Prolonged river water pollution due to variable-density flow and solute transport in the riverbed

Jin, Guangqiu, Tang, Hongwu, Li, Ling and Barry, D. A. (2015) Prolonged river water pollution due to variable-density flow and solute transport in the riverbed. Water Resources Research, 51 4: 1898-1915. doi:10.1002/2014WR016369

Author Jin, Guangqiu
Tang, Hongwu
Li, Ling
Barry, D. A.
Title Prolonged river water pollution due to variable-density flow and solute transport in the riverbed
Journal name Water Resources Research   Check publisher's open access policy
ISSN 0043-1397
Publication date 2015
Year available 2015
Sub-type Article (original research)
DOI 10.1002/2014WR016369
Open Access Status
Volume 51
Issue 4
Start page 1898
End page 1915
Total pages 18
Place of publication Hoboken, NJ United States
Publisher Blackwell Publishing
Collection year 2015
Language eng
Subject 2312 Water Science and Technology
Formatted abstract
A laboratory experiment and numerical modeling were used to examine effects of density gradients on hyporheic flow and solute transport under the condition of a solute pulse input to a river with regular bed forms. Relatively low-density gradients due to an initial salt pulse concentration of 1.55 kg m−3 applied in the experiment were found to modulate significantly the pore-water flow and solute transport in the riverbed. Such density gradients increased downward flow and solute transport in the riverbed by factors up to 1.6. This resulted in a 12.2% increase in the total salt transfer from the water column to the riverbed over the salt pulse period. As the solute pulse passed, the effect of the density gradients reversed, slowing down the release of the solute back to the river water by a factor of 3.7. Numerical modeling indicated that these density effects intensified as salt concentrations in the water column increased. Simulations further showed that the density gradients might even lead to unstable flow and result in solute fingers in the bed of large bed forms. The slow release of solute from the bed back to the river led to a long tail of solute concentration in the river water. These findings have implications for assessment of impact of pollution events on river systems, in particular, long-term effects on both the river water and riverbed due to the hyporheic exchange.
Keyword Fingers
Hyporheic exchange
Pollution incident
River water quality
Solute transport
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
Official 2016 Collection
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