Effects of a gradient in river regulation on the longitudinal trends in water quality and benthic algal and macroinvertebrate assemblages in the Hunter River, Australia

2012 ◽  
Vol 63 (6) ◽  
pp. 494 ◽  
Author(s):  
Daniela P. Cortez ◽  
Ivor O. Growns ◽  
Simon M. Mitrovic ◽  
Richard P. Lim

River regulation impacts lotic ecosystem processes; however, the effect of a gradient of regulation on these attributes has rarely been studied. This study examined the effects of a river regulation gradient on longitudinal trends in water quality and benthic algal and macroinvertebrate assemblages in three tributaries of the Hunter River, New South Wales, Australia. Longitudinal patterns were expected to differ across rivers, with recovery being proportional to its regulation gradient. Significant differences in longitudinal trends were tested using permutational multivariate analysis of variance (PERMANOVA) through exploration of the river by distance from source interaction. Multi-dimensional scaling (MDS) ordination plots identified sites responsible for any significant interaction observed. Similarity percentage analysis (SIMPER) analyses identified variables/taxa responsible for differences at sites below dams. BEST analyses identified environmental variables best explaining biological assemblage patterns. Significant differences in longitudinal trends were observed for all attributes. Increases in the regulation gradient most affected macroinvertebrate assemblages, followed by water quality and benthic algal assemblages respectively. Downstream recovery was absent in the heavily regulated river at its most downstream site, whereas recovery was observed on corresponding sites of the moderately regulated river. The study suggests that a gradient in river regulation increases the magnitude of disruption of lotic ecosystems, with recovery dependent on this gradient.

2020 ◽  
Vol 24 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Fidelis Godfrey Jaravani ◽  
Michelle Butler ◽  
Paul Byleveld ◽  
David N. Durrheim ◽  
Peter. D. Massey ◽  
...  

1998 ◽  
Vol 49 (3) ◽  
pp. 241 ◽  
Author(s):  
A. J. Underwood ◽  
M. G. Chapman

Data were collected in New South Wales from replicate sites on five wave-exposed shores separated by hundreds of kilometres at three-monthly intervals for four years, to examine large and small spatial and temporal patterns in low-shore algal assemblages. These data were used to test hypotheses from the models that algal assemblages show large-scale, predictable changes in structure or, alternatively, that variation from time to time is small-scale and differs from shore to shore or site to site on a shore. There was considerable variation at all scales examined — among replicate quadrats within sites, between sites on a shore and among shores. Similarly, assemblages differed from one sampling period to the next and changes in the assemblages over time periods of three months were as great as from year to year. These changes were interactive, with no two sites or shores showing similar temporal patterns. Thus, understanding diversity along a coast-line requires detailed understanding of local processes. Without adequate spatial and temporal replication in sampling designs and without explanatory models, the large and complex variability in intertidal assemblages at different scales cannot be documented and understood.


1989 ◽  
Vol 21 (2) ◽  
pp. 141-145
Author(s):  
A. G. Bernard

The increasing popularity in the use of spa pools during the 1970's and 1980's and the accompanying incidents of folliculitis and ear infections caused by Pseudomonas aeruginosa associated with spa-pool use has necessitated the development of bacteriological and chemical guidelines for spa-pool water quality. The New South Wales (N.S.W.) Department of Health introduced a bacteriological standard for swimming pools and spa-pools in 1981 based on the findings of a series of surveys aimed at identifying the principal factors influencing the bacteriological quality of spa waters. Four surveys are summarised in this paper. The major findings described are the tenfold higher recovery of P. aeruginosa from spa-pools than from outdoor pools; the need for at least 2.0 milligrams per litre (mg/L) free chlorine residual in order to achieve reliable satisfactory water quality in spas compared with a requirement of 1.0mg/L to achieve the same quality in outdoor pools; the need to maintain pH below 8.0 in order to ensure efficient chlorine disinfection; the apparent inability of bromochlorodimethylhydantoin to adequately disinfect spas during heavy bather load periods; and the success of the Health Department's spa-pool operator education program which resulted in a 30% reduction in the incidence of bacteriologically unsatisfactory spa-pool waters in N.S.W. between 1980 and 1986.


Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 639 ◽  
Author(s):  
William Glamore ◽  
Buddhima Indraratna

A 2-stage flood estimation and water quality decision support tool (DST) was developed, calibrated, and applied to a field site in south-eastern New South Wales (NSW) to simulate tidal restoration in a flood mitigation drain affected by acid sulfate soils leachate. The first stage of the DST employs a digital terrain map, geographic information tools, and measured water levels to calculate drain water overtopping due to tidal variations. Simulations using the GIS technique at the study site indicated that the primary drainage network can safely contain full tidal flushing (0.91 m AHD or a 58% increase), whereas at the same level the secondary drainage network overtops along relict drainage channels. The second stage of the DST simulates the change in drain water quality using an ion-specific program code written within the open interface PHREEQC program. The results from the water quality model were calibrated against laboratory titration tests. Drain water pH was shown to increase above 6.0, and soluble aluminium and iron concentrations decreased by 73% and 56%, respectively. The extent of water quality change is directly related to the ionic strength of the intruding water and the ion-specific reaction kinetics of aluminium, iron, and sulfate.


2003 ◽  
Vol 54 (6) ◽  
pp. 691 ◽  
Author(s):  
Nicole A. Hill ◽  
Craig Blount ◽  
Alistair G. B. Poore ◽  
Duncan Worthington ◽  
Peter D. Steinberg

The sea urchin Centrostephanus rodgersii plays an important role in determining the abundance and composition of benthic macroalgae in New South Wales. Centrostephanus rodgersii is commonly found in areas devoid of foliose algae (termed 'barrens habitat'), which abruptly change into areas rich in foliose algae (termed 'fringe habitat'). Complementary experiments were used to investigate the impact of C. rodgersii grazing on algal assemblages at a range of densities in the barrens and fringe habitats. Although 33% of the natural density of C.�rodgersii maintained barrens areas relatively free of foliose algae, only densities exceeding natural densities within barrens habitat cleared areas dominated by macroalgae. The impact of grazing was not linearly related to density in either habitat, which suggests that both the barrens and fringe habitats are stable and will persist unless there is a dramatic decrease in urchin densities in barrens areas or a large influx into fringe areas. These findings have significant implications for the commercial harvesting of C. rodgersii. They imply that reducing urchin densities in barrens habitats, or translocating urchins from barrens to fringe habitats in order to improve roe quality, will not significantly alter the algal assemblage of either habitat in the short term (less than 3 months).


2019 ◽  
Vol 68 (8) ◽  
pp. 708-717 ◽  
Author(s):  
S. T. M. L. D. Senevirathna ◽  
Andrea M. Goncher ◽  
Aaron Hollier

Abstract There is a substantial research gap relating to the quality of drinking water in regional Australia and identifying possible improvements. In particular, the quality of water available in public places (washing and drinking), such as water bubblers installed in regional parks, schools, rest areas and railway stations, is poorly investigated. This paper discusses the primary and secondary water quality of eight water distribution networks in New South Wales (NSW) regional towns. An analysis of a large number of drinking water samples (more than 11,000) identified that maintaining microbial water quality and the required free chlorine level (>0.2 mg/L) are challenging issues for regional water distribution networks. Sixty-three per cent of the samples collected from the water outlets available in public places of a regional town showed free chlorine levels of <0.2 mg/L, and 30% of samples showed positive results for total coliform. All heavy metal levels of the samples were within the safe level. Water temperature was identified as the most problematic secondary water quality parameter in public water bubblers. Stainless steel was the common material used in bubblers where surface temperatures exceeded 50 °C during summer. This study identifies possible design and operational modifications to improve regional drinking water quality and make public water bubblers more usable.


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