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Karolina Villagra-Mendoza
Agricultural Engineering, Instituto Tecnologico de Costa Rica, 27942 Cartago, Cartago Costa Rica

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Journal article
Published: 30 September 2020 in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
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In this work, we apply close-range photogrammetry with unmanned aircraft systems to quantify erosion with millimetric spatial resolution in agricultural plots. We evaluate the proposed methodology against the traditional runoff method on active plots. A database of digital elevation models was constructed with a ground sampling distance of 7 mm/pixel and maximum root-mean-square total error of 4.8 mm, which allowed the follow-up of soil erosion dynamics within the runoff plots for a period of three months. Good agreement of the photogrammetric estimations with respect to field measurements was observed, whereas it provides a more detailed spatial information that can be used for precise soil loss dynamic studies.

ACS Style

Sergio Alberto Arriola-Valverde; Luis Carlos Villalobos-Avellan; Karolina Villagra-Mendoza; Renato Rimolo-Donadio. Erosion Quantification in Runoff Agriculture Plots by Multitemporal High-Resolution UAS Digital Photogrammetry. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2020, 13, 6326 -6336.

AMA Style

Sergio Alberto Arriola-Valverde, Luis Carlos Villalobos-Avellan, Karolina Villagra-Mendoza, Renato Rimolo-Donadio. Erosion Quantification in Runoff Agriculture Plots by Multitemporal High-Resolution UAS Digital Photogrammetry. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 2020; 13 (99):6326-6336.

Chicago/Turabian Style

Sergio Alberto Arriola-Valverde; Luis Carlos Villalobos-Avellan; Karolina Villagra-Mendoza; Renato Rimolo-Donadio. 2020. "Erosion Quantification in Runoff Agriculture Plots by Multitemporal High-Resolution UAS Digital Photogrammetry." IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 13, no. 99: 6326-6336.

Journal article
Published: 27 February 2020 in Revista Tecnología en Marcha
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En la cuenca del río La Estrella la deforestación en las partes altas y bajas del río, han debilitado la capacidad de retención de material de la cuenca, aumentando la frecuencia y capacidad destructiva de las descargas extremas. Adicionalmente, el terremoto de Limón en el año 1991, provocó una alteración geológica especialmente en el Valle La Estrella, modificando la dinámica tradicional y estabilidad de su cauce. Específicamente, el sector de río objeto de este estudio presenta dos agravantes: un asentamiento y la única vía de acceso terrestre muy cerca del cauce, lo que significa mayor riesgo para el poblado y en consecuencia es necesario realizar obras de protección. Para esto, se han comparado los resultados de los modelos hidráulicos en 1D y 2D con el fin de evidenciar la importancia de la información y su análisis para la toma de decisiones en lo referente al diseño de obras en el río.

ACS Style

Fernando Watson; Isabel Guzmán-Arias; Karolina Villagra-Mendoza. Estudio de caso: Análisis de parámetros de diseño para obras mediante una modelación hidráulica en la planicie de inundación de un tramo del río La Estrella, Limón Costa Rica. Revista Tecnología en Marcha 2020, ág. 44 -54.

AMA Style

Fernando Watson, Isabel Guzmán-Arias, Karolina Villagra-Mendoza. Estudio de caso: Análisis de parámetros de diseño para obras mediante una modelación hidráulica en la planicie de inundación de un tramo del río La Estrella, Limón Costa Rica. Revista Tecnología en Marcha. 2020; ():ág. 44-54.

Chicago/Turabian Style

Fernando Watson; Isabel Guzmán-Arias; Karolina Villagra-Mendoza. 2020. "Estudio de caso: Análisis de parámetros de diseño para obras mediante una modelación hidráulica en la planicie de inundación de un tramo del río La Estrella, Limón Costa Rica." Revista Tecnología en Marcha , no. : ág. 44-54.

Journal article
Published: 10 January 2020 in Applied Sciences
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Biochar is a carbon-rich organic material, obtained by the thermochemical conversion of biomass in an oxygen-limited environment, used as a soil amendment to stimulate soil fertility and improve soil quality. There is a clear need in developing countries for access to low cost, low technology options for biochar production, for example, top-lit updraft (TLUD) stoves, which are popular and spread worldwide. However, TLUD biochars are inevitably very variable in their properties for a variety of reasons. We present laboratory triplicate tests carried out on TLUD biochars obtained from waste pinewood and a Guadua bamboo. Analyzed properties include specific surface area (A-BET), porosity, skeletal density, hydrophobicity, proximal and elemental composition, cation exchange capacity (CEC), relative liming capacity and pH. SEM images of the bamboo and wood biochars are compared. The biochars were mixed with composted human excreta at 5% and 10% biochar content, and available water content (AWC) was analyzed. Operating temperatures in the TLUD were recorded, showing different behaviors among the feedstocks during the process. Differences in operating temperatures during charring of the bamboo samples seem to have led to differences in A-BET, hydrophobicity and CEC, following unprecedented trends. For the mixtures of the biochars with compost, at 5% biochar no significant differences were observed for AWC. However, in the 10% biochar mixtures, bamboo biochar showed an unexpectedly high AWC. Overall, variations of chemical and physical properties between bamboo biochars were greater, while pinewood biochars showed similar properties, consistent with more homogeneous charring temperatures.

ACS Style

Federico Masís-Meléndez; Diana Segura-Chavarría; Carlos A García-González; Jaime Quesada-Kimsey; Karolina Villagra-Mendoza. Variability of Physical and Chemical Properties of TLUD Stove Derived Biochars. Applied Sciences 2020, 10, 507 .

AMA Style

Federico Masís-Meléndez, Diana Segura-Chavarría, Carlos A García-González, Jaime Quesada-Kimsey, Karolina Villagra-Mendoza. Variability of Physical and Chemical Properties of TLUD Stove Derived Biochars. Applied Sciences. 2020; 10 (2):507.

Chicago/Turabian Style

Federico Masís-Meléndez; Diana Segura-Chavarría; Carlos A García-González; Jaime Quesada-Kimsey; Karolina Villagra-Mendoza. 2020. "Variability of Physical and Chemical Properties of TLUD Stove Derived Biochars." Applied Sciences 10, no. 2: 507.

Journal article
Published: 20 December 2019 in Revista Tecnología en Marcha
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Techos verdes se refiere a la práctica de recubrir con una capa vegetal el techo de una estructura. A pesar de que esta estructura ha formado parte del paisaje arquitectónico característico de las tierras del norte afectadas por crudos inviernos hoy en día se ha presentado con gran auge en la arquitectura moderna. Su importancia, desde el ámbito hidrológico, radica en la capacidad que poseen para modificar el comportamiento hidrológico de un techo, de una zona y, por tanto, de una cuenca. Con el fin de cuantificar este comportamiento característico de un techo verde se llevaron a cabo una serie de pruebas con diferentes intensidades en un simulador de lluvia previamente calibrado, utilizando un techo verde de 3 metros cuadrados y eventos de precipitación desde 8 hasta 36 mm/h. Se cuantificó el volumen de agua de lluvia despejado por cada una de las capas que conformaron el techo verde. De esto se derivó que el tipo de sustrato instalado es un factor primordial para estimar el comportamiento hidráulico de la estructura ya que esta depende enteramente de la capacidad de conducción hidráulica del sustrato instalado para evitar la conformación de anegamientos en la superficie, aunado a esto, se encontró que las variaciones en la pendiente de instalación e intensidad de evento de precipitación no causaron una variación drástica sobre la curva de comportamiento del techo verde, pero sí en el volumen entregado por cada una de las capas que lo conforman.

ACS Style

Emmanuel Rodríguez-Bejarano; Karolina Villagra-Mendoza. Evaluación de un techo verde bajo eventos de precipitación sintéticos para caracterizar el comportamiento del flujo por escorrentía. Revista Tecnología en Marcha 2019, ág. 3 -12.

AMA Style

Emmanuel Rodríguez-Bejarano, Karolina Villagra-Mendoza. Evaluación de un techo verde bajo eventos de precipitación sintéticos para caracterizar el comportamiento del flujo por escorrentía. Revista Tecnología en Marcha. 2019; ():ág. 3-12.

Chicago/Turabian Style

Emmanuel Rodríguez-Bejarano; Karolina Villagra-Mendoza. 2019. "Evaluación de un techo verde bajo eventos de precipitación sintéticos para caracterizar el comportamiento del flujo por escorrentía." Revista Tecnología en Marcha , no. : ág. 3-12.

Journal article
Published: 23 October 2019 in Revista Tecnología en Marcha
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En Costa Rica el caudal ambiental se calcula como un 10% del aforo caudal medio del río. Este porcentaje ha carecido de fundamento científico en relación con las condiciones fluviales aptas para preservar los ecosistemas presentes en los cauces. Las concesiones de agua para los diferentes usos han provocado un impacto en disponibilidad de agua para algunos lugares y épocas del año y en la calidad del recurso transformando las condiciones fisicoquímicas y ecológicas de los cauces. Del sistema fluvial del río Birrís, se concesiona un 20% para uso consuntivo como producción agrícola, humano y riego, y el restante se utiliza para la generación hidroeléctrica. Debido a la baja calidad de sus aguas a la fecha no existen especies indicadoras lo que imposibilita el uso de enfoques que tomen en cuenta los ecosistemas para generar curvas de preferencia. El presente trabajo utilizó un enfoque hidrológico para determinar el caudal ambiental del río Birrís usando la metodología de curva de duración de caudales. Se basó en el análisis de series de datos de clima obtenidas por 10 años y series de caudales diarios de un periodo de tres años. Se realizaron tres aforos de biota y flujo en tres puntos distribuidos a lo largo del cauce principal distribuidos en un periodo de un año. Finalmente, se determinó el caudal ambiental para un régimen de flujo basado en valores medios mensuales.

ACS Style

Isabel Guzmán-Arias; Fernando Watson; Karolina Villagra-Mendoza. Determinación del caudal ambiental en el río Birrís, Costa Rica. Revista Tecnología en Marcha 2019, ág. 18 -27.

AMA Style

Isabel Guzmán-Arias, Fernando Watson, Karolina Villagra-Mendoza. Determinación del caudal ambiental en el río Birrís, Costa Rica. Revista Tecnología en Marcha. 2019; ():ág. 18-27.

Chicago/Turabian Style

Isabel Guzmán-Arias; Fernando Watson; Karolina Villagra-Mendoza. 2019. "Determinación del caudal ambiental en el río Birrís, Costa Rica." Revista Tecnología en Marcha , no. : ág. 18-27.

Journal article
Published: 25 September 2019 in Soil Systems
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Biochar impacts soil-water related processes such as infiltration and contributes to the hydrological response of catchments. The aim of this work is to determine the impact of wetting and drying conditions on the infiltration behavior of two biochar amendments and to validate the performance of three infiltration models: Kostiakov, Horton, and Philips. Two materials, sand and a sandy loam, were mixed with 0%, 2.5%, and 5% (by dry wt.) mango wood biochar produced at a highest heating rate of 600 °C and with a particle size of

ACS Style

Karolina Villagra-Mendoza; Rainer Horn. Changes in Water Infiltration after Simulated Wetting and Drying Periods in two Biochar Amendments. Soil Systems 2019, 3, 63 .

AMA Style

Karolina Villagra-Mendoza, Rainer Horn. Changes in Water Infiltration after Simulated Wetting and Drying Periods in two Biochar Amendments. Soil Systems. 2019; 3 (4):63.

Chicago/Turabian Style

Karolina Villagra-Mendoza; Rainer Horn. 2019. "Changes in Water Infiltration after Simulated Wetting and Drying Periods in two Biochar Amendments." Soil Systems 3, no. 4: 63.

Journal article
Published: 01 July 2018 in International Agrophysics
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Water and solute transports in the vadose zone depend on the distribution, size, shape and configuration of the pores. They affect the soil hydraulic properties and, consequently, the directly related processes such as water storage, infiltration, groundwater recharge, and also erosion and runoff. Soils amended with biochar are prompt to improve their physical and hydraulic properties. Biochar addition alters not only porosity, the water retention pattern and the derived pore distribution, but also the hydraulic conductivity under saturated and unsaturated conditions. In our work, two different doses (2.5 and 5% dry wt.) were added to two textured soils (sand and sandy loam). The unsaturated hydraulic conductivity and saturated hydraulic conductivity were measured under laboratory conditions. The obtained results show the positive effect of biochar on the hydraulic functions. For the sandy soil, the higher the dose of biochar, the more constant and relatively higher is the hydraulic conductivity up to - 40 kPa. At less negative matric potentials (< -10 kPa), the unamended sandy loam soil showed a slightly higher unsaturated hydraulic conductivity, compared to the amended soils. These results underline that biochar addition enhances the transport of water under unsaturated conditions by reducing the formation of larger pores while also intensifying the finer inter-particle pore formation.

ACS Style

Karolina Villagra-Mendoza; Rainer Horn. Effect of biochar on the unsaturated hydraulic conductivity of two amended soils. International Agrophysics 2018, 32, 373 -378.

AMA Style

Karolina Villagra-Mendoza, Rainer Horn. Effect of biochar on the unsaturated hydraulic conductivity of two amended soils. International Agrophysics. 2018; 32 (3):373-378.

Chicago/Turabian Style

Karolina Villagra-Mendoza; Rainer Horn. 2018. "Effect of biochar on the unsaturated hydraulic conductivity of two amended soils." International Agrophysics 32, no. 3: 373-378.

Journal article
Published: 22 April 2018 in Geoderma
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Land degradation reduces soil productivity and exacerbates the problem of food security. Thus, there is an increasing need to look for sustainable farming practices aimed to water and soil conservation. In this regards, conditioning the soil with biochar has been identified as a possible means on improving water conservation and soil biochemical, physical, i.e. mechanical and hydraulic characteristics. Many studies demonstrate these effects of biochar. However, the extended number of variables influencing its impact require further measurements. The objective of this study is to determine the effect of wood-based biochar on two different textured soils and to evaluate their influence on some hydrological properties: water retention, shrinkage behavior and the effect of wetting and drying periods on the hydraulic conductivity. Test samples were prepared by adding 2.5 and 5% (by dry mass) of pyrolyzed mango-wood biochar to a sand and a sandy loam. Soil water retention and soil shrinkage curves were measured. Additionally, extra core samples were exposed to four intense cycles of wetting and drying, by drying the samples at 30 °C for three consecutive days. Biochar amendments increased water retention in the coarse textured sand compared to the unamended soil. Pore size distribution was significantly altered in the sandy substrate, reducing the fraction of wide coarse pores and increasing meso porosity. Repeated wetting and drying cycles enhanced the structural stability of the pore system increasing the saturated hydraulic conductivity. Soil rigidity, especially in the sandy mixtures, was enhanced by the addition of biochar, forming an internal pore structure able to resist better hydraulic deformation due to drying. These results confirm the suitability of biochar to overcome extreme hydrological conditions.

ACS Style

Karolina Villagra-Mendoza; Rainer Horn. Effect of biochar addition on hydraulic functions of two textural soils. Geoderma 2018, 326, 88 -95.

AMA Style

Karolina Villagra-Mendoza, Rainer Horn. Effect of biochar addition on hydraulic functions of two textural soils. Geoderma. 2018; 326 ():88-95.

Chicago/Turabian Style

Karolina Villagra-Mendoza; Rainer Horn. 2018. "Effect of biochar addition on hydraulic functions of two textural soils." Geoderma 326, no. : 88-95.