• Journal of Soil and Groundwater Environment
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• v.26 no.1
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• pp.65-75
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• 2021

We investigated hydrochemical and stable isotope characteristics of groundwater in a large agricultural plain, the Honam plain, to evaluate the adequacy of agricultural water supply. For preliminary assessment for the area, we collected 23 groundwater samples from domestic wells and conducted hydrochemical and water stable isotope analysis. Groundwater in the study area is mainly Ca-HCO3 type resulting from water-rock interactions. Stable oxygen and hydrogen isotopic compositions indicated that recharge water is derived from precipitation while some sampling sites had evaporation signatures. Irrigation water quality using sodium absorption ratio and salinity hazard showed most of the groundwater samples were found to be suitable for irrigation. The groundwater in the southwestern part of the study area was affected by both seawater intrusion and agricultural activities, indicating a higher possibility of groundwater contamination near the coastal areas. Elevated concentrations of nitrate and phosphate ions in the groundwater are considered to be influenced by anthropogenic activities such as fertilizer application. It is expected that this study would be able to provide preliminary information on groundwater quality for agricultural water supply in the Mangyeong-Dongjin watershed.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.21-27
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• 2013

The present study explored the way to desalinate seawater for agricultural irrigation using forward osmosis (FO) process using liquid fertilizer as draw solution. FO experiments were performed in a cross flow mode using flat sheet FO membrane. The effect of membrane orientation, flow rate, and draw solution concentration on the performance of forward osmosis was investigated by measuring water flux of forward osmosis membrane. The water flux when the draw solution was placed against the membrane active layer was lower than the water flux when the feed solution was placed against the membrane active layer. This results indicated that the decrease of effective osmotic pressure by dilutive internal concentration polarization was less than that by concentrative internal concentration polarization. Increasing flow rate from 66.7 to 133.1 $cm^3$/min resulted in increase of the water flux when the membrane active layer orient to draw solution and feed solution, respectively. The reduction of resistance to water flow increased water flux at higher flow rate. The water flux of FO membrane increased with increasing draw solution concentration from 10000 to 30000 mg/L. The water flux for $KH_2PO_4$ draw solution was similar to that for commercial fertilizer. Optimization of FO process would contribute to economically desalinate brackish water for agricultural use.

• Membrane and Water Treatment
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• v.4 no.2
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• pp.95-108
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• 2013

Metal ions exist in seawater, groundwater and industrial wastewaters. These source waters can be recycled if their concentrations are reduced. A number of processes can be applied for this purpose. Liquid-liquid extraction is one of the promising methods. In this paper, experimental results are presented on the removal of Cr(VI) using Aliquat-336, a reactive carrier, in sunflower oil (a non-toxic solvent). The performance of this new system is compared with those of kerosene (a toxic solvent). The extent of removal of Cr(VI) from samples with high and low concentrations are presented. The process was upgraded to a bench-scale module that can selectively remove about 50-90% Cr(VI) from samples of groundwater. Thus this process can produce water within the acceptable range for recycling and for use in secondary purposes such as irrigation.

• KCID journal
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• v.18 no.1
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• pp.44-57
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• 2011

The status of fishway installed in domestic dikes showed a cascade types and sluice gate types 36% (four sites) and 64% (seven sites), respectively. Fishway of cascade type was constructed four sites (Iweon, Busa, Geum river, Haenam) and only Geum river was one of them has operated much more effectively since remodeling in a fishway and fishways of the others was not operated because of several problems like a desalination, a shortage of inflow water and variation of management elevation. Fishway of sluice gate type was installed seven sites and three sites (Yeongsan, Yeongam, Geumho) one of them were continuously operated until now. This results has a interesting interpretations. Prolonged discharge of inductive water from fishway can positively affect not only ascending of fishes but also fish fauna of around of the sea. The others of a sluice gate fishway were not operated because of seawater circulation through sluice gate until now. The closed reasons of fishway in domestic dikes may be summarized as follows: impassibility of sluice gate open by shortage of inflow water, problem of proper operating by long distance of between fishway and management office, absence of operating manual, seawater circulation, lack of fishway operating awareness. It was takes a long time for solution of hardware part but software part can be to find the answer through making a fishway operation manual and development of education program for manager. In this paper we deal with fishway in domestic dikes. Proper fishway control by manager was essential for ascending of migration fishes especially at fishway installed in dikes. Thus it was necessary to make manual for fishway operation and effort of continuously maintenance.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.1-11
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• 2014

Rural groundwater monitoring network has been managed by Korea Rural Community Corporation (KRC) since 1998. The network consists of two kinds of subnetworks; rural groundwater management network (RGMN) and seawater intrusion monitoring network (SIMN). RGMN has been operated to promote a sound and sustainable development of rural groundwater within the concerned area for groundwater quality and quantity. SIMN has been operated to protect the crops against hazards by the saline water in coastal areas in which the shortage of irrigation water become a main problem for agriculture. Currently, a total of 283 monitoring wells has been installed; 147 wells in 79 municipalities for RGMN and 136 wells in 52 ones for SIMN, respectively. Two subnetworks commonly monitor three hydrophysical properties (groundwater level, temperature, and electric conductivity) every hour. Monitored data are automatically transferred to the management center located in KRC. Data are opened to the public throughout website named to be the Rural Groundwater Net (www.groundwater.or.kr). Annual reports involving well logging and hydrochemical data of RGMN and SIMN have been published and distributed to the rural water management office of each municipalities. In addition, anyone who concerns about RGMN an SIMN can freely download these reports throughout the Rural Groundwater Net as well.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.663-664
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• 2016

Temperature difference power generation using sea water is a method repeatedly closed liquefaction and gasification by using the ammonia (refrigerant) of the deep sea water and surface water with a temperature difference between turning the turbine. The larger the temperature difference between the nature of the temperature characteristic energy generation development, the better. This is the story that the surface waters of the deep-water temperature difference is large. But the winter is not large temperature difference between surface water and deep water has lowered energy efficiency. And desalination technologies accounted for 97% of the earth, but we can not eat the technology to convert sea water into fresh water, fresh water produced by the desalination technology that is available for various industries such as irrigation, drinking water in the vessel.In this paper, LNG transport vessels, based on the LNG transport ship to the temperature difference power generation using cold energy of thermal energy and LNG marine diesel engines, which use the existing order to improve the temperature of the surface waters of the season that is the current problem we propose that a complex development of desalination and desalination of seawater freezing research into hybrid research and utilizing the cold energy of the engine.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.40-48
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• 2008

The Waimea Basin is located on the northern tip of the South Island of New Zealand. It is a highly productive area with intense water use with multi-stakeholder interest in water. Irrigation from the underground aquifers here makes up the largest portion of used water; however the same aquifers are also the key urban and industrial sources of water. The Waimea/Wairoa Rivers are the main sources of recharge to the underlying aquifers and also feed the costal springs that highly valued by the community and iwi. Due to the location of the main rivers and springs close to the urban centre the water resource system here has high community and aesthetic values. Recent enhanced hydrological modelling work has shown the water resources in this area to be over allocated by 22% for a 1:10 year drought security for maintaining a minimalistic flow of 250 l/s in the lower Waimea River. The current irrigated land area is about 3700 hectares with an additional potential for irrigation of 1500 hectares. Further pressures are also coming on-line with significant population growth in the region. Recent droughts have resulted in significant water use cutbacks and the threat of seawater intrusion in the coastal margins. The Waimea Water Augmentation Committee (WWAC) initiated a three year stage 1 feasibility study in 2004/2005 into the viability of water storage in the upper parts of the catchment for enhancing water availability and its security of supply for consumptive, environmental, community and aesthetic benefits downstream. The project also sought to future proof water supply needs for the Waimea Plains and the surrounding areas for a 50 - 100 year planning horizon. The broad range stage 1 investigation programme has identified the Upper Lee Catchment as being suitable for a storage structure to provide the needs identified and also a possibility for some small scale hydro electricity generation as well. The stage 2 detailed feasibility investigations that are underway now (2007/2008), and to be completed in two years is to provide all details for progressing with the next stage of obtaining necessary permits for construction and commissioning a suitable dam.

• Economic and Environmental Geology
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• v.42 no.6
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• pp.575-589
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• 2009

Groundwater has been extracted for irrigation in Sacheon-Hadong area, which is close to the South Sea. We analyzed chemical components of groundwater to examine the effects of seawater intrusion and agricultural activities in the study area. Most groundwater samples displayed the Na/Cl concentration ratios similar to that of seawater (0.55) with an increasing tendency of electrical conductivity ($227-7,910\;{\mu}S/cm$) towards the coast. In addition, statistical interpretation of the cumulative frequency curves of Cl and $HCO_3$ showed that 30.1% of the groundwater samples were highly affected by seawater intrusion. Groundwaters in the study area mostly belonged to the Ca-Cl and Na-Cl type, demonstrating that they were highly influenced by seawater intrusion and cation exchange. The result of oxygen-hydrogen isotope analysis demonstrated slightly higher $\delta^{18}O$ ((-8.53)-(-6.13)‰) and ${\delta}D$ ((-58.7)-(-43.7)‰) comparing to mean oxygen-hydrogen isotope ratios in Korea. As a result of nitrogen isotope analysis, the $\delta^{15}N-NO_3$ values ((-0.5)-(19.1)‰) indicate two major sources of nitrate pollution (organic nitrogen in soil and animal and human wastes) and mixed source of the two. However, denitrification may partly contribute as a source of nitrogen. According to factor analysis, four factors were identified among which factor 1 with an eigenvalue of 6.21 reflected the influence of seawater intrusion. Cluster analysis indicated the classification of groundwater into fresh, saline, and mixed ones.

• Geophysics and Geophysical Exploration
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• v.5 no.4
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• pp.257-261
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• 2002

We have carried out integrated research including field survey and numerical modeling to appraise the applicability of SP method to the leakage problems of irrigation facilities. The leakage pattern of the dike studied here can be classified into the three categories: leakage through the abutment, leakage by piping through dike, and leakage due to the composite effects of landslide and distortion of the dike structure. for the numerical modeling to interpret quantitatively SP survey results acquired at dike, we have modified the computer code proposed by Sill (1983) to apply to the leakage problems. The numerical studies match the characteristic patterns of SP anomalies according to the leakage types and appear to be very useful to interpret the leakage zone and path. The SP monitoring results were also well coincided with tidal variations observed at every embankment so we found the SP method is quite effective not only to detect the leakage zone but also to determine the leakage trend. The numerical modeling results also reproduced the SP anomalies due to seawater leakage in the embankment.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.19-34
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• 2017

Boron exists in dilute concentrations in sea water, ground water and waste waters. Reactive liquid extraction can be used for removing boron to make the treated water suitable for drinking and irrigation, with its final concentration less than 0.5 ppm. The results of equilibrium experiments are reported on the removal of boron using 2-butyl-2-ethyl-1, 3-propanediol (BEPD as a nonionic carrier) in sunflower oil, a non-traditional solvent. The results of removal of boron from aqueous solutions in the concentration range 0.5-20 ppm are presented. It is shown that this new liquid membrane system, is able to remove boron from ground waters at their natural pH of 6-8 (without any chemical addition for pH adjustments). The removal efficiency is good when the process is upgraded to a hollow-fibre membrane contactor and approximately 45% boron can be removed in a single-stage contact. There are additional advantages of this new approach that includes reduced operational health and safety and environmental issues. The results reported here provide guidelines to the development of boron removal process using renewable, biodegradable, safe and cheap solvent system such as sunflower oil.