One of the major programs to abate the deterioration of water quality in the Lake Okeechobee watershed was the addition of detention-retention facilities. The microbial biochemical potential of two different detention-retention marshes in the Kissimmee River Valley were examined to determine their effectiveness to improve water quality. The kinetics of decomposition and nutrient mineralization and assimilation, as mediated by microorganisms, and the enumeration of microorganisms capable of utilizing various substrates were studied. Various communities within each marsh were studied during a 2-year period. The decomposition rates of 3 plant substrates were determined. Chitin was used as a standard for organic decomposition. Chitin had significantly higher (p< 0.05) rates of decomposition than the plant material in all sites at both marshes. Chitin decomposition rates were significantly different (p< 0.05) between sites. Significant differences (p< 0.05) in rates of decomposition were also found between the 3 plant substrates. the difference in decomposition rates for the 3 plant substrates existed within sites, as well as between sites. The number of microorganisms and the mineralization and assimilation rates were significantly different (p< 0.05) between the detention-retention marshes. Significant differences (p< 0.05) in numbers of microorganisms and rates were also found between sites within each marsh. The variation in detrital processing demonstrated that site-specific dynamics occurred in the detention-retention marshes. Higher decomposition rates were associated with sediment sites containing organic matter with either a continuous, shallow flow of water or alternate wet/dry periods. Decomposition rates were lowest at sites containing sandy sediments, and dry soil sites without a flow of water. Higher aerobic and anaerobic bacterial activity was also associated with sediment sites containing organic matter with either a continuous, shallow flow of water are alternate wet/dry periods. Higher fungal activity was associated with alternate wet/dry sediment sites, but only during dry periods. Microbial activity was lowest at sites containing sandy sediments and in water columns.

<p>The removal of vegetation and overburden changes the naturalwater purifying processes and thus decreases the groundwaterprotection in gravel pit areas. The sand and gravel depositsusedfor aggregate extraction in Sweden are also often valuablefor extraction of groundwater as a drinking water resource. TheSwedish legislation requires that gravel pits be restored afterthe cessation of extraction, the aim being to reestablishvegetation and to reinstate groundwater purifyingprocesses.</p><p>The objective of this study was to improve our understandingof the processes governing groundwater protection andvegetation establishment so that these could be applied toimproving restoration methods for reestablishing naturalgroundwater protection. The focus was on the importance of soilphysical properties of the topsoil for vegetation establishmentand groundwater recharge.</p><p>Actual field methods for restoration were reviewed.Conflicts between aggregate extraction and groundwaterinterests were common. In many cases the actual restorationcarried out differed from pre-planned specifications in permitdocumentation.</p><p>Commonly available substrates that might be used forrestoration of gravel pits were investigated. The soils weredescribed as regards texture, organic content, porosity, waterretention and hydraulic conductivity. The way in which acombination of the water retention characteristic and theunsaturated conductivity influenced the behaviour of thesoil-plant-atmosphere system was demonstrated using aprocess-orientated simulation model. Plants with well-developedaboveground characteristics and shallow roots in particularexerted the highest requirements on the soil physicalproperties.</p><p><b>Key words:</b>groundwater protection, soil physicalproperties, CoupModel, unsaturated conductivity, waterretention, transpiration, soil evaporation</p>

The water quality is an essential abiotic factor of the environment, particularly for water-linked ecosystems. It also necessary for human society for which the absence of drinking water could have disastrous consequences. This diploma thesis is focused on small resources of groundwater located in the protected area Křivoklátsko - the springs and wells. A water from the monitored wells was subjected to basic physico-chemical analysis plus some of these wells were also tested for microbiological contamination. These results were presented against current legislation and were also compared with results from Tomáš Brabenec's bachelor thesis. Key words: Křivoklátsko, wells, springs, water quality

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1997 / Detention storage IS a well tested, and generally accepted, method of attenuating flood hydrographs, but relatively littlo data is available from the monitoring of full scale instc'lations An onstrearn pond was constructed at Sunninqhill Park and details of 15 inflow and outflow hydro [Abbreviated Abstract. Open document to view full version] / MT2016

As condições físicas do solo têm efeitos diretos e indiretos na produtividade e na qualidade ambiental. Solos bem agregados, com um manejo adequado, são capazes de manter um balanço de ar e água assim como promover a ciclagem de nutrientes e propiciar o desenvolvimento de raízes. O objetivo desse trabalho foi avaliar o uso do modelo de Dexter índice S, para o mapeamento da qualidade física do solo em uma escala de microbacia hidrográfica (MB) e avaliar o desempenho do modelo indireto de Arya e Paris e programa Qualisolo para a obtenção do índice S. O experimento foi dividido em três etapas: 1) Medida do índice S em uma base de dados de solos contendo 111 amostras e avaliação da sua dependência com a densidade do solo. Em todas as amostras obteve-se o índice S de duas formas: i) a partir da curva de retenção (CR) experimental (SCRexperimental) e ii) por meio da granulometria detalhada, usando o modelo de Arya e Paris com o programa Qualisolo (SCRqualisolo); 2) Estudo do índice S em uma escala de microbacia hidrográfica (MB), 15 parcelas na MB do Ribeirão Canchim, São Carlos, SP, compreendendo classes de solos e coberturas mais comumente encontradas nessa região. 3) Ampliação do estudo do índice S na microbacia, realizando medidas de granulometria, densidade (s), resistência à penetração (RP) e a obtenção do índice SCRqualisolo em mais trinta pontos da MB. Na comparação entre os métodos para o cálculo do índice S verificou-se que SCRexperimental apresentou uma maior variabilidade entre seus pontos, demonstrando ser mais sensível as variações de , textura ou estrutura. Apesar do modelo de Arya e Paris receber uma forte influência da textura do solo, sua determinação integrado ao programa Qualisolo, demonstrou ser uma opção rápida para obter a curva de retenção e o índice S. Com relação ao estudo do índice S na MB, as áreas de pastagem apresentaram os maiores valores de RP, s e relativa e os menores valores de índice S, sendo classificadas como solos de qualidade física pobre. Os valores de S apresentaram a mesma tendência dos parâmetros do solo que estão associados com a qualidade física, que são s e RP, porosidade, curva de retenção e a avaliação qualitativa e quantitativa das imagens de microtomografia que estão associadas com a macroporosidade. Apesar de ser possível uma classificação visual do solo em relação a sua qualidade física, o índice S é possibilita uma avaliação quantitativa e objetiva do estado de degradação física do solo, uma vez que possui uma boa correlação com os demais parâmetros que indicam a qualidade do solo, como observado / The soil physical conditions have direct and indirect effects on plant productivity and environmental quality. Well aggregated soils with appropriate management are able to maintain a good balance between air and water, promote nutrient cycling and good development of roots. The objective of this work was to evaluate the use of the S index of Dexter, for mapping the soil physical quality in a watershed and evaluate the performance of the indirect model of Arya and Paris and the Qualisolo software to estimate the S index. The study was divided into three parts: Measurement of the S index in a database containing 111 soils and the evaluation of their dependence with the soil bulk density (s). For all samples the S index was determined by: i) using the experimental soil water retention curve (SRCexperimental) and ii) using the Arya and Paris model and the Qualisolo software (SRCqualisolo) on measured particle size distribution data; 2) The study of the S index in 15 points of the Ribeirão Canchim watershed, São Carlos, SP, covering the most abundant soil classes and the most commonly used crops in this region; 3) Extension of the S index study to other 30 points where only the SCRqualisolo was determined from measured particle size distribution and compared with measured s and penetration resistance (PR). When comparing the two methods for determining S it was verified that SRCexperimental presented a greater variability among points, showing to be more sensitive to variations in s, texture and structure. Although the significant influence of soil texture on the Arya and Paris model,,the estimation of SCRqualisolo from particle size distribution is very simple and faster than SCRqualisolo and it is an interesting alternative. The areas under pasture presented the lowest S index and the highest s and were classified as low physical quality areas. The S values follow the same trends of the soil parameters associated with soil quality, which are s, PR, porosity, the soil water retention curves and the qualitative and quantitative parameters of the microtomographic images. The S index allows a quantitative and objective measure and expresses the state of physical degradation of soil, since it showed a good correlation with other parameters associated with soil physical quality

O solo fornece suporte e atua como reservatório de água para as plantas, promovendo condições fundamentais ao crescimento de raízes e à dinâmica da água e nutrientes. O conhecimento de suas propriedades hidráulicas, como a curva retenção da água, é de grande importância na descrição e predição dos processos de transporte da água e solutos. O objetivo deste trabalho foi determinar a curva de retenção pelo método tradicional dos funis e câmaras de pressão de ar com placa porosa, pelo método de campo utilizando tensiômetros e pelo método da evaporação da água em amostra de solo no laboratório munida de tensiômetro. O solo utilizado para estudo foi classificado como Nitossolo Vermelho eutrófico de textura argilosa, e estava sendo cultivado com café há mais de 10 anos. A comparação entre as curvas obtidas pelos três métodos indicou que o método da evaporação diferiu estatisticamente do método do funil e câmara e foi estatisticamente idêntico ao método do tensiômetro a campo. Por sua facilidade de execução, baixo custo e rapidez na determinação da curva de retenção até a tensão de aproximadamente 100 kPa, o método da evaporação aqui apresentado é uma boa opção de utilização. Com relação ao método do tensiômetro no campo, embora mais realístico, é muito trabalhoso. / Soil provides support and acts as a water reservoir to plants, promoting essential conditions to root growth and to water and nutrient dynamics. The understanding of its hydraulic properties, like the water retention curve, is of great importance for the description and prediction of the processes of water and solute transport. The objective of this study was to determine soil water retention curve through the traditional method using porous plate funnel and pressure chamber, through the field method using tensiometers and through the water evaporation in soil sample with tensiometer in the laboratory. The studied soil was classified as clayey Rhodic Hapludox, which had been cultivated with coffee for more than 10 years. The comparison of curves obtained through the three methods indicated that the evaporation method was statistically different from the method using funnel and chamber, and statistically equal to the method of tensiometers at field. For its easy execution, low cost and quickness to determine soil water retention curve until the tension of about 100 kPa, the evaportation method presented here is a feasible option. As for the method of tensiometers at field, although it is more realistic, it is very laborious.

L’ajout d’adjuvants dans les mortiers permet d’obtenir diverses propriétés selon lesperformances souhaitées. Les polysaccharides sont utilisés pour améliorer la capacité derétention d’eau et le comportement rhéologique du mortier. Cependant, ils engendrent unretard de prise du ciment et représentent un poids économique considérable. Il apparaît doncque la compréhension de l’interaction entre les polysaccharides et le ciment est nécessaire.Etant donné que les comportements sont différents selon le type de polysaccharide, l’étuded’une nouvelle famille de polysaccharides constitue un axe de recherche majeur. Leshydroxypropylguars (HPG) ont été choisis car ils ont été présentés comme de très bonsagents rétenteurs d’eau et sont déjà utilisés industriellement.Il s’avère que les HPG confèrent effectivement aux mortiers d’excellentes propriétés derétention d’eau. Le mécanisme de rétention d’eau est attribué à la formation d’agglomératsqui, au-delà d’une concentration critique, bouchent le réseau poreux à l’interface mortier-substrat.De plus, ces molécules ralentissent nettement la cinétique d’hydratation du cimenten modifiant la croissance des hydrates par adsorption. Les HPG augmentent également la contrainte seuil de cisaillement et la consistance des mortiers. Toutes cespropriétés diffèrent lorsque les HPG sont introduits pré-dissout dans l’eau de gâchée. Uneméthodologie de fragmentation par ultra-sons des polysaccharides a été développée dans lebut d’étudier l’impact de leur masse moléculaire sur les propriétés des mortiers à l’état frais.Sur tous ces aspects, le comportement des HPG a été comparé à celui des éthers de cellulose,adjuvants rétenteur d’eau de référence. / Modern factory-made mortars are complex materials, in which are added some kinds of admixtures used to exhibit various properties. Polysaccharides are admixtures used in order to improve water retention capacity and rheological behavior of freshly-mixed mortars.However, polysaccharides induce a delay of cement hydration and represent a large part of mortar raw material cost. The improvement of the knowledge about polysaccharide-cement interaction is therefore necessary. In past, different behaviors were observed according to the kind of polysaccharide. The study of a new polysaccharide family is thus a major way of research. The hydroxypropylguars were chosen since they were presented as promising water retention agents and they are now well-established in the construction industry.Results show that HPG improve the water retention capacity of cement-based mortars. The working mechanism is attributed to the formation of HPG aggregates above a critical dosage, which may stop the water flow by plugging the porous network at the interface mortar-substrate. Moreover, HPG induce a decrease in the hydrates growth rate because of adsorption on the cement hydrated phases, and enhance the consistency and the yield stress of mortars. All these properties are influenced by the pre-dissolution of HPG in the mixing water. A methodology of ultrasonic degradation was also established in order to study the molecular weight influence of polysaccharides on fresh-state properties. Cellulose ethers were systematically investigated as polysaccharidic admixture reference.

Modern urban stormwater infrastructure includes vegetated bioretention facilities (BRFs) that are designed to detain water and pollutants. Phosphorus (P) is a pollutant in stormwater which can be retained in BRF soils in mineral, plant, and microbial pools. We explored soil properties and phosphorus forms in the soils of 16 operational BRFs in Portland, OR. Since soil hydrology can significantly impact P retention, we selected BRFs along an infiltration rate (IR) gradient. We conducted sequential fractionation and tests of P pools and measured P release in a subset of soils after drying and flooding samples for ten days. We hypothesized that mineral or organic soil P forms would be correlated with IR, and that vulnerability to P release would depend on the interaction of drying and flooding treatments with P forms and pools. IR did not significantly explain differences in P forms. Soil TP was elevated across all sites, compared with TP in agriculturally-impacted wetlands and was substantially composed of soil organic matter (OM)-associated P. Phosphorus sorbed to mineral Fe and Al oxides- was variable but positively correlated with water-extractable P. The concentration gradient of water-extractable P was primarily controlled by overall P pools. Experimentally induced P releases were seen in 5 of 6 soils exposed to drying conditions, presumably released through microbial mineralization of OM. Only one site showed significant P release following the flooding treatment. Our measurements supported the idea that Fe and Al oxides provide P sorption capacity in these BRF soils. Variable inputs of P to BRFs through stormwater and litterfall may contribute to variability in P profiles and P release vulnerability across sites. Design specifications and management decisions relating to bioretention soils (e.g. establishment of acceptable soil test P levels, focusing on P forms known to influence vulnerability of P release) may benefit from detailed biogeochemical investigations.

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Doctor of Philosophy(PhD) / In eastern Australia, Vertosols are widely utilised for the production of irrigated cotton (Gossypium hirsutum) due to their inherent fertility and large water–holding capacity. However, irrigated agriculture in eastern Australia is faced with a decline in the availability of good quality irrigation water sources i.e. waters with low electrolyte concentrations and small Na+ contributions. Consequently, alternative water resources that contain larger contributions of Na+ are becoming increasingly relevant as potential irrigation sources. It is known that the application of Na+ rich waters as irrigation has the potential to increase the Na+ content of the soil, and that this will affect the structural condition of Vertosols. However, the extent to which these poor quality water resources will influence the structural characteristics of different Vertosols is unknown. In addition to this knowledge gap, there is currently no suitable predictor of dispersive behaviour for this soil type, particularly where Vertosols are irrigated with different water quality solutions. The research conducted in this study aimed to characterise the impact of different increments of water quality on the structural stability of different Vertosols. Once this was concluded, the study looked to assess the impact of irrigation water quality on the structural stability, structural form and soil water retention properties of intact soil columns. Knowledge of the structural stability of the soils investigated was then used to derive a model describing the impact of water quality on the structural stability of different cotton producing soils. To achieve the aims nine different soil profiles were sampled from the Bourke, lower Gwydir, Hillston and lower Namoi cotton–producing regions. Eight of these soils are Grey and Black Vertosols with clay phyllosilicate suites dominated to different extents by 2:1 expanding clays, and the ninth soil is an illitic Red Vertosol containing small contributions of 2:1 expanding clays. The soils investigated have ESPs that range between 1 and 10, ECs of 0.1 to 1.2 dS m-1 and CECeff values that are largest for those soils that contain more 2:1 expanding clays. This study shows that the clay phyllosilicate suite of different Vertosols is the primary determinant of structural stability, structural form and soil water retention properties. For example, the Gwydir and Namoi soils contain more 2:1 expanding lattice phyllosilicate clays, have the largest CECeff values of all nine soils and are the most dispersive after all applied immersion treatments. The Bourke and Hillston soils contain less 2:1 expanding lattice clay, have smaller CECeff values and are generally more stable. Irrigation of structurally–intact soils with solutions of larger SARw resulted in larger exchangeable Na+ contents for each soil (and larger ESPs) and smaller contributions of exchangeable Ca2+ and Mg2+. For each soil, larger ESPs are reflected by decreased stability, but generally the soils dominated by 2:1 expansive clays are much less stable than the soils containing smaller contributions of these clay mineral types. Irrigating the structurally–intact Vertosols dominated by 2:1 expansive clays generally resulted in structural form attributes that do not indicate any impact of the applied water treatments, but the Vertosols with less of these mineral types tend to have less desirable structural form attributes after irrigation with solutions of larger Na+ content. Similarly, where the water retention properties of two soils were assessed, the illitic Red Vertosol has less structural pore space after treatment using the large SARw solutions, while the other soil (a Black Vertosol dominated by 2:1 expansive clays) does not show any differences between water retention properties that can be linked to irrigation water quality. These results were clarified for the water retention properties by the assessment of pore–solid space relations, which show both these soils to contain less solid space after irrigation with clean water or solutions of large SARw. This is attributed to increased swelling of clays in the presence of larger Na+ contributions, but both soils have different structural arrangements as shown by the water retention properties and structural form assessment. The red illitic Vertosol shows signs of structural collapse, while the black Vertosol maintains its structural arrangement. Finally, a model describing the structural stability of different Vertosols was developed from the stability assessment of soils, both in different water quality treatments and after the irrigation of structurally–intact columns. The model presented uses a surface response function to describe the impact of increased ECw and SARw of irrigation solutions on soil stability after immersion according to specific soil physico–chemical attributes. In this model increased exchangeable Na+, SAR and a larger CECeff (and consequently, an increased proportion of 2:1 swelling clays) are associated with increases in clay dispersion, while a smaller Ca2+:Mg2+ ratio, EC and less total clay are associated with decreases in clay dispersion.