• Journal of Korean Society on Water Environment
• /
• v.27 no.1
• /
• pp.115-119
• /
• 2011

The mobility of groundwater in the soil environment has an important role in the soil environment and absorption of plant. Therefore, studies on the mobility of groundwater considering the physical and chemical properties of soil is very important. In this study, movement of water due to change in soil particle size were observed by capillary rise. The height of the capillaries was measured according to capillary diameter, temperature and solution concentration. The inner diameter of each capillary itself is 0.012, 0.016, 0.024, 0.027 cm, and experiments were performed at $22^{\circ}C$. As a result, the height of the capillaries decreased with increasing capillary diameter, and the solution temperature but increased with increasing concentration. Changes in the height of the capillaries are interpreted to related with surface tension by the Young-Laplace equation. Also on the mobility of groundwater, the increase of water and soil temperatures can be significant factors caused by ion strength and global warming as well as pores in the soil particles. The results of this study is considered to provide the basic data on the behavior of groundwater in the soil environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.87-90
• /
• 2000

The hydrogeochemical and isotopic studies on deep groundwater in the Munkyeong area, Kyeongbuk province were carried out. $CO_2$-rich groundwater (Ca-HC $O_3$ type) is characterized by low pH (5.8~6.5) and high TDS (up to 2,682 mg/L), while alkali groundwater (Na-HC $O_3$ type) shows a high pH (9.I~10.4) and relatively low TBS (72~116 mg/L). $CO_2$-rich water may have evolved by $CO_2$ added at depth during groundwater circulation. This process leads to the dissolution of surrounding rocks and Ca, Na, Mg, K and HC $O_3$ concentrations are enriched. The low Pc $o_2$ (10$^{-6.4}$atm) of alkali groundwaters seems to result from the dissolution of silicate minerals without a supply of $CO_2$. The $\delta$$^{18}$ O and $\delta$D values and tritium data indicate that two types of deep groundwater were both derived from pre-thermonuclear meteoric water. The carbon Isotope data show that dissolved carbon in the $CO_2$-rich water was possibly derived from deep-seated $CO_2$ gas. The $\delta$$^{18}$ S values of dissolved sulfate show that sulfate reduction occurred at great depths. The application of various chemical geothermometers on $CO_2$-rich groundwater shows that the calculated deep reservoir temperature is about 130~175$^{\circ}C$. Based on the geological setting, water chemistry and environmental isotope data, each of the two types of deep groundwater represent distinct hydrologic and hydrogeochemical evolution at depth and their movement is controlled by the local fracture system.m.

• Economic and Environmental Geology
• /
• v.27 no.1
• /
• pp.93-100
• /
• 1994

This study examined the mechanisms of lead transport in the groundwater system and those of irregular detections in groundwater in Door County, Wisconsin. During the spring recharge period in 1991, water-level movement and water-quality change were monitored from two monitoring wells equipped with three piezometers each and from five house wells, respectively. Water-level responses to recharge events were fast with a relatively short lag time ranging from 3 to 10 days, indicating that recharge of groundwater occurs through the high hydraulic conductivity (K) zones in the Silurian dolomite aquifer system. Lead was detected only on particles filtered from groundwater, but not in dissolved state. Concentrations ranged from 0.2 to $7.1{\mu}g/mg$, converted into the total lead concentration in groundwater ranging from $0.3{\mu}g/l$ to $4.7{\mu}g/l$. A lag time between recharge events and peak particle movement at the sampled wells was estimated to range from 19 to 22 days. Due to the particulate nature of lead in groundwater, only the wells connected with the high K zones detect lead, causing the spatial variation. In a given well, lead concentration varies at different sampling times due to the variation in the initial amounts of lead-carrying particles introduced into the groundwater system during recharge events, the lag in particle transport and the dispersion of lead-carrying particles along the advective flowpaths.

• Journal of Korean Society of Rural Planning
• /
• v.24 no.2
• /
• pp.47-58
• /
• 2018

Protected horticultural complexes would increase crop productivity but would adversely affect the groundwater recharge function in the area because the impervious area would increase. Further, they would limit the movement of living beings, affecting biodiversity. Therefore, this study evaluated the groundwater ecosystem services provided by protected horticultural complexes in terms of consistent utilization of water. The estimated amounts of groundwater loss obtained through quantitative assessment of groundwater infiltration showed that a higher impervious area results in higher losses. We, therefore, predict a much higher loss if similar changes in land use are realized on a nationwide scale. A plan to promote groundwater recharge in impervious areas is actively being discussed for urban areas; however, this plan is not yet applicable to farming areas. We consider it is essential to develop groundwater infiltration facilities for horticultural complexes, infiltration trenches, permeable pavements, surface water storage facilities, water purification facilities, etc. Further research and development of groundwater infiltration facilities is important for consistent utilization of water and the improvement of ecosystem services.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.5
• /
• pp.699-715
• /
• 2019

Recently, in urban areas, cavities and ground collapse adjacent to underground structures are frequently reported. Several studies on the cavity generation by structure cracks have been made, however they are focused on the cause of cracks and settlement of the ground. In this paper, soil particle and groundwater discharge through pipe cracks and cavity generation mechanism are investigated. The theoretical analysis of the groundwater, which is the main factor of the drainage of the soil particles, and the particle transport mechanism and flow characteristics were investigated. An experimental model test was carried out to identify the mechanism of cavity generation by underground buried pipe cracks. The soil particle weight of discharge through the cracks, and the movement characteristics of the particles were analyzed using PIV. In this study, it is clearly identified that soil particle movements, cavity generation and ground collapse that occur in the ground are basically caused by the movement of groundwater.

• Korean Journal of Agricultural Science
• /
• v.45 no.3
• /
• pp.521-532
• /
• 2018

In recent decades, the dry stream phenomena of small and medium sized rivers have been attracting much attention as an important social problem. To prevent dry stream phenomena, it is necessary to build an infrastructure that manages rivers. To accurately determine the progress of dry stream phenomena, it is necessary to continuously measure the discharge and other hydrological factors for small and medium sized rivers. However, until now, the flow data for small and medium rivers in Korea has been insufficient. To overcome the lack of supporting data for supporting rational decision-making in policy and project implementation, a short- and long-term hydrological model was developed that takes into consideration hydrological changes such as the increase of the impervious area due to urban development and groundwater pumping, the construction of a large-scale sewage treatment plant, the maintenance of stream-oriented rivers, etc. In the developed model, the distributed grid is represented by three layers: Surface flow, interflow, and groundwater flow. The surface flow and intermediate flow flowed along the flow direction, and the groundwater flow was calculated by a two-dimensional groundwater analysis model such that the outflow occurred in all directions without a specific flow direction. The effects of land use and cover on evapotranspiration and infiltration and the effects of multiple landscapes can be simulated in the developed model.

• The Journal of Engineering Geology
• /
• v.3 no.3
• /
• pp.241-252
• /
• 1993

Lead bas been found in the groundwater in Door County, Wiscorsin, with temporally and spatially irregular distribution in concentration. Correlation coeffidents were calculated among lead indicators in groundwater(frequency of lead detections, mean and maximum concentration of lead detections) and seven independent variables(stucture and geographic factors of wells, hydrogeological factors at lead-arsenate mixing sites and the level of soil contamination) which are possibly related to the lead level in groundwater. The significance of relationships was determined statistically by a t-test at the 90% confidence level, and indicated that the spatially located lead-arsenate mixing sites provided the lead in groundwater in the study area. A total of 112 groundwater samples were collected from 5 house wells with previous lead detects. Lead was detected in partides on ifiter papers with $0.45{\;}\mu\textrm{m}$ pore size, but not in filtrates. The result of chemical analysis for lead indicates that lead is associated with partides in groundwater in Door County. Subsequently, the irregular distribution of lead in the county results from the transport of particulate lead along the advective groundwater movement through the preferential pathways sucn as vertical and bedding-plane joints.

• Geomechanics and Engineering
• /
• v.15 no.3
• /
• pp.851-859
• /
• 2018

There are two primary causes of the ground movement due to tunnelling in urban areas; firstly the lost ground and secondly the groundwater depression during construction. The groundwater depression was usually not considered as a cause of settlement in previous research works. The main purpose of this study is to analyze the combined effect of these two phenomena on the transverse settlement trough. Centrifuge model tests and numerical analysis were primarily selected as the methodology. The characteristics of settlement trough were analyzed by performing centrifuge model tests where acceleration reached up to 80g condition. Two different types of tunnel models of 180 mm diameter were prepared in order to match the prototype of a large tunnel of 14.4 m diameter. A volume loss model was made to simulate the excavation procedure at different volume loss and a drainage tunnel model was made to simulate the reduction in pore pressure distribution. Numerical analysis was performed using FLAC 2D program in order to analyze the effects of various groundwater depression values on the settlement trough. Unconfined fluid flow condition was selected to develop the phreatic surface and groundwater level on the surface. The settlement troughs obtained in the results were investigated according to the combined effect of excavation and groundwater depression. Subsequently, a new curve is suggested to consider elastic settlement in the modified Gaussian curve. The results show that the effects of groundwater depression are considerable as the settlement trough gets deeper and wider compared to the trough obtained only due to excavation. The relationships of maximum settlement and infection point with the reduced pore pressure at tunnel centerline are also suggested.

• Tunnel and Underground Space
• /
• v.3 no.1
• /
• pp.24-32
• /
• 1993

Groundwater movement is one of the most important elements in the construction and management of underground oil storage cavern. To control the groundwater flow, grouting is run in parallel with water curtains. But as traditional grouting is conducted within cavern before and after excavation, the effect of grouting is delayed and the injection sphere is limited in the rock mass. Therefore, it is desirable to introduce a more extensive and effective grouting. This article is to present the caly grouting, which was the first to be carried out in the construction of underground caverns for oil storage in Japan. After conducting the clay grouting, the effect was confirmed by ground water level and infiltration quantity to the caverns.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.511-514
• /
• 2003

Nowadays, wells tapping the deep aquifers become general because water quality of the shallow groundwater has been gradually degraded over the last 30 years as a result of rapid industrialization and intensive agricultural activities. However, many of the deep wells also suffer problems of water-quality degradation in several years after the well installation, nevertheless those were properly completed and managed. It is believed that the heavy pumping from deep wells causes the doward movement of the contaminated, shallow groundwaters and introduces them into the deep aquifers. In this study, we introduces a shallow capture well system, which could effectively prevent the shallow groundwaters of poor water duality from moving into the deep aquifers by pumping of deep production wells. Even though additional costs are required to apply this system, we believe that this method could be appropriate for the deep wells that are important for the public health.