Hyrum Reservoir , Utah, was studied for one year during an artificial destratification project. Previously Drury et al. (1975) had studied Hyrum Reservoir for one year of stratified and one year of destratified conditions. The redistribution of dissolved oxygen to the hypolimnion significantly changed conditions for chemical and biological activities in the lower depths of the reservoir. The Aphanizomenon bloom increased with each year of destratification. The reservoir was changed by destratification so as to be suitable habitat for trout on a year round basis. Aerobic condi tions prevented iron from being released from the sediment into the aqueous phase . In summary the water quality of Hyrum Reservoir was highly affected by algal blooms, the interaction of bottom sediments with overlying waters especially in conjunction with spring and fall overturn, and the impact of materials and water flow from the Little Bear River.

This thesis was undertaken in order to explore aspects of the impact of outdoor recreation on water quality. It begins with a discussion of the rationale for monitoring and controlling such environmental degradation. Following sections include an investigation of water quality characteristics particularly indicative of recreational impact, a discussion of the potential contributions of various recreation activities to water pollution, a literature survey, a guideline for planning and implementing a water quality surveillance program, and recommendations for further research. Material for the thesis came from library research and was augmented by the author's personal experience as a water quality research technician.

The development of a model capable of predicting the long term (seasonal) distribution of water quality constituents within Great Salt Lake was undertaken as a portion of the ongoing Great Salt Lake project at Utah State University. The overall goal of the project is the development of a modeling framework to assist the relevant decision making bodies in the comprehensive management of the Great Salt Lake system. Phase I of the project provided the overall structural framework for management of the Great Salt Lake system, identified data needs, and established priorities for the development of submodels for incorporation into the overall framework. Phase II of the project involves the process of developing submodels, and Phase III will be concerned with application of the framework of models to specific management problems. This study provides, as part of the second phase of the Great Salt Lake project, a model capable of predicting the long term distribution of quality constituents within the lake. This capability is a necessary component of the modeling framework since it will allow the investigation of the effects which alternative water quality management plans will have on the distribution of water quality constituents within the lake. The water quality model of the lake is based on the application of the advection-diffusion equation to the three-dimensional transport of a quality constituent. The modeling technique is formulated by discretizing the system as a network of nodes interconnected by channels in both the horizontal and vertical directions. This representation of the system allowed the horizontal transport to be treated mathematically as one-dimensional. The resulting modeling technique is applicable to any lake, estuary, or bay in which the concentration gradients must be described in all three coordinate directions. In applying the model to Great Salt Lake a two-layered vertical network was employed due t o the physical characteristics of the system. The model was further simplified by describing vertical transport by diffusion alone. Using observed total dissolved solids concentrations, a method was developed during the study for establishing the vertical diffusion coefficient as a function of depth. A unique feature of this water quality modeling technique is that it allows the seasonal distribution of a quality constituent to be studied without the necessity of developing a hydrodynamic model of the system . The advective transport is designed to be input to the model based on observed long term circulation patterns . In the case of Great Salt Lake, circulation patterns are not yet well known. However, approximate patterns h a ,, e been established from some observations to date , and those were used to provide preliminary tests of the validity and response characteristics of the model. These tests have demonstrated that the model will be a practical and useful tool for monitoring the distribution of quality constituents within the lake.

Recent theoretical and technological advances in ecosystem science have dramatically expanded the ways in which scientists can pursue and explore ecological questions. For my thesis research, I integrated the recent theoretical concept of organisms as ecosystem engineers with the relatively recent development of stable isotope tracer tests to ask the question: how does the invasive common carp affect stream ecosystem structure and function? To investigate the structuring role of carp, I measured autotroph seasonal distribution and abundance and macroinvertebrate seasonal abundance and diversity within two stream reaches in Spring Creek, Utah, USA; one with low carp biomass (LCB) and one with high carp biomass (HCB). I installed a series of carp exclosures in the HCB reach to examine the response of the stream to carp exclusion. To explore the effects of carp on stream nitrogen dynamics, I performed a three week, continuous injection of 15N as ammonium chloride. The macrophyte and macroinvertebrate community was severely depauperate in the HCB reach compared to the LCB reach. The observed rapid colonization of a relatively abundant and diverse macrophyte and macroinvertebrate community at the carp exclusion sites in the HCB reach not only indicates that carp engineering reduces the abundance and diversity of these communities, but also highlights the importance of the spatial distribution of engineered and non-engineered patches in dictating the temporal scale of re-colonization. Carp engineering had a simplifying effect on stream N dynamics that ultimately limited the uptake and retention capacity of the HCB reach. For example, macrophytes played a dominant role in the N dynamics of the LCB reach by directly assimilating NH4, retaining N rich FBOM, and by providing habitat necessary to support an abundant and relatively diverse macroinvertebrate community that facilitated greater trophic transfer of nitrogen. Conversely, carp reduction of macrophytes in the HCB reach resulted in an overall reduction in areal uptake rates of NH4, reduced trophic transfer of N, and significantly reduced N retention. These results clearly indicate that carp engineering reduces macrophyte and macroinvertebrate abundance and diversity in streams and that N dynamics are simplified in carp engineered patches.

Remote sensing has the potential to monitor spatial variation in water quality over large areas. While ocean colour work has developed analytical bio-optical water quality retrieval algorithms for medium spatial resolution platforms, remote sensing of lake water is often limited to high spatial resolution satellites such as Landsat, which have limited spectral resolution. This thesis presents the results of an investigation into satellite monitoring of lake water quality. The aim of this investigation was to ascertain the feasibility of estimating water quality and its spatial distribution using Landsat 7 ETM+ imagery combined with in situ data from Rotorua and Waikato lakes. For the comparatively deep Rotorua lakes, r² values of 0.91 (January 2002) and 0.83 (March 2002) were found between in situ chlorophyll (chl) a and the Band1/Band3 ratio. This technique proved useful for analysing the spatial distribution of phytoplankton, especially in lakes Rotoiti and Rotoehu. For the more bio-optically complex shallow lakes of the Waikato, a linear spectral unmixing (LSU) approach was investigated where the water surface reflectance spectrum is defined by the contribution from pure pixels or endmembers. The model estimates the percentage of the endmember within the pixel, which is then used in a final regression with in situ data to map water quality in all pixels. This approach was used to estimate the concentration of chl a (r² = 0.84). Total suspended solid (TSS) concentration was mapped using the traditional Band 3 regression with in situ data, which combined atmospherically corrected reflectance for both images into a single relationship (r² = 0.98). The time difference between in situ data collection and satellite data capture is a potential source of error. Other potential sources of error include sample location accuracy, the influence of dissolved organic matter, and masking of chl a signatures by high concentrations of TSS. The results from this investigation suggest that remote sensing of water quality provides meaningful and useful information with a range of applications and could provide information on temporal spatial variability in water quality.

Freshwater vertebrates were sampled in different waters of the Upper Parramatta River catchment to determine their patterns of distribution with respect to water quality. A total of 730 animals (831 captures)were caught between November 1997 and December 1998. Data was collected on three freshwater turtle species, and four fish species.The abundance of aquatic vertebrates was correlated with physiochemical water quality parameters. The large aquatic vertebrates studied did not correlate with the commonly used parameters for aquatic health. The assumption ANZEEC water quality parameters are the definitive determinant of aquatic health for vertebrates is, therefore, erroneous. / Master of Science (Hons)

Sewage pollution from humans, animal and domestic sources (land and agricultural run-off) are recognized as a major cause of deteriorating water quality along Australia's coastline. Management of water quality has primarily relied on the use of bacterial indicator methods. However the validity and source-specificity of these methods have been met with increasing reservations for several years now. A relatively recent methodology uses a different chemical biomarker approach using 'sterols', a group of compounds related to the common bio-membrane lipid cholesterol and its derivatives. Sterols can offer an additional diagnostic tool to distinguish and discriminate between sources of faecal contamination in marine, freshwater and estuarine environments in both sediments and the water column. This study investigates for the first time, the degradation of coprostanol and selected faecal sterols in 'natural' sediments from a highly mixed (marine and estuarine) sub-tropical environment following a simulated pollution event (primary effluent); the use of faecal sterols as an additional indicator for determining non-point source sewage discharges at popular anchorages in the Moreton Bay and Gold Coast Broadwater system; and the use of sterol ratios in the determination of the fate and transportation of nutrients from a Sewage Treatment Plant (STP) point-source outlet pipe during plant malfunction. The microcosm degradation experiment revealed that faecal and selected sterols are continually synthesised and degraded over time by auto- and hetero trophic organisms within the sediment matrix. Coprostanol was the only sterol to degrade continually, with only minor fluctuations over a time period of two months. Results from this degradation experiment further revealed a sharp decline of coprostanol within the first week. From this it could be concluded that, without any further addition, external inputs of coprostanol are reduced to background levels within this time period. Therefore, removal of coprostanol after six days was 94% and 73% in mud and sand, respectively. The removal of coprostanol was much higher in mud than sand, reflecting a higher level of microbial activity in muddy sediments for assimilation of sterols. The field study undertaken at popular anchorages in Moreton Bay and the Gold Coast Broadwater revealed extremely low levels of sterols and bacterial indicators over both a spatial and temporal scale consistent with a shallow, oligotrophic, highly dynamic sand dominated system. Even though sterols analysed were found at extremely low levels (mostly in the nano-gram range), they were found to be highly correlated and were successful in identifying an unexpected once off pollution event from a point source at Moreton Bay Island. Other than this one incident, both sterol and bacterial levels were consistently low even when anchorages were at full capacity. Thus, sewage from recreational vessels was found to have very little, if any, effect on the water quality at anchorages in Moreton Bay and Gold Coast Broadwater. The point-source study conducted during a local sewage treatment plant malfunction revealed that even though absolute concentrations of sterols did not change during this event, the distribution of sterols within the samples changed, hence changing the sterol ratios. Further, nutrients (mainly nitrogen) can be transported several kilometres by currents, flocculate out of the water column and settle out into the sediment in areas with low tidal and hydrological flushing. There, the nutrients can cause in situ production of sterols in sediments changing sterol ratios. Overall, this study revealed that analyses of sterol biomarkers have the potential to indicate nutrient inputs (such as nitrogen) as well as sewage, post-hoc pollution events at extremely low levels/high dilutions in coastal sediments.

This thesis investigates the distribution and significance of stream turbidity in Victoria; specifically exploring the factors that may have influenced the pattern of regional variation in turbidity, and factors that give it significance in the regional, social, cultural and environmental context. The limits to water availability are set, not only by the quantity of water in storages or streams but, more fundamentally, by acceptable levels of water quality and catchment health. To make effective judgements of water availability managers of water resources need to know the significance of measured natural resource condition in the regional context. Stream turbidity can be considered by the agricultural community as a sign of soil erosion and a loss of agricultural potential, while from the ecological perspective it can be considered a sign of deteriorating river health. Fundamentally, levels of turbidity are closely bound with land use practice and, in the Australian context, turbidity can be considered a measure of the consequences of land management practices on soil erosion and run-off. Measured levels of turbidity in Victoria should be interpreted within the context of a unique history and geography. The spread of European colonisation and the introduction of massive land use change to the Victorian landscape have meant that over most of Victoria current levels of turbidity reflect the effects of over a hundred and fifty years of large scale intervention with its controlling factors. In Victoria current levels of turbidity are interpreted in a cultural context far different from that of early colonists or even of a few decades ago. The concept of Ecologically Sustainable Development which has dominated natural resource management in recent times brings new responsibilities to resource managers. Ecologically sustainable management means that resources must be considered in a more inclusive spatial and temporal context. In the early stage of Victoria's history sustainable management of water meant having enough water left from winter rains to supplement summer supply. However, in recent years, it has begun to have more complex associations; sustainable water use is now, almost universally considered to include maintenance of the environmental health of waterways, and by implication, the environmental health of the whole catchment. In this context, stream turbidity can be considered a useful indicator of catchment health, in particular, because levels of turbidity bear a direct physical relationship to catchment processes. New tools are needed to explore the relationship between land use and water quality at the regional scale. The results of this current research include a regional statistical model of stream turbidity, which is conceptually designed to offer useful predictions of stream turbidity and underpin sustainable resource management. The statistical model was used as input to the development of a unique map display using Geographic Information Systems (GIS). The GIS is used to display the distribution of model predictions over a large region of south-eastern Australia. The practical advantage of this modelling approach is that it provides managers with the ability to identify locations in Victoria where measured water quality differs significantly from modelled water quality and flag them for further investigation. The major project outputs are a map of Victorian Water Quality Monitoring Network (VWQMN) catchments showing catchments in Victoria where measured turbidity differs from model predictions and a raster representation of the state of Victoria in which cell values indicate predicted stream turbidity. Important to this project was the novel use of GIS technology to process large national and regional scale digital data sets using tools developed for catchment scale hydrological models.

In this thesis, a combination of laboratory experimentation under well defined conditions coupled with a kinetic modelling approach is used to verify the existence and respective kinetic rates of previously unconfirmed or postulated mechanisms that drive and limit dark Fenton (Fe(II)/H2O2) - mediated As(III) oxidation at pH 3 and 8 and dark Cu(II) - H2O2 - mediated As(III) oxidation at pH 8. Dark Fenton - mediated oxidation of As(III) at pH 3 is first examined and the effects of the variation in the concentration of reactants (As(III), Fe(II) and H2O2), oxygen, phosphate and organics (2 - propanol, formate, and citrate) are reported and analysed. The kinetic models developed for these systems show high applicability to full scale water treatment application and key mechanistic findings include the significance of the cycling of Fe(II) / Fe(III) via HO2 ???/O2 ??????, the effects of As(IV) termination reactions in the absence of oxygen and the retarding effects of phosphate due to the postulated formation of a Fe(III) - phosphate complex (at a derived rate constant of 2.2 x 106 M-1s-1, that also appears to have negligible kinetic activity in terms of reduction to Fe(II) by HO2 ???/O2 ??????). The work also demonstrates the significance of the free radical by products of formate and citrate oxidation by ???OH (HCOO???/CO2 ?????? and 3HGA???2???). The examination of the dark Cu(II) - H2O2 - mediated oxidation of As(III) at pH 8 with variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate and organics (2 - propanol, formate and citrate) demonstrated for the first time the high applicability of this system to the pre - oxidation of As(III) in water treatment and mechanistically that ???OH and CO3 ?????? are the dominant As(III) oxidants in this system. The As(III) oxidant CO3 ??????, is suggested to be generated by the interaction of ???OH and O2 ?????? with the carbonate matrix, at the respective rate constants of 4.9 x 107 M-1s-1 and 5.5 x 106 M-1s-1. Examination of the dark Fenton - mediated oxidation of As(III) at pH 8 and the effects of variation in the concentration of reactants (As(III), Fe(II) and H2O2), carbonate, organics (2 - propanol, formate and citrate) and Cu(II) demonstrates the varied potential mechanistic pathways in relation to the generation of As(III) oxidants from the Fenton reaction, Fe(II) + H2O2 such as Fe(IV) and CO3 ?????? and the previously dismissed ???OH, due to the presence of Fe(II) - citrate complexes. This work also demonstrates and models the enhancement of As(III) oxidation in the presence of an additional transitional metal ion, Cu(II).

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