Hydraulic tomography is a cost -effective technique for characterizing the heterogeneity of hydraulic parameters in the subsurface. During hydraulic tomography surveys, a large number of hydraulic heads (i.e., aquifer responses) are collected from a series of pumping or injection tests in an aquifer. These responses are then used to interpret the spatial distribution of hydraulic parameters of the aquifer using inverse modeling. In this study, we developed an efficient sequential successive linear estimator (SSLE) for interpreting data from transient hydraulic tomography to estimate three-dimensional hydraulic conductivity and specific storage fields of aquifers. We first explored this estimator for transient hydraulic tomography in a hypothetical one-dimensional aquifer. Results show that during a pumping test, transient heads are highly correlated with specific storage at early time but with hydraulic conductivity at late time. Therefore, reliable estimates of both hydraulic conductivity and specific storage must exploit the head data at both early and late times. Our study also shows that the transient heads are highly correlated over time, implying only infrequent head measurements are needed during the estimation. Applying this sampling strategy to a well -posed problem, we show that our SSLE can produce accurate estimates of both hydraulic conductivity and specific storage fields. The benefit of hydraulic tomography for ill -posed problems is then demonstrated. Finally, to affirm the robustness of our SSLE approach, we apply the SSLE approach to transient hydraulic tomography in a hypothetical two- dimensional aquifer with nonstationary hydraulic properties, as well as a hypothetical three-dimensional heterogeneous aquifer.

Increasing urbanization is often accompanied by problematic changes in watershed hydrology. Decreasing surface permeability can lead to increased overland flow volumes, which may spread surficial contaminants and increase the strain on municipal stormwater infrastructure. This study examines a mixed-use property in the Proctor Creek watershed in Atlanta, Georgia, to better understand how land-management practices influence soil overland flow potential. Field saturated hydraulic conductivity (Kfs) measurements were collected from soils 1) subjected to compaction, 2) in urban agricultural use, and 3) under common lawn maintenance. Mean values were 9.1E-7 cm/s, 2.2E-4 cm/s, and 9.0E-6 cm/s respectively. Measurements were collected in-situ with the use of the Aardvark constant-head permeameter. Statistical analyses indicated a substantial difference in Kfs based on land-management practices and that urban farming can increase soil Kfs and limit overland flow. Additional analysis revealed no significant difference in grain-size distributions suggesting land-management practices controlled Kfs, not soil texture.

<p>Over an extended period of time there have been plans to establish a shared facility in Lennheden to extract groundwater from the Badelunda esker to provide drinking water for the cities of Borlänge and Falun. The city of Falun is dissatisfied with the quality of its drinking water and the city of Borlänge is concerned about the risk of contamination of its existing groundwater supply at its current location. To provide a basis for a decision on this issue, the company Midvatten AB has been commissioned to perform hydrogeological investigations in the area of Lennheden.</p><p>The purpose of this thesis is to design a functional groundwater model of the area between Lennheden, place of planned extraction, and Övre Tjärna, place of existing extraction, to get a better understanding of the groundwater situation in the area. A groundwater model enables simulations of different scenarios in risk assessment and contaminant transport. The aim of the thesis is that the model can be used as an aid in Midvatten’s investigations in Lennheden and that it also can be used in future projects in the area.</p><p>The model has been made in Processing Modflow 5.3 and encompasses an area of 19,5 × 11 km along the Badelunda esker and the river Dalälven between Djurmo and Frostbrunnsdalen. The model has 6 layers and a cell resolution of 50 × 50 meters and 50 × 100 meters. The physical parameters of the model are comprised from different hydrological and geological investigations in the area.</p><p>The Badelunda esker and the river Dalälven totally dominate the groundwater situation in the area. A large part of the work in the thesis has been focused on the calibration of the horizontal hydraulic conductivity in the esker and the vertical hydraulic conductivity in the riverbed of Dalälven. The calibration of the model implies a vertical hydraulic conductivity of 0,01 – 0,1 md-1 in the riverbed of Dalälven, depending on the riverbed thickness.</p><p>Between Bäsna and Övre Tjärna, simulated and observed groundwater levels correspond well. The transport time of the water in the esker, simulated in PMPATH, also corresponds well with estimated transport times. The model can be used for simpler studies of contaminant transport.</p><p>Simulation of the pumping test in Lennheden gives a good correspondence eastward in the esker from Lennheden to Övre Tjärna. Westward in the esker, from Lennheden to Bäsna, the draw down is sharper than observed. Possible reasons for the sharper draw down is an underestimation of the bulk of the esker and that the vertical hydraulic conductivity of the riverbed is set too low between Lennheden and Bäsna.</p><p>In order to improve the model, the most important step should be to thoroughly investigate the river Dalälven with regards to vertical hydraulic conductivity in the riverbed and riverbed thickness.</p> / <p>Under en längre tid har det funnits planer på att upprätta en ny, gemensam vattentäkt för Borlänge och Falu kommun i Badelundaåsen i Lennheden nordväst om Borlänge stad. Falu kommun är missnöjd med vattenkvaliteten i sin ytvattentäkt och Borlänge är oroad över riskerna med att ha sin nuvarande vattentäkt i Badelundaåsen lokaliserad i nära anslutning till riksväg 70 och järnvägen. Beslut i frågan ska tas under 2006 och Midvatten AB har fått i uppdrag att genomföra geohydrologiska undersökningar i och runt Lennheden som underlag till beslutet.</p><p>Syftet med det här examensarbetet är att skapa en fungerande grundvattenmodell för området mellan Lennheden, plats för planerat vattenuttag, och Övre Tjärna, plats för befintligt vattenuttag, för att få en större förståelse för grundvattenmagasinet. En grundvattenmodell möjliggör simulering av olika scenarion så som föroreningstransport i grundvattnet och bestämning av skyddsområden. Målet är att modellen ska kunna användas som ett komplement i Midvattens undersökningar och även användas i framtida projekt i området.</p><p>Modellen är gjord i Processing Modflow 5.3 och omfattar ett 19,5 × 11 km stort område längs Badelundaåsen och Dalälven mellan Djurmo och Frostbrunnsdalen. Modellen består av 6 lager där cellernas upplösning är 50 × 50 meter och 50 × 100 meter. De fysiska parametrar som modellen är uppbyggd av är sammanställda från olika hydrologiska och geologiska undersökningar som har utförts i området de senaste 30 åren.</p><p>Badelundaåsen och Dalälven är de två komponenter som totalt dominerar grundvattensituationen i området. En stor del av arbetet har fokuserats på kalibreringen av den horisontella hydrauliska konduktiviteten i åsen och den vertikala hydrauliska konduktiviteten i Dalälvens botten. I modellen är den vertikala hydrauliska konduktiviteten i Dalälvens botten kalibrerad till intervallet 0,01 – 0,1 md-1 beroende på bottnens mäktighet.</p><p>På sträckan mellan Bäsna och Övre Tjärna så fungerar modellen bra. Simulerade och observerade grundvattennivåer stämmer väl överens. Även vattnets transporttider i åsen, simulerade i PMPATH, stämmer väl överens med uppskattade transporttider. Modellen kan användas för enklare studier av ämnestransport.</p><p>Vid simulering av provpumpningen i Lennheden så är överensstämmelsen god österut i åsen, från Lennheden till Övre Tjärna. Västerut i åsen, från Lennheden till Bäsna, är avsänkningen av grundvattennivån för kraftig. Möjliga orsaker till den för kraftiga avsänkningen är att åsens utbredning är underskattad och att Dalälvens botten har en för lågt ansatt vertikal hydraulisk konduktivitet längs sträckan Lennheden – Bäsna.</p><p>Den klart viktigaste åtgärden för att förbättra modellen skulle vara att grundligt undersöka Dalälven, särskilt längs sträckan Djurmo – Båtsta, med avseende på dess bottens vertikala hydrauliska konduktivitet och mäktighet.</p>

The purpose of this study was to evaluate Lewis (2016) simple method to determine hydraulic conductivity in soil samples. This was conducted by comparing Lewis method to a slug-test, Guelph permeameter and calculations from grain size analysis in order to find out if the method is a reliable source for measuring hydraulic conductivity. Other parameters to compare is time consumption, cost effectiveness and area of use. Four different samples were used in the testing, a sand, two tills and pyrite ash (which is a rest product from manufacturing sulfite pulp). The results indicated that measurements in the homogenic sand all methods was in a good range of each other, while in the more heterogenic till the slug-test and Lewis method was close and the calculations from grainsize analysis was much lower. Only grainsize analysis was performed on the pyrite ash and the results was similar to Lewis method. This study shows that Lewis method works well as a reliable source for K measurements and is less time consuming than all the other methods. The material required for the method can be obtained in a hardware store.

The objective of this study was to investigate the spatial relationship between the most likely distribution of saturated hydraulic conductivity (K-s) and the observed pressure head (P) distribution within a hillslope. The cross-correlation analysis method was used to investigate the effects of the variance of lnK(s), spatial structure anisotropy of lnK(s), and vertical infiltration flux (q) on P at some selected locations within the hillslope. The cross-correlation analysis shows that, in the unsaturated region with a uniform flux boundary, the dominant correlation between P and Ks is negative and mainly occurs around the observation location of P. A relatively high P value is located in a relatively low Ks zone, while a relatively low P value is located in a relatively high Ks zone. Generally speaking, P is positively correlated with q/Ks at the same location in the unsaturated region. In the saturated region, the spatial distribution of K-s can significantly affect the position and shape of the phreatic surface. We therefore conclude that heterogeneity can cause some parts of the hillslope to be sensitive to external hydraulic stimuli (e.g., rainfall and reservoir level change), and other parts of the hillslope to be insensitive. This is crucial to explaining why slopes with similar geometries would show different responses to the same hydraulic stimuli, which is significant to hillslope stability analysis. (C) 2016 Hohai University. Production and hosting by Elsevier B.V.

Woody plant expansion has been documented for decades in many different ecosystems, often due to anthropogenic disturbances to the environment and yielding vast changes in ecosystem functioning. While causes and consequences of woody expansion have been well documented, few studies have investigated functional traits of woody species that promote rapid expansion in range. My objective was to determine if hydraulic efficiency confers enhanced photosynthetic efficiency so that functional traits representing light and water use may be possible mechanisms facilitating woody encroachment into grasslands and forest understories. I quantified leaf-level light environment, photosynthetic activity, and hydraulic characteristics of three sympatric broadleaf evergreens of varying leaf life span (Ilex opaca, Kalmia latifolia, and Myrica cerifera) in a deciduous forest understory to understand seasonal intra- and interspecific ranges of broadleaf evergreen physiology. Additionally, I investigated the effects of age on physiological efficiency of M. cerifera across a chronosequence (i.e., space for time substitution) of shrub thicket development in order to understand possible age-related physiological mechanisms facilitating shrub expansion. Lastly, I determined functional traits and resulting physiology that contribute to rapid expansion and thicket formation of an invasive, deciduous, N-fixing shrub, Elaeagnus umbellata, and a native, evergreen, N-fixing shrub M. cerifera. When compared to co-occurring evergreen species, electron transport rate (ETR) of M. cerifera was nearly double that of I. opaca or K. latifolia in summer. Photosynthetic capacity was positively related to hydraulic capacity among understory evergreens. Furthermore, photosynthetic and hydraulic efficiency of M. cerifera remained consistent despite considerable differences in thicket age and development. Both similar and contrasting functional traits of E. umbellata and M. cerifera allowed for enhanced light capture and water movement, and reductions in subcanopy light penetration. Enhanced hydraulic and photosynthetic efficiency relative to co-occurring species contributes to rapid range expansion and thicket formation by promoting enhanced productivity and limiting successful colonization of other species. My results indicate that there may be suites of functional traits linked to expansive success and thicket-formation, yet differences in functional traits between native and invasive species represent alternative strategies leading to rapid growth and thicketization.

The objective of this study is to estimate 2-D spatial distribution of hydraulic conductivity (Ks) of Zhuoshui River alluvial fan, Taiwan, using groundwater level data from 88 wells and stream stage data from 4 gauging stations. In order to accomplish this analysis, wavelet analysis is first carried out to investigate the periodic cycles of groundwater level, precipitation, and stream stage. The results of the analysis show that variations of groundwater level and stream stage are highly correlated in terms of seasonal and annual periods. Subsequently, seasonal variations of groundwater level in response to stream stage variation are utilized to estimate the Ks spatial distribution by spatiotemporal cross correlation analysis, cokriging, and river stage tomography. Prior to applications of these methods to the alluvial fan, performances of each approach are evaluated and compared with reference field of a noise free synthetic experiment. It is found that all of the approaches could yield similar general spatial pattern of Ks. Nevertheless, river stage tomography seems to reveal a higher resolution of spatial Ks distribution. When the geologic zones are provided in river stage tomography analysis as prior information, the accuracy of estimated Ks values improves. Finally, results of the applications to data of the alluvial fan reveal that the apex and southeast of the alluvial fan are regions with relative high Ks and the Ks values gradually decrease toward the shoreline of the fan. These two areas are considered as the possible main recharge regions of the aquifer. It is also observed that Ks at northern alluvial fan is slightly larger than that at southern. These findings seem consistent with the geologic evolution of this alluvial fan.

As propriedades hidráulicas do solo de interesse são a curva de retenção da água no solo, a condutividade hidráulica e difusividade hidráulica, ambas em função do conteúdo de água no solo. Estas propriedades dependem do tamanho, forma, distribuição e grau de interconexões dos poros. O método do perfil instantâneo é um dos métodos mais utilizados na determinação da condutividade hidráulica do solo não saturado pela sua simplicidade experimental e matemática. Assim, este projeto visa avaliar a) a condutividade hidráulica em função do conteúdo de água em dois solos bem distintos estruturalmente pelo método do perfil instantâneo, com e sem a remoção de horizontes sobrejacentes, estimando o conteúdo de água via curvas de retenção determinadas em laboratório e em campo, e b) o sistema poroso do solo por meio de técnicas de análise de imagens e correlacionar os resultados à condutividade hidráulica do solo não saturado obtido pelo método do perfil instantâneo. O experimento foi conduzido em quatro horizontes de um Latossolo e de um Nitossolo. A CRA em campo foi elaborada utilizando-se tensiômetros com manômetro de mercúrio, enquanto que a CRA em laboratório foi determinada com amostras de solo com estrutura indeformada em funis de placa porosa e em câmara de pressão com placa porosa. A condutividade hidráulica não saturada foi determinada pelo método indireto em laboratório e em campo, seguindo a metodologia do método do perfil instantâneo, sem e com a remoção dos horizontes sobrejacentes. De acordo com os resultados obtidos, pode-se concluir que: (a) os valores do conteúdo de água médio à base de volume para cada tensão em campo foram menores que os obtidos em laboratório em praticamente todas as tensões; (b) a eficiência da equação de ajuste da curva de retenção da água foi maior para o método de laboratório; (c) as análises micromorfométricas tenderam a subestimar os valores de área de poro para todas as classes de tamanho de poros e horizontes; (d) a análise micromorfométrica fornece uma estimativa do grau de interconexões do sistema poroso; (e) pequenas mudanças no conteúdo de água no solo afetam o valor de difusividade hidráulica em um grau muito menor que a condutividade hidráulica; e (f) é necessário ter cautela ao utilizar dados de laboratório para representar as condições de campo, visto que os valores de K(&theta;) foram superestimados pela CRA obtida em laboratório, em relação ao método de campo, ocorrendo de forma mais pronunciada nas menores tensões da água no solo. / The soil hydraulic properties of interest are the soil water retention curve, hydraulic conductivity and hydraulic diffusivity, both as a function of the soil water content. These properties depend on the size, shape, distribution and degree of pore interconnections. The instantaneous profile method is one of the most used methods to determine the unsaturated hydraulic conductivity due to its experimental and mathematical simplicity. Thus, this project aims to evaluate a) hydraulic conductivity as a function of water content in two distinct structured soils by the instant profile method, without/with removal of overlying horizons, estimating the soil water content through retention curves determined in the laboratory and in the field, and b) the soil porous system using image analysis techniques and correlation the results to the unsaturated hydraulic conductivity obtained by the instant profile method. The experiment was conducted on four horizons of a Ferralsols and a Nitisol. The SWRC was made with tensiometers with mercury manometers, while a SWRC in the laboratory was made with undisturbed soil samples in porous plate funnels and in porous plate pressure chamber. The unsaturated hydraulic conductivity was determined by the indirect method in the laboratory and using the instant profile method in the field, without/with removal of the overlying horizons. The conclusions are: (a) the water content for each tension in the field are smaller than those obtained in the laboratory at practically all tensions; (b) the efficiency of the water retention curve fitting equation was greater for the laboratory method; (c) the micromorphometric analysis tended to underestimate pore area values for all pore size classes and horizons; (d) the micromorphometric analysis provides an estimation of the porous system interconnections degree; (e) small changes in soil water content affect the hydraulic diffusion values to a much lower degree than the hydraulic conductivity; and (f) it is necessary to take care in using laboratory data to represent field conditions, since the values of K(&theta;) were overrated by the laboratory SWRC, compared to the field, more pronounced in smaller water tensions.

Barreiras impermeáveis são uma necessidade em várias obras de engenharia e, em geral, naquelas destinadas à disposição de resíduos, como os aterros e as lagoas de efluentes. Solos compactados têm sido largamente utilizados para essa finalidade. Nesse sentido, esses solos devem ter características apropriadas, como baixa permeabilidade, as quais devem permanecer frente às solicitações de obra. Este trabalho trata do estudo da potencialidade do uso de solos lateríticos compactados em barreiras impermeáveis para sistemas de contenção de resíduos. Neste estudo avaliaram-se os efeitos da umidade e da energia de compactação em duas propriedades importantes para a finalidade desejada, a permeabilidade e a contração, por meio de corpos de prova de dimensões reduzidas, tal qual utilizado na metodologia MCT. Verificou-se que, em geral, a condutividade hidráulica diminuiu com o aumento da umidade, até a umidade ótima, permanecendo praticamente constante ou diminuindo ligeiramente a partir daí. O aumento da energia de compactação diminuiu as condutividades hidráulicas de forma pronunciada no ramo seco da curva de compactação, mas após a umidade ótima as variações foram pequenas para energias acima de 12 golpes. As mínimas condutividades hidráulicas obtidas foram da ordem de '10 POT.-7' cm/s para vários solos ensaiados. Outro fator que também influenciou na diminuição da condutividade hidráulica dos solos foi o aumento da porcentagem de argila. No que se refere às contrações dos solos, o aumento da umidade acarretou em aumento das contrações axiais, que atingiram valores máximos da ordem de 4%. Os solos mais arenosos apresentaram as menores contrações axiais, não ultrapassando valores da ordem de 1%, enquanto para os solos argilosos as contrações médias foram da ordem de 2%. O aumento da energia de compactação acarretou ligeiro aumento das contrações axiais / Impermeable barriers are a need in several engineering works, specially in waste containment systems and effluents ponds. Compacted soils have been used for that purpose. In that sense, the candidate soils should have appropriate characteristics, such as low permeability, which must remain throughout the design life. This work deals with the potentiality of using lateritic compacted soils in impermeable barriers for waste containment systems. In this study the influence of the water content and the compacting energy on the permeability and on the shrinkage of those soils was studied, through specimens of reduced dimensions, as used in the MCT methodology. It was verified that, in general, the hydraulic conductivity decreased with the increase of the water content, until the optimum water content, staying practically constant since then. The increase of the compacting energy reduced the hydraulic conductivities in the dry side of the compacting curve, but beyond the optimum water content the variations were small for energies larger than 12 blows. The lower hydraulic conductivities obtained were of the order of '10 POT.-7' cm/s for several soils. Hydraulic conductivity was also reduced with the increase of the clay percentage. Regarding soil shrinkage the increase of the water content caused an increase on the axial shrinkage that reached maximum values in the order of 4%. The sandy soils presented the smallest axial shrinkage (lower than 1%), while for the clayey soils the average shrinkage reached about 2%. The increase of the compacting effort caused a little increase of the axial shrinkage

O conhecimento dos processos que envolvem o movimento da água no solo e de fundamental importância para o manejo e a conservação do solo e da água. Ha situações em que, durante um evento de chuva intensa, a água se move mais rapidamente no perfil através de canais, sem que haja interação com a matriz do solo; esse movimento e chamado de fluxo preferencial. Atualmente e aceita em estudos de campo a existência deste fluxo preferencial em uma ampla variedade de solos. No entanto, muitos métodos utilizados para determiná-lo diretamente alteram o fluxo da água através da matriz do solo, processo de drenagem de relevância indiscutível nos solos. Em trabalho recente realizado no Japão, esse problema foi superado com sucesso pela aplicação concomitante, durante e um pouco após os eventos de chuva, da equação de Darcy-Buckingham e do método do balanço de água no solo: a equação de Darcy-Buckingham infere sobre a presença de fluxo preferencial da água, definido, nessa abordagem, como o resíduo da equação do balanço de água no solo durante os eventos de chuva. Este método apresenta, portanto, a grande vantagem de tornar possível a determinação experimental do fluxo preferencial a uma dada profundidade do solo, em condições de campo, sem interromper significativamente o fluxo mátrico de água. O objetivo deste trabalho foi a determinação e caracterização do fluxo preferencial da água nas profundidades correspondentes aos horizontes B textural e B latossólico de um Nitossolo Vermelho eutrófico em condições de campo, aplicando a equação de Darcy-Buckingham e o método do balanço de água no solo, durante e um pouco após os eventos de chuva. Devido ao baixo volume de chuva durante a última estação chuvosa, em apenas duas situações foi possível reconhecer uma alteração significativa na umidade do solo em profundidades superiores a 0,5m e nas duas situações foi verificada fluxo preferencial no horizonte Bt, não foi verificado fluxo preferencial no horizonte Bw durante os eventos chuvosos avaliados. A metodologia utilizada foi eficiente na observação de fluxos de água no solo que não são influenciados pela matriz. / The understanding of the processes involving soil water movement is essential to soil and water management and conservation. There are situations in which the water moves faster in the soil profile through channels, during an event of intense rain, without interacting with soil matrix; this movement is known as preferential flow. Currently, it is accepted in field studies the existence of preferential flow in a wide range of soils. Nevertheless, many methods used to directly determine it change the water flow through the soil matrix, a drainage process of unquestionable relevance in soils. In a recent study carried out in Japan, this problem has been successfully overcome by simultaneously applying Darcy-Buckingham\'s equation and the soil water balance method during and shortly after rain events; the Darcy-Buckingham\'s equation infers on the presence of preferential water flow, defined in this approach as the residue of the soil water balance equation during the rain events. Therefore, this method has the great advantage of making possible the experimental determination of the preferential flow at a certain depth in soil, in field conditions, without significantly interrupting matric water flow. This study aimed to determine and characterize preferential water flow in depths corresponding to textural and latosolic B horizons of a Eutrophic Red Nitosol in field conditions, applying Darcy-Buckingham\'s equation and the soil water balance method, during and shortly after rain events. Due to the low volume of rain in the last rainy season, a significant change in soil moisture below 0.5 m was only observed in two situations, where preferential flow in Bt horizon was also verified. Preferential flow was not verified in the Bw horizon during the analyzed rain events. The methodology used was efficient in the observation of soil water flows not influenced by the soil matrix.