• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.535-542
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• 2017

There is a big difference of discharge rate between drought and flood period in Korea since the importance of water resources management has come to the fore. To know a river characteristics, it needs to estimate river discharge accurately. River discharge is calculated using the measured velocity of cross section and the estimated area of watercourse as input parameters into continuity equation. Generally, flow rate over a river is estimated from the relation equation between level and discharge, in this case, there are weakness for only the equal depths and the equal discharge estimated. In the present study, therefore, water surface slope was estimated using measured water level of Seongseo water level observation station and measured water level using ADVM at Gangchang Bridge. And then, we developed the discharge calculation equation using water surface slope. A method to easily calculated flow rate from the measured depth of the two points that are suggested by reflecting water surface slope because natural stream is unsteady flow, not uniform flow or not steady flow.

• Journal of Korean Society of Rural Planning
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• v.24 no.2
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• pp.109-114
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• 2018

In this study, we estimate the greenhouse farmers' willingness to pay of agricultural water supply through pipeline. First, in the questionnaire design, orthogonal design and block design were used to enhance the ease of survey. Second, the theoretical model was constructed through the setting of the probability utility function, and the parameters were estimated by using the conditional logit model. Third, all of the estimation coefficients were statistically significant at the 1% significance level. The results of analysis are summarized as follows. First, the probability of selection is increased when maintenance is carried out by Korea Rural Community Corporation or local government. Second, the probability of selection is increased when agricultural water supply through pipeline is higher than the current level. Third, if the Korea Rural Community Corporation carries out maintenance management, the marginal willingness to pay is 44 won per ton. And if the local government carries out maintenance management, the marginal willingness to pay is 25 won per ton. Fourth, according to the quality level of agricultural water supply, the marginal willingness to pay is 101 won, 114 won and 120 won per ton, respectively. This study can be used as a basic data on the cost setting for agricultural water supply through pipeline.

• Journal of Korea Water Resources Association
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• v.56 no.5
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• pp.357-362
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• 2023

The conflict between upstream and downstream regions is a representative social conflict in Korea. It is important issues in the economic and environmental aspects related to interests of property rights and water quality conservation. however, it is insufficient for studies on the economic damage and benefits between upstream and downstream by policy. We studied validity for drinking water protect zone, one of the major water conflict in Korea, by comparison between social loss by property rights restriction in the upstream and social benefits in the downstream and we proposed integrated water management policy in basin level.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.3
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• pp.162-171
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• 2014

In this study, the uncertainty analysis of present land pollutant load estimation with simplified land category in TMDLs was performed and the enhanced method for land pollutant load estimation with level II land cover consisting of 23 categories was suggested, which was verified by L-THIA model. For land TP load estimation in Jinwi stream basin, the result of comparison between existing method with simplified land category (Scenario 1) and enhanced method with level II land cover (Scenario 2) showed high uncertainty in existing method. TP loads estimated by Scenario 2 for land covers included in the site land category were in the range of 3.45 to 56.69 kg/day, in which TP loads differed by sixteen times as much among them. For application of scenario 2 to TMDLs, Land TP loads were estimated by matching level II land cover to 28 land categories in serial cadastral map (Scenario 3). In order to verify accuracy of TP load estimation by scenario 3, the simulation result of L-THIA was compared with that and the difference between the two was as little as 10%. The result of this study is expected to be used as primary data for accurate estimation of land pollutant load in TMDLs.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2004.11a
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• pp.76-76
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• 2004

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.245-254
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• 2020

Water quality improvement projects are being implemented without predicting the effect of water quality improvement on Lake Sapgyo. As the method of selecting the target stream for the effective conduct of water quality improvement projects the method of rating the streams were studied. To build a stream grading method, 60 major streams in the Lake Sapgyo system were monitored. The selection method of rivers subject to priority management for water quality improvement was applied to the stream grading method using the Analytic Hierarchy Process (AHP). The analysis of importance by site by stream grading method revealed the following: water quality (36.0%), flow (26.1%), travel load (13.4%), TMDL density (12.0%), TMDL (8.9%), and area (3.7%). The pollution level of the river was scored by using the stream grading method, and the ranking of 51 streams was calculated. Based on this, the group was classified into six grades (A-F). Among the groups, the F and E groups were selected as the priority management streams. Cheonan-Cheon (Cheonan City) was selected as the first stream to establish water quality improvement measures in the Lake Sapgyo system, and Seowoo-Cheon (Dangjin City) was selected as the second site, and Oncheon-Cheon (Asan City) was selected as the third site. Each local government is expected to improve the water quality improvement effect with limited resources when establishing and implementing water quality improvement measures for the streams (F group, E group) to be managed in this study.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.619-629
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• 2020

The National Groundwater Monitoring Network (NGMN) in South Korea has been implemented in alluvial/ bedrock aquifers for efficient management of groundwater resources. In this study, aquifer types were reclassified with unconfined and confined aquifers based on water-level fluctuation and water quality characteristics. Principal component analysis (PCA) of water-level data from paired monitoring wells of alluvial/bedrock aquifers results in the principal components of both aquifers showing similar water-level fluctuation pattern. There was no significant difference in the rate of water-level rises responding to precipitations and in the NO₃-N concentrations between the alluvial and bedrock aquifers. In contrast, in the results classified with the hydrogeological type, the principal components of water level were different between unconfined and confined conditions. The water-level rises to precipitation events were estimated to be 4.6 (R²=0.8) in the unconfined and 2.1 (R²=0.4) in the confined aquifers, respectively, indicating less impact of precipitation recharge to the confined aquifer. The confined aquifers have the average NO₃-N concentration below 3 mg/L, implying the natural background level protected from the sources at surface. In summary, reclassification of aquifers into hydrogeological types clearly shows the differences between unconfined and confined aquifers in the water-level fluctuation pattern and NO₃-N concentrations. The hydrogeologic condition of aquifer could improve groundwater resource management by providing critical information on groundwater quantity through recharge estimation and quality for protection from potential contamination sources.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.933-937
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• 2010

This study aimed at the introduction of desktop method for assessment of environmental flows developed by IWMI(International Water Management Institute) recently and its application to Geum river basin. This scheme simulated the influence on aquatic ecosystem caused by watershed development and in turn the decrease of water quantity keeping the river's own flow regime. It was found to be as very effective method although it had simple structure. Flow duration curves for different environmental classes at Sutong and Gongjoo sites were estimated according to the natural conditional scenario of Geum river basin and the results were relatively compared well with the previous studies. The behaviors of monthly average runoff time series of both sites showed the level of A class. The results of this study would provide the fundamental data to establish the future plans of monitoring or management for aquatic ecosystem of Geum river basin.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.445-452
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• 2020

Tributary is a part of life space for people and a very important place that accommodates rest recreation and other daily activities. absolutely insufficient basic data about water quality and flow rate are available for basin management. Efficient water and basin management systems, which are also supported by local residents can be established by securing such basic data of major tributaries in the Nakdong river system. In this study, the fluctuation characteristics of upstream and downstream water pollution levels were compared using the measurement results of the water environment measurement network and the tributary monitoring project for the gyeseong-stream and Hwapo-stream in the Nakdong-miryang watershed. In 2017, when water pollution is the highest, it was confirmed that the annual average rainfall was the lowest. Although the upstream and downstream water quality tendencies of the Gyeseong-stream are similar, the water quality concentrations of the Gyeseong-stream are relatively different. But although the Hwapo stream has various causes of pollution, there was not much difference in the level of pollution between the upper and lower streams. In addition, both rivers need the ability to purify rivers by securing sufficient water for river maintenance, and if the correlation between water quality items can be inferred through continuous monitoring of tributaries where the aspect of water quality change is unclear, water quality management Determined to be efficient operation.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.79-88
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• 2019

In order to study the water quality status and its causal environmental factors, the water quality variables of chemical oxygen demand (COD), chlorophyll a (Chl a), Total phosphorus (TP), and total nitrogen (TN), the hydrogeomorphologic variables of water level fluctuation, total water storage, dam elevation, watershed area, and shoreline development index, and the land cover variables of forest, agricultural area, and urbanized area in the watershed were investigated in total 73 reservoirs with various operational purposes, water level fluctuation and geographical distribution in South Korea. The water quality was more eutrophic in the reservoirs of the more urbanized and agricultural area in the watershed, the low altitude, the narrow water level fluctuation, the narrowed watershed area, and the more circular shape. In terms of the purposes of reservoir operation, the reservoirs for agricultural irrigation were more eutrophic than the reservoirs for flood control. The results of the variable selection and path analysis showed that COD determined by Chl a and TP was directly affected by water level fluctuation and the shoreline development of the reservoirs. TP was directly affected by the urbanized area of the watershed which was related to the elevation of the reservoir. TP was also influenced by the water level fluctuation and the shoreline development. In conclusion, the eutrophication of the reservoirs in Korea would be influenced by the land use of the watershed, hydrological and geographical characteristics of the reservoir, water level fluctuation by the anthropogenic management according to the reservoir operation purpose, and the location of the reservoirs.