• Journal of Wetlands Research
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• v.21 no.3
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• pp.191-198
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• 2019

High impervious surfaces increase the surface runoff during rainfall and reduces the underground infiltration thereby leading to water cycle distortion. The distortion of water cycle causes various urban environmental problems such as urban flooding, drought, water pollutant due to non-point pollution runoff, and water ecosystem damage. Climate change intensified seasonal biases in urban rainfall and affected urban microclimate, thereby increasing the intensity and frequency of urban floods and droughts. Low impact development(LID) technology has been applied to various purposes as a technique to reduce urban environmental problems caused by water by restoring the natural water cycle in the city. This study evaluated the contribution of hydrologic characteristics and water cycle recovery after LID application using long-term monitoring results of various LID technology applied in urban areas. Based on the results, the high retention and infiltration rate of the LID facility was found to contribute significantly to peak flow reduction and runoff delay during rainfall. The average runoff reduction effect was more than 60% at the LID facility. The surface area of the LID facility area ratio(SA/CA) was evaluated as an important factor affecting peak flow reduction and runoff delay effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.545-550
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• 2019

The frequency of natural disasters and the scale of damage are increasing due to the abnormal weather phenomenon occurring all over the world. As a result, as the hydrological aspect of the urban watershed changes, the increase in impervious area leads to serious domestic flood damage due to increased rainfall. In order to minimize the damage of life and property, domestic flooding prediction system is needed. In this study, we developed a flood nomogram capable of predicting flooding only by rainfall intensity and duration. This study suggests a method to set the internal water immersion alarm criterion by analyzing the characteristics of the flooding damage in the flooded area in the metropolitan area where flooding is highly possible and the risk of flooding is high. In addition, based on the manhole and the pipe, the water level was set as follows under the four conditions. 1) When manhole overflows, 2) when manhole is full, 3) when 70% of the pipe is reached, and 4) when 60% of the pipe is reached. Therefore, it can be used as a criterion and a predictive measure to cope with the pre-preparation before the flooding starts, through the rainfall that causes the flooding and the flooding damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.878-886
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• 2018

This study quantified the sounds of riffles and pools in natural rivers and conducted a comparative analysis of the frequency and sound pressure per flow velocity. The surveyed area was Namdaecheon basin in Yangyang-gun, Gangwon-do and the sounds of a total of 23 sites were analyzed. A hydro microphone was used to measure the sound and analyze the data using an acoustic analysis program. The location was also selected at places with minimal ambient noise and the measurement points were the depth of riffles and pools. The results revealed an average difference of 0.515 m/s for flow velocity at 8 riffles and 15 pools. The difference in sound pressure occurred due to the flow velocity. In the case of sound pressure, it was measured at an average of 176.8 dB for riffles and 168.2 dB for pools, demonstrating a difference of approximately 8.6 dB. Furthermore, in the case of maximum sound pressure, riffles showed a constant range between 200 Hz and 250 Hz, while the pools exhibited maximum sound pressure at various frequencies from 200 Hz to 1,000 Hz. This revealed the ecological stream reproduction, development of preferred sound sources for aquatic life, and design of structures.

• Korean Journal of Heritage: History & Science
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• v.54 no.3
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• pp.204-227
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• 2021

This paper proposed the validity and necessity of establishing the Jungwon Historical and Cultural Area by reviewing the historical characteristics of the name Jungwon and its temporal and spatial range. We also explored ways to utilize the Jungwon historical and cultural Area under the Special Act on the Maintenance of Historical and Cultural Areas. Jungwon, which means the center of the country, has strategic value as a key area connecting the Korean Peninsula to the north and south through the Geripryeong and Jukryeong. It also includes Chungju, which connects the Namhan and Bukhan Rivers . From the Mahan period, the areas of Cheongju and Jincheon, the Miho Stream basin to the west, and Chungju to the east were closely connected to each other. Afterwards, Baekje, Koguryo, and Silla engaged in a fierce battle to occupy the Jungwon area. Jungwon culture was born through the negotiation and fusion of the cultures of the three kingdoms. In particular, Silla continued to value the Jungwon area, demonstrated by the installation of Seowongyeong in Cheongju and Bukwongyeong in Wonju, centering on the Jungwongyeong. Since we have a historical view with a focus on ancient kingdoms, we have overlooked the full value of the history and culture of Jungwon. We need to recognize the importance of Jungwon area and think about how to utilize it. Therefore, we suggested in this paper that there be more public information services on the cultural heritage of Jungwon, the historical heritage experience, and the education programs for local residents. The development and operation of Jungwon's history, culture, and tourism contents, as well as the various academic research papers should be used to reveal the identity of the Jungwon historical and cultural area.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2014.10a
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• pp.25-48
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• 2014

Increased frequency of climate extremes is another face of climate change confronted by humans, resulting in catastrophic losses in agriculture. While climate extremes take place on many scales, impacts are experienced locally and mitigation tools are a function of local conditions. To address this, agrometeorological early warning systems must be place and location based, incorporating the climate, crop and land attributes at the appropriate scale. Existing services often lack site-specific information on adverse weather and countermeasures relevant to farming activities. Warnings on chronic long term effects of adverse weather or combined effects of two or more weather elements are seldom provided, either. This lecture discusses a field-specific early warning system implemented on a catchment scale agrometeorological service, by which volunteer farmers are provided with face-to-face disaster warnings along with relevant countermeasures. The products are based on core techniques such as scaling down of weather information to a field level and the crop specific risk assessment. Likelihood of a disaster is evaluated by the relative position of current risk on the standardized normal distribution from climatological normal year prepared for 840 catchments in South Korea. A validation study has begun with a 4-year plan for implementing an operational service in Seomjin River Basin, which accommodates over 60,000 farms and orchards. Diverse experiences obtained through this study will certainly be useful in planning and developing the nation-wide disaster early warning system for agricultural sector.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.367-376
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• 2022

LID technologies are capable of mitigating the negative impacts of non-point source (NPS) pollution generated in different land uses. Apart from the increase in point and non-point pollutant generation, highly developed and paved areas generally affect microclimate conditions. This study evaluated both the efficiency of Low Impact Development (LID) facilities in treating NPS pollutant loads as well as the unit pollutant loads (UPL) generated in various urban features (such as parking lots and highways). This investigation also looked at how LID technology helped to alleviate Urban Heat Island (UHI) conditions. As compared to the typical unit pollutant loads in South Korea, the unit pollutant loads at Kongju National University were relatively low, because of no classes, limited vehicular transmission, and low anthropogenic activities during vacation. After receiving treatment from the LID facilities, the effluent pollutant loads were significantly decreased. The sedimentation in filtration mechanisms considerably reduced the pollutant fractions in the influent. Additionally, it was shown that LID facilities' mean surface temperatures are up to 7.2℃ lower than the nearby paved environment, demonstrating the LID systems reducing the UHI impact on an urban area.

• Journal of Korea Water Resources Association
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• v.55 no.1
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• pp.85-97
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• 2022

In this study, a method for an integrated flood risk mapping was proposed that simultaneously considers the flood inundation map indicating the degree of risk and the disaster vulnerability index. This method creates a new disaster map that can be used in actual situations by providing various and specific information on a single map. In order to consider the human, social and economic factors in the disaster map, the study area was divided into exposure, vulnerability, responsiveness, and recovery factors. Then, 7 indicators for each factor were extracted using the GIS tool. The data extracted by each indicator was classified into grades 1 to 5, and the data was selected as a disaster vulnerability index and used for integrated risk mapping by factor. The risk map for each factor, which overlaps the flood inundatoin map and the disaster vulnerability index factor, was used to establish an evacuation plan by considering regional conditions including population, assets, and buildings. In addition, an integrated risk analysis method that considers risks while converting to a single vulnerability through standardization of the disaster vulnerability index was proposed. This is expected to contribute to the establishment of preparedness, response and recovery plans for providing detailed and diverse information that simultaneously considers the flood risk including social, humanistic, and economic factors.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.969-983
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• 2021

Evapotranspiration, one of the hydrometeorological components, is considered an important variable for water resource planning and management and is primarily used as input data for hydrological models such as water balance models. The FAO56 PM method has been recommended as a standard approach to estimate the reference evapotranspiration with relatively high accuracy. However, the FAO56 PM method is often challenging to apply because it requires considerable hydrometeorological variables. In this perspective, the Hargreaves equation has been widely adopted to estimate the reference evapotranspiration. In this study, a set of parameters of the Hargreaves equation was calibrated with relatively long-term data within a Bayesian framework. Statistical index (CC, RMSE, IoA) is used to validate the model. RMSE for monthly results reduced from 7.94 ~ 24.91 mm/month to 7.94 ~ 24.91 mm/month for the validation period. The results confirmed that the accuracy was significantly improved compared to the existing Hargreaves equation. Further, the evaporative demand drought index (EDDI) based on the evaporative demand (E₀) was proposed. To confirm the effectiveness of the EDDI, this study evaluated the estimated EDDI for the recent drought events from 2014 to 2015 and 2018, along with precipitation and SPI. As a result of the evaluation of the Han-river watershed in 2018, the weekly EDDI increased to more than 2 and it was confirmed that EDDI more effectively detects the onset of drought caused by heatwaves. EDDI can be used as a drought index, particularly for heatwave-driven flash drought monitoring and along with SPI.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.687-700
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• 2022

For comprehensively assessment the water resources performance of multi-purpose dams and water supply dams in South Korea, a methodology was proposed to utilize the durational reliability along with the integrated auxiliary indicators including resiliency, dimensionless vulnerability, water resource efficiency, specific inflow, and specific water supply. In addition, for the purpose of sustainable dam operation in the future, a plan to grade the water resources performance was presented to periodically evaluate the performance and determine the priority of each dam's structural or non-structural planning according to the evaluation results. As major results, in the case of Sumjingang Dam, the durational reliability was 99.0%, but the integrated auxiliary index was the lowest of 44 points, which was 5th grade. This means that despite the current high reliability, hydrological changes due to future climate change or regional change of water demand-supply balance can have significant impacts on the water resources performances. In contrast, the Chungju Dam with a durational reliability of 93.0%, which is below the average among all multi-purpose dams, shows the 76 points of the integrated auxiliary index, which is 3^rd highest following the Soyanggang Dam and the Namgang Dam. Nevertheless, due to the size of the basin, the specific inflow is sufficiently high as 185%, so the actual performance could be evaluated relatively high. The water supply dams designed for a single purpose tend to be evaluated relatively high because they have a high proportion of industrial and municipal water supply and have enough room for the supply capacity.

• Journal of Korea Water Resources Association
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• v.56 no.6
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• pp.393-402
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• 2023

Drought, which has been increasing in frequency and magnitude due to recent abnormal weather events, poses severe challenges in various sectors. To address this issue, it is important to develop technologies for drought monitoring, forecasting, and response in order to implement effective measures and safeguard the ecological health of aquatic systems during water scarcity caused by drought. This study aimed to predict water quality fluctuations during drought periods by integrating the watershed model HSPF and the water quality model QUAL-MEV. The researchers examined the SPI and RCP 4.5 scenarios, and analyzed water quality changes based on flow rates by simulating them using the HSPF and QUAL-MEV models. The study found a strong correlation between water flow and water quality during the low flow. However, the relationship between precipitation and water quality was deemed insignificant. Moreover, the flow rate and SPI6 exhibited different trends. It was observed that the relationship with the mid- to long-term drought index was not significant when predicting changes in water quality influenced by drought. Therefore, to accurately assess the impact of drought on water quality, it is necessary to employ a short-term drought index and develop an evaluation method that considers fluctuations in flow.