The management of agricultural water can be divided into management of agricultural infrastructure and operation to determine the timing and quantity of water supply. The target of water management is classified as water-supply facilities, such as reservoirs, irrigation water supply, sluice gate control, and farmland. In the case of agricultural drought, there is a need for water supply capacity in reservoirs and for drought assessment in paddy fields that receive water from reservoirs. Therefore, it is necessary to analyze the water supply amount from intake capacity to irrigation canal network. The analysis of the irrigation canal network should be considered for efficient operation and planning concerning optimized irrigation and water allocation. In this study, we applied a hydraulic analysis model for agricultural irrigation networks by adding the functions of irrigation canal network analysis using the SWMM (Storm Water Management Model) module and actual irrigation water supply log data from May to August during 2015-2019 years in Sinsong reservoir. The irrigation satisfaction of ponding depth in paddy fields was analyzed through the ratio of the number of days the target ponding depth was reached for each fields. This hydraulic model can assist with accurate irrigation scheduling based on its simulation results. The results of evaluating the irrigation efficiency of water supply can be used for efficient water distribution and management during the drought events.
Analysis and Evaluation of Life SOC in Boeun-gun According to Minimum Criterion of Basic Life Infrastructures
양승환 Yang Seunghwan , 이병준 Lee Byungjun , 윤성수 Yoon Seongsoo
Living infrastructure facilities are concentrated in cities with high population density, it is necessary to supply basic living infrastructure facilities to promote welfare in rural areas. The establishment of basic living infrastructure is the minimum right for daily living of local residents. It is supplied by considering national economic and social characteristics through national minimum standards, but it is limited to be practically applied to rural areas where many villages are dispersed in large areas. There is a situation. Therefore, it is necessary to supply systematic and quantitative facilities by analyzing villages that do not meet the minimum standards of basic living infrastructure in rural areas and by considering their characteristics. The purpose of this study is to identify the basic living infrastructure facilities of village units and analyze the characteristics of each village for Boeun-gun, Chungcheongbuk-do.
Evaluation of Fatigue Resistance of Selected Warm-mix Asphalt Concrete
김성운 Sungun Kim , 이성진 Sung-jin Lee , 김광우 Kwang W Kim
Since some warm-mix asphalt (WMA) concretes were known to show poorer rut resistance than the hot-mix asphalt (HMA) concretes, many studies were performed in efforts of improving its performance at high temperature. The reason is assumed to be due to the moisture remaining in aggregates dried at lower temperature. Therefore, not only the rut resistance, the crack resistance of WMA concrete was also in question. In this study, fatigue life of WMA concrete was evaluated in comparison with HMA using 3-point bending (3PB) beam test. The asphalt mixtures were prepared based on Korean mix-design guide using a 13 mm dense-graded aggregate and 6 binders; two HMA binders and four WMA binders. By 3PB fatigue test, normal (unmodified) and polymer-modified WMA concretes were evaluated in comparison with normal and polymer-modified HMA concretes at a low temperature (-5oC). The results showed that most of WMA concretes showed longer fatigue lives than HMA concretes, even though the same PG binders were used for HMA and WMA. This result indicates that the WMA concretes have stronger resistance against fatigue cracking than HMA at the low temperature, and this result is in contrast to the high-temperature performance test.
Application of Drone Images to Investigate Biomass Management Practices and Estimation of CH4 Emissions from Paddy Fields
박진석 Park Jinseok , 장성주 Jang Seongju , 김형준 Kim Hyungjoon , 홍록기 Hong Rokgi , 송인홍 Song Inhong
Rice paddy cultivation is one of the major sources in methane (CH4) emission of which accurate assessment would be a prerequisite for agricultural greenhouse gas management. Biomass treatment in paddy fields is an important factor that affects CH4 emissions and thus needs to be taken into account. The objectives of this study were to apply drone images to investigate organic matter practices and to incorporate into the estimation of CH4 emissions from paddy fields. Three study areas were selected by one from each of the three different regions of Yeongnam, Honam and Jungbu, which are the most active region in paddy cultivation. The eBee drone was used to take images of the study sites twice a year; Jul mid-season for identifying rice cultivation area; Jan for investigating rice straw management and winter crop cultivation. Based on biomass management practices, different emissions factors were assigned on an individual paddy field and CH4 emmisions were estimated by multiplying respective areas. The ratios of rice straw application and winter crop cultivation were 1.4% and 37.2% in Hapcheon, 1.3% and 19.8% in Gimje, and 0.0% and 0.5% in Dangjin, respectively. The CH4 emissions estimates for respective sites were 0.40 ton CH4/year/ha, 0.34 ton CH4/year/ha, and 0.29 ton CH4/year/ha. On average, estimated CH4 emissions of this study were 28.5% less than the current Tier 2 CH4 emission estimation method.
Drought Hazard Assessment using MODIS-based Evaporative Stress Index (ESI) and ROC Analysis
윤동현 Yoon Dong-hyun , 남원호 Nam Won-ho , 이희진 Lee Hee-jin , 홍은미 Hong Eun-mi , 김태곤 Kim Taegon
Drought events are not clear when those start and end compared with other natural disasters. Because drought events have different timing and severity of damage depending on the region, various studies are being conducted using satellite images to identify regional drought occurrence differences. In this study, we investigated the applicability of drought assessment using the Evaporative Stress Index (ESI) based on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images. The ESI is an indicator of agricultural drought that describes anomalies in actual and reference evapotranspiration (ET) ratios that are retrieved using remotely sensed inputs of Land Surface Temperature (LST) and Leaf Area Index (LAI). However, these approaches have a limited spatial resolution when mapping detailed vegetation stress caused by drought, and drought hazard in the actual crop cultivation areas due to the small crop cultivation in South Korea. For these reasons, the development of a drought index that provides detailed higher resolution ESI, a 500 m resolution image is essential to improve the country’s drought monitoring capabilities. The newly calculated ESI was verified through the existing 5 km resolution ESI and historical records for drought impacts. This study evaluates the performance of the recently developed 500 m resolution ESI for severe and extreme drought events that occurred in South Korea in 2001, 2009, 2014, and 2017. As a result, the two E S Is showed high correlation and tendency using Receiver Operating Characteristics (ROC) analysis. In addition, it will provide the necessary information on the spatial resolution to evaluate regional drought hazard assessment and and the small-scale cultivation area across South Korea.
Improvement to Optimum Equipment Model of Agricultural Reservoir Considering Land Mark
김종봉 Kim Jongbong , 박소연 Park So Yeon , 정남수 Jung Namsu , 이희망 Lee Huimang
Recently, the Yedang reservoir needs reflecting the demands of the public and administration, including change of reservoir status and paradigm shift of users, as well as planning programs to activate the area as a special health zone for tourism, leisure, recreation and experience at the local government level. Previous Optimum Equipment model (OEM) preferentially considers the creation of waterfront. This study shows the operation model for readjustment of water supply facilities according to the limit of the level of the beneficiaries. Results show the renovation cycle of Yedang tourist resort and the suspension bridge through developed model simulation. In addition to securing quantity for the supply of agricultural water and the function of water protection, the multi-function of the agricultural reservoir shall be re-evaluated to enhance the diverse availability of the agricultural reservoir. The county office should also boost various availability at various levels to revitalize the local economy, such as producing pleasant and safe places and offering safe food for people.
A Study on the Resilient Supply of Agricultural Water in Jeju Island by Forecasting Future Demand
고재한 Go Jea-han , 정민혁 Jeung Minhyuk , 범진아 Beom Jina , 성무홍 Sung Mu-hong , 정형모 Jung Hyoung-mo , 유승환 Yoo Seung-hwan , 윤광식 Yoon Kwang-sik
Resilience is the capacity to maintain essential services under a range of circumstances from normal to extreme. It is achieved through the ability of assets, networks, systems and management to anticipate, absorb and recover from disturbance. It requires adaptive capacity in respect of current and future risks and uncertainties as well as experience to date. The agricultural infrastructures with high resilience can not only reduce the size of the disaster relatively, but also minimize the loss by reducing the time required for recovery. This study aims to evaluate the most suitable drought countermeasures with the analysis of various resilience indices by predicting future agricultural water shortage under land use and climate change scenarios for agricultural areas in Jeju Island. The results showed that the permanent countermeasure is suitable than the temporary countermeasures as drought size and the cost required for recovery increase. Wide-area water supply system, which is a kind of water grid system, is identified as the most advantageous among countermeasures. It is recommended to evaluate the capability of agricultural infrastructure against drought with the various Resilience Indices for reliable assessment of long-term effect.
Effects of Saline Irrigation Water on Crop Growth in Strawberry and Red Radish
김수진 Kim Soo-jin , 배승종 Bae Seung-jong , 김학관 Kim Hakkwan , 정한석 Jeong Hanseok
Since the salinity of irrigation water is a critical constraint to the production of certain vegetable crops, salinity was considered as one of the most important factors of irrigation water. The purpose of this study were to monitor and assess the effects of saline irrigation water on strawberry and red radish growth in protected cultivation. One control and three treatments, which were differentiated according to the level of salinity in irrigated water, were employed for each vegetable to assess the effects of the irrigation with saline water. Monitoring has shown that using irrigation water with salinity above a certain level causes excessive accumulation of sodium (Na+) in both strawberry and red radish. Increased Na+ content was analyzed to be able to decrease the sugar content in strawberry. In addition, the salinity higher than the threshold level of irrigation water was found to reduce the growth and yield of strawberry and red radish. This study could contribute to suggest criteria for safe use of saline water in protected cultivation, although long-term monitoring is needed to get more representative results.
Development of Downstream Flood Damage Prediction Model Based on Probability of Failure Analysis in Agricultural Reservoir
전정배 Jeon Jeong Bae , 윤성수 Yoon Seong Soo , 최원 Choi Won
The failures of the agricultural reservoirs that most have more than 50 years, have increased due to the abnormal weather and localized heavy rains. There are many studies on the prediction of damage from reservoir collapse, however, these referenced studies focused on evaluating reservoir collapse as single unit and applyed to one and two dimensional hydrodynamic model to identify the fluid flow. This study is to estimate failure probability of spillway, sliding, bearing capacity and overflowing targeting small and medium scale agricultural reservoirs. In addition, we calculate failure probability by complex mode. Moreover, we predict downstream flood damage by reservoir failure applying three dimensional hydrodynamic model. When the reservoir destroyed, the results are as follows; (1) the flow of fluid proceeds to same stream direction and to a lower slope by potential and kinetic energy; (2) The predicted damage in downstream is evaluated that damage due to building destruction is the highest.
Monitoring the Hydrologic Water Quality Characteristics of Discharge from a Flat Upland Field
박찬우 Park Chanwoo , 오찬성 Oh Chansung , 최순군 Choi Soon-kun , 나채인 Na Chae-in , 황세운 Hwang Syewoon
Converting the agricultural land-use of rice field to upland has been increasingly conducted as farmers encourages themselves to grow higher value-added crops on rice fields under the policy support. Comparing to rice field, Upland shows different characteristic of discharge due to the slope, scale, and shape of field and characteristics of rainfall event. In this study, we designed the experiment fields reflecting flat-upland characteristics with different land scale, and tried to collect the discharge and load data. Soybeans and corn were selected as target crops considering the possibility of large-scale cultivation and crop demand. The cultivation was conducted during the growth period in 2019 with 3 different field scales. Hence, we have collected the discharge data from 17 rainfall events and the load data for 8 rainfall events. As a result, the magnitude of rainfall events and the discharge duration were found to have a strong positive correlation and field discharge occurred during the period by 55% to 83% of rainfall duration. Besides we found other relationships and characteristics of rainfall event, discharge, and pollutant load and also pointed out that continuous monitoring and more data are required to derive statistically significant results. Compared with slope-field monitoring data obtained from the precedent research, the runoff ratio of the flat-fields was significantly lower than slope-fields. Overall the discharge in the slop and flat-fields shows appreciably different characteristics so that the related researches need to be further conducted to reasonably assess environmental impact of agricultural activities at flat-field.
