This work focuses on the evaluation of dependence between the spring discharge fluctuations and water temperature, both during the year and extreme rainfall-runoff events, on spring equipped with a V-notch weir with a continuous monitoring of spring water temperature and water level above the weir. Data were gathered on descending fissure spring of Tocnicky stream, located in the southwestern part of the Planicky ridge natural park in Klatovsko region. More data and stand characteristics (air temperature, soil temperature profile, soil moisture) were measured for better evaluation of the dependence, both at the spring location and in the infiltration area on the western slope of local highest peak Rovná. The formation of runoff on the slope above measured spring is likely to be subject to a combination of shallow circulation with a component of preferential flow during extreme rainfall-runoff events and deeper circulation, which is not yet well known and understood.

Made available in DSpace on 2014-08-27T14:36:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-09-02Bitstream added on 2014-08-27T15:57:07Z : No. of bitstreams: 1 000680532.pdf: 782922 bytes, checksum: 588fc6a045d63f818ce2cecdd6e81492 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Este estudo avaliou a metodologia dos isótopos estáveis de carbono como um método alternativo e mais apurado para determinar o tempo de trânsito gastrointestinal (TTG) em juvenis de pacu (Piaractus mesopotamicus), em comparação ao método convencional com a adição de marcadores de contraste na dieta. Foram utilizados 320 juvenis estocados em 32 tanques, que receberam duas dietas, uma baseada em ingredientes do ciclo fotossintético C3 e outra baseada em ingredientes de origem C4, ambas contendo marcador inerte óxido de titânio (para tornar as fezes esbranquiçadas) e cultivados em duas temperaturas de água, 25 e 29 ºC. Após 40 dias, as dietas foram trocadas: os animais que recebiam a dieta C3 passaram a receber a dieta C4 (C3/C4) e vice-versa (C4/C3). As novas dietas continham marcador inerte óxido de crômio, para determinar o TTG através das duas metodologias: a convencional que utiliza marcadores de contraste e outra, sugerida neste estudo, por meio dos isótopos estáveis de carbono. As fezes foram coletadas por extrusão manual durante um período de 30 horas após a troca das dietas. Na metodologia dos marcadores inertes, as fezes receberam notas de 0; 0,25; 0,50; 0,75 e 1,00 de acordo com a intensidade da mudança de coloração de branco para verde escuro. Na metodologia dos isótopos estáveis, as fezes foram analisadas para determinação da mudança da razão isotópica de carbono-13. O delineamento experimental utilizado foi inteiramente casualizado com quatro tratamentos e oito réplicas. Os dados obtidos de desempenho produtivo foram submetidos à análise de variância (ANOVA), seguida pelo teste de Tukey (? = 0,05), quando detectadas diferenças significativas. Os dados de TTG obtidos em ambas as metodologias avaliadas foram analisados... (Resumo completo, clicar acesso eletrônico abaixo) / This study evaluated the stable carbon isotopes as an alternative and more accurate methodology to determine the gastrointestinal transit time (GTT) in pacu (Piaractus mesopotamicus) compared with the conventional method with addition contrast markers in the diet. 320 juveniles were equally distributed in 32 tanks. These tanks were divided in two feedings groups containing titanium oxide as inert marker in their diets (to induce white feces). One group was fed with diets based on 03 photosynthetic cycle plants, while the other group was fed with diets based on 04 plants. Both feeding treatments were subdivided in two water temperatures cultures, 25 and 29 °C. After 40 days we changed the diets: animals that had been fed with 03 diets were then fed with 04 diets (03/04) and vice versa (04/03). The new diets had chromium oxide as inert marker to determine the GTT through both methodologies: the conventional one which uses contrast markers, and other, suggested in this study, using stable carbon isotopes. Feces were collected by manual extrusion during 30 hours period after diet change. For the inert markers methodology the feces were graded in 0, 0.25, 0.50, 0.75 and 1.00 accordingly to the intensity of the color pattern that ranges from white to dark green. For the stable isotopes methodology the feces were analyzed to determine the change in the isotopic ratio of carbon-13. We conducted a completely randomized experimental design with four treatments and eight replicates. Data obtained from performance were subjected to analysis of variance (ANOVA) followed by Tukey test (a = 0.05), when significant differences were detected. GTT data, of both methodologies, were analyzed accordingly to the Boltzmann sigmoidal regression model. The average of water temperatures... (Complete abstract click electronic access below)

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-01T14:09:27Z No. of bitstreams: 1 flavianedefatimacandidadesouza.pdf: 2746511 bytes, checksum: fd1e6e022a94ac14636201a0ef8c3562 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T12:59:23Z (GMT) No. of bitstreams: 1 flavianedefatimacandidadesouza.pdf: 2746511 bytes, checksum: fd1e6e022a94ac14636201a0ef8c3562 (MD5) / Made available in DSpace on 2016-07-02T12:59:23Z (GMT). No. of bitstreams: 1 flavianedefatimacandidadesouza.pdf: 2746511 bytes, checksum: fd1e6e022a94ac14636201a0ef8c3562 (MD5) Previous issue date: 2012-02-03 / Os mananciais de abastecimento público localizados em área urbana vêm sofrendo forte pressão do setor imobiliário que por vezes não poupa o entorno dos mananciais frente a expansão da mancha urbana. Os estudos desses ambientes considerando o sistema físico bacia hidrográfica são importantes para o conhecimento das alterações ocorridas ao longo do processo de urbanização. Neste contexto, este trabalho teve como objetivo principal proporcionar uma visão sistêmica do reservatório de São Pedro, Juiz de Fora/MG, com base na avaliação do seu comportamento térmico através da modelagem, além de avaliar seu estado trófico. Foi utilizado o modelo IPH-ECO para simular a temperatura superficial da água com base em elementos climatológicos e condições de contorno (vazões de entrada e saída do reservatório). A modelagem ocorreu de Julho de 2010 a Junho de 2011, onde os parâmetros temperatura da água e oxigênio dissolvido foram monitorados. Os ensaios de fósforo total foram realizados visando a caracterização do grau de eutrofização deste reservatório através do cálculo do índice de estado trófico (IET). Os resultados mostraram uma baixa fertilização do reservatório, com predominância do enquadramento oligotrófico segundo a classificação de Carlson modificada por Toledo. A simulação da temperatura da água se mostrou de forma eficiente com representatividade acima de 90 %. As temperaturas se comportaram de forma satisfatória no processo da modelagem, considerando as vazões dos tributários. As simulações de temperatura da água, em média pelos três pontos de saída selecionados no modelo, ficaram em torno de 21,95 ºC e as temperaturas observadas, também em média pelos três pontos, ficaram em torno de 22, 21 °C. Portanto a representatividade do modelo se mostrou eficiente para o reservatório de São Pedro. A contribuição dos afluentes se mostrou muito importante para as simulações hidrodinâmicas, pois a variação das vazões limita ou regulariza as temperaturas deste reservatório. / The public water supply sources located in an urban area has come under heavy pressure from the real estate industry that sometimes does not spare the surroundings of springs forward the expansion of urban sprawl. Studies of these environments considering the physical system watershed are important to understanding the changes in the process of urbanization. In this context, this study aimed to provide a systemic view of the reservoir of São Pedro, Juiz de Fora / MG, based on evaluation of their thermal behavior through modeling, assessing its trophic state. We used the IPH-ECO model to simulate the surface temperature of the water on the basis of climatological and boundary conditions (flow rates in and out of the reservoir). The modeling was July 2010 to June 2011, where the parameters water temperature and dissolved oxygen were monitored. The total phosphorus tests were conducted to characterize the degree of eutrophication of the reservoir by calculating the trophic state index (IET). The results showed a low fertilization of the reservoir, with a predominance of oligotrophic environment according to the classification modified by Carlson Toledo. The simulation of the temperature of the water proved so efficient with over 90% representation. Temperatures behaved satisfactorily in the process of modeling, considering the flow of the tributaries. The simulations of water temperature on average by three points selected in the model output, were around 21.95 ° C and the observed temperatures, again on average by three points, were around 22, 21 ° C. Therefore, the representativeness of the model is efficient for the shell of São Pedro. The contribution of the tributaries was very important for the hydrodynamic simulations, as the variation of flow limits or regulates the temperature of the reservoir.

No description available.

Limnologists and stream ecologists acknowledge the fundamental importance of temperature for regulating many ecological, biological, chemical, and physical processes. I investigated how water temperatures were affected by hydrologic linkages between streams and lakes at various positions along surface water networks throughout several headwater basins in the Sawtooth and White Cloud Mountains of Idaho (USA). Temperatures of streams and lakes were measured for up to 27 months in seven 6 – 41 km2 watersheds, with a range of lake influence. When they were ice-free, warming in lakes resulted in dramatically warmer temperatures at lake outflows compared to inflow streams (midsummer average 6.4°C warming, but as much as 12.5°C). Temperatures cooled as water traveled downstream from lakes, as rapidly as 9°C km-1. Longitudinal stream cooling was usually not strong enough, however, to reduce temperatures to baseline conditions. In early spring, lakes had the opposite effect on streams, as they released water from beneath the ice at near 0°C. Early spring stream water warmed as it flowed downstream from lakes, influenced by additional groundwater inflows. In addition to lakes, other watershed characteristics influenced temperatures, though effects differed seasonally. Multiple regression analyses indicated that lake size, distance from nearest upstream lake, and stream shading were most important in explaining stream temperatures, but the relative importance of each variable changed seasonally.

Thesis (M.Sc. (Aquaculture)) -- University of Limpopo, 2022 / The aim of this study was to provide baseline limnology data that can be used in the management of small dams, Molepo Dam and Hout River Dam. Physico-chemical parameters were assessed to determine the water quality and the effect of water level fluctuations on water quality. Water temperature, pH, dissolved oxygen, turbidity, electrical conductivity, nitrate, total phosphorus, total nitrogen and chlorophyll-a were assessed during the dry season (May-Oct) and wet season (Nov-Apr). Physico chemical parameters showed seasonal variations with the exception of pH. The mean total phosphorus (1.06 and 0.98 mg/L), total nitrogen (1.27 and 1.56 mg/L) and chlorophyll-a (2.97 and 3.32 µg/L) were higher in the dry season than wet season in Molepo Dam and Hout River Dam respectively. Water level fluctuations had a significant effect on total nitrogen, total phosphorus and turbidity in Molepo Dam and total nitrogen in Hout River Dam. Plankton were used as indicators of water quality. Phytoplankton and zooplankton were sampled using nets of 71 µm and 132 µm mesh respectively and identified to genus and species at both Molepo Dam and Hout River Dam. Individual species, number per litre for phytoplankton groups that contributed significantly in terms of abundance were Microcystis aeruginosa and Oscillatoria sp. in both Molepo Dam and Hout River Dam during the dry season months. The Shannon-Wiener diversity index was high during the wet season in these small dams. The abundance of Cyanophyta was greatest during the dry season followed by Desmids in Molepo Dam and Hout River Dam. During the wet season, Bacillariophyta were not recorded for Hout River Dam. The highest composition for Chlorophyta (15.4%) in Molepo Dam was recorded during the wet season months. Phytoplankton abundance was highest in Molepo Dam as compared to Hout River Dam throughout the sampling period. Zooplankton was dominated by Cladocerans (Bosmina longirostris) in both small dams. This study showed that plankton can be used as indicators of water quality. Zooplankton communities were dominated by Bosmina longirostris which was present throughout the sampling period possibly indicating clear water in Molepo Dam and Hout River Dam. Copepoda were sub-dominant phyla mainly represented by Cycloid sp. which are also indicators of clean water. The study determined the abundance and composition of fish species and growth parameters of the most abundant fish species (Oreochromis mossambicus) in the two small dams. Scales were successfully used for the age determination of O. mossambicus. The rings on the scales were validated as being true annuli by marginal increment analysis which indicated that the distance between the last annuli and the scale edge was shortest in the wet season months in Molepo Dam and Hout River Dam. This is the time in which annulus formed. Annulus formation of O. mossambicus at these small dams coincided with the onset of increased water temperature and rainfall (increased water levels and increased water inflow into the dams) in this region. Furthermore, the growth performance index (ϕ) of male O. mossambicus was higher than that of female O. mossambicus in both Molepo Dam and Hout River Dam. The study provides the first record of limnology baseline data of Molepo Dam and Hout River Dam / National Research Foundation (NRF) and Department of Agriculture, Forestry and Fisheries (DAFF)

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There have been growing concerns over the decline of healthy river ecosystems and the severe consequences this decline could have on biodiversity, ecosystem services, and human well-being. These concerns have led to increased efforts in river restoration around the globe, which aim to improve the ecological health and functioning of rivers. The restoration is usually done by implementing strategies such as hydromorphological adaptation and flow management. These measures, nevertheless, do not guarantee the recovery of river ecosystems. This is because there are multiple factors contributing to the success of restoration projects, which can vary depending on the specific characteristics of each river system. Habitat modeling, one of the most widely used ecological quality assessment tools for rivers, has been applied in the evaluation of restoration projects. An aquatic ecosystem is complex, and its dynamic nature requires a comprehensive understanding of the interconnections between biotic and abiotic components. These components also have a high degree of spatial and temporal variability. Therefore, it is crucial that approaches and modeling techniques be tailored to capture this dynamic. In the assessment of river restoration, for instance, habitat modeling needs to account for the changes in flow patterns, sediment transport, water quality, and habitat availability/quality for the key indicator species that result from the restoration efforts. This study addresses the need for developing an integrated approach to habitat modeling, particularly for macrozoobenthos, an important indicator of river health that plays a crucial role in the functioning of aquatic ecosystems. The primary research objective is to improve the existing modeling framework (TRiMM) by focusing on three key aspects: 1) expanding the prediction factors of physical habitat that influence habitat suitability for macrozoobenthos; 2) integrating fuzzy algorithms in the suitability assignment process; 3) incorporating species' (re-)colonization capacity and habitat temporal variability into habitat connectivity assessment. The model adopts the fuzzy logic method in the habitat module to account for the interactions between various factors described in the habitat template (Poff & Ward, 1990). Moreover, the model considers both spatial and temporal changes in habitat parameters by running a transient simulation over a specific time period relevant to the life cycle requirements of the target species. This allows for a more accurate representation of the dynamic nature of river habitats and provides valuable insights into how they may change over time. Additionally, the model incorporates species' (re-)colonization potentials into habitat connectivity analysis by considering their dispersal capabilities. This helps in understanding how changes in habitat parameters can affect the overall connectivity of river habitats, which is crucial for assessing the resilience and sustainability of the systems. The proposed transient habitat modeling (TRiMM 2.0) is applied to two case studies of low-order rivers in Germany. The first case study focuses on a river that has been restored after a period of degradation. The habitat model was tested with sampling data, and the results reveal that the model improved when additional variables related to habitat were included. The second case study was a simulation of habitat suitability and connectivity in a hypothetical river reach. Hydraulic and morphological factors (water depth, velocity, temperature, and sediment) are simulated over a period of four years using SRH-2D. The simulation results showed that hydraulic and morphological factors had a significant impact on sediment characteristics, which in turn influenced habitat suitability and connectivity. This study also highlights the importance of considering multiple variables and their interactions when assessing river habitats. Additionally, the use of transient modeling provides information about long-term changes in habitat quality and connectivity.:Abstract Kurzfassung Contents List of figures List of tables Nomencature Acknowledgement List of publications 1. General introduction 1.1. Research motivation 1.2. Statement of research objectives 1.3. Structure of the dissertation 2. Macrozoobenthos and stream’s ecology 2.1. Macrozoobenthos and their habitat 2.2. Factors influencing the distribution of macrozoobenthos 2.2.1. Food sources 2.2.2. Water quality 2.2.3. Physical habitat 2.2.4. Colonization process 2.2.5. Presence of other species 2.3. Spatial scale and temporal variability 2.4. Conclusion 3. State of the art in river habitat modeling 3.1. Habitat modeling and river ecology assessment 3.2. Habitat modeling principles 3.2.1. Habitat suitability curves method 3.2.2. Fuzzy logic method 3.2.3. Generalized additive models 3.3. Existing benthos habitat modeling 3.3.1. PHABSIM 3.3.2. RHYHABSIM 3.3.3. BITHABSIM 3.3.4. CASiMiR 3.3.5. HABFUZZ 3.4. TRiMM and further development 3.5. Conclusion 4. Basis for the modeling concept and methodological framework 4.1. Physical habitat template 4.1.1. Streamflow regime 4.1.2. Substrate regime 4.1.3. Thermal regime 4.2. Habitat connectivity 4.3. Species colonization and habitat connectivity 4.4. Analysis scales 4.5. Conclusion 5. Transient river habitat modeling for macrozoobenthos – TRiMM 2.0 5.1. Habitat model description 5.2. Input data preparation 5.2.1. Field survey 5.2.2. Hydro-morphodynamic models 5.3. Habitat suitability calculation 5.4. Patch-building and patch dynamics analysis 5.5. Habitat connectivity calculation 5.6. Conclusion 6. Model applications 6.1. Case study 1: Simulation of habitat suitability for macrozoobenthos in a small restored stream (Saxony, Germany) Abstract 6.1.1. Introduction 6.1.2. Material and Method 6.1.3. Results 6.1.4. Discussion 6.1.5. Conclusion 6.2. Case study 2: Application of TRiMM 2.0 to simulate benthic habitat quality in a hypothetical reach of Zschopau river 6.2.1. Introduction 6.2.2. Methodology 6.2.3. Results 6.2.4. Discussion 6.2.5. Conclusion 7. Summary and future outlook 8. References

Water temperatures are a fundamental water quality component, and a key abiotic determinant of fish distribution patterns in rivers. A river 's thermal regime is the product of a multitude of thermal drivers and buffers interacting at different temporal and spatial scales, including, inter alia, air temperatures, flow volumes (including groundwater flows and lateral inputs from tributaries), channel geomorphology and riparian vegetation. "Healthy" river systems are self-sustaining, with adequate thermal variability to maintain biotic diversity. Temporal variability of flow volumes and water temperatures, and how these change along the longitudinal axis of a river, contribute towards a rivers "signature". Rivers that have had their signatures altered through anthropogenic impacts may no longer be sustainable, and require varying levels of management. Successful river management should include a quantification of these signatures , a definition of the "desired" state which management aims to achieve, associated "thresholds" of change or concern, and monitoring programmes. Such an approach requires flexibility and adaptability, as well as appropriate tools being available to natural resource managers. Indices, the utility of which are enhanced when included in predicative modelling systems, are a common means of assessing system variability and change. The degree of confidence placed in such tools depends on the level of fundamental science, and the degree of system understanding, underpinning them. This research contributes to the understanding of the ecological significance . of water temperatures in variable semi-arid river systems, using the Sabie River (Mpumalanga, South Africa) as a case study, and indices derived from biological indicators (Chiloglanis , Pisces: Mochokidae) to quantify the effects of cumulative changes in heat units against a hypothesised critical water temperature threshold. Hourly water temperatures for 20002002 collected at nine sites in the main rivers of the Sabie catchment, together with biannual surveys of relative abundances and community patterns of fish collected using standard electrofishing techniques, were used to provide the basis for a modelling system which aims to provide river managers with a tool for quantifying changes to the thermal regime of the Sabie River. This modelling system consisted of a suite of pragmatic models, including multiple linear regression models for simulating daily maximum water temperatures, and simple cause-and-effect relationships between biological indices (change In condition factor and change in the ratio of relative abundances of two species of Chiloglanis) and annual metrics of time-of-exposure to heat stress. It was concluded that changes in the thermal regimes of the rivers in the Sabie catchment are likely to lead to changes in fish distribution patterns, and a decline in river health. Inherent system variability suggests that management decisions will be made in the face considerable uncertainty. Indirect management of water temperatures may be possible through maintenance of flow volumes and flow variability. However, the most appropriate management approach for maintaining fish diversity within these rivers is to ensure that obstacles to fish migration are minimized, to maximise the ability of river biota to respond to thermal changes, by accessing suitable alternative habitats or refugia. Future research should focus on extending the time series of water temperatures from such river systems, and further understanding the drivers and buffers contributing to the thermal regimes of variable semi-arid river systems in South Africa. Additional testing of the validity of the hypothesized relationships between abiotic processes underpinning biotic patterns should be undertaken. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.

In many numerical weather prediction models, the presence of lakes is simulated crudely, with their effect being neglected in the resulting simulations. However, it has been shown how lakes effect not only their surrounding climate directly, but have an effect to the overall weather evolution and ecosystem. It is therefore vital to improve existing models to take lakes into account, by coupling with smaller models specificaly compiled for a reas with lakes. There have been several sophisticated models to parameterizelakes in a geographical area, which are, on the other hand, computationally expensive and time consuming. A model built specifically on simple physical assumptions, named FLake, aims to provide a solution that is not heavy computationally, but is accurate enough and contains all the necessary physics surrounding the heat budget and temperature of a given lake. For this project, FLake was tried on a lake close to Uppsala, named Erken, where the validity of the model was tested against data archives from Erken Laboratory’s measurement tower. The resulting simulations were very promising regarding the water temperatures, as well as giving out acceptable results for the surface heat fluxes above the lake and the duration of the ice period, as it was modeled by FLake and compared with ice data archives.