이혁진 Lee Hyeokjin , 박진석 Park Jinseok , 장성주 Jang Seongju , 고재준 Gou Jaejun , 송인홍 Song Inhong

DOI:10.5389/KSAE.2025.67.4.001 JKWST Vol.67(No.4) 1-11, 2025

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The objectives of this study were to evaluate the impact of riverbed continuity on habitat suitability and ecological flow estimation by comparing the use of cross-section and UAV-based DTM (Digital Terrain Model) in hydraulic models. This study was conducted on the Bokha stream, a 2.5 km reach located in Icheon. To construct the terrain input for hydraulic models, cross-sectional data were surveyed at 10 locations using an EDM instrument, while a high-resolution DTM was generated by integrating UAV-based LiDAR and SfM data, with NDWI applied to enhance accuracy in water-covered areas.. Two hydraulic habitat models, PHABSIM and River2D were applied to simulate the physical habitat conditions to Zacco platypus, the dominant species in the Bokha stream. Using River2D model with UAV-based DTM estimated the optimal ecological flow as 2.76 m³/s, compared to 4.03 m³/s for the cross-section-based River2D and 4.47 m³/s for PHABSIM. These results indicated that while PHABSIM allows for fast and simplified calculations, it tended to overestimate ecological flows due to its limited spatial resolution. In contrast, River2D with UAV-based DTM more accurately capture fine-scale spatial variations, leading to a more realistic estimation of stream habitat conditions.

이희진 Lee Hee-jin , 남원호 Nam Won-ho , 조영현 Cho Younghyun

DOI:10.5389/KSAE.2025.67.4.013 JKWST Vol.67(No.4) 13-23, 2025

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Understanding reservoir storage volume is critical for ensuring a stable water supply and effective management of agricultural reservoirs, which serve as essential infrastructure for irrigation. This study aims to detect and analyze temporal variations in water bodies within ungauged reservoirs, where direct water level measurements are not available, through the application of remote sensing techniques. Optical satellite imagery from the Landsat and Sentinel-2 missions was processed using the Google Earth Engine (GEE) platform. The Normalized Difference Water Index (NDWI) was calculated to enhance water body identification, and the canny edge detection algorithm combined with Otsu thresholding was employed to delineate reservoir boundaries and estimate water surface area. In the case of a gauged reservoir (CT), an R² value of 0.7 was observed between satellite-derived and observed water surface areas during the period of reservoir storage depletion, indicating high accuracy. For the ungauged reservoirs TB and BD, correlation coefficients of 0.35 and 0.61, respectively, were obtained, with improved accuracy associated with larger reservoir size. High accuracy was also achieved in estimating full water surface areas; however, correlation tended to decline during periods of dynamic water level fluctuation. These findings suggest that enhanced spatial resolution in future satellite missions will further improve the detection and monitoring capabilities for water bodies in ungauged agricultural reservoirs.

나라 Na Ra , 김수진 Kim Soo-jin , 주동혁 Joo Donghyuk , 신길채 Shin Gilchai , 유승환 Yoo Seung-hwan , 김영기 Kim Young-ki

DOI:10.5389/KSAE.2025.67.4.025 JKWST Vol.67(No.4) 25-34, 2025

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This study aims to establish a scientific and objective framework for prioritizing agricultural reservoirs for flood warning system implementation in response to increasing flood risks from climate change and aging infrastructure. Out of 3,426 reservoirs nationwide, 1,211 were selected through filtering criteria including safety inspection reports, emergency action plans, reservoir specifications, and flood vulnerability grades. The evaluation framework combines the AHP (analytic hierarchy process) and Entropy weight method, using nine standardized indicators grouped into four categories: watershed characteristics, structural characteristics, vulnerability indicators, and downstream risk. Based on weighted composite scores, reservoirs were classified into four risk levels. The results identified 303 reservoirs in the most critical category, with high concentration in North Gyeongsang Province. Top-priority sites such as Hagok and Wangsin in Gyeongju matched recent disaster records, confirming the validity of the model. This AHP-Entropy-based vulnerability assessment provides a practical tool for phased implementation of flood warning systems for agricultural reservoirs.

신길채 Shin Gilchai , 나라 Na Ra , 주동혁 Joo Donghyuk , 박상빈 Park Sang-bin , 유승환 Yoo Seung-hwan

DOI:10.5389/KSAE.2025.67.4.035 JKWST Vol.67(No.4) 35-49, 2025

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Agricultural reservoirs in Korea have traditionally been managed primarily for irrigation purposes. However, the increasing frequency and intensity of extreme rainfall events driven by climate change have heightened concerns about the potential role of reservoirs in aggravating downstream flooding. In response, the Ministry of Agriculture, Food and Rural Affairs introduced the concept of flood-season managed water levels to promote integrated strategies for both flood control and irrigation supply. This study proposes a practical framework for determining operational rules and optimal management water levels for reservoirs under the jurisdiction of the Korea Rural Community Corporation (KRC) during the flood season. The concept of equivalent rainfall―defined as the maximum rainfall volume that can be fully stored in a reservoir―is applied to evaluate the adequacy of current management criteria. Representative reservoirs were grouped into upper, middle, and lower categories based on their storage-to-drainage area ratios. For each group, corresponding rainfall-storage volume-management water level (R-S-M) curves were developed. These curves were then used to analyze the effectiveness of different pre-release strategies and their implications for post-flood irrigation reliability. Based on the findings, reservoir-specific management water levels are recommended to enhance the flood-season operational efficiency while ensuring adequate irrigation supply.

이채린 Lee Chae-rin , 박지연 Park Ji-yeon , 이세연 Lee Se-yeon , 박진선 Park Jinseon , Daniel Kehinde Favour , 박준수 Park Junsu , 이준엽 Lee Jun-yeob , 김락우 Kim Rack-woo , 홍세운 Hong Se-woon

DOI:10.5389/KSAE.2025.67.4.051 JKWST Vol.67(No.4) 51-61, 2025

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Naturally ventilated (NV) cattle barns contribute significantly to national ammonia emissions, which are precursors to secondary particulate matter in the atmosphere. However, accurately estimating ammonia emissions from NV buildings is challenging due to variations in ventilation rates caused by fluctuating nature of the wind. This study developed a cost-efficient ultrasonic anemometer for direct measurement of ventilation rates in NV cattle barns. The device underwent wind tunnel testing for accuracy validation and used for field experiments conducted in the studied cattle barn for three months. Measured ventilation rates were compared with estimates obtained from the CO₂ tracer gas method and the wind pressure-thermal buoyancy (WT) method to assess measurement reliability. The results indicated that ventilation rates were strongly influenced by external wind speed, with peak values occurring between 12:00 PM and 3:00 PM. The ultrasonic anemometer demonstrated a high correlation with direct wind speed measurements. The CO₂ tracer gas method showed close agreement with direct measurements, with only a 4% difference, indicating its reliability under specific conditions. In contrast, the WT method tended to underestimate ventilation rates, highlighting the need for further calibration. The findings provide valuable insights into ventilation characteristics in NV cattle barns and offer a foundation for improving ammonia emission measurement in NV buildings.

장예근 Jang Ye-geun , 신승훈 Sin Seoung-hun , 이태화 Lee Tae-hwa , 장원석 Jang Won-seok , 신용철 Shin Yongchul , 장근창 Jang Keun-chang , 천정화 Chun Jung-hwa , 김종건 Kim Jong-gun

DOI:10.5389/KSAE.2025.67.4.063 JKWST Vol.67(No.4) 63-63, 2025

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