ABSTRACT CHARACTERIZATION OF KIZILCAHAMAM GEOTHERMAL FIELD BY TRACER TESTING Tevfik Kaya M.S, Petroleum and Natural Gas Engineering Department Supervisor : Assoc. Prof. Dr. Serhat Akin Co-Supervisor : Prof. Dr. Mahmut Parlaktuna September 2005, 107 Pages Kizilcahamam Geothermal Field which is 70 km far from Ankara, has been utilized for Geothermal District Heating System, 25 MWt, 2500 residences capacity, greenhouses heating, thermal facilities since 1994. The average production rate is 350m3/h during the heating season , 150m3/h during the summer season for hot water and yearly average reinjection rate is 114m3/h from the field. The long term projections has been studied concerning on expected pressure decline by matching 10 years field history data which contain dynamic level and temperature data. The pressure decline is 140 kPa in the field between 1999 and 2005 with the existing reinjection rate, if the existing rates do not change, the additional pressure decline which is 120 kPa will be occurred up to 2011. In order to get more information from the field, the fluorescein as tracer has been injected in to the MTA-1, and the samples were collected from the MTA-2, Fethi Bey, IHL-1 and IHL-3 for 3 months. The fluorescein concentration has been detected by using fluorimeter, and tracer concentration time plots were analyzed. The fluoreiscein was detected in short breakthrough time in MTA-2 and Fethi Bey which are close to reinjection well, breakthrough time is longer in IHL-1 and IHL-3. The interpretation of tracer test shows that there is communication between all wells. Tracer concentration time plots were compared with different mathematical models, the best match was obtained with multi-fractured model. These results show that Kizilcahamam field is not homogeneous field. It is expected that increasing the reinjection rate will decrease the pressure decline in the field.

No description available.

The Karoo has been receiving considerable attention since the early 1970’s when uranium mining was at its peak, with numerous research studies being instigated to look at all aspects of uranium mining. It has recently been observed that there seems to be resurgence in uranium exploration in and around the town of Beaufort West. A study on the transport mechanisms of uranium and thorium in fractured-rock aquifers, initiated in the hope of understanding the actual processes controlling radionuclide mobilisation, is reported here. Hydrochemical investigations of the various boreholes were sampled for water quality in June, 2009. The hydrochemical description is typical of shallow fresh groundwater, changing composition to a more sulphate hydrochemical facies along the flow path. While the geochemistry of groundwater in the study area seems to have minimal effects on uranium concentrations, the low levels of uranium in boreholes sampled suggest the importance of hydrological and lithological variability on the measured concentrations. Nevertheless, the uranium concentration is within the recommended levels as specified in the US-EPA, WHO and SA water quality guidelines and thus poses no immediate threat to the general public. Analysis of pumping and tracer tests, reveals that the fractured-rock aquifer can be highly transmissive and that transport can take place via multiple flow paths having different hydraulic properties. Tracer diffusing into stagnant water zones within fracture asperities and the rock matrix are seen as an important retardation mechanism, that has implications for remediation should the aquifer be contaminated by radionuclides. In terms of conceptualising flow at a local scale, aperture sizes ranging from (563-828ìm) along with high flow velocities (1.90E-03m/s), points to the importance of bedding-plane fractures as conduits of groundwater flow. The groundwater flow has been influenced by dolerite dykes creating compartments isolated from each other, suggesting a highly complex aquifer system. Based on the conceptual model, it is shown that these structures can create unique, site specific flow conditions. The integration of all available data into the conceptual model provides an effective research tool that can be built upon as a basis for further research. / Dissertation (MSc)--University of Pretoria, 2010. / Geology / unrestricted

Streams and rivers have been modified in the past centuries for agricultural purposes. The Baltic Sea suffers from problems regarding eutrophication. Regulations of point-sources have decreased nutrient levels, but for a scattered source of nutrient pollution, streams are important. One way of mitigating nitrogen is with coupled denitrification and nitrification processes when stream water is transported through flow paths in the hyporheic zone, an area in the stream sediments where groundwater and stream water mix. Tullstorps brook is an agricultural stream that flows into the Baltic Sea. It has had problems with high nutrient loads and poor water quality and has therefore been restored. The fieldwork in this project was conducted in Tullstorps brook in May 2019, where Rhodamine WT (RWT) tracer test and Hydraulic Conductivity (HC) measurements were done in 3 reaches, and compared to similar fieldwork since before restorations, during the summer of 2015. Two reaches in an agricultural setting that have been restored, Reach 4 and Reach 6, were measured, as well as a control reach, Reach 5, which is in a natural setting. The tracer tests indicated a significant decrease in the velocity in remediated reaches. The results of exchange velocity between the stream flow and the hyporheic zone suggest an increase after remediation of the reaches and the residence time seems to be decreasing simultaneously. When comparing the hydraulic characteristics, different stream flow during measurements was considered in a qualitative manner. The results of HC measurements show a decrease from 2015 to 2019 in the remediated reaches. In Reach 4 it decreased from 1.20E-03 m/s to 5.0E-4 m/s and in Reach 6, HC decreased from 7.70E-04 m/s before remediations to 5.6E-04 m/s after remediation actions. All the measurements have uncertainties, especially since homogeneity is assumed to some extent and the natural environment will always be heterogeneous.

Current climate change poses a threat to the Arctic due to increasing temperatures, which cause the permafrost and glaciers to melt and thaw. This thesis focused on analyzing water balances in Tarfala catchment between 2000 and 2020 and using GIS as a support for tracer test results measured in Tarfala in 2021. The results suggest that high resolution DEM data are more useful compared to low resolution DEM when it comes to understanding local hydrology. In addition, analyses regarding tracer test data suggest that permafrost can act both as a hinder and water flow pathway changer in Tarfala. Water balance calculations show that the area is highly affected by snow, permafrost and climate change and may come to change towards wetter and snow and permafrost free conditions due to climate change. / Den pågående klimatförändringen har en markant effekt på det arktiska ekosystemet på grund av de stigande temperaturerna vilket orsakar permafrosttining. Denna uppsats fokuserade på att analysera vattenbalanser mellan 2000 och 2020 i Tarfalas avrinningsområde samt diskutera hur spårämnesförsök och GIS kan användas för att analysera de lokala förhållandena i områden med permafrost. Resultaten tyder på att högupplöst DEM data kan användas som stöd för spårämnestester som påverkas starkt av jordartssammansättningen och permafrost i Tarfalas avrinningsområde. Resultaten tyder också på att vattenbalans i Tarfala påverkas och har påverkats av flera olika faktorer såsom permafrost, snö och klimatförändringar och kan komma att förändras i framtiden till mer våta samt snö- och permafrostfria förhållanden.

Hydraulic fracturing is a controversial practice because of concerns about environmental impacts due to its widespread use in recovering unconventional petroleum and natural gas deposits. However, water-only hydraulic fracturing has been used safely and successfully for many years to increase the permeability of aquifers used for drinking and irrigation water supply. This process extends and widens existing bedrock fractures, allowing groundwater storage to increase. Researchers have studied the behavior of fractured-rock aquifers for decades, but little has been published on the hydraulic and mechanical properties of hydraulically enhanced fractures. In this study, a multi-faceted approach consisting of aquifer and tracer testing is used to estimate the transmissivity and storage coefficient of a hydraulically induced fracture and observe its behavior as a contaminant flow pathway. The results of the aquifer tests indicated a decrease in both the transmissivity and storage coefficient of the fracture of three orders of magnitude after cessation of pumping. The aquifer temporarily experienced incomplete recovery following pumping tests, likely due to slow recharge. After complete recovery occurred, subsequent tests showed that these hydraulic properties returned to their original values, indicating elastic compression of the fracture during periods of applied stress. The results of the tracer test indicated rapid, uniform, one-dimensional flow through the fracture, with average fluid velocity approaching 1 km/day in an induced steady flow field of 6 x 10-5 m3/s (1 gal/min) and a fracture volume of 0.238 m3 (63 gal). The complex heterogeneity of fractured-rock aquifers necessitates the use of multiple lines of testing in order to arrive at a detailed description of the behavior of these systems. This study demonstrates one effective method of investigating a single fracture that can uncover information about the behavior of a hydraulically enhanced aquifer that is otherwise difficult to obtain. / Master of Science

When establishing a groundwater protection area it is of great interest to be able to estimate the transit time of the groundwater from different places of the aquifer to the withdrawal well. These estimates can be uncertain due to heterogeneities in the aquifer. As a part of the work to develop methods for a more certain delineation of protection areas, a tracer test was performed in an esker located 25 kilometres NW of the town Uppsala. The purpose of this master thesis was to perform, describe and evaluate the tracer test. Travel times from the tracer test should then enable comparison against stochastic simulated travel times of the groundwater in the area. Three dyes (rhodamine WT, uranine and naphtionate) and a salt (NaBr) were used in the tracer test. The tracers were injected in four different wells located 25 meters from a pumping well. The pumping well was pumped at a rate of 1.7 L/s and water samples were collected from the pumped water. The calculated mass recovery was large for bromide (101 %) but considerably lower for the dyes rhodamine WT (70 %), uranine (61 %) and Naphthionate (19 %). The low mass recovery for the dyes is probably due to degradation and maybe also adsorption. An analytical solution to the advection – dispersion equation in one dimension for radial converging flow was used for the interpretation of the breakthrough curves. Smallest and largest transit time that was received from the model fitting was 1,9 days and 5,1 days respectively and without exception large longitudinal dispersivities (9-35 m). Point dilution tests were performed in the injection wells in order to determine the ground water flow at these wells. The tests gave information about the magnitude of the ground water flow, differences between the wells and the flow change at pumping. Travel times were estimated from the received breakthrough curves and the travel time distributions can be used for comparison against stochastic simulated travel times of the groundwater. / Vid utformningen av skyddsområden för grundvattentäkter är det av stor vikt att kunna uppskatta grundvattnets transporttid (uppehållstid) från olika partier av akviferen till uttagsplatsen. Dessa bedömningar har en tendens att bli osäkra på grund av heterogeniteter i akviferen. Som ett led i arbetet att utveckla metoder för en säkrare avgränsning av skyddsområden genomfördes ett spårämnesförsök i en isälvsavlagring (Järlåsaåsen) belägen cirka 2,5 mil nordväst om Uppsala. Syftet med examensarbetet var att genomföra, beskriva och utvärdera spårämnesförsöket. Bestämda transporttider från spårämnesförsöket skulle sedan kunna användas för jämförelse med stokastiskt simulerade transporttider för grundvattnet i området. Tre färgspårämnen (rhodamin WT, uranin och naphtionat) och ett salt (NaBr) användes vid spårämnesförsöken. Spårämnena injicerades i fyra olika grundvattenrör belägna 25 meter från en uttagsbrunn. Pumpflödet ur uttagsbrunnen var 1,7 L/s och med en automatprovtagare togs vattenprover från det uppumpade vattnet. Resultatet från massbalansberäkningarna visade på att all injicerad bromid återfanns i uttagsbrunnen, men andelen återfunnen spårämnesmassa var betydligt lägre för färgspårämnena rhodamin WT (70 %), uranin (61 %) och naphtionat (19 %). Den låga andelen återfunnen massa beror troligtvis främst på nedbrytning och kanske även på adsorption. En analytisk lösning till advektions- dispersionsekvationen i en dimension för radiellt konvergerande strömning användes vid utvärderingen av genombrottskurvorna. En minsta och största uppehållstid på 1,9 dygn respektive 5,1 dygn och överlag oväntat stora dispersiviteter (9 – 35 m) erhölls från kurvanpassningen. Den första ankomsttiden till uttagsbrunnen hade ett minsta och största värde på 3,8 respektive 13 timmar. Utspädningsförsök genomfördes också för att bestämma storleken på flödet vid injektionsrören. Dessa försök gav en bild av flödets storlek, skillnader mellan de olika injektionsrören och flödets förändring vid pumpning. De bestämda transporttiderna visar på relativt stora tidsskillnader och ett heterogent försöksområde. Transporttidsfördelningarna utgör också ett underlag för en jämförelse mot stokastiskt simulerade transporttider av grundvattnet.

The Sub artic regions are becoming increasingly important due to the effects of climate change. In northern Sweden, thawing of permafrost has led to significant increases in annual minimum flows in several catchments. This has led to studies of groundwater flow, responses to precipitation and runoff, and subsurface connectivity of springs on slopes. However, there remains a limited understanding of the interplay between surface flow and subsurface flow in the hillslopes of subarctic region. There is a need to better understand the flow pathways and connectivity of groundwater flows within the slopes. This study aims to analyze the interactions between surface flow and subsurface flow on an Sub artic mountainside. Utilizing tracer experiments and a hydrological model, the complex dynamics governing water movement within this intricate system have been studied.  Tracer experiments affirmed the hydraulic connection between hillslope and spring. The spring's response to tracer injection hinted at dominant preferential flow paths within the regolith layer's base. Nonetheless, only 40% mass recovery raised queries about factors affecting the flow in the hillslope. Thus, in this project, a model was developed using Advanced Terrestrial Simulator (ATS) to examine the dominant flow processes and evaluate the influence of various hydrogeology parameters and fluid flow properties on tracer movement. The results highlight the dominance of subsurface flows occurring close to the surface. The parameter sensitivity analysis conducted in the study showed that roughness coefficient and permeability significantly influenced specific pathways and directions that water, and tracers took as they moved through the hillslope's subsurface layers and regolith.  However, the model has limitations, such as neglecting the lateral variations of the subsurface material, seasonal freeze-thaw processes and the simplified representation of the slope and catchment. The results of this study show the need for utilizing more field-based methodologies and further refinement of the modeling approach to improve our understanding of hydrologic processes in high latitude areas.

No description available.

Les milieux aquifères karstiques représentent des ressources en eau importantes, particulièrement sur le pourtour méditerranéen où ils constituent la majorité des réservoirs d'eau douce souterraine. La demande en eau ayant littéralement explosée au cours de ces dernières années, ces ressources en eau constituent un facteur limitant du développement, à l'origine de conflits d'aménagements et d'usages. Il est donc nécessaire d'avoir une meilleure connaissance de ces milieux afin de proposer une exploitation appropriée, répondant aux besoins régionaux. Toutefois, ces milieux restent encore mal connus, notamment à cause de la difficulté à caractériser leur fonctionnement inhérent à l'hétérogénéité organisée de leurs écoulements. Afin d'améliorer la connaissance de ces milieux, nous avons réalisé une étude détaillée des propriétés hydrologiques de l'aquifère karstique du Lez situé en région Nord Montpelliéraine. La source du Lez alimente en eau potable la région par des pompages dans le conduit principal du réseau de drainage. Le bassin (d'une superficie d'environ 200 km²) est équipé d'un réseau dense de piézomètres, ainsi que d'un site expérimental, situé à 4.5 km au nord de la source du Lez concentrant une vingtaine de forage sur une superficie d'environ 1500 m². Ce travail porte à la fois sur 1) une caractérisation multi-échelle de l'hétérogénéité des propriétés hydrodynamiques du système, et 2) une étude du transfert de masse au sein du réservoir via analyse de traçages artificiels réalisés à l'échelle régionale et à l'échelle du site expérimental. Dans un premier temps, les essais en puits seul ont permis caractériser les différents éléments du karst et d'identifier les structures les plus transmissives. A l'échelle du site expérimental, l'analyse de l'essai de pompage a mis en évidence une connectivité globale liée à l'interface stratigraphique et une hiérarchisation des écoulements dépendante de la fracturation verticale. Enfin, l'étude des interférences des pompages du Lez à l'échelle régionale indique une compartimentation hydraulique du système. Les propriétés hydrodynamiques estimées dépendent de l'hétérogénéité structurale et des conditions hydrologiques du bassin. Le recoupement de ces différentes analyses permet une discrétisation des paramètres hydrauliques des composantes structurant les écoulements au sein d'un massif karstique. L'étude du transfert de masse à l'échelle locale et régionale complète cette caractérisation et renseigne les propriétés de transport du réseau karstique. Les essais de traçage à l'échelle du site mettent en évidence la forte hétérogénéité du milieu avec des chemins d'écoulement multiples induisant un gradient de vitesse. Tandis qu'à l'échelle régionale une corrélation des vitesses d'écoulement est observée au sein du réseau de drainage principal.L'ensemble de ces résultats fournit une meilleure connaissance à différentes échelles des propriétés et de la vulnérabilité de ces milieux complexes, constituant une base essentielle pour une modélisation hydrodynamique multi-échelle de ce type d'aquifères. / Characterizing groundwater flows in karst aquifers at different scales of space and time, is not an easy task due to the high level of heterogeneity of these aquifers. Because the limited testing radius of classical hydraulic methods (slug tests, pumping tests), the regional hydraulic parameters of karst systems are generally estimated using the flow recession analysis method. But this integrative method generally does not give a differentiation into regionally varying parameters. Also, it is generally difficult to gather enough data to characterize aquifer heterogeneities at regional scale. For this reason, most of studies about hydrodynamic characterization of karst aquifer focus on local scales, i.e experimental field site scale or borehole scale; measurements at small scale could then be upscaled to obtain hydrodynamic parameters at regional scale. Consequently, understanding scale dependence of groundwater flows organization in such a context is of prime importance for the development of regional scale model.In this study, the monitoring of groundwater flow and transport is performed at several scales of time and space, within a single Mediterranean karstic carbonate aquifer, the Lez karst aquifer, located South of France. Groundwater is intensely pumped in a karst conduit upstream of the main karst outlet (Lez spring), for regional water supply. At regional scale, the relatively dense groundwater monitoring network permits to determine the hydrodynamic properties of the aquifer inferred from the hydrodynamic response to pumping at the Lez spring. At the scale of the experimental field site (Terrieu site), that comprises 22 boreholes, several experiments (i.e. pumping tests, packer tests, slug and injection tests) were performed to determine the hydrodynamic properties at experimental field site scale and borehole scale. Tracer experiments were also performed to provide an estimation of transport properties both at the scale of the experimental field site and at regional scale.The hydrodynamic properties estimated at different scale of space and time (for different hydrological conditions) were compared with flow paths organization linked to the geological structure of the reservoir. At regional scale both the hydrological conditions (i.e. high or low water level) and geological compartmentalization that impact the hydraulic connectivity, control the hydrodynamic properties. Tracer experiments revealed short time transfer and high connectivity between injection points and the spring. At the experimental field site scale, pumping and tracer test highlighted heterogeneous flow pattern that can be linked to the position of boreholes and the main geological features. At borehole scale, hydraulic tests revealed a high range of hydrodynamic properties (transmissivity from 10-11 m²/s to 10-2 m²/s) depending on the investigated part of the aquifer (matrix, fracture or drain).Depending on the water level conditions, the aquifer presents variable organization of flows that modify the hydrodynamic parameters. As expected, variability of hydrodynamic parameters depends on the scale of investigation: a difference of 10 to 105 has been quantified for a same parameter characterized at borehole scale and at regional scale. This hydrogeological parameters quantification of karst system provides important constrain about multiscale modeling using conceptual models to represent the characteristics of the main flow paths.