- Email: [email protected]
Unsteady finite-analytic method for solute transport in groundwater flow
HYDROGEOLOGY:PHYSICO-CHEMICAL
CHANGES
259A
956063 Regional-scale ground water quality monitoring via integer programming P. F. Hudak, H. A. Loaiciga & M. A. Marino, Journal of Hydrology, 164(1-4), 1995, pp 153-170.
956067 When enough is enough the worth of moaitoriag data in aquifer remediatioa design B. R. James & S. M. Gorelick, Water Resources Research, 30(12), 1994, pp 3499-3513.
A network design approach developed in this paper identifies monitoring sites in multi-layered, regional ground water flow systems at risk of contamination from waste storage facilities. Candidate locations are assigned weights that quantify monitoring value in terms of the prospect of plume detection and exposure hazard criteria. The model selects well sites that are close together near the source of contamination, facilitating early detection of a contaminant release, and further apart downgradient, resulting in areal coverage for plume characterixation. (from Authors)
Given the high cost of data wlleetion at groundwater wntamination remediation sites, it is becoming hmreasingly important to make data collection as cost-effeotive as possible. A Bayesian data worth framework is developed in an attempt to carry out this task for remediation programs in which a groundwater contaminant plume must be located and then hydraulically contained. The framework is applied to a hypothetical wntam.ination problem where tmwrtamty in plume location and extent are caused by uncertainty in source location, source loading time, and aquifer heterogeneity. (from Authors)
956064 Unsteady fir&e-aallytic method for solute transport in groundwater flow Whey-Fone Tsai & Ching-Jen Chen, Journal of Engineering Mechanics - AXE, 121(2), 1995, pp 230-243.
Chemical and physical changes due to water
Tbis work illustrates the development and application of the unsteady finite-analytic (FA) numerical solution for the migration of ground-water contamination. A functional/ optimal time-weighting factor is proposed for the expression of the unsteady term in the solute-transport equation. In the examples, the performance of unsteady FA numerical solutions is demonstrated by simulating the solute transport emitting from a Gaussian-line source. It is shown that the use of the functional time-weighting factor associated with the finite-analytic method appears to be a better choice for avoiding numerical diffusions and oscillations than, through comparison with, the fully implicit (time-weighting factor = 0) and the Crank-Nicholson (time-weighting factor = 0.5) FA schemes. (Authors)
956065 RadionucBde migration us@ a travel time transport approach and its application in risk analysis R. Andriwvic, J. I. Daniels & R. L. Jacobson, Journal of Hydrology, 163(1-2), 1994, pp 125-145. The travel time transport approach for radioactive elements undergoing sorption and decay is employed in assessing the potential health risk at possible locations of human receptors. The principal entity in approach presented is a travel time probability density function conditioned on the set of parameters used to describe different transport processes, like advection, dispersion, sorption, and decay. The importance of accounting for parameter uncertainty and possible correlation between them is described and demonstrated in the study of risk analysis at the Nevada Test Site. The results from the risk-based screening analysis suggest that tritium is responsible for about 90% of the total risk. (from Authors)
956066 Siiulation of surfactantsnkanced aquifer remediation C. L. Brown, G. A. Pope, L. M. Abriola & K. Sepehmoori, Water Resources Research, 30(11), 1994, pp 2959-2977. Surfactant-enhanced aquifer remediation (SEAR) is currently under active investigation as one of the most promising alternatives to conventional pump-and-treat remediation for aquifers wntaminated by dense nonaqueous phase organic liquids. An existing three-dimensional finite-difference enhanced oil recovery simulator is adapted to model the SEAR process. Simulations suggest that the total time for remediation could be reduced by more than an order of magnitude over conventional remediation approaches by employing SEAR. (from Authors)
Simulating solute transport ia aa aggregated soil with the
dual-porosity model: measured and optimized parameter values M. L. Bmsseau, Z. Gerstl, D. Augustijn & P. S. C. Rao, Journal of Hyciiology, 163(1-2), 1994, pp 187-193. The capability of the first-order, dual-porosity model, which explicitly accounts for non-ideal transport caused by the presence of ‘immobile’ water, to predict the non-ideal transport of non-sorbing solute in a wnstructed aggregated soil bas been investigated. Miscible-displacement experiments performed with a well-chara&r&d aggregated soil and a non-reactive tracer served as the source of the data. The calculated and optimixed values compared well, suggesting that the non-equilibrium parameters represent actual physical phenomena. (from Authors) 9!%069 Oil migration through onsaturated sob aml its effect on tbe vadose zone interactive processes (VIP) model output A. T. Joseph, W. J. Grenney ik D. K. Stevens, Water Science & Technology, 30(3), 1994, pp 39-51. A mathematical model called the Vadose Zone Interactive Processes (VIP) model was developed and implemented at Utah State University (USU) for evaluating the fate of hazardous substances in the unsaturated xone of the soil during land treatment of oily wastes. The VIP model, which simulates the wncentration profdes of the hazardous wmpounds in the soil, water, and the air phases, assumes a fixed only phase. The purpose of this study was to measure oil migration in soil systems and to determine its effect on the W model output. The experiments demonstrated that oil migrates down significantly througb the soil columns. The extent of migration depended on the volume of oil applied and the type of soil. However, the applied oil was wmpletely immobilized in the wlumns. The VIP model was modiSed to incorporate oil migration. The modified VIP model can be expeeted to produce more realistic wntaminant concentration profiles during land treatment of oily wastes when compared to that produced by the present version of the VIP model. (Authors) 956070
Preliminary results from a field experiment investigating the fate of some creosote compoaenta in a natural aqldfer M. G. Fowler, P. W. Brooks, M. Northwtt, M. W. G. King, J. F. Barker & L. R. Snowdon, Organic Geochemirtry, 22(35), 1994, pp 641649.
CHANGES
259A
956063 Regional-scale ground water quality monitoring via integer programming P. F. Hudak, H. A. Loaiciga & M. A. Marino, Journal of Hydrology, 164(1-4), 1995, pp 153-170.
956067 When enough is enough the worth of moaitoriag data in aquifer remediatioa design B. R. James & S. M. Gorelick, Water Resources Research, 30(12), 1994, pp 3499-3513.
A network design approach developed in this paper identifies monitoring sites in multi-layered, regional ground water flow systems at risk of contamination from waste storage facilities. Candidate locations are assigned weights that quantify monitoring value in terms of the prospect of plume detection and exposure hazard criteria. The model selects well sites that are close together near the source of contamination, facilitating early detection of a contaminant release, and further apart downgradient, resulting in areal coverage for plume characterixation. (from Authors)
Given the high cost of data wlleetion at groundwater wntamination remediation sites, it is becoming hmreasingly important to make data collection as cost-effeotive as possible. A Bayesian data worth framework is developed in an attempt to carry out this task for remediation programs in which a groundwater contaminant plume must be located and then hydraulically contained. The framework is applied to a hypothetical wntam.ination problem where tmwrtamty in plume location and extent are caused by uncertainty in source location, source loading time, and aquifer heterogeneity. (from Authors)
956064 Unsteady fir&e-aallytic method for solute transport in groundwater flow Whey-Fone Tsai & Ching-Jen Chen, Journal of Engineering Mechanics - AXE, 121(2), 1995, pp 230-243.
Chemical and physical changes due to water
Tbis work illustrates the development and application of the unsteady finite-analytic (FA) numerical solution for the migration of ground-water contamination. A functional/ optimal time-weighting factor is proposed for the expression of the unsteady term in the solute-transport equation. In the examples, the performance of unsteady FA numerical solutions is demonstrated by simulating the solute transport emitting from a Gaussian-line source. It is shown that the use of the functional time-weighting factor associated with the finite-analytic method appears to be a better choice for avoiding numerical diffusions and oscillations than, through comparison with, the fully implicit (time-weighting factor = 0) and the Crank-Nicholson (time-weighting factor = 0.5) FA schemes. (Authors)
956065 RadionucBde migration us@ a travel time transport approach and its application in risk analysis R. Andriwvic, J. I. Daniels & R. L. Jacobson, Journal of Hydrology, 163(1-2), 1994, pp 125-145. The travel time transport approach for radioactive elements undergoing sorption and decay is employed in assessing the potential health risk at possible locations of human receptors. The principal entity in approach presented is a travel time probability density function conditioned on the set of parameters used to describe different transport processes, like advection, dispersion, sorption, and decay. The importance of accounting for parameter uncertainty and possible correlation between them is described and demonstrated in the study of risk analysis at the Nevada Test Site. The results from the risk-based screening analysis suggest that tritium is responsible for about 90% of the total risk. (from Authors)
956066 Siiulation of surfactantsnkanced aquifer remediation C. L. Brown, G. A. Pope, L. M. Abriola & K. Sepehmoori, Water Resources Research, 30(11), 1994, pp 2959-2977. Surfactant-enhanced aquifer remediation (SEAR) is currently under active investigation as one of the most promising alternatives to conventional pump-and-treat remediation for aquifers wntaminated by dense nonaqueous phase organic liquids. An existing three-dimensional finite-difference enhanced oil recovery simulator is adapted to model the SEAR process. Simulations suggest that the total time for remediation could be reduced by more than an order of magnitude over conventional remediation approaches by employing SEAR. (from Authors)
Simulating solute transport ia aa aggregated soil with the
dual-porosity model: measured and optimized parameter values M. L. Bmsseau, Z. Gerstl, D. Augustijn & P. S. C. Rao, Journal of Hyciiology, 163(1-2), 1994, pp 187-193. The capability of the first-order, dual-porosity model, which explicitly accounts for non-ideal transport caused by the presence of ‘immobile’ water, to predict the non-ideal transport of non-sorbing solute in a wnstructed aggregated soil bas been investigated. Miscible-displacement experiments performed with a well-chara&r&d aggregated soil and a non-reactive tracer served as the source of the data. The calculated and optimixed values compared well, suggesting that the non-equilibrium parameters represent actual physical phenomena. (from Authors) 9!%069 Oil migration through onsaturated sob aml its effect on tbe vadose zone interactive processes (VIP) model output A. T. Joseph, W. J. Grenney ik D. K. Stevens, Water Science & Technology, 30(3), 1994, pp 39-51. A mathematical model called the Vadose Zone Interactive Processes (VIP) model was developed and implemented at Utah State University (USU) for evaluating the fate of hazardous substances in the unsaturated xone of the soil during land treatment of oily wastes. The VIP model, which simulates the wncentration profdes of the hazardous wmpounds in the soil, water, and the air phases, assumes a fixed only phase. The purpose of this study was to measure oil migration in soil systems and to determine its effect on the W model output. The experiments demonstrated that oil migrates down significantly througb the soil columns. The extent of migration depended on the volume of oil applied and the type of soil. However, the applied oil was wmpletely immobilized in the wlumns. The VIP model was modiSed to incorporate oil migration. The modified VIP model can be expeeted to produce more realistic wntaminant concentration profiles during land treatment of oily wastes when compared to that produced by the present version of the VIP model. (Authors) 956070
Preliminary results from a field experiment investigating the fate of some creosote compoaenta in a natural aqldfer M. G. Fowler, P. W. Brooks, M. Northwtt, M. W. G. King, J. F. Barker & L. R. Snowdon, Organic Geochemirtry, 22(35), 1994, pp 641649.