MODFLOW 모형을 이용한 부곡온천지역 지하수 유동해석

정상옥,이영대,민병형,Chung, Sang-Ok,Lee, Young-Dae,Min, Byung-Hyung 한국수자원학회 1994 물과 미래(한국수자원학회지) Vol.27 No.1

부곡온천 지역의 지속적인 지하수위 하강에 대비하여 온천지역의 지하수 흐름을 3차원 모형인 MODFLOW를 이용하여 해석하였다. 연구 결과를 요약하면 다음과 같다. 1) 변수보정 과정에서 대수층의 투수계수는 0.0134m/d로, 저류계수는 0.020으로 나타났으며, 모형이 추정한 장기간의 지하수위 변동은 관측치와 잘 맞았다. 2) 여러 가지 시나리오에 대하여 1년간의 기간에 대한 시뮬레이션을 한 결과 가장 나쁜 조건인 년간 함양량이 작고 년간 양수량이 큰 경우에는 시뮬레이션 기간의 초기에 비해 말기에 지하수위가 저하되었으나 그 외의 경우에는 말기의 수위가 초기의 수위보다 낮아지지 않았다. 3) 온천지역의 안전채수량은 함양율의 크기와 지하수위의 고저에 크게 영향을 받는 바, 양수량의 결정은 년중 지하수위가 가장 낮은 4월경에 과다한 수위저하가 발생하지 않도록 하여야 한다. This study was conducted to analyse groundwater flow in the Bugok hot spring area using the MODFLOW model which can simulate three dimensional groundwater flow both in confined and unconfined aquifers. Based on this study the following conclusions were obtained: 1) The hydraulic conductivity and the specific storage of the aquifer were 0.0135 m/day and 0.020, respectively, and the model-predicted groundwater elevation agreed well with the observed one. 2) Simulation results showed that the groundwater level declines at the end of the one-year simulation period when the annual recharge rate is small and the annual pumping rate high, which is the worst combination. Except that combination, the groundwater level does not decline at the end of one-year simulation period indication the pumping rates used were allowable. 3) The safe yield depends upon the magnitudes of the recharge and pumping rates. The pumping rate should not produce excess decline of groundwater level around April when the water level is the lowest in a year.

벼 직파재배기법 및 천수간단 관개기법

정상옥,안태홍,Chung Sang-Ok,Ahn Tae-Hong 한국관개배수위원회 2001 한국관개배수논문집 Vol.8 No.1

민물말류 군집 생태 연구시 생체량 계산의 의미와 예

정상옥,Chung, Sang-Ok 한국조류학회(藻類) 2004 ALGAE Vol.19 No.2

Freshwater algae make up a very important portion of the autotrophic component of the aquatic food web. Therefore, the study of freshwater algal structure and biomass is central to aquatic ecosystem studies. Due to variations in cell shape and size for each species (or taxon) and survey site, cell abundance (or cell numbers per chosen volume) often leads to misrepresentation of the true importance of some species because of the great differences in size of various algae. Thus, it is necessary to investigate the freshwater algal species of a site in order to calculate the cell volume. Although direct cell counting, species volume measurement, as well as biomass calculation are time-consuming and requiring specialists in taxonomy.

농업배수가 수질에 미치는 영향과 오일저감 대책

정상옥,Chung Sang-ok 한국관개배수위원회 1996 한국관개배수논문집 Vol.3 No.2

Recently, the interests on the effects of agricultural drainage on surface and ground oater quality have been increased. Water pollution in the rural area has been increasing because of agricultural activities and industrialization. Increased use of agric

FAO-AquaCrop을 이용한 기후변화가 벼 증발산량 및 수확량에 미치는 영향 모의

정상옥,Chung, Sang-Ok 한국농공학회 2010 한국농공학회논문집 Vol.52 No.3

The impacts of climate change on yield and evapotranspiration of rice have been modeled using AquaCrop model developed by Food and Agriculture Organization (FAO). Climate change scenario downscaled by Mesoscale Model 5 (MM5) regional model from ECHO-G General Circulation Model (GCM) outputs by Korea Meteorological Research Institute (METRI) was used in this study. Monthly average climate data for baseline (1971-2000) and three time periods (2020s, 2050s and 2080s) were used as inputs to the AquaCrop model. The results showed that the evapotranspiration after transplanting was projected to increase by 4 % (2020s), 8 % (2050s) and 14 % (2080s), respectively, from the baseline value of 464 mm. The potential rice yield was 6.4 t/ha and water productivity was 1.4 kg/$m^3$ for the baseline. The potential rice yield was projected to increase by 23 % (2020s), 55 % (2050s), and 98 % (2080s), respectively, by the increased photosynthesis along with the $CO_2$ concentration increases. The water productivity was projected to increase by 19 % (2020s), 44 % (2050s), and 75 % (2080s), respectively.

논지대 수계환경에서 농약의 노출위험도 분석

정상옥 ( Chung Sang-ok ),박기중 ( Park Ki-jung ) 한국농공학회 2007 한국농공학회 학술대회초록집 Vol.2007 No.-

Exposure risk assessment of pesticide molinate in rice paddy areas was performed to see the effects of various water and pesticide management scenarios and then best management practices were proposed to prevent adverse effects on populations. The results of the RICEWQ model simulation from the previous studies were analyzed. The pesticide risk for aquatic organisms is evaluated by the ratio of the predicted environmental concentration (PEC) and the predicted no-effect concentration (PNEC). To assess the exposure risk to the aquatic organisms, predicted molinate concentrations were grouped into four risk classes. The no risk concentration range is lower than 0.002 mg/L, the low is from 0.002 mg/L to 0.01 mg/L, the moderate is from 0.01 mg/L to 0.1 mg/L, and the high is above 0.1 mg/L. The critical values for each category were calculated from the toxicity endpoint value (median lethal concentration, LC50) divided by the assessment factor (AF). The results showed that the very shallow ponding depth in rice paddies showed lower pesticide exposure risk than the deep ponding depth, and the higher application rate showed greater exposure risk to the aquatic organisms. The results of this study can be used for the non-point source pollution control and environmental policy making regarding pesticides.

Scenario-Based Exposure Risk Assessment of Molinate in a Paddy Plot : (1) Analysis of simulation results

정상옥,박기중,손성호,Chung, Sang-Ok,Park, Ki-Jung,Son, Seung-Ho The Korean Society of Agricultural Engineers 2008 한국농공학회논문집 Vol.50 No.2

The effects of water and pesticide management practices on ponded water pesticide concentrations in a paddy plot were analysed using the RICEWQ model. The molinate which is a herbicide widely used in rice culture, and frequently detected in paddy environment was selected. In a previous study, the RICEWQ model was successfully calibrated with field data obtained from a paddy plot in Daegu. The calibrated model was run using water and pesticide management scenarios with a set of measured meteorological data for 1997-2006 in Daegu. For all three ponded water depths with the label rate application, the amount of molinate dissipated in ponded water and volatilized accounted for more than 70%, and the runoff losses were less than 9%. The molinate losses through drainage in the very shallow ponded depth showed 40% less than that in deep ponded depth. Comparing with the deep and shallow ponded depth, the very shallow depth was the best with regards to the reduction of molinate runoff losses. Simulations with different pesticide application rates, label rate and double label rate, showed molinate concentrations in the ponded water increased linearly with the application rate increase.

논 관개용수 수온상승 방법의 검토

정상옥 ( Sang-ok Chung ) 한국농공학회 2011 한국농공학회 학술대회초록집 Vol.2011 No.-

다목적 댐 또는 용수전용 댐으로부터 농업용수를 공급할 때 표층수 취수를 하지 않는 경우 낮은 수온으로 인하여 하류 논에서 냉수피해를 입을 수 있다. 이에 대한 대책으로 수온상승 시설을 설치하거나 다른 대책을 세워야 한다. 본 고에서는 우리나리의 기존 온수시설인 소양강 댐 하류의 우두 온수지, 충주댐 하류의 용교 온수로 및 온수지, 주암조절지 댐 하류의 온수지 현황과 수온상승 효과를 소개하였다. 또한 용수전용 댐 (운문댐, 영천댐)은 농업용수는 물론 상수원수를 공급하기 때문에 수질 문제로 하층수를 취수하고 있으며 따라서 하류 농지에서 냉수피해를 입어 오고 있다. 운문댐 및 영천댐 하류의 냉수피해를 소개하고 이에 적정하게 대처할 수 있는 방안들을 소개하였다. 운문댐에서는 수심별 수온 측정 자료로부터 표수층의 깊이를 산정하여 표층수 취수나 온수지 대용의 보로 부터의 취수를 건의한 바 있다. 운문댐관리단에서는 수온 상승 방법으로 흙 수로를 콘크리트 수로로 개수하였다. 영천댐에서는 수심별 수온 측정 자료로부터 표수층의 깊이를 조사하고 댐 하류에 설치된 보의 상류지점과 농업용수 취수문 지점의 수심별 수온을 관측하여 수심별 수온분포를 조사하였다. 본 연구에서 검토한 결과 영천댐 하류의 온수대책으로는 댐 표층수 취수 (취수탑의 상부 취수공 취수 또는 취수 pontoon 이용)를 하는 방안을 제시하였으나 상수원수 취수와의 상충되는 문제를 해결하여야 할 것이다. 그 외에 보 상류 농업용수 취수문을 하층수를 취수하는 승강식 수문 (lift gate)이 아닌 표층으로부터 취수할 수 있는 전도식 수문 (flap gate)이나 드럼 수문 (drum gate)을 설치하는 것도 한 방법으로 제시하였다. 또한 취수구의 위치를 최대한 하류측인 보 가까이로 옮겨서 댐 방류수가 취수구까지 오는 사이에 약간의 수온상승을 기대할 수 있다. 그러나 이 두 가지 방법으로는 큰 효과는 얻기 어려울 것이다. 댐의 표층수 취수와 함께 가장 효과적인 방법인 온수지 건설은 적당한 부지 선정의 어려움과 경제성를 고려하면 채택하기 어려운 대안이다. 농민들의 자발적인 동참으로 효율적인 물관리를 통한 냉수피해 저감방안이 좋은 대안이라고 판단된다.

비점원 오염관리를 위한 식생여과대의 적용

정상옥,정지은,Chung Sang-Ok,Chung Ji-Eun 한국관개배수위원회 2002 한국관개배수논문집 Vol.9 No.1

직파재배 벼의 영농기법 및 비용 절감 효과 - 현장 사례 연구

정상옥 ( Chung Sang Ok ),김지용 ( Kim Ji Yong ),안태홍 ( Ahn Tae Hong ) 한국농공학회 2000 한국농공학회 학술대회초록집 Vol.2000 No.-

A field case study was performed to investigate optimum cropping technique of direct seeded rice. In addition, an economic analysis was made to see the effect of this method. Field study was performed at a 2.1㏊ paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding method such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Optimum cropping techniques such as when and how to manage the rotary till, water supply, herbicide application, and ponding depth were developed for different cropping methods. Based on this study ￦640,000 per ㏊ can be saved by direct seeding due to no nursery cost, and ￦1,220,000 per ㏊ can be saved by no-till and no nursery cost. With further study these cropping techniques including the no-till direct deeding proves to be advantageous these can be adopted for the most of the paddy fields in Korea.