Dissertations / Theses on the topic 'Artificial Aquifer Recharge'

The main aim of the project is to investigate the feasibility of artificial recharge of the Bushmans River Mouth Aquifer in the Eastern Cape. The suggested method of recharge is through natural infiltration through a series of wetlands in the back dune area. The proposed site was the Klipfontein Vlei which is located just north of the Bushmans River Mouth. Artificial recharge is defined as augmenting the natural movement of surface water into underground formations by some method of construction, the spreading of water, or by artificially changing natural conditions. A variety of methods have been developed, including water spreading, recharging through pits and wells, and pumping to induce recharge from surface water bodies. The choice of a specific method is controlled by local topography, geology and soil conditions, and the quantity of water to be recharged and ultimate water usage. In special circumstances, land value, water quality, and climate play an important role. Artificial recharge is not a foreign concept to South Africa and this project is to test its feasibility in a back dune wetland area. Augering done in the study area revealed the dominance of sandy loam in the upper layers of the pans, loamy sand in the middle levels and the presence of some sand lenses in the lower reaches. Particle size analysis done by sieving and hydrometer test, showed a dominant 3f fraction. There was variation in modes in pan 1 from unimodal to bimodal to trimodal. Pan 2 showed no variation as all samples were unimodal and moderately well sorted. Infiltration tests were done by a double ring infiltrometer. These results showed that the infiltration rates of the pans became stable after 15 to 20 minutes, thus indicating that the soil had reached its saturation point. The resistivity surveys revealed a stepped water table. The inclination of the water is controlled by the predominately argillaceous horizons of the Bokkeveld Group. Based on the above results, it is recommended that the Klipfontein Vlei be used as an artificial recharge site.

Philosophiae Doctor - PhD
The study addressed the groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, the Omaruru River Delta Aquifer (Omdel Aquifer) was used as a case study. Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. Understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System is a pre-requisite for the management of groundwater supply in the Central Namib area (Namib Desert). For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge.

The thesis covers the investigation of the storm water runoff and artificial recharge components of the Atlantis Water Resource Management Scheme in the Southwestern Cape. The objective of the study was to obtain an in-depth knowledge of the process of artificial recharge of urban storm water runoff, in order to identify the most efficient recharge management strategy for the Atlantis aquifer. To achieve the objective it was necessary to first study the existing knowledge on urban storm water hydrology and artificial recharge by spreading, and to create a conceptual model of what might be expected. The study area was then investigated to examine how closely the actual situation was reflected by the conceptual model, enabling recommendations to be made for the sound management of the system. The stormwater runoff component was found to differ from most urban hydrological studies as a result of its large baseflow component. The sandy nature of the catchment, small percentage area of effective impervious surface, and high groundwater table resulted in the baseflow constituting more than 40% of the total storm water runoff and accounting for over 60% of the pollution load. The "first flush" effect established as a major source of pollution in other studies, was found to be of minor significance in this study area. The overall stormwater quality (excluding the noxious industrial baseflow) was found acceptable for artificial recharge within the study area, although the baseflow from the industrial sub-catchments showed the potential for being a major source of pollution in the future. The treated wastewater used for artificial recharge prior to 1987 was found to be unacceptable for recharge purposes. The treated industrial effluent should under no circumstances be recharged up-gradient of the Witzand well field. The treated domestic effluent although of a poorer quality than the resident Witzand well field groundwater could be recharged in order to boost recharge volumes and form a buffer against further intrusion by the poor quality groundwater from the Brakkefontein area. This would however only be acceptable if strict water quality control is maintained and recharge does not take place west of the present basin. The recharge basin was found to be well situated with respect to influencing the Witzand wellfield and maintaining a groundwater buffer against poor quality groundwater flow from the northeast towards the central area of the wellfield. Unfortunately the surrounding low-lying topography and sandy retaining walls have resulted in return flow and raised groundwater-levels. The raised groundwater mound does not comply with the conceptual model and together with the sandy nature of the unsaturated zone resulted in less effective purification during infiltration. The practice of letting large portions of the basin floor dry-out during summer was shown to be beneficial and the periodic cleaning of the deeper portions of the basin essential. The artificially recharged water was found to have influenced the upper portion of the aquifer well beyond the West Coast Road. The study of groundwater quality being a good method for tracing artificially recharged water. The groundwater quality has improved as a result of artificial recharge since the removal of treated wastewater from the recharge basin. The groundwater was (ii) found to be very responsive to the slightest changes in recharge basin water quality or/and quantity. Management of the recharge basin therefore had to be very much of a compromise between qualitative and quantitative approaches. The present approach of recharging all the stormwater runoff throughout the year providing the most efficient compromise under the present conditions. The study revealed that the most efficient recharge management strategy would be the recharge of treated domestic sewage effluent in the present recharge basin and all residential storm water runoff plus industrial "storm flow" stormwater runoff in a new recharge basin located northwest of the present basin. Strict water quality control must be maintained on the water discharged into the basins and an annual wet/dry cycle implemented within the basins to boost infiltration. The entire system should continue being monitored to safe guard the groundwater resource from pollution and over exploitation.

Technique émergente de gestion intégrée des ressources en eau pour résoudre des problèmes de gestion en zones arides, la Recharge Artificielle de Nappe RAN n'est pas appliquée aux aquifères carbonatés à cause des problèmes de karst. Son application au karst devrait cependant s'imposer. Cette thèse a analysé les conditions de recharge naturelle et artificielle, pour proposer une méthodologie d'Analyse de la faisabilité de Recharge Artificielle des aquifères Karstiques (ARAK) afin de définir des sites favorables à une recharge artificielle depuis la surface. 4 critères indépendants (Epikarst, Roche, Infiltration et Karst) sont considérés, indexés dans chaque maille à partir des données géologiques et topographiques, cartographiés selon une méthode d'indexation multicritère. L'indice de rechargeabilité intrinsèque, combinant ces critères, décrit l'aptitude de l'aquifère à être rechargé depuis sa surface, à l'échelle du système, puis à celle des sites les plus favorables. Un facteur de faisabilité technico-économique, mesurant les difficultés techniques et économiques d'une opération de recharge, est ensuite calculé à chaque site. Développée pour prendre en compte les aspects théoriques et pratiques rencontrés en identifiant les sites de RAN à partir de la surface, cette méthodologie devrait servir d'outil de gestion durable des ressources en eau karstique. La méthode ARAK a été testée sur l'aquifère karstique littoral de Damour, Liban, capté pour l'e au potable de Beyrouth, dont l'exploitation non contrôlée a conduit à une intrusion marine. Plusieurs sites de recharge à partir de la surface ont été identifiés. Mais le facteur technico-économique a révélé des difficultés techniques. La solution proposée consiste en une galerie horizontale, pour injecter l'eau de la rivière. Les établissements de l'eau considèrent qu'un tel projet offrira une solution intéressante pour satisfaire la demande en eau et combattre l'intrusion d'eau salée
Managed Aquifer Recharge MAR is an emerging sustainable technique used to solve water management problems. MAR presents great interest for karst aquifers, however known to present a high heterogeneity. MAR remains till date marginal in karst aquifers. Accordingly, the present work presents a methodology for Aquifer Rechargeability Assessment in Karst ARAK. The aim of ARAK is to determine the ability of a karst aquifer to be artificially recharged from its surface; and the best sites for implementing the recharge. Based on multi-criteria indexation analysis, ARAK considers 4 criteria: Epikarst, Rock, Infiltration, Karst. The criteria are indexed at each mesh of the 2 D grid domain, from geological and topographic data. ARAK computes the intrinsic rechargeability index, describing the rechargeability of a karst aquifer, on the regional scale, then on the identification of rechargeable sites. Subsequently, a feasibility factor, weighting the techn ical and economic difficulties of a recharge operation, is applied to the selected sites. The methodology, developed to reconcile the problems encountered to identify sites for MAR in karst, provides a useful tool to help water authorities to determine the potential of MAR in karst aquifers. ARAK was applied to Damour site (Lebanon). This coastal aquifer, source of water supply for Beirut, was salinated by its uncontrolled exploitation. A MAR system in Damour region should remediate to it. The four ARAK criteria were indexed and mapped. The final map showed that the aquifer is favorable to a recharge operation, and identified several potential rechargeable sites. However, the feasibility factor indicated that major difficulties hinder the use of infiltration ponds. The solution proposed consists of drilling a horizontal gallery for injecting river water. Water authorities consider that an aquifer recharge project could offer solutions for the shortage in water supply and the sea water intrusion

Thesis (M. Eng.)--Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 42-46).
Groundwater pumping from the Sparta aquifer in Union County, Arkansas, has long exceeded natural recharge, threatening the regional water supply. An alternative water-supply project, completed in 2004, now provides treated surfacewater to local industries. This conjunctive use of surface- and groundwater has allowed the Sparta aquifer to recover somewhat. Exploring further possibilities for Union County, the author has evaluated the potential of artificial recharge by well injection. A MODFLOW groundwater model was modified to simulate the aquifer's response. to artificial recharge. Results indicate that artificial recharge in this context is impractical. Injection increases hydraulic heads only locally, with the most improvement occurring where the injection is located in an existing cone of depression in El Dorado, Arkansas. Since groundwater withdrawals are already concentrated in this area, injection only reduces the net withdrawal rate. The same result could be achieved by reducing or substituting groundwater withdrawals directly, as has been observed since the completion of the alternative-supply project. The modeling results, along with analyses of surfacewater resources, suggest that continued and expanded conjunctive use is the most viable water-management strategy in Union County.
by Robert B. Sowby.
M.Eng.

The focus of this study was on recharge mechanisms and recharge estimation within the Table Mountain Group area. The study evaluated recharge processes and recharge estimation methods in the Table Mountain Group aquifer systems.

Many small communities depend on groundwater sources for drinking water and they often use septic tanks for their sewer system needs. However, nitrates and other pollutants from septic systems can percolate to the aquifers and deteriorate quality of the groundwater, threatening the public health. This study has developed a groundwater model using Visual MODFLOW for an aquifer that is used as a water supply source for the cities of Beaumont and Cherry Valley, California. Septic systems are the suspected major source of nitrate contamination of the aquifer. The model has been developed to clarify the extent of interactions between nitrate pollutants, infiltration and percolation from a recently established series of artificial recharge ponds, groundwater recharge from natural sources, and pumping activities to meet local water uses. The primary objective of this study is to evaluate alternative hydraulic solutions that would limit the movement of the contaminants and minimize the risk of affecting the pumping wells. The study attempts to identify the best way to recharge the aquifer and influence movement of the nitrates so that polluted waters may have lower nitrate concentrations in the future, rather than allowed to encroach on critical production wells or led away from production wells to become a problem for future generations or neighboring areas. The data needed to build the model, including geological logs, precipitation, evapotranspiration, well locations, pumping schedules, water levels, and nitrate concentrations have been obtained from the Beaumont Cherry Valley Water District. The model has been calibrated to simulate the observed groundwater levels and the extent of pollution corresponding to the historical pumping rates, recharge rates and climate. The calibrated model has been used to evaluate alternative hydraulic solutions that would either localize the nitrate pollution thus limiting the impact on public welfare, or remove the nitrate pollution for potential treatment and remediation on the surface. The study results show that increased pumping of production wells or strategic placement of additional artificial recharge may reduce the concentrations of nitrate in the Beaumont Basin.

En ville, les systèmes de récupération et d'infiltration des eaux pluviales dans le sous-sol ont pour conséquence d'augmenter la connectivité hydrologique entre la surface et la nappe phréatique. Ces pratiques d'infiltration produisent de nombreuses perturbations physico-chimiques au niveau de la nappe (ex. augmentation des variations thermiques, baisse des concentrations en oxygène dissous, enrichissement de la nappe en matière organique dissoute) mais les conséquences sur le compartiment microbien restent peu connues. L'objectif principal de la thèse est de déterminer les effets de l'infiltration des eaux pluviales sur les communautés microbiennes des nappes phréatiques, aussi bien en termes d'abondance, d'activités que de diversité génétique bactérienne. En se basant sur les changements environnementaux associés à l'infiltration des eaux pluviales et l'analyse des communautés bactériennes, un objectif fondamental est d'évaluer l'importance des phénomènes de dispersion (ex. transferts) et de sélection par des facteurs abiotiques (ex. disponibilité des ressources nutritives) sur les assemblages bactériens au sein des nappes phréatiques. Ces travaux ont été axés sur des expérimentations de terrain utilisant deux approches d'échantillonnage : une méthode active (prélèvements d'eau) et une méthode passive (incubation de substrats artificiels). La description des communautés a été effectuée par une méthode de séquençage de nouvelle génération (i.e. Illumina MiSeq) en se basant sur le gène rrs. Les résultats de ce travail mettent en avant une influence significative des pratiques d'infiltration sur les bactériomes d'un aquifère. En effet, le développement, les activités et la diversité des micro-organismes retrouvés dans la nappe ont été stimulés significativement par l'enrichissement en carbone organique dissous biodégradable engendré par ces pratiques. Néanmoins, cet impact est fortement réduit dans les systèmes étudiés où la zone non saturée est épaisse (> 10 m) et agit comme un filtre physique, chimique et biologique efficace entre le bassin d'infiltration et l'aquifère. Les faibles similarités entre les structures génétiques des bactériomes des eaux d'infiltration et dans la nappe indiquent que la zone non saturée joue un rôle efficace sur la rétention des bactéries dans les systèmes étudiés. En conclusion, cette thèse constitue la première étude d'envergure visant à quantifier la réponse du compartiment microbien des aquifères à des perturbations engendrées par l'infiltration des eaux pluviales en milieu urbain. Elle ouvre aussi de nouvelles perspectives sur les méthodes et outils d'évaluation de la qualité des nappes phréatiques
In urban area, managed aquifer recharge (MAR) systems raises hydrological connectivity between surface and groundwater. These infiltration practices are the cause of many disturbances in groundwaters (e.g. increase of thermal variations, decrease of dissolved oxygen or enrichment in organic matter) but associated consequences on microbial compartment remains unclear. The main aim of the thesis is to determine the effects of stormwater runoff infiltration on microbial communities of groundwater, in terms of abundance, activities and bacterial diversity. Based on environmental changes associated to MAR practices and bacterial community analyses, a fundamental question is to assess the importance of dispersal (e.g. transfers) and selection by abiotic factors (e.g. nutrients availability) on groundwater communities assemblage. This study is based on field experiments with two complementary strategies of sampling: an active one (i.e. groundwater sampling) and a passive one (incubation of artificial substrate). Communities’ description was made by next-generation sequencing (i.e. Illumina MiSeq) of rrs gene. The results showed a significant influence of MAR practices on microbial communities. Growth, activities and diversity of groundwater micro-organisms were mainly stimulated by biodegradable dissolved organic carbon enrichment associated to MAR practices. Nonetheless, this impact was reduced in systems where the vadose zone is thick (> 10 m) and acts as a physical, chemical and biological filter between the infiltration basin and the aquifer. Low similarities between bacterial communities of infiltration waters and bacterial communities of groundwaters reveal that vadose zone is effective on the retention of bacteria in studied systems. To conclude, this thesis constitutes the first major study that aimed to quantify microbial compartment response to disturbances caused by MAR practices in urban area. It also opens new perspectives on assessment tool for groundwater quality

Die vorliegende Arbeit umfasst im ersten Teil eine Literaturrecherche zu Aquifer Storage and Recovery (ASR) im Allgemeinen und den Einfluss physikalisch-chemischer Prozesse auf ASR. Aus dieser konnte abgeleitet werden, dass durch standortbedingte Untergrundeigenschaften stark unterschiedliche physikalische und chemische Prozesse ablaufen und eine eindeutige Vorhersage zum Verhalten und zur Effizienz von ASR an einem neuen oder bereits genutzten Standort ohne spezifische Informationen nicht möglich ist. Des Weiteren wurde eine Literaturstudie zum Einfluss der transversalen Dispersivität, als Maß für die Vermischung von transportierten Stoffen quer zu einer (natürlichen) Fließrichtung, auf den (reaktiven) Transport durchgeführt. Letztlich wurde im Rahmen einer betreuten Masterarbeit (M. Sc. Chang Liu) eine Bewertung aus der Literatur entnommener transversaler Dispersivitäten durchgeführt. In den weiteren Teilen der Arbeit wurden Fallstudien mit unterschiedlichen Fragestellungen für die Planung und den Betrieb von künstlichen Grundwasseranreicherungen und speziell ASR numerisch modelliert und bewertet. Zuerst wurden numerische Simulationen zum konservativen Transport am Testfeld „Lauswiesen“, Tübingen, Baden-Württemberg durchgeführt. Diese beinhalteten über Direct-Push(DP)-Erkundungsmethoden gewonnene Informationen zur Untergrundstruktur. Die Ergebnisse zeigen, dass zur Vorhersage des standortspezifischen Transports in den „Lauswiesen“ und für vergleichbare hydraulische Situationen, auch in Hinsicht auf ASR, deterministische hydrogeologische Einheiten und ihre situationsgerechte Berücksichtigung in numerischen Modellen höchst relevant sind. Aufbauend auf den genannten Ergebnissen wurde eine Masterarbeit durch Herrn M. Sc. Tsegaye Abera Sereche durchgeführt. Diese Masterarbeit zeigte für diesen Fall erneut die hohe Relevanz deterministischer Strukturen gegenüber kleinskaligen, dreidimensionalen Heterogenitäten für ASR. Weiterführende numerische Simulationen zu einem möglichen ASR-Feldtest am Standort „Lauswiesen“ ergaben, dass dieser unter den gegebenen Untergrundbedingungen nur bei Abweichungen von einem vertretbaren Konzept für einen Ein-Brunnen-Test, z. B. bei sehr großen Infiltrationsmengen, oder durch Umwandlung in einen Zwei-Brunnen-Test durchführbar ist. Während dieser Arbeit wurden gemeinsame Forschungsarbeiten mit dem Kansas Geological Survey, Kansas, USA durchgeführt, welche die Bewertung der Verwendbarkeit von DP-Brunnen als alternative Infiltrationsmethode zu Oberflächenmethoden beinhalteten. Als Teil der gemeinsamen Arbeiten wurde im Rahmen der vorliegenden Arbeit eine synthetisierte, numerische Bewertung der neuen DP-Infiltrationsbrunnen sowie einen Vergleich mit einer herkömmlichen Oberflächeninfiltrationsmethode übernommen. Im Einklang mit der Zielstellung der Arbeit wurde ebenfalls eine numerische Bewertung natürlicher und anthropogener Heterogenitäten auf die Infiltration durchgeführt. Aus den Ergebnissen konnten für die neue Infiltrationsmethode signifikante Vorteile abgeleitet werden. Weitere numerische Modellierungen wurden durchgeführt, um die wesentlichen Ergebnisse auf einen Feldstandort in der Südlichen Steiermark, Österreich, anzuwenden, welcher: a) bereits ein horizontales Versickerungssystem besitzt, b) weitere Systeme erhalten soll und c) letztlich eine besondere Herausforderung für vertikale Versickerungssysteme darstellt. Die Modellierung des vorhandenen Systems zeigt die hohe Komplexität der Infiltrationsprozesse. Jedoch konnten hydraulische Parameter bestätigt und in weitere planerische Simulationen zu Verwendung von DP-basierten Infiltrationsbrunnen eingefügt werden. Diese zeigen, dass ein Brunnenfeld am Standort auf relativ geringem Raum installiert werden kann. Zusätzlich zeigt ein Feldversuch an einem weiteren Standort (Pirna, Sachsen), dass hohe Infiltrationsraten unter Nutzung von DP-Brunnen möglich sind
The works presented in the thesis include in the first part a literature research on Aquifer Storage and Recovery (ASR) in general and the impacts of different physico-chemical processes on ASR. This research concludes that site-specific subsurface conditions lead to varying physical and chemical processes and that a conclusive prediction of function and efficiency of ASR at any site, in-operation or new site design, is not possible without site-specific information. Additionally, a literature study was conducted that focused on the impacts of transverse dispersivity, as a measure for mixing of transported species perpendicular to the (natural) flow direction, on (reactive) transport. Finally, evaluation of transverse dispersivity data available in the literature was performed, which included a supervision of a master thesis (of M. Sc. Chang Liu). Numerical simulations of case studies for different questions of planning and operation of artificial recharge systems and more specifically ASR were realized for the other parts of the thesis. The first evaluated case was the “Lauswiesen” test site, Tübingen, Baden-Wuerttemberg. This study used new insights into the subsurface structure gained by Direct-Push(DP) exploration methods. The results obtained show that for further works at the site and for comparable hydraulic conditions, also in the view of ASR, deterministic hydrogeological subunits and their consideration in numerical models are critical for prediction of site-specific transport. Based on the previous findings, a master thesis was conducted by M. Sc. Tsegaye Abera Sereche. The master thesis yet again revealed for this case the high relevance of deterministic subunits compared to small-scale, three-dimensional heterogeneities for ASR. Further, numerical simulations of a possible ASR field test at “Lauswiesen” site showed that under the prevailing subsurface conditions, a field test can only be realized when the set-up of a single-well-test is impracticably changed, by e.g. very high infiltration volumes, or by transformation into a two-well-test. During the thesis joint research works were performed with the Kansas Geological Survey, Kansas, USA, which contained the evaluation of the applicability of DP wells as an alternative to surface infiltration methods. As part of the joint work, this thesis presents a synthesized numerical evaluation of the new DP well infiltration as well as a comparison to a common surface infiltration system. Furthermore, in accordance with the main objective of the work, numerical evaluation of natural and anthropogenic heterogeneities was performed. The results concluded the advantages for the DP wells for infiltration process. Further numerical models were implemented to convey the important results to a field site at Southern Styria, Austria, where: a) an existing infiltration system is already in operation, b) further infiltration systems are planned and c) the subsurface conditions are rather challenging for vertical infiltration systems. Modeling of the existent system revealed the high complexity of the infiltration processes. However, hydraulic parameters could be verified and included into planning simulations for DP-based infiltration wells. The findings show, that a well field can be installed at a comparably small land. Additionally, a field test at a further test site (Pirna, Sachsen) indicates that high infiltrations rates are possible when DP wells are used

South Africa has been facing challenges in both its energy and water sectors over the past few years. They are heavily dependent on each other and a better understanding of the linkages between the two sectors is crucial for sustainable development and planning in both sectors. While the water-energy nexus has been widely explored in developed countries, there is a limited amount of literature found on the significance of the nexus in South Africa. With the current critical drought in the region, alternative water sources are being considered by the City of Cape Town including seawater desalination, water re-use and abstraction of groundwater, to increase potable water supplies. The Cape Flats Aquifer represents a significant water resource for Cape Town and its yield can be further augmented by using artificial recharge with stormwater. Due to the location and water quality of the resource, several possible approaches have been identified for its exploitation. This study investigates quantitatively the energy implications of the three selected approaches in order to exploit the Cape Flats Aquifer as an alternative water source for Cape Town and further provides the potential carbon emissions from their respective energy usages. The three approaches consist of a Centralised Approach to treat the abstracted water for potable uses at two existing Water Treatment Plants (Blackheath and Faure); a Decentralised Approach to supply neighbouring suburbs with minimally treated water for non-potable uses through four proposed treatment plants and a Desalination Approach to treat brackish groundwater to potable quality at a proposed desalination plant. The energy implications of the approaches were evaluated using both direct energy usage during the abstraction, conveyance and treatment stages and the embodied energy of the consumables used during the treatment processes. These were then used to compare the shares of direct electricity intensities and embodied energy intensities of the alternatives at each stage to determine their viability. The individual stages' and overall energy intensities were quantified in form of the total energy required to produce a kl of treated water. The minimum energy required to abstract and convey the water was estimated using basic hydraulic principles. The energy usage at treatment plant levels was computed using the installed electrical capacities at the two existing water treatments for the Centralised Approach while the Decentralised Approach's demand was estimated by determining the treatment processes required to produce non-potable water, which is fit for usage. Energy requirements at the desalination plant were estimated using the salinity levels of the brackish groundwater and target salinity concentration of the treated water. The energy intensities of the approaches were then used as a basis to calculate the current and future electricity costs and their associated carbon footprints using the CSIR (2016) least cost scenario and the IRP (2016) base case future electricity mixes, as the higher and lower threshold for electricity generation costs and carbon emissions. The study found that the electricity intensities of all three alternatives depended significantly on the spatial layout of their respective systems, that is, the topography, distance and extent of their transmission networks. However, the embodied energy intensity of the Centralised alternative was found to be comparable to its electricity intensity, since more chemicals were to purify the water to potable levels. The Decentralised Approach's extensive pumped transmission networks contributed the most to its electricity intensity during the treatment process. The Desalination option was found to be the most energy intensive alternative, with energy intensities ranging from 7.41 to 9.62 MJ/kl, of all three options (1.16 to 1.57 MJ/kl for the Centralised Approach and 3.57 to 7.31 MJ/kl for the Decentralised Approach) and had the highest costs and emissions intensities, mostly caused by the country's coal intensive electricity mix. The Centralised option was found to be the least energy and carbon intensive of the three options and the most viable approach investigated. Desalination, nonetheless, can still considered as an alternative, given the issue of water scarcity, to increase water supplies. Despite its high energy demands, its carbon footprint could potentially decrease with a larger uptake of renewable energy technologies as sources of electricity. The importance of holistic planning across sectors was brought out quantitatively by using current and future water and energy mixes, providing valuable insights on the water-energy nexus, in this study.

[Truncated abstract] Managed Aquifer Recharge (MAR) is a technique that can be used to capture and store water in aquifers for later reuse. This method recycles water that would normally be lost or discarded to the environment. MAR has been observed to have the potential for improving the quality of recharged water through a combination of physical, chemical and biological processes. The aim of this study was to investigate the changes in groundwater microbial population structure during MAR and the major influences that drive these population changes. Biogeochemical MAR studies have the potential to assist in the improved prediction of the removal of contaminants such as nutrients, pathogens and trace organics from the recharged water. Biological clogging during recharge also has the potential to overwhelm an aquifers ability to process wastewater thus reducing the hydraulic conductivity of the aquifer. Therefore further research into the spatial and temporal biogeochemical processes that occur during MAR is required. The geochemical and microbial population dynamics of two contrasting MAR techniques were investigated at two different geographical locations (Perth, Western Australia and Adelaide, South Australia). These MAR sites contained aquifers of dissimilar properties that were recharged with wastewater that contrasted in water quality. The Perth MAR site received secondary treated effluent which continuously infiltrated the unsaturated zone into an unconfined aquifer aided by infiltration galleries. Reclaimed water was extracted from a well at distance from the infiltration gallery. ... Notably the background and recovered water was most dissimilar in microbial and chemical population structure to that described for the infiltration gallery and injection well. Microbial and chemical evidence suggested that the background and extraction well groundwater were unaffected by plume migration. These results suggested that extraction well groundwater was similar in quality to that of ambient groundwater. Significant geochemical and microbial changes of secondary treated effluent during infiltration and lateral movement through aquifer were implicated in addition to the forced hydraulic gradient created from extracting fives time the volume of infiltrating wastewater. This study demonstrated that microbial populations and the geochemical processes associated with MAR can be studied and compared. Multivariate statistical methodology greatly simplified a vast array of dynamic biogeochemical information that could be dissected for meaningful interpretation over distance and time. The study evaluated the major biogeochemical influences which resulted in microbial and geochemical changes where it was noted that microbial populations were more dynamic than geochemical variation over time. Additionally biogeochemical comparative analysis indicated that microbial populations could change in population structure before a shift in aquifer geochemistry was detected. It is anticipated that the results from this study will benefit further research into the biogeochemical processes involved in water quality changes (e.g. nutrient removal, pathogen decay and biodegradation of trace organics) as well as controlling biological clogging of MAR schemes.

In der vorliegenden Dissertation sollten die hydrogeochemischen Prozesse herausgearbeitet werden, die für die Wasserqualitätsänderung während eines ASR Experiments in Bolivar, Südaustralien und während der Versickerung in einem künstlichen Grundwasseranreicherungsbecken in Berlin von Bedeutung waren. Reaktive Stofftransportmodellierung des ASR Experiments in Bolivar, Südaustralien zeigte, dass die hydrochemischen Veränderungen in der direkten Umgebung des Injektionsbrunnens während der Speicherphase nur durch rapide Änderungen der Sauerstoff- und Nitrat reduzierenden Bakterienmasse erklärt werden können. Die hydrochemischen Veränderungen in größerer Distanz zum Injektionsbrunnen wurden überwiegend durch Ionenaustauschprozesse und Kalzitlösung verursacht. Geochemische und hydraulische Messungen unter einem Sickerbecken in Berlin zeigten, dass die beobachteten geochemischen Änderungen im Sickerwasser mit den periodisch auftretenden wassergesättigten/wasserungesättigen Bedingungen unter dem Becken einhergehen. Während der ungesättigten Periode wird Luft unter das Becken gezogen und führt zur plötzlichen Reoxidierung von bereits in der gesättigten Periode gebildeten Eisensulfiden und zur beschleunigten Mineralisation von sedimentärem organischem Kohlenstoff. Reaktive Stofftransportmodellierung auf größerer Skale zeigte, dass allein die saisonalen Temperaturunterschiede im Infiltrationswasser für die beobachtete zeitliche und räumliche Dynamik der Redoxzonen im weiteren Abstrom des Sickerbeckens verantwortlich sind. Das Abbauverhalten der Arzneimittelsubstanz Phenazon hängt ausschließlich von der Verfügbarkeit von gelöstem Sauerstoff und damit indirekt von der Wassertemperatur im Aquifer ab. In der vorliegenden Arbeit wird deutlich, dass ein adäquates Verständnis der wasserqualitätsändernden Prozesse in künstlichen Anreicherungsystemen nur dann erreicht werden kann wenn Strömung, Transport und reaktive Prozesse, im Feld als auch in der Modellierung, simultan betrachtet werden.
In this thesis, three major studies were carried out in order to understand the key factors controlling the water quality changes that occurred during a reclaimed water Aquifer Storage and Recovery (ASR) experiment at Bolivar, South Australia and during ponded infiltration in Berlin, Germany. Multi-component reactive transport modelling of the ASR experiment suggested that during the storage phase, dynamic changes in bacterial mass have a significant influence on the local geochemistry in the vicinity of the injection well. Water quality changes further away from the injection well were mainly driven by ion exchange and calcite dissolution. Geochemical and hydraulic measurements below an artificial recharge pond in Berlin, Germany, showed that the observed dynamic changes of the hydrochemistry within the seepage water are strongly linked to the periodic saturated/unsaturated hydraulic conditions below the pond. During unsaturated conditions, atmospheric oxygen penetrates from the pond margins to the centre below the pond, leading to (i) a sudden re-oxidation of sulphide minerals that have formed previously during saturated conditions and (ii) an enhanced mineralisation of sedimentary particulate organic carbon. Reactive transport modelling showed that at larger scale, seasonal temperature changes of the infiltration water are the key control for the observed temporal and spatial redox dynamics further downstream the recharge pond. Moreover, the degradation behaviour of the pharmaceutically residue phenazone solely depends on the availability of dissolved oxygen, and thus indirectly on the water temperature within the aquifer. Overall this thesis shows that a sound understanding and analysis of the key processes affecting the water quality changes during artificial recharge of groundwater could only be achieved when flow, transport and reactive processes are considered simultaneously, both in the field and during modelling.

En el acuífero de la Plana de Castellón (área de La Rambleta) se ha implantado, como medida de lucha contra la intrusión marina, una actuación de recarga artificial de acuíferos. La caracterización de los efectos y de los procesos que tienen lugar en el acuífero como consecuencia de la recarga artificial se ha realizado con la utilización conjunta de técnicas hidrogeoquímicas y geofísicas. Las velocidades de flujo se han calculado a partir de las variaciones de la CE, de los cloruros y nitratos, y de los isótopos estables del agua. Los procesos hidrogeoquímicos se han identificado y cuantificado a partir de las concentraciones de los iones mayoritarios y sus deltas iónicos. La distribución del agua de recarga en el acuífero se ha estudiado a partir de tomografías de resistividad eléctrica (ERT), obteniéndose una triple relación entre valores de ER, litología de los sedimentos y CE del agua subterránea.
A managed aquifer recharge (MAR) has been implemented as a measure to face marine intrusion in the southern half of the Plana de Castellón aquifer (​​Rambleta area). The characterization of the effects and processes that occur in the aquifer as a consequence of artificial recharge has been carried out from the combination of hydrochemical and geophysical techniques. The flow rates have been calculated from the variations of the EC, chlorides and nitrates, and stable isotopes of water. The hydrogeochemical processes have been identified and quantified from the concentrations of the major ions and their ionic deltas. The distribution of recharge water in the aquifer has been studied from electrical resistivity tomography (ERT), obtaining a triple relationship between ER values, sediment lithology and groundwater EC. This multiparametric treatment has allowed to define the shape and extension of the recharge plume.

Les réseaux trophiques jouent un rôle primordial dans la régulation des flux de matière et d'énergie au sein des écosystèmes. Dans le cadre des pratiques de recharge artificielle des aquifères, les biocénoses souterraines sont pleinement sollicitées et leur capacité à dégrader les flux de matière organique de surface conditionne le maintien de la qualité des eaux souterraines. L'objectif de ce travail est de déterminer l'influence d'une augmentation des flux de carbone organique dissous sur l'intensité des interactions trophiques entre les communautés microbiennes et les assemblages d'invertébrés au toit des nappes phréatiques rechargées artificiellement avec des eaux de ruissellement pluvial. A travers une approche expérimentale de terrain et de laboratoire, ce travail permet d'évaluer l'intensité des relations existant entre les flux de carbone organique dissous, les conditions environnementales, l'activité et la diversité de communautés microbiennes et l'abondance des communautés d'invertébrés.

Dans un champ captant, comme celui qui alimente l'agglomération lyonnaise, le fonctionnement de chaque « objet » (bassins d'infiltration, puits, rivières, nappe, zone non saturée) et leurs interactions sont complexes et mal connus. Dans un premier temps, une série d'essais d'infiltration à différentes échelles dans un bassin artificiel de réalimentation a permis de mieux appréhender le fonctionnement de cet ouvrage et de chiffrer les paramètres hydrodynamiques de la zone non saturée. Les résultats des interprétations par méthodes numériques fondées sur l'équation de Richards ont montré que les flux infiltrés dans les bassins dépendent principalement de la conductivité hydraulique à saturation d'une couche située directement sous le sable calibré couvrant le fond du bassin, identifiée comme étant moins perméable que la nappe. Cette couche conditionne l'existence d'une zone non saturée. La réalisation d'essais de pompage dans l'aquifère sur les forages d'exploitation et sur un dispositif spécialement mis en place durant ce travail a permis de déterminer les paramètres hydrodynamiques de la nappe. Une analyse des observations et une modélisation conceptuelle en 2D, puis en 3D ont permis d'identifier les mécanismes prépondérants (stratifications, apports et prélèvements) et de simuler correctement à la fois les flux infiltrés dans un des bassins d'infiltration et la remontée de la nappe. A l'échelle d'un bassin, les flux infiltrés sont variables dans le temps, ils dépendent de l'état de colmatage de la surface d'infiltration mais également de la température de l'eau infiltrée et de l'état hydrique initial du sol sous le bassin. Les analyses de sensibilité réalisées avec les modèles mis en place indiquent que la conductivité hydraulique à saturation de l'aquifère, mais également la proximité des conditions aux limites imposées dans la nappe (les rivières et les puits de pompage) influencent de manière prépondérante la remontée de la nappe. Une modélisation 3D d'un autre secteur du champ captant comprenant deux bassins d'infiltration, deux bras de rivière ainsi que des puits de pompage a été réalisée. La condition à la limite imposée sur les rivières est du troisième type en accord avec l'observation d'un sous-écoulement en nappe. Les échanges nappe/rivières sont calés sur des observations à partir d'une chronique de propagation d'une onde de crue dans la nappe. Des piézomètres en flûte de pan, spécifiquement implantés à proximité d'un bassin, ont permis d'observer des différences de charge hydraulique fortes à différents niveaux de l'aquifère lorsque le bassin d'infiltration est en eau. La modélisation 3D est conforme à ces observations. Elle a confirmé l'importance du rôle d'une hétérogénéité de type argilo-sableuse (de conductivité hydraulique à saturation inférieure aux autres lithologies présentes dans l'aquifère) dans les écoulements (direction et flux). Le modèle développé représente correctement les flux infiltrés via les bassins ainsi que les fluctuations de la piézométrie de la nappe. Il permet de vérifier l'inversion des écoulements par rapport aux infiltrations de la rivière, d'identifier les puits alimentés par les bassins d'infiltration et également de mettre en évidence les flux de nappe passant sous la rivière
In a well field of the Lyon metropolitan area, designed for drinking water supply, behaviour of each object (infiltration basins, wells, rivers, aquifer, and unsaturated zone) and their interactions are complex and not well-known. As a first step, infiltration tests at different spatial scales in one artificial basin were performed to better understand the basin operation and to estimate the hydrodynamic parameters of the unsaturated zone. Results of interpretation, using numerical methods based on Richards equation, reveal that infiltrated basin fluxes mainly depend on saturated hydraulic conductivity of a layer located just below the calibrated sand layer that cover the basin bottom. Indeed this layer has been estimated to be less permeable than the aquifer, which allows the existence of the unsaturated zone below. Pumping tests in the groundwater have been performed using production wells and a well specially implemented during this thesis work in order to estimate aquifer hydrodynamic parameters. Observations analysis and a conceptual modelling, in 2D and then in 3D, lead to a better understanding of the controlling mechanisms (stratification, input and output) and to simulate both basin infiltration rates and water table rise. Considering the whole basin scale, input fluxes are transient, related to the clogging statement of the infiltration area but also to the temperature of inflow water and the initial statement of the soil just below the basin. Sensibility analyses using the models highlight that the amount of the water table rise is mainly influenced by the aquifer saturated hydraulic conductivity and also by the location of imposed boundaries in the aquifer (rivers and pumping wells). The model properly accounts basin inflow fluxes and water table fluctuations. The model is able to verify if flows are reversed in relation to river exchanges, if wells are fed by infiltration basins and it highlights aquifer flows below the river. A 3D modelling has been realised in another area of the well field, comprising two infiltration basins, two river arms and pumping wells. In agreement with underflow in the aquifer, rivers are imposed in the model as third kind boundary conditions. Aquifer and river exchanges are calibrated with observed data of one aquifer flood-wave propagation. Significant differences of hydraulic heads have been observed at different depths of the aquifer using panpipes piezometers, specifically implemented, close to one infiltration basin. Theses differences are closely related to basin operation. These observations are properly calculated by the 3D model. Using the model, the effect of one sandy-clay heterogeneous layer (whose saturated hydraulic conductivity is lower than the ones of other aquifer lithologies) on aquifer flows (direction and flux) is notable. The model properly accounts basin inflow fluxes and water table fluctuations. The model is able to verify if flows are reversed in relation to river exchanges, if wells are fed by infiltration basins and it highlights aquifer flow below the river

La Recàrrega Artificial d'aqüífers és una tècnica extremadamente poderosa per optimitzar la gestió dels recursos hídrics. De cara a eliminar actituds escèptiques respecte a la seva aplicabilitat en nombroses situacions, és essencial adquirir més coneixements sobre els conceptes quantitatius més importants. Un tema crític és el de la minimització de la colmatació en dispositius de recàrrega. Atesa la extraòrdinaria importància d'aquest problema, es va efectuar una intensa recerca bibliogràfica que permetés determinar els processos bàsics que tenen lloc en la colmatació de plantes de recàrrega. Això, juntament amb la informació de tipus tecnológic subministrada per gestors de plantes de recàrrega, ha permès proposar un model matemàtic conceptual que integra els processos principals: retenció de partícules en suspensió portades per l'aigua de recàrrega, precipitació de minerals, creixement bacterià, generació de gas y compactació. Amb l'ajuda dels codis ja existents, l'esmentat model fou posteriorment incorporat a un programa d'elements finits tridimensionals que és capaç de tractar els cinc processos citats. El programa ha estat aplicat a tres casos de laboratori i a un experiment de camp amb el fi d'establir la validesa del marc conceptual adoptat.

Aquesta tesi descriu els aspectes principals del model, els seus fonaments teòrics, la implementació numèrica i l'aplicació als exemples citats. La varietat de condicions simulades i els resultats aconseguits confirmen que el programa pot reproduir de forma satisfactòria una ampli ventall de problemes de colmatació, entre les quals s'inclouen sistemes superficials (bassas) i profunds (pous), flux radial i vertical, transport reactiu multicomponent, i d'altres. Això demostra la utilitat del programa per integrar dades de naturalesa completament diferente. A pesar de les limitacions inherents a tota formulació matemàtica, la modelació integrada proporciona estimacions quantitatives del potencial colmatant. Consegüentment, pot ser considerada com a una eina bàsica per al disseny i gestió de plantes de recàrrega i, eventualment, amb un fi predictiu.
La Recarga Artificial de acuíferos es una técnica extremadamente poderosa para optimizar la gestión de los recursos hídricos. De cara a eliminar actitudes escépticas respecto a su aplicabilidad en numerosas situaciones, es esencial adquirir más conocimientos sobre los conceptos cuantitativos más importantes. Un tema crítico es el de la minimización de la colmatación en dispositivos de recarga. Dada la extraordinaria importancia de este problema, se efectuó una intensa búsqueda bibliográfica que permitiera determinar los procesos básicos que tienen lugar en la colmatación de plantas de recarga. Esto, junto con la información de tipo tecnológico suministrada por gestores de plantas de recarga, ha permitido proponer un modelo matemático conceptual que integra los procesos principales: retención de partículas en suspensión en el agua de recarga, precipitación de minerales, crecimiento bacteriano, generación de gas y compactación. Con la ayuda de códigos ya existentes, dicho modelo fue posteriormente incorporado en un programa de elementos finitos tridimensional que es capaz de tratar los cinco procesos citados. El programa ha sido aplicado a tres casos de laboratorio y a un experimento de campo con el fin de establecer la validez del marco conceptual adoptado.

Esta tesis describe los aspectos principales del modelo, sus fundamentos teóricos, la implementación numérica y la aplicación a los ejemplos citados. La variedad de condiciones simuladas y los resultados logrados confirman que el programa puede reproducir de forma satisfactoria una amplia gama de problemas de colmatación, entre las que se incluyen sistemas superficiales (balsas) y profundos (pozos), flujo radial y vertical, transporte reactivo multicomponente, y otros. Esto demuestra la utilidad del programa para integrar datos de naturaleza completamente diferente. A pesar de las limitaciones inherentes a toda formulación matemática, la modelación integrada proporciona estimaciones cuantitativas del potencial colmatante. Por consiguiente, puede ser considerada como una herramienta básica de cara al diseño y gestión de plantas de recarga y, eventualmente, de cara a la predicción.
Artificial Recharge of groundwater is an extremely powerful technique to optimise the management of water resources. In order to eliminate sceptical misconceptions concerning its applicability to numerous situations, it is essential to gain insight into the fundamental quantitative concepts. A critical point is the minimisation of clogging of the recharge device. Given the extraordinary importance of this problem, an intensive bibliographic research was conducted to determine the basic processes underlying the clogging of recharge plants. This, in combination with technological information supplied by Artificial Recharge operators, allowed to propose a conceptual mathematical model that could integrate the main processes. Attachment of suspended solids carried by recharge water, mineral precipitation, bacterial growth, gas binding and compaction of the upper soil layer were found to be determinant in clogging development. Based on existing investigation codes, such model was implemented into a three-dimensional finite element code that is able to cope with the referred mechanisms. The code was applied to three laboratory cases and to one field experiment in order to assess the validity of the adopted framework.

This thesis includes the main concepts of the model, its theoretical background, numerical implementation and the application to the referred cases. The variety of simulated conditions and the results achieved with the model confirm that the code can reproduce successfully a wide range of clogging problems, including surface (basins) and deep (wells) systems, vertical and radial flow, multiphase transport and other options. This demonstrates the usefulness of the code to integrate data which are completely different in nature. In spite of the limitations inherent to all mathematical formulations, integrated modelling provides quantitative estimates of the clogging potential. Consequently, can be considered as a basic tool for design and management of recharge plants, and, eventually, for predictive purposes.

Artificial recharge of aquifers through infiltration basins (AR) improves water quality and in- creases groundwater resources, which make of it an appropriate technique for the renaturalization of waters affected directly or indirectly by wastewater effluents. Emerging organic compounds (EOCs), typically present in such waters, are mainly reduced during AR by sorption and biotrans- formation. We installed a reactive barrier in an infiltration basin (5000 m2) to enhance the removal of EOCs in the recharge water. The barrier consisted of sand, vegetable compost, iron oxide and clay. Vegetable compost was aimed at: 1) release organic carbon to be used as a carbon source by the microbial community thus promoting the generation of diverse redox conditions, and 2) to adsorb neutral EOCs. Clay and iron oxides were aimed at increasing sorption sites for cationic and anionic EOCs, respectively. Field application of such a design was tested by comparing the redox indicators and behavior of EOCs prior and after the installation of the reactive barrier. Residence time distributions of the recharge water at the monitoring points were obtained by a pulse tracer test. These distributions were used for calibrating a conservative transport and flow model of the aquifer. Finally, first order rates and retardation factors of several EOCs were estimated by fitting model outputs to observed concentrations. The estimation of the first order decay rates and retardation factors of several EOCs allowed the comparison of such values with values reported from other field sites and column experiments. The reactive barrier succeed in releasing organic carbon and achieving diverse redox condi- tions. The transformation of most EOCs was enhanced after the installation of the reactive barrier. In fact, first order rates and retardation factors were higher in the reactive barrier than in the rest of the aquifer and similar or higher than those from literature. In summary, addition of proposed reactive barrier significantly enhanced the performance of artificial recharge via infiltration basins, thus contributing to the renaturalization of recharged waters.
La recarga artificial de acuíferos a través de balsas de infiltración (AR) mejora la calidad del agua y aumenta recursos de aguas subterráneas, convirtiéndola en una técnica apropiada para la renaturalización de las aguas afectadas directa o indirectamente por los efluentes de aguas residuales. En este tipo de aguas la presencia de compuestos orgánicos emergentes (EOCs) es más que frecuente. Durante la recarga artificial este tipo de compuestos es eliminado principalmente debido a la adsorción y a la biotransformación. Para mejorar la eliminación de los EOCs durante la infiltración del agua de recarga se instaló una barrera reactiva en una balsa de infiltración. La barrera consistía en arena, compost vegetal, óxidos de hierro y arcilla. La finalidad del compost vegetal era por un lado la de aportar carbono orgánico disuelto para ser utilizado como principal fuente de carbono por la comunidad microbiana promoviendo así la generación de diversas condiciones redox, y por otro lado la de adsorber EOCs neutros. La Arcilla y los óxidos de hierro se pusieron con la intención de aumentar los sitios de adsorción para los EOCs catiónicos y aniónicos, respectivamente. La efectividad de la barrera en el campo se estudió comparando el comportamiento de los indicadores redox y de los EOCs antes y después de la instalación de la barrera. Mediante un ensayo de trazadores tipo pulso se obtuvieron las distribuciones de los tiempos de residencia del agua de recarga a los puntos de observación. Estas distribuciones se utilizaron para calibrar un modelo de flujo y transporte conservativo del acuífero. Por último, las tasas de degradación de primer orden y los factores de retardo de varios EOCs se estimaron mediante el ajuste de los resultados del modelo con las concentraciones observadas. Las tasas de degradación y los factores de retardo estimados se compararon con valores encontrados en la bibliografía. La barrera reactiva cumple su función aportando carbono orgánico y generando diversas condiciones redox. Muchos de los EOCs estudiados mostraron una mejor transformación cuando la recarga se realizó con la barrera reactiva. Las tasas de degradación y factores de retardo estimados en la barrera son mayores que los estimados para el resto del acuífero, y del mismo orden o superiores a los encontrados en la bibliografía. En resumen, la barrera reactiva propuesta mejora significativamente el rendimiento de la recarga artificial a través de balsas de infiltración, contribuyendo así a la renaturalización de las aguas recargadas

This thesis deals with the development of tools and analysis to characterize and predict artificial recharge and radial convergent solute transport processes in heterogeneous media. The goal is to provide new insights to understand how heterogeneity, which is the main natural source of uncertainty in decision-making processes related with groundwater applications, can be controlled and its effects predicted for practical purposes in these topics. For hydrogeological applications, accurate modeling of phenomena is needed, but it is uncertain. Uncertainty is derived from the spatio-temporal random distribution of hydrodynamic (physical, chemical and biological) variables affecting groundwater processes, which is translated into random distribution of modeling parameters and equations. Such randomness is of two types: epistemic, when it can be reduced increasing the sample frequency of an experiment; aleatory, when it cannot be reduced when more information is analyzed. Sometimes hydrodynamic processes occur at so small scales that they become impossible to characterize with traditional methods, and from a practical perspective, this is analogous to deal with aleatoric model parameters. However, if some constitutive relationship (either empirically, theoretically or physically based) can be built between processes across different scales, then small-scale processes can be reproduced by equivalent large-scale model parameters. Uncertainty becomes amenable to be treated as epistemic randomness, and large-scale characterization techniques can be used to improve the description, interpretation or prediction of these processes. This thesis deals with these topics. The manuscript is composed by two main parts (the first on artificial recharge and the second on solute transport), each of them divided into three chapters. In chapter 1 of each part, a tool is developed to obtain quantitative information to model a selected variable at coarse grid resolutions. In the case of artificial recharge, satellite images are used to model the spatial variability of the infiltration capacity on top soils with a metric-scale detail. In the case of solute transport, a new method to estimate density from particle distribution is shown. In chapters 2, it is explored what processes occurring at the fine scales can affect the interpretation of artificial recharge and solute transport processes at larger scales. In the first part, a combined method that joins satellite images and field data along with a simple clogging model is used to display the equally-possible spatio-temporal mapping of the infiltration capacity of topsoil during artificial pond flooding activities. In the second part, numerical three-dimensional models are used to simulate transport in heterogeneous media under convergent radial flow to a well at fine scale. It is shown that an appropriate model framework can reproduce similar observations on contaminant temporal distribution at controlling section similar to those obtained in the field tracer tests. It is also provided a physical explanation to describe the so-called anomalous late-time behavior on breakthrough curves which is sometimes observed in the reality at larger scales. In the chapters 3, models are used to define the uncertainty around operating parameters in the optic of prediction and management on artificial recharge and solute transport. In the first case, a probability framework is built to define the engineering risk of management of artificial recharge ponds due to random variability of the initial distribution of infiltration, which controls several important clogging factors based on theoretical approaches. In the case of solute transport, it is discussed how equivalent parameters based on mass-transfer models can be related with the geometrical distribution of hydraulic parameters in anisotropic formation, when convergent flow tracer tests are used.

The Bahamas is a small island nation that is dealing with the problem of freshwater shortage. All of the country’s freshwater is contained in shallow lens aquifers that are recharged solely by rainfall. The country has been struggling to meet the water demands by employing a combination of over-pumping of aquifers, transport of water by barge between islands, and desalination of sea water. In recent decades, new development on New Providence, where the capital city of Nassau is located, has created a large area of impervious surfaces and thereby a substantial amount of runoff with the result that several of the aquifers are not being recharged. A geodatabase was assembled to assess and estimate the quantity of runoff from these impervious surfaces and potential recharge locations were identified using a combination of Geographic Information Systems (GIS) and remote sensing. This study showed that runoff from impervious surfaces in New Providence represents a large freshwater resource that could potentially be used to recharge the lens aquifers on New Providence.

The Distrito Federal in Western Central Brazil is characterized by a high share of urban population and a predicted growth of population. The corresponding increasing water consumption is associated with a falling groundwater table. The existing wastewater treatment plants could reach their capacity limits due to further increasing amounts of urban wastewater in conjunction with heavy precipitation events. During these events, untreated wastewater can become a contamination source for protected resources such as soil and water. This problem can be solved by soil aquifer recharge. This is a unique technique to take the load off the treatment plants, to store the water in the aquifer, and to improve the water quality during the soil passage. The controlled infiltration of pretreated municipal wastewater in the tropical soils can ensure the regional groundwater balance and backup high quality water as a suitable drinking water resource. The objective of the present thesis was to define suitable soils and areas for a soil aquifer treatment in the Distrito Federal to support the decentralized wastewater treatment management. For the identification of suitable soils, representative samples were taken. The soil samples were examined with respect to their pedological and geochemical properties. For the characterization of the unsaturated hydraulic conditions, in situ infiltration tests and a 3D infiltration monitoring were performed. Additionally, the retention potentials for sewage ingredients were determined for each soil with unsaturated, hydrochemical and geoelectrical column tests. Thus, it was possible to calculate the retention potentials of each soil against the wastewater content of an artificial wastewater. The artificial wastewater with known composition was infiltrated through the soil columns. The retention potentials of the soils were calculated by balancing the hydrochemical data. Afterwards, for the implementation of the hydraulic data and the data from the column tests, a utility analysis was performed to merge all parameters. Finally, the field and laboratory studies were combined within a GIS-based usability analysis to blend the determined parameter with geo-data to identify suitable areas for a soil aquifer treatment. Parameters as slope, land use and land cover were included in this analysis. After the evaluation of the hydrochemical balances, predominantly the younger soils turn out as suitable for an artificial recharge with water of impaired quality because of their high retention potential for TOC. The Gleissolo featured a retention potential of almost 100 % for TOC. However, a high hydraulic conductivity in the soils is necessary to ensure an effective artificial recharge. The Gleissolo featured the lowest measured hydraulic conductivity in the field test with 1,12 x 10-8 m/s. Due to the consideration of the determined hydraulic and hydrochemical data in the utility analysis, each parameter was weighted to embrace the requirement of an effective artificial recharge. The results of the laboratory and field tests have shown that the soil group of Latossolos is suitable for a soil aquifer treatment. These soils offer the best infiltration characteristics and a good retention potential against sewage ingredients for an effective artificial groundwater recharge with pretreated wastewater. Additional to that, slope, land use/land cover, depth of soil, and a defined distance to conservation area were considered in a GIS-based usability analysis. Additionally, the categorized soils from the utility analysis were included to identify suitable regions. The outcome of the thesis is a GIS-based usability analysis map which shows suitable areas for a soil aquifer treatment ranked by their category of suitability. Additionally, the thesis provides crucial evidences for soil parameters which have positive effects on wastewater infiltration. In addition, the 3D infiltration monitoring and the measured resistivity distribution showed that the gravitatively controlled infiltration influences only the soil zone immediately beneath the irrigation. Furthermore, it was found that the proxy of the geoelectrical resistivity is not (sufficiently) conclusive for the sorption potential of conductive wastewater ingredients
O Distrito Federal, localizado no Centro-Oeste Brasileiro, é caracterizado por um intenso processo de urbanização o qual deve aumentar ainda mais nas próximas décadas. O correspondente crescimento no consumo de água está, também, associado ao rebaixamento dos níveis das águas subterrâneas. O atual sistema de tratamento de efluentes pode atingir seu limite de operação diante do crescimento demográfico e aumento de eventos extremos de chuva. Durante esses eventos, efluentes não tratados podem tornar-se uma fonte de contaminação aos recursos hídricos e solos. Uma solução é recarga artificial de águas subterrâneas. A mesma armazena o efluente pré-tratado nas águas subterrâneas e melhora a qualidade do mesmo durante o processo de percolação no solo. A infiltração controlada em solos tropicais pode contribuir para a qualidade das águas subterrâneas e balanço hídrico, servindo assim como fonte para o abastecimento de água. Essa tese tem como objetivo a identificação de áreas e solos propícios à recarga artificial de águas subterrâneas no Distrito Federal a fim de dar suporte à gestão decentralizada de tratamento de efluentes. Para a identificação dessas áreas, amostras representativas à diferentes tipos de solos foram obtidas. As amostras foram examinadas de acordo com suas propriedades pedológicas e geoquímicas. Para a caracterização das condições hidráulicas não saturadas, realizaram-se diversos testes de infiltração in situ, bem como o monitoramento 3D. Ainda, determinou-se para cada solo o potencial de retenção de poluentes através de testes de coluna insaturados, hidroquímico e geoelétricos. Dessa forma foi possível calcular os potenciais de retenção para cada solo quando utilizados efluentes sintéticos. Com base na contabilização de todos os dados hidroquímicos, calculou-se os potenciais de retenção de poluentes para o determinado efluente de composição conhecida. Mais a frente, para a implementação de dados hidráulicos e dados dos testes de coluna, utilizou-se uma análise de utilidade considerando todos os parâmetros. Finalmente, estudos de laboratório e campo foram combinados em uma análise baseada em sistema de informação geográfica (SIG). O mesmo permite o cruzamento de um determinado parâmetro obtido com uma base de dados georeferenciados (p. ex. classes de solos) a fim de identificar as áreas mais propícias. Parâmetros tais como declividade, uso e cobertura de solo foram incluídos nessa análise. Após a avaliação dos balanços hidroquímicos, identificou-se que os solos jovens possuem um alto potencial de retenção de carbono orgânico total (COT). Os mesmos mostraram-se adequados para recarga de águas subterrâneas com efluente residuário pré-tratado. Como exemplo, o Gleisolo apresentou um potencial de retenção de aproximadamente 100% de COT. No entanto, é importante lembrar que, a fim de garantir uma retenção efetiva, a condutividade hidráulica do solo deve ser alta. Nesse caso, o Gleisolo apresentou baixos valores no teste de campo com uma condutividade hidráulica de 1,12 x 10-8 m/s. Ainda, os dados hidráulicos e hidroquímicos medidos foram integrados à uma análise de uso-benefício. No caso, cada parâmetro recebe um peso de modo a atender às demandas de uma recarga efetiva de águas subterrâneas. Resultados mostram que o grupo de solo classificado com Latossolo é propício para a recarga de águas subterrâneas. O mesmo oferece a melhor característica de infiltração e potencial de retenção de contaminantes para uma recarga artificial com efluentes pré-tratados. Declividade, uso e ocupação de solo, profundidade do solo e uma distância devida de áreas de conservação foram contemplados na análise de utilidade baseada em SIG. Além disso, os colos caracterizados pela análise de uso-benefício foram incluídos com o intuito de identificar as regiões mais propícias para a prática. O resultado da tese é uma representação gráfica georeferenciada das áreas propícias para a aplicação de recarga artificial de águas subterrâneas. Ainda, a tese fornece evidências cruciais de parâmetros do solo que tem efeitos positivos na infiltração de efluentes pré-tratados. O monitoramento 3D de infiltração e a distribuição de resistividade medida mostram que infiltração controlada por gravidade influencia apenas a zona do solo imediata à superfície de irrigação. Mas a frente, foi determinado que o proxy da resistividade geoelétrica não é válido para o potencial de retenção de contaminantes condutores
Der Distrito Federal ist durch eine starke Urbanisierung geprägt. Das ohnehin bereits starke Bevölkerungswachstum wird Prognosen zufolge weiter zunehmen. Der damit verbundene Anstieg des Wasserverbrauchs wird auch in absinkenden Grundwasserständen widergespiegelt. Weiterhin ist das westliche Zentralbrasilien aufgrund seiner Lage in den wechselfeuchten Tropen durch eine starke Saisonalität der Niederschläge geprägt. Das erhöhte Abwasseraufkommen in Verbindung mit extremen Niederschlagsereignissen kann zu einer deutlichen Überbelastung der vorhandenen Kläranlagen führen. In Extremsituationen kann ungeklärtes Abwasser in die Bodenzone gelangen und somit Schutzgüter wie Boden und Wasser kontaminieren. Eine effiziente Maßnahme gegenüber der unkontrollierten Versickerung von ungeklärtem Abwasser sowie zur Vorbeugung absinkender Grundwasserspiegel ist die gezielte Infiltration von vorbehandeltem Abwasser in Verbindung mit einer Grundwasseranreicherung. Diese Maßnahme umfasst einen zusätzlichen Reinigungsschritt des vorgereinigten Abwassers und dient zur Vorbeugung gegenüber absinkenden Grundwasserspiegeln. Ziel der Arbeit war es, geeignete Böden und Flächen für eine Grundwasseranreicherung mit vorbehandeltem Abwasser im Distrito Federal auszuweisen. Zur Identifizierung geeigneter Böden wurden repräsentative Bodenproben auf ihre pedologischen und geochemischen Eigenschaften hin untersucht. Zusätzlich wurden in situ Durchlässigkeitstests und ein Versickerungsmonitoring aufgebaut, um zur Klärung der Infiltrationseigenschaften beizutragen. Für die Laboruntersuchungen wurden die Bodenproben im Hinblick auf ihre Schadstoffrückhaltepotentiale untersucht. Dazu wurden kombinierte hydrochemische und geoelektrische sowie ungesättigte Säulenversuche durchgeführt. Dadurch war es möglich, Rückschlüsse auf die Sorptionsleistung der Böden gegenüber den Abwasserinhaltsstoffen einer künstlichen Abwasserlösung schließen zu können. Die Bodensäulen wurden mit einem künstlichen Abwasser mit bekannter Schadstoffzusammensetzung überstaut. Auf der Grundlage der Bilanzierung aller hydrochemischen Daten wurden die Schadstoffrückhaltepotentiale für die Abwasserinhaltsstoffe berechnet. Anschließend wurden die experimentell ermittelten Parameter in einer Nutzwertanalyse zusammengefasst, um so geeignete Böden für eine effiziente Grundwasseranreicherung mit vorbehandeltem Abwasser zu identifizieren. Abschließend wurden die Feld- und Laboruntersuchungen mit einer GIS-basierten Nutzbarkeitsanalyse komplettiert, um die gemessenen Parameter mit weiteren vorliegenden, räumlich aufgelösten Daten verschneiden zu können. In diese Analyse wurden Parameter wie Gefälle, Landnutzung und Landbedeckung einbezogen. Bei der Auswertung der hydrochemischen Bilanzen kristallisierten sich vorwiegend die jungen Böden aufgrund ihrer hohen Schadstoffrückhaltepotentiale als geeignete Böden für eine Grundwasseranreicherung mit vorbehandeltem Abwasser heraus. Exemplarisch wies der Gleissolo ein Sorptionspotential von fast 100 % für den Parameter TOC auf. Allerdings müssen Böden für eine effektive Grundwasseranreicherung mit vorbehandeltem Abwasser zusätzlich zu den hohen Sorptionsleistungen auch hohe hydraulische Durchlässigkeiten aufweisen. Für den Gleissolo wurde im Feldversuch die niedrigste hydraulische Durchlässigkeit von 1,12 x 10-8 m/s bestimmt. Durch die Einbindung der gemessenen hydraulischen und hydrochemischen Daten in eine Nutzwertanalyse konnten diese Parameter gewichtet werden, um so den Ansprüchen einer effektiven Grundwasseranreicherung gerecht zu werden. Im Ergebnis der durchgeführten Untersuchungen hat sich gezeigt, dass sich die Bodengruppe der Latossole besonders gut für eine Grundwasseranreicherung mit vorbehandeltem Abwasser eignet. Diese Böden weisen die besten Infiltrationsbedingungen sowie gute Sorptionseigenschaften für eine effizient gestaltete Grundwasseranreicherung auf. Mit Hilfe der GIS-basierten Nutzbarkeitsanalyse geografischer Parameter wurden Flächen ausgezeichnet, die sich in Bezug auf Gefälle, Landnutzung/Landbedeckung, Bodentiefe und einer adäquaten Distanz zu Schutzgebieten für eine Grundwasseranreicherung mit vorbehandeltem Abwasser eignen. Zusätzlich wurden die mit Hilfe der Nutzwertanalyse kategorisierten Böden in die Flächenidentifizierung einbezogen. Das Resultat dieser Arbeit liegt in Form einer Karte vor, in der die Gebiete, die für eine Grundwasseranreicherung mit vorbehandeltem Abwasser geeignet sind, nach Kategorien geordnet, verzeichnet sind. Zusätzlich dazu liefert die Arbeit entscheidende Hinweise auf Bodeneigenschaften, die sich positiv auf eine Abwasserinfiltration auswirken. Darüber hinaus konnte durch das geoelektrische 3D-Monitoring und der dabei gemessenen Verteilung des spezifischen elektrischen Widerstandes gezeigt werden, dass die Infiltration gravitativ gesteuert nur die Bodenzone direkt unterhalb der Verrieselung beeinflusste. Weiterhin wurde festgestellt, dass das Proxy des geoelektrischen Widerstandes im Labormaßstab nicht aussagekräftig genug ist, um Rückschlüsse auf die Sorption leitfähigkeitsrelevanter Abwasserinhaltsstoffe geben zu können

Seawater intrusion (SWI) is a widespread environmental problem, particularly in arid and semi-arid coastal areas. Unplanned prolonged over-pumping of groundwater is the most important factor in SWI that could result in severe deterioration of groundwater quality. Therefore, appropriate management strategies should be implemented in coastal aquifers to control SWI with acceptable limits of economic and environmental costs. This PhD project presents the development and application of a simulation-optimization (S/O) model to assess different management methods of controlling saltwater intrusion while satisfying water demands, and with acceptable limits of economic and environmental costs, in confined and unconfined coastal aquifers. The first S/O model (FE-GA) is developed by direct linking of an FE simulation model with a multi-objective Genetic Algorithm (GA) to optimize the efficiency of a wide range of SWI management scenarios. However, in this S/O framework, several multiple calls of the simulation model by the population-based optimization model, evaluating best individual candidate solutions resulted in a considerable computational burden. To solve this problem the numerical simulation model is replaced by an Evolutionary Polynomial Regression (EPR)-based surrogate model in the next S/O model (EPR-GA). Through these S/O approaches (FE-GA and EPR-GA) the optimal coordinates and rates of the both abstraction and recharge barriers are determined in the studied management scenarios. As a result, a new combined methodology, so far called ADRTWW, is proposed to control SWI. The ADRTWW model consists of deep Abstraction of saline water near the coast followed by Desalination of the abstracted water to a potable level for public uses and simultaneously Recharging the aquifer using a more economic source of water such as treated wastewater (TWW). In accordance to the available recharge options (injection through well or infiltration from surface pond), the general performance of ADRTWW is evaluated in different hydro-geological settings of the aquifers indicating that it offers the least cost and least salinity in comparison with other scenarios. The great capabilities of both developed S/O models in identification of the best management solutions and the optimal coordinates and rates of the abstraction well and recharge well/pond are discussed. Both FE-GA and EPR-GA can be successfully employed by a robust decision support system. In the next phase of the study, the general impacts of sea level rise (SLR), associated with its transgression nature along the coastline surface on the saltwater intrusion mechanism are investigated in different hypothetical and real case studies of coastal aquifer systems. The results show that the rate and the amount of SWI are considerably greater in aquifers with flat shoreline slopes compared with those with steep slopes. The SWI process is followed by a significant depletion in quantity of freshwater resources at the end of the century. The situation is exacerbated with combined action of SLR and groundwater withdrawals. This finding is also confirmed by 3D simulation of SWI in a regional coastal aquifer (Wadi Ham aquifer) in the UAE subjected to the coupled actions of SLR and pumping.

Dissertação de mest., Recursos Hídricos, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011
According to the International Panel for Climatic Changes (IPCC), decreases in mean annual precipitation and changes in its annual distribution associated with increases in temperature, can lead to significant decrease in recharge of aquifers in southern Europe, which can turn into a major problem at a large regional scale. Moura-Ficalho aquifer (MF) is a karstic-fissured aquifer made of Paleozoic carbonate rocks (dolomitic rocks and marbles) in the Alentejo region, located in south of Portugal. Beside this predicted decrease in recharge, in this aquifer the situation was increased by soil erosion and clogging of sink holes and other karstic recharge structures, so in MF decrease in recharge has been detected and, for this reason more research and measures to reverse this desertification evolution are required. The unbalanced condition of this aquifer was first detected after the implementation of a monitoring piezometric network (Costa, in ERHSA, 2001) and the calibration of a groundwater flow model using data collected from October 2000 until December 2005 (Costa, 2008). According to the transient model developed on a monthly base, by A. Costa, water recharge was not enough to compensate the water losses by the aquifer. The simulation period included one wet year (2000/01), three mean years (from 2001 to 2004) and a very dry year (2004/05). However, mean annual precipitation in these five years was 530 mm, which equals the mean annual precipitation estimated by considering long time series. Furthermore, according to predicted climate changes, the climate trends towards drier weather and so, this problem will tend to become increased, probably not only in MF but also in other karstic aquifer in southern part of Portugal. This work intends to investigate the relationship between groundwater and surface water, and to detect areas where the natural recharge is taking place and where it should be increased in order to mitigate this environmental problem. To reach this aim, several scenarios of the former groundwater modeling outputs were worked out with the help of Geographic Information System (Arc GIS). Also the subject about artificial recharge of aquifers was developed and applied to this region.

This research project focuses on the Walla Walla River Basin located on the east side of the states of Oregon and Washington, USA. With the support and collaboration of the Walla Walla Basin Watershed Council, this work embraces four research topics. The first topic includes the feasibility study of artificial aquifer recharge in the Walla Walla Basin. Through development and application of a regional hydrological model, a methodology for evaluating locations of artificial aquifer recharge is presented with a test case. The second research topic evaluates the recharge rates observed from pilot test studies of artificial aquifer recharge. Scale dependence of recharge rates should be considered when excessive induced groundwater mounding forms beneath the infiltrating basins. The third topic utilizes groundwater tracers and simulation models to evaluate the hydraulic connection of springs to infiltrating basins of artificial aquifer recharge. Finally, the fourth topic as a proof of a technique, utilizes distributed temperature sensing technology with a pair of black and white coated fiber optic cables to estimate the effective exposure to solar radiation over the Walla Walla River.
Graduation date: 2013

Artificial recharge and rainwater harvesting methods are being applied for mitigating effects of groundwater depletions in severe over-drafting urban and rural situations. When the aquifer to be recharged is situated at some depth below the ground surface and topped by a semi-previous layer with a large resistance against vertical water movement, recharge wells are the most appropriate solution. Water is injected by free or forced recharge technique by maintaining constant or variable head or rate of injection in the recharge well. A review of literature, carried out in two parts, looks into the aspects and performance of the practical field applications of recharge wells all over the world in Chapter II, whereas available theoretical solutions are reviewed in chapter III. The review indicates that free recharge conditions are analysed using slug theories and mirror image type curve analysis is helpful in dealing with forced recharge cases. Many slug test and pumping test theories developed focus either on simplistic recharge conditions or homogeneous hydro-geological conditions. Also, separate developments exist in the areas of large diameter well and flow to multi-aquifer system. These developments are mainly concentrated on constant wellhead boundary conditions with no well loss. Many researchers have dealt effect of pumping on base flow numerically, but the study on the impacts of recharge on base flow has not been noticed. One more practical issue, which has not been studied, is the aquifer clogging during well injection, though related background research on filtration phenomena is comparatively well established. Analytical solution for recharge in a finite aquifer from a large diameter well under variable head is obtained in Chapter IV. Furthermore, issues of analytical solution difficulty, in the available solution with constant head boundary condition are resolved and extended using Discrete Kernel approach to variable heads. Usefulness of choosing the variable head boundary condition lies in the advantage that continuous pouring of water in to the recharge well is not a necessary condition. As well and aquifer clogging is minimum in hard rock terrains, present solution is useful for estimating the pressure heads and recharge rates in the well flooding techniques frequently used in hard rock regions. For the case of free recharge in confined aquifers, available slug test theories do not consider appropriate well storage and well loss, as these may not be significant in the case of short duration test with instantaneous slug. Also slug theories are not extendable to multi-aquifer wells. Analytical solutions are obtained for free recharge condition for both single and multiple layer aquifers in chapter V, also incorporating well loss, well storage and friction loss. Parametric studies are made to see the effect of hydro-geological parameter namely; transmissivity and storativity, on recharge rates and head buildups. Theis (1935) solution is provided with well storage effects for the entire period of recharge, using Duhamel’s convolution theorem. Comparison with Cooper et al. (1967) shows, that the present solution could be useful for long-term non-instantaneous free recharge data analysis. Relationship between diffusivity and time to decay has been developed, which is useful for aquifer parameter estimation using recharge test data. Similar improvement is feasible for other existing type curves also including leaky aquifers. Analytical solutions for free recharge with constant well loss, variable well loss and losses due to friction have been developed. Comparison indicates better solution with losses due friction, which is also a more easily measurable physical parameter as compared to other well loss constants. Free recharge solutions provide unique opportunity to estimate the recharge rates in the individual aquifers of single and multi-layered aquifer. Well bore interaction has been accounted through recharge well injecting water to multi-aquifers. Specific analytical solutions are developed for the cases of free recharge in hard rock multi-layered aquifers. Present state of the art for recharge well considers forced recharge as mirror image of the pumping test solutions, type curves of which are found more difficult to fit in to the recharge test data. Again, deviation in type curve match lies in considering well storage, well clogging and aquifer clogging effects. In chapter VI analytical forced recharge solutions are developed for constant and variable rate of injection. Mirror image Theis (1935) solution is coupled with well storage during the recharge period to improve the existing solution and make it suitable for recharge computation after comparing it with Popodopulos and Cooper (1967) solution. Well bore interaction in case of multi-layered aquifer has been considered. Similar exercises are possible with existing solutions other than Theis (1935) including those for leaky aquifers. Type curves for recharge for various diffusivity ratios have been developed. Constant and variable well loss is considered for forced recharge in single as well as multi-layered aquifer. Results say that present solutions are more accurate in terms of well storage, which has significant influence on well injection as compared to well pumping. In the case of pumping, well storage effects are dominant in the initial times, where as it effects the entire recharge cycle, also depend upon the aquifer diffusivity and the recharge column dimensions. Significant influence of well loss in case of forced well recharge has been taken care of by considering linear trend of deteriorating well condition between times dependant Walton’s well loss constant. In Chapter VII, aquifer clogging, changing with time has been analysed using numerical modelling technique and applying the results of the filtration experiments reported in the literature. Inclined initial piezometric water table condition is found effective towards observation well water level and is considered for simulation of the observation well water level of Hansol project. The methodology is transferable for analyzing other injection project also. Base flow on regional scale is affected by the location, rate of injection and number of wells. In the case of Bamnod injection well project, base flow retained in the aquifer, is reducing with the increase in the quantity of injected water. This conclusion may not always be same everywhere, however, this aspect needs to be investigated. Chapter VIII summaries and highlights the conclusions drawn out of the present research study. It has been summarized that the Chapters IV, V and VI develop analytical solutions for recharge rates under unsteady wellhead condition by coupling existing groundwater flow solution with Duhamel’s convolution theorem. It provides the well storage effects throughout the recharge cycle, which unlike in pumping cases, could be significant in recharge cases. Second foremost specific requirement for a well recharge may be the consideration of head loss. In free recharge cases friction factor per unit diameter of recharge well is found a better physically computable parameter, where as well loss constants suggested by Walton (1962) could bring the head loss effects in the developed solutions for forced recharge. Free and forced recharge solutions developed for single aquifer are further extended to multi-aquifer system with respective head loss effects and well bore interaction. This is an useful contribution owing to the fact that no multi-aquifer solution considers aquifer interactions through recharge well and equivalent single aquifer theory worked for the multi-aquifer system without head loss All the solutions in Chapters IV, V and VI are found sensitive towards well radius and could analyze recharge behavior at the well face with horizontal initial piezometric surface. Simulation of the response in an observation well situated 50 m away from the recharge well is found inappropriate with the present solution. Therefore in the Chapter VII, to solve the solution difficulty, analysis is extended for the observation well, some distant away from the recharge well face, using numerical solution technique. Heterogeneity in the flow medium between the recharge well and the observation well is considered as per the time dependant aquifer clogging, based upon theory of filtration. Recharge well in general has been considered as a technology, which would increase the groundwater storage. With a case study it is found that groundwater regime also plays a crucial role in this respect. Present thesis also provides specific solution to practical issues like; estimation of diffusivity from time to decay of recharge, friction loss in the recharge well, time variant well loss as per recharge well condition, effect of sudden pump shut down, control of injection rates against recharge well over flooding, recharge rates to individual aquifers of a multi-aquifer system and multiple well recharge options. Though the scope of the present research is confined to aquifer-aquiclude system only, it could easily be extended to various other hydro-geological setups also. Unique feature of the applied analytical solution technique lies in the flexibility of transformation between head and flux boundary conditions. This provides an opportunity to compute recharge rates and corresponding heads simultaneously with any kind of boundary conditions.

Διερευνώνται επιμέρους θέματα διαχείρισης παράκτιων υδροφορέων που αφορούν στην διασφάλιση της αειφορίας των υπόγειων αποθεμάτων μέσω (α) της προστασία τους έναντι στην υποβάθμιση της ποιότητάς τους που μπορεί να προέλθει από τη διείσδυση του θαλασσινού νερού και από ανθρωπογενείς δραστηριότητες και (β) της διασφάλισης της κάλυψης των αναγκών σε υπόγειο νερό κατά τις περιόδους αυξημένης ζήτησης. Η διερεύνηση βασίζεται στη χρήση δύο αριθμητικών μοντέλων υπόγειας ροής που λαμβάνουν υπόψη τις διαφορές πυκνότητας μεταξύ γλυκού και αλμυρού νερού και περιλαμβάνει τα ακόλουθα: Παρουσιάζεται ο τρόπος με τον οποίο διατυπώνονται και επιλύονται οι εξισώσεις που περιγράφουν την υπόγεια ροή υπό την επιρροή διαφορών πυκνότητας σε δύο ευρέως χρησιμοποιούμενα αριθμητικά μοντέλα, που είναι το μοντέλο SEAWAT-2000 (Langevin et al., 2003) και το μοντέλο SUTRA v2.2 (Voss & Provost, 2010). Βάσει των ανωτέρω και της εμπειρίας που αποκτήθηκε από την παράλληλη εφαρμογή τους, οι δύο κώδικες αξιολογούνται συγκριτικά και διατυπώνονται κριτήρια, στα οποία μπορεί να βασιστεί η επιλογή του κατά περίπτωση προσφορότερου κώδικα. Γίνεται η ρύθμιση αριθμητικού μοντέλου, το οποίο είναι βασισμένο στον κώδικα SEAWAT-2000, για τον παράκτιο υδροφορέα του Γλαύκου π., ο οποίος βρίσκεται στα νότια της πόλης των Πατρών και αποτελεί σημαντικό υδατικό πόρο για την περιοχή. Η ρύθμιση του μοντέλου βασίζεται σε μετρήσεις της υπόγειας στάθμης που προέρχονται από ένα σχετικά πυκνό δίκτυο γεωτρήσεων παρατήρησης το οποίο όμως έχει χρονικά περιορισμένη διάρκεια λειτουργίας. Το δίκτυο κατασκευάστηκε στα πλαίσια του προγράμματος INTERREG Ελλάδα – Ιταλία, 2000 – 2006, σε συνεργασία του Εργαστηρίου Υδραυλικής Μηχανικής του Πανεπιστημίου Πατρών και της Δημοτικής Επιχείρησης Ύδρευσης και Αποχέτευσης της Πάτρας (Δ.Ε.Υ.Α.Π.) και ολοκληρώθηκε στα μέσα του 2008. Η διαδικασία ρύθμισης του μοντέλου περιλαμβάνει τα εξής: (α) Τη συστηματική οργάνωση, συνδυασμό και αξιολόγηση των διαθέσιμων πληροφοριών σε λογισμικό συστημάτων γεωγραφικών πληροφοριών. (β) Την εφαρμογή υδραυλικών και στατιστικών μεθόδων σε συνδυασμό με την τροποποίηση και εφαρμογή μεθόδων αριθμητικής προσομοίωσης αντλητικών δοκιμών για τον προσδιορισμό των υδραυλικών χαρακτηριστικών του υδροφορέα. (γ) Τη συνδυαστική ανάλυση υδρολογικών δεδομένων και χρονοσειρών της υπόγειας στάθμης για την εκτίμηση των συνιστωσών του υδρολογικού ισοζυγίου. (δ) Τον καθορισμό κατάλληλων κριτηρίων αξιολόγησης των προσομοιώσεων. (ε) Την εμπειρική ρύθμιση των παραμέτρων του μοντέλου, η οποία επειδή έγινε παράλληλα με την συλλογή των μετρήσεων της υπόγειας στάθμης πραγματοποιήθηκε για δύο περιόδους, κατ’ αρχήν για την περίοδο 2008-2010 και εν συνεχεία για την περίοδο 2010-2012 και (στ) την εκτέλεση προσομοιώσεων Monte Carlo για την πραγματοποίηση καθολικής ανάλυσης ευαισθησίας (global sensitivity analysis, βλ. Saltelli et al., 2004) και τη διερεύνηση ύπαρξης περισσοτέρων συνδυασμών των τιμών των παραμέτρων του μοντέλου που οδηγούν σε παρόμοια αποτελέσματα (equifinality thesis, Beven, 2006). Από τη ρύθμιση του μοντέλου με τη βοήθεια των μετρήσεων της υπόγειας στάθμης που συλλέχτηκαν με το δίκτυο παρατήρησης προέκυψαν πληροφορίες για τους μηχανισμούς εμπλουτισμού του υδροφορέα στις διάφορες περιοχές, κάτι που είναι σημαντικό για τη διαχείρισή του. Το ρυθμισμένο μοντέλο του παράκτιου υδροφορέα του Γλαύκου χρησιμοποιήθηκε για την εξέταση θεμάτων διαχείρισης του υδροφορέα: (α) Προσδιορίστηκαν οι ζώνες τροφοδοσίας των γεωτρήσεων της ΔΕΥΑΠ με χρήση του κώδικα MODPATH v3 (Pollock, 1994) και εκτιμήθηκε η τρωτότητα αυτών των γεωτρήσεων. Διαπιστώθηκε ότι οι γεωτρήσεις που βρίσκονται κοντά στην κοίτη του Γλαύκου, όπως συμβαίνει με πολλές από τις γεωτρήσεις της ΔΕΥΑΠ, αντλούν σχεδόν αποκλειστικά νερό που προέρχεται από τον ποταμό. Έτσι είναι δυνατόν να προσβληθούν από ρυπάνσεις του νερού του ποταμού καθώς επίσης και από ανθρωπογενείς δραστηριότητες στις παρόχθιες ζώνες. (β) Εκτιμήθηκε ο κίνδυνος διείσδυσης θαλασσινού νερού σε περίπτωση εμφάνισης περιόδων ξηρασίας, για δύο διαφορετικά σενάρια αντλήσεων: ένα σύμφωνα με το σημερινό καθεστώς χρήσης του υπόγειου νερού και ένα για την αύξηση των αντλήσεων κατά 50%. Διαπιστώθηκε ότι για ξηρασία διάρκειας τεσσάρων ετών και αύξηση των αντλούμενων ποσοτήτων τα φαινόμενα υφαλμύρισης θα είναι έντονα. Με την επάνοδο όμως των μέσων υδρολογικών συνθηκών ο υδροφορέας ανακάμπτει. (γ) Για συνθήκες ξηρασίας εξετάστηκε η αποτελεσματικότητα του τεχνητού εμπλουτισμού για τον περιορισμό της διείσδυσης του θαλασσινού νερού. Ως μέθοδος εμπλουτισμού εξετάστηκε η εποχιακή αύξηση της στάθμης του νερού στον ποταμό με τη βοήθεια φουσκωτών φραγμάτων (βλ. Κωτσοβίνος, 1999). Διαπιστώθηκε ότι με τη μέθοδο αυτή μπορεί να επιτευχθεί σημαντική αύξηση των υπόγειων αποθεμάτων. Τέλος, εξετάζεται ως μέτρο προστασίας έναντι της διείσδυσης του θαλασσινού νερού η τεχνική των υπόγειων φραγμών. Επειδή στις μελέτες της τεχνικής αυτής που έχουν παρουσιαστεί στη βιβλιογραφία (π.χ. Luyun et al., 2011) έμφαση δίνεται μόνο στην επιρροή των γεωμετρικών χαρακτηριστικών των φραγμών (απόσταση από την ακτή, βάθος φραγμού), έγινε στην παρούσα εργασία συστηματική διερεύνηση της συναρτησιακής σχέσης ανάμεσα στην αποτελεσματικότητα της μεθόδου και τα χαρακτηριστικά τόσο των φραγμών όσο και του υδροφορέα (υδραυλική αγωγιμότητα, ανισοτροπία, υδρομηχανική διασπορά, παροχή γλυκού νερού προς τη θάλασσα, αντλήσεις στην παράκτια ζώνη, υλικό κατασκευής του φραγμού). Η διερεύνηση έγινε με τη βοήθεια του αριθμητικού μοντέλου SUTRA 2.2 (Voss and Provost, 2010), για δύο τύπους υπόγειων φραγμών: τους διαφραγματικούς τοίχους και τα υπόγεια φράγματα. Δίδονται διαγράμματα και αναλυτικές σχέσεις με χρήση αδιάστατων μεταβλητών και για εύρος τιμών των μεταβλητών αυτών που μπορούν να χρησιμοποιηθούν για τη διαστασιολόγηση φραγμών σε εφαρμογές πεδίου. Βάσει των αποτελεσμάτων που προκύπτουν από τη διερεύνηση της προαναφερθείσας συναρτησιακής σχέσης και χρησιμοποιώντας και το μοντέλο του Γλαύκου, εξετάστηκε η αποτελεσματικότητα της κατασκευής ενός φραγμού περιορισμένου μήκους στον υδροφορέα. Διαπιστώθηκε ότι πέραν του περιορισμού της διείσδυσης αλμυρού νερού σε περιόδους ξηρασίας που επιτυγχάνεται, ο φραγμός επιταχύνει την υποχώρηση της αλμυρής σφήνας όταν επανέλθουν οι συνήθεις υδρολογικές συνθήκες.
In the present study coastal aquifer management issues are investigated. These issues concern measures which ensure the sustainability of the coastal groundwater and particularly: (a) protective measures against the degradation of groundwater caused by saltwater intrusion and human activities and (b) measures allowing the availability of sufficient volumes of fresh groundwater during periods of high demand. The investigation is based on the application of two numerical codes, which are suitable for simulating the groundwater flow under the influence of density differences. The investigation procedure is as follows. The application of the equations of groundwater flow with density differences and transport, the limitations and the advantages are presented for two widely used numerical models, the SEAWAT-2000 code (Langevin et al., 2003) and the SUTRA v.2.2 code (Voss & Provost, 2010). Based on the analysis above and on the experience acquired through the parallel use of the two codes, basic criteria are derived that allow for the selection of the code that best suits the needs of a certain problem. The investigation focuses on the Glafkos coastal aquifer, which is located at north Peloponnese (Greece), south of the city of Patras and is an important source of freshwater for the region. For this aquifer the SEAWAT-2000 code is implemented and calibrated. The model calibration is based on groundwater level time series that were registered by a relatively dense monitoring network, whose operation time, however, is limited. The network of the monitoring wells was constructed during 2007-2008 in cooperation of the Hydraulic Engineering Laboratory (Department of Civil Engineering, University of Patras) and the Municipal Enterprise of Water Supply and Sewage of Patras (DEYAP), in the frame of the project INTERREG IIIA GREECE-ITALY. The calibration procedure is based on: (a) The application of a G.I.S. system to organize, combine, analyse and evaluate the available information. (b) The application of hydraulic and statistical methods combined with the modification and application of pumping tests simulation methods, for the estimation of the hydraulic parameters of the coastal aquifer. (c) The combined analysis of hydrological data and groundwater level time series for the estimation of the aquifers water budget components. (d) The establishment of appropriate criteria for the evaluation of simulation results. (e) The empirical calibration of the model is performed for two periods, i.e. the period 2008-2010 and the period 2010-2012. This procedure is due to the availability of the groundwater level time series which were registered parallel to the model calibration. (f) The application of the Monte-Carlo method in order to investigate the probability that different combinations of model parameters give similar or better simulation results. The model calibration led to a better understanding of the aquifers recharge mechanisms which is crucial for the development of a groundwater management policy and the implementation of a management plan. The calibrated groundwater model of the Glafkos coastal aquifer is used for the investigation and evaluation of coastal aquifer management applications: (a) The capture zones of the municipal production wells are delineated by applying the MODPATH v3 code (Pollock, 1994). It is found out that the production wells that are located close to the Glafkos River, as it is the fact for the majority of the municipal production wells, pump water that originates almost exclusively from the river. Consequently, polluted water from the river or polluting human activities close to the riverbank can affect the quality of the pumped water. (b) The saltwater intrusion risk is estimated, in case of a prolonged drought period. Two cases are investigated; the first considers the current pumping rates of groundwater while the second considers a 50% increased pumping. It is found out that a four-year drought period combined with an increase of the groundwater exploitation will lead to significant saltwater intrusion problems. (c) The applicability and effectiveness of in-channel artificial recharge with the use of rubber dams, as a countermeasure against the saltwater intrusion, which may be induced by a four-year drought period, is investigated. It is found that the method is applicable and effectively reduces the intrusion of saltwater. Further it increases the groundwater storage in the aquifer. Finally, the construction of a cutoff wall which covers only a small part of the aquifers width, is evaluated as a countermeasure to saltwater intrusion problems which may arise in Glafkos coastal aquifer. Due to the fact that existing studies on the technique of the subsurface barriers focus only on the influence of the geometrical characteristics of barriers covering the whole width of the aquifer, a systematic investigation is curried out on the functional relationship between the effectiveness of the barriers and all the parameters influencing it, i.e. the geometrical characteristics of the barriers, the aquifer parameters (the hydraulic conductivity, anisotropy, hydromechanical dispersion, groundwater flow towards the sea) and the pumping rate. The investigation is curried out by the use of the finite element code SUTRA v.2.2 and concerns two types of barriers; the subsurface dams and the cutoff walls. The results include graphs and functional relationships for the assessment of the effect of subsurface dams and cutoff walls and the design of such structures. The results are presented in terms of dimensionless variables, with ranges suitable for field applications. Based on these results, a cutoff wall of small width is designed for the Glafkos coastal aquifer. Its effectiveness is evaluated by applying the calibrated SEAWAT-model of the coastal aquifer. It is shown that the cutoff wall not only reduces the saltwater intrusion during drought periods, but also it reduces the retreat time of the saltwater front under normal hydrological conditions.

The Distrito Federal in Western Central Brazil is characterized by a high share of urban population and a predicted growth of population. The corresponding increasing water consumption is associated with a falling groundwater table. The existing wastewater treatment plants could reach their capacity limits due to further increasing amounts of urban wastewater in conjunction with heavy precipitation events. During these events, untreated wastewater can become a contamination source for protected resources such as soil and water. This problem can be solved by soil aquifer recharge. This is a unique technique to take the load off the treatment plants, to store the water in the aquifer, and to improve the water quality during the soil passage. The controlled infiltration of pretreated municipal wastewater in the tropical soils can ensure the regional groundwater balance and backup high quality water as a suitable drinking water resource. The objective of the present thesis was to define suitable soils and areas for a soil aquifer treatment in the Distrito Federal to support the decentralized wastewater treatment management. For the identification of suitable soils, representative samples were taken. The soil samples were examined with respect to their pedological and geochemical properties. For the characterization of the unsaturated hydraulic conditions, in situ infiltration tests and a 3D infiltration monitoring were performed. Additionally, the retention potentials for sewage ingredients were determined for each soil with unsaturated, hydrochemical and geoelectrical column tests. Thus, it was possible to calculate the retention potentials of each soil against the wastewater content of an artificial wastewater. The artificial wastewater with known composition was infiltrated through the soil columns. The retention potentials of the soils were calculated by balancing the hydrochemical data. Afterwards, for the implementation of the hydraulic data and the data from the column tests, a utility analysis was performed to merge all parameters. Finally, the field and laboratory studies were combined within a GIS-based usability analysis to blend the determined parameter with geo-data to identify suitable areas for a soil aquifer treatment. Parameters as slope, land use and land cover were included in this analysis. After the evaluation of the hydrochemical balances, predominantly the younger soils turn out as suitable for an artificial recharge with water of impaired quality because of their high retention potential for TOC. The Gleissolo featured a retention potential of almost 100 % for TOC. However, a high hydraulic conductivity in the soils is necessary to ensure an effective artificial recharge. The Gleissolo featured the lowest measured hydraulic conductivity in the field test with 1,12 x 10-8 m/s. Due to the consideration of the determined hydraulic and hydrochemical data in the utility analysis, each parameter was weighted to embrace the requirement of an effective artificial recharge. The results of the laboratory and field tests have shown that the soil group of Latossolos is suitable for a soil aquifer treatment. These soils offer the best infiltration characteristics and a good retention potential against sewage ingredients for an effective artificial groundwater recharge with pretreated wastewater. Additional to that, slope, land use/land cover, depth of soil, and a defined distance to conservation area were considered in a GIS-based usability analysis. Additionally, the categorized soils from the utility analysis were included to identify suitable regions. The outcome of the thesis is a GIS-based usability analysis map which shows suitable areas for a soil aquifer treatment ranked by their category of suitability. Additionally, the thesis provides crucial evidences for soil parameters which have positive effects on wastewater infiltration. In addition, the 3D infiltration monitoring and the measured resistivity distribution showed that the gravitatively controlled infiltration influences only the soil zone immediately beneath the irrigation. Furthermore, it was found that the proxy of the geoelectrical resistivity is not (sufficiently) conclusive for the sorption potential of conductive wastewater ingredients.
O Distrito Federal, localizado no Centro-Oeste Brasileiro, é caracterizado por um intenso processo de urbanização o qual deve aumentar ainda mais nas próximas décadas. O correspondente crescimento no consumo de água está, também, associado ao rebaixamento dos níveis das águas subterrâneas. O atual sistema de tratamento de efluentes pode atingir seu limite de operação diante do crescimento demográfico e aumento de eventos extremos de chuva. Durante esses eventos, efluentes não tratados podem tornar-se uma fonte de contaminação aos recursos hídricos e solos. Uma solução é recarga artificial de águas subterrâneas. A mesma armazena o efluente pré-tratado nas águas subterrâneas e melhora a qualidade do mesmo durante o processo de percolação no solo. A infiltração controlada em solos tropicais pode contribuir para a qualidade das águas subterrâneas e balanço hídrico, servindo assim como fonte para o abastecimento de água. Essa tese tem como objetivo a identificação de áreas e solos propícios à recarga artificial de águas subterrâneas no Distrito Federal a fim de dar suporte à gestão decentralizada de tratamento de efluentes. Para a identificação dessas áreas, amostras representativas à diferentes tipos de solos foram obtidas. As amostras foram examinadas de acordo com suas propriedades pedológicas e geoquímicas. Para a caracterização das condições hidráulicas não saturadas, realizaram-se diversos testes de infiltração in situ, bem como o monitoramento 3D. Ainda, determinou-se para cada solo o potencial de retenção de poluentes através de testes de coluna insaturados, hidroquímico e geoelétricos. Dessa forma foi possível calcular os potenciais de retenção para cada solo quando utilizados efluentes sintéticos. Com base na contabilização de todos os dados hidroquímicos, calculou-se os potenciais de retenção de poluentes para o determinado efluente de composição conhecida. Mais a frente, para a implementação de dados hidráulicos e dados dos testes de coluna, utilizou-se uma análise de utilidade considerando todos os parâmetros. Finalmente, estudos de laboratório e campo foram combinados em uma análise baseada em sistema de informação geográfica (SIG). O mesmo permite o cruzamento de um determinado parâmetro obtido com uma base de dados georeferenciados (p. ex. classes de solos) a fim de identificar as áreas mais propícias. Parâmetros tais como declividade, uso e cobertura de solo foram incluídos nessa análise. Após a avaliação dos balanços hidroquímicos, identificou-se que os solos jovens possuem um alto potencial de retenção de carbono orgânico total (COT). Os mesmos mostraram-se adequados para recarga de águas subterrâneas com efluente residuário pré-tratado. Como exemplo, o Gleisolo apresentou um potencial de retenção de aproximadamente 100% de COT. No entanto, é importante lembrar que, a fim de garantir uma retenção efetiva, a condutividade hidráulica do solo deve ser alta. Nesse caso, o Gleisolo apresentou baixos valores no teste de campo com uma condutividade hidráulica de 1,12 x 10-8 m/s. Ainda, os dados hidráulicos e hidroquímicos medidos foram integrados à uma análise de uso-benefício. No caso, cada parâmetro recebe um peso de modo a atender às demandas de uma recarga efetiva de águas subterrâneas. Resultados mostram que o grupo de solo classificado com Latossolo é propício para a recarga de águas subterrâneas. O mesmo oferece a melhor característica de infiltração e potencial de retenção de contaminantes para uma recarga artificial com efluentes pré-tratados. Declividade, uso e ocupação de solo, profundidade do solo e uma distância devida de áreas de conservação foram contemplados na análise de utilidade baseada em SIG. Além disso, os colos caracterizados pela análise de uso-benefício foram incluídos com o intuito de identificar as regiões mais propícias para a prática. O resultado da tese é uma representação gráfica georeferenciada das áreas propícias para a aplicação de recarga artificial de águas subterrâneas. Ainda, a tese fornece evidências cruciais de parâmetros do solo que tem efeitos positivos na infiltração de efluentes pré-tratados. O monitoramento 3D de infiltração e a distribuição de resistividade medida mostram que infiltração controlada por gravidade influencia apenas a zona do solo imediata à superfície de irrigação. Mas a frente, foi determinado que o proxy da resistividade geoelétrica não é válido para o potencial de retenção de contaminantes condutores.
Der Distrito Federal ist durch eine starke Urbanisierung geprägt. Das ohnehin bereits starke Bevölkerungswachstum wird Prognosen zufolge weiter zunehmen. Der damit verbundene Anstieg des Wasserverbrauchs wird auch in absinkenden Grundwasserständen widergespiegelt. Weiterhin ist das westliche Zentralbrasilien aufgrund seiner Lage in den wechselfeuchten Tropen durch eine starke Saisonalität der Niederschläge geprägt. Das erhöhte Abwasseraufkommen in Verbindung mit extremen Niederschlagsereignissen kann zu einer deutlichen Überbelastung der vorhandenen Kläranlagen führen. In Extremsituationen kann ungeklärtes Abwasser in die Bodenzone gelangen und somit Schutzgüter wie Boden und Wasser kontaminieren. Eine effiziente Maßnahme gegenüber der unkontrollierten Versickerung von ungeklärtem Abwasser sowie zur Vorbeugung absinkender Grundwasserspiegel ist die gezielte Infiltration von vorbehandeltem Abwasser in Verbindung mit einer Grundwasseranreicherung. Diese Maßnahme umfasst einen zusätzlichen Reinigungsschritt des vorgereinigten Abwassers und dient zur Vorbeugung gegenüber absinkenden Grundwasserspiegeln. Ziel der Arbeit war es, geeignete Böden und Flächen für eine Grundwasseranreicherung mit vorbehandeltem Abwasser im Distrito Federal auszuweisen. Zur Identifizierung geeigneter Böden wurden repräsentative Bodenproben auf ihre pedologischen und geochemischen Eigenschaften hin untersucht. Zusätzlich wurden in situ Durchlässigkeitstests und ein Versickerungsmonitoring aufgebaut, um zur Klärung der Infiltrationseigenschaften beizutragen. Für die Laboruntersuchungen wurden die Bodenproben im Hinblick auf ihre Schadstoffrückhaltepotentiale untersucht. Dazu wurden kombinierte hydrochemische und geoelektrische sowie ungesättigte Säulenversuche durchgeführt. Dadurch war es möglich, Rückschlüsse auf die Sorptionsleistung der Böden gegenüber den Abwasserinhaltsstoffen einer künstlichen Abwasserlösung schließen zu können. Die Bodensäulen wurden mit einem künstlichen Abwasser mit bekannter Schadstoffzusammensetzung überstaut. Auf der Grundlage der Bilanzierung aller hydrochemischen Daten wurden die Schadstoffrückhaltepotentiale für die Abwasserinhaltsstoffe berechnet. Anschließend wurden die experimentell ermittelten Parameter in einer Nutzwertanalyse zusammengefasst, um so geeignete Böden für eine effiziente Grundwasseranreicherung mit vorbehandeltem Abwasser zu identifizieren. Abschließend wurden die Feld- und Laboruntersuchungen mit einer GIS-basierten Nutzbarkeitsanalyse komplettiert, um die gemessenen Parameter mit weiteren vorliegenden, räumlich aufgelösten Daten verschneiden zu können. In diese Analyse wurden Parameter wie Gefälle, Landnutzung und Landbedeckung einbezogen. Bei der Auswertung der hydrochemischen Bilanzen kristallisierten sich vorwiegend die jungen Böden aufgrund ihrer hohen Schadstoffrückhaltepotentiale als geeignete Böden für eine Grundwasseranreicherung mit vorbehandeltem Abwasser heraus. Exemplarisch wies der Gleissolo ein Sorptionspotential von fast 100 % für den Parameter TOC auf. Allerdings müssen Böden für eine effektive Grundwasseranreicherung mit vorbehandeltem Abwasser zusätzlich zu den hohen Sorptionsleistungen auch hohe hydraulische Durchlässigkeiten aufweisen. Für den Gleissolo wurde im Feldversuch die niedrigste hydraulische Durchlässigkeit von 1,12 x 10-8 m/s bestimmt. Durch die Einbindung der gemessenen hydraulischen und hydrochemischen Daten in eine Nutzwertanalyse konnten diese Parameter gewichtet werden, um so den Ansprüchen einer effektiven Grundwasseranreicherung gerecht zu werden. Im Ergebnis der durchgeführten Untersuchungen hat sich gezeigt, dass sich die Bodengruppe der Latossole besonders gut für eine Grundwasseranreicherung mit vorbehandeltem Abwasser eignet. Diese Böden weisen die besten Infiltrationsbedingungen sowie gute Sorptionseigenschaften für eine effizient gestaltete Grundwasseranreicherung auf. Mit Hilfe der GIS-basierten Nutzbarkeitsanalyse geografischer Parameter wurden Flächen ausgezeichnet, die sich in Bezug auf Gefälle, Landnutzung/Landbedeckung, Bodentiefe und einer adäquaten Distanz zu Schutzgebieten für eine Grundwasseranreicherung mit vorbehandeltem Abwasser eignen. Zusätzlich wurden die mit Hilfe der Nutzwertanalyse kategorisierten Böden in die Flächenidentifizierung einbezogen. Das Resultat dieser Arbeit liegt in Form einer Karte vor, in der die Gebiete, die für eine Grundwasseranreicherung mit vorbehandeltem Abwasser geeignet sind, nach Kategorien geordnet, verzeichnet sind. Zusätzlich dazu liefert die Arbeit entscheidende Hinweise auf Bodeneigenschaften, die sich positiv auf eine Abwasserinfiltration auswirken. Darüber hinaus konnte durch das geoelektrische 3D-Monitoring und der dabei gemessenen Verteilung des spezifischen elektrischen Widerstandes gezeigt werden, dass die Infiltration gravitativ gesteuert nur die Bodenzone direkt unterhalb der Verrieselung beeinflusste. Weiterhin wurde festgestellt, dass das Proxy des geoelektrischen Widerstandes im Labormaßstab nicht aussagekräftig genug ist, um Rückschlüsse auf die Sorption leitfähigkeitsrelevanter Abwasserinhaltsstoffe geben zu können.