope stability analyses then were carried out, with fully specified slip surface and limit equilibrium method. In the limit equilibrium analysis, the contribution of negative pore water pressure to shear strength was considered by the use of Fredlund’s shear strength equation for unsaturated soils. On the base of the analyses, the change of FS with reservoir water level was interpreted in detail. It was found that FS against bank slopes decreases with the rise of the reservoir water level and increases with the drawdown of the reservoir water level. The most dangerous state was when the reservoir water level stays at the highest for a long time.

Landslide Analysis of River Bank Affected by Water Level Fluctuation I

김유성,왕 유메이 한국지반신소재학회 2010 한국지반신소재학회 논문집 Vol.9 No.3

The change of water level in reservoirs is an important factor causing failure of bank slopes, i.e. landslide. The water level of Three Gorges reservoir in China fluctuate between 145 m and 175 m, as a matter of flood control. During its normal operational state, the rate of water level fluctuation is supposed to range from 0.67 m/d to 3.0 m/d. Majiagou slope is located on the left bank of Zhaxi River, 2.1 km up from the outlet. Zhaxi River is a tributary of the Yangtze River within the Three Gorges area, of which the water level changes with the reservoir. At the back of Majiagou slope, a 20 m long and 3~10 cm wide fissure developed just after the reservoir water level rose from 95 m to 135 m in 2003. This big fissure was a full suggestion of potential failure of this slope. In this study, unsaturated-saturated seepage analyses were carried out to simulate the change of pore-water pressures in the bank slope subjected to the reservoir water level change. The obtained pore-water pressures were then used to evaluate the change in factor of safety (FS) with reservoir water level. It was found that the phreatic line showed a delayed response with respect to the change of the reservoir water level, because the seepage through soil layer was generally slower than water flows itself. During the rising and drawdown process, the phreatic lines take the shapes of concave and convex, respectively. And the fluctuation of reservoir water level just affected the front part of the bank slope, but had little influence on the back of the slope.

Landslide Analysis of River Bank Affected by Water Level Fluctuation II

김유성,왕 유메이,최재선 한국지반신소재학회 2010 한국지반신소재학회 논문집 Vol.9 No.3

The change of water level in reservoirs is an important factor causing failure of bank slopes, i.e. landslide. The water level of Three Gorges reservoir in China fluctuate between 145 m and 175 m, as a matter of flood control. During its normal operational state, the rate of water level fluctuation is supposed to range from 0.67 m/d to 3.0 m/d. Majiagou slope is located on the left bank of Zhaxi River, 2.1 km up from the outlet. Zhaxi River is a tributary of the Yangtze River within the Three Gorges area, of which the water level changes with the reservoir. At the back of Majiagou slope, a 20 m long and 3~10 cm wide fissure developed just after the reservoir water level rose from 95 m to 135 m in 2003. This big fissure was a full suggestion of potential failure of this slope. In this study, the pore water pressure files obtained from seepage analysis were used to evaluate the change in factor of safety (FS) with reservoir water level. Slope stability analyses then were carried out, with fully specified slip surface and limit equilibrium method. In the limit equilibrium analysis, the contribution of negative pore water pressure to shear strength was considered by the use of Fredlund’s shear strength equation for unsaturated soils. On the base of the analyses, the change of FS with reservoir water level was interpreted in detail. It was found that FS against bank slopes decreases with the rise of the reservoir water level and increases with the drawdown of the reservoir water level. The most dangerous state was when the reservoir water level stays at the highest for a long time.

Landslide Analysis of River Bank Affected by Water Level Fluctuation Ⅰ

Kim You-Seong(김유성),Wang Yu-Mei(왕유메이) 한국지반신소재학회 2010 한국지반신소재학회 논문집 Vol.9 No.3

저수지의 수위변화는 저수지 주변 강기슭 사면파괴의 주요 요인이다. 중국의 삼협댐 저수위는 홍수량 조절을 위해 145m와 175m사이에서 변화한다. 삼협댐 저수위의 정상적 운영상태에서 저수위 변동속도는 0.67m~3.0m의 범위에 있다. 마지아고 사면은 자시강의 2.1㎞ 상류 좌측기슭에 위치한다. 자시강은 삼협지역내에 있는 양츠강의 지류이다. 2003년 저수위가 95m에서 135m로 상승한 직후, 마지아고 사면의 후면부에서 길이 20m, 폭 3~10의 균열이 발생하였다. 지금은 균열 보수 후 특별한 징후는 보이지 않고는 있으나, 이 큰 균열은 마지아고 사면의 산사태 가능성을 암시하고 있었다. 이 연구에서는 저수위 변화와 관련하여 사면내에서 간극수압의 변화를 모의하기 위해 불포화 및 포화 침투해석이 수행되었다. 얻어진 간극수압은 저수위에 따른 안전율 변화를 평가하기 위해 사용되었다. 연구결과 침윤선은 저수위 변화보다 상당히 지연된 반응을 보였고, 저수위의 상승-하강과정에서 침윤선은 각각 요면과 철면의 형상을 나타내었다. 또한 저수위의 변동은 사면의 전면부에만 영향을 미치고 있었고 후면부에는 영향을 미치지 않았다. The change of water level in reservoirs is an important factor causing failure of bank slopes, i.e. landslide. The water level of Three Gorges reservoir in China fluctuate between 145 m and 175 m, as a matter of flood control. During its normal operational state, the rate of water level fluctuation is supposed to range from 0.67 m/d to 3.0 m/d. Majiagou slope is located on the left bank of Zhaxi River, 2.1 ㎞ up from the outlet. Zhaxi River is a tributary of the Yangtze River within the Three Gorges area, of which the water level changes with the reservoir. At the back of Majiagou slope, a 20 m long and 3~10 cm wide fissure developed just after the reservoir water level rose from 95 m to 135 m in 2003. This big fissure was a full suggestion of potential failure of this slope. In this study, unsaturated-saturated seepage analyses were carried out to simulate the change of pore-water pressures in the bank slope subjected to the reservoir water level change. The obtained pore-water pressures were then used to evaluate the change in factor of safety (FS) with reservoir water level. It was found that the phreatic line showed a delayed response with respect to the change of the reservoir water level, because the seepage through soil layer was generally slower than water flows itself. During the rising and drawdown process, the phreatic lines take the shapes of concave and convex, respectively. And the fluctuation of reservoir water level just affected the front part of the bank slope, but had little influence on the back of the slope.

물환경 서비스와 물 인프라의 지속가능성 평가 사업(Ⅷ)

한혜진,김호정,류재나,이병국,김수빈,신정우 한국환경연구원 2021 사업보고서 Vol.2021 No.-

Ⅰ. 연구의 배경 및 목적 □ 연구 배경 ○ 경제발전 과정에서 단기간에 많은 상·하수도 기반시설(인프라)이 건설되어 인프라의 노후화 도래 시기가 다가오고 있음 - 비교적 나중에 건설된 공공하수도시설도 약 31.2%가 법적 내용연수를 초과 ○ 철도, 발전시설 등에 비해 상·하수도 시설, 특히 지자체가 관리하는 시설의 유지관리 및 노후화 대비는 미흡함 □ 연구 목적 ○ 본 연구의 목적은 물환경 서비스 수준과 물 인프라 관리에 관한 데이터를 확보하여 기초지자체별로 물환경 서비스·인프라 관리의 지속가능성을 평가·분석하는 것임 - 지자체별로 물환경 서비스·인프라의 지속가능성 정보를 온라인 시스템을 통해 제공하며, 서비스에 대한 질적 수준 관리 등 앞으로의 물관리 정책 방안을 제언 Ⅱ. 물환경 서비스·인프라의 지속가능성 평가 결과 □ 지속가능성 평가 체계 ○ 2017년에 마련한 물환경 서비스·인프라의 지속가능성 평가체계에 따라 가장 최신의 가용 자료인 2019년 자료를 토대로 경제·사회·환경 부문별 지속가능성을 평가 - (경제) 재정 건전성, 서비스 비용 분담 수준 및 자산관리 정도를 평가 - (사회) 서비스 보급의 사회적 공평성, 서비스 품질의 지역 간 형평성 및 사회적 수용성을 평가 - (환경) 환경부하관리, 수생태계 연결성 및 다양성 및 물 사용량을 평가 □ 2019년 지속가능성 평가 결과 ○ 경제 부문에서는 지자체 규모가 작을수록 지속가능성이 낮게 나타남 - 군 단위 지자체는 자본수입비율, 상수도 중앙정부 지원액 비율, 상수도 지방비 비율, 하수도 부채비율 등의 지표가 낮았음 ○ 사회 부문에서 상하수도 서비스 보급 지표는 지자체의 규모가 클수록 양호했지만, 서비스 품질에 관한 지표는 노후화 시설이 많은 특·광역시에서 낮게 나타남 - 군 그룹의 소득 대비 상수도 요금 수준이 특·광역시나 시 그룹보다 높았음 ○ 환경 부문에서는 발생 원단위가 큰 축산계 오염원이 주로 농촌 지역에 분포해 있으므로 군 단위 그룹의 오염부하배출량이 특·광역시나 시 그룹보다 현저하게 높았음 - 공공하수처리율은 모든 그룹의 지자체가 전반적으로 양호한 수준이었음 □ 2015~2019년 지속가능성 평가 결과 추이 ○ 경제 부문의 지속가능성 지표는 대부분 큰 변화가 없었으며, 지자체 규모에 따라 평가 결과의 격차가 지속됨 - 상하수도 부채비율은 완만하게 감소하고 있지만 총사업비 대비 요금, 원인자부담금 등 자본수입의 비율은 상하수도와 하수도 모두 2017년을 기점으로 감소 - 낮은 요금 현실화율이 개선되지 않는 상황에서 코로나19 사태 장기화로 상하수도 요금 감면액이 늘어난다면 사업의 경영지표는 더욱 악화될 것으로 우려됨 ○ 사회 부문의 지표 중 시설 보급과 관련된 지표에서 지자체 규모에 따른 격차는 줄어들고 있지만, 상하수도 민원에 대한 지표는 악화 - 지자체 규모에 따른 급수보급률, 하수관로보급률 등 상하수도시설 지표의 격차는 줄어들고 있었지만, 취수장·정수장 등 상수도시설의 노후화율이 급속히 상승 - 상하수도 서비스 민원에 대한 지표는 특정 시기에 몇 개 지자체에서 발생한 사고에 따라 차이가 크게 나타남 ○ 환경 부문에서는 지표의 특성상 다섯 해 동안 뚜렷한 변화한 항목은 없었음 - T-P 배출부하량, BOD 공공하수처리율 그리고 하천수질 지표는 기간에 따라 크게 변화하지 않았음 - BOD 배출부하량은 연도별로 편차가 컸는데 국가승인통계에서 얻어지는 다른 지표에 비해 자료의 안정성이 부족하기 때문으로 판단됨 Ⅲ. 상수도 서비스의 질적 수준 분석 □ 상수도 서비스의 질적 수준 설문 결과 ○ 일반 국민이 체감하는 서비스의 질적 수준에 대한 설문조사 결과, 물환경 및 상·하수도 서비스의 인지도나 중요성과 비교해 서비스의 만족도는 낮은 수준이었음 ○ 응답자가 체감하는 현재의 수돗물 수질은 국내외 수질기준을 만족하는 수준보다는 높지만 수돗물 특유의 냄새가 없는 수준에는 다다르지 못함 - 앞으로는 현재보다 한 단계 높은, 수돗물 특유의 냄새가 없는 수준에서 생수처럼 맛과 냄새가 좋은 수준의 사이로 수돗물 수질이 개선되기를 기대함 ○ 대부분 응답자는 수돗물 공급이 중단되었을 때 반나절 이내에 급수가 재개되기를 희망하였음 - 사전에 예고된 단수들은 대부분 반나절 내에 급수가 재개되었으므로, 관건은 공사 중 사고나 재난·재해로 발생하는 예기치 못한 단수를 관리하는 것임 □ 상수도 서비스 개선에 대한 지불의사 분석 결과 ○ 조건부가치측정법(CVM)으로 지불의사를 분석한 결과, 수돗물 수질을 개선하는 것에는 수돗물 1m³당 273.1원, 수돗물 단수를 예방하여 공급 안정성을 높이는 것에는 1m³당 264.9원, 단수 발생 시 기대 수준만큼 급수가 신속하게 재개되는 것에는 1m³당 200.4원의 추가적인 지불의사를 보였음 - 이를 가구당 지불의사로 환산하면 수돗물 수질 개선, 수돗물 단수 예방, 단수 발생 시 신속한 급수 재개에 대해 각각 매월 3,561원, 3,454원, 2,613원을 추가로 지불하는 것에 해당함 ○ 수질 안전성과 공급 안정성 모두 상수도 서비스의 중요도 및 만족도에 대해 높게 응답한 경우에 지불의사액이 높았음 Ⅳ. 연구 성과의 확산 방안 □ 상하수도 운영 효율성 비교·분석 ○ 지속가능성 평가 데이터와 자료포락분석(data envelopment analysis) 방법을 이용하여 지자체별로 상수도 사업의 운영 효율성을 비교·분석하는 방법을 제시함 - 특·광역시를 제외한 154개 시·군의 2016~2019년 패널데이터를 이용하여 투입변수(직원 수, 영업비용)와 산출변수(급수보급률, 유수율, GIS 구축, 급수수익, 수도관 연장)를 분석하였음 - 상수도사업의 효율성은 증가하고 있지만 효율성 수준 자체는 낮았으며, 규모효율성 보다 순수기술효율성이 낮아 상수도사업의 운영 효율성이 부족한 것으로 나타남 ○ 지속가능성 지표의 시계열 자료를 이용하여 지자체별 상수도사업의 효율성 분석, 효율성이 우수한 지자체(벤치마크)의 선정, 효율성에 영향을 미치는 세부 요인 분석 등의 후속 연구를 진행할 수 있음 □ 지속가능성 평가 지표의 활용 방안 ○ 본 연구의 지속가능성 평가 지표는 물환경 서비스·인프라 수준의 중·장기적인 추세를 분석하는 데 쓸 수 있음 - 지속가능성 지표의 추이를 분석하여 현 시점에서 드러나는 물환경 서비스·인프라와 관련된 문제나 쟁점이 과거 어느 시점부터 진행되었는지를 파악할 수 있을 것임 ○ 국내에서는 국민 체감형 지표, 차세대 물관리 지표 등 국가 계획에서 검토했던 새로운 지표를 마련하는 데 본 연구 결과를 활용할 수 있음 ○ 국제적으로는 물·위생에 관한 지속가능발전목표(SDG 6) 중 국내에서 측정되지 않은 지표의 산정 방법을 개발하는 데 본 연구 결과를 활용할 수 있음 Ⅴ. 결론 및 정책 제언 ○ 2015~2019년 기간 지자체 규모에 따른 경제 부문의 지속가능성 지표의 격차가 지속되고 있음 - 시설 보급과 관련된 지표에서 지자체 규모에 따른 격차는 줄어들고 있지만, 상하수도 민원에 대한 지표는 나빠지고 있음 - 군 단위 지자체는 향후 상수도 요금의 현실화 과정에서 주민의 지불 능력(affordability) 문제를 유의해야 함 ○ 일반 시민이 생각하는 물환경 및 상·하수도 서비스의 인지도나 중요성과 비교해 시민들이 체감하는 서비스의 만족도는 낮은 수준이었음 - 수질 안전성과 공급 안정성에 대한 지불의사액은 상수도 서비스의 중요도·만족도와 상관성이 높으므로, 상수도 서비스의 중요도·만족도를 높이는 것이 중요함 ○ 다음 해에도 2020년 자료를 이용해 올해와 같은 방법으로 지속가능성 평가 지표를 산정하고 함의를 분석하는 작업을 수행할 것임 - 설문조사 데이터를 공유하는 방안을 비롯해 올해 연구에서 제안한 연구 성과 활용 방안에 대한 구체적인 방안을 마련하며, 연구 결과의 정책 활용 및 관련된 후속 연구 주제에 대한 탐색도 진행할 계획임 Ⅰ. Research Background and Objectives ○ The waterworks and sewerage structures, which have been extensively constructed since the 1970s and the 1990s, respectively, in Korea, will reach the end of their design life in the near future. The management of old and tired structures has become a significant concern in other social overhead capitals such as railroad, highway, and power plants. The aging issue is still to come in the water sector, but the water infrastructures, especially the ones managed by local governments (municipalities), are less prepared for tackling aging problems. ○ In order to bring attention to the aging water infrastructures, authors have assessed the sustainability of the water services and water infrastructures in each municipality since 2014. The assessment results are provided on the Web site (http://wwrd.kei.re.kr/) and is accessible by the public. New water policy strategies or directions such as asset management systems or customers’(residents’) experience management are also reviewed. Ⅱ. Assessment Results of the Sustainability of Water Services and Water Infrastructures □ The Framework of Sustainability Assessment ○ In 2017, a framework to assess the sustainability of water services and water infrastructures for each municipality was established. The framework includes three pillars - economic, social, and environmental sustainability. For economic sustainability, financial sustainability, cost allocation, and level of assessment management of water services and its management were evaluated. For social sustainability, the fairness of the water service supply, the equity of the service quality, and the social acceptance were assessed. Finally, the pollution loads, ecosystem connectivity and diversity, and water consumption level were evaluated for the environmental aspect. □ Sustainability of water services and water infrastructures in 2019 ○ The economic sustainability was low for the small-scale municipalities (‘Gun’). One of the reasons was that these small municipalities heavily depend on the subsidy from the national government. For social sustainability, the Metropolitan cities show the higher level of water service supply. However, the service quality in the Metropolitan cities is relatively low as they have more aged water infrastructures than small or midsize municipalities. For environmental sustainability, the pollutant loads in small municipalities are much greater than others, as the livestock farming is concentrated in rural areas. On the other hand, the domestic sewage is adequately collected, treated, and discharged to public waters in all municipality groups. □ Sustainability trends from 2015 to 2019 ○ Most economic indicators stay unchanged from 2015 to ’19년 and the sustainability gap among municipality groups held steady. It should be noted that the share of income from capital such as utility fee or connection fees has decreased since 2017. As the current utility fee cannot cover the supply cost of water and sewage service, the reduction of water and sewage fees during the COVID pandemic can further deteriorate the financial soundness of water services. ○ In social sector, the gap of service coverage between municipalities decreased over time. However, the aging rate of drinking water facilities is rapidly increasing across the municipalities. The indicators on service complaints significantly varied with municipalities as the complaints occurred in certain municipalities over certain years. ○ The environmental indicators including the pollution loads of total phosphorus, the ratio of treated sewage, and ambient water quality did not change significantly. It is worth noticing that the data of pollution loads, which were not officially published statistics but collected by in-house efforts, lacked data stability. Ⅲ. Qualitative Level of Water Supply Service □ Survey results on the level of water service ○ Compared to the respondents’ high awareness on water services and the perception of the importance of the water services, the satisfaction rate on water service was relatively low. ○ The respondents felt that tap water in Korea is safe to drink since it meets both international and domestic drinking water standards, but they still complain the distinctive taste and odor of tap water. They expect that the quality will be improved to the level where such taste and odor are not detected and tap water provides a similar experience with bottled mineral water. ○ Most respondents expect that tap water supply interruption should be solved within half a day. Since the interruption with advance notice is mostly settled within half a day, the interruption caused by unexpected disasters or accidents will be a significant matter. □ Willingness to pay for improving water supply service ○ The willingness to pay for improving water supply service, which was measured by contingent valuation method, was 273.1, 264.9, and 200.4 Korean Won (KRW) per 1 ㎥ of tap water for improving the safety level, preventing the service interruption, and reducing the service interruption intervals, respectively. Considering the average family size and household water consumption, those amounts are equivalent to 3,561, 3,454, and 2,613 KRW per month per household. Ⅳ. Dissemination of Research Outcomes □ Performance review of municipalities’ water services ○ Authors proposed the performance review method of municipalities’ water services by using the Data Envelopment Analysis methodology and the collected data in this study. Two input variables (number of staff and operating expense) and four output variables (water supply coverage, revenue water ratio, GIS mapping coverage, and water pipe length) of 154 small- and mid-scale municipalities are determined from the panel data from 2016 to ’19년. The result indicates that the efficiency of water service has been increasing. The absolute efficiency level, however, is low, and the deficiency in the operation efficiency is significant. ○ It is considered that the data collected in this study can be used for the performance review or for developing a benchmarking program of municipalities’ waterworks and sewerage services. □ Utilization of the sustainability index ○ The sustainability index of this study can be used in the trend analysis of the level of water services. It can help identify the issues in water service and water infrastructures and track the outbreak points of certain problems. The framework and methodology of the sustainable index can be used as a reference in developing new indicators on the public’s experience of water services or the sub-indicators of the sustainable development goal on water and sanitation (SDG 6). Ⅴ. Conclusions ○ The gap in the economic sustainability indexes between the municipalities of different sizes lasted from 2015 to ’19년. For social sustainability, the indicators on service coverage and facility installation have been improved. The economic and social indicators imply that the small municipalities should improve the cost recovery ratio in water and sewage services, taking the affordability issue into consideration at the same time. Respondents with higher awareness on the importance of water services showed a greater willingness to pay for projects to improve water services. ○ While water environment, water supply, and sewage services are regarded as important issues by the public, their satisfaction level of water services was relatively low. It indicates that citizens’ awareness and satisfaction level of water services are a significant matter in water policy. ○ Authors will continue to carry out the sustainable assessment of water service and water infrastructures with updated data and will propose the ways to disseminate the research results.

임계치 모형과 인공신경망 모형을 이용한 실시간 저수지 수위자료의 이상치 탐지

김마가,최진용,방재홍,이재주 한국농공학회 2019 한국농공학회논문집 Vol.61 No.1

Reservoir water level data identify the current water storage of the reservoir, and they are utilized as primary data for management and research ofagricultural water. For the reservoir storage management, Korea Rural Community Corporation (KRC) installed water level stations at around 1,600agricultural reservoirs and has been collecting the water level data every 10 minutes. However, various kinds of outliers due to noise and erroneousproblems are frequently appearing because of environmental and physical causes. Therefore, it is necessary to detect outlier and improve the qualityof reservoir water level data to utilize the water level data in purpose. This study was conducted to detect and classify outlier and normal data usingtwo different models including the threshold model and the artificial neural network (ANN) model. The results were compared to evaluate theperformance of the models. The threshold model identifies the outlier by setting the upper/lower bound of water level data and variation data and bysetting bandwidth of water level data as a threshold of regarding erroneous water level. The ANN model was trained with prepared training datasetas normal data (T) and outlier (F), and the ANN model operated for identifying the outlier. The models are evaluated with reference data which werecollected reservoir water level data in daily by KRC. The outlier detection performance of the threshold model was better than the ANN model, butANN model showed better detection performance for not classifying normal data as outlier.

우리나라 저수지에서 지형, 수문, 수질 및 호안 토양 환경요인의 분석

조현석 ( Hyun Suk Cho ),조강현 ( Kang Hyun Cho ) 한국하천호수학회 2013 생태와 환경 Vol.46 No.3

In order to understand shoreline environment characteristics of Korean reservoirs, the interrelationships between environmental factors of geomorphology, hydrology, water quality and shoreline soil were analyzed, and the reservoir types were classified according to their environmental characteristics in the 35 reservoirs selected by considering the purpose of dam operations and annual water-level fluctuations. Geomorphological and hydrological characteristics of reservoirs were correlated with the altitude and the size scale of reservoirs. The annual range of water level fluctuation showed a wide variation from 1 m to 27 m in the various reservoirs in Korea. The levels of eutrophication of most reservoirs were mesotrophic or eutrophic. From the result of the soil texture analysis, sand contents were high in reservoir shorelines. Range, frequency and duration of water-level fluctuation were distinctive from the primary function of reservoirs. Flood control reservoirs had a wide range with low frequency and waterpower generation reservoirs had a narrow range with high frequency in the water-level fluctuation. According to the result of CART (classification and regression tree) analysis, the water quality of reservoirs was classified by water depth, range of water-level fluctuation and altitude. The result of PCA (principal component analysis) showed that the type of reservoirs was classified by reservoir size, water-level fluctuation, water quality, soil texture and soil organic matter. In conclusion, reservoir size, the water-level fluctuation, water quality and soil characteristics might be major factors in the environment of reservoir shorelines in Korea.

PID 제어기로 급수탑의 수위제어를 구현한 융·복합 공정자동화 시뮬레이션에 관한 연구

조현성 한국전시산업융합연구원 2019 한국과학예술융합학회 Vol.37 No.4

Water tank level controls operate in unstable conditions that often exceed the setpoint level. This study was started to solve this problem because it is important to keep the water or liquid level at the desired level in applications such as chemical plant or industrial processes. The purpose of this study was to attempt to maintain a constant level using the Modular based Process Control System (MPS) for the Fourth Industrial Revolution, because unstable water levels generally cause damage to equipment and device in the manufacturing process. In this working, we present to adjust the flow rate of water flowing into the water tank and controlled the water level by changing the speed of the DC motor water pump filling the upper water tank from the lower water tank. The control methods applied at this time are four types: manual and open circuit control, manual and closed circuit control, automatic and open circuit control, and automatic and closed circuit control. As a result of comparing the four control methods, continuous control using the automatic closed circuit control system is easy to support the water supply smoothly. However, due to the performance limitations of the impeller motor, the graph of the relationship between the flow rate and the current indicating the performance of the pump shows a dual characteristic. Therefore, an optimal capacity pre-review should be preceded to minimizing unbiased pump performance based on the research results. This work was demonstrated by MPS® EduKit-PA and FluidLab®-PA software from Festo-didactic, Germany. 물탱크 수위조절장치는 자주 설정수위를 넘나드는 불안정한 조건에서 운영된다. 본 연구는 도금과 같은 화학공정이나 산업공정과 같은 응용분야에서 물 또는 액체의 수위를 원하는 수준으로 유지하는 것이 중요 하기 때문에 이 문제를 해결하기 위해 시작되었다. 본 연구의 목적은 불안정한 수위가 일반적으로 제 조공정의 장치와 장비의 손상을 초래하기 때문에 이 러한 문제를 해결하기 위해 4차 산업혁명의 모듈러 공정제어 장치(MPS)를 사용하여 일정한 수위를 유지 하도록 시도하였다. 연구내용은 하부 물탱크에서 상부 물탱크를 채우는 DC모터 물 펌프의 속도를 변경하여 물탱크로 유입되 는 물의 흐름속도를 조정하고 수위를 제어하였다. 이 때 적용한 제어방식은 수동·개방 회로제어, 수동·폐쇄 회로제어, 자동·개방 회로제어, 자동·폐쇄 회로제어로 4종류이다. 4종류의 제어방식을 비교하여 본 연구결과, 물의 공 급을 원활하게 지원하기 위해 자동·폐쇄 회로제어 시스 템을 이용하면 융·복합 공정자동화를 위한 연속적인 제 어가 용이하다. 그러나 임펠러 모터의 성능 한계로 인 해 펌프의 성능을 나타내는 유량과 전류의 상관관계를 나타내는 곡선이 이원화된 특징을 보였다. 이러한 연구 결과를 바탕으로 불안정한 펌프성능의 최소화를 위한 최적의 용량검토에 대한 선행 연구가 기대된다. 시험 장치로써 독일 페스토다이덱틱사의 MPS® EduKit-PA 와 소프트웨어는 FluidLab®-PA를 활용하였다.