This study aims to effective survey on actual condition for impact and vulnerability assessment on climate change in agriculture and rural community (limited to rural water and agricultural infrastructure, Paragraph 3, Article 2 of the Rearrangement of Agricultural and Fishing Villages Act) entrusted to Korea Rural Community Corporation based on the Law (Paragraph 2, Article 47 of the Framework Act on Agriculture, Rural community and Food industry). The results are summarized as follows. The rural water was divided into three categories (abnormal climate, water use, and flood control), and 31 indicators were selected. The reservoirs were divided into four categories, and 20 indicators were selected. The pumping stations were divided into two categories, 7 indicators, and the drainage pump stations were divided into two categories, 5 indicators were chosen. A survey on actual condition of each indicator was conducted and the result of the impact assessment was calculated. The 65 rural water showed values ranged from 0.855 to 1.308. The reservoir ranged from 0.966 to 23.338 as a result of the impact assessment on the 16 indicators. The pumping station was able to calculate the results of the safety inspection and the thorough safety inspection, and the drainage pump station was able to calculate only the result of the safety inspection. It is judged that it will be necessary to secure and analyze data on indicators with no data in the future. The results of this research can be utilized as baseline data that can deal with climate change preemptively.
Identifying Priority Area for Nonpoint Source Pollution Management and Setting up Load Reduction Goals using the Load Duration Curve
장선숙 Jang Sun Sook , 지현서 Ji Hyun Seo , 김학관 Kim Hak Kwan
The objective of this study is to identify the priority area where the nonpoint source pollution (NPS) management is required and to set up the load reduction goals for the identified priority area. In this study, the load duration curve (LDC) was first developed using the flow and water quality data observed at 286 monitoring stations. Based on the developed LDC, the priority area for the NPS pollution management was determined using a three-step method. The 24 watersheds were finally identified as the priority areas for the NPS pollution management. The water quality parameters of concern in the priority areas were the total phosphorus or chemical oxygen demand. The load reduction goals, which were calculated as the percent reduction from current loading levels needed to meet target water quality, ranged from 67.9% to 97.2% during high flows and from 40.3% to 69.5% during moist conditions, respectively. The results from this study will help to identify critical watersheds for NPS program planning purposes. In addition, the process used in this study can be effectively applied to identify the pollutant of concern as well as the load reduction target.
Simulating Arsenic Concentration Changes in Small Agricultrual Reservoir Using EFDC-WASP Linkage Model
황순호 Hwang Soonho , 신샛별 Shin Sat Byeol , 송정헌 Song Jung-hun , 윤광식 Yoon Kwang Sik , 강문성 Kang Moon Seong
Even if a small amount of arsenic (As) is entering to small agricultural reservoir from upper streams, small agricultural reservoir becomes sensitive to changes in arsenic concentration depending on the water level in case of accumulation continuously because of its scale. If we want to manage arsenic concentration in small agricultural reservoir, it is very important to understand arsenic changes in agricultural reservoir. In spite of the fact that modeling is the most accurate method for analyzing arsenic concentration changes in small agricultural reservoirs, but, it is difficult to monitor arsenic change everyday. So, if data is prepared for modeling arsenic changes, water quality modeling is more effective than monitoring. Therefore, in this study, arsenic concentration changes was simulated and arsenic concentration change mechanism in small reservoir was analyzed using hydrological and water quality monitoring data and by conducting EFDC (Environment Fluid Dynamics Code)-WASP (Water Quality Analysis Simulation Program) linkage. EFDC-WASP coupling technique was very useful for modeling arsenic changes because EFDC can consider hydrodynamic and WASP can perform arsenic concentration simulation, separately. As a results of this study, during dry season, As concentration was maintained relatively high arsenic concentrations. Therefore, water level control will be needed for managing As concentration of reservoir.
Watershed-scale Hydrologic Modeling Considering a Detention Effect of Rice Paddy Fields using HSPF Surface-Ftable
A method to account a detention in a rice paddy field in hydrologic modeling was tested at plot and watershed scales. Hydrologic Simulation Program - Fortran (HSPF) and its one of surface runoff modeling method, i.e Surface-Ftable, were used to simulate a inundated condition in a rice paddy culture for a study plot and basins in Saemangeum watershed. Surface-Ftable in HSPF defines surface runoff ratio with respect to surface water depth in a pervious land segment, which can be implemented to the feature of water management in a rice paddy field. A Surface-Ftable for paddy fields in Saemangeum watershed was developed based on the study paddy field monitoring data from 2013 to 2014, and was applied to Jeonju-chun and Jeongeup-chun basins which comprise 12% and 22% of paddy fields in the basins, respectively. Four gaging stations were used to calibrate and validate the watershed models for the period of 2009 and 2013. Model performed 7.13% and 9.68% in PBIAS, and 0.94 and 0.90 in monthly NSE during model calibrations at Jeonju and Jeongeup stations, respectively, while the models were validated its applicability at Hyoja and Gongpyung stations. The comparison of results with and without considering detention effect of paddy fields confirmed the validity of the Surface-Ftable method in modeling watersheds containing rice paddy fields.
Surface Cover Effect for Reducing Nitrogen Load in Organic Farming Fields using APEX Model
소현철 So Hyunchul , 장태일 Jang Taeil , 김동현 Kim Dong-hyeon , 설동문 Seol Dong-mun , 윤광식 Yoon Kwangsik
The objectives of this study were to monitor organic farming upland compared with conventional upland field and to evaluate nutrient loads reduction of surface cover effect with long-term historical climate data. APEX(Agricultural Policy Environmental eXtender) model was validated with experimental data and used for assessing surface cover scenarios for 30-year simulation periods. The validated values of RMSE(Root Mean Square Error), RMAE(Root Mean Absolute Error), R2 and E(Nash-Sutcliffe efficiency) for runoff were 1.17-1.37 mm/day, 0.28-0.45 mm/day, 0.88-0.90 and 0.82-0.94 in two treatments, respectively. Those for water quality (nitrogen) were 0.05-0.16 kg/ha, 0.52-0.75 kg/ha, 0.67-0.72 and 0.32-0.70 in two treatments, respectively, and therefore the validated model showed good agreement with the observed runoff and nitrogen load for the study period. When decreasing the surface cover rate of organic farming field to 75%, 50%, 25%, and 0% (conventional field), average annual runoff increased by 7%, 15%, 23% and 31%, respectively. Under same condition of decreasing the surface cover rate, average annual nitrogen loads increased by 1.4 times, 1.7 times, 2.0 times, and 2.3 times compared with organic farming field, respectively. This study showed that it is possible to present an appropriate surface cover ratio to maintain conventional production and minimize nonpoint sources pollution for organic farming system, although long-term monitoring is needed to determine its effects on environmental concerns, crop competition, and other uncertainty.
Climatic Influence on the Water Requirement of Wheat-Rice Cropping System in UCC Command Area of Pakistan
This study investigated climate change influences over crop water requirement (CWR) and irrigation water requirement (IWR) of the wheat-rice cropping system of Upper Chenab Canal (UCC) command in Punjab Province, Pakistan. PRECIS simulated delta-change climate projections under the A1B scenario were used to project future climate during two-time slices: 2030s (2021-2050) and 2060s (2051-2080) against baseline climatology (1980-2010). CROPWAT model was used to simulate future CWRs and IWRs of the crops. Projections suggested that future climate of the study area would be much hotter than the baseline period with minor rainfall increments. The probable temperature rise increased CWRs and IWRs for both the crops. Wheat CWR was more sensitive to climate-induced temperature variations than rice. However, projected winter/wheat seasonal rainfall increments were satisfactorily higher to compensate for the elevated wheat CWRs; but predicted increments in summer/rice seasonal rainfalls were not enough to complement change rate of the rice CWRs. Thus, predicted wheat IWRs displayed a marginal and rice IWRs displayed a substantial rise. This suggested that future wheat production might withstand the climatic influences by end of the 2030s, but would not sustain the 2060s climatic conditions; whereas, the rice might not be able to bear the future climate-change impacts even by end of the 2030s. In conclusion, the temperature during the winter season and rainfall during the summer season were important climate variables controlling water requirements and crop production in the study area.
Assessment and Improvement of Monthly Coefficients of Kajiyama Formular on Climate Change
서지호 Seo Jiho , 이동준 Lee Dongjun , 이관재 Lee Gwanjae , 김종건 Kim Jonggun , 김기성 Kim Ki-sung , 임경재 Lim Kyoung Jae
The Kajiyama formula, which is an empirical formula based on the maximum flood data at Korean watersheds, has been widely used for the design of hydraulic structures and management of watersheds. However, this formula was developed based on meteorological data and flow measured during early 1900s so that it could not consider the recently changed rainfall pattern due to climate changes. Moreover, the formula does not provide the monthly coefficients for 5 months including July and August (flood season), which causes the uncertainty to accurately interpret runoff characteristics at a watershed. Thus, the objective of this study is to enhance the monthly coefficients based on the recent meteorological data and flow data expanding the range of rainfall classification. The simulated runoff using the enhanced monthly coefficients showed better performance compared to that using the original coefficients. In addition, we evaluated the applicability of the enhanced monthly coefficient for future runoff prediction. Based on the results of this study, we found that the Kajiyame formula with the enhanced coefficients could be applied for the future prediction. Hence, the Kajiyama formula with enhanced monthly coefficient can be useful to support the policy and plan related to management of watersheds in Korea.
Exploring the Difficulties Experienced by the Facilitators in the Rural Field Forum
The purpose of this study was to explore the extent of difficulties experienced by facilitators in the rural field forum and to derive a theoretical model for improving the satisfaction of facilitators in the rural field forum. Based on grounded theory, qualitative analysis used data collected through individual in-depth interviews with 10 facilitators who are working at the rural field forum. This collected data was analyzed using the Nvivo 11 program. Using a derived theoretical model, the result of analyzing the difficulties experienced by facilitators in the rural field forum showed the core phenomenon identified as difficulties on-site the forum. There was a clarification of the issues regarding improvement of their labour conditions in order to solve the difficulties on-site the forum. The issues towards improving labour conditions were low allowance, equal assignment, guaranteed four major insurances and so on. The facilitators have been trying to activate the rural field forum by promoting their own capacity through the cooperation between colleagues, post training, seminars, and conferences.
Characteristics of Soil Nutrients by the Application of Rice Straw Ash
In this study physical and chemical characteristics of rice straw ash (RSA) were analyzed in agricultural by-products such as the characteristics of soil pH, electric conductivity (EC), total phosphorus (T-P), available phosphate (Avail-P), and cation exchange capacity (CEC). The results showed that RSA is of mainly C in 95.74% and followed by Si > Al > P > Mg > K > Ca. The pH of RSA was high near 11 and the T-P concentration was 2,322.38±10.35 mg/kg. The specific surface area of RSA was 123.50 m2/g, which was much lower than that of biochar. The X-ray diffraction (XRD) analysis indicated that RSA were C and Si based crystalline. TCLP and KSLT test results implied that the heavy metal concentrations were below the environmental standards and would not impose the risks. T-P concentration increased from 225.59±12.69 mg/kg to 593.39±17.36 mg/kg along with RSA mixing ratio to soil from 0% to 15%. Both pH and EC values were increased with the increase of RSA ratio. The changes in Avail-P and CEC were not when RSA mixing ratio was 1%. whereas the Avail-P concentration was slightly increase when the mixing ratio was more than 5%. Additional investigation considering receiving soil characteristics based on the results of this study would help effective application of RSA to soil.
Water Supply Alternatives for Drought by Weather Scenarios Considering Resilience: Focusing on Naju Reservoir
박진현 Park Jinhyun , 고재한 Go Jeahan , 조영준 Jo Youngjun , 정경훈 Jung Kyunghun , 성무홍 Sung Muhong , 정형모 Jung Hyoungmo , 박현규 Park Hyunkyu , 유승환 Yoo Seunghwan , 윤광식 Yoon Kwangsik
Resilience has been widely used in various fields including design and operation of infrastructures. The resilient infrastructures not only reduce the damage scale of various disasters but also reduce the time and cost required for restoration. However, resilience rarely applied to promote efficient management of agricultural infrastructures. Recently, drought is an aggravating disaster by climate change and need countermeasures. Therefore, we tried to demonstrate evaluating measures in case of drought under consideration of resilience. This study applied the robustness-cost index (RCI) to evaluate alternative solution of the supply problem of a large agricultural reservoir under drought conditions. Four structural alternatives were selected to estimate the robustness index (RI) and the cost index (CI) to obtain the RCI values. Structural alternatives are classified into temporary measures and permanent measures. Temporary measures include the development of a tube wells and the installation of the portable pump, while the permanent measures include the installation of a pumping stations and the pumping water to the reservoir (Yeongsan River-Naju reservoir). RCI values were higher in permanent measures than those of temporary measures. Initial storage of the reservoir also affected RCI values of the drought measures. Permanent measures installation and management of early stage of the reservoir storage shortage was identified as the most resilient system.
Evaluation on the Environmental and Social Value Awareness of the Heat Supply for the Horticultural Greenhouse using Thermal Effluents from Power Plant
김가희 Kim Ga-hee , 안차수 Ahn Cha-soo , 엄병환 Um Byung-hwan
Evaluation on the Environmental and Social Value Awareness of the Heat Supply for the Horticultural Greenhouse using Thermal Effluents from Power Plant
김가희 Kim Ga-hee , 안차수 Ahn Cha-soo , 엄병환 Um Byung-hwan
Recently, interest in alternative energy has been increasing to reduce greenhouse gas emissions and fossil fuel consumption in accordance with the United Nations Framework Convention on Climate Change(UNFCCC). Accordingly, there is a need to use waste heat that unused throughout industrial systems for lowering the concentration of energy on fossil fuels. In particular, government support projects for the energy recycling of agriculture and fisheries such as cultivation of tropical crops and aquaculture are being actively carried out by utilizing waste heat and thermal effluents caused from large-scale industrial complexes including power plants. The study was conducted on supplier (power plant), consumer (farmer) and stakeholders (constructor and local governments) of domestic demonstration areas using waste heat that is abandoned from the power plant in the form of thermal effluents. It investigated the overall improvement and feasibility of government funded projects through field interviews and questionnaire-type surveys. The results of this study are expected to provide basic directions for the operation of the project in terms of nationwide expansion and diffusion of the heat source supply project at horticultural greenhouse by utilizing the thermal effluents from power plant.
Combined 1D/2D Inundation Simulation of Riverside Farmland using HEC-RAS
전상민 Jun Sang Min , 송정헌 Song Jung-hun , 최순군 Choi Soon-kun , 이경도 Lee Kyung-do , 강문성 Kang Moon Seong
The objective of this study was to analyze the characteristics of combined 1D/2D inundation simulation of riverside farmland using the Hydrologic Engineering Center - River Analysis System (HEC-RAS). We compared and analyzed inundation simulation results between 1D and combined 1D/2D hydraulic simulation using HEC-RAS. Calibration and validation of stream stage were performed using three rainfall events. The coefficient of determination (R2) and root mean square error (RMSE) between simulated and observed stream stage were 0.935 - 0.957 and 0.250 m - 0.283 m in calibration and validation, respectively. The inundation area showed no significant difference in 1D and combined 1D/2D simulation (8.48 km2 in 1D simulation, 8.75 km2 in combined 1D/2D simulation). The average inundation depth by 1D simulation was 1.4 m deeper than combined 1D/2D simulation. In the lower inundation depth, the inundation area by combined 1D/2D simulation was larger than inundation area by 1D simulation. As the inundation depth increased, the inundation area by 1D simulation became wider. In the case of the 1D/2D combined simulation, low elevation areas along the river bank were inundated widely. Compared to 1D/2D combined simulation, the flood radius in some sections was longer in 1D simulation. In the 1D analysis, because the low altitude riverside farmlands are also assumed to stream, it is calculated that riverside farmlands have the same stage as the mainstream when the stream is overflowed. Therefore, the inundation area seems to be overestimated in those sections. In other regions, the inundation areas tend to be broken depending on overflow by each stream cross-section. In the case of river flooding, the overflow is expected to flow to the lower area depending on the terrain, such as the results of the combined 1D/2D simulation. It is concluded that the results of combined 1D/2D inundation simulation reflected the topographical characteristics of low-lying farmland.
Development of Representative GCMs Selection Technique for Uncertainty in Climate Change Scenario
정임국 Jung Imgook , 음형일 Eum Hyung-il , 이은정 Lee Eun-jeong , 박지훈 Park Jihoon , 조재필 Cho Jaepil
It is necessary to select the appropriate global climate model (GCM) to take into account the impacts of climate change on integrated water management. The objective of this study was to develop the selection technique of representative GCMs for uncertainty in climate change scenario. The selection technique which set priorities of GCMs consisted of two steps. First step was evaluating original GCMs by comparing with grid-based observational data for the past period. Second step was evaluating whether the statistical downscaled data reflect characteristics for the historical period. Spatial Disaggregation Quantile Delta Mapping (SDQDM), one of the statistical downscaling methods, was used for the downscaled data. The way of evaluating was using explanatory power, the stepwise ratio of the entire GCMs by Expert Team on Climate Change Detection and Indices (ETCCDI) basis. We used 26 GCMs based on CMIP5 data. The Representative Concentration Pathways (RCP) 4.5 and 8.5 scenarios were selected for this study. The period for evaluating reproducibility of historical period was 30 years from 1976 to 2005. Precipitation, maximum temperature, and minimum temperature were used as collected climate variables. As a result, we suggested representative 13 GCMs among 26 GCMs by using the selection technique developed in this research. Furthermore, this result can be utilized as a basic data for integrated water management.
