A biological monitoring tool to assess water quality using bivalve gape behavior was developed and demonstrated. The purpose of this work was to develop methodologies for screening water quality appropriate to the goals of the watershed paradigm. A model of bivalve gape behavior based on prediction of behavior using autoregressive techniques was the foundation of the bivalve biomonitoring system. Current technology was used in developing the system to provide bivalve gape state data in a continuous real-time manner. A laboratory version of the system, including data collection and analysis hardware and software, was developed for use as a toxicological assay for determination of effective concentrations of toxicant(s) or other types of stress on bivalve gape behavior. Corbicula fluminea was monitored and challenged with copper, zinc, and chlorpyrifos using the system. Effective concentrations of 176±23µg/L copper, 768±412µg/L zinc, and 68µg/L chlorpyrifos were observed using a natural water with high dissolved organic carbon concentrations. A rugged field version of the bivalve biomonitoring system was developed and deployed in two locations. The field systems were fitted with a photovoltaic array, a single board computer, and a CDPD telemetry modem for robust remote operation. Data were telemetered at a time relevant rate of once every ten minutes. One unit was deployed in Lake Lewisville, Denton County, TX in February 2000. Data were telemetered and archived at a 92% success rate. Bivalve gape data demonstrated significant behavioral deviations on average 5 times per month. A second unit was deployed in Pecan Creek, Denton, TX in June 2001. Data from this site were telemetered and archived at a 96% success rate. Over the months of June-August 2001, 16 significant behavioral deviations were observed, 63% of which were correlated with changes in physical/chemical parameters. This work demonstrated the relative sensitivity of bivalve gape as a toxicological endpoint and the feasibility of its use in a continuous, real-time, bivalve biomonitoring system. Technical aspects of collecting, telemetering, and analyzing this type of data in a time-relevant manner were developed resulting in a system appropriate for use as a means of data collection within the watershed paradigm.

The primary objective of this study was to develop and evaluate a system capable of rapid, continuous collection of water quality and locational data on Lake Texoma. Secondary objectives included developing monthly distribution maps for chlorophyll-a, turbidity, and specific conductivity in Lake Texoma and investigating the spatial and temporal relationships between these common water quality indicators. A modified YSI multiprobe was used to develop a system capable of surveying the lake within 4 days with samples at 330 to 400 meter intervals. Data generated with this system compared favorably with previous studies of Lake Texoma. Two sets of raster format maps were developed for the monthly distributions of chlorophyll-a, turbidity, and specific conductivity across the lake. Spatial and temporal relationships generally took the form of decreasing gradients running from the lake arms towards the Main Lake Zone in the case of chlorophyll-a and turbidity. Or, in the case of specific conductivity, a decreasing gradient from the Red River arm to the Washita River arm. All three water quality indicators were strongly influenced by river discharge levels.

D.Ing. / Measuring the efficiency of water utilities has been a constant challenge to various stakeholders in the water sector. There are several factors that influence the efficiency of utilities. The following study examines the different factors and establishes a model to quantify the efficiency of water utilities using limited number of variables. It utilises Fuzzy Logic to develop the measurement model. The developed method can also be used to configure a new water utility for efficiency. In addition, the research highlights some possible imperfections in the water policies that can result in an inherent inefficiency of a water utility. The developed model can assist in setting ceiling levels for utility's water assets and labour, to ensure efficiency. The model is generic and can be applied to any country or community, and can be used to configure water utilities for the poor. The Model utilised "Matlab Fuzzy Tool Box student version 2009a" software as a tool to develop the Fuzzy Inference Engine for Utility Efficiency. The study is a contribution to the domain of knowledge of water engineering science.

M.Sc. / Water resources in South Africa are scarce and need to be protected and managed in a sustainable way for future generations. Food supply is a great priority worldwide and the pressure to produce enough food has resulted in the expansion of irrigation and the steadily increasing use of fertilizers and pesticides to achieve higher yields. Rivers are impacted by agriculture through increased suspended sediment loads (which affects primary production, habitat reduction and introduction of absorbed pollutants), elevated nutrient inputs (which may increase the abundances of algae and aquatic plants), salinization and pesticide runoff (which eliminates species intolerant to these conditions and therefore impacts on the normal production of the river system). Aquatic biota plays an integral part in the functioning of aquatic ecosystems. Biological monitoring is used to assess ecosystem health and integrity. Biological communities reflect the overall integrity of the river ecosystem by integrating various stressors and therefore provide a broad measure of their synergistic effects. The research area falls within the Lower Vaal Water Management Area (WMA), which lies in the North-West and Northern Cape Provinces. The lower Vaal River and the Harts River (one of the tributaries of the Vaal) are the river systems under investigation in this study. Farming activities ranges from extensive livestock production and rain fed cultivation to intensive irrigation enterprises at Vaalharts (such as maize, cotton and groundnuts). The Vaalharts is the largest irrigation scheme in South Africa. Salinity is of concern in the lower reaches of the Harts- and Vaal Rivers, due to saline leachate from the Vaalharts irrigation scheme. Agricultural inputs are known to affect aquatic communities and chemicals (e.g. pesticides, herbicides, fertilizers) are extensively used in the Vaalharts irrigation scheme. At present there are no data on the effect of these chemicals on the aquatic biota of the lower Harts- and Vaal Rivers. The aims of this study were to assess the diatom- and macroinvertebrate community structures, ecosystem integrity and macroinvertebrate feeding traits (functional feeding groups – FFGs) in relation to land use.

Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2010 / Freshwater scarcity and river pollution has become a serious challenge for governments and scientists. Worldwide, governments have a responsibility to provide their populations with enough clean water for their domestic needs. Scientists will have an enormous task to find a way to purify polluted water, because of its vital role in human lives and an increasing demand for water consumption due to population growth. Although the water from the Bottelary River is used on a daily basis for farming activities, its pollution level as well as spatial distribution of effluents in the catchment is unknown. In the present study, I took monthly water samples from six sampling points for laboratory analysis. The laboratory determined concentration levels of phosphorous, chloride, nitrate, and nitrate nitrogen (N03N), as well as the chemical oxygen demand (COD) and suspended solids from the samples. On the same occasion's pH, dissolved oxygen, electrical conductivity and temperature were measured in-situ using a multi-parameter reader. The results were then compared with the South African Water Quality Guidelines for Aquatic Ecosystems and for irrigation (DWAF, 1996a, 1996c). The non-point pollution source (NPS) model was used to generate predictions of the pollution level from the land-uses and use the data obtained from the field to validate the model predictions. Finally, I performed a two-factorial A One-way Analysis of Variance (ANOVA) without replication to assess the spatial and temporal variation of the measured variables along the river. The findings of the study have shown that the concentration levels of some compounds are below the Target Water Quality Range (TWQR) set by the Department of Water Affairs and Forestry (DWAF, 1996a, 1996b, 1996c) while, the concentrations of chloride, total nitrogen and water quality variables such as electrical conductivity, suspended solids, are higher than the TWQR (DWAF, 1996a, 1996b, 1996c). Based on the above findings water of the Bottelary River can have negative effects on the environment and human lives because of the concentration level of these compounds. It was therefore recommended that, environmentally friendly measures and practices must be undertaken in order to decrease the pollution and avoid further pollution of the river.

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Freshwater of acceptable quality is crucial for certain needs and uses such as recreational, domestic and industrial activities (Bartram and Balance, 1996). Water contamination and excessive use and abuse of the fresh water environment, threaten development as well as a variety of other life aspects and make water assessment necessary for safe drinking water delivery. It has been proven that water of good quality is important to sustain development (Karolina et al., 2011). South African freshwater resources such as lakes, rivers and groundwater, undergo intense stress owing to a rapidly expanding population, a growing economy, severe pollution from various industries, a possible effect of global warming and an increase in droughts (Oberholster et al., 2008). A study done by Boyd (2010), further confirmed the decline in water quality of these resources due to excessive contamination caused by urban development, human activities, industrialisation, forest establishment, agriculture and mining operations. For this project, the analysis of physical, chemical and biological parameters of the water from Lake Nsezi was used to assess the water quality of the lake. Results from the analysis were compared to Target Water Quality Range (TWQR) of the Water Quality Guidelines for the Aquatic Environment (WQG/AE) and for Domestic Use (WQG/DU). A further comparison was done between data from the current study and available historical water quality data of Lake Nsezi. From the results for this project and historical data, it was evident that parameters such as total dissolved solids (TDS) and chloride, metals such as aluminium, cadmium, copper, lead and manganese, and total coliform counts were above the TWQR for the WQG/AE and WQG/DU at most of the sampling sites. / Environmental Sciences / M. Sc. (Environmental Science)

No description available.

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Overabundant nitrate in Iowa’s surface water threatens stream health, drinking water safety, and significantly contributes to hypoxic zones in the Gulf of Mexico. Researchers have quantified surface water nitrate loads historically with grab samples and, more recently, in-situ sensors. In-situ sensor networks capture changes in nitrate concentration over small time scales, providing high temporal resolution data to accurately calculate nitrate loading. However, because advanced sensors are expensive, spatial resolution is often compromised when sensors are deployed on large rivers. To collect high spatial resolution nitrate samples that complement the high temporal resolution data from in-situ sensors, we first used traditional grab samples on small, non-navigable streams in the Clear Creek and the English River watersheds. Dense grab samples across watersheds provide higher resolution data, but not at the spatial resolution achievable on navigable streams with newly developed, boat-deployed sensor technology. We constructed a boat-deployed sensor system that automatically measured nitrate concentrations, temperature, dissolved oxygen, conductivity, and pH as we navigated a boat on a given waterbody. We used the system on the Iowa and Cedar Rivers to capture spatial and temporal changes never previously observed in Iowa. Our data suggest nitrate concentrations and yields were highest in low-relief landforms dominated by row crop agriculture. Nitrate concentrations were lower in higher-relief landforms with less row crop production. We also measured water in Storm Lake, IA with the boat-deployed system. We measured little heterogeneity of nitrate concentrations in the lake, but observed significant nitrate reduction in a large wetland just upstream. The system captured fine scale spatial dynamics of nitrate reduction in the wetland and low nitrate concentrations throughout Storm Lake. Our newly developed sensor platform captured high resolution water quality data, complementing the high temporal resolution data collected with in-situ sensors. High spatial resolution data in this and similar studies provide powerful insights for decision makers to target problematic areas, reduce nitrate, and improve water quality.