Mudflow Modeling in the Copiapó Basin, Chile

[EN] Extreme precipitation events that occurred between March 24 and March 26 of 2015 in the region of the Atacama Desert (26-29°S) left around 30 000 victims, being one of the biggest events over the past 50 years, with total a cost of reconstruction of about 1.5 billion dollars. The mudflows which increased during the flashflood inundated much of the city of Copiapó and Tierra Amarilla. This manuscript aims to model the mudflow of March 2015 in the Río Copiapó, specifically in the towns of Copiapó and Tierra Amarilla. The modeling process is performed using the Rapid Mass Movement Simulation Model (RAMMS) that allows modeling the dynamics of the mudflow in two dimensions, only using the topographic features of the modeling domain. Calibration of the model was carried out successfully using data from inundation heights captured around the city after the 2015 event. A detailed analysis of the hydrometeorological event is carried out using satellite images obtained from Multi-satellite Precipitation Analysis (TMPA), and pluviometric and hydrographic data available in the Copiapó River basin. The simulation of the flood is reproduced with maps of inundation heights associated with two modeling scenarios. The maximum flood heights are ultimately used for developing risk maps at both sites. According to our results, the RAMMS model is an appropriate tool for modeling mudflow and mapping flood risk to improve hydrological risk management in arid and semiarid basins of Chile[ES] Los eventos extremos de precipitación intensa que se produjeron entre el 24 y 26 de marzo de 2015 en la región del Desierto de Atacama (26-29°S), en el Norte de Chile, dejaron alrededor de 30 000 damnificados, siendo uno de los eventos de mayores magnitudes de los últimos 50 años, y que tuvo un costo de reconstrucción de alrededor de $1.5 billones de dólares. Los flujos de detritos que se incrementaron durante la crecida inundaron gran parte de las ciudades de Copiapó y Tierra Amarilla. Este manuscrito tiene por objetivo modelar la crecida aluvional de marzo de 2015 en la cuenca del Río Copiapó, específicamente en las localidades de Copiapó y Tierra Amarilla. La modelación se lleva a cabo utilizando el modelo Rapid Mass Movement Simulation (RAMMS) que permite modelar la dinámica de la crecida aluvional en dos dimensiones, utilizando las características topográficas de los dominios de modelación. La calibración del modelo fue llevada a cabo satisfactoriamente utilizando datos de alturas capturados en terreno después de la crecida del año 2015. Un análisis detallado del evento hidrometeorológico es llevado a cabo utilizando imágenes satelitales obtenidas desde Multi-satellite Precipitation Analysis (TMPA), así como datos pluviométricos e hidrográficos disponibles en la cuenca del Río Copiapó. La simulación de la crecida es reproducida con mapas de alturas de inundación asociados a dos escenarios de modelación. Las alturas máximas de inundación son finalmente utilizadas para el desarrollo de mapas de riesgos en ambas localidades. De acuerdo a nuestros resultados, el modelo RAMMS es una herramienta apropiada para modelar crecidas aluvionales y elaborar mapas de riesgos de inundación para mejorar la gestión de riesgos hidrológicos en cuencas áridas y semiáridas de Chile.Los autores de este manuscrito agradecen el financiamiento proporcionado por La Fundación Centro Nacional del Medio Ambiente de Chile (CENMA) para llevar a cabo este estudio. Adicionalmente, se agradece la contribución de datos de alturas de inundación proporcionados por Tatiana Izquierdo (académica de la Universidad de Atacama) los cuales permitieron la calibración del modelo RAMMS.Valdés-Pineda, R.; Valdés, JB.; García-Chevesich, P. (2017). Modelación de Crecidas Aluvionales en la Cuenca del Río Copiapó, Chile. Ingeniería del Agua. 21(2):135-152. doi:10.4995/ia.2017.7366.SWORD135152212Abrams, M. 2000. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER): data products for the high spatial resolution imager on NASA's Terra platform. International Journal of Remote sensing, 21(5), 847-859. https://doi.org/10.1080/014311600210326Barrett, B. S., Campos, D. A., Veloso, J. V., Rondanelli, R. 2016. Extreme temperature and precipitation events in March 2015 in central and northern Chile. Journal of Geophysical Research: Atmospheres, 121(9): 4563-4580. https://doi.org/10.1002/2016jd024835Bontemps, S., Defourny, P., Bogaert, E. V., Arino, O., Kalogirou, V., Perez, J. R. 2011. GLOBCOVER 2009-Products description and validation report.Bozkurt, D., Rondanelli, R., Garreaud, R., Arriagada, A. 2016. Impact of warmer eastern tropical Pacific SST on the March 2015 Atacama floods. Monthly Weather Review, 144(11), 4441-4460. https://doi.org/10.1175/MWR-D-16-0041.1Christen, M., Bartelt, P., Kowalski, J., Stoffel, L. 2008. Calculation of dense snow avalanches in three-dimensional terrain with the numerical simulation program RAMMS. In Proceedings Whistler 2008 International Snow Science Workshop, September 21-27, 2008 (p. 709).Christen, M., Kowalski, J., Bartelt, P. 2010. RAMMS: numerical simulation of dense snow avalanches in three-dimensional terrain. Cold Regions Science and Technology, 63(1), 1-14. https://doi.org/10.1016/j.coldregions.2010.04.005Ferrando, R., Fuentes, F., Coloma, F., Merino. 2015. Efectos Geológicos del Evento Meteorológico del 24 y 25 de marzo De 2015: Fotointerpretación y Reconocimiento en Terreno del Efecto de Aluviones e Inundaciones en las zonas de Tierra Amarilla y Nantoco: Zona de Inundación y zonas propuestas para Evacuación, Campamento y Acopio. SERNAGIOMIN.Izquierdo, T., Abad, M. Bernárdez, E. 2016. Catastrophic flooding caused by a mudflow in the urban area of Copiapó (Atacama Desert, northern Chile). International Conference on Urban Risks.MOP-DGA, C. I. 2004. Diagnóstico y clasificación de los cursos y cuerpos de agua según objetivo de calidad. Cuenca Quebrada de Tarapacá. Santiago, Chile.Naranjo, J. A., Olea-Encina, P. 2015. Descargas aluviales durante la tormenta del desierto de Atacama en marzo de 2015, Chile. SERNAGIOMIN.Pizarro-Tapia, R., Valdés-Pineda, R., Olivares, C., González, P. A. 2014. Development of Upstream Data-Input Models to Estimate Downstream Peak Flow in Two Mediterranean River Basins of Chile. Open Journal of Modern Hydrology, 4(4), 132-143. https://doi.org/10.4236/ojmh.2014.44013Quan, L. 2012. Dynamic numerical run-out modeling for quantitative landslide risk assessment. Thesis of University of Twente, ITC, 206:1-237.Raïmat, C., Riera, E., Graf, C., Luis-Fonseca, R., Fañanás, C., Hurlimann Ziegler, M. 2013. Experiencia de la aplicación de RAMMS para la modelización de flujo tras la aplicación de las soluciones flexibles VX en el barranc de Portainé. In VIII Simposio Nacional sobre Taludes y Laderas Inestables, 1131-1144. Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE).Tachikawa, T., Hato, M., Kaku, M., Iwasaki, A. 2011. Characteristics of ASTER GDEM version 2. In Geoscience and Remote Sensing Symposium (IGARSS), 2011 IEEE International, 3657-3660. https://doi.org/10.1109/IGARSS.2011.6050017Valdés-Pineda, R., Valdés, J. B., Diaz, H. F., Pizarro-Tapia, R. 2016. Analysis of spatio-temporal changes in annual and seasonal precipitation variability in South America-Chile and related ocean-atmosphere circulation patterns. International Journal of Climatology, 36(8), 2979-3001. https://doi.org/10.1002/joc.4532Valdés-Pineda, R., Cañón, J., Valdés, J. B. 2017. 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WEBSEIDF: A web-based system for the estimation of IDF curves in Central Chile

The lack of reliable continuous rainfall records can exacerbate the negative impact of extreme storm events. The inability to describe the continuous characteristics of rainfall from storm events increases the likelihood that the design of hydraulic structures will be inadequate. To mitigate extreme storm impacts and improve water governance at the catchment scale, it is vital to improve the availability of data and the array of tools used to model and forecast hydrological processes. In this paper, we describe and discuss the implementation of a web-based system for the estimation of intensity–duration–frequency (IDF) curves (WEBSEIDF) in Chile. The web platform was constructed using records from 47 pluviographic gauges available in central Chile (30–40° S), with at least 15 years of reliable records. IDF curves can be generated for durations ranging from 15 min to 24 h. In addition, the extrapolation of rainfall intensity from pluviograph to pluviometric gauges (i.e., 24-h rainfall accumulation) can be carried out using the storm index (SI) method. IDF curves can also be generated for any spatial location within central Chile using the ordinary Kriging method. These procedures allow the generation of numerical and graphical displays of IDF curves, for any selected spatial location, and for any combination of probability distribution function (PDF), parameter estimation method, and type of IDF model. One of the major advantages of WEBSEIDF is the flexibility of its database, which can be easily modified and saved to generate IDF curves under user-defined scenarios, that is, changing climate conditions. The implementation and validation of WEBSEIDF serves as a decision support system, providing an important tool for improving the ability of the Chilean government to mitigate the impact of extreme hydrologic events in central Chile. The system is freely available for students, researchers, and other relevant professionals, to improve technical decisions of public and private institutions

Spatial and temporal analysis of rainfall concentration using the Gini index and PCI

This study aims to determine if there is variation in precipitation concentrations in Chile. We analyzed daily and monthly records from 89 pluviometric stations in the period 1970–2016 and distributed between 29°12′ S and 39°30′ S. This area was divided into two climatic zones: arid–semiarid and humid–subhumid. For each station, the Gini coefficient or Gini Index (GI), the precipitation concentration index (PCI), and the maximum annual precipitation intensity in a 24-h duration were calculated. These series of annual values were analyzed with the Mann–Kendall test with 5% error. Overall, it was noted that positive trends in the GI are present in both areas, although most were not found to be significant. In the case of PCI, the presence of positive trends is only present in the arid–semiarid zone; in the humid–subhumid zone, negative trends were mostly observed, although none of them were significant. Although no significant changes in all indices are evident, the particular case of the GI in the humid–subhumid zone stands out, where mostly positive trends were found (91.1%), of which 35.6% were significant. This would indicate that precipitation is more likely to be concentrated on a daily scale

Morphological characterization of sweet chestnut fruits from forest plantations in central Chile

The sweet chestnut (Castanea sativa Mill.) is one of the most important starchy foods worldwide due to its low fat content and high nutritional value. This study is the first analysis of the sweet chestnut fruit in forest plantations where the morphological properties are characterized, in terms of caliber, size, shape, and internal cracking, damage, and cavities. The study was based in three sites in Chile, Los Rios Region (39°S), where most of the forest chestnut plantations are located. Scott and Knott test of variance and contingency tables were used as statistical methods for site comparisons. In general, no significant differences in size were found among sites. Moreover, the Chilean forest sweet chestnut can be defined as a small-caliber fruit with slight internal cracking and internal damage and almost no cavities. Therefore, due to its morphological characteristic (especially caliber), it has the potential to be used for secondary food products.El castaño (Castanea sativa Mill.) es uno de los frutos almidonados más importantes a nivel global dado su bajo contenido de grasas y alto valor nutricional. En el presente estudio, se caracterizó morfológicamente al fruto del castaño en términos de su calibre, su tamaño (i.e. largo, ancho y grosor), su forma (R1 como la relación entre el ancho sobre el largo y R2 como la relación entre el ancho y el grosor), y también su partición interna, el daño interno y su cavidad interna. El estudio se desarrolló sobre tres rodales ubicados en la Región de Los Rios, Chile (39°S), lugar que concentra la mayor superficie de castaño en Chile. Los rodales se compararon estadísticamente usando la prueba de prueba de Scott y Knott, además de tablas de contingencia. En general, no se encontraron diferencias significativas entre rodales. Asimismo, el fruto del castaño estudiado puede ser definido como de calibre pequeño, con una baja partición y daño interno, además de casi nula cavidad. Por lo tanto y dado los resultados (especialmente el de calibre), el fruto analizado proveniente de rodales con fines madereros, tiene un alto potencial como productos secundario, como por ejemplo para mermelada, puré de castañas y harina

The First Drying Lake in Chile: Causes and Recovery Options

Located southwest of the city of Santiago (Chile), the Aculeo Lagoon used to be an important body of water, providing environmental, social, and economic services to both locals (mostly drinking water and small-scale agricultural irrigation) and tourists who visited the area for fishing, sailing, and other recreational activities. The lagoon dried completely in May of 2018. The phenomenon has been attributed to the current climatic drought. We implemented and calibrated a surface-groundwater model to evaluate the hydrogeologic causes of the lagoon's disappearance, and to develop feasible solutions. The lagoon's recovery requires a series of urgent actions, including environmental education and significant investment in infrastructure to import water. Ultimately, there are two goals: bringing back historic water levels and ensuring the sustainability of water resources at the catchment scale.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

A system to evaluate fire impacts from simulated fire behavior in Mediterranean areas of Central Chile

Wildfires constitute the greatest economic disruption to Mediterranean ecosystems, from a socio-economic and ecological perspective (Molina et al., 2014). This study proposes to classify fire intensity levels based on potential fire behavior in different types of Mediterranean vegetation types, using two geographical scales. The study considered > 4 thousand wildfires over a period of 25 years, identifying fire behavior on each event, based on simulations using “KITRAL”, a model developed in Chile in 1993 and currently used in the entire country. Fire intensity values allowed results to be classified into six fire effects categories (levels), each of them with field indicators linking energy values with damage related to burned vegetation and wildland urban interface zone. These indicators also facilitated a preliminary assessment of wildfire impact on different Mediterranean land uses and, are therefore, a useful tool to prioritize future interventions

LATITUDINAL ANALYSIS OF RAINFALL INTENSITY AND MEAN ANNUAL PRECIPITATION IN CHILE

The study and analysis of precipitation has become a crucial tool in understanding the temporal and spatial behavior of water resources, in terms of availability and impact on extreme events. The objective of this study was to evaluate different rainfall parameters (intensities for 1-h duration D = 1 h and return periods of T = 5 and 100 yr, and mean annual precipitation) for different latitudinal and climatic zones in Chile. We analyzed the information recorded on thousands of pluvial bands and rain gauges for 49 stations; this because it is unclear how rainfall intensities change along the country (though total amounts do), in addition to a lack of literature focused on ranges and amounts on the behavior of rainfall variables. The Gumbel probability distribution function (PDF) and mathematical rainfall intensity formulas were used to develop intensity-duration-frequency (IDF) curves for each station. Maximum and minimum rainfall intensity values for T = 100 yr ranged from 8.79 (hyperarid zone) to 40.17 mm h-1 (subhumid-humid zone). Total annual rainfall values ranged between 43.9 (hyperarid zone) and 3891.0 mm yr-1 (humid zone). Additionally, the real maximum intensity registered on each station was analyzed, determining its exceedance probability. Likewise, multiple comparisons were made to detect significant differences between the gauge stations and different climatic zones using the Kruskal Wallis test (alpha = 0.05). Differences between maximum and minimum values registered for all stations were as much as 80 times for total rainfall amounts and 4.5 times for rainfall intensities (T = 100 yr). However, maximum rainfall intensities values were similar at different latitudes, suggesting the absence of correlation between maximum rainfall intensity and annual rainfall amount, as the latter variable increased gradually with latitude

Comparing Methods for the Regionalization of Intensity−Duration−Frequency (IDF) Curve Parameters in Sparsely-Gauged and Ungauged Areas of Central Chile

Estimating intensity−duration−frequency (IDF) curves requires local historical information of precipitation intensity. When such information is unavailable, as in areas without rain gauges, it is necessary to consider other methods to estimate curve parameters. In this study, three methods were explored to estimate IDF curves in ungauged areas: Kriging (KG), Inverse Distance Weighting (IDW), and Storm Index (SI). To test the viability of these methods, historical data collected from 31 rain gauges distributed in central Chile, 35° S to 38° S, are used. As a result of the reduced number of rain gauges to evaluate the performance of each method, we used LOOCV (Leaving One Out Cross Validation). The results indicate that KG was limited due to the sparse distribution of rain gauges in central Chile. SI (a linear scaling method) showed the smallest prediction error in all of the ungauged locations, and outperformed both KG and IDW. However, the SI method does not provide estimates of uncertainty, as is possible with KG. The simplicity of SI renders it a viable method for extrapolating IDF curves to locations without data in the central zone of Chile

LATITUDINAL ANALYSIS OF RAINFALL INTENSITY AND MEAN ANNUAL PRECIPITATION IN CHILE

The study and analysis of precipitation has become a crucial tool in understanding the temporal and spatial behavior of water resources, in terms of availability and impact on extreme events. The objective of this study was to evaluate different rainfall parameters (intensities for 1-h duration D = 1 h and return periods of T = 5 and 100 yr, and mean annual precipitation) for different latitudinal and climatic zones in Chile. We analyzed the information recorded on thousands of pluvial bands and rain gauges for 49 stations; this because it is unclear how rainfall intensities change along the country (though total amounts do), in addition to a lack of literature focused on ranges and amounts on the behavior of rainfall variables. The Gumbel probability distribution function (PDF) and mathematical rainfall intensity formulas were used to develop intensity-duration-frequency (IDF) curves for each station. Maximum and minimum rainfall intensity values for T = 100 yr ranged from 8.79 (hyperarid zone) to 40.17 mm h-1 (subhumid-humid zone). Total annual rainfall values ranged between 43.9 (hyperarid zone) and 3891.0 mm yr-1 (humid zone). Additionally, the real maximum intensity registered on each station was analyzed, determining its exceedance probability. Likewise, multiple comparisons were made to detect significant differences between the gauge stations and different climatic zones using the Kruskal Wallis test (alpha = 0.05). Differences between maximum and minimum values registered for all stations were as much as 80 times for total rainfall amounts and 4.5 times for rainfall intensities (T = 100 yr). However, maximum rainfall intensities values were similar at different latitudes, suggesting the absence of correlation between maximum rainfall intensity and annual rainfall amount, as the latter variable increased gradually with latitude

Hydrologic Analysis of an Intensively Irrigated Area in Southern Peru Using a Crop-Field Scale Framework

Majes is one of the largest agricultural areas in the Arequipa region (southern Peru). Low seasonal precipitation and increasing water demands for agricultural irrigation, industry, and human consumption have made water supply projections a major concern. Agricultural development is becoming more extensive in this dry, sunny climate where crops can be grown year-round. However, because this type of project usually involves significant perturbations to the regional water cycle, understanding the effects of irrigation on local hydrology is crucial. Based on the watershed-scale Soil and Water Assessment Tool (SWAT), this investigation focuses on the impacts of intensive irrigation on hydrological responses in the Majes region. This study is unique because we allow for crop-field scale input within our regional-scale model to provide information at this smaller scale, which is important to inform local stakeholders and decision makers. Each hydrologic response unit (HRU) was generated to represent an individual crop field, so that management practices could be applied according to real-world scenarios. The management file of each HRU was modified to include different operation schedules for crop rotation, irrigation, harvest, and tillage. The model was calibrated and validated against monthly observed stream discharge during the 2009–2020 period. Additionally, evapotranspiration, irrigation water volume, and daily stream discharge downstream of the local river (Siguas) were used to verify the model performance. A total of 49 sub-basins and 4222 HRUs were created, with 3000 HRUs designated to represent individual crop fields. The simulation results revealed that infiltration from agricultural activities in Majes represents the majority of annual groundwater return flow, which makes a substantial contribution to streamflow downstream of the Siguas River. Simulations also suggested that groundwater flow processes and the interactions between surface and groundwater have a major impact on the water balance of the study area. Additionally, climate variability had a higher impact on surface runoff than on groundwater return flow, illustrating that the groundwater component in the study area is important for future water resources resiliency under expected climate change scenarios. Finally, there is a need to perform a follow-up implementation to provide a guideline for decision-makers to assess future sustainable water resources management under varying climatic conditions for this arid irrigated system