| Abstract: | A multispecies numerical code was developed to simulate flow and mass transport with kinetic adsorption in variable-density flow systems. The two-dimensional code simulated the transport of bromide (Br-), a nonreactive tracer, and lithium (Li+), a reactive tracer, in a large-scale tracer test performed in a sand-and-gravel aquifer at Cape Cod, Massachusetts. A two-fraction kinetic adsorption model was implemented to simulate the interaction of Li+ with the aquifer solids. Initial estimates for some of the transport parameters were obtained from a nonlinear least squares curve-fitting procedure, where the breakthrough curves from column experiments were matched with one-dimensional theoretical models. The numerical code successfully simulated the basic characteristics of the two plumes in the tracer test. At early times the centers of mass of Br- and Li+ sank because the two plumes were closely coupled to the density-driven velocity field. At later times the rate of downward movement in the Br- plume due to gravity slowed significantly because of dilution by dispersion. The downward movement of the Li+ plume was negligible because the two plumes moved in locally different velocity regimes, where Li+ transport was retarded relative to Br-. The maximum extent of downward transport of the Li+ plume was less than that of the Br- plume. This study also found that at early times the downward movement of a plume created by a three-dimensional source could he much more extensive than the case with a two-dimensional source having the same cross-sectional area. The observed shape of the Br- plume at Cape Cod was simulated by adding two layers with different hydraulic conductivities at shallow depth across the region. The large dispersion and asymmetrical shape of the Li+ plume were simulated by including kinetic adsorption-desorption reactions. |
| Genre: | Article |
| ProdID: | 70021026 |
| Citation Author: | Zhang, H.; Schwartz, F. W.; Wood, W. W.; Garabedian, S. P.; LeBlanc, D. R. |
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| Citation End Page: | 82 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Water Resources Research |
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| Citation Number Of Pages: | 16 |
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| Citation Search Results Text: | Simulation of variable-density flow and transport of reactive and nonreactive solutes during a tracer test at Cape Cod, Massachusetts; 1998; Article; Journal; Water Resources Research; Zhang, H.; Schwartz, F. W.; Wood, W. W.; Garabedian, S. P.; LeBlanc, D. R. |
| Citation Start Page: | 67 |
| Citation Volume: | 34 |
| Citation Year: | 1998 |
| Type: | citation/reference |
| Text: | Simulation of variable-density flow and transport of reactive and nonreactive solutes during a tracer test at Cape Cod, Massachusetts; 1998; Article; Journal; Water Resources Research; Zhang, H.; Schwartz, F. W.; Wood, W. W.; Garabedian, S. P.; LeBlanc, D. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Thu, 1 Jan 1998 00:00 -0600 |
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