DOI: 10.5194/hess-18-1397-2014
Scopus记录号: 2-s2.0-84898490673
论文题名: Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia
作者: Bruce L ; C ; , Cook P ; L ; M ; , Teakle I ; , Hipsey M ; R
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2014
卷: 18, 期: 4 起始页码: 1397
结束页码: 1411
语种: 英语
Scopus关键词: Biogeochemistry
; Dynamics
; Hydrodynamics
; Models
; Oxygen
; Risk perception
; Rivers
; Three dimensional computer graphics
; Water quality
; Ecological health
; Effect of temperature
; Hydrodynamic control
; Morphological features
; Spatiotemporal patterns
; Statistical modeling
; Transient patterns
; Yarra river estuaries
; Estuaries
; estuarine chemistry
; hydrodynamics
; oxygen
; river flow
; salinity
; shallow water
; spatiotemporal analysis
; statistical analysis
; water quality
; Australia
; Victoria [Australia]
; Yarra River [Victoria]
英文摘要: Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical-biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic-biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate warming scenarios highlighted that oxygen depletion is likely to be exacerbated through changes in flow regimes and warming temperatures; however, the increasing risk of hypoxia and anoxia can be mitigated through management of minimum flow allocations and targeted reductions in organic matter loading. A simple statistical model (R2 > 0.65) is suggested to relate riverine flow and temperature to the extent of estuary-wide anoxia. © 2014 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78272
Appears in Collections: 气候变化事实与影响
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作者单位: School of Earth and Environment, University of Western Australia, Crawley, WA 6009, Australia; Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia; Water Studies Centre, School of Chemistry, Monash University, Monash, VIC 3800, Australia; BMT WBM Pty Ltd, Spring Hill, QLD 4000, Australia
Recommended Citation:
Bruce L,C,, Cook P,et al. Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia[J]. Hydrology and Earth System Sciences,2014-01-01,18(4)