Browsing by Author "Carkovic Aguilera, Athena B."

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    Dynamics of metals in street dust after a mudslide: Case of mining city in Chile
    (2019) Vega Contreras, Alejandra Soledad; Arce, Guillermo; Carkovic Aguilera, Athena B.; Moya, Pablo; Coquery, Marina; Pastén González, Pablo Arturo; CEDEUS (Chile)
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    Sediment composition for the assessment of water erosion and nonpoint source pollution in natural and fire-affected landscapes
    (2014) Carkovic Aguilera, Athena B.; Bonilla Meléndez, Carlos Alberto; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    La erosión hídrica es una de las principales causas de la degradación del suelo y es un gran agente causante de la contaminación de fuente difusa o no puntual. Se han realizado numerosos esfuerzos para mejorar las estimaciones de despegue, transporte y sedimentación de suelo en laderas agrícolas, así como para estimar la cantidad y distribución de tamaño del sedimento que abandona un terreno. Los modelos de erosión multi-class, como WEPP y RUSLE2, subdividen el suelo erodado en diferentes tamaños y estiman la composición de los agregados del suelo basados en ecuaciones empíricas. Estas ecuaciones fueron derivadas a partir de suelos agrícolas, y hasta ahora no han sido probadas en condiciones diferentes. Por lo tanto, el objetivo de este estudio fue evaluar estas ecuaciones en muestras de suelo obtenidas de paisajes naturales (suelos no cultivados) y afectados por incendios y, de ser necesario, desarrollar un nuevo set de ecuaciones que se ajusten mejor a estas condiciones. Se realizaron análisis químicos, físicos, y de composición del sedimento y sus agregados en una serie de muestras de suelo obtenidas de la Patagonia Chilena, y luego se compararon con las estimaciones obtenidas de las ecuaciones. Los resultados mostraron que las fracciones del sedimento no fueron determinadas con precisión por las ecuaciones empíricas.
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    Sediment composition for the assessment of water erosion and nonpoint source pollution in natural and fire-affected landscapes
    (2015) Carkovic Aguilera, Athena B.; Pastén González, Pablo Arturo; Bonilla Meléndez, Carlos Alberto; CEDEUS (Chile)
    Water erosion is a leading cause of soil degradation and a major nonpoint source pollution problem. Many efforts have been undertaken to estimate the amount and size distribution of the sediment leaving the field. Multi-size class water erosion models subdivide eroded soil into different sizes and estimate the aggregates composition based on empirical equations derived from agricultural soils. The objective of this study was to evaluate these equations on soil samples collected from natural landscapes (uncultivated) and fire-affected soils. Chemical, physical, and soil fractions and aggregate composition analyses were performed on samples collected in the Chilean Patagonia and later compared with the equations' estimates. The results showed that the empirical equations were not suitable for predicting the sediment fractions. Fine particles, including primary clay, primary silt, and small aggregates (<53 mu m) were over-estimated, and large aggregates (>53 mu m) and primary sand were under-estimated. The uncultivated and fire-affected soils showed a reduced fraction of fine particles in the sediment as clay and silt were mostly in the form of large aggregates. Thus, a new set of equations was developed for these soils, where small aggregates were defined as particles with sizes between 53 mu m and 250 mu m and large aggregates as particles >250 mu m. With r(2) values between 0.47 and 0.98, the new equations provided better estimates for primary sand and large aggregates. The aggregate's composition was also well predicted, especially the silt and clay fractions in the large aggregates from uncultivated soils (r(2) = 0.63 and 0.83, respectively) and the fractions of silt in the small aggregates (r(2) = 0.84) and clay in the large aggregates (r(2) = 0.78) from fire-affected soils. Overall, these new equations proved to be better predictors for the sediment and aggregate's composition in uncultivated and fire-affected soils, and they reduce the error when estimating soil loss in natural landscapes.
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    Spatial discretization of large watersheds and its influence on the estimation of hillslope sediment yield
    (2016) González, Virginia I.; Carkovic Aguilera, Athena B.; Lobo, Gabriel P.; Flanagan, Dennis C.; Bonilla Meléndez, Carlos Alberto