Effect of National-Scale Afforestation on Forest Water Supply and Soil Loss in South Korea, 1971–2010

The Geostationary Ocean Color Imager (GOCI) of the Communication, Ocean, and Meteorological Satellite (COMS) increases the chance of acquiring images with greater clarity eight times a day and is equipped with spectral bands suitable for monitoring crop yield in the national scale with a spatial resolution of 500 m. The objectives of this study were to classify nationwide paddy fields and to project rice (Oryza sativa) yield and production using the grid-based GRAMI-rice model and GOCI satellite products over South Korea from 2011 to 2014. Solar insolation and temperatures were obtained from COMS and the Korea local analysis and prediction systems for model inputs, respectively. The paddy fields and transplanting dates were estimated by using Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance and land cover products. The crop model was calibrated using observed yield data in 11 counties and was applied to 62 counties in South Korea. The overall accuracies of the estimated paddy fields using MODIS data ranged from 89.5% to 90.2%. The simulated rice yields statistically agreed with the observed yields with mean errors of −0.07 to +0.10 ton ha−1, root-mean-square errors of 0.219 to 0.451 ton ha−1, and Nash–Sutcliffe efficiencies of 0.241 to 0.733 in four years, respectively. According to paired t-tests (α = 0.05), the simulated and observed rice yields were not significantly different. These results demonstrate the possible development of a crop information delivery system that can classify land cover, simulate crop yield, and monitor regional crop production on a national scale.

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Economic Dispatch Optimization of Multi-Water Resources: A Case Study of an Island in South Korea

Sustainability ◽

10.3390/su11215964 ◽

2019 ◽

Vol 11 (21) ◽

pp. 5964 ◽

Cited By ~ 1

Author(s):

Kapil Gnawali ◽

Kuk Heon Han ◽

Zong Woo Geem ◽

Kyung Soo Jun ◽

Kyung Taek Yum

Keyword(s):

Water Resources ◽

South Korea ◽

Water Supply ◽

Water Security ◽

Supply System ◽

Loss Of Function ◽

Security Issues ◽

Water Demands ◽

Self Sufficiency ◽

Sustainable Water Supply

Ensuring stable and continuous water supplies in isolated but populated areas, such as islands, where the water supply is highly dependent on external factors, is crucial. Sudden loss of function in the water supply system can have enormous social costs. To strengthen water security and to meet multiple water demands with marginal quality, the optimized selection of locally available, diversified multi-water resources is necessary. This study considers a sustainable water supply problem of Yeongjong Island, 30 km west from Seoul, South Korea. The self-sufficiency of several locally available water resources is calculated for four different scenarios based on the volume and quality of the various water sources. Our optimization results show that using all the available local sources can address the water security issues of the island in the case of interruption in the existing supply system, which is fed from a single source of mainland Korea. This optimization framework can be useful for areas where water must be secured in the event of emergency.

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Irrigation vulnerability assessment on agricultural water supply risk for adaptive management of climate change in South Korea

Agricultural Water Management ◽

10.1016/j.agwat.2015.01.012 ◽

2015 ◽

Vol 152 ◽

pp. 173-187 ◽

Cited By ~ 22

Author(s):

Won-Ho Nam ◽

Jin-Yong Choi ◽

Eun-Mi Hong

Keyword(s):

Climate Change ◽

South Korea ◽

Water Supply ◽

Adaptive Management ◽

Vulnerability Assessment ◽

Agricultural Water ◽

Supply Risk ◽

Agricultural Water Supply ◽

Water Supply Risk

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Smart Water Grid Research Group Project: An Introduction to the Smart Water Grid Living-Lab Demonstrative Operation in YeongJong Island, Korea

Sustainability ◽

10.3390/su13095325 ◽

2021 ◽

Vol 13 (9) ◽

pp. 5325

Author(s):

Kang-Min Koo ◽

Kuk-Heon Han ◽

Kyung-Soo Jun ◽

Gyumin Lee ◽

Kyung-Taek Yum

Keyword(s):

South Korea ◽

Water Supply ◽

Real Time ◽

Research Group ◽

Water Resource Management ◽

National Level ◽

Continuous Increase ◽

Smart Water ◽

Living Lab ◽

Smart Water Grid

In South Korea, in line with the increasing need for a reliable water supply following the continuous increase in water demand, the Smart Water Grid Research Group (SWGRG) was officially launched in 2012. With the vision of providing water welfare at a national level, SWGRG incorporated Information and Communications Technology in its water resource management, and built a living lab for the demonstrative operation of the Smart Water Grid (SWG). The living lab was built in Block 112 of YeongJong Island, Incheon, South Korea (area of 17.4 km2, population of 8000), where Incheon International Airport, a hub for Northeast Asia, is located. In this location, water is supplied through a single submarine pipeline, making the location optimal for responses to water crises and the construction of a water supply system during emergencies. From 2017 to 2019, ultrasonic wave type smart water meters and IEEE 802.15.4 Advanced Metering Infrastructure (AMI) networks were installed at 527 sites of 958 consumer areas in the living lab. Therefore, this study introduces the development of SWG core element technologies (Intelligent water source management and distribution system, Smart water distribution network planning/control/operation strategy establishment, AMI network and device development, Integrated management of bi-directional smart water information), and operation solutions (Smart water statistics information, Real-time demand-supply analysis, Decision support system, Real-time hydraulic pipeline network analysis, Smart DB management, and Water information mobile application) through a field operation and testing in the living lab.

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Hydro-Economic Water Allocation Model for Water Supply Risk Analysis: A Case Study of Namhan River Basin, South Korea

Sustainability ◽

10.3390/su13116005 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6005

Author(s):

Gimoon Jeong ◽

Doosun Kang

Keyword(s):

Climate Change ◽

South Korea ◽

Water Supply ◽

River Basin ◽

Water Allocation ◽

Economic Valuation ◽

Supply Risk ◽

Water Shortages ◽

Water Supply Risk

Rational water resource management is used to ensure a stable supply of water by predicting the supply of and demand for future water resources. However, rational water allocation will become more difficult in the future owing to the effects of climate change, causing water shortages and disputes. In this study, an advanced hydro-economic water allocation and management model (WAMM) was introduced by improving the optimization scheme employed in conventional models and incorporating the economic value of water. By relying upon economic valuation, the WAMM can support water allocation efforts that focus not only on the stability but also on the economic benefits of water supply. The water supply risk was evaluated following the different objective functions and optimization methods provided by the WAMM using a case study of the Namhan River basin in South Korea under a climate change scenario over the next 30 years. The water shortages and associated economic damage were compared, and the superior ability of WAMM to mitigate future water shortages using economic valuation and full-step linear programming (FSLP) optimization was demonstrated. It is expected that the WAMM can be applied to help resolve water shortages and disputes among river basin units under severe drought conditions.

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Evaluating and developing a model of specific degradation using geospatial analysis for sediment erosion management in South Korea

10.5194/hess-2021-225 ◽

2021 ◽

Author(s):

Woochul Kang ◽

Pierre Y. Julien

Keyword(s):

South Korea ◽

Soil Loss ◽

Large Scale ◽

Field Measurements ◽

Sediment Concentration ◽

Mean Annual Precipitation ◽

Sediment Delivery ◽

Rapid Urbanization ◽

Sediment Yields ◽

Specific Degradation

Abstract. The South Korean Peninsula is subject to hydrological extremes, and 70 % of its terrain is mountainous, with sharp ridges and steep valley flanks. Recently, rapid urbanization has created an emerging demand for large-scale water resources, such as dams and reservoirs. Accordingly, complicated sediment-related problems have become an issue, with abundant soil loss during typhoons transported to the reservoirs, and downstream, riverbed degradation is caused by intercepting sediment. Thus, a reliable approach is required for predicting sediment yields of soil erosion and sedimentation. In this study, the specific degradation (SD) of 62 stream-river watersheds and 14 reservoir watersheds were calculated from field measurements of sediment concentration and deposition. Estimated SD ranged between 10 and 1,500 tons·km−2·yr−1. Furthermore, existing empirical models of sediment yield are insufficient for predicting specific degradation upstream of the reservoirs; therefore, a new model was developed based on multiple regression analysis and model tree data mining of 47 watersheds (~75 % national land cover). Accuracy of the developed model was enhanced with the following significant parameters: (1) drainage area, (2) mean annual precipitation, (3) percent urbanized area, (4) percent water, (5) percent wetland and water, (6) percent sand at effective soil depths of 0–10 cm, (7) slope of the hypsometric curve, and (8) watershed minimum elevation. Additionally, erosion maps from the revised universal soil loss equation (RUSLE) were generated to validate model variables and further understand the sediment regime in South Korea. The gross erosion results for 16 ungauged watersheds were used to validate the empirical model by comparing sediment delivery ratios of other references. The modeled meaningful parameters were examined via remote sensing analyses of satellite and aerial imagery and revealed the features affecting erosion and sedimentation with an erosion loss map at 5-m resolution. Vulnerable areas of soil loss, including construction sites, and croplands, as well as sedimentation features, such as wetlands and agricultural reservoirs, were highlighted.

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Spatial Prediction of the Forest Soil Water Holding Capacities in Temperate Region on a National Scale With Random Forest Models

10.22541/au.162280786.69827193/v1 ◽

2021 ◽

Author(s):

Hyunje Yang ◽

Honggeun Lim ◽

Hyung Tae Choi

Keyword(s):

Random Forest ◽

South Korea ◽

Soil Properties ◽

Water Content ◽

Spatial Prediction ◽

Random Forest Model ◽

National Scale ◽

Environmental Covariates ◽

Forest Model ◽

Water Holding

Soil water holding capacities (SWHCs) is important input factor in hydrological simulation models for sustainable water management. Forests that covered 63% of South Korea are the main source of clean water, and it is essential to estimate SWHCs on a nationwide scale for effective forest water resources management. However, there are a few studies estimating SWHCs on a nationwide scale in the temperate regions especially in South Korea. Fortunately, forest spatial big data have been collected on a national scale, and the nationwide prediction of the SWHC can be possible with this dataset. In this study, spatial prediction of forest SWHCs (saturated water content, water content at pF1.8 and 2.7) was conducted with 953 forest soil samples and forest spatial big dataset. 4 soil properties and 14 environmental covariates were used for predicting SWHCs. Simple linear regression and random forest model were compared for selecting the optimal predictive model. From the variable importance analysis, environmental covariates had as big importance as soil properties had. And prediction performance of the model with environmental covariates as the input data was higher than that of the model with soil properties. Comparing two models, the random forest model could accurately and stably predict SWHCs than the simple linear model. As a result of spatial prediction of SWHCs at the national scale through the random forest model and the forest spatial big dataset, it was confirmed that higher SWHCs were distributed along with the Baekdudaegan, the watershed-crest-line in South Korea.

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