• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.04a
• /
• pp.338-341
• /
• 2002

This work is the basis research to apply Hydrocyclone for the separation and the thickening to the reservoir sediment. Chemical analysis result showed that organic contaminants were abundantly found in smaller sediment particles. As a result of the experiment device that higher reduced efficiency was obtained under the high velocity and low concentration with the small cyclones.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.39 no.3
• /
• pp.115-127
• /
• 1997

Nonpoint source (NPS) pollution from small watersheds has recently been brought into attention as a potential pollutant to streams and tnbutaries, as majority of them are experiencing water quality degradation. This necessiates the quantification of NPS loadings from agricultural and forested lands. And this study attempts to quantify daily loadings from forested and farm lands using hydrologic and water quality monitoring. The hydrologic monitoring program consists of five water level gauging stations along creeks and stream at the Banweol reservoir watershed having 1220 hectare in size. Water sam pies were taken and analyzeel periodically at the streamf low gaging sites and tributaries. Soil samples were also taken and the chemical constitutes analyzed. The primary results indicate that the major sources of pollution were small villages and dairy farms on the watersheds, constituting two-third of total nutrient loadings to the reservoir. However, the loadings from paddies and upland areas may cause a problem to the water quality of the reservoir and stream as the measured levels of total nitrogen and phosporus are not low enough to ignore. Further studies are needed to quantify the effects of landuses and treatments at a watershed scale.

• ALGAE
• /
• v.19 no.2
• /
• pp.115-122
• /
• 2004

The epilithic algal communities on the artificial substrata (unglazed ceramic tiles) were investigated from 5th July to 24th July 1999 with two or three days intervals for elucidating the effects of the experimental acidification. They were harvested inside the mesocosm with and without the acid treatment on Togyo reservoir within the Civilian Passage Restriction Line near Demilitarized Zone (DMZ) in Korea. After the colonization of epilithic algal community, their standing crops revealed different patterns outside and inside the mesocosm. However the time lapse of 5 days was observed on the inside with acid treatment. The dominant species were different: Achnanthes minutissima was outside but Coenochloris polycocca was inside and inside with acid treatment. The differences in floral composition were also found. Achnanthes minutissima which has been the most important species in the colonization by the epilithic algal community of the mesocosm was less important at the lower pH. Coenochloris polycocca is a species well adapted to low pH.

• Land and Housing Review
• /
• v.5 no.3
• /
• pp.203-214
• /
• 2014

The purpose of this paper is to introduce two integrated urban development projects in Japan that take full advantage of flood-control reservoirs: the Tetsugakudo Park Collective Housing Development Project and the Koshigaya Lake Town Project. The former project - implemented cooperatively by the Tokyo metropolitan government in charge of river management, Shinjuku and Nakano wards (in Tokyo) responsible for park management, and the Urban Renaissance Agency, a housing project developer - set a significant precedent for three-dimensional river use by realizing the three-dimensional integrated development of a flood control reservoir, a park, and collective housing. The Koshigaya Lake Town Project, launched as a drastic storm water management measure for a low-lying area often plagued by flooding, has achieved a sustainable coexistence between the waterfront environment and the urban living environment, with an artificial flood-control reservoir as the core for urban development. This project is fully committed to environmental coexistence through the optimal use of local environmental resources, with the cooperation of the central government, Saitama Prefecture and Koshigaya City.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.30 no.1
• /
• pp.50-62
• /
• 1988

This study refers to the development of a hydrologic model simulating daily inflow and release rates for irrigation reservoirs. A daily - based model is needed for adequate operation of an irrigation reservoir sufficing the water demand for paddy fields which is closely related to meteorological conditions. Inflow rates to a reservoir need to be accurately described, which may be simulated using a hydrologic model from daily rainfall data. And the objective of this paper is to develop, test, and apply a hydrologic model for daily runoff simmulation. A well - known tank model was selected and modified to simulate daily inflow rates. The model parameters were calibrated using observed runoff data from twelve watersheds, Relationships between the parameters and the watershed characteristics were derived by a multiple regression analysis. The simulation results were in agreement with the data. The inflow model was found to simulate low flow conditions more accurately than high flow conditions, which may be adequate for water resources utilization.

• Journal of Ecology and Environment
• /
• v.43 no.2
• /
• pp.271-281
• /
• 2019

Background: The plant communities within reservoir drawdown zones are ecologically important as they provide a range of ecosystem services such as stabilizing the shoreline, improving water quality, enhancing biodiversity, and mitigating climate change. The aim of the study was therefore to identify the major environmental factors affecting these plant communities within the drawdown zone of the Soyangho Reservoir in South Korea, which experiences a monsoonal climate, and thereafter to (1) elucidate the plant species responses and (2) compare the soil seedbank composition along main environmental gradients. Results: Two main environmental gradients affecting the plant community structure were identified within the drawdown zone; these were a vertical and longitudinal gradient. On the vertical dimension, a hydrological gradient of flood/exposure, the annual-dominated plant community near the water edge changed to a perennial-dominated community at the highest elevation. On the longitudinal dimension from the dam to the upstream, plant species composition changed from an upland forest-edge community to a lowland riverine community, and this was correlated with slope degree, soil particle size, and soil moisture content. Simultaneously, the composition of the soil seedbank was separated along the vertical gradient of the drawdown zone, with mainly annuals near the water edge and some perennials at higher elevations. The species composition similarity between the seedbank and extant vegetation was greater in the annual communities at low elevation than in the perennial communities at higher elevation. Conclusions: The structures of plant community and soil seedbank in the drawdown zone of a monsoonal riverine reservoir were changed first along the vertical and secondly along the longitudinal gradients. The soil seedbank could play an important role on the vegetation regeneration after the disturbances of flood/exposure in the drawdown zone. These results indicate that it is important to understand the vertical and longitudinal environmental gradients affecting shoreline plant community structure and the role of soil seedbanks on the rapid vegetation regeneration for conserving and restoring the drawdown zone of a monsoonal reservoir.

• Journal of Korean Society on Water Environment
• /
• v.38 no.6
• /
• pp.275-281
• /
• 2022

To maintain water quality after water treatment, monitoring whether the quality of treated tap water quality changes is essential. However, current investigations are insufficient to prevent secondary contamination in drinking water supply systems. This study investigated Gyeonggi's e apartment where a red water problem occurred and monitored the water quality and corrosiveness of the overall water supply system to the apartment from June 2021 to April 2022. In a comparison of drinking water quality after water treatment and the influent of the reservoir, turbidity and heavy metal concentrations were increased and residual chlorine was decreased due to increases in temperature. Correlation analysis and principal component analysis (PCA) indicated that a low level of residual chlorine may cause the abscission of Mn²⁺ and Fe²⁺ through microorganism activation, which also causes a high level of turbidity. The corrosion index (LI) in the influent of the reservoir tank was increased due to Ca²⁺ and temperature. These results indicate that the corrosiveness of drinking water and the deterioration of drinking water quality were mainly increased between the drinking water treatment plant and the reservoir tank's influent. The findings provide clear evidence that it is essential to manage water supply systems and reservoir tanks to prevent the secondary contamination of drinking water.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.44-51
• /
• 2005

Water flow in rivers during flood season can be 10 to 100 fold higher than normal seasons (low precipitation) in Japan and predicting flood runoff is essential for operating reservoirs with discharging gates. Abundant experiences and knowledge are requisites for operators to be able to make efficient decisions at work. This research investigated a method to transfer technical knowledge by acquiring skills and knowledge from actual dam operators and by using the information to construct an educational training system. The purpose of the research was to enable the execution of a secure and rational reservoir operation during flood period. The educational training system for reservoir operation was developed with the focuses on acquiring knowledge on hydraulics and hydrology and learning about decision making related to the reservoir operation as well as the timing of control. The system is capable of conducting education that corresponds to individual levels in each location. Of the educational training methods, a lecture method that uses textbooks is effective for the understanding of basic knowledge and concepts while a training method that uses a simulation device is essential for the practice of advanced and specialized procedures in specific fields. Simulation devices are used in operational training for airplane flight and driving cars and trains. The educational system presented here was designed to provide further assistance to those who have acquired basic knowledge and concepts through textbooks and also to at low them to perform the satisfactory operation of dam equipment. Our research proposes a method which can realize a system to acquire technical skills-the skills which are the foundation of technical knowledge and operation.

• Journal of Environmental Impact Assessment
• /
• v.19 no.3
• /
• pp.215-222
• /
• 2010

This research aims to gain the result of assessment of inflow categorized by runoff path using DIROM (Daily Irrigation Reservoir Operation Model) for Baengnyeong-myeon reservior which was built for residents of Baengnyeong island to solve the shortage of drinking water and stable supply of domestic water. The simulation results of DIROM and actual hydrograph of the reservoir show very low correlation with geological characteristics. The simulation results by DIROM after adjusting with modified Tank III model which considers all outflow from Tank II model as interflow among 3 level tanks show good correlation of its regional runoff and inflow characteristics with $R^2$=0.9058. In the study area, diffluence of 37% of rain fall of the study year has been simulated, which shows low result compared to the average river runoff of national water resource. In addition, 34.5% of total inflow to the study reservoir is mainly interflow and baseflow among expected several channels.

• Korean Journal of Ecology and Environment
• /
• v.37 no.3 s.108
• /
• pp.272-281
• /
• 2004

The Primary production and budget of organic carbon at rainy and dry period was surveyed to evaluate the contribution of primary production in Paldang Reservoir. Primary productivity of phytoplankton showed remarkable differences depending on sampling dates and sites, ranged from 110 to 2,701 mgC $m^{-2}day^{-1}$. In the rainy period of April and August when there had been frequent rainfall resulting short hydraulic retention time and low algal biomass in Paldang Reservoir, autochthonous organic carbon occupied very low ratio, farming approximately 7 percent of total inflow of organic carbon. However in June when it almost never rained and dominant algal species changed from diatoms to green algae and small flagellates, autochthonous organic carbon from primary productivity of phytoplankton formed 29 percent of total inflow of organic carbon.