Studies in Australian Estuarine Hydrology. II. The Swan River

1956 ◽  
Vol 7 (2) ◽  
pp. 193 ◽  
Author(s):  
RS Spencer
Keyword(s):  
Recovery Period ◽  
River Estuary ◽  
Barometric Pressure ◽  
Tidal Mixing ◽  
Lunar Tides ◽  
Eastern Australia ◽  
Mean Water Level ◽  
Tidal Characteristics ◽  
Basin Region ◽  
Swan River

The physiography of the Swan River is described, with particular reference to the drowned valley basin which is connected to the sea across a shallow sill. The climatological features of the region are discussed, together with the tidal characteristics of the basin. Drought conditions prevail during the summer, effective rainfall being confined to the winter months. Density stratification in the basin is intense and prolonged, because of the weakly developed tidal mixing. Changes in the mean water level of the basin are correlated with variations in barometric pressure; the amplitude of these changes sometimes exceeds that of the lunar tides. This fact has a significant bearing on hydrological conditions within the basin. The distribution and the seasonal cycles of temperature, chlorinity, and oxygen saturation are compared with those of a tidal-dominated estuary situated at the same latitude In eastern Australia. Most of the differences in these cycles can be attributed to the tidal regimes of the two systems. Nutrient cycles within the Swan River basin are discussed with particular reference to the recovery period following the development of stratification. In the later stages of the investigation this period was studied intensively, and from the information obtained several theories are advanced to explain the circulatory features of the basin region. An attempt is made to classify the Swan River estuary.

scholarly journals Response of the Snowy River Estuary to two environmental flows

2015 ◽  
Vol 127 (2) ◽  
pp. 28
Author(s):  
Errol J. McLean ◽  
Jon B. Hinwood
Keyword(s):  
Fresh Water ◽  
Peak Flow ◽  
Environmental Flows ◽  
River Estuary ◽  
Environmental Flow ◽  
River Channel ◽  
Salinity Gradients ◽  
Tasman Sea ◽  
Eastern Australia ◽  
Major River

The Snowy River is a major river in south-eastern Australia, discharging to the Tasman Sea via a barrier estuary, with its entrance constricted by marine sands. Since the construction of the Snowy Mountains Scheme, river flows have not been sufficient to maintain the river channel. A program of environmental flow releases (EFR) is returning water to the river to restore the fluvial reaches and is now trialling flow regimes that may also benefit the estuarine reaches. This paper documents the response of the estuarine segments of the Snowy River to two EFRs; the release in 2010 was designed to scour the upper reaches of the Snowy River while the larger 2011 release was intended to extend the scouring downstream. For each release, the effects on the entrance morphology, tides and salinity through the flow peak and recovery are described. Each EFR caused minor increases in depth and very minor longshore movement of the entrance channel, although each EFR had been preceded by a larger fresh flow that would have scoured the channels. The small increase in fresh water inflow in the 2010 EFR pushed salinity contours seawards and steepened vertical salinity gradients. The larger inflow in the 2011 EFR purged the upper estuary of saltwater. After the peak flow, salinity recovery was rapid in the principal estuarine channels but took weeks where poorly connected wetlands could store fresh flood waters. Critical flows for scouring the entrance and purging salinity are estimated.

scholarly journals Tidal Mixing Signatures in the Hong Kong Coastal Waters from Satellite-Derived Sea Surface Temperature

2018 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
R. Susanto ◽  
Jiayi Pan ◽  
Adam Devlin
Keyword(s):  
Hong Kong ◽  
High Resolution ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coastal Waters ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Sea Surface ◽  
Tidal Mixing ◽  
Diurnal Tides

Tidal mixing in the coastal waters of Hong Kong was investigated using a combination of in situ observations and high-resolution satellite-derived sea surface temperature (SST) data. An indicator of tide-induced mixing is a fortnightly (spring-neap cycle) signature in SST due to nonlinear interactions between the two principal diurnal and the two principal semi-diurnal tides. Both semi-diurnal and diurnal tides have strong tidal amplitudes and currents near Hong Kong. As a result, both the near-fortnightly (Mf) and fortnightly (MSf) tides are enhanced due to nonlinear tidal signal interactions. In addition, these fortnightly tidal signals are modulated by seasonal variability, with the maximum seasonal modulation of fortnightly tides occurring during the monsoon transition periods in May and October. The largest fortnightly signals are found in the southwestern part of the Pearl River estuary. Tidal constituent properties vary by space and depth, and high-resolution SST plays a pivotal role in resolving the spatial characteristics of tidal mixing.

scholarly journals Artificially oxygenating the Swan River estuary increases dissolved oxygen concentrations in the water and at the sediment interface

2019 ◽  
Vol 128 ◽  
pp. 112-121 ◽  
Author(s):  
Sarah J. Larsen ◽  
Kieryn L. Kilminster ◽  
Alessandra Mantovanelli ◽  
Zoë J. Goss ◽  
Georgina C. Evans ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
River Estuary ◽  
Swan River ◽  
Sediment Interface ◽  
Oxygen Concentrations

Nutrient limitation of phytoplankton in the upper Swan River estuary, Western Australia

1996 ◽  
Vol 47 (4) ◽  
pp. 659 ◽  
Author(s):  
PA Thompson ◽  
W Hosja
Keyword(s):  
Nutrient Limitation ◽  
Chlorophyll A ◽  
Phytoplankton Community ◽  
River Estuary ◽  
Early Summer ◽  
Phosphate Silicate ◽  
Cell Densities ◽  
And Control ◽  
Swan River ◽  
Second Peak

During 1993-94 the phytoplankton community in the upper Swan River estuary had a peak chlorophyll a concentration of 57 mg m-3 during early summer (December 1993) and a second peak of 35 mg m-3 during late autumn (May 1994). Mid summer was characterized by low cell densities and low chlorophyll a concentrations. The potential of the phytoplankton community for nutrient limitation was assessed with dilution bioassays given nutrient mixes deficient in one of the following: nitrogen, phosphate, silicate, iron, trace metals, chelators, or vitamins. During the mid-summer period of low phytoplankton abundance, nitrogen was the nutrient with the greatest potential to limit algal biomass. During mid summer, ambient N:P ratios tended to be near unity and bioassays indicated that the available pool of N was up to 20 times more limiting to biomass development than was available P. Also during mid summer, bioassay treatments given no nitrogen and control treatments given no nutrients showed little growth, reaching chlorophyll a concentrations -1/30th of those given a full suite of nutrients. Chlorophyll a concentrations in the bioassay control treatments given no nutrients were correlated (r2 = 0.74) with measured surface nitrate concentrations; this suggested that nitrate inputs may be a major factor controlling phytoplankton biomass in this ecosystem. The correlation between surface nitrate concentration and rainfall (r2 = 0.69) further suggests that rainfall may be the most important mechanism supplying nitrate to the surface waters of this estuary.

Three-dimensional modelling of a Microcystis bloom event in the Swan River estuary, Western Australia

2004 ◽  
Vol 174 (1-2) ◽  
pp. 203-222 ◽  
Author(s):  
B.J. Robson ◽  
D.P. Hamilton
Keyword(s):  
Western Australia ◽  
Three Dimensional ◽  
River Estuary ◽  
Microcystis Bloom ◽  
Swan River

The hydrology of the upper Swan River Estuary with focus on an artificial destratification trial

2001 ◽  
Vol 15 (13) ◽  
pp. 2465-2480 ◽  
Author(s):  
David P. Hamilton ◽  
Terence Chan ◽  
Malcolm S. Robb ◽  
Chari B. Pattiaratchi ◽  
Michael Herzfeld
Keyword(s):  
River Estuary ◽  
Artificial Destratification ◽  
Swan River

Identifying resuspended sediment in an estuary using the 228Th/232Th activity ratio: the fate of lagoon sediment in the Bega River estuary, Australia

2000 ◽  
Vol 51 (7) ◽  
pp. 659 ◽  
Author(s):  
Gary J. Hancock
Keyword(s):  
Suspended Sediment ◽  
River Flow ◽  
Activity Ratio ◽  
Sediment Resuspension ◽  
River Estuary ◽  
Low Flow ◽  
Eastern Australia ◽  
Lagoon Sediment ◽  
Thorium Series ◽  
High River Flow

Thorium-series nuclides (228Th and 232Th) have been used to identify resuspended sediment in the Bega River estuary, south-eastern Australia. A non-conservative increase in concentration of suspended sediment of water in the vicinity of mid-estuary back-flow lagoons was associated with a decrease in the 228Th/232Th activity ratio (AR) of the suspended sediment. The lagoon sediment is characterized by a low estuarine 228Th/232Th signature, distinguishing it from freshwater suspended sediment recently delivered to the estuary, and identifying it as the likely source of the additional suspended sediment. Sediment-core 210Pb profiles show that the lagoons are accumulating sediment, presumably during high river-flow events. However this study indicates that during intervening periods of low flow, 40% of sediment deposited in the lagoons is subsequently resuspended and exported to the lower estuary, and possibly to the ocean. The utility of the 228Th/232Th AR to quantify sediment resuspension in estuaries is likely to be estuary-dependent, and is controlled by the extent of scavenging of dissolved 228Th by suspended particles.

Waders and Other Aquatic Birds on the Swan River Estuary, Western Australia

1938 ◽  
Vol 38 (1) ◽  
pp. 18-29 ◽  
Author(s):  
D. L. Serventy
Keyword(s):  
Western Australia ◽  
River Estuary ◽  
Aquatic Birds ◽  
Swan River

scholarly journals Diversity and abundance of epibiota on invasive and native estuarine gastropods depend on substratum and salinity

2015 ◽  
Vol 66 (12) ◽  
pp. 1191 ◽  
Author(s):  
Jakob Thyrring ◽  
Mads Solgaard Thomsen ◽  
Ane Kirstine Brunbjerg ◽  
Thomas Wernberg
Keyword(s):  
Environmental Factors ◽  
Native Species ◽  
Linear Models ◽  
River Estuary ◽  
Generalised Linear Models ◽  
Future Studies ◽  
Shell Type ◽  
Five Factors ◽  
Wide Scale ◽  
Swan River

Our understanding of variation in epibiota communities remains incomplete. This study relates such variability to multiple concurrent environmental factors. Specifically we determined the relative importance of salinity, depth, wave exposure, habitat and ‘shell type’ (shell type combined species, size, morphology and mobility traits) for community structure of sessile epibiota on gastropods in the Swan River Estuary, Australia. We quantified distribution, biofouling patterns, and detailed epibiota community structures on gastropod species in the estuary – the native Nassarius pauperatus and Bedeva paiva and the invasive Batillaria australis. The invasive Batillaria was much more abundant, and more biofouled, than any of the native species, thereby supporting orders of magnitude more epibiota in the estuary. Generalised linear models were used to partition variation in richness and abundance of epibiota among the above listed factors. Of the five factors were only shell type and salinity significant in 9 of 14 models. These results highlight (1) that a single invasive species can alter epibiota communities on a large system-wide scale, (2) an overwhelming importance of shell type and salinity in explaining estuarine epibiota communities, and (3) that additional environmental factors need to be included in future studies to improve predictive models of distribution for epibiota communities.

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