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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Comparison of Wetland Assessment Methods

Green, Kerstin 01 January 2011 (has links)
After many decades of being considered useless and often destroyed wetlands have become valued for the many functions they provide. To make informed wetland management decisions biologists have to develop practical, rapid, and inexpensive ways to assess biological conditions and functions. Ideally these assessment methods have to measure more than one attribute of the wetland to represent the overall condition of the biological community. For this project I conducted field assessments at mitigation sites in Pembroke Pines, Florida, to see how the newest method used in the State of Florida, the Uniform Mitigation Assessment Method (UMAM), compared to the older Wetland Rapid Assessment Procedure (WRAP), and a Wildlife Survey (WS). The assessments determined at what level the mitigation sites of this study functioned, and were than repeated over a thirteen month period to account for seasonal fluctuations. For each assessment method a worksheet was completed, which along with available background information for the sites, was used to determine the value, and function provided by the wetlands. The three methods were then compared using eleven evaluation criteria I developed. Based on my results UMAM was the best assessment method tested saving the most acreage while integrating risk factors and time lag.
102

Seasonal exposure in the form of precipitation and its effect on water quality for the Roodeplaat dam drainage basin : 2000-2009

Lomberg, Nicole Janet 11 February 2014 (has links)
M.Sc. (Environmental Management) / The main purpose of this study is to determine whether trends in rainfall patterns correlate to trends in water quality constituents for the Roodeplaat Dam Drainage Basin, thereby increasing the ‘dilution capacity’ potential of the aforementioned water system. The Roodeplaat Dam (reservoir) is a hypertrophic impoundment located approximately 20 kilometres north-east of Pretoria. The dam was originally designed for irrigational purposes and later became an important recreational site. In recent years it serves as an important source for Magalies Water, which represents a state-owned water board that currently supplies potable water to a large area north of Pretoria. The Roodeplaat Dam catchment consists of three contributing rivers to the inflow of the impoundment, namely: The Pienaars River (located in the centre of the catchment), the Edendale Spruit (east of the catchment) and the Moreleta/Hartebees Spruit (west of the catchment). There are also two Water Care Works (Zeekoegat and Baviaanspoort) within the catchment, which supplement additional inputs of treated effluent discharges to the reservoir. Temporal changes in selected physical, chemical and microbial constituents were analysed at established sampling points along each river, including a sample site located at the dam wall outlet. Such changes in water quality, in conjunction with rainfall patterns exhibited in the study area were analysed to determine whether an association exists between the two variables, and more specifically how rainfall impacts on water quality within the catchment which has a direct effect on the quality of the Roodeplaat Dam. Data for rainfall and water quality were analysed over a 10 year period, from January 1999 to December 2009. Water quality sampling results were obtained from the Department of Water Affairs. Rainfall data for the same time period in question was obtained from the South African Weather Service. Results for both variables were projected graphically and collated to determine whether rainfall trends have an impact on concentrations of water quality constituents. Constituent concentrations were also compared at each sample site. To quantitatively justify graphical results, the author preformed Pearson’s and Spearman’s correlation analysis to establish whether rainfall and water quality concentrations displayed significant associations. Results from graphical presentations and quantitative analyses identified that a correlation does exist between rainfall and water quality constituents, whereby an increase in rainfall tends to result in a decrease of water quality constituent concentrations. Microbial constituents contrasted to physical and chemical results, and displayed a strong positive correlation to rainfall. Rainfall therefore increases the ‘dilution capacity’ potential of the catchment, whereby the water system increases in its ability to receive and remove pollutants disposed in them by human induced land-use activities. It was also found from the study that the strength and association between rainfall and water quality constituents is affected by external, anthropogenic variables which also exert an influence on the quality of water present in the Roodeplaat Catchment Area. This includes additional inputs from the Baviaanspoort, which is located along the Pienaars River. Results from the sample site located on this river displayed no relationship for many of the water quality constituents tested. It has also been highlighted from the study how the landscape has been severely altered by the rapid rate of human induced land use activities in the past decade. Further investigations need to incorporate the influences of natural phenomena, such as rainfall, together with influences exerted from anthropogenic activities. This will provide clearer information on the interdependent factors at play which compromise the dilution capacity potential of the Roodeplaat Catchment Area and subsequently the poor water quality status exhibited at the impoundment. Once such externalities are accounted for, it is recommended that a suitable management plan be conducted for the Roodeplaat Catchment Area that is based on scientific grounding and proactively mitigates the impacts exuded by land-use activities, thereby improving the status of the Roodeplaat impoundment.
103

Optimizing land acquisition-conversion projects for water quality protection and enhancement using biological integrity endpoints

Wente, Stephen P. January 1996 (has links)
Biological monitoring and land use data analysis were performed for a small (79,800 acre) watershed in west-central Indiana. A model was developed between Hilsenhoff biotic index and percentage of water (volume) draining through forestland at each sample site (R2.92, P < .002). This water volume model was found to explain more of the variation in biological integrity than USEPA and Ohio EPA habitat assessment methods, as well as, a land use model based upon percentage watershed surface area. Based on this water volume model, maps were created depicting regions within the watershed that had the greatest potential to damage water quality. Land acquisition/conversion projects based upon these maps should improve biological integrity/water quality more efficiently (requiring less land acquisition/conversion, and therefore lowering project costs, while increasing water quality benefits). / Department of Biology
104

A study of the impact of anthropogenic activities in the Crocodile River, Mpumalanga

Soko, Mthobisi Innocent 25 November 2014 (has links)
In South Africa water is recognized as a crucial element in the battle against poverty, the cornerstone of prosperity, and a limiting factor to growth. The National Water Act 36 of 1998 recognizes that basic human and environmental needs should be met and that the use of water in all aspects must be sustainable. The Crocodile River (East) is situated in the north east of the Republic of South Africa and it is recognized as a stressed catchment in South Africa. The main impacts are domestic, industrial, agricultural, mining and afforestation activities. These activities pollute the river by discharging effluent as well as seepage from areas that support mining and intensive agriculture in to the river. The river catchment has been a center of research studies for many scientists either focusing on water quality or biological indicators separately. The aim of study was to determine the present ecological condition and the health of the Crocodile River. The objectives were to determine water quality status, identify possible sources of pollution and assess the spatial and temporal trends in ecological state. Fourteen monitoring sites were selected from the Crocodile River and its tributaries. The macro-invertebrates data were collected using the SASS 5 protocol and fish were collected using an electroshocker- catch and release method during high and low flow conditions of the year 2013. Water quality data was obtained by sampling using a polyethylene bottle from different sites within the Crocodile River and its tributaries from September 2012 until August 2013. The samples were analyzed by Mpumamanzi laboratory in Nelspruit and Waterlab in Pretoria. Additional water quality data was obtained from the Department of Water Affairs. Multivariate statistical methods were used to analyze all the data obtained. The multivariate statistical methods indicated that fish and macro-invertebrates species abundance, richness and evenness increase with the river flow distance downstream. Water temperature was one of the leading environmental variables for the structuring of fish and macro-invertebrates assemblage in the Crocodile River and its tributaries. A group formation of site during high and low flow condition by the Bray Curtis similarity and NMDS ordination indicated that many sites share similar macro-invertebrates or fish species. The one way ANOVA analysis indicated that there was no significance difference between macro-invertebrates richness and abundance during both flow conditions but there was a significance difference in fish richness and abundance between the two flow conditions. The PCA indicated that sodium has the highest physico-chemical impact amongst the physico-chemical parameters in the bi-plot followed by ammonium and nitrate. A correlation of physico-chemical parameters such as chlorine, total dissolved solid, electrical conductivity, sulphate and pH was observed. The levels of total dissolved solids and electrical conductivity were found to increase longitudinally as the river flows downstream. The dominance of single species within the macro-invertebrates and fish communities was an indication of imbalance of the communities within the sites. The presence of the macro-invertebrate family Beatidae and the fish species Chiloglanis pretoriae at sites CR3 and CR4 indicates a good water quality in the upper reaches during low flow condition as these species are sensitive to changes in water quality, while the presence of the macro-invertebrate family Pleidea and fish species Barbus viviparus at sites CR10 and KR1 during low flow condition indicated possible water pollution as these species tolerate changes in water quality and this was linked to the discharge of effluent from industrial, abandoned mines and run-offs from agricultural activities in the downstream reaches of the river. The low flow condition was dominated by sensitive species especially in the upper reaches than during high flow condition. The macro-invertebrates assessment index indicated that during low flow condition the Crocodile River was mostly at ecological class B (largely natural with few modification) above the Kwena dam, but from downstream of the dam the ecological category was in C class (moderately modified), while its tributaries are in ecological category B (largely natural with few modification). The fish response assessment index indicated that the ecological category for fish was mostly at C class (moderately modified) in the Crocodile River. The changes in macro-invertebrates communities and fish in the Crocodile River were believed to be associated with change of water quality and habitat modification due to flow modification. Agricultural activities in the upper reaches and a combination of industrial and mining activities in the middle and lower reaches of the Crocodile River were believed to be the sources of pollution that results in the change of water quality, fish and macro-invertebrates assemblage in the Crocodile River. Investing in the health of the Crocodile River is important for many Mbombela citizens and river dwellers as they rely on the functioning of the river for survival. / Environmental Sciences / M. Sc. (Environmental Science)
105

Monitoring of heavy metals in the Bottelary River using Typha capensis and Phragmites australis.

Ma, Ying January 2005 (has links)
The aim of this study was to use plants to determine the degree of heavy metal contamination in water and sediments in order to effectively monitor and provide possible recommendation to improve the water quality in the aquatic ecosystem of the Bottelary River.
106

Characterisation of the health, habitat use and movement of adult lowveld largescale yellowfish (Labeobarbus marequensis Smith, 1841) and other fishes in the Crocodile River, Kruger National Park

11 September 2013 (has links)
M.Sc. (Aquatic Health) / Yellowfish and specifically Labeobarbus marequensis are a charismatic species targeted by anglers throughout South Africa. Their population are limited to the north-western parts of the country including the lower reaches of the Crocodile River that flows through the Kruger National Park (KNP). Despite conservation efforts the Crocodile River in the KNP is still highly impacted. The effect of these impacts on the ecosystem is largely unknown. The main aim of the study was to determine the influence of changing water quantity and quality in the Crocodile River on adult L. marequensis. This was achieved by evaluating altered flows (discharge) on the behaviour of adult L. marequensis in the Crocodile River using biotelemetry over a two year period. The influence of altered water quality was assessed using metal bioaccumulation as an indicator of metal exposure in L. marequensis, Clarias gariepinus and Hydrocynus vittatus in the Crocodile and Sabie Rivers during a high and low flow season. Biotelemetry was used on 16 L. marequensis and 12 H. vittatus to determine the habitat use and movement responses of the species. Fish were tagged with Advanced Telemetry Systems (ATS) and Wireless Wildlife (WW) tags and tracked remotely and manually. Home ranges were determined using Arc GIS ®, Habitat uses were analyzed using Windows Excel (© 2011, Microsoft inc.). Environment variables recorded were scored as primary and secondary and then combined with a weighting variable 2:1 ratio (primary variable: secondary variable). A mixed-model analysis of variance (ANOVA) approach with a random co-efficients model and Akaike’s information criteria (AIC) were used to test for significance. Analyses were conducted using SAS version 9 (SAS institute, Cary, NC)...
107

A study of the impact of anthropogenic activities in the Crocodile River, Mpumalanga

Soko, Mthobisi Innocent 25 November 2014 (has links)
In South Africa water is recognized as a crucial element in the battle against poverty, the cornerstone of prosperity, and a limiting factor to growth. The National Water Act 36 of 1998 recognizes that basic human and environmental needs should be met and that the use of water in all aspects must be sustainable. The Crocodile River (East) is situated in the north east of the Republic of South Africa and it is recognized as a stressed catchment in South Africa. The main impacts are domestic, industrial, agricultural, mining and afforestation activities. These activities pollute the river by discharging effluent as well as seepage from areas that support mining and intensive agriculture in to the river. The river catchment has been a center of research studies for many scientists either focusing on water quality or biological indicators separately. The aim of study was to determine the present ecological condition and the health of the Crocodile River. The objectives were to determine water quality status, identify possible sources of pollution and assess the spatial and temporal trends in ecological state. Fourteen monitoring sites were selected from the Crocodile River and its tributaries. The macro-invertebrates data were collected using the SASS 5 protocol and fish were collected using an electroshocker- catch and release method during high and low flow conditions of the year 2013. Water quality data was obtained by sampling using a polyethylene bottle from different sites within the Crocodile River and its tributaries from September 2012 until August 2013. The samples were analyzed by Mpumamanzi laboratory in Nelspruit and Waterlab in Pretoria. Additional water quality data was obtained from the Department of Water Affairs. Multivariate statistical methods were used to analyze all the data obtained. The multivariate statistical methods indicated that fish and macro-invertebrates species abundance, richness and evenness increase with the river flow distance downstream. Water temperature was one of the leading environmental variables for the structuring of fish and macro-invertebrates assemblage in the Crocodile River and its tributaries. A group formation of site during high and low flow condition by the Bray Curtis similarity and NMDS ordination indicated that many sites share similar macro-invertebrates or fish species. The one way ANOVA analysis indicated that there was no significance difference between macro-invertebrates richness and abundance during both flow conditions but there was a significance difference in fish richness and abundance between the two flow conditions. The PCA indicated that sodium has the highest physico-chemical impact amongst the physico-chemical parameters in the bi-plot followed by ammonium and nitrate. A correlation of physico-chemical parameters such as chlorine, total dissolved solid, electrical conductivity, sulphate and pH was observed. The levels of total dissolved solids and electrical conductivity were found to increase longitudinally as the river flows downstream. The dominance of single species within the macro-invertebrates and fish communities was an indication of imbalance of the communities within the sites. The presence of the macro-invertebrate family Beatidae and the fish species Chiloglanis pretoriae at sites CR3 and CR4 indicates a good water quality in the upper reaches during low flow condition as these species are sensitive to changes in water quality, while the presence of the macro-invertebrate family Pleidea and fish species Barbus viviparus at sites CR10 and KR1 during low flow condition indicated possible water pollution as these species tolerate changes in water quality and this was linked to the discharge of effluent from industrial, abandoned mines and run-offs from agricultural activities in the downstream reaches of the river. The low flow condition was dominated by sensitive species especially in the upper reaches than during high flow condition. The macro-invertebrates assessment index indicated that during low flow condition the Crocodile River was mostly at ecological class B (largely natural with few modification) above the Kwena dam, but from downstream of the dam the ecological category was in C class (moderately modified), while its tributaries are in ecological category B (largely natural with few modification). The fish response assessment index indicated that the ecological category for fish was mostly at C class (moderately modified) in the Crocodile River. The changes in macro-invertebrates communities and fish in the Crocodile River were believed to be associated with change of water quality and habitat modification due to flow modification. Agricultural activities in the upper reaches and a combination of industrial and mining activities in the middle and lower reaches of the Crocodile River were believed to be the sources of pollution that results in the change of water quality, fish and macro-invertebrates assemblage in the Crocodile River. Investing in the health of the Crocodile River is important for many Mbombela citizens and river dwellers as they rely on the functioning of the river for survival. / Environmental Sciences / M. Sc. (Environmental Science)
108

Monitoring of heavy metals in the Bottelary River using Typha capensis and Phragmites australis.

Ma, Ying January 2005 (has links)
The aim of this study was to use plants to determine the degree of heavy metal contamination in water and sediments in order to effectively monitor and provide possible recommendation to improve the water quality in the aquatic ecosystem of the Bottelary River.
109

Use of bioindicators and biomarkers to assess aquatic environmental contamination in selected urban wetlands in Uganda

Naigaga, Irene January 2013 (has links)
Pollution of aquatic resources in Uganda is on the increase and the trends are expected to increase with increase in population size and urbanisation. Assessment and mitigation of the environmental impacts on water quality and biodiversity have now become necessary. The aim of the study was to integrate invertebrate and fish as bioindicators and fish histopathology as a biomarker in the assessment of water quality deterioration in urban wetlands in Uganda. The integration harnesses the advantages and counteracts the shortcomings of each method and thus builds a more robust diagnostic tool that gives a better view of the impacts to the entire ecosystem. Four endpoints which included, physicochemical variables, benthic macroinvertebrate bioindicators, fish bioindicators and fish histopathology biomarkers were compared between varied effluent-impacted wetlands (Murchison Bay in Kampala, and Kirinya, Masese and Winday Bay in Jinja) and a non-impacted reference wetland (Lwanika in Mayuge). Results from the effluent-impacted sites differed from the less impacted reference site. The two sampling locations at Murchison Bay (inshore and offshore) and one sampling location at Kirinya (inshore), that were highly impacted with urban effluent, showed elevated nutrient levels, low pH, dissolved oxygen and secchi depth readings. This corresponded with low invertebrate taxa and fish species diversity and richness; and severe histopathological responses in liver, gonads and gills of O. niloticus. Sensitive taxa such as ephemeroptera and trichoptera were completely absent while pollution tolerant taxa Chironomus sp, Corbicula and Oligochaeta were present. Also notable was the absence of many native haplochromines and presence of mainly Brycinus sadleri, Oreochromis niloticus and leucostictus. The organs manifested high prevalence of severe inflammatory and regressive changes and higher organ indices that fell within the pathological category. These sites were consistently classified as highly polluted under the four endpoints. The reference site was classified as least polluted while Masese and Winday Bay were moderately polluted. Results suggested that the approach of using invertebrate and fish as bioindicators and the fish histopathology as a biomarker, in relation to water quality physicochemical variables was a useful tool in highlighting the spatial differences in environmental quality.
110

Application of macroinvertebrate based biomonitoring approaches to assess anthropogenic impacts in the Swartkops River, South Africa

Odume, Oghenekaro Nelson January 2011 (has links)
A growing human population accompanied by urbanisation and industrialisation have led to over exploitation and pollution of freshwater resources and have consequently impacted on aquatic ecosystem health. The Swartkops River in the Eastern Cape of South Africa is no exception. It drains a heavily industrialised catchment which has led to deterioration of its water quality due to pollution. Integrated water resources management (IWRM) requires the concurrent sustainable use of water resources and the protection of aquatic ecosystem health. Macroinvertebrates are well known for their ability to reflect the health of the environment in which they live, thus they were used to assess anthropogenic impacts in the Swartkops River for this study. Macroinvertebrate based biomonitoring approaches, including the South African Scoring System version 5 (SASS5); a multimetric approach involving 19 metrics; Chironomidae community assessments and screening of morphological deformities in Chironomidae larvae, were applied at four selected sampling sites to assess environmental water quality in the Swartkops River. Macroinvertebrates were sampled us ing the SASS5 protocols. Chironomidae were mounted and identified as far as practically possible using available keys. Mentum, ligula, mandible, paraligula and antenna in Chironomidae larvae were screened for deformities. Physical and chemical water quality variables were measured at each of the selected sampling sites. All data were subjected to relevant statistical analyses. Of the four sites sampled during the study period, results revealed that water quality at site 1 was the least impacted with highest SASS5 scores, average score per taxa (ASPT) values, richness, diversity, equitability and Ephemeroptera –Plecoptera-Trichoptera (EPT) richness, as well as least incidences of chironomid deformities. Water quality at site 2 was considered the next least impacted with higher SASS5 scores, A SPT values, richness, diversity and equitability, and lower incidences of deformities compared to sites 3 and 4. SASS5 scores and ASPT values revealed that both sites 3 and 4 were critically modified but the multimetric analysis, Chironomidae community assessment and incidences of deformities in Chironomidae larvae indicated that site 3 is the most impacted of the four sampling sites, with least species diversity, richness, equitability and highest incidences of deformities. The study revealed the importance of multicriteria approach to environmental biomonitoring as an integrated water resources management tool, and based on the results, site 3, as the most impacted, could be prioritised for restoration intervention.

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