An experimental investigation of the behavior of soil water movement under unsaturated transient conditions is reported for the case of vertical infiltration into a sandy loam and silt loam soil material. Water was allowed to enter at a small constant suction into air-dry columns of soil and its subsequent distribution followed with a gamma radiation attenuation device. An analytic expression of water content as a function of depth and time was obtained by multiple regression analysis from which it was possible to determine the instantaneous flux and the water concentration gradient at given water contents. During the early stages of infiltration the relationship between the flux and gradient was linear as prescribed by the Darcy equation. At later times when the gradient became less steep linear proportionality broke down. Non-linearity at low water gradient was evidenced for both soils throughout a wide range of water contents. The magnitude and direction of the departure from linearity was similar for both soils indicating the deviations were possibly not due to specific soil properties, but rather to an inherent characteristic of the flow system itself. An empirical flow equation modeled after the Darcy equation fits the data very well. The behavior of the equation parameters was strongly reminiscent of those of the Darcy equation. Where flux was proportional to the gradient, the equation reduced to the Darcy equation. If flux were not proportional to the water gradient then the term representing the diffusivity of diffusion analysis became a function of both the water gradient and water content.

No description available.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / ABSTRACT This study was an investigation of the impact of recharge water with respect to quality and quantity into the Rehabilitated Block I opencast operation, a former opencast coal mine in Mpumalanga, Witbank Coalfields western complex. The rehabilitated areas consisted of three mined mini-pit areas known as Block I, Block I Extension A and B. The area has been rehabilitated by backfilling and leveling of spoil material, subsoil material, placement of approximately 400-mm topsoil layer and grassing. As part of the vegetation maintenance lime is added per annum, in an effort to neutralize the soil cover and further assist in neutralizing the potential acid mine drainage. Additional monitoring boreholes were drilled to increase the monitoring of the water quantity and qualities. Ground and surface water samples were taken, analysed for pH, conductivity, redox potential, sulphates, carbonates and trace metals. The pH of the ground and surface water ranged from moderately acidic to alkaline. One of the monitoring boreholes located on the lowest elevation of the Block I area was observed to be filled up to the collar level of the borehole with water samples showing elevated Fe and Mn concentrations of 216 and 46.2 mg l-1 respectively. The water classification revealed the following facies: Ca-Mg sulphate type for the borehole water and Ca-Mg sulphate-bicarbonate type for the surface waters. Acid base accounting studies on the soil samples showed a negative net neutralising potential of up to -9.8 kg t-1 CaCO3 which indicated the potential of acid mine drainage in the area. The total metal analyses showed that the area was contaminated with heavy metals such as Fe, Cr, Mn, Ni and Zn and the metalloid As was also detected. The highest recorded concentrations of total metals were 78 252; 2 402; 1 959; 1 360 and 15 109 mg kg-1 respectively. The highest concentration of Arsenic was detected at 824 mg kg-1 respectively. The transmissivity of the boreholes in the spoil material was highly variable and ranges from 100 to 5 000 m2 day-1. Pump testing suggests that borehole yields of between 23 and 4 l s-1 can be expected in the spoil areas. The specific yield or the drainage porosity of the spoil material was in the range of 25 to 30 %.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaf 53). Also available on the World Wide Web.

To improve capabilities for understanding and predicting contaminant migration in fractured rock there is need for better field methods to identify the fractures that have active groundwater flow. Current methods have limitations, for example, borehole geophysical imaging, such as acoustic and optical televiewing, identifies fractures appearing on borehole walls but cannot sense groundwater flow. Borehole hydraulic tests determine the transmissivity of fractured zones under conditions altered by the presence of the borehole and its testing and not under natural flow conditions. The natural flow conditions are important because they govern contaminant transport in the whole flow system. Furthermore, conventional tracer tests are used to identify flow in fractures, but these too are typically done under imposed rather than ambient (natural) hydraulic conditions. High resolution fluid temperature logging in lined boreholes can identify some of the hydraulically active fractures, but this method lacks the sensitivity needed to indicate ambient flow in each individual fracture. This thesis presents a new method aimed at determining whether or not any particular fracture targeted for borehole measurement has substantial ambient flow. This method involves a device lowered into an open hole to a target zone where a packer is inflated. This packer has a water-flow-sensitive dyed cotton fabric wrapped around its exterior so that when the packer is inflated, it not only seals the borehole but presses the cotton fabric against the borehole wall. This set-up causes the exact location of hydraulically active fractures at the borehole wall to show up as imprints marked on the fabric. When viewed under black light, individual fracture markings can be seen, and the distribution of the hydraulically active fractures is identified. For this new method, a prototype system was developed for use in 10cm diameter wells and was tested first in a conventional slotted well screen in the laboratory and then in a simulated fracture (slotted) PVC pipe installed in a sandy aquifer where groundwater flow rates are well understood. From a large number of fabric/dye combinations tested in the laboratory, it was found that cotton dyed with a particular food grade additive provides the best fracture markings by far. The prototype system uses the double-acting packer system originally developed by Solinst Canada, and this novel packer design provides ease of use and flexibility for configuring multiple packers on a single pipe. This prototype system is now ready for the first field trials in a fractured dolostone borehole in Guelph, ON. While the ability of the device to identify active fractures as effectively as it has in the slotted casing trials may be reduced by the interaction of the dye with the porous rock matrix, it is anticipated that this new system for identifying hydraulically active fractures under resealed borehole flow conditions (resealing brings flow back to ambient conditions) will be useful in its own right in fractured rock investigations. This device also represents the first step in the creation of a more elaborate device to measure both the groundwater flux and the contaminant flux within plumes in fractured rock.

To improve capabilities for understanding and predicting contaminant migration in fractured rock there is need for better field methods to identify the fractures that have active groundwater flow. Current methods have limitations, for example, borehole geophysical imaging, such as acoustic and optical televiewing, identifies fractures appearing on borehole walls but cannot sense groundwater flow. Borehole hydraulic tests determine the transmissivity of fractured zones under conditions altered by the presence of the borehole and its testing and not under natural flow conditions. The natural flow conditions are important because they govern contaminant transport in the whole flow system. Furthermore, conventional tracer tests are used to identify flow in fractures, but these too are typically done under imposed rather than ambient (natural) hydraulic conditions. High resolution fluid temperature logging in lined boreholes can identify some of the hydraulically active fractures, but this method lacks the sensitivity needed to indicate ambient flow in each individual fracture. This thesis presents a new method aimed at determining whether or not any particular fracture targeted for borehole measurement has substantial ambient flow. This method involves a device lowered into an open hole to a target zone where a packer is inflated. This packer has a water-flow-sensitive dyed cotton fabric wrapped around its exterior so that when the packer is inflated, it not only seals the borehole but presses the cotton fabric against the borehole wall. This set-up causes the exact location of hydraulically active fractures at the borehole wall to show up as imprints marked on the fabric. When viewed under black light, individual fracture markings can be seen, and the distribution of the hydraulically active fractures is identified. For this new method, a prototype system was developed for use in 10cm diameter wells and was tested first in a conventional slotted well screen in the laboratory and then in a simulated fracture (slotted) PVC pipe installed in a sandy aquifer where groundwater flow rates are well understood. From a large number of fabric/dye combinations tested in the laboratory, it was found that cotton dyed with a particular food grade additive provides the best fracture markings by far. The prototype system uses the double-acting packer system originally developed by Solinst Canada, and this novel packer design provides ease of use and flexibility for configuring multiple packers on a single pipe. This prototype system is now ready for the first field trials in a fractured dolostone borehole in Guelph, ON. While the ability of the device to identify active fractures as effectively as it has in the slotted casing trials may be reduced by the interaction of the dye with the porous rock matrix, it is anticipated that this new system for identifying hydraulically active fractures under resealed borehole flow conditions (resealing brings flow back to ambient conditions) will be useful in its own right in fractured rock investigations. This device also represents the first step in the creation of a more elaborate device to measure both the groundwater flux and the contaminant flux within plumes in fractured rock.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves [135]-139). Also available on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 254-259). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--University of Nevada, Reno, 2008. / "Decmber 2008." Includes bibliographical references (leaves 60-62). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1958. / Includes bibliographical references (p. 189-192).