• 한국농공학회논문집
• /
• 제60권6호
• /
• pp.65-71
• /
• 2018

The Long-Term Hydrologic Impact Assessment (L-THIA) model is a quick and straightforward analysis tool to estimate direct runoff and nonpoint source pollution. L-THIA was originally implemented as a spreadsheet application. GIS-based versions of L-THIA have been developed in ArcView 3 and upgraded to ArcGIS 9. However, a major upgrade was required for L-THIA to operate in the current version of ArcGIS and to provide more options in runoff and NPS estimation. An updated L-THIA interfaced with ArcGIS 10.0 and 10.1 has been developed in the study as an ArcGIS Desktop Tool. The model provides a user-friendly interface, easy access to the model parameters, and an automated watershed delineation process. The model allows use of precipitation data from multiple gauge locations for the watershed when a watershed is large enough to have more than one precipitation gauge station. The model estimated annual direct runoff well for our study area compared to separated direct runoff in the calibration and validation periods of ten and nine years. The ArcL-THIA, with a user-friendly interface and enhanced functions, is expected to be a decision support model requiring less effort for GIS processes or to be a useful educational hydrology model.

• 한국물환경학회지
• /
• 제25권6호
• /
• pp.849-854
• /
• 2009

Pollutant unit load (unit-load) reported by Ministry of Environment (MOE) in 1995 has been a useful method for watershed management and environmental policy decision. The unit-load has been estimated using effective rainfall ratio method. However, reliability of unit-load determined by the method has been criticized especially for paddy field and upland conditions. In this paper the unit-load of paddy field estimated by effective rainfall ratio method was compared with continuous monitoring data. Annual loads was simulated by the method choosing 5~6 storm events randomly from whole events collected. Probability distribution of difference between results by the method and measured data was investigated. The results showed that unit-load derived by the method was generally lesser than measured unit-load and showed wide variations. Therefore, unit-load estimation of paddy fields by effective rainfall ratio method need caution.

• 대한환경공학회지
• /
• 제33권2호
• /
• pp.103-112
• /
• 2011

본 연구에서는 기존의 질소 수지에 관한 연구를 바탕으로, 우리나라의 2008년 질소의 총 유입과 유출을 수지분석 방법을 이용하여 추정하였다. 질소의 유 출입은 도시지역, 농 축산지역, 임야지역의 세부분으로 나누어 산출하였다. 질소의 주요 유입으로는 화학적, 생물학적 질소고정, 건식 및 습식 침착량, 해외로부터 수입된 양 등이 있으며, 유출된 양은 작물흡수, 휘발, 탈질, 침식, 표면유출, 산림소비 등으로 결정하고 그 양을 추정하였다. 연간 질소의 총 유입량은 1,294,155 ton/yr이며, 총 유출량은 632,228 ton/yr이었다. 질소수지를 기존의 2005년 질소 수지와 상호 비교 및 분석한 결과, 2008년도에 총 유입된 질소는 2005년 질소유입 보다 1.9% 저감된 것으로 조사되었다. 총 유입 질소의 감소는 질소비료 사용량 감소, 국토 개발, 경작지 감소 등으로 인한 결과이며 총 유출 질소는 6.3% 감소하였다. 질소 수지 분석에 의한 연간 발생한 비점오염의 양을 추정해본 결과, 2005년도에 연구되었던 질소 수지량에 비해서 22% 증가한 것으로 조사되었다. 탈질로부터 아산화질소 배출량을 산정하였는데, 농업지역과 하수처리장에서 약 8,289 ton/yr이 배출되었다.

• 한국환경농학회지
• /
• 제20권3호
• /
• pp.192-200
• /
• 2001

우리 나라의 농업지대 소유역에서 질소와 인의 부하에 대한 농업비점오염 모형 AGNPS의 적용 가능성을 검토하고자 경북 영천군 임고천 유역에서 조사된 실제 강우사상에 대하여 강우사상별로 실측치와 모형의 예측치를 비교하였다. CN 식에 대한 보정을 거친 모형을 적용한 결과, 첨두유량은 강우에 따라 다소 차이는 있었으나 예측치는 모형효율 0.97로 실측치와 거의 일치하였다. 이는 유역의 특성을 고려하여 CN 식을 수정하였고 유역의 동질성을 위해 격자망을 비교적 세분화하였기 때문으로 판단된다. 총 질소와 총인 농도의 경우의 실측치와 예측치를 비교하면 모형효율은 각각 0.93과 0.74였으며, 총인의 경우 총질소에 비해 결정계수가 비교적 낮은 것은 토지 이용에 따른 시비 및 생활 및 축산 오수 유입 등의 차이에 상대적으로 민감하게 영향을 받았기 때문으로 판단된다. 농업비점오염 부하를 예측하는 모형인 AGNPS는 적용 대상 유역의 특성을 잘 고려하여 매개변수들을 적절히 보정하고 정확한 입력자료를 확보하면 우리 나라 소규모 농업 유역에서도 활용될 수 있을 것으로 판단된다.

• 한국물환경학회지
• /
• 제16권4호
• /
• pp.491-499
• /
• 2000

Effluent concentration estimation equations for treatment wetland were reviewed with 3 -year experimental data. Four equations from USEPA, WPCF, Kadlec and Knight, and this study were applied to the over 100 data points of 1996 to 1999 study at the pilot plant in Konkuk University. The system was a subsurface flow type and consisted of 60cm depth of sand and reeds, and it worked continuously including winter with domestic sewage from school building. Generally, all the equations demonstrated reasonable agreement with experimental data and they could be used for design process if selected carefully. Among them, the equation from this study showed the best fit for the data. The reason might be not only the equation was derived from the experimental data, but also it included plant coverage parameter in the equation while others did not Plant coverage was proved to be an important parameter in the prediction of the treatment wetland system, and its inclusion in the estimation equation could improve the accuracy. Although existing equations could be used in the wetland design, pilot plant experiment for the anticipated condition and subsequent equation development can provide more reliable equation. It takes time to obtain meaningful data from wetland system. Therefore, timely onset of well organized study is recommended before large scale application of treatment wetland system to either point or nonpoint source pollution abatement.

• 한국농공학회논문집
• /
• 제47권5호
• /
• pp.87-97
• /
• 2005

The field scale experiment was performed to examine the effect of physical design parameters on the constructed wetland performance and recommend the feasible design of constructed wetland in Korean polder areas. Four sets (each set of 0.85 ha) of wetland (0.8 ha) and pond (0.08 ha) systems were used. Two different wetland systems, a wetland-pond system and a pond-wetland system, were studied to examine the effect of wetland and pond configuration. And two different length-to-width ratios were used, 2: 1 and 0.8: 1, to examine the effect of aspect ratio. A pond-wetland system was more preferable than a wetland-pond system, and also requires a smaller area than a wetland-pond system or a wetland system to reduce T-P. There was no difference in effluent concentration between the 2:1 system and the 0.8:1 system. Although the linear velocity of the 2:1 aspect was higher than the 0.8:1 aspect, resuspension was not a factor in this study due to a very low linear velocity. From this study and other literature review, it was found that design method of paddy rice field could be applied and expanded to the design of constructed wetland in Korea. Further investigation for the detailed design parameters of constructed wetland needs be continued for design method of paddy rice to be applied in full scale.

• 한국농공학회논문집
• /
• 제56권6호
• /
• pp.85-91
• /
• 2014

In this study, the water quality purification of new medias which were NPS media, hyugato, mineral stone, charcoal for applying soil media of Integrated Management Practices (IMPs) of Low Impact Development (LID) were evaluated. The influent concentrations of COD, T-N, and T-P were 117.8 mg/L, 17.1 mg/L, and 2.062 mg/L, respectively. The infiltration capacities of NPS media, hyugoto, mineral stone, charcoal, and gravel were $7.1{\times}10m/s$, $7.3{\times}10^{-5}m/s$, $7.9{\times}10^{-5}m/s$, $6.0{\times}10^{-5}m/s$, respectively. All media meet criteria of infiltration capacity as surface soil layer at IMPs which is over $1.0{\times}10^{-5}m/s$. Maximum removal rates of COD, T-N, and T-P occurred at Charcoal with 98 % of COD removal rate, NPS with 78 % of T-N removal rate, and hyugato with 75 % fo T-P removal rate, respectively. For more high removal efficiency of all water quality item, the mixed media which is 4.5(NPS media): 1(charcoal) : 4.5 (hyugato) as volume ratio was evaluated. The infiltration capacity of mixed media was $7.9{\times}10^{-5}m/s$ and met the criteria of infiltration as surface soil layer. The water quality removal efficiencies of mixed media were very high with showing 70 % for COD, 85 % for T-N, and 71 % for T-P. The mixed media could purify the water quality of surface runoff and was recommended to used at the LID site of ground water quality problem.

• 한국농공학회지
• /
• 제44권4호
• /
• pp.139-148
• /
• 2002

Pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent from December 2000 to June 2001. The wetland system used for the experiment was highly effective to treat the sewage during the growing season, but it was less effective and its effluent was still high to discharge to the receiving water body. Therefore, the wetland effluent may need further treatment to prevent water quality degradation. Pond system could be used to hold and further polish the wetland effluent during the winter season and ots feasibility was evaluated in this study. Additional water quality improvement was apparent in the pond system during winter season, and the pond effluent could be good enough to meet the effluent water quality standards if it is properly managed. Timing of the pond effluent discharge appears to be critical for pond system management because it is a closed system and whole water quality constituents are affected by physical, chemical, and biological pond environments. Once algae started to grow in mid-April, constituents in the pond water column interact each other actively and its control becomes more complicated. Therefore, upper layer of the pond water column which is clearer than the lower layer my need be discharged in March right after ice cover melted. In the experiment, water quality of the upper water column was markedly clear in March than ant other times probably because of freezing-thawing effect. The remaining lower water column could be further treated by natural purification as temperature goes up or diluted with better quality of wetland effluent for appropriate water uses. This study demonstrated the feasibility of pond system for subsequent management of wetland effluent during the winter season, however, more study is needed for field application.

• 농업과학연구
• /
• 제43권3호
• /
• pp.424-431
• /
• 2016

The nutrients in livestock manure produced during fermentation processes in public livestock recycling centers are used as fertilizers. However, the large amounts of swine manure produced in intensive livestock farms can be a nonpoint source of pollution. In this experiment, we investigated the chemical properties, inorganic components, and heavy metal contents in 101 samples of liquid swine manure collected from 28 public livestock recycling centers throughout the nation. Results showed that the average pH of the samples was alkaline (pH range 5.18 to 9.54), and their maximum EC was $53.2dS\;m^{-1}$. The amounts of total nitrogen and total phosphorus were in the range of 1000 - 2000 and $200-800mg\;L^{-1}$ while potassium, which constituted 47% of the total inorganic ions recovered from the liquid swine manure, amounted to $1500mg\;L^{-1}$. The most distinctive heavy metals recovered from the liquid swine manure were copper and zinc although the amounts of both heavy metals were much lesser than those of the standards as livestock liquid fertilizer set by the Rural Development Administration. On the other hand, the amount of nitrogen decreased rapidly with an increasing fermentation period from immature to mature, assumed to be lost as volatile compounds, such as ammonia, which are the major odor components during the fermentation process.

• 한국수자원학회논문집
• /
• 제32권4호
• /
• pp.501-510
• /
• 1999

북한강 수계의 농업소유역에 대하여 하천수(2년)와 지하수(1년) 수질을 모니터링하여 분석하였다. 농업소유역의 주요한 비점원 오염물질인 총질소, 질산성 질소, 총인, BOD, TSS 및 대장균 농도를 주기적으로 측정하였다. 계절에 따른 수질의 변화 및 지하수와 하천수 수질과의 관계 비교를 통하여 토지이용이 수질에 미치는 영향을 분석하였다. 연구유역의 지하수 수위와 총질소, 질산성 질소의 농도의 벼농사와 밀접한 관련이 있었고 지하수와 하천수의 질소농도의 변화도 밀접한 관련이 있음이 나타나 벼농사가 하천의 질소농도에 많은영향을 주는 것으로 나타났다. 그러나 토지이용(벼농사)과 지하수 및 하천수의 총인, BOD, 대장균 농도 사이에는 일정한 관계를 발견할 수 없었다. 본 연구결과는 농업소유역의 수질변화를 이해하고 소하천의 수질관리정책을 개발하는데 유용하게 활용될 수 있을 것이다.