The overall objective of this thesis is to better understand and assess pesticide leaching at the regional scale, using both the analysis of monitoring data and spatially distributed modelling. Atrazine contamination of the Brusselian aquifer (central Belgium) is poorly understood. Considerable uncertainty surrounds whether the pollution is agricultural or non-agricultural in origin. The spatial and temporal covariance of atrazine concentrations was studied by fitting semivariogram models to monitoring data. Correlation ranges were found to be 600 metres and 600-700 days. A non-parametric one-way ANOVA found a strong relationship between mean concentrations and land use, whilst other environmental variables were found to be less important. Higher levels of pollution were detected in areas dominated by urban land use suggesting that atrazine residues in groundwater resulted from non-agricultural applications. Modelling pesticide leaching at the regional scale (Dyle catchment) was used to assess groundwater vulnerability. Different approaches to process soil information were tested with both a linear (modified Attenuation Factor) and a non-linear (GeoPEARL) leaching model. The CI (calculate first, interpolate later) and IC (interpolate first, calculate later) approaches were identical for the linear model, but differences in the amount of leaching were found for the non-linear model. The CI approach would be expected to give better results than IC, but the CA (calculate alone) approach is probably the best method if no spatial output is required. Finally, a methodology was developed to quantify the uncertainty arising from the spatial variability of non-georeferenced parameters (i.e. those assumed to be spatially constant in deterministic simulations). A Monte Carlo analysis of atrazine leaching was performed with six pesticide and soil properties as uncertain inputs. Spatial variability of non-georeferenced parameters had a significant influence on the amount of simulated leaching. In the stochastic simulation, concentrations exist above the regulatory level of 0.1 µg/L, while virtually no leaching occurred in the deterministic simulation. Including the spatial variability of substance parameters (half-life, sorption coefficient...) would have significant consequences for future registration policies, especially if risk assessments are implemented in a spatially distributed way.

Research has long recognized and studied the dynamics of groundwater processes. More recently, groundwater dependent ecosystems (GDEs) are being recognized for their diversity and vulnerability to anthropogenic impact. Groundwater in karst landscapes presents a distinctive situation where flow through the subsurface often moves rapidly on the scale of days and weeks as opposed to years or millennia in other systems. This distinctive situation of karst systems and their vulnerability to human impacts necessitate an integrated and multifaceted approach for the management of these important resources. However, development of such an approach is complicated by the difficulty of obtaining detailed data about the ecosystem, especially in remote areas of developing countries. Additionally, management difficulties related to political boundaries, jurisdictions, and land ownership can result in ineffective and inconsistent policies and practices across a single catchment. In order to address these issues, this dissertation creates a new composite model for groundwater dependent ecosystem (GDE) management in areas of karst development. Within this new composite model, the combination of the Karst Disturbance Index (KDI) and groundwater vulnerability mapping recognizes both human disturbance and how the physical nature of the karst will enhance this impact. These studies bridge the gap between science and management by connecting the final model to management strategies for a sub-catchment of the Rio la Venta watershed, the majority of which is within the Reserva de la Biosfera Selva el Ocote in Chiapas, Mexico. This composite model serves as an adaptable spatial tool for management planning and protection for all components of the karst environment.

The environmental impact of transportation construction, operation and maintenance is of critical importance. Therefore it is vital to carry out a groundwater vulnerability assessment for transportation projects at an early stage. The objective of the study was to apply a methodology for groundwater vulnerability assessment for transportation planning in order to identify and avoid areas susceptible to contamination. In this study a spatial multi criteria analysis (SMCA) was conducted where the impacts of railroads on groundwater were examined. Physical factors that influence the groundwater vulnerability such as infiltration capacity, hydraulic conductivity, effective porosity, slope, land cover, depth to groundwater and topographic wetness index (TWI) were considered in this study. Results from the study show that about 30% of the total area was prone to high and very high groundwater vulnerability. The final vulnerability map illustrated the highly vulnerable areas in the sand deposits and till and less vulnerable areas of rock outcrops and clay deposits. According to the outcome of the sensitivity analysis the methodology used in this study shows promising results and can be employed further with some improvements. / På grund av ökad efterfråga på transport planerar Stockholms Lokaltrafik (SL) en ny järnväg i norra Stockholm mellan Vallentuna kommun och Arlanda flygplats (Sveriges största internationella flygplats). Väg- och järnvägskonstruktion och underhåll förorenar inte bara luft, mark och närliggande vattendrag utan även den mättade zonen genom infiltrerande vatten. Denna studie fokuserar på effekterna av järnvägen på grundvattnet, eftersom grundvatten är en viktig resurs för vattenförsörjning (hushåll, industri etc.) Syftet med denna studie var att utveckla en modell för sårbarhetsanalys av grundvatten för transportplanering genom Multi Criteria Analysis (MCA) och geografiska informationssystem (GIS). För att hantera detta komplexa problem har sju kriterier kritiska för grundvattnets sårbarhet identifierats (t.ex. hydraulisk konduktivitet, infiltration och effektiv porositet, djup till grundvatten, marktäcke, topografisk wetness index (TWI) och lutning); viktats med tanke på dess påverkan på grundvattnet och dess noggrannhet i data; och till sist kombinerats för att framställa en grundvattensårbarhetkarta. GIS (ArcGIS) verktyg användes i studien för att hantera rumslig heterogenitet inom det studerade området samt komplexiteten av MCA. För att utvärdera påverkan av varje kriterium på resulterad sårbarhetskarta tillämpades enda variabel metoden. Genom att jämföra värdena från den teoretiska viktningen (tilldelade värden) och den effektiva viktningen (beräknade värden) för varje kriterium kunde det mest inflytelserika kriteriet identifieras. Som ett resultat av studien, producerades en grundvattensårbarhetskarta över det studerade området vilket indikerade att sand och moränavlagringar är mycket känsliga för föroreningar på grund av hög infiltrationskapacitet i grovkornig jord, högt värde av hydraulisk konduktivitet och effektiv porositet. Men på grund av låg infiltration och hydraulisk konduktivitet tillsammans med låg effektiv porositet, erhöll lera som ligger på låga upphöjda områden det lägsta värdet av sårbarhet.

>Magister Scientiae - MSc / Aquifer vulnerability assessment is increasingly becoming a very significant basis in order to fulfil the water demands in South Africa. Knowledge of soil hydraulic properties that consists of the soil water retention and hydraulic conductivity functions is a prerequisite for predicting solution transport in soils. The overall objective of the study is to develop a database of hydraulic properties for collected undisturbed samples and to test selected models by making use of this database. Studies of the vadose zone are generally restricted to the top 1.2 meters; therefore this study aims at essentially improving the lack of measurements and modelling in the vadose zone. There exist several methods to determine hydraulic properties of soil that make use of hydraulic conductivity (K) determination in the vadose zone. The most accurate estimates of hydraulic conductivity are possible through direct measurements or measurements of the water retention curve. For this study, the drilling and sampling of five boreholes (maximum depth 20 m) proceeded during March and April 2005 at two typical sites in the Western Cape, namely the Berg river site (Riebeek West) and Ithemba site (Cape Flats). In total, 76 undisturbed core samples were collected from which the detailed borehole log descriptions were made. The determination of the soil water retention curves of the collected samples was based on laboratory techniques using Eijkelkamp drying and suction equipment (sand box and clay box). When modelling groundwater vulnerability, it is essential to look at the soil water retention curves with increased importance, as they provide graphical and mathematical confirmation of porosity, preferential flows, volumetric water content and unsaturated hydraulic conductivity. Therefore, a numerical model called RETC was used to determine soil hydraulic properties. The RETC model uses equations of Van Genuchten (Van Genuchten, 1980) and Brooks-Corey (Brooks and Corey, 1966) to determine parameters for soil water retention and the methods of Mualem (1976) and Burdine (1953) to determine unsaturated hydraulic conductivity functions. Saturated hydraulic conductivity values were estimated by using RETC soil database based on textural descriptions of collected samples. Using the soil hydraulic estimates obtained from RETC, sensitivity analyses were run with a one dimensional transport model, Macro 5.0 for two sites at iThemba and in the Berg river.

<p>The focus of this thesis is on groundwater vulnerability assessment by process-based simulation models and data acquisition for these assessments. A modelling system for intrinsic groundwater vulnerability assessment in water supply areas was developed, consisting of flow- and transport models for the unsaturated zone and the groundwater zone, coupled to a geographical informa-tion system. The system was applied to a water supply area located close to a major road south of Stockholm. Chloride was used as an indicator in determining the vulnerability for groundwater contamination from the road. The approach was useful to illustrate the dynamic change of chlo-ride concentrations both during the stage of continuous application and after the applications was terminated. A structure and content of a database for flow and transport modelling, based on hydrogeological environments, was outlined. An existing hydrogeological parameter database, HPAR at the Geological Survey of Sweden (SGU), was examined as a potential source of data for the new database. Values for some important parameters needed for groundwater modelling, such as hydraulic conductivity and effective porosity, were lacking in the three municipal HPAR databases that were studied. It was suggested that these data should be added, together with information on the hydrogeological environments, for all geographical positions of interest. Without such minimum information, the efficient use of modelling tools could not be expected.</p><p>Typical profiles of three common Swedish hydrogeological environments (sand deposits, glacial till and clay covered areas) were used to represent generic input data to model simulations in the unsaturated zone so that the importance of soil, vegetation type and groundwater levels on turn-over times of conservative contaminants transported by natural recharge could be examined. The same profiles were used to predict the penetration depth of accidental liquid spills that occur at the land surface level. In the case of contaminant transport by natural recharge, water storage in the soil profile and vegetation type played an important role for turnover times. For liquid spills, the hydraulic con-ductivity was found to be of major importance, while the water retention properties were of less importance. Modelling, together with available data sources, were successfully used to demon-strate the vulnerability of different environmental conditions.</p>

Magister Scientiae - MSc / The objectives of this study were: To review and understand flow and transport processes in unsaturated zones. In this study, particular emphasis is placed on understanding mechanisms that cause non-uniform (preferential) flow for two casestudies, namely the Cape Flats sandy environment and the Mpumalanga Highveld fractured rock environment. To evaluate the adequacy of models, in particular MACRO 5.0, in simulating flow and transport in the vadose zone, by making use of two case study sites (Cape Flats and Mpumalanga Highveld). Of particular importance is the evaluation of transfer coefficients to represent fluid and solute exchange between macropores and matrix. To run a sensitivity analysis with MACRO 5.0 in order determine which input model parameters are the most relevant in describing the effects of preferential flow in water and solute transport.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-03-17T17:03:39Z No. of bitstreams: 1 KellenMuradas.pdf: 10210667 bytes, checksum: 3f69e9c5b68e22ea3db001819c257ffb (MD5) / Made available in DSpace on 2015-03-17T17:03:39Z (GMT). No. of bitstreams: 1 KellenMuradas.pdf: 10210667 bytes, checksum: 3f69e9c5b68e22ea3db001819c257ffb (MD5) Previous issue date: 2011-01-01 / Nenhuma / O mapeamento de vulnerabilidade e a análise de risco de contaminação das águas subterrâneas são fundamentais para a orientação dos planos municipais de gerenciamento ambiental. Atualmente, novos critérios de enquadramento das águas subterrâneas são exigidos pela Resolução do CONAMA Nº396 /2008 e justificam o presente estudo. Os municípios escolhidos para o mapeamento de vulnerabilidade foram Portão e Estância Velha/RS, pois apresentam uma situação potencial de contaminação devido à atividade industrial dos setores coureiro-calçadista, plástico, tintas e solventes, além dos efluentes domésticos. Para a construção do mapa de vulnerabilidade, foi escolhido o método DRASTIC, acrônimo dos parâmetros a serem analisados: Depth water table, Recharge, Aquifer media, Soil type, Topography, Impact of vadose zone, Hydraulic Condutivity. Cada parâmetro é construído de forma dinâmica como um plano de informação no ambiente SIG a partir de características do meio que são espacializadas e, na fase final, integradas para gerar o mapa de vulnerabilidade em classes baixa, intermediária, alta e muito alta. A análise preliminar de risco é feita pela sobreposição deste mapa com o mapa de uso do solo. O Sistema Aquífero Guarani (SAG), na área de estudo, é representado pelos arenitos das formações Pirambóia e Botucatu, sendo parcialmente confinado pelo Aquífero Serra Geral e a recarga é favorecida pelo basalto densamente fraturado. A pouca profundidade dos níveis de água subterrânea e a litologia sedimentar são fatores decisivos para uma vulnerabilidade intermediária a alta e, devido à ação antrópica, os níveis de água subterrâneos sofreram depleção na área urbana. Os solos foram separados em domínios de acordo com a sua textura. O domínio Argissolo 1 apresenta-se espesso e com alto teor de finos no horizonte B, indicando um comportamento impermeabilizante. Os ensaios de infiltração e as camadas espessas de argila confirmam a baixa condutividade hidráulica dessa unidade pedológica, constituindo proteção natural do aquífero. Na área de estudo predomina o Argissolo 2, mais arenoso e, a presença restrita de argilominerais expansivos em superfície é fator atenuador da vulnerabilidade. O estudo de risco está diretamente relacionado à ocupação da área, que foi classificada em urbana, rural, silvicultura ou mata nativa. Estas classes, por ora, ocupam áreas de alta vulnerabilidade de contaminação do aquífero. Quanto à qualidade das águas subterrâneas, estes municípios possuem poucos dados disponíveis, não evidenciando o histórico de degradação ambiental na área, sendo um alerta para a necessidade de instalação de rede de poços de monitoramento. A eficiência do mapa de vulnerabilidade está associada à interdependência dos parâmetros envolvendo aspectos hidrogeológicos e geomorfológicos, tendo-se obtido 25% da área com alto grau de vulnerabilidade; 72,4% com grau intermediário e, apenas 2,6%, com baixo grau de vulnerabilidade à contaminação de águas subterrâneas. Dentre as recomendações, inclui-se priorizar o controle quantitativo e qualitativo das águas subterrâneas na área leste por constituir-se de alta vulnerabilidade com sobreposição da mancha urbana e atividades industriais. / The vulnerability mapping and risk analysis of groundwater contamination are essential to guide municipal plans of environmental management. Nowadays, new criteria to classify the groundwater quality are required by the CONAMA Resolution Nº 396/2008 which justify this work. The cities chosen for this study were Portão and Estância Velha/RS due to industrial activities like leather-footwear, plastics, paints and solvents, and domestic effluent in significant volume. The DRASTIC method was chosen to build the vulnerability map, which is a acronyms of the parameters to be analyzed: Depth water table, Recharge, Aquifer media, Soil type, Topography, Impact of vadose zone, Hydraulic Conductivity. Each parameter was built dynamically as an information layer in the GIS from characteristics of the environment that were spacialized and, in the final stage, integrated to generate vulnerability classes as low, intermediate, high and very high class. A preliminary risk analysis was done by overlapping of this map with the map of landuse. The Guarani Aquifer System (GAS) in the study area is composed by the sandstones from the Pirambóia and Botucatu Formations. The SAG is partially confined by the Serra Geral Aquifer when the recharge is favored by the densely fractured basalt. The shallow groundwater levels and sedimentary lithology are decisive factors for an intermediate to high vulnerability. However, due to human action, groundwater levels are depleted in urban areas. The soils were divided in domains according to their texture. The domain claysoil 1 shows thick layers with high content of clays in the B horizon, indicating an impermeable behavior. The infiltration tests and the thick layers of clay confirm the low hydraulic conductivity of this pedological unit, providing natural protection of the aquifer. However, in the study area dominates the claysoil 2, which is more sandy and whose low levels of expansive clay minerals in the surface decrease the vulnerability. The study of risk is directly related to the occupation of the area, which was classified as urban, rural, forestry or native forest. These classes occupy areas of high vulnerability to contamination of the aquifer. As the quality of groundwater, these cities have limited data available, not showing the history of environmental degradation in the area. This is an alert to the need of installation of properly distributed monitoring wells. The efficiency of the map is linked to the interdependence of parameters involving hydrogeological and geomorphological aspects, having been obtained a high degree of vulnerability to groundwater contamination in 25% of the area. An intermediate vulnerability was found in 72,4% of the area and a low degree in 2,6% of the area. In the recommendations, the qualitative and quantitative control of the groundwater in the east area was included because it constitutes high vulnerability with over urban use and industrial activities.

<p><font face="Helvetica"> <p align="left">The objectives of this study were:&nbsp / To review and understand flow and transport processes in unsaturated zones. In this study, particular emphasis is placed on understanding mechanisms that cause non-uniform (preferential) flow for two casestudies, namely the Cape Flats sandy environment and the Mpumalanga Highveld fractured rock environment.&nbsp / To evaluate the adequacy of models, in particular MACRO 5.0, in simulating flow and transport in the vadose zone, by making use of two case study sites (Cape Flats and Mpumalanga Highveld). Of particular importance is the evaluation of transfer coefficients to represent fluid and solute exchange between macropores and matrix.&nbsp / To run a sensitivity analysis with MACRO 5.0 in order determine which input model parameters are the most relevant in describing the effects of preferential flow in water and solute transport.</p> </font></p>

The focus of this thesis is on groundwater vulnerability assessment by process-based simulation models and data acquisition for these assessments. A modelling system for intrinsic groundwater vulnerability assessment in water supply areas was developed, consisting of flow- and transport models for the unsaturated zone and the groundwater zone, coupled to a geographical informa-tion system. The system was applied to a water supply area located close to a major road south of Stockholm. Chloride was used as an indicator in determining the vulnerability for groundwater contamination from the road. The approach was useful to illustrate the dynamic change of chlo-ride concentrations both during the stage of continuous application and after the applications was terminated. A structure and content of a database for flow and transport modelling, based on hydrogeological environments, was outlined. An existing hydrogeological parameter database, HPAR at the Geological Survey of Sweden (SGU), was examined as a potential source of data for the new database. Values for some important parameters needed for groundwater modelling, such as hydraulic conductivity and effective porosity, were lacking in the three municipal HPAR databases that were studied. It was suggested that these data should be added, together with information on the hydrogeological environments, for all geographical positions of interest. Without such minimum information, the efficient use of modelling tools could not be expected. Typical profiles of three common Swedish hydrogeological environments (sand deposits, glacial till and clay covered areas) were used to represent generic input data to model simulations in the unsaturated zone so that the importance of soil, vegetation type and groundwater levels on turn-over times of conservative contaminants transported by natural recharge could be examined. The same profiles were used to predict the penetration depth of accidental liquid spills that occur at the land surface level. In the case of contaminant transport by natural recharge, water storage in the soil profile and vegetation type played an important role for turnover times. For liquid spills, the hydraulic con-ductivity was found to be of major importance, while the water retention properties were of less importance. Modelling, together with available data sources, were successfully used to demon-strate the vulnerability of different environmental conditions. / QC 20101020

<p><font face="Helvetica"> <p align="left">The objectives of this study were:&nbsp / To review and understand flow and transport processes in unsaturated zones. In this study, particular emphasis is placed on understanding mechanisms that cause non-uniform (preferential) flow for two casestudies, namely the Cape Flats sandy environment and the Mpumalanga Highveld fractured rock environment.&nbsp / To evaluate the adequacy of models, in particular MACRO 5.0, in simulating flow and transport in the vadose zone, by making use of two case study sites (Cape Flats and Mpumalanga Highveld). Of particular importance is the evaluation of transfer coefficients to represent fluid and solute exchange between macropores and matrix.&nbsp / To run a sensitivity analysis with MACRO 5.0 in order determine which input model parameters are the most relevant in describing the effects of preferential flow in water and solute transport.</p> </font></p>