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  • Language: English
  • Publication Year: From Year 1900 To Year 2020
  • Title: Journal of Groundwater Hydrology OR

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Spring waters were sampled at the discharging points and analyzed for EC and major anions in three small spring complexes located near Madison, Wisconsin. The purpose of this study was to elucidate a meter-scale spring water chemistry variation at the time of discharge, which may shed light on underground flow paths of the spring water.
The major anion concentrations (Cl and NO3) showed strong effect of land use such as road salts in the urban watershed and N-fertilizer applications in agricultural fields. The STDs of Cl in an urban watershed and NO3 in an agricultural watershed were 27.4% and 39.9% of their average concentrations, respectively. It was found that the major anion concentration in each spring complex has large spatial variations even within a meter-scale separation.
Based on the hydrogeology and land use of the watersheds, the large chemistry variation observed could be caused by the solutes from different source areas, that converge towards a small discharge zone with little mixing and discharge into close but different points in the same spring complex.
Acquisition of more detailed information on hydrogeology and water quality is required to better understand the causes of the observed large variation of chemistry within a single spring complex.
Characteristics of the chemical composition of groundwater on Tanegashima, Yakushima, and Nakanoshima islands, Kagoshima Prefecture, Japan
  • Seizen AGATA, Maki ISHIKI, Hideaki SAKIHAMA, Akira TOKUYAMA, Hiroshi SATAKE, Jing ZHANG
  • Journal of Groundwater Hydrology
  • Vol. 54 (2012) No. 4
  • Released: December 14, 2012
Twenty-six groundwater samples were collected From Tanegashima, Yakushima, and Nakanoshima islands between July 27 and August 2, 2003. The interpretation of chemical analyses suggested that the groundwater on the islands have been affected by sea salt (ss). Chlorine (Cl-) concentrations on Yakushima, which were inversely related to elevation, were considerably lower than those on Nakanoshima and Tanegashima, reflecting higher annual rainfall on Yakushima. However, groundwater samples from Yakushima had a higher ratio of ss components—more than 50% (except one sample). Non-sea salt (nss) components of the groundwater on Tanegashima, Yakushima, and Nakanoshima were found to be affected mostly by the chemical weathering of plagioclase feldspars. The groundwater on Tanegashima was also thought to be affected by ion exchange between clay minerals and Ca2+. The effects of sulfuric acid and carbonic acid on chemical weathering were nearly equivalent on Nakanoshima. Therefore, the average concentrations of nssSO42- and dissolved SiO2 were remarkably higher than those for Yakushima and Tanegashima. The arithmetic mean concentration of nssK+ on Yakushima was high even though the total concentration of all nss components was low. The nssK+ probably originates from chemical weathering of K-feldspar in granite. The total concentration of nss components on Yakushima was remarkably lower than that on Tanegashima or Nakanoshima. Low NO3--N concentrations in these mountainous and forested islands reflect a low load from anthropogenic activities.
No suitable method has yet been found for the study on the texture, the structure and the mineral composition of the deep weathered granites, which has been called the Masa. In this paper, it is reported that the writer has made the systematic study of the disintegrated and the weathered granites. Its method is the analysis of the relationship between the distance from the fault and the diameter of the particles, and also the analysis of the cumulative curve for the size distribution, the apparent specific gravity, the seismic sounding, the electric prospecting, the relief quantity. The area reseached by the writer covered nearly over the whole area of Rokko mountains, Hyogo Pref., Dogo Dist., Ehime Pref., Yashima, Kagawa Pref., Sanage Dist., Aichi Pref. and the other regions.
[title in Japanese]
The present study investigates how the sawdust material affects the biological treatment and biological clogging in porous media.
Serial data from soil-sawd u st column experiments were used to develop a model to describe the biological treatment and biological clogging processes in porous media. A model was developed simulating solute transport with biological treatment in soil-sawdust experimental columns including biological clogging processes. The transport part of the model solves the advection dispersion differential equations and the reaction part describes the heterotrophic metabolisms of several groups of bacteria. To simulate the biological clogging effects, the changes in porosity are calculated by converting biomass into volume, which directly reduces the porosity.
Developed model could be evaluated experiment results. And it is confirmed that sawdust materials could be expected as the materials which could be encouraged biological treatment and improved the hydraulic conductivity.
Runoff analyses are important to efficient l y manage the watersheds such as precise prediction of discharge. Runoff is mainly composed of surface and groundwater flow components, therefore hydrological conditions should be well described before any runoff analysis. In this study, runoff analyses were performed for two small sub-basins of a mountainous catchment of Tono area Japan with the aim to forecast runoff after 1 and 1/2 hours by using 3 different numerical models and performances of these models were compared to each other. The runoff and other meteorological data have been collected in these sub-basins over the last 14 years. The effect of the basin area on the prediction time of runoff and the seasonal data impacts were also investigated. For the analyses, a new approach of training artificial neural network model (ANN) with real coded genetic algorithm (GA) named as GAANN model is proposed. The results of this model were compared with famous back propagation artificial neural network (BPANN) model and with multivariate autoregressive moving average model (MARMA). It was found that for very small catchments seasonal effect on the runoff is dominant and this effect should be considered for obtaining better forecasting estimates. It was also found that estimation by ANN models was better than MARMA model for analyzing the responses to intense rainfalls in summer, whereas the results were almost similar for the light rains of winter season. The accuracy of the forecasts after several time periods in future was also investigated and found to decrease as the time period is increased. The results showed that GAANN and BPANN models almost provided similar prediction estimates in a very small mountainous watershed when precisely measured dataset was used. Modelling advantages of using genetic algorithm instead of back propagation for the training of ANN models are also highlighted.
Effects of polylactate ester-type time-release electron donor on generation and maintenance of reductive condition in river sand microcosms
  • Journal of Groundwater Hydrology
  • Vol. 47 (2005) No. 3
  • Released: December 11, 2012
Hydrogen Release Compound (HRC) is an important electron donor that is now becoming widely used in accelerating the biological reductive dechlorination of chlorinated aliphatic hydrocarbons (CAHs). HRC is a polylactate ester specially formulated for the slow time-release of lactic acid. Lactic acid is then metabolized while producing hydrogen, which can be used in the reductive dechlorination of CAHs. We investigated the effect of HRC on the generation and maintenance of reductive condition in river sand microcosms with the nonaddition or addition of the HRC-degrading bacteria. Oxidation-reduction potential (ORP) was used as an evaluation parameter for detecting the development of reductive condition following HRC addition to such microcosms. The results revealed that HRC, particularly purified HRC (polymer components of commercial HRC), excels in producing and maintaining a low ORP in the long term, which is the most desirable condition for the reductive dechlorination of CAHs.
Analysis of groundwater flow in a fractured rock mass in Pahala Mattala area, Sri Lanka using Don-Chan, a three-dimensional channel network model
The behavior of groundwater flow in a fra ctured rock mass in Pahala Mattala area, southern Sri Lanka was studied. Hydrogeological data obtained by Water Resources Board in Sri Lanka (WRB)and Japan International Cooperation Agency (JICA) was used in this study. Idealized models of fractured rock mass were constructed on the basis of the fracture data. Don-Chan (Donen-Saitama Channeling Flow Model), channel network model, was adopted for the analysis of groundwater flow and it was assumed that the fractures are divided into three types: major fractures, minor fractures and fault zones. Pumping test results obtained by two wells were analyzed with the' aim to calibrate channel transmissivity values of different fracture types. Model verification was done using pumping test results obtained by another combination of wells. It was found that, the channel network model in the Pahala Mattala area had the capability to predict accurately the groundwater flow for new pumping operations that will be planned in future to develop groundwater resources in deep underground.
The significant decline of groundwater lev e l every year causes a repeated groundwater crisis in Bandung area, west Java, Indonesia. Information about ground water recharge becomes important in order to be able to identify the relationship between input and output water in this region. Although, various techniques are available to approach the estimation of recharge, the lack of artificial wells and records of the groundwater fluctuation in the recharge area obstructs the recharge estimation. In the present study, we used the available data of streamflow hydrograph to assess the potential amount of a groundwater recharge based on base-flow recession. The results indicated that the recharge was approximately 566.36 mm/year and 292.39 mm/year or 20.97 and 14.59 percent of the rainfall nets in 1992 and 1993, respectively. The estimated groundwat er storage was approximately 16.15 % in 1992 and 4.15 % in 1993 of rainfalls.
Underground dam technology in some parts of the world
Increased human population, changing l ifestyles and land use have resulted in intensive exploitation of groundwater resources worldwide. To improve on the availability of groundwater, numerous techniques have been developed in many parts of the world. One of such techniques is the construction of underground dams. The widespread application of this technology, however, has been limited by lack of information on the design, construction and utilization of the dam. This paper therefore reviews underground dam technology in some parts of the world to meet this challenge. The investigations required for selecting suitable sites, the materials and construction methods used and the results of some research works are presented.
Options for Skimming Fresh Groundwater in the Indus Basin of Pakistan: A Review
The aquifer under the Indus basin of Pakistan is of marine origin and the native groundwater is saline which is overlain by a freshwater layer. The upper freshwater layer is formed as a result of seepage from rivers, canals, field irrigation losses and precipitation. About 6.42 million ha area has freshwater layer of variable thickness. The exploitation of upper freshwater layer is hindered by saline water intrusion and saline upconing under pumping wells. To extract this freshwater for agricultural, domestic and industrial purposes, different techniques are being practiced in the Indus basin to minimize the saline water intrusion. These include; shallow tubewells, skimming tubewells, scavenger wells, dug wells, and radial collector wells. The adoptability of these techniques depends upon the thickness of the freshwater layer, availability of local material, availability of technical personnel for installation and maintenance, local customs and traditions, and the affordability. The present paper reviews the skimming well technologies used for extracting freshwater in various parts of the Indus basin of Pakistan, their feasibility in different part of the basin, the present status of these techniques and associated constraints.
6. Effects of groundwater exchange on the hydrology and ecology of surface waters
Groundwater exchange affects the ecology of surface waters by sustaining stream baseflow and stabilizing the water level of groundwater-fed lakes. It also provides stabletemperature habitats, and supplies nutrients and inorganic ions. Groundwater input of nutrients can even determine the trophic status of lakes and the distribution of macrophytes. In streams the mixing of groundwater and surface water in shallow channel and bankside sediments creates a unique environment called the hyporheic zone, an important component of the lotic ecosystem. Localized areas of high groundwater discharge in streams provide thermal refugia for fish. Groundwater also provides moisture to riparian vegetation, which in turn supplies organic matter to streams and enhances bank resistance to erosion. As hydrologists and ecologists interact to understand groundwater' s impact on aquatic ecology, a new research field called“ecohydrology”is emerging.
In order to evaluate submarine groundwater discharge (SGD) rates continuously and automatically, a“continuous heat-type”automated seepage meter was newly developed, and it was applied to Tannowa, Osaka Bay, Japan. The meter is based on the measurements of the temperature gradient of the water between the downstream and upstream positions in a pipe. According to two months continuous measurements of SGD every 10 minutes, semi-diurnal periodical changes in SGD were found in Tannowa. This is attributed to the tidal effects on SGD. The time delay of the SGD from tidal records was also found to be about 5 hours. The newly developed automated seepage meter can provide longer-term and higher-resolution measurements of SGD, which helps us to understand temporal scale issues on SGD and the relevant hydrological and coastal oceanographic processes.
To elucidate the two-dimensional migration and distribution of non-aqueous phase liquids (NAPLs) in soils, downward migration and lateral spreading of pure 1,1,1- trichloroethane (TCA) and toluene through a layer of glass beads was observed. In particular, the behavior of both fluids in the unsaturated zone and in the vicinity of a water table was investigated, by considering mass balances (residual NAPL distributions, dissolution and volatilization). In a 24-hour experiment, about 21 % to 24 % of TCA (50 mL) volatilized,0.4 to 2 % dissolved, and about 75 % remained as pure liquid in the layer of glass beads. In a 24-hour experiment, about 5 % of toluene (50 mL) volatilized,0.02 to 0.2 % dissolved, and about 95 % remained as pure liquid. The amount of pure TCA remaining above a water table (in the unsaturated zone and saturated capillary zone), which apparently acts as a barrier for NAPL infiltration, reached 30 to 48 %. Lateral spreading of pure TCA above the water table was found to be very small and negligible. A further experiment simulating groundwater fluctuations suggested that pure toluene, even if its migration has stopped, would be transported downgradient again when a water table falls.
Two-Dimensional Random Walk Program for the Calculation of the Tortuosity of Porous Media
A program‘RW2D.m’for Mathematica vet 4 was made to calculate the tortuosity of the porous media. It is a lattice walk program on the two-dimensional space. The program reads a two-dimensional digital image of porous media and random walkers migrate in the pore space by avoiding the obstacles. The output of the program is the mean-square displacement of the walkers and a graphic trajectory of a walker. The tortuosity is calculated using the mean-square displacement of the lattice walk in the porous media and that in free (i. e., porosity=100%) space. The program requires that (1) the structure of the porous media is isotropic, (2) effects of the chemical interaction of the diffusants and the solid surface (e. g., adsorption) are negligible, and (3) the digital image contains backbone clusters of pores. When the requirements are satisfied, the program‘RW2D.m’enables us to calculate the tortuosity using the two-dimensional image of the porous media without time-consuming laboratory diffusion experiments. We open this free program to the public to facilitate the diffusion study on porous media.
Volatilization of Non-Aqueous Phase Liquid in Porous Media: Vapor Phase Mass Transfer Characteristics
Interphase mass transfer is an important process that dominates overall transport processes in multi-fluid system in porous media. This process plays a key role during the volatilization of non-aqueous phase liquids (NAPLs) in porous media that usually takes place during the remediation process of volatile organic compounds (VOCs) using soil vapor extraction (SVE) technique. Previously, interphase mass transfer coefficient was usually lumped together with interfacial area between air and liquid because of inaccessibility to quantify the interfacial area due to the heterogeneous nature of the pore structure of the media and the morphology of the fluid distribution. An effort was made to estimate the air-liquid interfacial area in three glass beads media using surfactant adsorption concept and was found decreasing with increasing liquid saturation. A series of one-dimensional NAPL volatilization experiments were carried out in a horizontal column for the same three-glass beads media using Toluene as the contaminant. Experiments were conducted for NAPL saturation range of 13.8∼71% and a pore gas velocity of 0.1∼2 cm/s and lumped mass transfer coefficients were evaluated. Actual vapor phase mass transfer coefficients were calculated using corresponding air-liquid interfacial area for a specific NAPL saturation and was characterized in dimensionless form for all the porous media used in the study. Results showed that the vapor phase mass transfer coefficient increases with increasing pore gas velocity and grain size but decreases with increasing NAPL saturation.
Estimation of Actual Evaporation and Soil Moisture Conditions
In planning the management of groundwater resources in desert areas, the temporal variation and spatial distribution of actual evaporation must be evaluated accurately because evaporation is important as not only a main component of the loss of water resources but also as a factor affecting rainfall amount. In this study, an energy balance model for the estimation of actual evaporation from bare soil surfaces is developed. The model does not require observations of soil moisture and can estimate simultaneously an index of soil moisture conditions using several meteorological elements and soil characteristics as inputs. The model was applied to field observation data from three different bare land sites. In all cases, the estimated evaporation rate was found to agree very well with the observed result. The behavior of the estimated effective-evaporation zone was compatible with the soil moisture conditions of the surface soil layer for each site.
The subsurface was contaminated by about 3,000l, of kerosine that percolated into the ground from a corroded subsurface pipeline in M City. Along with remediation of the contaminated groundwater mainly by pump-and-treat, investigations of lithology, groundwater flow systems, and groundwater chemistry were performed. A series of pumping tests was conducted throughout a two-year remediation period and the drawdown data were analyzed using a graphical method based on Neuman's analytical solution for pumping tests in unconfined aquifers. The analysis revealed that hydraulic conductivities and storage-related parameters were highly affected by the leakage of the kerosine, in particular during the first year after the leakage occurred. The objective of this paper is to show temporal changes in these hydrogeologic properties due to clogging of aquifer pores, which are deduced to be caused by the entrapment of liquid kerosine in pore spaces, the growth of bacterial cells, and the precipitation of inorganic solids.
Method of Estimating Air-Liquid Interfacial Area Using Soil Characteristics Curve
Air-liquid interfacial area (αi) is an important parameter in the subsurface hydrology that describes the pore scale distribution of air and liquid inside the porous media. In order to quantify this parameter, a theoretical model using soil characteristics (ψ-θ) curve was developed by introducing a term“hydraulic radius”for the pores inside the medium. This term diminishes the effect of any shape of the pore. The derivation becomes a simple expression which needs only drainage soil characteristics curve. In this study,ψ-θ curves were developed experimentally for three glass beads media (0.25mm,0.50 mm and 0.75mm) and the theoretical method was applied successfully to estimate the parameter, αi in these different porous media. Results obtained by this method follow the general concept of decreasing αi with increasing liquid saturation. They also show that the αi is increasing with decreasing grain size, which supports the frequency distribution of the pore sizes inside the porous media. Estimated air-liquid interfacial area was also compared with the results obtained by an experimental technique using surfactant mass extraction. Comparison of the results shows that the interfacial area determined by this theoretical method provides reasonable estimation. Finally, the method was applied to a sand mixture (d50=0.25mm) to estimate the air-liquid interfacial area and was compared with the experimental results of interfacial tracer technique as described by Kim et al., (1997). Results found by comparing αi of solid surface area at zero saturation revealed that the theoretical method provides reasonable estimation of αi than the interfacial tracer technique.