• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.4
• /
• pp.111-122
• /
• 1989

A multiple box model which is suitable for the prediction of water quality in shallow lakes with active mixing is a water quality model expected to be used widely in estuary reservoir. In this study, a multiple box water quality model for estuary reservoirs (MBQER) was developed arid the applicability of the MBQER was tested by applying data obtained from Asan-estuary reservoir. The results of this study can be summarized as follows. 1. The MBQER, dynamic water quality model, was developed to estimate 10-day water qualities of estuary reservoirs. For the proper analysis and the application of hydraulics needed to build a model, lake hydraulics was simplified by condisering only hydrological inflow and lake mixing currents. The box division in the MBQER is longitudinal one dimension for upper and middle part, and two layers for lower part of the reservoir. 2. The methods of box division for the multiple box model were ekamined and applied to Asan-estuary reservoir. For determining the number of boxes, Pe number and Pk number were used. In case of three boxes, the error by the model simplification would be estimated about 5 % Therefore, in Asan reservoir, the proper number of boxes was three. 3. The MBQER was calibrated and verified using measured data in Asan-estuary reservoir from 1986 to 1988. The Root Mean Squares(RMS) for the differences between measured data and simulated results by the MBQER were 1.10$^{\circ}$C C for water temperature, 75.8mg/1 for salinity, 0.082mg/1 for total-phosphorus showing good estimations. 4. Through the simulation of water temperature and salinity by the MBQER, the exchange flow and the mixing coefficients for the estuary lake were determined. As a result of simulation, the horizontal mixing coefficients in Asan-estuary reservoir were in the range of 1.07X 105 to 1.12X 105 cm$^2$/sec and vertical mixing coefficient was 2.90X 10-1 cm$^2$/sec.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.2 no.3 s.6
• /
• pp.109-117
• /
• 2002

An analysis to allocate storage space for sediment accumulation during the economic life of the reservoir is required in the planning or design of a reservoir. This analysis has been the most difficult and tedious aspect to deal with reservoir sedimentation because of the interaction between the various parameters related to the hydraulics of flow, reservoir operating policy, inflowing sediment load. The approach to analyzing spatial distribution of deposits has relied on empirical methods, all of which required a great deal of simplification from the actual physical phenomena. For the purpose of this study, reservoir sedimentation rate computed by Empirical Area Reduction Method is compared with measuring rate along the Soyang-gang Dam. As a conclusion, reservoir sedimentation rate can be estimated exactly by Empirical Area Reduction Method.

• Journal of Korean Society on Water Environment
• /
• v.23 no.5
• /
• pp.591-599
• /
• 2007

The quality of water released from a stratified reservoir is dependent on various factors such as the location and shape of intake facility, structure of reservoir stratification, profile of water quality constituent, and withdrawal flux. Sometimes, selective withdrawal capabilities can provide the operational flexibility to meet the water quality demands both in-reservoir and downstream. The objective of this study was to evaluate the performance of a one-dimensional reservoir selective withdrawal model (SELECT) as a tool for supporting downstream water quality management for Daecheong and Imha reservoirs. The simulated water quality variables including water temperature, dissolved oxygen (DO), conductivity, turbidity were compared with the field data measured in tailwater. The model showed fairly satisfactory results and high reliability in simulating observations. The coefficients of determinant between simulated and observed turbidity values were 0.93 and 0.95 for Daecheong and Imha reservoirs, respectively. The outflow water quality was significantly influenced by water intake level under fully stratified condition, while the effect of intake amount was minor. In conclusion, the SELECT is simple but effective tool for supporting downstream water quality prediction and management for both reservoirs.

• Journal of the Korean GEO-environmental Society
• /
• v.21 no.9
• /
• pp.5-14
• /
• 2020

This study analyzed the reinforcement effect by conducting laboratory test, model test and program analysis to utilize the surface stabilizer used for the restoration work of collapsed slopes as a reinforcing material for aging reservoirs that exhibits a curing reaction similar to cement. Based on the results of the laboratory test, a model test and program analysis were performed by applying 9% of the mixing ratio. As a result, when the surface stabilizer was used in aging reservoir, it was found that the flow of water only occurred on part of the slope and underground in reservoir. And the water flow could be reduced inside the reservoir. In addition, it was analyzed that the seepage discharge could be reduced by about 42% and the saturated area within the reservoir by about 73%, thereby securing the stability of the aged reservoir.

• Journal of Korean Society on Water Environment
• /
• v.25 no.6
• /
• pp.821-831
• /
• 2009

The study was aimed to assess the expected impact of climate change on the water cycle and soil losses in Daecheong Reservoir watershed, Korea using the Soil and Water Assessment Tool (SWAT) that was validated for the watershed in a previous study. Future climate data including precipitation, temperature and humidity generated by introducing a regional climate model (Mesoscale Model Version 5, MM5) to dynamically downscale global circulation model (European Centre Hamburg Model Version 4, ECHAM4) were used to simulate the hydrological responses and soil erosion processes in the future 100 years (2001~2100) under the Special Report on Emissions Scenario (SRES) A1B. The results indicated that the climate change may increase in the amount of surface runoff and thereby sediment load to the reservoir. Spatially, the impact was relatively more significant in the subbasin Bocheongcheon because of its lower occupation rate of forest land compared to other subbasins. Seasonally, the increase of surface runoff and soil losses was more significant during late summer and fall season when both flood control and turbidity flow control are necessary for the reservoir and downstream. The occurrence of extreme turbidity flow events during these period is more vulnerable to reservoir operation because the suspended solids that remained water column can be resuspended by vertical mixing during winter turnover period. The study results provide useful information for the development of adaptive management strategy for the reservoir to cope with the expected impact of future climate change.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.11a
• /
• pp.33-45
• /
• 2006

The interest of sediment has been increased daily because most of domestic dam reservoir's operation time have been extended and wide basin area is the main characteristics for artificial reservoir which the speed of water flow in artificial reservoir is slower than that of natural reservoir. Therefore a lot of sediment has been significantly accumulated. In this study, the accurate topographic data were obtained using echo-sounding system. GPS survey, low-frequency sub-bottom profiler, and high-frequency echo-sounding system were used to compute the exact amount of sediment. Based on the results, DEM(Digital Elevation Model) and DSM(Digital Surface Model) were generated. The GIS system for the management of sediment was created based on topographic data on the riverbed and this system can be efficiently used for the management of sediment which caused the problems of reservoir capacity and water quality.

• Journal of Korean Society on Water Environment
• /
• v.30 no.5
• /
• pp.491-502
• /
• 2014

As meteorology is the driving force for lake thermodynamics and mixing processes, the effects of climate change on the physical limnology and associated ecosystem are emerging issues. The potential impacts of climate change on the physical features of a reservoir include the heat budget and thermodynamic balance across the air-water interface, formation and stability of the thermal stratification, and the timing of turn over. In addition, the changed physical processes may result in alteration of materials and energy flow because the biogeochemical processes of a stratified waterbody is strongly associated with the thermal stability. In this study, a novel modeling framework that consists of an artificial neural network (ANN), a watershed model (SWAT), a reservoir operation model(HEC-ResSim) and a hydrodynamic and water quality model (CE-QUAL-W2) is developed for projecting the effects of climate change on the reservoir water temperature and thermal stability. The results showed that increasing air temperature will cause higher epilimnion temperatures, earlier and more persistent thermal stratification, and increased thermal stability in the future. The Schmidt stability index used to evaluate the stratification strength showed tendency to increase, implying that the climate change may have considerable impacts on the water quality and ecosystem through changing the vertical mixing characteristics of the reservoir.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.62 no.5
• /
• pp.73-84
• /
• 2020

In this study, we compared and analyzed the static and dynamic analysis method for agricultural reservoirs. In addition, we assumed the aging of reservoir as the deterioration of the internal friction angle and cohesion. The internal friction angle and cohesion were applied by dividing into 4 case for each reservoir. As a result of comparing the stability of the reservoir embankment, it was found that the dynamic stability analysis method showed a greater risk than the static stability analysis method when dynamic loads such as earthquakes were applied. Therefore, when detailed review such as liquefaction is required, it is considered that the dynamic stability analysis method should be applied first. If a study on the change in material properties due to the aging of the reservoir is conducted, the stability analysis of the reservoir due to the aging of the reservoir can be performed more accurately. In addition, if a study comparing the results of dynamic stability analysis and static stability analysis for earthquakes with various characteristics for more reservoirs is conducted, detailed criteria for the case where dynamic stability analysis should be considered can be presented.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.13 no.2 s.29
• /
• pp.127-132
• /
• 2007

This study is to determine an optimal reservoir among many alternative proposals in order to obtain the maximized efficiency under the limited budget. There are many alternative proposals which deal with problems to assign reservoir such as water conversion establishment construction, subterranean water, reservoir, submarine pipeline, water boat, and marine water saving base construction. In this paper, the new model to assign the most reasonable alternative is introduced using 0-1 integer programming. This proposed model has not been applied in the optimal reservoir selection problem yet. This paper will contribute to determine the most reasonable alternative to minimize budget under constraints. Also, this proposal model can be applied to other reservoir selection problem in other regions.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.60 no.1
• /
• pp.1-10
• /
• 2018

This study analyzed pore water pressure, seepage and leakage quantity, height of seepage and critical hydraulic gradient in order to suggest the seepage characteristics of agricultural reservoir embankment considering filter interval. The seepage characteristics of a deteriorated reservoir embankments were conducted according to the horizontal filter intervals range using three- dimensional finite element analysis. The wider the horizontal filter interval, the higher the pore water pressure increased, and the pore water pressure ratio in the center of the core has a greater effect than the base part. The seepage and leakage quantity appeared largely in the two-dimensional analysis conditions (case 1), where the filter was constructed totally in the longitudinal direction of the embankment, the wider the horizontal filter interval was gradually reduced. The reasonable filter intervals to yield efficient seepage characteristics were within 30 m for the pore water pressure of the core and the height of the seepage line. The stability of the filter installation was able to evaluate the stability of the piping by the critical hydraulic gradient method. The deteriorated reservoir with no filters or decreased functionality can significantly reduce the possibility of piping by simply installing a filter on the downstream slope. In the future, the deteriorated reservoir embankment should be checked for the reservoir remodeling because the core and filter functions have been lost or decreased significantly. In the case of a new installation, the seepage characteristic behavior due to the core and filter changes should be applied to the field after obtaining a reasonable horizontal filter interval that satisfies the safety factor by a three-dimensional analysis.