Water quantity, availability and, particularly, quality of Brazilian freshwater is under progessive degradation due to Anthropocene\'s environmental changing conditions. Strategies of Ecosystem-based Adaptation (EbA) are essential to mitigate these impacts. This Ph.D. thesis proposes a new model of water resources management, thereby integrating selfpurification and ecohydrologic processes to evaluate ecosystem services from watershed under change. In Chapter 2, this thesis examinates the payment for hydrologic cosystem services (Water-PES) in Brazilian Atlantic Forest and points ecohydrologic variables useful for assessing and further valuing hydrologic services. In Chapter 3, this thesis discusses proposals for freshwater monitoring plan which integrate quali-quantitative aspects for EbA and Water-PES projects. Therefore, in Chapter 4 experimental quali-quantative freshwater data from in-situ field observations are investigated according land-use/land-cover (LULC) in headwaters of water supply systems. In Chapter 5, through simulated impacts on freshwater yield from scenarios of LULC change, the grey water footprint (greyWF) is assessed, as well as environmental sustainability of sub-basins is depicted from a new ecohydrologic index for assessing hydrologic services. The methodology is performed using through field sampling and lab-analysing of physico-chemical, biologic and hydraulic variables in nested sub-basins draining to the Cantareira Water Supply System, in Sao Paulo and Minas Gerais states, Brazil. These areas participate in the Water-PES projects Water Producer/PCJ and Water Conservator at headwaters of Piracicaba watershed, during recent severe drought conditions between years 2013-15. The greyWF is estimated from outputs of time series simulated through ecohydrologic model Soil and Water Assessment Tool (SWAT). Under assumption of continuity of Water-PES projects, and using the same series of hydrometorological records for a common period (2008-2014), freshwater quali-quantitative impacts are performed through three LULC scenarios: past situation \"S1\" (year 1990), current situation \"S2\" (year 2010) and future situation \"S2+EbA\" (year 2035). From these scenarios, flow and load duration curves, mean water yields, greyWF and seasonal variabilities, were simulated. Through this research, continuous-monitoring Data Collecting Stations were installed in public-private partnership encompassing EESC/USP, ANA, CPRM, CEMADEN, SMA, TNC, WWF and local mayors. This continuous monitoring is addressed to increase the system resilience, based on better decision-making for water security, in strategic headwaters not only for water supply, but also for environmental conservation. This doctoral thesis brings contributions to a better comprehension of anthropic impacts on water resources and for strategies of EbA in front of progressive rates of losses of ecosystem services. This PhD. thesis was part of three research initiatives which partly granted activities: (1) Thematic Project FAPESP 2008/58161-1 \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and Strategies for Adaptation Options\"; (2) \"INCLINE - INterdisciplinary CLimate INvEstigation Center\" (NapMC/USP Núcleo de Apoio às Pesquisas em Mudanças Climáticas) and (3) \"Água Brasil\" Project, Banco do Brasil Foundation, WWF Brazil, ANA & FIPAI/EESC-USP. / A quantidade, a disponibilidade e, em particular, a qualidade da água doce está em degradação progressiva devido às mudanças ambientais no Antropoceno. Estratégias de adaptação baseadas em ecossistemas (EbA) são essenciais para reduzir estes impactos. Propõe-se um novo modelo de gerenciamento de recursos hídricos que integre a pegada hídrica cinza e processos ecohidrológicos para avaliação dos serviços hidrológicos em bacias hidrográficas sob mudanças. As etapas da pesquisa são: Capítulo 2 – análise dos projetos de pagamentos por serviços ambientais de proteção às bacias hidrográficas na Mata Atlântica brasileira e, no contexto de EbA, indicação de variáveis ecohidrológicas úteis na quantificação e futura valoração dos serviços hidrológicos; Capítulo 3 – desenvolvimento de plano de monitoramento ecohidrológico que integra aspectos qualitativos e quantitativos dos recursos hídricos para projetos de EbA; Capítulo 4 – provisão de dados experimentais de qualidade e quantidade da água, além de observações in-situ, para investigação das influências das mudanças de uso e ocupação do solo nas cabeceiras de mananciais, estratégicos para o abastecimento público e a conservação ambiental; Capítulo 5 – estimativas da pegada hídrica cinza para nitrato, fósforo total e sedimentos a partir do monitoramento de variáveis quali-quantitativas em bacias com diferentes condições de uso e ocupação de solo. Foi realizada a instalação de três Plataformas de Coleta de Dados, por meio de parceria entre EESC, ANA, CPRM, CEMADEN, SMA, TNC e WWF, visando aumentar a resiliência do sistema, decorrente de futuro aprimoramento da gestão, para a segurança hídrica. A metodologia incluiu coletas em seis diferentes períodos, durante dois anos, e análises das variáveis condutividade elétrica, cor, DQO, DBO5,20, nitrato, nitrito, nitrogênio amoniacal, fosfato, pH, turbidez, sólidos totais, coliformes termotolerantes, Escherichia coli, medidas de vazões e velocidades médias em seções transversais. O método foi aplicado em microbacias participantes dos projetos Produtor de Água/PCJ e Conservador das Águas, dentre outras, com áreas de drenagem entre 7 e 1.000 km2, que contribuem para a bacia do rio Piracicaba (12.530 km2). Dados primários, medidos em recente período de severa estiagem no Sistema Cantareira (2013-14), foram integrados aos bancos de dados de órgãos gestores federais e estaduais. A produção de água foi maior em sub-bacias menos florestadas. Foi possível aprimorar a regionalização de cargas poluidoras por área de drenagem na região do Cantareira. A pegada hídrica cinza (WF) foi estimada a partir de simulações no modelo ecohidrológico Soil and Water Assessment Tool (SWAT). Curvas de permanência de vazões e carga poluidora por área de drenagem foram elaboradas. Supondo-se a continuidade dos projetos \"Produtor de Água/PCJ\" e \"Conservador das Águas\", foram investigados os impactos de cenário futuro de uso do solo. Finalmente, foi desenvolvido novo índice ecohidrológico para quantificação dos serviços hidrológicos e avaliação a sustentabilidade das sub-bacias, a partir da pegada hídrica cinza composta. Assim, usando ferramentas de vanguarda tecnológica (SWAT e WF), a tese fornece subsídios para uma melhor compreensão dos impactos antropogênicos sobre os recursos hídricos e novas estratégias de adaptação baseada em ecossistemas, frente às progressivas taxas de perda de serviços ambientais. Esta tese esteve vinculada a três projetos de pesquisa, dos quais obteve apoio financeiro: (1) Projeto Temático FAPESP 2008/58161-1 \"Assessment of Impacts and Vulnerability to Climate Change in Brazil & Strategies for Adaptation Options\"; (2) \"INCLINE - INterdisciplinary CLimate INvEstigation Center\" (NapMC/USP) e (3) Projeto \"Água Brasil\", Fundação Banco do Brasil, WWF Brasil, ANA e FIPAI/EESC-USP.

Water quantity, availability and, particularly, quality of Brazilian freshwater is under progessive degradation due to Anthropocene\'s environmental changing conditions. Strategies of Ecosystem-based Adaptation (EbA) are essential to mitigate these impacts. This Ph.D. thesis proposes a new model of water resources management, thereby integrating selfpurification and ecohydrologic processes to evaluate ecosystem services from watershed under change. In Chapter 2, this thesis examinates the payment for hydrologic cosystem services (Water-PES) in Brazilian Atlantic Forest and points ecohydrologic variables useful for assessing and further valuing hydrologic services. In Chapter 3, this thesis discusses proposals for freshwater monitoring plan which integrate quali-quantitative aspects for EbA and Water-PES projects. Therefore, in Chapter 4 experimental quali-quantative freshwater data from in-situ field observations are investigated according land-use/land-cover (LULC) in headwaters of water supply systems. In Chapter 5, through simulated impacts on freshwater yield from scenarios of LULC change, the grey water footprint (greyWF) is assessed, as well as environmental sustainability of sub-basins is depicted from a new ecohydrologic index for assessing hydrologic services. The methodology is performed using through field sampling and lab-analysing of physico-chemical, biologic and hydraulic variables in nested sub-basins draining to the Cantareira Water Supply System, in Sao Paulo and Minas Gerais states, Brazil. These areas participate in the Water-PES projects Water Producer/PCJ and Water Conservator at headwaters of Piracicaba watershed, during recent severe drought conditions between years 2013-15. The greyWF is estimated from outputs of time series simulated through ecohydrologic model Soil and Water Assessment Tool (SWAT). Under assumption of continuity of Water-PES projects, and using the same series of hydrometorological records for a common period (2008-2014), freshwater quali-quantitative impacts are performed through three LULC scenarios: past situation \"S1\" (year 1990), current situation \"S2\" (year 2010) and future situation \"S2+EbA\" (year 2035). From these scenarios, flow and load duration curves, mean water yields, greyWF and seasonal variabilities, were simulated. Through this research, continuous-monitoring Data Collecting Stations were installed in public-private partnership encompassing EESC/USP, ANA, CPRM, CEMADEN, SMA, TNC, WWF and local mayors. This continuous monitoring is addressed to increase the system resilience, based on better decision-making for water security, in strategic headwaters not only for water supply, but also for environmental conservation. This doctoral thesis brings contributions to a better comprehension of anthropic impacts on water resources and for strategies of EbA in front of progressive rates of losses of ecosystem services. This PhD. thesis was part of three research initiatives which partly granted activities: (1) Thematic Project FAPESP 2008/58161-1 \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and Strategies for Adaptation Options\"; (2) \"INCLINE - INterdisciplinary CLimate INvEstigation Center\" (NapMC/USP Núcleo de Apoio às Pesquisas em Mudanças Climáticas) and (3) \"Água Brasil\" Project, Banco do Brasil Foundation, WWF Brazil, ANA & FIPAI/EESC-USP. / A quantidade, a disponibilidade e, em particular, a qualidade da água doce está em degradação progressiva devido às mudanças ambientais no Antropoceno. Estratégias de adaptação baseadas em ecossistemas (EbA) são essenciais para reduzir estes impactos. Propõe-se um novo modelo de gerenciamento de recursos hídricos que integre a pegada hídrica cinza e processos ecohidrológicos para avaliação dos serviços hidrológicos em bacias hidrográficas sob mudanças. As etapas da pesquisa são: Capítulo 2 – análise dos projetos de pagamentos por serviços ambientais de proteção às bacias hidrográficas na Mata Atlântica brasileira e, no contexto de EbA, indicação de variáveis ecohidrológicas úteis na quantificação e futura valoração dos serviços hidrológicos; Capítulo 3 – desenvolvimento de plano de monitoramento ecohidrológico que integra aspectos qualitativos e quantitativos dos recursos hídricos para projetos de EbA; Capítulo 4 – provisão de dados experimentais de qualidade e quantidade da água, além de observações in-situ, para investigação das influências das mudanças de uso e ocupação do solo nas cabeceiras de mananciais, estratégicos para o abastecimento público e a conservação ambiental; Capítulo 5 – estimativas da pegada hídrica cinza para nitrato, fósforo total e sedimentos a partir do monitoramento de variáveis quali-quantitativas em bacias com diferentes condições de uso e ocupação de solo. Foi realizada a instalação de três Plataformas de Coleta de Dados, por meio de parceria entre EESC, ANA, CPRM, CEMADEN, SMA, TNC e WWF, visando aumentar a resiliência do sistema, decorrente de futuro aprimoramento da gestão, para a segurança hídrica. A metodologia incluiu coletas em seis diferentes períodos, durante dois anos, e análises das variáveis condutividade elétrica, cor, DQO, DBO5,20, nitrato, nitrito, nitrogênio amoniacal, fosfato, pH, turbidez, sólidos totais, coliformes termotolerantes, Escherichia coli, medidas de vazões e velocidades médias em seções transversais. O método foi aplicado em microbacias participantes dos projetos Produtor de Água/PCJ e Conservador das Águas, dentre outras, com áreas de drenagem entre 7 e 1.000 km2, que contribuem para a bacia do rio Piracicaba (12.530 km2). Dados primários, medidos em recente período de severa estiagem no Sistema Cantareira (2013-14), foram integrados aos bancos de dados de órgãos gestores federais e estaduais. A produção de água foi maior em sub-bacias menos florestadas. Foi possível aprimorar a regionalização de cargas poluidoras por área de drenagem na região do Cantareira. A pegada hídrica cinza (WF) foi estimada a partir de simulações no modelo ecohidrológico Soil and Water Assessment Tool (SWAT). Curvas de permanência de vazões e carga poluidora por área de drenagem foram elaboradas. Supondo-se a continuidade dos projetos \"Produtor de Água/PCJ\" e \"Conservador das Águas\", foram investigados os impactos de cenário futuro de uso do solo. Finalmente, foi desenvolvido novo índice ecohidrológico para quantificação dos serviços hidrológicos e avaliação a sustentabilidade das sub-bacias, a partir da pegada hídrica cinza composta. Assim, usando ferramentas de vanguarda tecnológica (SWAT e WF), a tese fornece subsídios para uma melhor compreensão dos impactos antropogênicos sobre os recursos hídricos e novas estratégias de adaptação baseada em ecossistemas, frente às progressivas taxas de perda de serviços ambientais. Esta tese esteve vinculada a três projetos de pesquisa, dos quais obteve apoio financeiro: (1) Projeto Temático FAPESP 2008/58161-1 \"Assessment of Impacts and Vulnerability to Climate Change in Brazil & Strategies for Adaptation Options\"; (2) \"INCLINE - INterdisciplinary CLimate INvEstigation Center\" (NapMC/USP) e (3) Projeto \"Água Brasil\", Fundação Banco do Brasil, WWF Brasil, ANA e FIPAI/EESC-USP.

Irrigated agriculture accounts for 90 percent of consumptive use of freshwater in the western US and is considered the largest contributor to nonpoint source water pollution. The diffuse nature of most water quality and quantity challenges necessitates institutions that can more effectively engage agricultural producers in strategic, integrated, watershed-scale approaches to water management such as those associated with Integrated Water Resource Management (IWRM). With approximately 9,400 professionals working in nearly every one of the nation's 3,071 counties and an emphasis on voluntary, incentives-based approaches to conservation, the Natural Resources Conservation Service (NRCS) is well poised to influence land and water management on private working lands. NRCS conservation programs, however, have been criticized as "random acts of conservation" that lack a strategic vision for addressing natural resource challenges at-scale. Using NRCS's new Agricultural Water Enhancement Program (AWEP) as a case study, this paper seeks to examine the factors that enable or inhibit NRCS from promoting an integrated approach to water management consistent with IWRM principles. Following the Institutional Analysis and Development (IAD) framework this paper traces the development of AWEP and examines how the rules established at the national level impact implementation at the national, state and local levels. The paper then evaluates AWEP based on a set of six IWRM design principles to determine (a) the extent to which AWEP represents an IWRM approach, and (b) the institutional factors that facilitate or inhibit NRCS from taking a more integrated approach to water management. I found that institutional factors vary greatly between levels of analysis depending on the specific context, but did identify several consistent enablers and barriers. The three most significant factors that facilitate an IWRM approach are: (1) AWEP's focus on priority resource concerns within a defined hydrographic area; (2) AWEP's emphasis on pursuing a partnership-based approach; and (3) increased local involvement in defining projects. The three most significant factors that inhibit an IWRM approach are: (1) a lack of clarity concerning partner roles and responsibilities and constraints on partner involvement; (2) limited flexibility of existing program rules; and (3) limited local capacity to engage with landowners and implement projects. The paper offers institutional recommendations for facilitating an IWRM approach within NRCS, and concludes with a consideration of the utility of IWRM design principles and the IAD framework for analyzing water management institutions. / Graduation date: 2012

In this study, methodologies for modeling grey uncertainty in water resources systems are developed, specifically for the problems in two identified areas in water resources: waste load allocation in streams and floodplain planning. A water resources system is associated with some degree of uncertainty, due to randomness of hydrologic and hydraulic parameters, imprecision and subjectivity in management goals, inappropriateness in model selection, inexactness of different input parameters for inadequacy of data, etc. Uncertainty due to randomness of input parameters could be modeled by the probabilistic models, when probability distributions of the parameters may be estimated. Uncertainties due to imprecision in the management problem may be addressed by the fuzzy decision models. In addition, some parameters in any water resources problems need to be addressed as grey parameters, due to inadequate data for an accurate estimation but with known extreme bounds of the parameter values. Such inexactness or grey uncertainty in the model parameters can be addressed by the inexact or grey optimization models, representing the parameters as interval grey numbers. The research study presented in this thesis deals with the development of grey and fuzzy optimization models, and the combination of the two for water resources systems decision-making. Three grey fuzzy optimization models for waste load allocation, namely (i) Grey Fuzzy Waste Load Allocation Model (GFWLAM), (ii) two-phase GFWLAM and (iii) multiobjective GFWLAM, and a Grey Integer Programming (GIP) model for floodplain planning, are developed in this study. The Grey Fuzzy Waste Load Allocation Model (GFWLAM) for water quality management of river system addresses uncertainty in the membership functions for imprecisely stated management goals of the Pollution Control Agency (PCA) and dischargers. To address the imprecision in fixing the boundaries of membership functions (also known as membership parameters), the membership functions themselves are treated as imprecise in the model and the membership parameters are expressed as interval grey numbers. The conflict between the fuzzy goals of PCA and dischargers is modeled using the concept of fuzzy decision, but because of treating the membership parameters as interval grey numbers, in the present study, the notion of ‘fuzzy decision’ is extended to the notion of ‘grey fuzzy decision’. A terminology ‘grey fuzzy decision’ is used to represent the fuzzy decision resulting from the imprecise membership functions. The model provides flexibility for PCA and dischargers to specify their aspirations independently, as the membership parameters for membership functions are interval grey numbers in place of a deterministic real number. In the solution, optimal fractional removal levels of the pollutants are obtained in the form of interval grey numbers. This enhances the flexibility and applicability in decision-making, as the decision-maker gets a range of optimal solutions for fixing the final decision scheme considering technical and economic feasibility of the pollutant treatment levels. The methodology is demonstrated with the case studies of a hypothetical river system and the Tunga-Bhadra river system in Karnataka, India. Formulation of GFWLAM is based on the approach for solving fuzzy multiple objective optimization problem using max-min as the operator, which usually may not result in a unique solution. The two-phase GFWLAM captures all the alternative optimal solutions of the GFWLAM. The solution technique in the Phase 1 of two-phase GFWLAM is the same as that of GFWLAM. The Phase 2 maximizes upper bounds and minimizes lower bounds of decision variables, keeping the optimal value of goal fulfillment level same as obtained in the Phase 1. The two-phase GFWLAM gives the unique, widest, intervals of the optimal fractional removal levels of pollutant corresponding to the optimal value of goal fulfillment level. The solution increases the widths of interval-valued fractional removal levels of pollutants by capturing all the alternative optimal solutions and thus enhances the flexibility and applicability in decision-making. The model is applied to the case study of Tunga-Bhadra river system, which shows the existence of multiple solutions when the GFWLAM is applied to the same case study. The width of the interval of optimal fractional removal level plays an important role in the GFWLAM, as more width in the fractional removals implies a wider choice to the decision-makers and more applicability in decision-making. The multiobjective GFWLAM maximizes the width of the interval-valued fractional removal levels for providing a latitude in decision-making and minimizes the width of goal fulfillment level for reducing the system uncertainty. The multiobjective GFWLAM gives a new methodology to get a satisfactory deterministic equivalent of a grey fuzzy optimization problem, using the concept of acceptability index for a meaningful ranking between two partially or fully overlapping intervals. The resulting multiobjective optimization model is solved by fuzzy multiobjective optimization technique. The consistency of the solution is verified by solving the problem with fuzzy goal programming technique. The multiobjective GFWLAM avoids intermediate submodels unlike GFWLAM, so that the solution from a single deterministic equivalent of the GFWLAM adequately covers all possible situations. Although the solutions obtained from multiobjective GFWLAM provide more flexibility than those of the GFWLAM, its application is limited to grey fuzzy goals expressed by linear imprecise membership functions only, whereas GFWLAM has the capability to solve the model with any monotonic nonlinear imprecise membership functions also. The methodology is demonstrated with the case studies of a hypothetical river system and the Tunga-Bhadra river system in Karnataka, India. The Grey Integer Programming (GIP) model for floodplain planning is based on the floodplain planning model developed by Lund (2002), to identify an optimal mix of flood damage reduction options with probabilistic flood descriptions. The model demonstrates how the uncertainty of various input parameters in a floodplain planning problem can be modeled using interval grey numbers in the optimization model. The GIP model for floodplain planning does not replace a post-optimality analysis (e.g., sensitivity analysis, dual theory, parametric programming, etc.), but it provides additional information for interpretation of the optimal solutions. The results obtained from GIP model confirm that the GIP is a useful technique for interpretation of the solutions particularly when a number of potential feasible measures are available in a large scale floodplain planning problem. Though the present study does not directly compare the GIP technique with sensitivity analysis, the results indicate that the rigor and extent of post-optimality analyses may be reduced with the use of GIP for a large scale floodplain planning problem. Application of the GIP model is demonstrated with the hypothetical example as presented in Lund (2002).

From the Proceedings of the 1982 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 24,1982, Tempe, Arizona / A prototypical computer simulation model has been developed to aid watershed managers in estimating impacts of alternative land management practices on nutrient and heavy metal losses due to transported sediment on forested watersheds of the southwestern United States. The model, called SEDCON, allows users at remote locations with modest computer terminal equipment and commonly available data to obtain reliable estimates of nutrient and heavy metal concentrations in suspended sediment originating on uniformly-stocked, forested watersheds in the Southwest. SEDCON has been structured in an interactive mode to facilitate its use by persons not familiar with computer operations. Written in FORTRAN IV computer language, the model requires approximately 5000 words of core. SEDCON is operative on a DEC-10 computer at the University of Arizona.

No description available.

No description available.

In common with other natural systems, aquatic ecosystems provide a wealth of economically valuable services and long-term benefits to society. However, growing human populations, coupled with increased aspirations for improved quality of life, have lead to intense pressure on the world's finite freshwater resources. Frequently, particularly in developing countries, there are both perceived and genuine incompatibilities between ecological and societal needs for freshwater. Environmental Flow Assessment (EFA) is essentially a tool for water resources management and its ultimate goal should be the integration of ecological and societal systems. While other ecological components (i.e. biological and geomorphological) are equally important to EFA, this thesis investigates the role of the hydrological cycle and the hydrological regime in providing the ecosystem goods and services upon which society depends. Ecological and societal systems operate at different temporal, spatial and organisational scales and hydronomic zoning or sub-zoning is proposed as an appropriate water resources management technique for matching these different scales. A major component of this thesis is a review of the South African water resources management framework and, in particular, the role of the Reserve (comprising a basic human right to survival water as well as an ecological right of the aquatic resource to maintain ecological functioning) in facilitating ecologically sustainable water resources management. South African water resources management is in the early stages of water allocation reform and the Department of Water Affairs and Forestry has stated that "the water allocation process must allow for the sustainable use of water resources and must promote the efficient and non-wasteful use of water". Thus, new ways of approaching the compromise between ecological and societal needs for freshwater water are required. This thesis argues that this requires that the focus of freshwater ecosystems be extended beyond the aquatic resource, so that societal activities on the catchment are linked to the protection of instream flows. Streamflow variability plays a major role in structuring the habitat templates that sustain aquatic and riparian ecological functioning and has been associated with increased biodiversity. Biodiversity and societal well-being are interlinked. However, there is a need in EFA for knowledge of the most influential components of the streamflow regime in order that stakeholders may anticipate any change in ecosystem goods and services as a result of their disruption to the hydrological cycle. The identification of high information hydrological indicators for characterising highly variable streamflow regimes is useful to water resources management, particularly where thresholds of streamflow regime characteristics have ecological relevance. Several researchers have revisited the choice of hydrological indices in order to ascertain whether some indices explain more of the hydrological variability in different aspects of streamflow regimes than others. However, most of the research relating to hydrological indices has focused primarily on regions with temperate climates. In this thesis multivariate analysis is applied to a relatively large dataset of readily computed ecologically relevant hydrological indices (including the Indicators of Hydrological Alteration and the South African Desktop Reserve Model indices) extracted from long-term records of daily flows at 83 sites across South Africa. Principal Component Analysis is applied in order to highlight general patterns of intercorrelation, or redundancy, among the indices and to identify a minimum subset of hydrological indices which explain the majority of the variation among the indices of different components of the streamflow regimes found in South Africa. The results indicate the value of including several of the IHA indices in EFAs for South African rivers. Statistical analysis is meaningful only when calculated for a sufficiently long hydrological record, and in this thesis the length of record necessary to obtain consistent hydrological indices, with minimal influence of climatic variation, is investigated. The results provide a guide to the length of record required for analysis of the high information hydrological indices representing the main components of the streamflow regime, for different streamflow types. An ecosystem-based approach which recognises the hydrological connectivity of the catchment landscape in linking aquatic and terrestrial systems is proposed as a framework for ecologically sustainable water resources management. While this framework is intended to be generic, its potential for application in the South African Water Allocation Reform is illustrated with a case study for the Mkomazi Catchment in KwaZulu-Natal. Hydronomic sub-zoning, based on the way in which societal activities disrupt the natural hydrological processes, both off-stream and instream, is applied to assess the incompatibilities between societal and ecological freshwater needs. Reference hydrological, or pre-development, conditions in the Mkomazi Catchment are simulated using the ACRU agrohydrological model. Management targets, based on the statistical analysis of pre-development streamflow regimes, are defined to assess the degree of hydrological alteration in the high information hydrological indices of the Mkomazi Catchment as a result of different societal activities. Hydrological alteration from predevelopment conditions is assessed using the Range of Variability Approach. The results indicate that the proposed framework is useful to the formulation of stakeholder-based catchment management plans. Applying hydrological records (either observed or simulated) as an ecological resource is highly appropriate for assessing the variability that ecosystems need to maintain the biodiversity, ecological functioning and resilience that people and society desire. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Over the last decades, fast growing population along with urban and agricultural sprawl has drastically increased the pressure on water resources of the Federal District (DF), Brazil. Various socio-environmental problems, such as soil erosion, non-point source pollution, reservoir silting, and conflicts among water users evoked the need for more efficient and sustainable ways to use land and water. Due to the complexity of processes relevant at the scale of river basins, a prior analysis of impacts of certain land use and/or land management changes is only feasible by means of modeling. The Soil and Water Assessment Tool (SWAT) has been proven to be useful in this context, across the globe and for different environmental conditions. In this thesis, the SWAT model is utilized to evaluate the impact of Best Management Practices (BMPs) on catchment hydrology and sediment transport. However, model applications in tropical regions, such as the DF, are hampered by severe challenges, (i) the lack of input and control data in an adequate temporal and spatial resolution and (ii) model structural failures in representing processes under tropical conditions. The present (cumulative) thesis addresses these challenges in model simulations for two contrasting watersheds, which both are important sources of the DF’s drinking water supply, i.e. (i) the agriculture-dominated Pipiripau river basin where conflicting demands put immense pressure on the available water resources and (ii) the Santa Maria / Torto river basin, which is to large parts protected as national park and, thus, covered by native vegetation of the Cerrado biome. Perhaps one of the most challenging issues facing watershed modelers in tropical regions is the fact that rain gauge networks can usually not reflect the high spatio-temporal variability of mostly convective precipitation patterns. Therefore, an ensemble of different reasonable input precipitation data-sets was used to examine the uncertainty in parameterization and model output. Acceptable streamflow and sediment load predictions could be achieved for each input data-set. However, the best-fit parameter values varied widely across the ensemble. Due to its enhanced consideration of parameter uncertainty, this ensemble approach provides more robust predictions and hence is reasonable to be used also for scenario simulations. BMP scenarios for the Pipiripau River Basin revealed that erosion control constructions, such as terraces and small retention basins along roads (Barraginhas) are promising measures to reduce sediment loads (up to 40%) while maintaining streamflow. Tests for a multi-diverse crop rotation system, in contrast, showed a high vulnerability of the hydrologic system against any increase in irrigation. Considering the BMP implementation costs, it was possible to estimate cost-abatement curves, which can provide useful information for watershed managers, especially when BMPs are supported by Payments for Environmental Services as it is the case in the study area due to the program Produtor de Água. While for agricultural areas the model has proven to generate plausible results, the plant growth module of SWAT was found to be not suitable for simulating perennial tropical vegetation, such as Cerrado (savanna) or forest, which can also play a crucial role in river basin management. For temperate regions SWAT uses dormancy to terminate growing seasons of trees and perennials. However, there is no mechanism considered to reflect seasonality in the tropics, i.e. the phenological change between wet and dry season. Therefore, a soil moisture based approach was implemented into the plant growth module to trigger new growing cycles in the transition period from dry to wet season. The adapted model was successfully tested against LAI and ET time series derived from remote sensing products (MODIS). Since the proposed changes are process-based but also allow flexible model settings, the modified plant growth module can be seen as a fundamental improvement useful for future model application in the tropics. The present thesis shows insights into the workflow of a watershed model application in the semi-humid tropics – from input data processing and model setup over source code adaptation, model calibration and uncertainty analysis to its use for running scenarios. It depicts region-specific challenges but also provides practical solutions. Hence, this work might be seen as one further step toward robust and process-based model predictions to assist land and water resources management. / Starkes Bevölkerungswachstum, ungeplante Suburbanisierung und Landnutzungsänderungen (z.B. Intensivierung in der Landwirtschaft) verstärkten innerhalb der letzten Jahrzehnte zunehmend den Druck auf die Wasserressourcen des Bundesdistrikts Brasilien (zentralbrasilianisches Hochland), in dessen Mitte die junge Hauptstadt Brasília liegt. Damit verbundene negative Umweltauswirkungen, wie Bodenerosion, Stoff- und Sedimenteinträge in Fließgewässer und Talsperren sowie Konflikte zwischen den Wassernutzern erfordern daher dringend effektive und nachhaltige Lösungen im Land- und Wasserressourcen-management. Der Einfluss von möglichen zukünftigen Landnutzungs- und Bewirtschaftungsänderungen auf Wasserverfügbarkeit und -qualität hängt vom jeweiligen, oftmals sehr komplexen, landschaftsökologischen Prozessgefüge ab und kann nur mithilfe von prozessbasierten Simulationsmodellen quantitativ auf der Ebene von Einzugsgebieten abgeschätzt werden. Das “Soil and Water Assessment Tool” (SWAT) ist ein solches Modell. Es findet weltweite Anwendung für verschiedene Umweltbedingungen in Einzugsgebieten der Meso- bis Makroskala, um Landnutzungseffekte auf den Wasserhaushalt und den Transport von Nährstoffen, Pestiziden und Sedimenten zu prognostizieren. Seine Anwendung in tropischen Regionen, wie etwa in Zentralbrasilien, ist jedoch mit erheblichen Herausforderungen verbunden. Das betrifft sowohl die Verfügbarkeit von Eingangs- und Referenzdaten in ausreichender raum-zeitlicher Auflösung, als auch modellstrukturelle Unzulänglichkeiten bei der Prozessabbildung. Die vorliegende kumulative Dissertation zeigt dies anhand von Modellanwendungen für zwei unterschiedliche wasserwirtschaftlich relevante Einzugsgebiete (EZG): Das landwirtschaftlich intensiv genutzte EZG des Rio Pipiripau mit aktuell besonders konfliktträchtiger Wassernutzung, und das Santa Maria/Torto-EZG, welches - geschützt als Nationalpark - durch größtenteils natürliche Vegetationsformationen der brasilianischen Savanne (Cerrado) gekennzeichnet ist. Eine der größten Herausforderungen für die Einzugsgebietsmodellierung in tropischen Regionen liegt in der Abschätzung des Gebietsniederschlages, da vorhandene Messstationsdichten oft nicht ausreichen, um die hohe räumliche und zeitliche Variabilität der meist konvektiven Niederschläge zu erfassen. Mithilfe eines Ensembles verschiedener, plausibel generierter Niederschlagsreihen ist der Einfluss von Niederschlagsdaten-Unsicherheit auf die Modellparametrisierung und -vorhersage explizit berücksichtigt und untersucht worden. Zufriedenstellende Abfluss- und Sedimentfrachtsimulationen waren mit jeder der als Modelinput verwendeten Niederschlagsreihen möglich, jedoch nur bei entsprechender, z.T. stark voneinander abweichender Einstellung der Kalibrierungsparameter. Da diese umfassendere Betrachtung von Parameterunsicherheit zu robusteren Modellvorhersagen führt, wurde der Ensemble-Ansatz auch in der Simulation von Bewirtschaftungsszenarien, dem eigentlichen Modellzweck, verwendet. Die Szenariosimulationen zeigten, dass Maßnahmen zur Erosionsvermeidung (Terrassierung) und zum Sedimentrückhalt (kleine Sedimentrückhaltebecken entlang von Straßen - Barraginhas) die Sedimentfracht des Rio Pipiripau durchschnittlich um bis zu 40% reduzieren können, ohne dabei die Wasserverfügbarkeit zu beeinträchtigen. Modellszenarien mit einer vielgliedrigen Fruchtfolge auf großer Fläche verdeutlichten dagegen die hohe Vulnerabilität des Niedrigwasserabflusses in der Trockenzeit gegenüber jedweder Erhöhung der Bewässerungsmenge. Auf Grundlage von Kostenschätzungen für einzelne Maßnahmen konnten Kostenkurven zur Verringerung der Sedimentfracht und damit nützliche Informationen für das Wasserressourcen-Management abgeleitet werden, insbesondere weil eine Auswahl solcher Agrar-Umweltmaßnahmen im Pipiripau-EZG durch das Programm Produtor de Água finanziell gefördert werden sollen. Während das Modell in landwirtschaftlich genutzten Gebieten plausible Ergebnisse produzierte, wurden erhebliche Schwachstellen in der Simulation ausdauernder Vegetation (z.B. Cerrado) identifiziert. Zur Unterbrechung jährlicher Vegetationszyklen verwendet SWAT eine tageslängenabhängige Dormanzperiode. Diese ist zwar zweckmäßig zur Abbildung der Vegetationsdynamik in den gemäßigten Breiten, steuert aber nicht tropische Vegetationszyklen. Um den Wechsel zwischen Trocken- und Regenzeit in der pflanzenphänologischen Simulation in SWAT abzubilden, wurde daher im Rahmen dieser Arbeit das Pflanzenwachstumsmodul modifiziert, und zwar unter anderem durch Einbeziehung der simulierten Bodenfeuchte zur Unterbrechung der Wachstumszyklen. Das angepasste Modul wurde erfolgreich anhand von Fernerkundungsdaten (MODIS) zum zeitlichen Verlauf von Blattflächenindex und Evapotranspiration getestet. Es ist prozessbasiert und erlaubt flexible Einstellungen, so dass es als grundlegende Modellverbesserung auch für andere SWAT-Anwender von großem Nutzen sein kann. Die vorliegende Dissertation bringt neue Einsichten in verschiedene wichtige Aspekte der integrierten Modellierung tropischer Einzugsgebiete, von der Eingangsdatenaufbereitung über Quellcode-Anpassung, Modellkalibrierung und Unsicherheitsanalyse bis hin zu Szenariosimulationen. Sie veranschaulicht regionsspezifische Herausforderungen, liefert gleichzeitig aber auch praktikable Lösungen und damit einen wichtigen Beitrag für robustere prozessbasierte Modellanwendungen als Entscheidungsunterstützung im Bereich Land- und Wasserressourcenmanagement.

Wasserwirtschaftliche Speichersysteme sind unverzichtbar, um weltweit die Trinkwasserversorgung, Nahrungsmittelproduktion und Energieversorgung sicherzustellen. Die multikriterielle simulationsbasierte Optimierung (MK-SBO) ist eine leistungsfähige Methodik, um für Mehrzweck-Talsperrenverbundsysteme (MZ-TVS) eine Pareto-optimale Menge an Kompromisslösungen zwischen konträren Zielen bereitzustellen. Der rechentechnische Aufwand steigt jedoch linear mit der Länge des Simulationszeitraums der Talsperrenbewirtschaftung an. Folglich begrenzen sich MK-SBO-Studien bisher auf Simulationszeiträume von wenigen Jahrzehnten. Diese Zeiträume sind i.d.R. unzureichend, um Unsicherheiten, die aus der stochastischen Natur der Zuflüsse resultieren, adäquat zu beschreiben. Bewirtschaftungsoptimierungen von MZ-TVS hinsichtlich ihrer Zuverlässigkeit, z.B. durch die Maximierung von Versorgungssicherheiten, können sich als wenig belastbar und ermittelte Steuerungsstrategien als wenig robust erweisen. Um diesen Herausforderungen zu begegnen, wird ein neues modulares Framework zur multikriteriellen simulationsbasierten Bewirtschaftungsoptimierung von MZ-TVS (Frams-BoT) entwickelt. Eine Informationserweiterung zu stochastischen Zuflussprozessen erfolgt über ein weiterentwickeltes Zeitreihenmodell mittels generierter Zeitreihen von mehreren Tausend Jahren Länge. Eine neue Methode zur Monte-Carlo-Rekombination von Zeitreihen ermöglicht dann die Nutzung dieser Informationen in der MK-SBO in wesentlich kürzeren Simulationszeiträumen. Weitere Rechenzeit wird durch Parallelisierung und eine fortgeschrittene Kodierung von Entscheidungsvariablen eingespart. Die Simulation von Zuflussdargeboten für multikriterielle Klimafolgenanalysen erfolgt durch ein prozessorientiertes Wasserhaushaltsmodell. Level-Diagramme (Blasco et al., 2008) unterstützten den komplexen Prozess der Entscheidungsfindung. Die Wirksamkeit und Flexibilität des Frameworks wurden in zwei Fallstudien gezeigt. In einer ersten Fallstudie konnten in einer Klimafolgenanalyse Versorgungssicherheiten von über 99% als ein Ziel eines multikriteriellen Optimierungsproblems maximiert werden, um die Verlässlichkeit der Bewirtschaftung eines MZ-TVS in Sachsen (Deutschland) zu steigern. Eine zweite Fallstudie befasste sich mit der Maximierung der Leistungsfähigkeit eines MZ-TVS in Äthiopien unter verschiedenen Problemformulierungen. In beiden Fallstudien erwiesen sich die erzielten Pareto-Fronten und Steuerungsstrategien gegenüber 10 000-jährigen Zeiträumen als robust. Die benötigten Rechenzeiten der MK-SBO ließen sich durch das Framework massiv senken. / Water resources systems are worldwide essential for a secure supply of potable water, food and energy production. Simulation-based multi-objective optimization (SB-MOO) is a powerful method to provide a set of Pareto-optimal compromise solutions between various contrary goals of multi-purpose multi-reservoir systems (MP-MRS). However, the computational costs increases with the length of the time period in which the reservoir management is simulated. Consequently, MK-SBO studies are currently restricted to simulation periods of several decades. These time periods are normally insufficient to describe the stochastic nature of the inflows and the consequent hydrological uncertainties. Therefore, an optimization of the reliability of management of MP-MRS, e.g. through the maximization of the security of supply, may not be resilient. Obtained management strategies may not prove robust. To address these challenges, a new modular framework for simulation-based multiobjective optimization of the reservoir management of multi-purpose multi-reservoir systems (Frams-BoT) is developed. A refined time series model provides time series of several thousand years to extend the available information about the stochastic inflow processes. Then, a new Monte-Carlo recombination method allows for the exploitation of the extended information in the SB-MOO on significantly shorter time periods. Further computational time is saved by parallelization and an advanced coding of decision variables. A processoriented water balance model is used to simulate inflows for multi-objective climate impact analysis. Level-Diagrams [Blasco et al., 2008] are used to support the complex process of decision-making. The effectiveness and flexibility of the framework is presented in two case studies. In the first case study about a MP-MRS in Germany, high securities of supply over 99% where maximized as part of a multi-objective optimization problem in order to improve the reliability of the reservoir management. A second case study addressed the maximization of the performance of a MP-MRS in Ethiopia under different formulations of the optimization problem. In both case studies, the obtained Pareto-Fronts and management strategies proved robust compared to 10 000 year time periods. The required computational times of the SB-MOO could be reduced considerably.