우리나라 비점원 수질오염 관리의 문제점과 개선방안

권순국(Soon Kuk Kwun) 大韓環境工學會 1998 대한환경공학회지 Vol.20 No.11

전전환답(田轉換畓) 포장(圃場)에서의 지하수위(地下水位) 및 토양수분(土壤水分) 변화(變化) 특성(特性)

권순국 ( Kwun Soon Kuk ),윤경섭 ( Yoon Kyung Sup ) 한국농공학회 1994 韓國農工學會誌 : 전원과 자원 Vol.36 No.2

Experimental studies were conducted to make clear the soil moisture environment under the condition of paddy-upland rotational fields by investigating water-table depths and soil moisture contents during growing season of crops in two kinds of soil. The following results were obtained. 1. Although water-table depths fluctuated with the amount of rainfall in the experimental field, it seemed that the variation of vater4able depths in the paddy-upland rotational, field was strongly affected by the condition of locations on paddy fields. 2. It is recognized that the concept of sum of excess water depth(SEW_xx) and sum of excess water day(SED_xx) can be used to represent the soil moisture stress index due to the fluctuation of water-table depths. 3. The results of this study clearly indicate that drainage in paddy-upland rotational field to maintain an optimum soil moisture content must be made by introducing the concept of block drainage which needs both subsurface drainage and intercept drainage around a field. 4. Soil moisture contents were affected by both the amount of rainfall and water-table depths, however, the moisture content for top soil showed higher correlation with the amount of rainfall while that for subsoil with water-table depths.

한국(韓國)의 논관개시설(灌漑施設) 유지관리(維持管理) 및 물관리(管理)

권순국 ( Kwun Soon Kuk ) 한국농공학회 1989 韓國農工學會誌 : 전원과 자원 Vol.31 No.2

지난 40년간 韓國에서는 농업生産 특히 쌀 생산의 가속화를 위한 노력으로서 灌漑事業에 큰 비중을 두어 왔다. 따라서 灌漑施設과 農地改良에 대한 投資는 괄목할 만큼 伸張되어 1960년 대 이래 총투자액은 美貨 61억달러에 달하고 있다. 그 결과 灌漑에 대한 잠재력과 灌漑面積은 크게 확장되어 지난 40여년간 純灌漑面積은 1945년의 188.200ha로부터 1988년의 195.750ha로 증가 되었으며 이 숫자는 한국 총 畓面積의 73%에 이르는 면적이다. 韓國에는 농업수자원의 開發과 管理를 計劃, 실시하는 임무가 부여된 國家機關이 있다. 그러나 이에 관련되는 국가수준의 機關이 하나이상이므로 관련되는 機關間의 統合이 문제로 제기되고 있다. 이러한 문제는 얼마간 인식되고 있기는 하지만 아직도 심각하게 남아 있다. 農地改良組合 農村近代化促進法에 의하여 조직되고 운영되고 있다. 각 組合에서는 灌漑管理에 대한 政策, 灌漑水 分配計劃 水資源管理 등을 담당하는 管理課가 있으며 또한 각 조합내에는 未瑞水路 및 團場의 물管理를 위한 農民灌漑團體인 흥농계가 조직되고 있다. 農家水準에서의 灌漑開發 및 관리에 關聯되는 問題點 및 주요爭點은 다음과 같음을 확인할 수 있었다. 1. 灌漑組織 및 물 사용의 低效率 2. 몽리구역내의 不均衡한 물分配 3. 水稅의 부과 합리화 및 징수방법 4. 現在의 낡은 灌漑組織 5. 灌漑施設을 效率的으로 운영, 유지관리 하기위한 훈련된 人力 6. 관련 機關間의 統合 韓國의 現 經濟成長 단계에 비추어 볼 때 물의 수요와 水資源의 汚染이 증대되고 있으며 새로운 水資源 開發은 점점 어려워지고 또 高價이다. 따라서 더 이상의 발전을 위해서는 토지와 수자원의 효율적이고 경제적인 이용은 물론 現在 灌漑組織의 개선과 집중적인 管理가 강조 되어야할 것으로 생각된다.

Multiple Box 수질모형(水質模型)에 의한 해남호(海南湖) 수질예측(水質豫測)(II) -개발모형(開發模型)에 의한 미래수질예측(未來水質豫測)-

권순국 ( Kwun Soon Kuk ),신경수 ( Shin Kyung Soo ) 한국농공학회 1991 韓國農工學會誌 : 전원과 자원 Vol.33 No.1

The purpose of this study was the application of a multiple box model for the long term prediction, thus to evaluate different control alternatives of water quality in the Haenam Estuary Reservoir. The result of the study could be summarized as follows ; 1. As input data for the prediction of future water quality, the climatic data in 1980 were used. Also hydrologic data in 1980 as a base year for analysis were simulated with the aid of USDAHL-74/SNUA watershed model. The data for water quality collected in the wateshed, streams and the reservoir were used for determining total inflow pollutant loadings from the source of pollution. The parameter values determined through calibration and verification test of the model were used without any change. 2. The grade of predicted water quality of the Haenam Estuary Reservoir in the future year of 2001 from the base year of 1987 was ranked as Grade I in case of assuming zero pollutant load. Consequently it can be concluded that some alternatives to reduce pollutant load would be needed to improve water quality of the reservoir. 3. The effects of advanced sewage treatment, livestock waste treatment and the drainage of reservoir water through siphon for the improvement of water quality in the reservoir were compared from the simulation result of the model developed. The result showed that the reduction of livestock waste was evaluated as more effective one than any other measures. 4. The grade of water quality in the year of 2001, when applying all treatment at the same time was ranked as Grade III suitable for the domestic use by improving from the Grade IV in 1987, the base year Therefore, it was suggested that combined management of different pollutant sources should be needed to improve or maintain water quality of the Haenam Estuary Reservoir.

산지(山地) 소유역(小流域)의 홍수유출(洪水流出) 예측(豫測)을 위한 모의발생(模擬發生) 수문모형(水文模型)의 개발(開發)

권순국 ( Kwun Soon Kuk ),고덕구 ( Koh Deuk Koo ) 한국농공학회 1988 韓國農工學會誌 : 전원과 자원 Vol.30 No.3

Most of the Korean watersheds are mountaineous and consist of various soil types and land uses And seldom watersheds are found to have long term hydrologic records. The SNUA, a hydrologic watershed model was developed to meet the unique characteristics of Korean watershed and simulate the storm hydrographs from a small mountaineous watershed. Also the applicability of the model was tested by comparing the simulated storm hydrographs and the observed from Dochuk watershed, Gwangjugun, Kyunggido. The conclusions obtained in this study could be summarized as follows ; 1. The model includes the simulation of interception, evaporation and infiltration for land surface hydrologic cycle on the single storm basis and the flow routing features for both overland and channel systems. 2. Net rainfall is estimated from the continuous computation of water balance at the surface of interception storage accounting for the rainfall intensities and the evaporation losses at each time step. 3. Excess rainfall is calculated by the abstraction of infiltration loss estimated by the Green and Ainpt Model from the net rainfall. 4. A momentum equation in the form of kinematic wave representation is solved by the finite differential method to obtain the runoff rate at the exit of the watershed. 5. The developed SNUA Model is a type of distributed and event model that considers the spatial distribution of the watershed parameters and simulates the hydrograph on a single storm basis. 6. The results of verification test show that the simulated peak flows agree with the observed in the occurence time but have relative enors in the range of 5.4-40.6% in various flow rates and also show that the simulated total runoff have 6.9-32% of relative errors against the observed. 7. To improve the applicability of the model, it was thought that more studies like the application test to the other watersheds of various types or the addition of the other hydrologk components describing subsurface storages are needed.

농업수자원으로서의 흡수성 Biofilter 처리수 재이용

권순국 ( Kwun Soon Kuk ),김현욱 ( Kim Hyun Uk ),권용웅 ( Kwon Yong Woong ),조영현 ( Cho Young Hyun ),박상원 ( Park Sang Won ),임경래 ( Lim Kyoung Lae ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.5

Absorbent Biofilter Systems (ABS), composed of an anaerobic septic tank, a pump chamber and an absorbent biofilter tank, have been found to economically provide rural on-site wastewater treatment. This study was conducted to assess the potential of ABS effluent as an alternative water resource for agricultural and environmental use, with respect to the removal of pathogenic microorganism and their fertilization effect. A pilot scale ABS was used to compare its removal efficiency of pathogens from effluent water. Overall, more than 95 percent of Salmonella and E. coli were removed. This result demonstrates that a significant reduction in the pathogenic microorganism of effluents can occur in ABS, which implies the feasibility for the use of ABS effluent in agriculture and environment, with the provision of a further simple disinfection step, in order to satisfy the WHO guidelines for the microbiological quality in agriculture. In addition, because of the abundant nutritional content of ABS effluent, the substitution effect of fertilizer (N, P and K) in paddy irrigation, i.e. 2/3 for nitrogen, l/3 for phosphorus and 1/5 for potassium would be expected. Based on the experimental data, the ABS effluent could be used as a new alternative water resource for paddy irrigation, as well as for environmental purposes, such as supplying water to ecological parks in rural villages.

이상강우에 대비한 성주댐의 홍수조절 능력 분석

권순국 ( Kwun Soon Kuk ),한건연 ( Han Kun Yeun ),서승덕 ( Suh Seung Duk ),최혁준 ( Choi Hyuk Joon ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.6

As a fundamental research to establish a safety operation plan for irrigation dams, this study presents hydrologic analysis conducted in Sungju Dam watershed based on various rainfall data. Especially those reservoirs without flood control feature are widely exposed to the risk of flooding, a safe and optimized operation program need to be improved against arbitrary flooding. In this study, reservoir routing program was developed and simulated for reservoir runoff estimation using WMS hydrology model. The model simulated the variations of reservoir elevation under the condition of open or closed emergency gate. In case of closed emergency gate, water surface elevation was given as 193.15 m, and this value exceeds the dam crest height by 1.65 m. When the emergency gate is open, the increment of water surface elevation is given as 192.01 m, and this value exceeds dam crest height by 0.57 m. As an alternative plan, dam height increase can be considered for flood control under the PMP (Probable Maximum Precipitation) condition. Since the dam size is relatively small compare to the watershed area, sound protection can be expected from the latter option rather than emergency gate installation.

농업(農業) 소유역(小流域)으로 부터의 토양침식(土壤浸蝕) 및 유사량(流砂量) 시산(試算)을 위(爲)한 전산모의(電算模擬) 모델 (I)

권순국 ( Soon Kuk Kwun ) 한국농공학회 1980 韓國農工學會誌 : 전원과 자원 Vol.22 No.4

A deterministic conceptual erosion model which simulates detachment, entrainment, transport and deposition of eroded soil particles by rainfall impact and flowing water is presented. Both upland and channel phases of sediment yield are incorporated into the erosion model. The algorithms for the soil erosion and sedimentation processes including land and crop management effects are taken from the literature and then solved using a digital computer. The erosion model is used in conjunction with the modified Kentucky Watershed Model which simulates the hydrologic characteristics from watershed data. The two models are linked together by using the appropriate computer code. Calibrations for both the watershed and erosion model parameters are made by comparing the simulated results with actual field measurements in the Four Mile Creek watershed near Traer, Iowa using 1976 and 1977 water year data. Two water years, 1970 and 1978 are used as test years for model verification. There is good agreement between the mean daily simulated and recorded streamflow and between the simulated and recorded suspended sediment load except few partial differences. The following conclusions were drawn from the results after testing the watershed and erosion model. 1. The watershed and erosion model is a deterministic lumped parameter model, and is capable of simulating the daily mean streamflow and suspended sediment load within a 20 percent error, when the correct watershed and erosion parameters are supplied. 2. It is found that soil erosion is sensitive to errors in simulation of occurrence and intensity of precipitation and of overland flow. Therefore, representative precipitation data and a watershed model which provides an accurate simulation of soil moisture and resulting overland flow are essential for the accurate simulation of soil erosion and subsequent sediment transport prediction. 3. Erroneous prediction of snowmelt in terms of time and magnitute in conjunction with The frozen ground could be the reason for the poor simulation of streamflow as well as sediment yield in the snowmelt period. More elaborate and accurate snowmelt submodels will greatly improve accuracy. 4. Poor simulation results can be attributed to deficiencies in erosion model and to errors in the observed data such as the recorded daily streamflow and the sediment concentration. 5. Crop management and tillage operations are two major factors that have a great effect on soil erosion simulation. The erosion model attempts to evaluate the impact of crop management and tillage effects on sediment production. These effects on sediment yield appear to be somewhat equivalent to the effect of overland flow. 6. Application and testing of the watershed and erosion model on watersheds in a variety of regions with different soils and meteorological characteristics may be recommended to verify its general applicability and to detact the deficiencies of the model. Futhermore, by further modification and expansion with additional data, the watershed and erosion model developed through this study can be used as a planning tool for watershed management and for solving agricultural non-point pollution problems.

축소단면흐름 형상항력계수

권순국 ( Kwun Soon Kuk ),유동훈 ( Yoo Dong Hoon ) 한국농공학회 1995 韓國農工學會誌 : 전원과 자원 Vol.37 No.3

The efforts of formulation have been reviewed and the results of existing laboratory experiments are investigated in order to describe the contracted flow which occurs at the final closure of sea dike construction. The regional characteristics of contracted flow is analyzed by checking the drawdown curve, and Chezy's mean velocity equation is employed to estimate the discharge rate at the closure. Weir-type discharge equations are reviewed, which are derived from Bernoulli equation, and the problems of the equations are discussed. Chezy's mean velocity equation is considered to be widely and generally applicable, and the empirical factor introduced in Chezy's equation is named 'form drag factor' since it is primarily dependent on the form drag caused by the contraction of discharge area. Laboratory experiments were conducted mainly in order to investigate the variation of form drag factor against various parameters, and an empirical equation is developed for the estimation of form drag factor.

유한요소법(有限要素法)을 이용한 해수유동(海水流動) 해석(解析) (I)

권순국 ( Kwun Soon Kuk ),고덕구 ( Koh Deuk Koo ),조국광 ( Cho Kuk Kwang ),김준현 ( Kim Joon Hyun ) 한국농공학회 1991 韓國農工學會誌 : 전원과 자원 Vol.33 No.4

A numerical simulation of a 2-dimensional tidal flow in a shallow sea was performed using the frequency domain finite element method. In this study, to overcome the inherent problems of a time domain model which requires high eddy viscosity and small time steps to insure numerical stability, the harmonic function incorporated with the linearized function of governing equations was applied. Calculations were carried out using the developed tidal model(TIDE) in a rectangular channel of 10m(depth)×4km(width)×25km(length) under the condition of tidal waves entering the channel closed at one end for both with and without bottom friction damping. The predicted velocities and water levels at different points of the channel were in close agreement with less than 1% error between the numerical and analytical solutions. The results showed that the characteristics of the tidal flow were greatly affected by the magnitude of tidal elevation forcing, and not by on surface friction, wind, or the linear bottom friction when the value was less than 0.01. For the optimum size of grid to obtain a consistent solution, the ratio between the length of the maximum grid and the tidal wave length should be less than 0.0018. It was concluded that the finite element tidal model(TIDE) developed in this study could handle the numerical simulation of tidal flows for more complex geometrical conditions.