La compréhension du cycle de l'eau d'une région où les ressources en eau sont limitées est fondamentale pour assurer une gestion durable de celles-ci, c'est le cas de Galápagos. Cette thèse présente la première étude intégrée du fonctionnement hydrogéologique des aquifères perché de l'île San Cristóbal. Pour ce faire, une approche pluridisciplinaire, fondée sur la mise en place d'un site expérimental sur le bassin versant de Cerro Gato (CG), a été conduite. Pour quantifier les entrées d'eau dans le système hydrologique une approche canopée-transfert hydrique du sol a été utilise. La recharge est principalement affectée par l'altitude en raison de l'effet orographique sur les gradients de pluie et d'évapotranspiration. Néanmoins, à haute altitude, la différence est principalement associée à la couverture végétale en raison de l'apport additionnel fourni par l'interception du brouillard sous la forêt. Une analyse hydrologique montre que les pertes des bassins versants situés à haute-altitude deviennent les entrées d'eau souterraine des bassins versants situés à moyenne altitude (comme CG). Les données du méthode électromagnétique héliportée SkyTEM permettent définir l'extension du bassin hydrogéologique de CG qui est plus grande que le bassin hydrologique. Des approches précédemment décrites, découlent un modèle conceptuel des sources de CG. Ainsi, les eaux souterraines de ces sources sont issues d'un aquifère perché qui s'est formé à la faveur d'une fine couche peu perméable. Ce modèle est testé par simulations numériques qui montrent cette plausibilité. Cette thèse fournit les fondements scientifiques d'une gestion durable des ressources en eau. / The understanding of the hydrogeological functioning in regions such as San Cristobal Island (Galapagos), where water is limited, is fundamental for a suitable management of its resources. This work is the first study of this type on high-level aquifers in San Cristobal using a multi-disciplinary approach, based in the implementation of an experimental site and modeling strategies. For this purpose, a hydrological network was installed in Cerro Gato (CG) and surrounding watersheds. Inputs to the watershed are estimated using the joint modeling of a canopy and soil water transfer. Recharge rates are mainly affected by altitude in mid-elevation watersheds, whereas land cover is the main controlling factor at high-elevation watersheds because of the additional input of fog interception in forests. A hydrological analysis shows that losses from the high-elevation basins become groundwater inputs in the mid-elevation basins, while others have inputs from watersheds at the same altitude, such as CG. The detailed geometry of its hydrogeological watershed is obtained from the dataset of a high resolution AEM SkyTEM survey, which confirms the assumption that its hydrogeological watershed is bigger than its hydrological one. Results from these approaches allow proposing a hydrogeological conceptual model for the springs of CG, where the groundwater flow of springs is fed by a perched aquifer suspended by a low permeability thin layer. This model is tested with numerical simulations, which confirm the plausibility of the existence of a perched aquifer. This thesis provides scientific basis for an effective water management strategy.

Submitted by Leticia Schettini (leticia@ufrrj.br) on 2016-10-06T11:35:04Z No. of bitstreams: 1 2007 - Rafael Silva Barboza.pdf: 2062893 bytes, checksum: c7d9166e3fe66028a7acdadb02fed002 (MD5) / Made available in DSpace on 2016-10-06T11:35:04Z (GMT). No. of bitstreams: 1 2007 - Rafael Silva Barboza.pdf: 2062893 bytes, checksum: c7d9166e3fe66028a7acdadb02fed002 (MD5) Previous issue date: 2007-06-27 / Instituto Terra de Prote??o Ambiental, ITPA, Brasil. / The air basin is a three-dimensional space that conduct and distribute the winds over the drainage basin. In Rio de Janeiro?s state, 48% of the territory is constituted by Atlantic slope, where were registered 16 air basins with specific environmental features, distributed in 20% of the area. Based on the conformation of morphometrics parameters the air basins were grouped, by Multivariate Analysis - Cluster, with Euclidean distance of 48%, significance level of 95% and correlation coefficient of 0.7132, in 5 groups with similar forms. To evaluate the hydrologic effects within the air basins, it was used as a study case, the air basin of Angra dos Reis, where the magnitude of the interception of clouds was measured in the escape zone from the topographic divide of the Pirai river basin (leeward), in different distance away, with and without natural barriers, during the winter and summer. It was used vertical intercept sampling area equivalent to 0.45% of the forests in the region. The variation of the removal of the topographic divide occurred until 500 m of altitude, this limit may be the end of the escape zone and the beginning of the air basin distribution zone. The effect of air basin represented additional of 44% of the volume of rain in topographic divide (point 1), 39% at 4.5 km (point 2) and 42% at 7.5 km (point 3) of the point 1, in concordant direction of the flow. The effect of the orography in the trajectory of the winds, varied in an irregular way in winter and in summer, maintaining differential of 23% and 77% in point A (obstruction of 85% of the cross section) and 32% and 68% in point B (obstruction of 80% of the cross section). In areas under the influence of air basins, the variables and environmental processes can be crucial to offer environmental services in drainage basins. / A Bacia A?rea ? um espa?o tridimensional que conduz e distribui os ventos sobre as bacias hidrogr?ficas. No Estado do Rio de Janeiro, 48% do territ?rio ? composto pela vertente Atl?ntica, onde foram registradas 16 bacias a?reas com caracter?sticas ambientais espec?ficas, distribu?das em 20% da ?rea. Baseado na conforma??o de par?metros morfom?tricos as bacias a?reas foram agrupadas, atrav?s de An?lise Multivariada ? Cluster, com dist?ncia Euclidiana de 48%, n?vel de signific?ncia de 95% e coeficiente de correla??o de 0,7132 em 5 grupos com formas similares. Para avaliar os efeitos hidrol?gicos dentro das bacias a?reas, utilizou-se como estudo de caso a bacia a?rea de Angra dos Reis, onde a magnitude da vari?vel intercepta??o das nuvens foi medida na zona de escape, a partir do interfl?vio da bacia hidrogr?fica do rio Pirai (sotavento), em dist?ncias de afastamento distintas, com e sem barreiras orogr?ficas, durante o inverno e ver?o. Utilizou-se ?rea amostral de intercepta??o vertical equivalente a 0,45% das florestas da regi?o. A varia??o do afastamento do interfl?vio ocorreu at? desn?vel de 500 m em altitude, podendo ser este limite o fim da zona de escape e in?cio da zona de distribui??o da bacia a?rea. O efeito da bacia a?rea representou adicional de 44% em volume de chuva no interfl?vio (ponto 1), 39% a 4,5 km (ponto 2) e 42% a 7,5 km (ponto 3) do ponto 1 em dire??o concordante ao sentido do fluxo. O efeito da orografia no corredor variou de forma irregular no inverno e no ver?o, mantendo diferencial de 23% e 77% no ponto A (obstru??o de 85% da se??o transversal) e 32% e 68% , no ponto B (obstru??o de 80% da se??o transversal). Em ?reas sob influ?ncia de bacias a?reas, as vari?veis e processos ambientais podem ser determinantes para ofertar servi?os ambientais nas bacias hidrogr?ficas.

Submitted by Leticia Schettini (leticia@ufrrj.br) on 2016-10-06T11:57:21Z No. of bitstreams: 1 2007 - Rafael Silva Barboza.pdf: 2062893 bytes, checksum: c7d9166e3fe66028a7acdadb02fed002 (MD5) / Made available in DSpace on 2016-10-06T11:57:21Z (GMT). No. of bitstreams: 1 2007 - Rafael Silva Barboza.pdf: 2062893 bytes, checksum: c7d9166e3fe66028a7acdadb02fed002 (MD5) Previous issue date: 2007-06-27 / Instituto Terra de Prote??o Ambiental, ITPA, Brasil. / The air basin is a three-dimensional space that conduct and distribute the winds over the drainage basin. In Rio de Janeiro?s state, 48% of the territory is constituted by Atlantic slope, where were registered 16 air basins with specific environmental features, distributed in 20% of the area. Based on the conformation of morphometrics parameters the air basins were grouped, by Multivariate Analysis - Cluster, with Euclidean distance of 48%, significance level of 95% and correlation coefficient of 0.7132, in 5 groups with similar forms. To evaluate the hydrologic effects within the air basins, it was used as a study case, the air basin of Angra dos Reis, where the magnitude of the interception of clouds was measured in the escape zone from the topographic divide of the Pirai river basin (leeward), in different distance away, with and without natural barriers, during the winter and summer. It was used vertical intercept sampling area equivalent to 0.45% of the forests in the region. The variation of the removal of the topographic divide occurred until 500 m of altitude, this limit may be the end of the escape zone and the beginning of the air basin distribution zone. The effect of air basin represented additional of 44% of the volume of rain in topographic divide (point 1), 39% at 4.5 km (point 2) and 42% at 7.5 km (point 3) of the point 1, in concordant direction of the flow. The effect of the orography in the trajectory of the winds, varied in an irregular way in winter and in summer, maintaining differential of 23% and 77% in point A (obstruction of 85% of the cross section) and 32% and 68% in point B (obstruction of 80% of the cross section). In areas under the influence of air basins, the variables and environmental processes can be crucial to offer environmental services in drainage basins. / A Bacia A?rea ? um espa?o tridimensional que conduz e distribui os ventos sobre as bacias hidrogr?ficas. No Estado do Rio de Janeiro, 48% do territ?rio ? composto pela vertente Atl?ntica, onde foram registradas 16 bacias a?reas com caracter?sticas ambientais espec?ficas, distribu?das em 20% da ?rea. Baseado na conforma??o de par?metros morfom?tricos as bacias a?reas foram agrupadas, atrav?s de An?lise Multivariada ? Cluster, com dist?ncia Euclidiana de 48%, n?vel de signific?ncia de 95% e coeficiente de correla??o de 0,7132 em 5 grupos com formas similares. Para avaliar os efeitos hidrol?gicos dentro das bacias a?reas, utilizou-se como estudo de caso a bacia a?rea de Angra dos Reis, onde a magnitude da vari?vel intercepta??o das nuvens foi medida na zona de escape, a partir do interfl?vio da bacia hidrogr?fica do rio Pirai (sotavento), em dist?ncias de afastamento distintas, com e sem barreiras orogr?ficas, durante o inverno e ver?o. Utilizou-se ?rea amostral de intercepta??o vertical equivalente a 0,45% das florestas da regi?o. A varia??o do afastamento do interfl?vio ocorreu at? desn?vel de 500 m em altitude, podendo ser este limite o fim da zona de escape e in?cio da zona de distribui??o da bacia a?rea. O efeito da bacia a?rea representou adicional de 44% em volume de chuva no interfl?vio (ponto 1), 39% a 4,5 km (ponto 2) e 42% a 7,5 km (ponto 3) do ponto 1 em dire??o concordante ao sentido do fluxo. O efeito da orografia no corredor variou de forma irregular no inverno e no ver?o, mantendo diferencial de 23% e 77% no ponto A (obstru??o de 85% da se??o transversal) e 32% e 68% , no ponto B (obstru??o de 80% da se??o transversal). Em ?reas sob influ?ncia de bacias a?reas, as vari?veis e processos ambientais podem ser determinantes para ofertar servi?os ambientais nas bacias hidrogr?ficas.

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