Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The SU Department of Forestry has the responsibility to monitor, assess and suggest management processes for water resources in some remote areas. The researchers need information on wind speed, wind direction, soil run-o , absorption and soil drainage. Most of the areas they are targeting have no form of GSM/GPRS coverage. This thesis presents the design and development of a Zigbee based wireless sensor network to send data from distributed sensor nodes to a ground station, all in a remote area. The ground station in turn uses a global commercial satellite communications system to send the eld data to a centralised host computer. This was accomplished through the integration of the most common and popular open source and commercial electronics prototyping platforms, namely, Arduino, Digi XBee radio, Raspberry Pi and Iridium modem. The system relies on an Arduino Uno working as a sensor node, Digi XBee radios for forming wireless mesh and multi-hop networks, Raspberry Pi being the heart of the ground station and the Iridium modem to send data to the master station through the Iridium gateway. A comprehensive literature study was conducted and a prototype of the system implemented. Various tests were conducted to determine and prove the feasibility of the system. / AFRIKAANSE OPSOMMING: Die Departement van Bosbou het die verantwoordelikheid om water hulpbronne in afgele e areas te monitor, evalueer en voorstelle te maak tov. die bestuur daarvan. Die navorsers benodig inligting oor windspoed, windrigting, grondwater a oop, -opname en -dreinering. Die meeste van die gebiede ter sprake het geen vorm van GSM / GPRS-dekking nie. Hierdie tesis beskryf die ontwerp en ontwikkeling van 'n Zigbee gebaseerde radio sensornetwerk om data vanaf verspreide sensornodes te stuur na 'n grondstasie. Die grondstasie op sy beurt maak gebruik van 'n globale kommersiele satelliet-kommunikasiestelsel om data van 'n afgele e plek in die veld te stuur na 'n gesentraliseerde rekenaarstelsel. Dit is gedoen deur van die mees algemene en gewilde prototipe oopbron en kommersiele platforms, naamlik Arduino, Digi XBee radio, Raspberry Pi en Iridium modem te integreer. Die sensornodes is gebaseer op 'n Arduino Uno, met Digi XBee radio's vir die radio- multihop netwerk. Die grondstasie is gebou om die Raspberry Pi en stuur data aan na die meesterstasie, via die Iridium modem en satellietstelsel. Na 'n omvattende literatuurstudie, is 'n prototipe van die stelsel ontwerp en geimplementeer. Omvattende toetse is gedoen om die korrekte werking en bruikbaarheid van die stelsel te bewys.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The contamination of surface water bodies due to antropic action has made water ever more scarce. Knowledge of the water quality is essential to determine instruments for it's management . Monitoring water quality in huge areas requires a high number of saimples for water quality control. This fact, allied to the high costs of water analysis, limits the evaluation that can be made of continental waters. Even though in later years geoprocessing and remote sensing techniques have been developed with important results in water quality studies, these techniques have yet to be applied in the study of aquatic systems in semiarid regions. Therefore, it was attempted to develop a methodology based on the spectral characteristics of water as a support method for the evaluation of water quality in semiarid regions. Water samples were collected in seven points from 2008 to 2010 (every two months) and in 20 points from 2011 and 2012 (every three months) . The campaigns for radiometric data acquisition occurred in 2011 and 2012, alongside the water sampling. The determinant factors and water similarity were identified by the multivariable analysis. Data from orbital and insitu remote sensing correlated with limnologic data were used. The determinant indicators for water quality in the Oros were defined mainly by the following factors: the geologic components of the soil; sediment transport by surface flow and organic pollution. The Cluster Analysis formed three distinct groups. The water similarity was defined by natural conditions and by the land use around the reservoir and along the basin. The models developed for limnologic variables, suspended inorganic solids, turbidity, transparency and electric conductivity, showed themselves to be trustworthy, indicating that these variables can be quantified remotely through remote sensing data. The models developed for the clorophile - a fitted well, indicating that this variable can be quantified accurately through in situand orbital remote sensing data. The general three banded model presented a better efficiency to that of the two band model. According to the developed model and the image use of the MERIS sensor, the Oros waters, as far as trophic state is concerned, presented 61.15% of it's water bater classified as eutrophic for the month of February, 2010. For the MERIS image of August 2011, 95.77% of it's waters were classified as eutrophic. Therefore, through remote sensing data it is possible to elaborate a water resources management at a lower cost, generating a usefull information for decision making by managers, vital for the implementation of public policies at county, regional, state and federal levels. / Com a contaminaÃÃo de corpos hÃdricos pela aÃÃo antrÃpica, a disponibilidade de Ãgua torna-se cada vez menor. O conhecimento da qualidade das Ãguas à essencial à proposiÃÃo de instrumentos de gestÃo das mesmas. O monitoramento em Ãreas extensas requer um elevado nÃmero de amostras para o controle da qualidade da Ãgua; este fato, aliado aos altos custos das anÃlises, limita a avaliaÃÃo do processo de degradaÃÃo das Ãguas interiores. Apesar do desenvolvimento, nos Ãltimos anos, das tÃcnicas de geoprocessamento e sensoriamento remoto, com a obtenÃÃo de informaÃÃes relevantes em estudo de qualidade de Ãguas, elas nÃo tÃm sido exploradas em estudos de sistemas aquÃticos de regiÃes semiÃridas. Com isso, objetivou-se desenvolver uma metodologia baseada nas propriedades espectrais da Ãgua como suporte a avaliaÃÃo de sua qualidade em ambientes semiÃridos. As amostras de Ãgua foram coletadas em sete pontos de 2008 a 2010 (bimestralmente) e em 20 pontos de 2011 a 2012 (trimestralmente). As campanhas para aquisiÃÃo de dados radiomÃtricos ocorreram em 2011 e 2012, concomitantes Ãs coletas das amostras de Ãgua. Os fatores determinantes e a similaridade das Ãguas foram identificados pelo emprego da anÃlise multivariada. Foram usados dados de sensoriamento remoto orbital e in situ, correlacionando com os dados limnolÃgicos. Os indicadores determinantes da qualidade das Ãguas do OrÃs sÃo definidos principalmente pelos seguintes fatores: processo natural de intemperismo dos componentes geolÃgicos do solo; carreamentos dos sÃlidos suspensos atravÃs do escoamento superficial das Ãguas e poluiÃÃo orgÃnica. A anÃlise de agrupamento formou trÃs grupos distintos. A similaridade das Ãguas foi definida pelas condiÃÃes naturais e pelas atividades antrÃpicas exercidas nas proximidades do reservatÃrio e ao longo da bacia. Os modelos desenvolvidos para as variÃveis limnolÃgicas, sÃlidos inorgÃnicos suspensos, turbidez, transparÃncia e condutividade elÃtrica, mostraram-se confiÃveis, indicando que essas variÃveis podem ser quantificadas remotamente a partir dos dados de sensoriamento remoto de campo. Os modelos desenvolvidos para a variÃvel clorofila-a sÃo confiÃveis, indicando que esta variÃvel pode ser quantificada remotamente a partir dos dados de sensoriamento remoto de campo e orbital com elevado grau de confiabilidade. O modelo geral de trÃs bandas apresentou desempenho superior ao modelo de duas bandas. De acordo com o modelo desenvolvido e com uso de imagens do sensor MERIS, as Ãguas do reservatÃrio OrÃs, quanto ao estado trÃfico, apresentaram 61,15% da sua bacia hidrÃulica classificadas como eutrÃfica, para o mÃs de fevereiro de 2010. Para a imagem MERIS de agosto de 2011, 95,77% das Ãguas foram classificadas como eutrÃficas. Portanto, com o uso do sensoriamento remoto à possÃvel elaborar um gerenciamento dos recursos hÃdricos de menor custo, gerando informaÃÃes Ãteis à tomada de decisÃes pelos gestores, vital para a implantaÃÃo de polÃticas pÃblicas em Ãmbito municipal, regional, estadual e federal.