Academic literature on the topic 'Fitzroy River (Queensland)'

Environmental Context. The Fitzroy River Basin constitutes a major source of suspended sediment and nutrient fluxes to the southern Great Barrier Reef. Improved land management practices to ameliorate these catchment loads require an understanding of the sediment sources and dynamics. This multidisciplinary geochemical and modelling study provides for the first time a quantitative estimate of sediment sources delivered to, and their degree of retention in, the Fitzroy River Estuary. Abstract. Sources of sediment deposited in the Fitzroy River Estuary (FRE) have been identified and quantified using an integrated geochemical, modelling and reconnaissance soil sampling approach. A companion paper (this volume) identifies the major sources of sediments in impoundments on the major river systems and sediment sampled from flood events in the Fitzroy River Basin (FRB). Sediment within the FRE may display distinct longitudinal variation with little basaltic material retained. Sediments derived from the Bowen Basin, which occupies the greatest portion of the FRB, and from the Surat Basin display the greatest longitudinal variation. All FRB soils have a similar total phosphorus (P) concentration. Thus, in considering P export from the catchment it is the total sediment flux which is of major importance, rather than the relative proportions of individual catchment soils. This research provides crucial new regional scale information on the sediment sources deposited within the FRE.

Environmental Context. The Fitzroy River Basin is a major contributor to the loads of suspended sediment and nutrients reaching coastal areas in the southern Great Barrier Reef. Cost-effective investment in improved land, vegetation, and water management to lower these loads requires an understanding of the sources and movement of sediments within the basin. This multidisciplinary geochemical and modelling study provides for the first time a quantitative estimate of sediment sources and spatial and hydrology-related variation within the Fitzroy River Basin. Abstract. An integrated geochemical, modelling, and reconnaissance soil sampling approach has been used to identify the sources of sediment in the Fitzroy River Basin (FRB). The composition of sediment in weirs and dams within the FRB indicate that in the southern and central FRB the Dawson River contributes only a small basaltic component and the inputs are dominated by soils from the Surat and Bowen Basins. Rivers from the central FRB carry variable amounts of basaltic soils. In contrast, basaltic soils constitute the majority of sediment transported during flood events. Surat Basin soils form a minor component of flood events with little contribution from soils of the Bowen Basin despite it constituting the majority of the area of the central FRB. Soils from the Thomson Fold Belt constitute a substantial proportion of the sediment transported by, and retained in, impoundments in the central FRB and also dominate sediment delivered from the western FRB. This study will inform cost-effective investment by government to target remedial actions to reduce sediment and nutrient loads within the FRB that may be ultimately transported via the Fitzroy River Estuary to the southern Great Barrier Reef.

Environmental context. During flood events, the Fitzroy River is a major contributor to the loads of suspended sediment and nutrients to the southern Great Barrier Reef. The present geochemical and modelling study provides for the first time a quantitative estimate of the temporal variation in sediment sources over an entire flood hydrograph. Basaltic soils are substantially enriched in this flood event relative to their catchment abundance. Abstract. Suspended sediment collected over a complete flood hydrograph in the Fitzroy River provided an insight into the origin and transport of sediment in this system. Strong temporal trends are evident in the proportions of catchment soil types estimated using a Bayesian mixing model in the fine (<10 μm) fraction of the suspended sediment. These temporal trends were also manifested in changes in mineralogy, major and trace element and Nd–Sr and C–N isotope geochemistry. Tertiary Basaltic soils were the most abundant catchment soil type transported in the flood event studied here, constituting 39% of the <10-μm sediment fraction, but varied between an estimated 20 and 50% of the suspended solids over the course of the flood event. The techniques used here allow quantification and comparison between flow and suspended sediment sources and are widely applicable to other river systems.

Understanding spatial patterns in demographic parameters of exploited fish species is of critical importance to effective fisheries management. In the present study, patterns in demography of a large, protandrous, estuarine teleost, king threadfin, Polydactylus macrochir, were compared among three estuaries on the eastern coast of Queensland, Australia. Significant variation in age and growth was observed between fish from the Fitzroy River and those from the Mary and Brisbane Rivers, with Fitzroy River fish living longer (22 years v. 10 and 14 years, respectively), reaching a greater asymptotic length (1222-mm fork length (FL) v. 975- and 1047-mm FL, respectively), and attaining greater length-at-ages of 6 years and beyond. No difference in growth was detected between Mary and Brisbane River fish, or in total mortality among any of the sites. Fitzroy River fish were generally found to mature and change sex at greater lengths and ages than those from the Mary and Brisbane Rivers. The observed variability suggests that spatially segregated populations of P. macrochir may respond differently to fishing pressure and highlights the importance of understanding the spatial patterns in demography of exploited estuarine fish populations.

Environmental context. The Fitzroy River Basin is a major source of suspended sediment and nutrients to the southern Great Barrier Reef lagoon. A reduction in sediment and nutrient loads is necessary to protect coastal reefs and this requires an understanding of the sediment sources. The present geochemical and modelling study provides a quantitative estimate of the spatial and temporal variations in the sources of sediment deposited in the Fitzroy River coastal zone. Abstract. Sediment sources to the Fitzroy River coastal zone have been identified and quantified using an integrated geochemical and modelling approach. The coastal sediments display little geochemical variation as a result of substantial homogenisation during hydrodynamic processes and indicate a sediment composition consistent with derivation from mixed catchment sources. A lack of substantial temporal geochemical variation in the sediment records indicates weathering regimes and hydrodynamic transport have been relatively consistent throughout the Holocene. Despite this apparent geochemical homogeneity, a modelling approach using a Bayesian statistical model revealed changes in catchment sediment sources over time. Variations in the occurrence and intensity of rainfall events in different parts of the catchment as well as land-use changes following European settlement are likely to have had a substantial effect on the relative contributions of the catchment sources delivered to and deposited in the coastal zone. Additionally, large variations in flow events and variable estuary hydrodynamics result in different catchment soil types being delivered and deposited under different conditions. The present study found that basaltic material is the dominant catchment source in the coastal surface sediments with an estimated enrichment of ~3 relative to catchment and estuary abundances. Basaltic soils present as a more recent and extensive, weathered surficial cover are more readily mobilised than other catchment soils and will be transported further within freshwater flood plumes. It is likely that in large flood events, this basaltic material may reach the coral-dominated outer shelf. Improved land management practices to reduce sediment loads can be targeted to the areas supplying the majority of sediment to the coastal zone.

In tropical Australia, intensive studies of river suspended sediment (SS) and nutrient dynamics have been restricted to streams on the north-east coast between the Fitzroy and Normanby Rivers (Queensland), Magela Creek/East Alligator River (Northern Territory) and the Ord River (Western Australia). Historical conditions in these rivers were probably characterised by low–moderate SS concentrations and low concentrations of dissolved inorganic nitrogen and phosphorus in flow events. Introduction of agriculture has transformed SS and nutrient dynamics. Grazing has led to soil erosion and increased SS and particulate nutrient concentrations and fluxes in event flows. Fertilised cropping has increased nutrient inputs to catchments, where it forms a substantial proportion of the catchment area. Consequently, both particulate and dissolved inorganic nutrient concentrations and fluxes have increased. Australian tropical rivers have episodic flows, with most material transport occurring during large flow events. The restricted period of these highly energetic flows means little trapping of materials in waterways occurs. Loads are transported efficiently downstream and processes such as denitrification and in-channel sedimentation may be of limited importance. Owing to excessive nutrient inputs associated with agriculture, a number of northern freshwater, estuarine and coastal ecosystems are now eutrophic. Continued development, especially fertilised cropping, without adequate management of nutrient losses is likely to exacerbate these problems.

The Burnett River snapping turtle (Elseya sp.) from the Burnett, Mary and Fitzroy river systems is an undescribed Australian freshwater turtle, of which very little ecological information is known. This paper describes the dietary ecology of the species in the Burnett River catchment. Stomach and faecal samples were collected from turtles and an index of relative importance was used to rank food items found in stomach samples. This index indicated that algae and aquatic ribbon weed (Vallisneria) were the dominant food items consumed. No difference in diet was found between males and females. Although the sample size was small, diet appeared to vary slightly seasonally, with Elseya sp. selectively feeding on the flower buds of the Chinese elm tree (Celtis chinensis) and the seeds of the blackbean tree (Castanospermum australe) when these food items were seasonally available. Faecal samples suggest that the most ingested foods (algae and aquatic ribbon weed) were also the most digestible. Although predominantly herbivorous, Elseya sp. was seen to eat carrion once in the wild.

The knowledge and understanding of sediment transport is essential for the development of effective management strategies for nutrient and sediment loading in estuarine systems. Estuarine suspended sediment (in high concentrations), has the ability to adversely impact upon surrounding ecosystems, such as the Great Barrier Reef, Australia. Due to a recent decline in water and sediment quality, it has recently been mandated that a number of tropical, coastal estuarine systems in Queensland, such as the Fitzroy River estuary, have their sediment loading reduced. In order to meet these requirements, a greater understanding of the sediment transport dynamics and driving processes (such as flocculation and settling velocity) needs to be achieved, and the accuracy of estimation improved. This research project was motivated by the need to improve the general accuracy of field measurements for estuarine suspended sediment transport and dynamics. Field-based measurements (especially settling velocity) are necessary for the parameterisation of sediment transport models. The difficulty in obtaining accurate, in situ data is well documented and is generally limited to methods that isolate a water sample from its natural environment, removing all influences of estuarine turbulence. Furthermore, the water samples are often extracted from points (Eulerian) where the history of the suspended particles is generally unknown. These sampling methods typically contain intrinsic errors as suspended sediment transport is essentially Lagrangian (i.e., flows with the net motion of flow-field) in nature. An investigation into different drogue systems conducted in parallel with a study into the tidal states of the Fitzroy River estuary led to the development of a novel Lagrangian drogue device, the LAD. Additionally, the water-tracking ability of the LAD was tested and found to accurately follow a parcel of estuarine water over a slack water period. Therefore the LAD was deployed in the Fitzroy River to assist in the further understanding of complex sediment transport processes such as flocculation and settling velocity in a natural estuarine flow field. The final device (the LAD - Lagrangian Acoustic Drogue) was developed, utilizing the principals of acoustic backscatter intensity-derived SSC measurements. The investigation of a series LAD deployments (during slack water) in the Fitzroy River estuary, revealed the dominant suspended sediment processes and also gave an insight into the prevailing flow-patterns. Results showed the presence of a settling lag mechanism between low and high tide, which can initiate a net sediment flow upstream with each flood tide. The bulk settling velocity showed comparable results at both low and high water. The LAD derived bulk settling velocity as a function of concentration (SSC), yielding a strong positive correlation (r2 = 0.73). Also the importance of flocculation in the bulk settling and clear up of the water column during periods of still water (high and low tide) was demonstrated as all in situ settling velocities (0.33 - 1.75 mm s-1) exceeded single grain approximations (0.47 mm s-1). This research demonstrates the potential for Lagrangian drogue studies as an effective measuring platform for the accurate quantification of estuarine suspended sediment dynamics. The application of the LAD in the Fitzroy River has lead to a significant improvement in the understanding of the system's real sediment transport processes. This research has provided an effective and accurate technique for measuring real settling velocities for input into numerical models or for the validation of existing model outputs. Furthermore, this technique shows great potential for application in other estuarine systems.

Land use practices over the last 200 years have dramatically altered the distribution and amount of riparian vegetation throughout many catchments in Australia. This has lead to a number of negative impacts including a decrease in water quality, an increase in sediment transport and a decrease in the quality of terrestrial and aquatic habitats. The task of restoring the functions of riparian zones is an enormous one and requires spatial and temporal prioritisation. An analysis of the existing and historical functions of riparian zones and their spatial distribution is a major aid to this process and will enable efficient use of remediation resources. The approach developed in this thesis combines remote sensing, field measurement and terrain analysis to describe the distribution of five riparian zone functions: sediment trapping, bank stabilization, denitrification, stream shading and large woody debris production throughout a large semi-arid catchment in central Queensland.

The seasonal periodicity of hydrology, physical and chemical water quality parameters and phytoplanktonic assemblages was studied at two sites in a large tropical Australian riverine impoundment. This study, the first in the lower Fitzroy River at Rockhampton, occurred between August 1990 and November 1993. It covered extremes in riverine flow conditions including major flooding and drought.

The annual flow regime was characterized by major flows in the "wet" season (summer and autumn) and greatly reduced or no flow in the "dry" season of winter, spring and sometimes early summer. Consequently, the thermal regime at both of the study sites was divided into two phases. The first was a phase of water column heating in the late winter to early summer. Features of this heating phase were long term stratification with progressive epilimnetic deepening, high pH, regular occurrence of epilimnetic oxygen supersaturation and decreased or undetectable levels of oxidized nitrogen in the surface layer. Hypolimnetic anoxia was recorded late in this phase. The second, between substantial wet season inflows and late winter was characterized by nutrient rich inflows and water column cooling and mixing.

Distinct interannual differences occurred in the volume, source and timing of inflows and subsequent water chemistry. In 1991, conductivity, water clarity, filterable reactive phosphorus (FRP) and pH increased markedly following major flooding from northern tributaries, while oxidized nitrogen decreased. This was in marked contrast to the drier years of 1992 and 1993 where turbidity and oxidized nitrogen were higher during the initial post-flood period and conductivity and FRP were lower. Extremes of mostly abiogenic turbidity (range 1.6 to 159 NTU) were a feature of the light climate. Ratios of euphotic depth/mixing depth below 0.3 occurred in early 1992 and 1993.

Steep gradients in the physical and chemical environment were paralleled by variations in the phytoplankton. Algal biomass (as chlorophyll a) at Site 1, midstream opposite the water intake for the city of Rockhampton, ranged from 1.5 to 56.6 ug L-1. The vertical water column distribution of chlorophyll was variable with assemblages normally dominated by phytoflagellates and various species of cyanoprokaryotes. There was also higher relative abundance of chlorophyll a (reflecting increasing dominance of cyanoprokaryotes) in the latter half of the year and at the lower end of light availability. The specific vertical water column positioning with respect to light and temperature is shown for assemblages dominated by the genera Anabaena, Aphanizomenon and Cylindrospermopsis.

The most striking aspect of the phytoplankton was the long term dominance of cyanoprokaryotes and the species richness (particularly that of cyanoprokaryotes) when compared with the dearth of information to date on other tropical rivers. Seasonal successions were varied. Regularly occurring assemblages were cyanoprokaryotes (Oscillatoriales), euglenophytes or non-flagellated chlorophytes during flows followed by flagellated chlorophytes and then cyanoprokaryotes (Nostocales) during the dry season. Genera present indicated highly eutrophic conditions. Hierarchical agglomerative clustering of phytoplankton data and comparison with a principal components analysis of corresponding environmental data were used to demonstrate the linkage between steep environmental gradients and variation in the phytoplankton assemblage. The specific environmental conditions associated with the success of various species were also analysed and presented. Using the above information, a two-part model was proposed which predicts the most likely genera of phytoplankton with respect to multidimensional environmental gradients. This model covers a wide gamut of conditions varying from highly variable lotic to lentic environments.

As Cylindrospermopsis raciborskii was considered a most important species in relation to the quality of the water supply for Rockhampton, the physical, chemical and biotic conditions prior to and during a bloom of this species are described. A number of possible grazers of C. raciborskii were identified with a view to future biomanipulation. One of these, the large ciliate, Paramecium cf. caudatum was found to be an effective grazer of toxic straight C. raciborskii in the laboratory.

This study is unique in that it analyses the impact of episodic events (eg. major flooding) on the subsequent phytoplankton in the lower Fitzroy River. The model relating phytoplankton to multidimensional environmental gradients provides great information for use in management, particularly in relation to the prediction of toxic algal blooms.

 Fishways designed for salmonids in temperate rivers have often been successful, but similar fishways provided for non-salmonid species in tropical and sub- tropical rivers have frequently failed. In 1970 a salmonid style fishway was built on a tidal barrage on the sub -tropical Fitzroy River, in Queensland, north-eastern Australia. Despite modifications to the design in 1987 assessment of the fishway in 1978 and 1992 demonstrated that it was ineffective; particularly as few barramundi (Lates calcarifer [Centropomidae]) were found at the top of the fishway. The inadequacy of the design appeared to be related to very high water velocities and turbulence within the fishway pools. Consequently, since construction of the tidal barrage many catadromous fish populations (species that live in freshwater but breed in saltwater) have declined in the freshwater reaches of the Fitzroy River. 

In 1994 the fishway was modified to a vertical -slot design. The study reported in this thesis is an assessment of the effectiveness of the new design from 1995 to 1997. In 38 paired samples taken at the top and bottom of the fishway, over 16 months, 29 fish species and over 23,000 fish were collected at a maximum rate of 3,400 per day. At the top of the fishway 15,471 individuals were collected and 7594 at the bottom. The migratory population consisted of 4 marine species, 9 diadtomous species and 16 potamodromous species. Common species using the fishway included blue -catfish (Arius graeffei [Ariidae]), bony herring (Nematalosa erebi [Clupeidae]), striped mullet (Mugil cephalus [Mugilidae]), barramundi, and long -finned eels (Anguilla reinhardtii [Anguillidae]). Shrimp  Macrobrachium australiense [Palaemonidae]), juvenile crabs (Varuna litterata [Grapsidae]) and long -finned elvers did not ascend the full length of the fishway and specific fishways for these species are recommended. Fish between 25 and 640 mm in length ascended the fishway, although the passage of smaller size classes of immature fish was restricted which may be important for the sustainability of these migratory populations. The bulk of the biomass (71% at the top and 66% at the bottom) was made up of the diadromous blue -catfish of which 81 % were immature. Furthermore, a number of other common fish species were represented mostly by juveniles, including striped mullet, bony herring and barramundi. 

This study is the first record of barramundi successfully migrating through an in situ fishway in that no significant difference was found between the size of fish at the top and bottom. A major finding was that 95% of the barramundi from the fishway were immature fish (200-640 mm long), but significantly larger barramundi (maximum length 980 mm) were captured by angling near the base of the fishway. Nevertheless, enlargement of vertical -slot width from 0.15 m to 0.45 m only encouraged a small number of larger fish (890 mm maximum length) to enter. Interestingly, very small barramundi (45-163 mm long) were also absent from the fishway, but these were found in a small tidal tributary below the barrage. Very young barramundi appear to inhabit specific off - channel habitat before migrating in the main river at a larger size. The implications of these results are that 150 mm slot widths are suitable for barramundi and that different life stages have different migratory requirements.   

<i>Abstract</i> .—Central Queensland in Australia already has a highly variable rainfall and streamflow pattern. River flows of the largest local river, the Fitzroy, are seasonal and ephemeral and, between 1976 and 2008, varied in magnitude from around 349,677 to 22,903,390 ML per annum. Predictions of local climate change effects suggest that rainfall and streamflows will become more variable with less frequent but larger flood events and extended, more severe drought periods. SUNTAG is a program that has recorded details of tagged and recaptured fish in Queensland since 1986. CAPREEF is a community-based program that has collected catch-and-effort data from recreational fishers across Central Queensland since 2005. The SUNTAG and CAPREEF programs act as a long-term central repository to collect recreational fish tagging and catch information. The goal of this paper was to examine two models predicting changes associated with rainfall and streamflow, the first examining changes in barramundi <i>Lates calcarifer </i> recruitment in a wetland system and the second predicting changes in recreational catch rate of sand whiting <i>Sillago ciliata </i> and red throat emperor <i>Lethrinus miniatus</i> . Catch rates of young barramundi recruiting to a wetland in the Fitzroy River delta between 1985 and 2008 varied between 0 and 37 fish/d. The median catch rates of fishing clubs also varied widely, being highest in years following wet season flooding.