Farmyard runoff, i.e. the effluent generated by the rain falling over farmyards, tracks and roofs, is a significant and overlooked source of nutrients and pathogens which degrades aquatic ecosystems through eutrophication, siltation and wildlife poisoning, raises public health concerns, and incurs considerable costs for society. Among other Best Management Practices implemented to address agricultural water pollution and help achieve compliance with the Water Framework Directive, Constructed Farm Wetlands (CFWs), i.e. shallow surface flow wetlands comprising several vegetated cells in series, are being recommended for remediation of farmyard runoff, due to their capacity to remove or store pollutants. Investigation is therefore needed of their long-term water treatment efficiency and ecological value to optimize their design and cost-effectiveness and minimize their negative externalities. The main aims of this study were to: 1) evaluate the treatment performance of CFWs and the link between design, hydrology and efficiency; 2) assess their ecological value and the influence of water quality and design on wetland ecology; 3) identify their costs, benefits and the way they are perceived by farmers; and 4) inform guidelines for the design, construction and aftercare of sustainable CFWs. Research focused on two CFWs in south-east Scotland, one at a dairy farm and one at a mixed beef-arable farm, which receive runoff from yards and roofs, field drainage and septic tank overflow. From February 2006 to June 2008, rainfall, evaporation, water levels and flow at the CFWs were monitored, and their treatment efficiency was assessed from water samples collected manually regularly or with automatic samplers during storm events, and analysed using standard methods. In addition, their ecological value was assessed twice a year from vegetation and aquatic macroinvertebrate surveys. Finally, semi-structured interviews with eight farmers and a farm advisor and discussions with three CFW designers in Scotland and Ireland allowed collection of technical and economic data on farm practices, CFW construction and maintenance, and helped assess CFW cost-effectiveness and acceptance by farmers. Both CFWs reduced pollutant concentrations between inlet and outlet, with efficiencies at CFW1 and CFW2 respectively of 87% and < 0% for five-day biochemical oxygen demand, 86% and 83% for suspended solids, 68% and 26% for nitrate/nitrite, 42% and 34% for ammonium, and 12% and 31% for reactive phosphorus. Nevertheless, the concentration of all pollutants at the outlet of CFW1, and concentration of nitrate/nitrite at the outlet of CFW2 frequently exceeded river water quality standards. Water treatment efficiency varied seasonally, being significantly lower in winter, mainly due to lower temperatures, increased volume of inputs and reduced residence time. The ecological value of the two CFWs differed greatly. At CFW1 and CFW2 respectively, 14 and 22 wetland plant species and 24 and 46 aquatic macroinvertebrate species (belonging to 13 and 27 BMWP scoring families respectively) were recorded, illustrating the greater biodiversity conservation value of CFW2, which was one year older, larger, cleaner, comprised several ponds with a combination of open water and densely vegetated areas, and was subsequently more structurally diverse. The socio-economic study revealed that, despite significant costs associated with their construction (£20 000-£50 000 ha-1) and maintenance (£900-£1500 ha-1 yr-1), CFWs may still represent a more cost-effective alternative than conventional methods. However, their adoption, implementation and sustainable use by farmers were conditioned by land availability and suitability, existing farm infrastructure, detailed information on limitations and maintenance requirements, and adequate financial support for both construction and aftercare. To ensure a long-term, consistent and efficient water treatment, and to enhance biodiversity and landscape, well-maintained, large, vegetated, multi-cell CFWs with shallow overflows are recommended. Their size should be adapted to local precipitation patterns and catchment characteristics. Keywords: agriculture, best management practice (BMP), biodiversity, constructed farm wetland (CFW), costs, farmyard runoff, water pollution, water treatment.

Based on many years of water quality (including algal) and water treatment cost data, available at Umgeni Water, a study was undertaken to better understand the water quality relationships in man made lakes within the company's operational area, and to investigate how water quality affected the cost of treating water from these lakes. The broad aims to the study were to: identify the key environmental variables that were affecting algal populations in lakes; and if these were significant to establish predictive models relating algae to the water quality; and to develop models relating the water quality in lakes to the cost of treating water from the lakes. Semi-quantitative models were developed relating algal abundances with important environmental variables. In most cases, the models developed were related to algal populations that were known to adversely affect water treatment. Direct algal impact on water treatment processes was through the production of either taste and odour forming compounds (requiring advanced water treatment, such as use of activated carbon), or their ability to clog sand filters and so reduce filter run times (requiring more frequent backwashing of filters). Thereafter lake water quality parameters (which included water physico-chemistry and algae) were investigated to determine which factors were most significantly impacting on water treatment and hence treatment costs at selected water works (WW) within the Umgeni Water operational area. Models were developed relating raw water quality entering respective water works with costs incurred in treating that water. The models allowed simulations to be developed illustrating how changes in water quality might impact on water treatment costs. The impact of eutrophication and contamination of rivers and lakes, and its subsequent impact on surface water resources, was quantified. / Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2004.

Based on many years of water quality (including algal) and water treatment cost data, available at Umgeni Water, a study was undertaken to better understand the water quality relationships in man made lakes within the company's operational area, and to investigate how water quality affected the cost of treating water from these lakes. The broad aims to the study were to: identify the key environmental variables that were affecting algal populations in lakes; and if these were significant to establish predictive models relating algae to the water quality; and to develop models relating the water quality in lakes to the cost of treating water from the lakes. Semi-quantitative models were developed relating algal abundances with important environmental variables. In most cases, the models developed were related to algal populations that were known to adversely affect water treatment. Direct algal impact on water treatment processes was through the production of either taste and odour forming compounds (requiring advanced water treatment, such as use of activated carbon), or their ability to clog sand filters and so reduce filter run times (requiring more frequent backwashing of filters). Thereafter lake water quality parameters (which included water physico-chemistry and algae) were investigated to determine which factors were most significantly impacting on water treatment and hence treatment costs at selected water works (WW) within the Umgeni Water operational area. Models were developed relating raw water quality entering respective water works with costs incurred in treating that water. The models allowed simulations to be developed illustrating how changes in water quality might impact on water treatment costs. The impact of eutrophication and contamination of rivers and lakes, and its subsequent impact on surface water resources, was quantified. / Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2004.

A sociedade necessita de indicadores capazes de medir a susceptibilidade ao risco de degradação de um manancial de abastecimento público. O percentual de cobertura florestal de uma bacia hidrográfica pode ser utilizado como um dos indicativos na avaliação da qualidade de um manancial de abastecimento público. O custo do tratamento de águas provenientes de bacias hidrográficas com diferentes percentuais de cobertura florestal é um componente que pode subsidiar discussões sobre a importância da cobertura florestal em mananciais de abastecimento público, como recurso ambiental a ser priorizado pelo poder público e exigido pela sociedade, tendo em vista os benefícios econômicos e de minimização de riscos à saúde humana. O trabalho determinou os custos do tratamento da água proveniente de bacias hidrográficas com diversos percentuais de cobertura florestal através da análise das características operacionais de diversas Estações de Tratamento de Água (ETAs) e suas respectivas captações. Para seis dos sete sistemas e ETAs estudadas, o custo específico com produtos químicos na ETA eleva- se com a redução do percentual de cobertura florestal da bacia de abastecimento. Não se pretendeu situar e associar a localização das áreas de cobertura florestal a outros fatores como, por exemplo, a susceptibilidade do solo à erosão ou ao percentual de área florestada situada em APP’s. Considerando-se o enfoque do trabalho sobre a qualidade de mananciais de abastecimento público e a relevância do episódio de rejeição do rio Piracicaba no ano 2000 como principal manancial de abastecimento público do município de mesmo nome, em decorrência da perda de qualidade de suas águas, dos altos custos do tratamento e da impossibilidade de garantir água de consumo humano de qualidade , o trabalho teve por objetivo também analisar as perspectivas para a qualidade das águas do rio Corumbataí, novo manancial eleito para Piracicaba. Utilizou-se como recurso a análise de dados de caracterização física das bacias e sócio-econômica dos municípios das bacias dos rios Piracicaba e Corumbataí, e da qualidade das águas dos rios Piracicaba e Corumbataí. O estudo faz uma reflexão sobre o atual arranjo de instituições públicas, suas atribuições legais e ferramentas para a aplicação de leis e implementação de ações de planejamento regional nas bacias dos rios Corumbataí e Piracicaba. / The Society needs to be able to check when a water source for public supply is about to reach a degradation level. The percentage off forest covered in the watershed can be used as one of the indicators to measure the quality of a public water source. The cost of water treatment from different water supply areas containing different percentage of soil forest cover, is a component that can be brought into discussions about the importance of the forest cover in drinking water public supply areas, as an environmental natural resource, to be prioritized by the Authorities, and mandatory by the Society, heading to both economical benefits and the human health risks minimization. This work has determined the costs of water treatment from water supply areas with different percentages of natural forest cover, analysis of all operating data of all Treatment Water Stations (ETAs), as well as their water sources. For six out of seven studied systems and ETAs, the specific cost with chemical products in one ETA increases with the reduction of the known portion of rain forest for the watershed. Certainly this study was not intended to try to associate the forest location areas to other factors, as for example, the erosion soil characteristic or to the portion of forest cover, located in riparian areas. Considering the focus of this work about the public supply of drinking water and the recent episode of the Piracicaba river rejection as the main water supply for the Region in year 2000, because of the low level quality of its water, the high treatment costs, and the impossibility to make feasible to count on it to distribute good quality water, this work had also the purpose of analyzing the perspectives for the Corumbataí river, to be elected as the main source of water supply for Piracicaba. Socio-economic of all cities along the river basins of Piracicaba and Corumbataí has been studied. Besides the organization of all administrative offices in charge with the problem, their legal functions and possible available tools to plan and to work properly, has also been analyzed.

A sociedade necessita de indicadores capazes de medir a susceptibilidade ao risco de degradação de um manancial de abastecimento público. O percentual de cobertura florestal de uma bacia hidrográfica pode ser utilizado como um dos indicativos na avaliação da qualidade de um manancial de abastecimento público. O custo do tratamento de águas provenientes de bacias hidrográficas com diferentes percentuais de cobertura florestal é um componente que pode subsidiar discussões sobre a importância da cobertura florestal em mananciais de abastecimento público, como recurso ambiental a ser priorizado pelo poder público e exigido pela sociedade, tendo em vista os benefícios econômicos e de minimização de riscos à saúde humana. O trabalho determinou os custos do tratamento da água proveniente de bacias hidrográficas com diversos percentuais de cobertura florestal através da análise das características operacionais de diversas Estações de Tratamento de Água (ETAs) e suas respectivas captações. Para seis dos sete sistemas e ETAs estudadas, o custo específico com produtos químicos na ETA eleva- se com a redução do percentual de cobertura florestal da bacia de abastecimento. Não se pretendeu situar e associar a localização das áreas de cobertura florestal a outros fatores como, por exemplo, a susceptibilidade do solo à erosão ou ao percentual de área florestada situada em APP’s. Considerando-se o enfoque do trabalho sobre a qualidade de mananciais de abastecimento público e a relevância do episódio de rejeição do rio Piracicaba no ano 2000 como principal manancial de abastecimento público do município de mesmo nome, em decorrência da perda de qualidade de suas águas, dos altos custos do tratamento e da impossibilidade de garantir água de consumo humano de qualidade , o trabalho teve por objetivo também analisar as perspectivas para a qualidade das águas do rio Corumbataí, novo manancial eleito para Piracicaba. Utilizou-se como recurso a análise de dados de caracterização física das bacias e sócio-econômica dos municípios das bacias dos rios Piracicaba e Corumbataí, e da qualidade das águas dos rios Piracicaba e Corumbataí. O estudo faz uma reflexão sobre o atual arranjo de instituições públicas, suas atribuições legais e ferramentas para a aplicação de leis e implementação de ações de planejamento regional nas bacias dos rios Corumbataí e Piracicaba. / The Society needs to be able to check when a water source for public supply is about to reach a degradation level. The percentage off forest covered in the watershed can be used as one of the indicators to measure the quality of a public water source. The cost of water treatment from different water supply areas containing different percentage of soil forest cover, is a component that can be brought into discussions about the importance of the forest cover in drinking water public supply areas, as an environmental natural resource, to be prioritized by the Authorities, and mandatory by the Society, heading to both economical benefits and the human health risks minimization. This work has determined the costs of water treatment from water supply areas with different percentages of natural forest cover, analysis of all operating data of all Treatment Water Stations (ETAs), as well as their water sources. For six out of seven studied systems and ETAs, the specific cost with chemical products in one ETA increases with the reduction of the known portion of rain forest for the watershed. Certainly this study was not intended to try to associate the forest location areas to other factors, as for example, the erosion soil characteristic or to the portion of forest cover, located in riparian areas. Considering the focus of this work about the public supply of drinking water and the recent episode of the Piracicaba river rejection as the main water supply for the Region in year 2000, because of the low level quality of its water, the high treatment costs, and the impossibility to make feasible to count on it to distribute good quality water, this work had also the purpose of analyzing the perspectives for the Corumbataí river, to be elected as the main source of water supply for Piracicaba. Socio-economic of all cities along the river basins of Piracicaba and Corumbataí has been studied. Besides the organization of all administrative offices in charge with the problem, their legal functions and possible available tools to plan and to work properly, has also been analyzed.