• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.51-56
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• 2019

Biofilms facilitate communication among microorganisms for nutrients and protect them from predators and harmful chemicals such as antibiotics and detergents. Biofilms can also act as cores for the development of clogs in many agricultural irrigation systems and in porous media. In this study, we deployed glass units at a depth of 20 m below the ground surface in the groundwater-surface water mixing zone, and retrieved them after 4 months to investigate the potential colonization of indigenous microbial community and possible mineral-microbe assemblages. We observed the periodic formation of microbial colonies by fluorescence dye staining and microscopy, and analyzed the composition of the microbial community in both the mineral-microbe aggregates and groundwater, by next generation sequencing of the 16S rRNA gene amplicons using MiSeq platform. During the course of incubation, we observed an increase in both the mineral-microbe aggregates and content of extracellular polymeric substances. Interestingly, the microbial community from the aggregates featured a high abundance of iron redox-related microorganisms such as Geobacter sp., Comamonadaceae sp., and Burkholderiales incertae sedis. Therefore, these microorganisms can potentially produce iron-minerals within the sediment-microbe-associated aggregates, and induce biofilm formation within the groundwater borehole and porous media.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.468-471
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• 2004

Groundwater development as a means of acquiring subsidiary water resource is very important for the persistent security of water resource. Nowadays, pneumatic fracturing technology which was developed in the advanced countries is applied for increasing pumping rate and eliminating contaminants. From the results of this study, hydraulic aperture and permeability are presented.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.235-237
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• 2005

• Tunnel and Underground Space
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• v.19 no.3
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• pp.248-260
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• 2009

With regard to oversea mineral resources development, recent trend has been changed from a simple capital investment to a direct development of the resources. In relation to the stability of a slope in large open-pit coal mine, groundwater system was investigated and the validity of horizontal drainage hole was evaluated in Pasir coal mine, Indonesia. In this work, various field tests were carried out for a characterization of groundwater system, which included in-situ permeability measurement, tracer test and monitoring of groundwater levels. Especially, the influence of SM river on the characteristics of the groundwater flow system was mainly inspected. For the permeability measurement, Guelph permeameter was employed, and was found that sandstone was more permeable than mudstone and coal seam. From a comparison of lithological structure and the results of groundwater level monitoring, sandstone and thin coal seam with fractures were found to be a main channel for groundwater flow. In the results of tracer tests, the effect of SM river on the groundwater system depends on the geological structure of its base. To identify the effect of horizontal drainage holes, 2-D groundwater modeling was performed. Four different cases were tested, which are different from the length of drainage hole and the existence of pond on top of the slope. To enhance the drainage effect and slope stability, the drainage hole should be drilled to the depth of coal seam layer, which provides a main pathway of groundwater flow and embedded by sandstone. For this purpose, correct identification of surrounding geology should be preceded.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.218-226
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• 2016

Field observations were used to study the characteristics and influence of groundwater level fluctuations on vegetation development on the natural beach of a sandy barrier island, in the Nakdong River estuary. The spatial/temporal fluctuations of the groundwater level and the interactions with the external forces (weather, ocean wave and tide) were analyzed. The results indicated that when it rains the groundwater level rises. During summer, when precipitation intensity is greater than 20 mm/hour, it rose rapidly over 20 cm. Subsequently, it fell gradually during periods of no precipitation. Seasonal characteristics indicated that the groundwater level was high during the summer rainy season and tended to fall in the winter dry season. The time-averaged groundwater level, observed from the four observations over 3 years (2012-2014), was about 1.47 m, higher than mean sea level (M.S.L.). It was shown that the average annual groundwater level rises toward the land rather than showing intertidal patterns observation. Differences in the presence or absence of a coastal sand dunes affected the progress of vegetation. In other words, in environments of saltwater intrusion where the groundwater level varies, dependent on the distance from the shoreline and bottom slope, sand dunes can be provided to affect soil conditions and groundwater, so that vegetation can be grown reliably.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.6
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• pp.1259-1267
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• 2015

In Korea, rural groundwater development faces new challenge, which have not been experienced so far. The problem is a groundwater depletion by the water curtain cultivation (WCC) during winter season. This study investigates the groundwater depletion using three-dimensional finite difference groundwater flow program, MODFLOW to verify the water budget of the shallow aquifer of Cheongweon area. Interdisciplinary research, which has become a worldwide trend, has been adopted in studying groundwater modeling in field scale. In particular, the method of groundwater recharge estimation adopted precise modeling techniques, SWAT to groundwater flow modeling. Based on qualified field data, the model calibrated and validated its reliability. The objective of this study is to simulate various stream-aquifer interactions according to groundwater pumping with artificial boundaries, such as weirs and drainage system. We also analyzed a seasonal variation of cumulative water budget of the site to quantify the groundwater depletion and recovery in the pumping field.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.8-14
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• 2007

Water quality in Lake Rotorua, New Zealand, deteriorated since the 1960s because of excessive phytoplankton growths due principally to increasing nitrogen and phosphorus in the lake waters. Nutrient concentrations in eight of the nine major streams feeding Lake Rotorua have increased since 1965. The groundwater system has a key role in the hydrology of the Lake Rotorua catchment and the groundwater system is probably the control on the time delay between intensification of agricultural land use and response of surface water quality. All major, and many minor streams, in the catchment are fed by springs. Two lithological units are most important to groundwater flow in the Lake Rotorua catchment: Mamaku Ignimbrite, erupted in about 200,000 years ago and Huka Formation sediments which filled the caldera left by the Mamaku Ignimbrite eruption. Rainfall recharge to groundwater in the groundwater catchment of Lake Rotorua is estimated as approximately 17300 L/s. A calibrated steady-state groundwater flow model estimates that approximately 11100 L/s of this flow discharges into streams and then into the lake and the balance travels directly to Lake Rotorua as groundwater discharge through the lake bed. Land use has impacted on groundwater quality. Median Total Nitrogen (TN) values for shallow groundwater sites are highest for the dairy land use (5.965 mg/L). Median TN values are also relatively high for shallow sites with urban-road and cropping land uses (4.710 and 3.620 mg/L, respectively). Median TN values for all other uses are in the 1.4 to 1.5 mg/L range. Policy development for Lake Rotorua includes defining regional policies on water and land management and setting an action plan for Lake Rotorua restoration. Aims in the action plan include: definition of the current nutrient budget for Lake Rotorua, identification of nutrient reduction targets and identification of actions to achieve targets. Current actions to restore Lake Rotorua water quality include: treatment of Tikitere geothermal nitrogen inputs to Lake Rotorua, upgrade of Rotorua City sewage plant, new sewage reticulation and alum dosing in selected streams to remove phosphorus.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.323-329
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• 2009

This study was conducted to analyze growth responses of fast growing tree species(8 clones of hybrid poplars, Salix alba, Metasequoia glyptostroboides, Liriodendron tulipifera, Acer okamotoanum, and Quercus palustris), the chemical characteristics of soil and $NO_3-N$ concentration of groundwater in a plantation applied with liquid pig manure. Concentrations of nitrogen and phosphorous in the soil treated with liquid pig manure were higher than that of the soil treated without liquid pig manure. With the exception of S. alba, DBH(Diameter at Breast Height) growth of all the fast growing tree species treated with liquid pig manure was higher than that of the species treated without liquid pig manure. In liquid pig manure treatment group, P. euramericana 'Eco28' clone showed the best performance in height and DBH growth. Concentration of nitrogen in the leaf with liquid pig manure was higher than that of the leaf treated without liquid pig manure. Based on the $NO_3-N$ concentration of groundwater analyzed during the experimental period, there was no evidence that groundwater was polluted by the liquid pig manure applied at the plantation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.62-63
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• 2005

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.148-149
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• 2005