A catchment model, which has the objective of simulating streamflow and calculating groundwater recharge of a small undeveloped catchment «100 km2), is described. The model accepts input daily data of rainfall and potential evapotranspiration, and it consists of two parts. Firstly, the modified Stanford Model to simulate the land phase processes, and secondly the Penman-Grindley soil moisture balance to calculate recharge. Several assumptions have been made so that the model can be applied on a rural catchment from which rainfall data is routinely collected on a daily basis. In order to estimate recharge accurately the volumes of interception and surface runoff have to be estimated first. This is done by the modified Stanford Model. The root constant parameter in the Penman-Grindley soil moisture balance provides a realistic formulation for recharge calculations. The root constant is easily estimated from the crop cover and hence can be used to simulate the effect of changing land use on the hydrologic regime. The model has been developed on a small catchment (63 km 2 ) of the River Bain above Goulceby in East Lincolnshire. Simulation of streamflow is indicated to be more accurate in the low- to medium flow ranges than in the high flow range. Although the time step of one-day adopted in the rr.odel is sufficient for accurate calculation of recharge, it is not sufficient for accurate simulation of surface runoff which characterises the high flow events. In addition to simulation of recharge and streamflow, the model can also be used to study the effect of variation of certain parameter on the hydrologic regime.

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We consider a simple semi-empirical scoping calculation in conjunction with mathematical models to estimate the radius of impact (Ri) and to determine the circumstances under which gold mines in Ghana are likely to have adverse effect on water levels and volumes in surrounding villages/farms. The approach involves the assessment of local mine geometries, collation and examination of hydraulic conductivity data and the assessment of recharge infiltration rate. Most of the models used with the entire conductivity dataset (Group A) predicted very close radius of impacts to mine with less than few 100m with a median distance of 400m from the mine’s edge. Although it is expected that 25% of cases could reach up to 2km and further if the system was anisotropic. Derogation of water level and volume is more of a problem for Group B and C aquifer systems of higher conductivity values. Model results show that 50% of cases could reach up to 3.6km with a range of 2.7km to 5.1km, and 3km with a range of 2km to 4.6km from mine centre respectively. Nevertheless, Ri could reach 7.6km and further in extreme cases if the system was anisotropic. With regards to Ghana, by constraining conductivity values using water volumes produced by mines in Ghana, and comparing with the model output, it is tentatively suggested that the most likely Ri values are those calculated with the Group B dataset. It should, however, be noted that this results are very sensitive to hydraulic conductivity, and therefore there is the need in Ghana to publish conductivity and volume data to enable suggestions from this work to be confirmed.

Groundwater (GW) -fed streams are a common feature of paraglacial floodplains and are regarded as ‘biodiversity hotspots’, due to their role as valuable aquatic habitats. The hydrological dynamics which support GW-fed streams remain poorly understood. There is a need to improve understanding given paraglacial environments are extremely sensitive to the impacts of climate change. To address this significant knowledge gap site specific research was conducted on GW-fed streams within Denali National Park & Preserve, Alaska, during 2013 and 2014. Hydrometric, hydrochemical, hydrogeomorphic, and geophysical techniques were utilised to improve understanding of the hydrological dynamics and hydrogeomorphic controls that influence GW-fed stream occurrence. Paleochannels across paraglacial floodplains were identified as important preferential flow pathways (PFPs); and a first-order control upon GW-fed streams. In addition hillslope-runoff was established as an important hydrological flux to GW-fed streams. Colluvial deposits (e.g. talus cones) were highlighted as valuable hydrological stores on valleys-sides that made a direct contribution to streamflow. This research has raised concerns about the long-term stability of GW-fed streams in paraglacial environments due to changes in hydrogeomorphic controls (PFPs). It has also raised more immediate concerns about the short- to medium-term implications of shifting hydrologic regimes (e.g. declining winter snowpack) for GW-fed streams.

This thesis presents studies of the heterogeneous nature of groundwater-surface water (GW-SW) interactions at the hillslope and catchment scale in the 3.2km2 Bruntland Burn, UK. GW fluctuations were measured within three contrasting hydropedological units. Synoptic hydrogeochemical surveys were carried out (major ions, stable isotopes) to capture the increased influence of GW to the stream during a 10year return period drought. The catchment was shown to have highly dynamic GW stores, with each landscape unit translating into different rainfall-runoff processes. Soil characteristics were shown to be the strongest predictors for variability in GW dynamics. Each soil type was characterised by a unique storage-discharge relationship and threshold response with a certain GW level above which lateral flow dominated. On the lower hillslope, predominating lateral flow and little recharge to depth is supported by hydrologically responsive soils. Connectivity between the steeper slopes and the valley bottom, however, needed persistent wet periods to overcome storage thresholds. Here, vertical flow paths recharging deeper GW dominated, with GW levels falling below the soil layer into the underlying drift. It was found that relatively well mixed, near-surface sources of stream flow predominated in wetter conditions, whilst baseflows are variable and reflect a diverse range of GW stores. Geophysics (ERT) and GW level measurements were integrated into MODFLOW-NWT to simulate GW-SW interactions along a representative 2D-hillslope transect. Although only a preliminary model, it was shown that shallow pathways have much shorter residence times, thus maintaining high water tables in the riparian peatlands, than deeper flow paths discharging through the drift and directly into the stream. Largest sources of GW are located within the drift, resulting in complex spatial patterns of runoff generation. This work illustrated the utility of a basic model to predict GW flow paths, highlighting how water and solutes are stored and released in montane headwater catchments.

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Orientadora : Ernani Francisco da Rosa Filho / Co-orientador : André Virmond Lima Bittencourt / Co-orientador : Donizeti Antonio Giusti / Dissertaçao (mestrado) - Universidade Federal do Paraná / Resumo: O aqüífero Carste está situado na parte norte da Região Metropolitana de Curitiba. A identificação, neste aqüífero, de uma unidade compartimentai com características hidrogeológicas próprias, a qual possa ser extrapolada para o todo, possibilita ao estabelecimento de uma política de uso sustentado e proteção ambiental do mesmo. A proteção e gerenciamento adequado do aqüífero, depende da redefinição da unidade planejamento urbano para a Região Metropolitana de Curitiba, estabelecendo o meio físico como parâmetro de planejamento em substituição à bacia hidrográfica. Até o presente momento, os planos diretores para abastecimento público da cidade de Curitiba e arredores, são fundamentados na utilização de mananciais superficiais, em franco processo de degradação. Uma nova alternativa aventada é o uso do aqüífero carste, com melhor qualidade e menores custos, carecendo no entanto de uma metodologia adequada para o seu estudo. O aqüífero cárstico apresenta uma relação direta com a existência de rochas carbonáticas com grande capacidade de dissolução, representadas pelos mármores. A massa carbonática é condicionada entre délimitantes impermeáveis representadas por cristas de filitos e quartzitos segundo direção preferencial NE-SW e diques de diabásio com direção preferencial de NW-SE. Os diques secionam transversalmente as cristas, originando assim um padrão de unidades losangulares com comportamento hidrogeológico similar entre si. Em cada unidade, afloram dois tipos de rochas, respectivamente rochas carbonáticas e rochas silicatadas, com diferentes aptidões quanto ao uso e ocupação do solo. As zonas de recarga e descarga do aqüífero situadas na área das rochas carbonáticas apresentam maiores a restrições quanto ao uso do que a área das rochas silicatadas. O manejo hídrico combinado das águas superficiais e subterrâneas é possível no compartimento, devido ao caráter impermeável das limitantes e a recarga artificial do mesmo pode promover sua regularização, durante os períodos de superávit hídrico. As vocações naturais de uso para a área do aqüífero Carste são o potencial do manancial subterrâneo para abastecimento público, mineração de calcário, uso agrícola e eco-turismo. Não são recomendados nesta área o acentamento urbano em altas concentrações. / Abstract: Karst aquifer is situated in the north part of Curitiba Metropolitan Area. The identification in this aquifer, of a compartment unit with its own hydrogeological features, that can be extrapolated to the whole area, allow the establishment of a sustainable use and environmental protection policy for the area. An adequated aquifer management and protection, depends on a redefinition of the urban planning unit in Curitiba Metropolitan Area., establishing the physics aspects of the area as a planning parameter, instead the hydrographic basin. Up to now, the master plans of water for public supply to the city of Curitiba and surrounding areas, are based in the surface waters utilization, which are facing high process of environmental degradation. A new alternative is the use of the Karst aquifer, with better water quality and lower costs, but requiring a representative methodology for its study. Karst aquifer is directly related with the existence of highly soluble carbonate rocks, represented by marbles. Carbonate mass is conditioned between impermeable boundaries represented by filite and quartzite crests according to preferential direction NE-SW and NW-SE for a diabase dykes. Dykes cross transversely the crests, resulting in a losangular pattern units with similar hydrogeological aspects. In each unit, we can identify two main lithology the carbonate and silicate rocks, with different ability for the land use and occupation. Aquifer recharge and discharge zones located in carbonate rocks requires more use restriction than the silicated rocks area. Combined surface and ground water hydrical management, is possible in the compartment due to the impermeably of the boundaries and aquifer artificial recharge during the rainy seasons, could promote its regularization. The natural use ability of Karst aquifer area is the ground water potential for public supply, agricultural use, marble mining, ecoturism. The establishment of high urban concentration at this area is not recommended.

The purpose of this study was to investigate the levels and quality of groundwater in a farming area to the north of Doha, the capital of the State of Qatar. Two rows of about five wells were selected, the lines being more or less parallel to each other, about 30 km apart, running for 45 km inland from the east coast. Vertical electrical sounding surveys were undertaken and groundwater samples were taken from these wells in winter and in summer. The water was chemically analysed, and the results formed the basis for a hydrogeochemical modelling exercise. The results of the geophysical and geochemical surveys indicate that there is a seasonal vertical and lateral migration of the fresh water/salt water interface in winter before the rainfall replenishes the groundwater aquifers. The geochemistry of the groundwater indicate that there is a gradual decrease of cations and anions, particularly Na+, cr, S04, and HC03-, together with a decrease in conductivity CEC), total dissolved solids (TDS) and sodium absorption ratio (SAR) from the coast inland. There is an upconing which brings the saline water to the surface near the middle of the southern profile in both seasons. In both profiles the fresh water/salt water interface migrates inland due to the excessive extraction of fresh water from the wells.

This thesis describes the flow of ground water with a free water table, in an isotropic and homogeneous soil overlying a horizontal impermeable layer, from a surface-applied rainfall or irrigation supply to a system of horizontal tube drains. The idealized representation of this situation is in terms of a potential flow towards line sinks. The tube drains (sinks) may be at atmospheric pressure (free flow) or under back-pressure (submerged flow). After describing the flow to systems of drains at uniform depth and equal spacings, the thesis shows the effect of horizontal, vertical and combined misalignments of a single line sink on the free surface, the flow pattern and the rates of flow to each sink. The study was carried out by viscous-flow and electrical analogues, by a numerical method (Relaxation), and by the exact solution of equations based on physical approximations. In theory the extent of the effect of any misalignment is infinite. Experimentally it was found that the vertical misalignment had a significant effect on the free surface, discharge and flow net over the whole range of the experiment, while the horizontal one had a noticeable effect only extending over one spacing on either side of the misaligned drain. An approximate mathematical solution for the horizontal displacement has been obtained. Experiments on the viscous-flow model revealed the importance of the effect on the free surface etc. of the back pressure. The distribution of the effect along the free surface and the correlation between the free surface height and the back pressure are also presented. A new approach was used to elucidate the effect of negative pressure (capillary rise) on the free surface and obtain the surface of atmospheric pressure. An equation, independent of the geometrical scale ratio was derived to relate the various parameters for the unsteady flow to the scaling laws. The introduction of a reference potential at a fixed point in the field provides a method for the correction of the change with time in the position of equipotentials and represents a new technique. The variations of free surface heights with discharge, as observed on the viscous-flow model, were compared with the results of s some recent theories and showed discrepancies between the experiment and theories.

Στην παρούσα μεταπτυχιακή διπλωματικής εργασίας παρουσιάζονται τα αποτελέσματα της έρευνας που πραγματοποιήθηκε σχετικά με την προέλευση και το μηχανισμό γένεσης των θερμομεταλλικών εμφανίσεων της δυτικής Πελοποννήσου. Μετά από υδρογεωλογική και υδροχημική μελέτη των κυριοτέρων πιθανών θερμομεταλλικών εμφανίσεων, αναγνωρίστηκαν ως θερμομεταλλικές πηγές οι πηγές του Καϊάφα, της Κυλλήνης, του Βρομονερίου και του Κουνουπελίου. Οι παραπάνω πηγές έχουν γενικό υδροχημικό τύπο Na-Cl και είναι πλούσιες σε H2S, το οποίο προέρχεται κυρίως από διαδικασίες αναγωγής των θειικών ιόντων. Οι θερμομεταλλικές εμφανίσεις σχετίζονται με την τεκτονική, καθώς δημιουργούνται από μετεωρικό είτε θαλασσινό νερό, το οποίο κατεισδύει σε μεγάλα βάθη και στη ανέρχεται στην επιφάνεια δια μέσω ρηγμάτων. Σύμφωνα με τα αποτελέσματα των ισοτοπικών αναλύσεων, τα θερμομεταλλικά νερά από τις πηγές του Καϊάφα, το Βρομονέρι και την Κυλλήνη έχουν μετεωρική προέλευση. Αντίθετα η πηγή στο Κουνουπέλι έχει μεικτή προέλευση 60% μετεωρικού και 40% θαλασσινού νερού. / In present postgraduate diplomatic work are presented the results of research that were realised with regard to the origin and the mechanism of genesis of genesis of thermal waters in western Peloponnese. After the hydrogeological and hydrochemical study of the main thermal springs, they were recognized as thermal and mineral waters the samples from Kaiafa, Kyllini, Vromoneri and Kounoupeli. These waters have general hydrochemical type Na-Cl and they are rich in H2S, as a result, from the reduction of sulphate ions under suitable conditions. The thermal appearances of Western Peloponnese are related with the infiltration of meteoric or sea water in great depths and their amounted in surface via major faults. According to the isotopic data the springs of Kaiafa, Kyllini and Vromoneri have meteoric origin. On the contrary the Kounoupeli’s spring is a mixed water (60% meteoric water and 40% sea water).