Thesis (Ph. D.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 165-177). Also available on the World Wide Web.

Rainfall interception is a primary control over the moisture input to a forested ecosystem through the partitioning of precipitation into throughfall, stemflow, and an evaporated component (i.e. the interception loss). Rainfall interception is a spatially and temporally varying process at multiple scales, but heterogeneity in interception processes are poorly understood and poorly described in the literature. We need to know how net precipitation varies in ecosystems because natural systems are driven by non-linear ecohydrological processes where mean values cannot capture localized effects or the cumulative consequences associated with an extremely heterogeneous input. In this thesis, we present two studies that investigate the heterogeneity of interception loss and throughfall in a forested catchment in the western Cascades range of Oregon. In one study, we examined the spatio-temporal patterns among point measurements of throughfall depth and isotopic composition to determine the cause of isotopic differences between throughfall and rainfall. Our results indicated that the residual moisture retained on the canopy from previous events plays a major role in determining the isotopic composition of the next event's throughfall. Differences between the isotopic composition of throughfall samples could indicate further partitioning of throughfall into various flow-paths from the canopy. The second project examined the question of how vegetation variability and terrain complexity drive interception loss heterogeneity at the whole-catchment scale. We applied a simple interception model to a watershed gridded at a 50 m resolution to investigate the relative importance of topographic and vegetative controls over the spatial variability of interception loss. We found that storm characteristics are crucial regarding the impact of spatial heterogeneities in vegetation and evaporation rates. In the Pacific Northwest climate, interception loss is not highly variable for the majority of the year because the annual precipitation is dominated by large storms with low interception losses. However, the net precipitation input to a watershed becomes extremely heterogeneous in the summer due to high interception loss variability. Summer interception loss could be an important control over the spatial variability of the availability of moisture, coinciding with when vegetation is most water-limited. / Graduation date: 2013

A physically-based, user friendly, hydrologic computer simulation model was developed for pinyon-juniper woodland watersheds. The data requirements are minimum, requiring vegetation conditions, basic soil survey information, and daily values for precipitation and temperature. The model predicts runoff from cleared and uncleared watersheds by simulating hydrologic processes on a daily basis. The model was tested with data from small pinyon-juniper watersheds in central Arizona. A crack-forming vertisol was the dominant soil type, and a special feature for addressing its effects on runoff was included. No significant difference between predicted and observed annual runoff was found at the ninety-five percent confidence level.

Mais da metade da vegetação nativa no Brasil ocorrem em propriedades privadas, por isso a importância da compatibilização das atividades agropecuárias com a conservação dos recursos naturais. Os benefícios gerados pelos ecossistemas para os seres humanos são definidos como serviços ecossistêmicos, que podem ser pagos para incentivar a manutenção e restauração da vegetação nativa nas propriedades rurais, com os chamados programas de Pagamento por Serviços Ambientais (PSA). A metodologia proposta neste estudo proporciona um avanço no sentido do planejamento espacial da paisagem em propriedades privadas, a fim de aumentar o fornecimento de serviços ecossistêmicos, levando em conta a percepção dos tomadores de decisão no manejo do uso do solo, por meio de Análise de Decisão Multicritérios (MCDA). A metodologia foi testada na microbacia do córrego Cavalheiro, que é afetada pela fragmentação do habitat e conversão de terras para fins agrícolas. Os resultados mostraram que para os serviços ecossistêmicos hidrológicos, utilizados pelos programas de PSA brasileiros, deve existir uma ponderação entre a regulação do regime hidrológico com a consequente diminuição da vazão anual esperada devido ao incremento da área florestada. Em um dos cenários de uso e ocupação do solo, no qual se propôs a ocupação de 51,8 % da microbacia por vegetação nativa, houve uma diminuição de 81,25 % no escoamento superficial e de 32,2 % no escoamento de base. Entretanto, este aumento da cobertura vegetal provou ter a função de regulação hídrica, aumentando de 68 % para 87 % a contribuição da vazão de base no escoamento total da microbacia. Isso mostra que a decisão quanto ao tamanho das áreas de vegetação nativa deve ficar por conta das funções ecológicas mais exigentes, que para o caso da área de estudo mostrou ser o suporte à biodiversidade. O uso da ponderação dos critérios para a análise de decisão multicritério (MCDA) mostrou que os tomadores de decisão da microbacia estão interessados em novas formas de manejo de uso do solo, visando a regulação do regime hidrológico, aumento do suporte à biodiversidade e paisagens que tragam maior potencial às atividades de ecoturismo. Assim, os cenários com maiores áreas de vegetação nativa (cenários 6 e 8) foram classificados em primeiro lugar, uma vez que contribuíram de forma significativa com os serviços ecossistêmicos analisados. Portanto, a metodologia utilizada contribuiu com informações essenciais para a fase de diagnóstico e análise da elaboração de programas de Pagamento por Serviços Ambientais (PSA) para microbacias. / More than half of the native vegetation in Brazil occurs in private properties, this demonstrates the importance of the compatibilization of agricultural activities with the conservation of natural resources. The benefits generated by ecosystems for humans are defined as ecosystem services, which can be paid to encourage the maintenance and restoration of native vegetation on farms, with so-called Payment for Environmental Services (PES) programs. The methodology proposed in this study provides a step towards the spatial planning of the landscape in private properties, in order to increase the supply of ecosystem services, taking into account the perception of the decision makers in the land use management, through Multicriteria Decision Analysis (MCDA). The methodology was tested in the Cavalheiro stream microbasin, which is affected by habitat fragmentation and land conversion for agricultural purposes. The results showed that for hydrological ecosystem services, used by Brazilian PES programs, there should be a weighting between the regulation of the hydrological regime and the consequent decrease in the expected annual flow due to the increase of the forested area. In one of the land use and occupation scenarios, in which 51.8% of the microbasin was occupied by native vegetation, there was a decrease of 81.25% in surface runoff and 32.2% decrease in base runoff. However, this increase in vegetation cover proved to have the function of water regulation, increasing the contribution of the base flow to the total runoff of the watershed from 68% to 87%. This shows that the decision on the size of native vegetation areas must be based on the most demanding ecological functions, which for the case of the study area has been shown to be the support for biodiversity. The use of criteria weighting for multicriteria decision analysis (MCDA) has shown that microbasin decision makers are interested in new forms of land use management, aiming at regulating the hydrological regime, increasing support for biodiversity and landscapes that Bring greater potential to ecotourism activities. Thus, scenarios with larger areas of native vegetation (scenarios 6 and 8) were ranked first, since they contributed significantly to the ecosystem services analyzed. Therefore, the methodology used contributed with essential information for the diagnostic and analysis phase of the elaboration of Environmental Services Payment (PSA) programs for the Cavalheiro stream microbasin.

Amostras da água subterrânea foram coletadas em poços piezométricos localizados em dois transectos ao longo das vertentes e dois transectos ao longo da cabeceira de drenagem de uma microbacia experimental, durante o período de maio de 2005 a abril de 2006. Em cada transecto os poços piezométricos estavam localizados respectivamente na parte alta da vertente, sob floresta plantada de Eucalyptus, na meia encosta, sob mata ciliar, e adjacente ao riacho. As análises destas amostras também foram comparadas com a análise simultânea da água do riacho, coletada na calha da estação linimétrica da microbacia. As análises químicas incluíram principalmente nitrato (N-NO3 -) e amônio (N-NH4 +), além do ferro, silício, alumínio, carbono orgânico dissolvido (DOC) e pH. O objetivo foi inferir sobre aspectos do funcionamento hidrológico da zona ripária, em termos de alteração da concentração dos íons analisados entre os pontos amostrados. A fim de inferir sobre o efeito da vegetação e das características do solo nas modificações da água subterrânea ao longo da vertente, foi realizado inventário para determinação da área basal da vegetação e análise granulométrica e química do solo. Os principais resultados mostram que na zona ripária adjacente ao riacho há maior concentração de matéria orgânica no solo e de amônio na água subterrânea. As concentrações de amônio e nitrato na água do riacho foram sempre menores do que as concentrações nos piezômetros adjacentes ao riacho próximo ao vertedor. Isso indica que na zona ripária ocorrem modificações na água subterrânea que garantem a manutenção do ecossistema lótico. Também foi possível identificar diferenças ao longo da microbacia, entre a cabeceira de drenagem e a área próxima ao vertedor, o que demonstra que a zona ripária não é homogênea na área da microbacia. A geologia, a granulometria e o teor de matéria orgânica do solo, a precipitação, o aumento do nível freático e a influência da água subterrânea, foram os principais fatores de alteração das demais variáveis do estudo. / Groundwater samples were collected in piezometers located in two transects through the hillslope and two in the headwater of an experimental catchment from May 2005 to April 2006. In each transect there were one piezometer in the upland under the Eucalyptus planted forest, one piezometer at the middle slope in the riparian area, and the other piezometer was located by the stream with a total of 12 piezometers. The samples collected fortnightly were analyzed and compared with the stream water collected in the stream gauging station. The main variables analyzed were nitrate (N-NO3 -) and ammonium (N-NH4 +) as well as iron, silicon, aluminum, dissolved organic carbon (DOC) and pH. The objective was to infer about riparian zone hydrology, based on the difference among chemical composition of the samples. A characterization of the experimental catchment was performed from a vegetation inventory and soil analysis in order to assess the influence of soil properties and vegetation nutritional demand on the chemistry of the solutions. Chemical analyses demonstrated that in the riparian zone close to the stream soil organic matter content was higher than in other topographic positions as well as concentrations of ammonium in the groundwater throughout the year. The concentrations of ammonium and nitrate in the groundwater beside the stream were always higher. These results indicated that in riparian zone the modifications in the groundwater contribute to the lotic ecosystem maintenance. The results also indicated that the riparian zone is heterogeneous along the catchment area and that the behavior of headwater and downstream may be different. The geology, soil granulometric and organic matter level, precipitation and groundwater level were the main factors that influenced the studied variables.

Mais da metade da vegetação nativa no Brasil ocorrem em propriedades privadas, por isso a importância da compatibilização das atividades agropecuárias com a conservação dos recursos naturais. Os benefícios gerados pelos ecossistemas para os seres humanos são definidos como serviços ecossistêmicos, que podem ser pagos para incentivar a manutenção e restauração da vegetação nativa nas propriedades rurais, com os chamados programas de Pagamento por Serviços Ambientais (PSA). A metodologia proposta neste estudo proporciona um avanço no sentido do planejamento espacial da paisagem em propriedades privadas, a fim de aumentar o fornecimento de serviços ecossistêmicos, levando em conta a percepção dos tomadores de decisão no manejo do uso do solo, por meio de Análise de Decisão Multicritérios (MCDA). A metodologia foi testada na microbacia do córrego Cavalheiro, que é afetada pela fragmentação do habitat e conversão de terras para fins agrícolas. Os resultados mostraram que para os serviços ecossistêmicos hidrológicos, utilizados pelos programas de PSA brasileiros, deve existir uma ponderação entre a regulação do regime hidrológico com a consequente diminuição da vazão anual esperada devido ao incremento da área florestada. Em um dos cenários de uso e ocupação do solo, no qual se propôs a ocupação de 51,8 % da microbacia por vegetação nativa, houve uma diminuição de 81,25 % no escoamento superficial e de 32,2 % no escoamento de base. Entretanto, este aumento da cobertura vegetal provou ter a função de regulação hídrica, aumentando de 68 % para 87 % a contribuição da vazão de base no escoamento total da microbacia. Isso mostra que a decisão quanto ao tamanho das áreas de vegetação nativa deve ficar por conta das funções ecológicas mais exigentes, que para o caso da área de estudo mostrou ser o suporte à biodiversidade. O uso da ponderação dos critérios para a análise de decisão multicritério (MCDA) mostrou que os tomadores de decisão da microbacia estão interessados em novas formas de manejo de uso do solo, visando a regulação do regime hidrológico, aumento do suporte à biodiversidade e paisagens que tragam maior potencial às atividades de ecoturismo. Assim, os cenários com maiores áreas de vegetação nativa (cenários 6 e 8) foram classificados em primeiro lugar, uma vez que contribuíram de forma significativa com os serviços ecossistêmicos analisados. Portanto, a metodologia utilizada contribuiu com informações essenciais para a fase de diagnóstico e análise da elaboração de programas de Pagamento por Serviços Ambientais (PSA) para microbacias. / More than half of the native vegetation in Brazil occurs in private properties, this demonstrates the importance of the compatibilization of agricultural activities with the conservation of natural resources. The benefits generated by ecosystems for humans are defined as ecosystem services, which can be paid to encourage the maintenance and restoration of native vegetation on farms, with so-called Payment for Environmental Services (PES) programs. The methodology proposed in this study provides a step towards the spatial planning of the landscape in private properties, in order to increase the supply of ecosystem services, taking into account the perception of the decision makers in the land use management, through Multicriteria Decision Analysis (MCDA). The methodology was tested in the Cavalheiro stream microbasin, which is affected by habitat fragmentation and land conversion for agricultural purposes. The results showed that for hydrological ecosystem services, used by Brazilian PES programs, there should be a weighting between the regulation of the hydrological regime and the consequent decrease in the expected annual flow due to the increase of the forested area. In one of the land use and occupation scenarios, in which 51.8% of the microbasin was occupied by native vegetation, there was a decrease of 81.25% in surface runoff and 32.2% decrease in base runoff. However, this increase in vegetation cover proved to have the function of water regulation, increasing the contribution of the base flow to the total runoff of the watershed from 68% to 87%. This shows that the decision on the size of native vegetation areas must be based on the most demanding ecological functions, which for the case of the study area has been shown to be the support for biodiversity. The use of criteria weighting for multicriteria decision analysis (MCDA) has shown that microbasin decision makers are interested in new forms of land use management, aiming at regulating the hydrological regime, increasing support for biodiversity and landscapes that Bring greater potential to ecotourism activities. Thus, scenarios with larger areas of native vegetation (scenarios 6 and 8) were ranked first, since they contributed significantly to the ecosystem services analyzed. Therefore, the methodology used contributed with essential information for the diagnostic and analysis phase of the elaboration of Environmental Services Payment (PSA) programs for the Cavalheiro stream microbasin.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 116-126). Also available on the World Wide Web.

Thesis (doctoral)--Universiteit van Amsterdam, 1999. / Includes bibliographical references (p. 138-152).

Amostras da água subterrânea foram coletadas em poços piezométricos localizados em dois transectos ao longo das vertentes e dois transectos ao longo da cabeceira de drenagem de uma microbacia experimental, durante o período de maio de 2005 a abril de 2006. Em cada transecto os poços piezométricos estavam localizados respectivamente na parte alta da vertente, sob floresta plantada de Eucalyptus, na meia encosta, sob mata ciliar, e adjacente ao riacho. As análises destas amostras também foram comparadas com a análise simultânea da água do riacho, coletada na calha da estação linimétrica da microbacia. As análises químicas incluíram principalmente nitrato (N-NO3 -) e amônio (N-NH4 +), além do ferro, silício, alumínio, carbono orgânico dissolvido (DOC) e pH. O objetivo foi inferir sobre aspectos do funcionamento hidrológico da zona ripária, em termos de alteração da concentração dos íons analisados entre os pontos amostrados. A fim de inferir sobre o efeito da vegetação e das características do solo nas modificações da água subterrânea ao longo da vertente, foi realizado inventário para determinação da área basal da vegetação e análise granulométrica e química do solo. Os principais resultados mostram que na zona ripária adjacente ao riacho há maior concentração de matéria orgânica no solo e de amônio na água subterrânea. As concentrações de amônio e nitrato na água do riacho foram sempre menores do que as concentrações nos piezômetros adjacentes ao riacho próximo ao vertedor. Isso indica que na zona ripária ocorrem modificações na água subterrânea que garantem a manutenção do ecossistema lótico. Também foi possível identificar diferenças ao longo da microbacia, entre a cabeceira de drenagem e a área próxima ao vertedor, o que demonstra que a zona ripária não é homogênea na área da microbacia. A geologia, a granulometria e o teor de matéria orgânica do solo, a precipitação, o aumento do nível freático e a influência da água subterrânea, foram os principais fatores de alteração das demais variáveis do estudo. / Groundwater samples were collected in piezometers located in two transects through the hillslope and two in the headwater of an experimental catchment from May 2005 to April 2006. In each transect there were one piezometer in the upland under the Eucalyptus planted forest, one piezometer at the middle slope in the riparian area, and the other piezometer was located by the stream with a total of 12 piezometers. The samples collected fortnightly were analyzed and compared with the stream water collected in the stream gauging station. The main variables analyzed were nitrate (N-NO3 -) and ammonium (N-NH4 +) as well as iron, silicon, aluminum, dissolved organic carbon (DOC) and pH. The objective was to infer about riparian zone hydrology, based on the difference among chemical composition of the samples. A characterization of the experimental catchment was performed from a vegetation inventory and soil analysis in order to assess the influence of soil properties and vegetation nutritional demand on the chemistry of the solutions. Chemical analyses demonstrated that in the riparian zone close to the stream soil organic matter content was higher than in other topographic positions as well as concentrations of ammonium in the groundwater throughout the year. The concentrations of ammonium and nitrate in the groundwater beside the stream were always higher. These results indicated that in riparian zone the modifications in the groundwater contribute to the lotic ecosystem maintenance. The results also indicated that the riparian zone is heterogeneous along the catchment area and that the behavior of headwater and downstream may be different. The geology, soil granulometric and organic matter level, precipitation and groundwater level were the main factors that influenced the studied variables.

Harvesting of forested wetlands in the Atlantic and Gulf lower coastal plains has the potential to cause intense site disturbance. Often, as a result of poor pre-harvest planning, silvicultural activities are performed on wetland soils highly susceptible to rutting and puddling. Potential decreases in pine productivity have been connected with increased soil strength and decreased aeration that are commonly remnants of site disturbances associated with wet-weather harvesting. A simple and economical rating system is needed to identify soils susceptible to disturbance by various types of equipment. The use of such a system could lower the impact on wetland soils and lower the cost of extensive site preparation methods. Logging efficiency and operational productivity could also be increased by identifying equipment types compatible with site conditions. The purpose of this study was to characterize and model soil strength as a function of soil physical properties and site characteristics. The soil strength model was subsequently used to develop a trafficability hazard index. Forested wetland sites in the South Carolina coastal plain were characterized to develop the trafficability hazard index. The study site consisted of three blocks located on poorly drained loblolly pine plantations. Five sequences of measurements were taken consisting of soil moisture, water table depth, and soil strength. The five sequences of measurements were taken over a wide range of soil moisture contents and water table depths to characterize the effects on soil strength. Bulk density, porosity, texture, organic matter, and hydraulic conductivity were also determined to characterize the blocks and identify effects on soil strength. Evaluating the effects of these properties on soil strength identified two relatively easily determined soil properties that could be used for the trafficability index. Volumetric moisture content and penetration resistance of the A horizon were used due to their relationships with trafficability and ease of determination. Estimates of pressure applied to the soil by harvesting equipment were used to find the limits of the sandy loam A horizon to support various types of equipment. Equipment pressures were compared to soil penetration resistance pressures estimated by soil moisture. The trafficability hazard index presented used general ground pressures for various harvesting equipment, but use of specific equipment pressures would provide the best results. Using the trafficability hazard index, sites with less than optimal conditions for traffic can be avoided or special harvesting equipment can be identified to limit site disturbance. / Master of Science