- Title
- Comparison of groundwater transit velocity estimates from flux theory and water table recession based approaches for solute transport
- Creator
- Rasiah, Velu; Armour, John
- Date
- 2013
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/56344
- Identifier
- vital:5392
- Identifier
-
https://doi.org/10.1016/j.jenvman.2012.11.025
- Identifier
- ISSN:0301-4797
- Abstract
- Reliable information in transit time (TT) derived from transit velocity (TV) for rain or irrigation water to mix with groundwater (GW) and the subsequent discharge to surface water bodies (SWB) is essential to address the issues associated with the transport of nutrients, particularly nitrate, from GW to SWB. The objectives of this study are to (i) compare the TV estimates obtained using flux theory-based (Fe) approach with the water table rise/recession (WT) rate approach and (ii) explore the impact of the differences on solute transport from GW to SWB. The results from a study conducted during two rainy seasons in the northeast humid tropics of Queensland, Australia, showed the TV varied in space and over time and the variations depended on the estimation procedures. The lateral TV computed using the WT approach ranged from 1.00 x 10(-3) to 2.82 x 10(-1) m/d with a mean of 6.18 x 10(-2) m/d compared with 2.90 x 10(-4) to 5.15 x 10(-2) m/d for Fr with a mean of 2.63 x 10(-2) m/d. The vertical TV ranged from 2.00 x 10(-3) to 6.02 x 10(-1) m/d with a mean of 1.28 x 10(-1) m/d for the WT compared with 6.76 x 10(-3)-1.78 m/d for the FT with a mean of 2.73 x 10(-1) m/d. These differences are attributed to the role played by different flow pathways. The bypass flow pathway played a role only in WT but not in FT. Approximately 86-95% of the variability in lateral solute transport was accounted for by the lateral TV and the total recession between two consecutive major rainfall events. A comparison of TT from FT and WT approaches indicated the laterally transported nitrate from the GW to the nearby creek was relatively 'new', implying the opportunity for accumulation and to undergo biochemical reactions in GW was low. The results indicated the WT approach produced more reliable TT estimates than FT in the presence of bypass flow pathways. (C) 2012 Elsevier Ltd. All rights reserved.; C1
- Relation
- Journal of Environmental Management Vol. 116, no. (February 2013 2013), p. 36-49
- Rights
- © 2012 Elsevier Ltd.
- Rights
- This metadata is freely available under a CCO license
- Subject
- MD Multidisciplinary; Groundwater; Transit velocity; Transit time; Water table rise/recession rates; Flux theory; Nitrate; Nitrate dynamics; Catchment; Models; Flow; Fluctuations; Tracers; Time
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