A Ãgua à uma substÃncia indispensÃvel para a vida, e por isso, desde a dÃcada de 1960 a sociedade exige soluÃÃes para mitigar sua deterioraÃÃo da qualidade da Ãgua. A partir de entÃo, iniciou-se o monitoramento da qualidade das Ãguas. Esse monitoramento à realizado atravÃs de Ãndices que foram e estÃo sendo desenvolvidos ou melhorados com a finalidade de sintetizar todas as caracterÃsticas das substancias presentes na Ãgua de um manancial em um Ãnico nÃmero. O Ãndice de qualidade da Ãgua mais utilizado em todo o mundo à o IQA, que foi desenvolvido em 1970 pela National Sanitation Foundation (NSF) e mais tarde foi adaptado pela Companhia de Tecnologia de Saneamento Ambiental (CETESB) para ser utilizado no Brasil. Em 2005 o Instituto de GestÃo das Ãguas de Minas (IGAM) desenvolveu um programa para determinaÃÃo do IQA, o chamado Sistema de cÃlculo de Qualidade da Ãgua (SCQA), e limitou as faixas de qualidades em intervalos diferentes das adotadas pela CETESB. Assim, com o objetivo de facilitar a tomada de decisÃo em relaÃÃo à gestÃo da qualidade das Ãguas de um manancial, foi desenvolvido nesta pesquisa um programa na plataforma Matlab que determina o valor do IQA pelas metodologias da CETESB e do IGAM/SCQA e realiza simulaÃÃes para predizer os parÃmetros que devem ser controlados para manter a atual qualidade da Ãgua e os que devem ser trabalhados (elevados ou reduzidos) para obtenÃÃo do valor do IQA desejado no manancial. O programa analisa ainda se os valores dos parÃmetros estÃo dentro das faixas de classificaÃÃo das Ãguas doces segundo a ResoluÃÃo CONAMA n 357/2005. Para simulaÃÃo foram montados trÃs cenÃrios, no primeiro o IQA pertencia a faixa de qualidade pÃssima, no segundo, o IQA pertencia a faixa de qualidade razoÃvel, segundo a metodologia de calculo do IGAM/SCQA, e a faixa de qualidade boa, de acordo com metodologia de cÃlculo da CETESB, e no terceiro cenÃrio, o IQA pertencia a faixa de qualidade de qualidade Ãtima. O programa apresentou os parÃmetros que deveriam ser trabalhados para obtenÃÃo de diferentes valores de IQA. / Water is an essential ingredient for life, and so from the 1960 society demands solutions to mitigate deterioration of water quality. Since then, it began monitoring water quality. This monitoring is performed through indexes that have been and are being developed or improved in order to synthesize all the features of these substances in the water of a fountain on a single number. The quality index of more water used worldwide is the WQI, which was developed in 1970 by the National Sanitation Foundation (NSF) and was later adapted by the Environmental Sanitation Technology (CETESB) for use in Brazil. In 2005 the Institute of Minas Water Management (IGAM) developed a program to determine the WQI, called the Water Quality Calculation system (SCQA), and limited the qualities of tracks at different intervals of the adopted by CETESB. Thus, in order to facilitate decision making for the management of water quality of a spring it was developed in this study a program in Matlab platform that determines the value of the WQI methodologies CETESB and IGAM/SCQA and performs simulations to predict the parameters that must be controlled to maintain the current water quality and that should be worked (high or low) to obtain the desired value of the WQI in spring. The program also examines whether the parameter values are within the freshwater classification ranges according to CONAMA Resolution N 357/2005. For simulation were mounted three scenarios, the first belonged to the WQI of poor quality range in the second, the WQI belonged to reasonable quality range, according to the calculation methodology of IGAM/SCQA, and good quality range, according to CETESB calculation methodology, and the third scenario, the WQI belonged to optimum quality quality range. The program presented the parameters that should be worked to obtain different values of WQI.

Orientadores: Pedro Sergio Fadini, Jose Roberto Guimarães / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-14T03:36:51Z (GMT). No. of bitstreams: 1 Fagnani_Enelton.pdf: 2480430 bytes, checksum: 9823f5e273383cbda10d238d244e3c32 (MD5) Previous issue date: 2009 / Resumo: O presente trabalho teve por finalidade avaliar alguns aspectos ambientais do Rio Jundiaí e do Ribeirão Piraí, principais mananciais da bacia do Rio Jundiaí, estado de São Paulo, uma sub-bacia do Comitê Piracicaba - Capivari - Jundiaí (PCJ), gerando um importante e inédito inventário para esse início de século, capaz de auxiliar nas tomadas de decisão sobre questões ambientais na região, valendo-se da determinação de parâmetros químicos em amostras de água e sedimento no período 2007-2008. Elegeram-se cinco pontos de coleta de água para a determinação de mercúrio total (HgT) e carbono orgânico dissolvido (COD), sendo três no Rio Jundiaí, um no Ribeirão Piraí e um no Rio Tietê, tomado como referência de locais degradados. As concentrações médias para HgT, em ng L-1, foram de 8,2 +- 6,4; 7,0 +- 6,6 e 5,2 +- 3,6 no Rio Jundiaí, 2,1 +- 1,9 no Ribeirão Piraí e 19,3 +- 13,6 no Rio Tietê. Já as concentrações médias de COD, em mg L-1, foram de 7,1 +- 1,5; 9,4 +- 2,2 e 28,6 +- 17,7 no Jundiaí, 3,3 +- 1,2 no Piraí e 14,9 +- 5,4 no Tietê. Correlações entre HgT e COD mostraram que em áreas menos impactadas, como o Ribeirão Piraí, há uma relação positiva entre o COD e o HgT, sendo que maiores valores de COD implicam na ocorrência de maiores valores de HgT; em áreas mais impactadas do Rio Jundiaí, essa relação é antagônica, sugerindo que a matéria orgânica apresenta diferenças químicas nesses dois corpos aquáticos. Com relação aos sedimentos, cinco sítios amostrais foram eleitos, quatro no Rio Jundiaí e um no Ribeirão Piraí, sendo obtidos os valores médios para sulfetos volatilizáveis por ácidos (SVA), em mmol g-1, de 0,83 +- 0,52; 3,61 +- 3,51; 5,51 +- 3,19 e 9,77 +- 6,56 no Jundiaí e 3,70 +- 1,57 no Piraí. Os demais resultados obtidos foram, respectivamente, para metais extraídos simultaneamente (MES), em ?mol g-1, de 0,63 +- 0,03; 1,19 +- 0,93; 2,66 +- 0,85; 3,73 +- 0,92 e 1,69 +- 0,35, para perdas por ignição (PPI), em porcentagem, de 6,6 +- 0,4; 5,4 +- 1,9; 14,1 +- 0,84; 14,2 +- 5,0 e 12,1 +- 2,5, e para mercúrio total (HgT), em +-g kg-1, de 40 +- ; 52 +- ; 158 +- 2; 124 +- 25 e 47 +- 12. Análises de componentes principais (PCA) foram utilizadas para relacionar os resultados obtidos nos sedimentos com as características antrópicas de cada local de coleta, revelando que áreas susceptíveis à formação de alagados se mostraram propícias ao armazenamento de metais, matéria orgânica e sulfetos lábeis, ao passo que regiões impactadas por dragagens exibiram um comportamento antagônico. A matéria orgânica se mostrou mais importante na especiação dos metais nas regiões em que houve deficiência de sulfetos, notadamente no Ribeirão Piraí, local de menor impacto antrópico. / Abstract: The present work describes environmental aspects related to Jundiaí River and Piraí Stream, both belonging to Jundiaí River basin, which is a sub-basin of the Piracicaba/Capivari/Jundiaí Watershed Committee in São Paulo, Brazil. This work generated an important and unpublished inventory regarding the region at the beginning of this century, which will be available to assist in policy decision-making that deals with environmental issues. The inventory was built up through chemical analysis in water and sediment samples during 2007-2008. In respect to water samples, 5 locations were chosen for sampling and determination of total mercury (THg) and dissolved organic carbon (DOC); 3 in Jundiaí River, 1 in Piraí Stream, and 1 in Tietê River (considered as a contaminated site reference). THg average values, in ng L-1, were 8.2 +- 6.4, 7.0 +- 6.6, and 5.2 +- 3.6 in Jundiaí River, 2.1 +- 1.9 in Piraí Stream, and 19.3 +- 13.6 in Tietê River. DOC values, in mg L-1, were 7.1 +- 1.5, 9.4 +- 2.2, and 28.6 +- 17.7 in Jundiaí River, 3.3 +- 1.2 in Piraí Stream, and 14.9 +- 5.4 in Tietê River. Correlations between THg and DOC values showed that in less influenced areas such as Piraí Stream, there was a positive correlation of these two variables, resulting in high concentrations of THg when high concentrations of DOC were determined. Otherwise, in more influenced areas such as Jundiaí River, an antagonic behavior was verified, suggesting some functional differences in organic matter present. With respect to sediments, five sampling sites were chosen, 4 in Jundiaí River and 1 in Piraí Stream. Average values obtained for acidvolatile sulfides (AVS) were 0.83 +- 0.52, 3.61 +- 3.51, 5.51 +- 3.19, and 9.77 +- 6.56 mmol g-1 in Jundiaí River and 3.70 +- 1.57 mmol g-1 in Piraí Stream. Other results obtained were, respectively, 0.63 +- 0.03, 1.19 +- 0.93, 2.66 +- 0.85, 3.73 +- 0.92, and 1.69 +- 0.35 mmol g-1 for simultaneously extracted metals (SEM); 6.6 +- 0.4, 5.4 +- 1.9, 14.1 +- 0.84, 14.2 +- 5.0, and 12.1 +- 2.5 % for loss on ignition (LOI); 40 +- 25, 52 +- 18, 158 +- 52, 124 +- 25, and 47 +- 12 mg kg-1 for THg. PCA (Principal Component Analysis) showed some relationship between results obtained for sediment samples and anthropogenic characteristics of each region studied, indicating that flooded areas were good for trapping metals, organic matter, and labile sulfides. Dredging areas were not good for this purpose. Organic matter was more important to metal speciation in sulfide-deficient areas, particularly in Piraí Stream, which presented less human impacts. / Universidade Estadual de Campi / Saneamento e Ambiente / Doutor em Engenharia Civil

O Brasil é um país dotado de grandes reservas hídricas superficiais e biodiversidade aquática, apesar de sua distribuição desigual entre as diversas regiões hidrográficas. Tendo em vista o conceito de desenvolvimento sustentável presente em diversos tratados internacionais de meio ambiente e recursos hídricos, objetivados à preservação dos ecossistemas aquáticos juntamente com a distribuição eqüitativa dos benefícios advindos da utilização dos recursos hídricos, a política nacional de recursos hídricos (Lei n° 9433/97) estabeleceu os objetivos e os instrumentos regulatórios e econômicos que norteiam a gestão hídrica brasileira, tendo por pressuposto a utilização sustentável destes recursos. Dentre os instrumentos criados para tanto, destacam-se neste trabalho a definição de padrões de qualidade para as águas superficiais, regulamentada pela Resolução CONAMA nº 20/86 e revogada pela Resolução CONAMA nº 357/05, e o enquadramento dos corpos de água superficiais, regulamentado pela Resolução CNRH n° 12/00. A partir do conhecimento sobre os novos paradigmas que estruturam os sistemas de gestão da qualidade hídrica em países com tradição em sua implementação, procurou-se desenvolver uma análise crítica do sistema de gestão da qualidade hídrica brasileiro, com enfoque para os sistemas de classificação das águas doces superficiais, considerando-se os objetivos e critérios de qualidade hídrica adotados e os sistemas de monitoramento. Para a realização dos objetivos propostos, procedeu-se à revisão bibliográfica dos documentos balizadores dos objetivos da gestão hídrica em âmbito mundial, buscando-se identificar os princípios que norteiam os sistemas de gestão da qualidade hídrica em escala global; análise dos sistemas de gestão da qualidade hídrica em países de referência, como Estados Unidos da América, Canadá, União Européia, Reino Unido, França, Austrália e Nova Zelândia, com intuito de identificar as novas tendências de gestão da qualidade hídrica; análise do sistema de gestão da qualidade hídrica brasileira nos aspectos de disponibilidades e demandas, organização institucional e legal, objetivos, parâmetros e padrões de qualidade, sistema de classificação e enquadramento dos corpos de água doce superficiais, buscando-se identificar os principais problemas e desafios de gerenciamento. Constataram-se entraves de ordem técnica, legal, econômica, social e institucional, como: falta de articulação entre os instrumentos das políticas hídrica e ambiental e entre órgãos gestores; dificuldades no estabelecimento de comitês e as agências de bacias, indispensáveis para a eficácia do sistema; incongruência entre objetivos de qualidade hídrica protetivos e a existência de classes de qualidade permissivas; desenvolvimento de padrões de qualidade hídrica considerando apenas as características físico-químicas e microbiológicas da água, em detrimento de suas características ecossistêmicas; além da defasagem no sistema de informações ambientais e no monitoramento da qualidade hídrica em todo o território. A partir do diagnóstico realizado neste trabalho, buscou-se levantar recomendações para o aperfeiçoamento do sistema tendo em vista o cumprimento dos objetivos de sustentabilidade ambiental das políticas ambiental e hídrica brasileiras. / Brazil is a country endowed with great superficial water reserves and aquatic biodiversity, despite its unequal distribution among diverse hydrographic regions. In view of the sustainable development concept established in many international environment and water treated, objectified to the aquatic ecosystems preservation and the equitable distribution of the water uses benefits, the national water policy (Law nº 9433/97) determined the objectives and the regulatory and economic instruments that guide the sustainable use of these resources. Among these instruments, are distinguished in this work those directly related to the water quality management, as the definition of superficial water quality standards, regulated in CONAMA Resolution nº 20/86 (revoked by CONAMA Resolution nº 357/05), and the superficial water bodies framing, regulated in CNRH Resolution nº 12/00. From the knowledge on the new paradigms that structuralize the water quality management systems in countries with tradition in its implementation, it was looked to develop a critical analysis of the brazilian water quality management system, under the institutional point of view and of the instruments legally constituted to implement it, with approach for the superficial freshwater classification systems, considering the objectives and criteria of water quality adopted and the monitoring systems. For the accomplishment of the objectives considered in this work, it was proceeded the bibliographical revision from documents makers of the water management objectives in a world-wide scope, searching to identify the principles that guide the water quality management systems in a global scale; analysis of water quality management systems in reference countries, as United States of America, Canada, European Union, United Kingdom, France, Australia and New Zealand, with intention to identify the new trends of water quality management; analysis of brazilian water quality management system in the aspects of availabilities and demands, institutional and legal organization, objectives, parameters and water standards, classification system and superficial freshwater framing, searching to identify the main problems and challenges of management. There were evidenced technical, legal, economic, social and institutional impediments, as: articulation lack between water and environment policies instruments and between managing agencies; difficulties in the establishment of committees and basins agencies, indispensables for the system effectiveness; incongruity among water quality protective objectives and the existence of permissive quality classes; development of water quality standards considering only the water microbiological and physicist-chemistries proprieties, disrespecting its ecosystem characteristics; beyond the imbalance in the environment information and water quality monitoring systems in all country. From the diagnosis carried through in this work, one searched to raise recommendations for the perfectioning of the system in view of the fulfilment of Brazilian water and environmental policies sustainability objectives.

M.Sc. / This study aims to assess the potential impacts of coal mine activity on exposed fish assemblages in the Mpumalanga Highveld area. A control-impact-assessment method was applied, with sites located upstream and downstream from mining activity. All sites were located in the upper Olifants catchment. Field assessments were done over a high flow and low flow period. It was ascertained that water quality variables contributing towards differences between upstream and downstream environmental conditions are salt concentrations, pH and oxygen saturation. Alterations on fish community structures indicated a categorical decline in abundances and species richness at sites situated downstream from mining activity, while Fish Response Assessment Index (FRAI) scores similarly reflected more impaired fish assemblages at downstream sites. Redundancy analysis (RDA), using fish assemblages and FRAI driver metrics explained 36.5 % of variance obtained and reflected particular alteration in Barbus neefi, B. paludinosus, Tilapia sparrmanii and Pseudocrenilabrus philander populations. Sites most severely impacted were identified, as well as the main drivers responsible for changes in fish assemblages. The Cover metric contributed significantly (p<0.05 to variance measured. Subsequent community threshold management targets are presented for problem sites, which aim to manage each site at an ecological category one class higher than the Present Ecological State (PES).

M.Sc. / The goal of the study is to investigate the role that the Local Government of the City of Johannesburg must play in the environmentally degraded Bosmont/Claremont catchment. The problem in the past was that different divisions within the Council had different responsibilities and acted in isolation from each other with regard to catchment management. Strategies were developed in this study that can be adopted by the City Council of Johannesburg and be implemented in all the catchments within its jurisdiction by all parties concerned. If these strategies prove to be successful, other local governments can also adopt it and implement them in the management of their catchments. It is thus the challenge of these strategies to provide direction for catchment management in the City Council of Johannesburg.

Magister Scientiae (Integrated Water Resource Management) / The Eerste River is a river system which has, over the years, been subjected to human interference. The purpose of this study was to investigatge temporal and spatial trends in the water quality of the Eerste River between 1990 and 2005. The study results revealed that the major trends in the water quality of the Eerste River are more spatial than temporal. / South Africa

Magister Philosophiae - MPhil / Enacted in 1998, the New South African Water Act has introduced a new approach to water resource management, founded on the principle of decentralization of the management of water resources to regional and local levels and the public participation. The approach has been captured in the new National Water Act (Act 36 of 1998), which allows the establishment of Catchment Management Agencies. The overall purpose of this study was to understand the trends of public participation in the establishment of Catchment Management Agencies in South Africa, by presenting the case of the Berg Catchment Management Agency. / South Africa

Aquatic toxicity tests are increasingly being used in water resource management worldwide, and currently in South Africa, policy and legislation are being drafted to reflect this international trend. While standard toxicity test methods and test organisms are being considered to develop and set water quality guidelines and effluent discharge limits, it is not clear whether guidelines and discharge limits set using these standard test organisms will be sufficient to protect South Africa’s scarce water resources. As part of ongoing research to investigate the use of indigenous riverine organisms as toxicity test organisms a number of potential species have been identified, including the freshwater shrimp Caridina nilotica. For much of the history of aquatic toxicological data the bulk of the data has been generated by acute toxicity testing, based on short exposures and using mortality as the response end point. There are relatively few chronic, longterm tests with sub-lethal endpoints. However, it was recognized that information about longer exposure durations and non lethal response endpoints was needed, instead of mortality. Chronic tests can provide a more environmentally realistic measure of chemical toxicity than acute toxicity tests. Caridina nilotica has been identified as a potential standard toxicity test organism, as it is widely distributed, easy to find and it occurs in flowing waters. It is an indigenous species which can be easily cultured and maintained in the laboratory and is also ecologically important. Both adults and juveniles have been used successfully in acute toxicity tests at the Institute for Water Research (Rhodes University) and the ability to rear the organisms under laboratory conditions has allowed the development of chronic toxicity tests using C. nilotica. Chronic early life stage tests include continuous exposure of the early life stages, which are presumed to be the most sensitive for aquatic organisms. This study reports on the embryonic development of C. nilotica at the culture temperature of 24⁰C. Morphological developmental stages were monitored and measured and 7 developmental stages were identified. Based on the measurements of the features that were identified, toxicity tests using the reference chemicals sodium chloride (NaCl), sodium sulphate (Na₂SO₄) and cadmium chloride (CdCl₂) were undertaken to test the suitability of C. nilotica embryonic development for chronic toxicity tests for use in water resource management. The length, width, length:width ratios and area of the features decreased in size when exposed to the chemicals. The Lowest Observed Effect Concentration (LOEC) values were 2000mg/L for Na₂SO₄, 3000mg/L for NaCl and 0.31mg/L for CdCl₂. The No Observed Effect Concentration (NOEC) values were 1000mg/L for Na₂SO₄, 2000mg/L for NaCl and <0.31mg/L for CdCl₂. Further research on the teratogenic effects of single chemicals and industrial effluent on developing C. nilotica embryos needs to be undertaken in order to evaluate the described test protocol for use in water resource management.

The availability of adequate information is one of the basic requirements of sound water resources development. Simple water resource development options that required less detailed studies have already been developed, such that development proposals today require more detailed and comprehensive studies. Among other factors, these studies generate information on the hydrological risk of implementing water resources projects. The modelling tools used to generate water resources information are usually complicated by the many variables involved, which are inter-linked and usually unpredictable. The National Water Act (Republic of South Africa, 1998) emphasises the need for integrated water resources management, social equity, and ecological sustainability, which have added new dimensions to water resources planning. Water catchment simulation models that account for all the dimensions of water resources planning and bring more information than ever before to the decision-maker have become the preferred tools. Whilst earlier water resources planning tools are still in common use, this study found that these earlier tools lagged behind developments in important aspects such as national legislation, water stakeholders’ working environment, and rapid changes in computer software and hardware. The appropriateness of water resources modelling tools in South Africa was investigated in the light of a changing water environment as well as the need to address specific factors that are unique to South Africa. The water resources factors investigated included hydro-climatic, water institutional frameworks and stakeholder needs, available expertise and technological aspects of the available water management and planning tools. On the basis of the outcome of the investigation of South Africa’s unique water environment, recommendations and guidance were developed with the aim of developing a preferred local water resources modelling approach. This study investigated and recommended the use of water resources system models which are based on up to date modelling and Information Technology (IT) developments, such as HYDRO25, for multi-criteria planning of integrated water resources. In this study, the development of object oriented programming (OOP) models with visual interfaces that fit in the popular Windows operating environment was distinguished as a key aspect of water resources modelling. This modelling route was selected because it generates tools that are more user-friendly, have visual clues that relate closely with the physical system, including easy GIS integration, can handle the higher computer memory volume demands of longer time series data, and could handle a greater number of parameters as well as the increasingly more complex management scenarios. In the OOP approach, modelling tools are easily integrated with the input processing and output analysis objects that are developed separately before integration into the main model framework. All the separate software objects can easily be utilised in other models when the need arises. The HYDRO25 model uses modular objects and a visual-based programming language that easily accommodates integration with other software objects based on the component object model system. This has made further upgrading and redevelopment of the model easy to handle. In this study, the HYDRO25 model was developed and used in the Doring River catchment as a case study which was aimed at providing first-hand information about model development and application in South Africa. In the HYDRO25 model, computer code was used systematically to handle the catchment hydrology, geographical information, climatic factors, water use, catchment development proposals, the requirement of water legislation, and other factors to provide information that is useful for decision-making. In the Doring River case study, proposed irrigation developments in the Koue Bokkeveld and Aspoort area of the Western Cape were assessed using the HYDRO25 model to determine the most viable development options from a hydrological perspective. The study showed that the full irrigation potential of the catchment cannot be utilised with the available surface water resources in the catchment. The model simulation results showed that a maximum of 700 hectares can be irrigated in the Koue Bokkeveld area without creating additional water storage. Analysis of the Aspoort irrigation scheme showed that the irrigation area should be limited to 1000 hectares, with the proposed 178 million m3 Aspoort Dam being developed to support irrigation water demand and, to a small extent, to contribute to other water uses in the catchment, such as ecological flows and domestic uses. / Thesis (PhD (Water Resources Management))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

South Africa, like the rest of the world, is vulnerable to the impact of climate change and loss of biodiversity. Water pollution is one of the six global threats to freshwater biodiversity. The future health status and productivity of South Africa’s estuaries is dependent on two main factors: management and quality and quantity of freshwater inputs. South Africa has around 250 functioning estuaries along its 3000 km coastline (Hosking 2004). They play an invaluable role in ecosystem functioning and biodiversity conservation. Estuaries are amongst the richest and most productive parts of the marine environment and as such call for careful management. Some of these ecosystems are focus areas for urban an industrial development. Urbanization and industrialization pose a serious threat to these sensitive systems. Increased water pollution from domestic use, industry and agriculture affect the ecology of these estuarine, river and lake systems. A large number of South African estuaries are still in excellent or good condition, but these are mainly the very small systems. The larger systems, like the Swartkops estuary, often very important in terms of conservation value, are also often compromised in some way or other. The reasons why they are compromised include habitat destruction, artificial breaching and pollution, especially those close to urban areas. This situation is aggravated by outdated and inadequate sewage treatment plant infrastructure and unskilled operators that dispose untreated waste into these systems. Pollution into estuaries can result in the partial loss of the environmental service flows supplied by them. The result of lost environmental service flows has adverse consequences, such as diminished residential and holiday recreational appeal, as well as reduced capacity to support subsistence livelihoods. Poor water quality not only limits its utilisation value, but is also places added economic burden on society, through both the primary treatment costs and the secondary impacts on the economy. Healthy estuarine ecosystems are essential for the maintenance of biodiversity and a wide range of environmental goods and services. Without a drastic improvement in water quality management approaches and treatment technologies, the continuous deterioration in water quality will decrease benefits and increase costs affiliated with use of these water resources.The market-based system of the South African economy has to a large extent failed to account for the value of the “free” goods and services provided by the natural environment. When the true value of the natural resources is unknown, there is a risk that less financial resources and capacity are made available to manage and protect these natural resources than is efficient. To ensure that these goods are properly taken into account, they must be valued and these values incorporated in social decision making. This study uses the contingent valuation method (CVM) to establish the value of the Swartkops estuary for changes to water quality. The CVM is a non-market valuation method that is widely used in cost-benefit analysis and environmental impact assessment. The CVM establishes the economic value of the good by asking the users of an environmental good to state their willingness to pay for a hypothetical scenario to prevent, or bring about, certain changes in the current condition of the environmental good. This method is subjected to some criticism. This criticism revolves around the validity and the reliability of estimated results and the effects of various biases and errors on them. The North Oceanic and Atmospheric Administration (NOAA) Blue-Ribbon panel investigating the validity of the CVM resolved that the CVM can be used to guide social decision making, if a series of guidelines are followed. The Swartkops contingent valuation (CV) was conducted with these guidelines in mind. The results of the Swartkops CV indicate that the user population has a total willingness to pay (TWTP) of R68848 (median bid) and R203632 (mean bid) annually for the implementation of a project to improve the water quality in the Swartkops estuary. User population is an important determinant of the TWTP value. As a result, using a more broadly defined user population, TWTP per annum was calculated to be R3481987 (median bid) and R10298688 (mean bid). Management of natural resources should be informed by values that reflect efficient balances, so as to obtain the most efficient use of them (Trupie 2008). Polluted water inflows into South Africa’s estuaries are a threat to their biodiversity. Healthy estuarine ecosystems are essential for the maintenance of biodiversity and human well-being (Water Assessment Programme Report 2006: 15). As a result, this study recommends that a project be implemented by the Nelson Mandela Bay Municipality to improve water quality in the Swartkops estuary.