Philosophiae Doctor - PhD / The analysis of geologic, hydrologic and hydrogeologic data interpreted to give the characteristics of the Cape Flats aquifer showed the quality of groundwater from the aquifer is suitable for development as a water resource. The conceptual model of the Cape Flats sand shows an unconfined sandy aquifer, grading into semi-confined conditions in some places where thick lenses of clay and peat exists. Recharge rates through the saturated zone of the Cape Flats aquifer have been determined by water table fluctuation (WTF), rainfall-recharge relationship, soil water balance and chloride mass balance methods (CMB). Recharge rates using the WTF vary considerably between wet and dry years and between locations, with a range of 17.3% to 47.5%. Values obtained from empirical rainfall-recharge equation (method 2) agree with those of the WTF. Recharge estimates from the water balance model are comparatively lower but are within the range calculated using empirical method 2 (i.e. 87 - 194 mm or 4 – 21% of MAP). These recharge rates also agree with estimates from the series of other methods applied to sites located in the north-western coast of Western Cape and are comparable to recharge rates obtained elsewhere in the world. / South Africa

The activity of mineral extraction in the Valley of Paraíba do Sul River occurs in a vulnerable environment and is responsible for environmental impacts on the alluvial plain. When this activity is developed without technical criteria a predatory exploration results, generating changes in the environment and raising questions from the concerned community. Since 1993, several methodologies to recover degraded areas were proposed to minimize the impacts of the extraction of sand. Some produced positive results and others failed. This work had the objective to create a data basis in a Geographic Information System to evaluate the degree of impact of the activity of sand extraction in the alluvial plain of the Paraíba Valley, in the segment between Jacareí and Pindamonhangaba, for the period from 1992 to 2003 and to give support to licensing, monitoring of the environmental law enforcement and control of the activity of sand mining. Using the software SPRING and Landsat imagery, ETM+ scenes 218/76 and 219/76, a georeferenced database was created for production of maps and quantification of sand extraction areas. The use of images of different acquisition dates made it possible the assessment of the evolution of the activity in the area. Field work allowed the comparison of results from the two methods for degraded areas recovery, i.e. eforestation and natural regrowth. Using data from the weather station of the Department of Agrarian Sciences of the University of Taubaté and an EXCELTM spreadsheet, the climatological water balance and the potential evapotranspiration were calculated to estimate the amount of evaporation from the water surface left by the sand extraction process. Thus, it was possible to estimate the impact of water loss to the atmosphere due to this activity. The data basis integrated in a GIS platform developed in this work represented a technological advancement for the control actions and fiscalization and allowed the assessment of the area expansion and the impact of the loss of water for the atmosphere due to evaporation due to sand mining. / A atividade de extração mineral no Vale do Paraíba do Sul, praticada em um ambiente vulnerável, é responsável por alterações ambientais na planície aluvial. Essa atividade quando conduzida sem critérios técnicos se constitui numa exploração predatória e gera alterações no Meio Ambiente e pressões por parte da comunidade. Desde 1993, várias etodologias de recuperação de áreas degradadas foram propostas para minimizar os impactos da extração de areia. Alguns produziram resultado e outras não. Esse trabalho teve por objetivo criar um banco de dados baseado em um Sistema de Informações Geográficas para se avaliar a evolução e o grau de interferência da atividade de extração de areia na planície aluvial do Vale do Paraíba, no trecho entre Jacareí e Pindamonhangaba, no período de 1993 a 2003 e, dar suporte ao licenciamento, fiscalização e controle da atividade de mineração de areia. Utilizando-se o software SPRING e imagens do satélite Landsat sensor ETM+, cenas 218/76 e 219/76, produziu-se um banco de dados georreferenciado para produção de mapas e quantificação da área ocupada pela extração de areia. A incorporação de imagens de diferentes períodos possibilitou acompanhamento da evolução da atividade na região. Avaliações em campo permitiram a comparação dos resultados obtidos na recuperação de áreas degradadas com revegetação e regeneração natural. Utilizando-se os dados da estação climatológica do Departamento de Ciências Agrárias da UNITAU e uma planilha desenvolvida em ambiente EXCELTM, foi calculado o Balanço Hídrico Climatológico e a estimativa de evapotranspiração potencial, utilizada para se estabelecer a evaporação causada pelas cavas de areia resultantes da mineração. Dessa forma, com a área total de lagos artificiais obtidas do banco de dados georreferenciado foi possível calcular o volume de água perdido para atmosfera por evaporação e a relevância dessa perda no Balanço Hídrico da Bacia Hidrográfica do rio Paraíba do Sul. O SIG produzido a partir deste trabalho representou um avanço tecnológico para as ações de controle e fiscalização; possibilitando conhecer quantitativamente a evolução da área minerada, e avaliar o impacto da perda de água para a atmosfera por evaporação.

Vernal pools are small, ephemeral wetlands lacking an inlet or outlet. These wetlands, also known as seasonal pools, are found in a wide range of biomes, and their characteristics vary based on location. While the vegetation of western U.S. pools, and amphibians of eastern U.S. pools have been extensively studied, many aspects of vernal pools have not been fully characterized. In particular, although the general seasonal wetting and drying cycle is understood qualitatively, few studies have attempted to quantify the hydrological regime of vernal pools in New England. As water level variation drives many, if not all, of the characteristics unique to these systems, more research on this aspect of vernal pool functioning is needed. The primary objective of this study was to gain a better understanding of vernal pool hydrology through the study of a complex of three pools in South Deerfield, MA. The water level in the South Deerfield pools has been monitored since 2009. For this study, the most recently recorded water year (1 October 2017 to 30 September 2018) was used to characterize the water level fluctuations in the Middle Pool. Water level was monitored manually (weekly intervals) and with pressure transducers (4-hour intervals) in permanently installed wells. The effects of precipitation and evapotranspiration on water level were quantified with a water balance analysis. This analysis also estimated changes in storage by estimated inflow from the uplands and outflow via deep seepage. Water level changes in the Middle Pool were consistent with qualitative descriptions and trends described in earlier studies in the region. We found that the countervailing effects of precipitation and evapotranspiration were the primary drivers of water level fluctuations throughout the year. However, the estimate of storage derived as a water balance residual was not representative of water level in the vernal pools. The storage estimate derived for the Middle Pool was more successful at estimating the water level during spring transition, the high water period most important to amphibian breeding.

Summary: Great Podkrusnohorska spoil heaps in the Sokolov region in Western Bohemia is the largest spoil heaps in the Czech Republic, which was pour million tonnes of overburden soil surface mining of brown coal. The thesis is setting on the basic characteristics of the water regime and water balance of spoil heap soil and thus follows a series of previous works dealing with the comparative development of the reclaimed and unreclaimed area. The areas are long-term monitoring of soil moisture using a dielectric soil moisture meter total water regime was monitored by subsurface with gravitation lyzimeter, runoff and throughfall rainfall. Older unreclaimed plots as well as reclaimed plots have higher porosity, water field capacity and moistre than young sites, however there are limited by water deficiency in similatr way as young sites due to increase in wilting point. Keywords: Spoil heaps, Recultivation, Soil humidity, Water supply, Water balance

Le travail de cette thèse s'inscrit dans le cadre du projet MAISEO qui associe, entre autres partenaires, la CACG, gestionnaire de l'eau sur des bassins hydrographiques du Sud-Ouest, Météo-France et le CESBIO. Un des objectifs est de proposer des méthodes innovantes et opérationnelles pour l'estimation des besoins en eau des cultures à l'échelle d'un territoire. Il s'agit de fournir au gestionnaire des outils qui lui permettront de mieux gérer la demande en eau d'irrigation liée à la culture dominante présente dans le Sud-Ouest de la France: le maïs. L'objectif de la thèse consistait à estimer les rendements et les besoins en eau du maïs sur de grandes surfaces. Pour cela, nous avons utilisé un modèle agro-météorologique couplé à l'imagerie satellitaire optique. De nombreuses images à haute résolution spatiale et temporelle provenant de différents capteurs ont été utilisées, préfigurant l'arrivée des données Sentinel-2 lancé en 2015. Il s'agissait dans un premier temps de coupler les données satellitaires avec le modèle SAFY (Simple Algorithm For Yield estimates, Duchemin et al., 2008a), qui simule le développement des plantes en se basant sur la théorie des efficiences (Monteith, 1972), afin d'estimer la biomasse et le rendement du maïs. De nombreuses données terrain ont permis de valider les sorties du modèle. A l'échelle régionale, les résultats ont été agrégés et comparés aux statistiques départementales Agreste. Les résultats ont conduit à proposer une nouvelle version du modèle SAFY permettant de prendre en compte la variation temporelle de l'efficience de conversion de la lumière effective (ELUE) et de la surface spécifique foliaire (SLA). Cette modification permet une meilleure prise en compte de la dynamique de croissance de la végétation et une amélioration de l'estimation du rendement tant à l'échelle locale que régionale. La méthode de calibration a également été améliorée afin de limiter le recours aux données in situ difficilement accessibles sur de grandes surfaces. Nous avons pu mettre en évidence l'apport de la double logistique, utilisée pour interpoler les profils temporels de NDVI. Cette interpolation a permis d'affiner la délimitation du cycle cultural et de contraindre plus précisément certains paramètres du modèle comme la date de levée. Une fois contraint par les données satellitaires, le modèle SAFY est capable de reproduire les rendements sur les deux départements avec une bonne précision et ce sans prendre en compte l'évolution du stock d'eau dans le sol (Battude et al., 2016) / This Ph.D. thesis is part of the MAISEO project associating partners among them: the CACG, managing the water supply of several watersheds located in the south west of France, the Meteo-France center and the CESBIO. One of the goals is to develop innovative and operational tools to estimate crops' water needs at the territory scale. The aim is to provide managers tools to better manage the water supplies linked to the predominant crop encountered in south west of France: maize. The objective of the thesis was to estimate the yield and water requirements of maize crop over large areas. For this purpose, we used an agro-meteorological model coupled to optical satellite imagery. Numerous high spatial and temporal resolution images from different sensors have been used, prefiguring the arrival of the Sentinel-2 data launched in 2015. The first part was to combine remote sensing data with the SAFY (Simple Algorithm For Yield estimates) crop model (Duchemin et al., 2008a) that simulates plant development based on Monteith theory (Monteith, 1972) in order to accurately estimate maize biomass and yield. Numerous field data have been used for the validation at local scale. At regional scale, the results have been aggregated and compared to Agreste yield statistics provided by the French government. Results led us to propose a new formulation of the SAFY model taking into account the temporal variation of the effective light use efficiency (ELUE) and of the specific leaf area (SLA). This modification allows a better simulation of the crop growth dynamics and an improvement of yield estimates at the local and regional scale. Furthermore, we changed the calibration method in order to limit the use of in situ data that are difficult to access over large areas. We also highlighted the contribution of the double logistic function, used to interpolate the NDVI time series. This interpolation enables an accurate determination of the crop growing season and it allows constraining some model parameters such as the emergence date. The SAFY model constrained by remote sensing data is able to well reproduce the yield for the two departments without taking into account the evolution of the soil water storage (Battude et al., 2016)

付記する学位プログラム名: グローバル生存学大学院連携プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21057号 / 工博第4421号 / 新制||工||1687(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 寶 馨, 教授 田中 茂信, 准教授 佐山 敬洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Southeast Australia have between 1997-2009 experienced a severe drought, referred to as the Millennium Drought. During these years the region experienced a 11.4% decline in mean annual rainfall, an unprecedented decrease in runoff and a decline in soil moisture and groundwater storage. The drought officially ended in 2010 when one of the strongest La Nina-events on record occurred. However, it is still unknown how the behaviour of the catchments changed during the drought and if this change persists in the years following the drought. Changes in catchment behaviour and fluxes are commonly determined using a catchment water balance, where the change in groundwater storage is assumed to be neglectable when studying longer periods of time. However, studies have showed that this assumption might be inaccurate for catchments that experience a climatic disturbance such as a severe drought. This study investigates if including the change in groundwater storage by using spatial groundwater head data can improve the catchment water balance. This was done by assuming that specific yields are unknown and to be determined in a calibration. An unknown scalar applied to the evapotranspiration was used to try to account for the uncertainties in the known fluxes and was also to be determined in the calibration. Two different calibration schemes were considered: one assuming no delay in groundwater head response to climate and one accounting for the delay. The fluxes were determined for the period before, during and after the drought. The results were analysed to determine if the catchments showed a change in behaviour during and after the drought. The results showed that when not accounting for the delayed response of the groundwater head, at least one of the specific yields in the catchments became infinitely small. Including the delayed groundwater head response did improve one of the catchments significantly by producing plausible specific yields for all geological units. A conclusion of this is that including the change in groundwater storage could improve the water balance. However, for it to do so a thorough analysis of the groundwater and subsurface needs to be conducted. Further, the water balance error was the third biggest flux after rainfall and actual evapotranspiration suggesting that the evapotranspiration scalar reduced the actual evapotranspiration too much. All fluxes did decrease during the drought, by how much differed between the catchments and the water balance components. Two of the catchments showed a change in behaviour during the drought that persisted in the years following the drought. The most likely fluxes to have caused this were the change in runoff and groundwater storage. The other two catchments showed a smaller change in behaviour during the drought and an indication that it was on its way back to the same state as before the drought. The likely fluxes to have caused the small change in behaviour was runoff and actual evapotranspiration. / Under åren 1997–2009 minskade den genomsnittliga årliga nederbörden över sydöstra Australien med 11.4% och den genomsnittliga årliga avrinningen var lägre än någonsin tidigare samtidigt som grundvattennivåerna sjönk. Denna torka brukar kallas the Millennium Drought och är den svåraste torkan i Australien i modern tid. Torkan tog officiellt slut 2010 då ett av de mest kraftfulla La Niña-fenomenen inträffade vilket bidrog till att april 2010 till mars 2012 var de blötaste två åren i australiensk historia. Trots att flera studier har gjorts kring torkan så är det ännu inte klarlagts hur avrinningsområdena i området påverkades och om de fortfarande är påverkade när torkan officiellt är över. Flödena inom ett avrinningsområde bestäms vanligtvis genom en vattenbalans. Då vattenbalansen över ett avrinningsområde studeras under en längre tid antas ofta att förändringarna i grundvattenmagasinen går att bortse från då grundvattennivån ofta återgår till samma stadie efter ett antal år. Nyare studier har dock visat att detta inte alltid är fallet vid exempelvis en svår torka och att det vid dessa fall inte är korrekt att anta att förändringen i grundvattenmagasinen är försumbar. I denna studie har en vattenbalans gjorts för fyra avrinningsområden i delstaten Victoria i Australien. Syftet har varit att avgöra om vattenbalansen kan förbättras om förändringen i grundvattenmagasinen inkluderas. Detta har gjorts genom att använda nyligen framtagen data för grundvattennivån i delstaten och antagit att den dränerbara porositeten är en okänd variabel. För att justera för osäkerheterna kring the kända flödena har en okänd faktor för evapotranspirationen inkluderats. De okända variablerna bestämdes i en kalibrering. Kalibreringen genomfördes för två olika kalibreringsscheman och för tre olika tidsperioder. Det ena kalibreringsschemat antog att grundvattnet direkt reagerade på effektiv nederbörd minus avrinning, medan den andra kalibreringsschemat tog hänsyn till en försenad reaktion. Kalibreringen gjordes för tidsperioderna innan, under och efter torkan. Resultaten visade att när ingen hänsyn togs till en eventuellt försenad reaktion av grundvatten så går värdet för dränerbar porositet i minst en geologisk enhet mot noll medan det andra värdet är rimligt. När hänsyn togs till en försenad reaktion av grundvattnet, fick fler avrinningsområde rimliga värden för dränerbar porositet för hela området. Slutsatsen som kan dras kring detta är att vattenbalansen kan förbättras om förändringen i grundvattenmagasinen inkluderas. Detta kräver dock en djupgående analys av grundvattnet och geologin i avrinningsområdet. Hur mycket flödena förändrades under och efter torkan varierar mellan avrinningsområdena och flödena, gemensamt var dock att alla flöden minskade under torkan. Två av avrinningsområdena påvisade en förändring i beteendet under torkan och de år som följde. Det är mest troligt att förändringarna i avrinning och grundvattenmagasinen har påverkat detta. De övriga två avrinningsområdena påvisade även de en förändring under torkan, om än mindre än för de föregående. Denna förändring ser även ut att vara på tillbakagående och att avrinningsområdet inom en snar framtid skulle kunna ha samma tillstånd som innan torkan. De mest troliga flödena som har påverkat dessa avrinningsområden är förändringar i avrinning och den faktisk evapotranspirationen.

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Fyllningsdammar har alltid ett naturligt läckage då jordmaterialet som används har en viss permeabilitet. Detta acceptabla naturliga läckage är viktigt att övervaka för att kontrollera att läckageflödet håller sig inom förväntade värden. Om läckaget blir för stort, kan det leda till felmoder som i sin tur leder till dammbrott. Damminstrumentering som möjliggör övervakning av läckage i fyllningsdammar är ett krav enligt RIDAS. På nedströmssidan av fyllningsdammar finns det dränagerör som samlar upp och leder läckagevatten till platser där läckaget mäts med något slags instrument. Detta mätinstrument mäter inte endast läckaget genom fyllningsdammar, utan påverkas även av yttre faktorer såsom nederbörd och evapotranspiration. Detta examensarbete syftar därför att utveckla en generell metod för läckageövervakning vid fyllningsdammar, för att erhålla det normala läckaget. Hur det normala läckaget kan erhållas allmängiltigt för fyllningsdammar har presenterats. Det normala läckaget genom dammkroppen kan antingen erhållas med hjälp av fysikalisk läckageberäkning (qD1,Fysikalisk) eller från läckagemätning (qD1,Läckagemätning). Fysikalisk läckageberäkning bygger på en genomströmningsmodell baserat på fysikaliska samband. Läckage från läckagemätning baseras på en vattenbalansekvation där läckageflödet är en term av flera, som uppmätt läckage nedströms dammen, nederbörd och avdunstning. En fallstudie har genomförts för en av Vattenfalls dammanläggningar för att testa den metodik som framtagits för erhållande av det normala läckaget. De fysikaliska läckageberäkningarna har modellerats fram med hjälp av COMSOL Multiphysics och läckaget från läckagemätningarna har beräknats fram med hjälp av vattenbalansekvationen och indata på hydrologi. Resultatet visar att det är viktigt att ta hänsyn till de yttre faktorerna från vattenbalansekvationen eftersom dessa kan ha en betydande påverkan på det läckageflöde som faktiskt mäts. Vidare bedöms det betydande att modellera läckage baserat på en fysikalisk baserad strömningsmodell eftersom detta värde sällan finns idag. Då kan en jämförelse av läckage från läckagemätningar jämföras med det fysikaliska läckaget. Det bedöms att beräkning av läckage från läckagemätningar med hjälp av vattenbalansekvationen är en bra metod för att beräkna läckaget genom dammar. Dock behöver den studerade dammanläggningen en djupare analys för att senare kunna tillsätta gränsvärden. Detta genom att även undersöka läckage under dammkroppen och magasinsförändringar vid beräkning av läckage från läckagemätningar. Det fysikaliska läckaget genom att modellera genomströmningen för hela geometrin och genom att utföra en tidsberoende modellering. / Embankment dams are not completely impervious as its core materials has a certain permeability. This seepage is important to monitor to follow-up to ascertain that it stays as expected. If the seepage increase above design, failure modes could occur and ultimately a dam failure. The Swedish dam safety guideline RIDAS deals with this safety aspect by requirements on instrumentation to measure seepage. Downstream embankment dams, drainage leads seepage water to an outflow point where seepage can be measured. However, at these points the measured flow also is impacted by external factors such as precipitation and evapotranspiration. The aim of this report is to propose a method where the measured flow by post-processing can exclude the impact of these external factors. The normal seepage through a dam can either be obtained by modelling (where the physical seepage has been obtained based on physical relationships) or by a water balance equation (where the seepage from measurement downstream a dam is a part of the water balance equation, including the impact by precipitation and evapotranspiration. A case study has been carried out on a dam operated by Vattenfall, as a means to assess the proposed methodology. The seepage has been modelled using the COMSOL Multiphysics software, and the seepage from measurements has been calculated by the water balance equation. The results show that it is important to take into account external factors as it clearly affects the measured seepage flow. Furthermore, it is of great importance to calculate the theoretical design seepage, which is a threshold value level that is rarely modelled today. If both the seepage from measurements and theoretical seepage is obtained, a comparison of these can be made. The seepage from measurements (with the help of the water balance equation) is a good method to obtain embankment dam seepages. However, the results from the case study implies that further work is needed to be able to set relevant limit values.