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Contaminant transport mechanisms in karst terrains and implications on remediation
HYDROGEOLOGY:FLUID FLOW understanding of the physics and chemistry involved during electrokinetic treatment of contaminated soils. (from Authors)
962097 Approximate mix'ted-integer nonlinear programming methods for optimal aquifer remedintion design D. C. McKinncy & Min-Der Lin, Water Resources Research, 31(3), 1995, pp 731-740. An optimal aquifer remediation design model employing a nonlinear programming algorithm was developed to find the minimum cost design of a pump-and-treat aquifer remcdiation system. The mixed-integer nonlinear programming model includes the discontinuous fixed costs of system construction and installation as well as operation and maintenance. The polynomial penalty coefficient method results were compared to two alternatives. The polynomial penality coefficient method obtains the same solutions and performs as well as or better than the exponential penality coefficient method. It also almost always results in better, less expensive designs and requires significantly less computer time than the pseudo-integer method. (from Authors)
962098 Groundwater remediation design using a three-dimensional simulation model and mixed-integer programming C. S. Sawyer, D. P. Ahlfeld & A. J. King, Water Resources Research, 31(5), 1995, pp 1373-1385. A three-dimensional groundwater flow management model for making decisions on the design of hydrodynamic control of a groundwater fl0w system using a combination of extraction and/or injectionwells is developed. The mathematicalformulation of the groundwater remediation problem as a mixed-integer model and the strategy for solving the model arc presented. Numerical resultsare presented for the Toms River Plant site, which is modeled as a five-layer aquifer system with interconnecting aquitards. (Authors)
962099 Contaminant transport mechanisms in karst terrains and implications on remediation W. Barncr & K. Uhlman, in: Karst geohazards: engineering and environmental problems in karst terrane. Proc. 5th conference, Gatlinburg 1995, ed B.F. Beck, (Balkema), 1995, pp 207-212. Because successful implcmeptation of ground water remediation cannot be achieved without a full understanding of dissolved and non-aqueous phase transport mechanisms, the hydrogcologist must rely on developing a site conceptual model based on interpretation of field data. Investigative techniques for predicting the probable location of both lightand dense-non-aqueous phase liquid (LNAPL and DNAPL) in the flow continuum of karst aquifers are presented in this paper within the framework of ground water remcdiation options. (from Authors)
962100 Modified soil water retention functions for all matric suctions M. J. Fayer & C. S. Simmons, Water Resources Research, 31(5), 1995, pp 1233-1238. The Brooks-Corey and van Genuchten functions were modified to adequately represent retention at all matric suctions. The modification consisted of replacing the residual water content with an adsorption equation (Campbell and Shiozawa, 1992). The modified functions retain the form of the original functions in the wet range and the form of an adsorption equation in the dry range. The modified functions provided excellent fits to data from six soils with textures ranging from sand to silty clay. The modified functions, as well as the function proposed by Rossi and Nimmo (1994), were combined with the Mualem conductivity model to generate closed-form analytical expressions for the calculation of hydraulic conductivity. (from Authors)
61A
962101 An evaluation of the Bouwer and Rice method of slug test analysis D. L. Brown, T. N. Narasimhan & Z. Demir, Water Resources Research, 31(5), 1995, pp 1239-1246. The method of Bouwer and Rice (1976) for analyzing slug test data is widely used to estimate hydraulic conductivity (K). Based on steady state flow assumptions, this method is specifically intended to be applicable to unconfined aquifers. Therefore it is of practical value to investigate the limits of accuracy of the K estimates obtained with this method. It was found that the estimates of K were consistently superior to those obtained with Hvorslev's (1951) basic time lag method. In general, the Bouwer and Rice method tends to underestimate K, the greatest errors occurring in the presence of a damaged zone around the well or when the top of the screen is close to the water table. (from Authors)
962102 Development and testing of active groundwater samplers B. Nilsson, R. Jakobsen & L. J. Ardcrsen, Journal of Hydrology, 171(3-4), 1995, pp 223-238. Describes two different sampling techniques: the Separation Pumping Technique (SP) and the Packer Baffle System (PBS). The methodology and design of the two systems is presented and the operational application is demonstrated by examples from full-scale field experiments. The methods are validated and their sensitivity to the well construction and the hydrogeology environment is assessed based on numerical modelling and controlled laboratory experiments. (Authors)
962103 Development and testing of multiport sock samplers for groundwater M. Schirmer, I. Jones, G. Teutsch & D. N. Lerner, Journal of Hydrology, 171(3-4), 1995, pp 239-257. The concept involves displacing the water column and sealing the borehole with a long, low-pressure packer, which can be of modular construction. Samples are brought to the surface by low-flow sampling pumps which can be located inside or outside the packer and are connected to individual ports situated at the borehole wall. Two different styles were designed, constructed and tested. The advantages and disadvantages of each system, and the concept of the multiport sock sampler are discussed. (from Authors)
962104 Field trials of active and multi-port sock samplers in gravelpacked weHs B. Nilsson, L. Luckner & M. Schirmer, Journal of Hydrology, 171(3-4), 1995, pp 259-289. Four novel sampling systems were tested for their ability to obtain level-representativc groundwater samples from two gravel-packed boreholes in different hydrogcological settings at Skrydstrup (Denmark) and Torgan (Germany). Samples obtained with the novel devices were compared with those obtained from nearby permanent dedicated reference systems. Results obtained using the novel samplers vary from excellent agreement to no agreement. The choice of the sampler depends mainly on the specific hydrogcologieal conditions, well completion, the type of pollution and the time available for sampling. (from Authors)
962105 Level-determined sampling in an uncased borehole I. Jones & D. N. Lcrner, Journal of Hydrology, 171(3-4), 1995, pp 291-317. Four novel sampling devices (two sock samplers and two active devices) were tested for their ability to obtain levelrepresentative groundwater from a 90 m uncased borehole in a Pcrmo-Triassic sandstone aquifer. The samples were compared with those taken from a nearby piezometer nest. The results from the open borehole were not consistent with those from the piezomcters, particularly in the lower part of the aquifer. A strong downward vertical head gradient caused flow into the top of the boreholc and out of the bottom,
962097 Approximate mix'ted-integer nonlinear programming methods for optimal aquifer remedintion design D. C. McKinncy & Min-Der Lin, Water Resources Research, 31(3), 1995, pp 731-740. An optimal aquifer remediation design model employing a nonlinear programming algorithm was developed to find the minimum cost design of a pump-and-treat aquifer remcdiation system. The mixed-integer nonlinear programming model includes the discontinuous fixed costs of system construction and installation as well as operation and maintenance. The polynomial penalty coefficient method results were compared to two alternatives. The polynomial penality coefficient method obtains the same solutions and performs as well as or better than the exponential penality coefficient method. It also almost always results in better, less expensive designs and requires significantly less computer time than the pseudo-integer method. (from Authors)
962098 Groundwater remediation design using a three-dimensional simulation model and mixed-integer programming C. S. Sawyer, D. P. Ahlfeld & A. J. King, Water Resources Research, 31(5), 1995, pp 1373-1385. A three-dimensional groundwater flow management model for making decisions on the design of hydrodynamic control of a groundwater fl0w system using a combination of extraction and/or injectionwells is developed. The mathematicalformulation of the groundwater remediation problem as a mixed-integer model and the strategy for solving the model arc presented. Numerical resultsare presented for the Toms River Plant site, which is modeled as a five-layer aquifer system with interconnecting aquitards. (Authors)
962099 Contaminant transport mechanisms in karst terrains and implications on remediation W. Barncr & K. Uhlman, in: Karst geohazards: engineering and environmental problems in karst terrane. Proc. 5th conference, Gatlinburg 1995, ed B.F. Beck, (Balkema), 1995, pp 207-212. Because successful implcmeptation of ground water remediation cannot be achieved without a full understanding of dissolved and non-aqueous phase transport mechanisms, the hydrogcologist must rely on developing a site conceptual model based on interpretation of field data. Investigative techniques for predicting the probable location of both lightand dense-non-aqueous phase liquid (LNAPL and DNAPL) in the flow continuum of karst aquifers are presented in this paper within the framework of ground water remcdiation options. (from Authors)
962100 Modified soil water retention functions for all matric suctions M. J. Fayer & C. S. Simmons, Water Resources Research, 31(5), 1995, pp 1233-1238. The Brooks-Corey and van Genuchten functions were modified to adequately represent retention at all matric suctions. The modification consisted of replacing the residual water content with an adsorption equation (Campbell and Shiozawa, 1992). The modified functions retain the form of the original functions in the wet range and the form of an adsorption equation in the dry range. The modified functions provided excellent fits to data from six soils with textures ranging from sand to silty clay. The modified functions, as well as the function proposed by Rossi and Nimmo (1994), were combined with the Mualem conductivity model to generate closed-form analytical expressions for the calculation of hydraulic conductivity. (from Authors)
61A
962101 An evaluation of the Bouwer and Rice method of slug test analysis D. L. Brown, T. N. Narasimhan & Z. Demir, Water Resources Research, 31(5), 1995, pp 1239-1246. The method of Bouwer and Rice (1976) for analyzing slug test data is widely used to estimate hydraulic conductivity (K). Based on steady state flow assumptions, this method is specifically intended to be applicable to unconfined aquifers. Therefore it is of practical value to investigate the limits of accuracy of the K estimates obtained with this method. It was found that the estimates of K were consistently superior to those obtained with Hvorslev's (1951) basic time lag method. In general, the Bouwer and Rice method tends to underestimate K, the greatest errors occurring in the presence of a damaged zone around the well or when the top of the screen is close to the water table. (from Authors)
962102 Development and testing of active groundwater samplers B. Nilsson, R. Jakobsen & L. J. Ardcrsen, Journal of Hydrology, 171(3-4), 1995, pp 223-238. Describes two different sampling techniques: the Separation Pumping Technique (SP) and the Packer Baffle System (PBS). The methodology and design of the two systems is presented and the operational application is demonstrated by examples from full-scale field experiments. The methods are validated and their sensitivity to the well construction and the hydrogeology environment is assessed based on numerical modelling and controlled laboratory experiments. (Authors)
962103 Development and testing of multiport sock samplers for groundwater M. Schirmer, I. Jones, G. Teutsch & D. N. Lerner, Journal of Hydrology, 171(3-4), 1995, pp 239-257. The concept involves displacing the water column and sealing the borehole with a long, low-pressure packer, which can be of modular construction. Samples are brought to the surface by low-flow sampling pumps which can be located inside or outside the packer and are connected to individual ports situated at the borehole wall. Two different styles were designed, constructed and tested. The advantages and disadvantages of each system, and the concept of the multiport sock sampler are discussed. (from Authors)
962104 Field trials of active and multi-port sock samplers in gravelpacked weHs B. Nilsson, L. Luckner & M. Schirmer, Journal of Hydrology, 171(3-4), 1995, pp 259-289. Four novel sampling systems were tested for their ability to obtain level-representativc groundwater samples from two gravel-packed boreholes in different hydrogcological settings at Skrydstrup (Denmark) and Torgan (Germany). Samples obtained with the novel devices were compared with those obtained from nearby permanent dedicated reference systems. Results obtained using the novel samplers vary from excellent agreement to no agreement. The choice of the sampler depends mainly on the specific hydrogcologieal conditions, well completion, the type of pollution and the time available for sampling. (from Authors)
962105 Level-determined sampling in an uncased borehole I. Jones & D. N. Lcrner, Journal of Hydrology, 171(3-4), 1995, pp 291-317. Four novel sampling devices (two sock samplers and two active devices) were tested for their ability to obtain levelrepresentative groundwater from a 90 m uncased borehole in a Pcrmo-Triassic sandstone aquifer. The samples were compared with those taken from a nearby piezometer nest. The results from the open borehole were not consistent with those from the piezomcters, particularly in the lower part of the aquifer. A strong downward vertical head gradient caused flow into the top of the boreholc and out of the bottom,