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Hidroquímica e aspectos diagenéticos dos sistema aqüífero Bauru na região sudoeste do estado de São PauloStradioto, Marcia Regina [UNESP] 12 July 2007 (has links) (PDF)
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stradioto_mr_me_rcla.pdf: 2953628 bytes, checksum: 6040f85bad204d9e807f0b3ddd58c5bd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho tem como objetivos estudos petrológicos e hidroquímicos em área de ocorrência dos sedimentos do Grupo Bauru, na região sudoeste paulista. A análise petrográfica e a evolução diagenética foram realizadas com a utilização de microscopia óptica, microscopia eletrônica de varredura e difratometria de Raios X. Para caracterização hidroquímica foram realizadas análises físico-químicas. A análise hidroquímica apontou o predomínio das águas bicarbonatadas cálcicas e sódicas e, secundariamente aparecem as clorosulfatadas cálcicas e as cloretadas sódicas. As águas bicarbonatadas sódicas concentram-se na porção leste, nordeste e central da área, enquanto as bicarbonatadas cálcicas distribuem-se por toda a área, com discreto predomínio na porção central. Quanto à composição detrítica, os arenitos do Grupo Bauru são constituídos essencialmente por quartzo e feldspatos e em menor quantidades aparecem os fragmentos líticos e os minerais acessórios. Os principais processos diagenéticos identificados nos arenitos analisados foram dissoluções de minerais pesados, fragmentos líticos e aluminossilicatos; cimentação por calcita microcristalina, formação de argilominerais, cimentação por calcita em mosaico e tardia e cimentação por zeólitas. / The present research has as objective petrologic and hydrochemical studies in area of occurrence of the sediments of the Bauru Group, in the São Paulo southwestern region. Optical microscopy, scanning electron microscopy and X-ray diffraction were applied in the petrographic analysis and the diagenetic evolution. To the hydrochemical characterization was used physical-chemical analyses. The hydrochemical analysis revealed the predominance of bicarbonated calcic and sodic waters and secundarily appear chlorosulphated calcic and the sodic chlorinated. The bicarbonated sodic waters concentrate in the east, northeast and central portion of the area, while the bicarbonated calcic are distribute for all the area, with discrete predominance in the central portion. How much to the detritic composition, the sandstone of Bauru Group are constituted essentially by quartz and feldspars and in minor amounts appear the lytic fragments and the accessory minerals. The main diagenetic processes identified in the sandstone analyzed had been heavy mineral, lytic fragments and aluminossilicate dissolutions, cementation by microcrystalline calcite, formation by clay minerais, cimentation by recrystallized calcite and cimentation by zeolite.
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Hidroquímica e aspectos diagenéticos dos sistema aqüífero Bauru na região sudoeste do estado de São Paulo /Stradioto, Marcia Regina. January 2007 (has links)
Orientador: Chang Hung Kiang / Banca: Alexandre Campane Vidal / Banca: Osmar Sinelli / Resumo: O presente trabalho tem como objetivos estudos petrológicos e hidroquímicos em área de ocorrência dos sedimentos do Grupo Bauru, na região sudoeste paulista. A análise petrográfica e a evolução diagenética foram realizadas com a utilização de microscopia óptica, microscopia eletrônica de varredura e difratometria de Raios X. Para caracterização hidroquímica foram realizadas análises físico-químicas. A análise hidroquímica apontou o predomínio das águas bicarbonatadas cálcicas e sódicas e, secundariamente aparecem as clorosulfatadas cálcicas e as cloretadas sódicas. As águas bicarbonatadas sódicas concentram-se na porção leste, nordeste e central da área, enquanto as bicarbonatadas cálcicas distribuem-se por toda a área, com discreto predomínio na porção central. Quanto à composição detrítica, os arenitos do Grupo Bauru são constituídos essencialmente por quartzo e feldspatos e em menor quantidades aparecem os fragmentos líticos e os minerais acessórios. Os principais processos diagenéticos identificados nos arenitos analisados foram dissoluções de minerais pesados, fragmentos líticos e aluminossilicatos; cimentação por calcita microcristalina, formação de argilominerais, cimentação por calcita em mosaico e tardia e cimentação por zeólitas. / Abstract: The present research has as objective petrologic and hydrochemical studies in area of occurrence of the sediments of the Bauru Group, in the São Paulo southwestern region. Optical microscopy, scanning electron microscopy and X-ray diffraction were applied in the petrographic analysis and the diagenetic evolution. To the hydrochemical characterization was used physical-chemical analyses. The hydrochemical analysis revealed the predominance of bicarbonated calcic and sodic waters and secundarily appear chlorosulphated calcic and the sodic chlorinated. The bicarbonated sodic waters concentrate in the east, northeast and central portion of the area, while the bicarbonated calcic are distribute for all the area, with discrete predominance in the central portion. How much to the detritic composition, the sandstone of Bauru Group are constituted essentially by quartz and feldspars and in minor amounts appear the lytic fragments and the accessory minerals. The main diagenetic processes identified in the sandstone analyzed had been heavy mineral, lytic fragments and aluminossilicate dissolutions, cementation by microcrystalline calcite, formation by clay minerais, cimentation by recrystallized calcite and cimentation by zeolite. / Mestre
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Hydrochemistry of natural waters from the river Darent catchment, KentSmith, A. C. S. January 1975 (has links)
No description available.
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Modelling Chlorine Transport in Temperate SoilsIbikunle, Olatunde Idris January 2007 (has links)
<p>Microbes have been suggested to have a strong impact on the transportation of chlorine in soils. There are speculations about environmental factors limiting microbial effect on chlorine movement and retention. For this study, a numerical hydrochemical model was built to describe microbial transformation of chlorine in a laboratory lysimeter experiment. Undisturbed soil cores used to set-up the experiment were collected from a coniferous forest soil in southeast Sweden. The lysimeters were modelled in groups depending on their different water and chloride treatments. Microbial transformation of chlorine was better described under high water residence times and high chloride loads compared to low water residence times and low chloride loads. Microbial activity was also shown to properly account for a sudden shift from net-chlorine retention to net chlorine release in most of the lysimeters. Oxygen proved to be very important in accounting for the short-term shift from chloride retention to release in all the lysimeters. Model outcome revealed that 0.02– 0.10 mg Cl- could be available per day in a coniferous soil depending on season and other soil conditions. This study shows that modeling enable a better understanding of chlorine biogeochemistry. It also confirms the speculated importance of microbial activities on chloride availability in soils.</p>
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Modelling Chlorine Transport in Temperate SoilsIbikunle, Olatunde Idris January 2007 (has links)
Microbes have been suggested to have a strong impact on the transportation of chlorine in soils. There are speculations about environmental factors limiting microbial effect on chlorine movement and retention. For this study, a numerical hydrochemical model was built to describe microbial transformation of chlorine in a laboratory lysimeter experiment. Undisturbed soil cores used to set-up the experiment were collected from a coniferous forest soil in southeast Sweden. The lysimeters were modelled in groups depending on their different water and chloride treatments. Microbial transformation of chlorine was better described under high water residence times and high chloride loads compared to low water residence times and low chloride loads. Microbial activity was also shown to properly account for a sudden shift from net-chlorine retention to net chlorine release in most of the lysimeters. Oxygen proved to be very important in accounting for the short-term shift from chloride retention to release in all the lysimeters. Model outcome revealed that 0.02– 0.10 mg Cl- could be available per day in a coniferous soil depending on season and other soil conditions. This study shows that modeling enable a better understanding of chlorine biogeochemistry. It also confirms the speculated importance of microbial activities on chloride availability in soils.
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Υδρογεωλογική μελέτη στην περιοχή του ΑιγίουΤριάντου, Γεωργία - Αντιγόνη 07 October 2011 (has links)
Στα πλαίσια της παρούσας διπλωματικής εργασίας συλλέχθηκαν τα μετεωρολογικά δεδομένα της ευρύτερης περιοχής του Αιγίου, διεξήχθησαν μηνιαίες μετρήσεις στάθμης ενώ κατά τον Οκτώβριο του 2008 έγινε δειγματοληψία νερού από πηγάδια της περιοχής, με στόχο να μελετηθούν οι υδρογεωλογικές και υδροχημικές συνθήκες που επικρατούν στην περιοχή και να καθοριστούν οι παράμετροι του υδρολογικού ισοζυγίου.
Η περιοχή μελέτης ανήκει στον νομό Αχαΐας και αποτελεί τμήμα της Κορινθιακής Τάφρου. Το υπόβαθρο της περιοχής δομείται από τους σχηματισμούς της ζώνης Ωλονού-Πίνδου που έχουν επιφανειακή εμφάνιση σε υψηλότερα υψόμετρα, ενώ το πεδινό τμήμα της περιοχής καλύπτεται Πλειο-Πλειστοκαινικούς και Τεταρτογενής σχηματισμούς.
Ο συντελεστής εξατμισοδιαπνοής για την περιοχή έρευνας έχει τιμή 0,77 και το πλεόνασμα νερού εμφανίζεται τους μήνες Ιανουάριο έως Μάρτιο, Νοέμβριο και Δεκέμβριο. Η μεγαλύτερη διακύμανση της στάθμης του υδροφόρου παρατηρείται στα 1,15 (m) και η υδραυλική κλίση που υπολογίστηκε κυμαίνεται από 4‰ ‐6‰. Τέλος τα υπόγεια νερά της περιοχής είναι δυνατόν να ομαδοποιηθούν σε δυο κύριους υδροχημικούς τύπους Ca‐HCO3 και Ca-Mg‐Na‐SO4‐HCO3. / In the frames of this study the climatological data of the broader area of Aigion were collected. Moreover, water level measurements and groundwater sampling has been carried out in order to define the hydrochemical and hydrogeological that prevail in the study area. The water balance of the area was also estimated.
The study area is located in Achaia prefecture and consists a part of the Corinth Trench. The bedrock of the study area consists of the formations of Olonos-Pindos zone that out crop in the mountainous part, whereas the Neogene and Quaternary formations cover the lowlands of the study area.
The evaporotranspiration coefficient is 0.77 and there is a surplus of water during the periods January-March and November-December. The highest variance of water level of the aquifer was 1.15 (m) and the hydraulic gradient ranges between 4‰ ‐6‰. Finally, the groundwater samples of the study area can be classified into two hydrochemical types Ca‐HCO3 και Ca-Mg‐Na‐SO4‐HCO3.
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Μελέτη των υδροχημικών παραμέτρων των καρστικών πηγών Λάμπρας - Αγίου ΔημητρίουΠαναγή, Γιώργος 06 December 2013 (has links)
Η πτυχιακή εργασία με τίτλο «Μελέτη των υδροχημικών παραμέτρων των καρστικών πηγών Λάμπρας – Αγ. Δημητρίου» έχει σκοπό τη μελέτη των υδρογεωλογικών συνθηκών και κυρίως των υδροχημικών διαδικασιών του καρστικού συστήματος των Τριαδικών Ανθρακικών Λατυποπαγών, το οποίο εκφορτίζεται στο μέτωπο των πηγών «Λάμπρας - Αγ. Δημητρίου» στην ευρύτερη περιοχή του νότιου Ξηρόμερου, ΝΔ Αιτωλοακαρνανία. Η πτυχιακή εργασία πραγματοποιήθηκε στα πλαίσια του ερευνητικού προγράμματος «Κ. Καραθοδωρή» με τίτλο «Διερεύνηση των μηχανισμών λειτουργίας και της τρωτότητας των καρστικών συστημάτων-Παράδειγμα εφαρμογής στο καρστικό σύστημα των κατώτερων γεωλογικών ενοτήτων της Ιονίου Ζώνης».
Το γεωλογικό υπόβαθρο της περιοχής μελέτης αποτελείται από Τριαδικούς εβαπορίτες. Λόγω του μικρότερου ειδικού βάρους τους, παρουσιάζουν φαινόμενα διαπειρισμού που σε συνδυασμό με το τεκτονικό περιβάλλον της ζώνης, συντελούν στον σχηματισμό και την ανάπτυξη των Τριαδικών Ανθρακικών Λατυποπαγών (ΤΑΛ). Γεωτεκτονικά η περιοχή ανήκει στην Ιόνια ζώνη. Η εβαποριτική σειρά αποτελείται από εμφανίσεις γύψου και ανυδρίτη, κυρίως κατά μήκος των μεγάλων ρηγμάτων και εφιππεύσεων. Οι σχηματισμοί της μετά-Τριαδικής ανθρακικής ακολουθίας που απαντώνται στην περιοχή αποτελούνται από τους Ιουρασικούς Ασβεστόλιθους «Παντοκράτορα», τους Ασβεστόλιθους Λιάσιου και τους Κρητιδικούς Ασβεστόλιθους του σχηματισμού της «Βίγλας». Εμφανίζονται επίσης μεταλπικοί σχηματισμοί, όπως Τεταρτογενείς και αλλουβιακές αποθέσεις.
Ο υπό μελέτη καρστικός υδροφόρος αναπτύσσεται στα Τριαδικά Ανθρακικά Λατυποπαγή και οριοθετείται προς το βορρά από την διαπιστωμένη με παλαιότερες γεωφυσικές μεθόδους αναθόλωση των εβαποριτών στην περιοχή Φυτείες και προς τη δύση από την επώθηση των Τριαδικών Ανθρακικών Λατυποπαγών στους Ιουρασικούς ασβεστόλιθους «Παντοκράτορα» των Ακαρνανικών Ορέων. Η περιοχή χαρακτηρίζεται από την έλλειψη υδρογραφικού δικτύου. Το μέσο ετήσιο ύψος βροχόπτωσης της περιοχής είναι 836 mm, που αντιστοιχεί σε μέσο ετήσιο όγκο νερού βροχής 121,33 x 106 m3.
Το καρστικό αυτό σύστημα εκφορτίζεται στην επαφή των Τριαδικών Ανθρακικών Λατυποπαγών με τις Τεταρτογενείς αποθέσεις του κάμπου του Λεσινίου, σχηματίζοντας το μέτωπο των πηγών «Λάμπρας – Αγ. Δημητρίου» και ένα δεύτερο, μικρότερο μέτωπο πηγών στο νοτιοδυτικό άκρο του καρστικού συστήματος. Το μέτωπο των πηγών «Λάμπρας – Αγ. Δημητρίου» έχει μήκος περίπου 3 km και μέση ετήσια παροχή περίπου 270 x 106 m3/yr. Για τη κατανόηση της λειτουργίας του καρστικού συστήματος πραγματοποιήθαν δειγματοληψίες στις κύριες πηγές δύο φορές κάθε μήνα, κατά τη διάρκεια του έτους 2011. Στη σθνέχιεα έγινε στατιστική επεξεργασία των χημικών αναλύσεων. Τα νερά των πηγών έχουν χημισμό Ca - SO4 - HCO3 ή Ca - HCO3 - SO4. Αυτοί είναι οι κυρίαρχοι υδροχημικοί τύποι των πηγών καθώς και των νερών της ευρύτερης περιοχής μελέτης, που ερμηνεύονται με την παρουσία των ασβεστολιθικών και εβαποριτικών πετρωμάτων, από την διάλυση των οποίων, τα νερά εμπλουτίζονται σε ιόντα ασβεστίου, σε θειικά και όξινα ανθρακικά ιόντα. / The hydrogeological, hydrochemical and environmental investigation of the karstic system of the Triassic Carbonate Breccia (TCB) which discharges through the spring front of ‘’Lambra’’-Αg. Dimitrios and lies in southern Ksiromero, SW Aitoloakarnania were made for the purpose prior thesis.
The study area is part of the Ionian Geotectonic Zone and its geological background consists of the Triassic Evaporites. The TCB where formed under the combination of the tectonic and orogenetic setting of the External Hellenides and the diapir phenomena of the Triassic Evaporites. The after-Triassic Carbonate series is also present in the study area, with limited expansion, which consists of the Jurassic Limestones known as ‘’Pantokratoras Limestones’’, the Lias Limestones, the Cretaceus Limestones of the ‘’Vigla’’ formation and the Eocene Limestones. Recent formations are also present: Quartenary sediments with marl and terra rossa variations, marls and alluvial sediments. The karstic aquifer develops through the TCB and its margins are defined by the diapir phenomena in the area of Fities in the North, the Mahalas thrust in the east and the overthrust of the TCB onto the Jurassic ‘Pantokratoras’’ Limestones in the West.
The karst system of the TCB discharges through numerous springs (>20) in the contact of the TCB with the quartenary deposits of the Lesini Fields. The spring front of Lambra is 3km long with mean annual discharge ~270*106m3/yr. A secondary discharge front is present in the West of the main front with alterations in the water chemism and larger ion concentrations. The hydrochemical type of the springs water is Ca-SO4-HCO3. The hydrochemical investigation provided two major and two minor hydrochemical types for the groundwater: The main types Ca-SO4-HCO3 and Ca- HCO3-SO4 and the secondary types Ca-SO4 and Ca-Na-SO4-HCO3. The elevated concentration of the sulfate anions is due to the dissolution of the Triassic Evaporites of the background.
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Avaliação da qualidade da água subterrânea no campus do Instituto de Pesquisas Energéticas e Nucleares - IPEN / Groundwater quality evaluation at the campus of the Institute of Energy and Nuclear Research - IPENSoares, Sabrina Moura Villa 16 March 2018 (has links)
O início das atividades para implantação e operacionalização do Sistema de Gestão Ambiental do IPEN teve inicio em meados de 2011/2012 com o processo de regularização ambiental do IPEN/CNEN, por intermédio de seu Termo de Compromisso de Ajustamento de Conduta TCAC (IBAMA/IPEN/CNEN) demostrando as intenções do IPEN/CNEN em adequar-se ambientalmente segundo as diretrizes do IBAMA, respaldado nos aspectos legais em vigor. Esta operacionalização do SGA vem complementar as ações de licenciamento nuclear, em atendimento aos requisitos legais da Resolução CNEN Nº 112/2011, que dispõe sobre o licenciamento de instalações radiativas que utilizam fontes seladas, fontes não seladas, equipamentos geradores de radiação ionizante e instalações radiativas para produção de radioisótopos. O desenvolvimento prático da política ambiental da instituição foi o resultado do conjunto das ações dos programas institucionais, entre eles o Programa de monitoração Químico Ambiental PMQA. As informações associadas a esse Programa visam prover o IPEN de documentação técnica necessária para atendimento às legislações ambientais vigentes e ao atendimento as solicitações do TAC IBAMA referente às suas instalações localizadas na Av. Professor Lineu Prestes, nº 2.242, Cidade Universitária, Butantã, São Paulo, Capital. O Programa Monitoração Ambiental dos Compostos Químicos Estáveis do Instituto de Pesquisas Energéticas e Nucleares IPEN - PMA-Q do IPEN, executado pelo Centro de Química e Meio Ambiente CQMA, desde 2006 estabelece os requisitos básicos para a proteção da vida e da propriedade nas suas dependências, onde são manuseados produtos químicos, biológicos e radioativos e equipamentos e, contempla avaliação da qualidade dos recursos hídricos subterrâneos assim como a caracterização do efluente líquido liberado na rede coletora de esgoto do instituto. Esse Programa contempla a caracterização bimestral da qualidade da água subterrânea em nove poços de monitoramento, avaliando compostos estáveis e radioativos. As análises dos compostos estáveis são realizadas no Laboratório de Análises Químicas e Ambientais LAQA do CQMA. Um sistema de monitoramento tem o papel de acusar a influência de uma determinada fonte de poluição na qualidade da água subterrânea. A localização estratégica e a utilização racional dos poços de monitoramento, aliadas a métodos eficientes de coleta, acondicionamento e análise de amostras, permitem resultados bastante precisos sobre a influência, na qualidade da água subterrânea. A composição natural e a verificação de indícios de poluição ou contaminação das águas podem ser avaliadas por meio de parâmetros físicos, químicos e microbiológicos. Esta avaliação é fundamental para determinação da adequabilidade das águas em função do uso requerido. Desta forma, a proposta do trabalho está alinhada ao Programa de Monitoramento Ambiental dos Compostos Químicos Estáveis do Instituto de Pesquisas Energéticas e Nucleares IPEN, propondo uma caracterização hidroquímica das águas subterrâneas com o objetivo de conhecer as principais características qualitativas desse recurso. Esse conhecimento é fundamental para subsidiar as ações de controle da poluição ambiental. Com os resultados da rede de monitoramento de qualidade, obtidos nos poços tubulares, possibilitarão o estabelecimento de Valores de Referência de Qualidade VRQs para os poços de monitoramento do IPEN. / The beginning of the activities for the implementation and operationalization of the Environmental Management System of IPEN began in 2011/2012 with the environmental regularization process of IPEN / CNEN, through its Term of Commitment of Adjustment of Conduct - TCAC (IBAMA / IPEN / CNEN), demonstrating the intentions of IPEN / CNEN to comply with the environment according to the IBAMA guidelines, supported by the legal aspects in force. This operation of the EMS complements the nuclear licensing actions, in compliance with the legal requirements of Resolution CNEN Nº. 112/2011, which deals with the licensing of radiative installations using sealed sources, unsealed sources, ionizing radiation generating equipment and radiative installations for the production of radioisotopes. The practical development of the institution\'s environmental policy was the result of all the actions of the institutional programs, among them the Environmental Chemistry Monitoring Program (PMQA). The information associated with this Program is intended to provide IPEN with the technical documentation required to comply with current environmental legislation and to comply with requests from the IBAMA TAC for its facilities located at Av. Professor Lineu Prestes, nº 2.242, Cidade Universitária, Butantã, São Paulo, Capital. The Environmental Monitoring Program for Stable Chemical Compounds of the IPEN-PMA-Q Institute, run by the Chemistry and Environment Center (CQMA) since 2006 establishes the basic requirements for the protection of life and property in its dependencies, where chemical, biological and radioactive products and equipment are handled, and includes the evaluation of the quality of groundwater resources as well as the characterization of the liquid effluent released in the sewage collection network of the institute. This Program contemplates the bimonthly characterization of groundwater quality in nine monitoring wells, evaluating stable and radioactive compounds. Analyzes of the stable compounds are carried out at the Laboratory of Chemical and Environmental Analysis - LAQA of the CQMA. A monitoring system has the role of accusing the influence of a given source of pollution on the quality of groundwater. The strategic location and the rational use of the monitoring wells, together with efficient methods of collection, conditioning and analysis of samples, allow very precise results on the influence, in the groundwater quality. The natural composition and the verification of signs of contamination or contamination of the waters can be evaluated through physical, chemical and Microbiological parameters. This evaluation is fundamental to determine the suitability of the water in function of the required use. In this way, the proposal of the work is aligned with the Environmental Monitoring Program of Stable Chemical Compounds of the Institute of Energy and Nuclear Research - IPEN, proposing a hydrochemical characterization of groundwater with the purpose of knowing the main qualitative characteristics of this resource. This knowledge is fundamental to subsidize actions to control environmental pollution. The results of the quality monitoring network, obtained from tubular wells, will enable the establishment of Quality Reference Values VRQs for IPEN monitoring wells.
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Salinity of irrigation water in the Philippi farming area of the cape flats, Cape Town, South AfricaAza-Gnandji Cocou Davis Ruben January 2011 (has links)
<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>
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Salinity of irrigation water in the Philippi farming area of the cape flats, Cape Town, South AfricaAza-Gnandji Cocou Davis Ruben January 2011 (has links)
<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>
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