Storm-water infiltration and focused recharge modeling with finite-volume two-dimensional Richards equation: application to an experimental rain garden

Rain gardens are infiltration systems that provide volume and water quality control, recharge enhancement, as well as landscape, ecological, and economic benefits. A model for application to rain gardens based on Richards equation coupled to a surface water balance was developed, using a two-dimensional finite-volume code. It allows for alternating upper boundary conditions, including ponding and overflow, and can simulate heterogeneous soil-layering or more complex geometries to estimate infiltration and recharge. The algorithm is conservative, and exhibits good performance compared to standard models for several test cases (less than 0.1% absolute mass balance error); simulations were also performed for an experimental rain garden and comparisons to collected data are presented. The model accurately simulated the matrix flow, soil water distribution, as well as deep percolation (potential recharge) for a natural rainfall event in the controlled experimental setup. Read More: http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29HY.1943-7900.0000111?prevSearch=authors%3A%28Dussaillant%2C%29&searchHistoryKey

La neutralidad como forma de encuadre en una campaña electoral

Analiza los aspectos teóricos del framing presentando la neutralidad como una de las múltiples o ilimitadas formas en que este se puede manifestar. Sostiene que el encuadre o enfoque que los medios de comunicación den a la cobertura de una campaña electoral, y especialmente a los atributos o rasgos personales de un candidato, tendrá incidencia en la opinión pública, incluso cuando se opte por mecanismos de framing que beneficien o faciliten que el público reciba el mensaje encuadrado por los mismos candidatos, como puede suceder con la neutralidad. Concluye que en la campaña presidencial chilena de 1999 se facilitó que se impusiera el encuadre del mensaje de los candidatos por sobre el framing de los medios

Predicting infiltration and pollutant retention in sustainable drainage systems: Experiments, modelling and design

A major problem of increasing urbanization is the rise in pollution caused by runoff, affecting water quality directly and due to combined sewer overflows. Among alternative strategies, Sustainable Drainage Systems (SuDS) such as rain gardens and other bioretention facilities is becoming more widespread. Previous research has focused primarily on hydrologic design, including the degree to which groundwater is replenished by these systems, and models have been developed to quantify the extent of that enhanced focused recharge. However, there are few tools for their design that adequately consider pollutant retention. We have developed a numerical model that simulates infiltration into different area systems with porous media of up to three layers, and can simulate movement and accumulation of metals considering macropore flow. This model is here further validated using new laboratory column results (for matrix and macropore flow), and applied to the design of a rain garden system for a planned roundabout in Kent, U.K, considering climate change scenarios. Results using past and potential future climate series show levels of lead can build up in the upper layers of the system, but only constitute a health hazard after approximately 10 years (when a management intervention such as replacing the upper few cm of soil is required). Implications and future opportunities are discussed

Ice Dynamics and Morphological Changes During Proglacial Lake Development at Exploradores Glacier, Patagonia

Proglacial lakes are ubiquitous features formed during deglaciarization and are currently increasing in number in Patagonia and elsewhere. Proglacial lakes can affect glacier dynamics, catchment hydrology and have the potential to cause glacial lake outburst floods. Therefore, monitoring the onset and development of proglacial lake formation is relevant to understand glacial processes and anticipate glacier response to climate change. In this study, we integrate geomorphological and ice-dynamic information to assess proglacial lake development in Exploradores Glacier, Chilean Patagonia. We monitor recent spatial and temporal changes in the lower trunk of Exploradores Glacier (10 km2) to provide a 20-year observation record by combining eight uncrewed aerial vehicles (UAV) surveys between 2019 and 2020, with high-medium resolution satellite imagery (Rapid Eye and Landsat) between 2000 and 2018. We use feature tracking techniques, digital surface elevation model analysis and field data to create a multi-temporal scale (inter-annual and seasonal) and a multi-spatial (cm to km) data set. Our analysis shows that surface velocity overall trend has not changed over the last 20 years and that surface velocity near the terminus is significant (>10 m a−1). Moreover, an exceptional advance over moraine deposits was detected. We also found low downwasting rates (<0.5 m a−1) close to the glacier terminus which are attributed to sufficient ice flux and the insulation effect of the debris-covered surface. However, hundreds of supraglacial ponds were observed and are currently coalescing and expanding by ice-cliff backwasting favoring glacier disintegration. Lastly, it was found that calving losses at the east marginal lake equaled ice-flux input into the lake for the UAV monitored period. This study contributes to a better understanding of glacial lake dynamics during proglacial lake development, and our results may help ice modelling efforts to predict glacier response to future climate scenarios

Voz sin voto: las crónicas políticas de Inés Bunster (1939)

This article studies the unpublished drafts and published chronicles of Inés Bunster in El Imparcial de Santiago in 1939. We are interested in discovering the topics covered by the author in order to understand the reasons that inspire a woman to write about politics in this liberal evening paper. As a witness to the first year of the Popular Front government in Chile and the outbreak of World War II, her comments on the political contingency constitute a way of participating in a public space occupied mostly by men. We conclude that among his main concerns was the possibility that the atrocities observed in the Spanish Civil War and German expansionism could have repercussions on Chilean soil.Este artículo estudia los borradores inéditos y las crónicas publicadas de Inés Bunster en El Imparcial de Santiago en 1939. Nos interesa descubrir los temas tratados por la autora para entender las razones que inspiran a una mujer a escribir sobre política en este vespertino liberal. Como testigo del primer año de gobierno del Frente Popular en Chile y del estallido de la Segunda Guerra Mundial, sus comentarios sobre la contingencia política constituyen una forma de participar en un espacio público ocupado mayoritariamente por hombres. Concluimos que entre sus principales preocupaciones estaba la posibilidad de que las atrocidades observadas en la Guerra Civil Española y el expansionismo alemán pudieran repercutir en suelo chileno

Ice Dynamics and Morphological Changes During Proglacial Lake Development at Exploradores Glacier, Patagonia

Proglacial lakes are ubiquitous features formed during deglaciarization and are currently increasing in number in Patagonia and elsewhere. Proglacial lakes can affect glacier dynamics, catchment hydrology and have the potential to cause glacial lake outburst floods. Therefore, monitoring the onset and development of proglacial lake formation is relevant to understand glacial processes and anticipate glacier response to climate change. In this study, we integrate geomorphological and ice-dynamic information to assess proglacial lake development in Exploradores Glacier, Chilean Patagonia. We monitor recent spatial and temporal changes in the lower trunk of Exploradores Glacier (10 km2) to provide a 20-year observation record by combining eight uncrewed aerial vehicles (UAV) surveys between 2019 and 2020, with high-medium resolution satellite imagery (Rapid Eye and Landsat) between 2000 and 2018. We use feature tracking techniques, digital surface elevation model analysis and field data to create a multi-temporal scale (inter-annual and seasonal) and a multi-spatial (cm to km) data set. Our analysis shows that surface velocity overall trend has not changed over the last 20 years and that surface velocity near the terminus is significant (&gt;10 m a−1). Moreover, an exceptional advance over moraine deposits was detected. We also found low downwasting rates (&lt;0.5 m a−1) close to the glacier terminus which are attributed to sufficient ice flux and the insulation effect of the debris-covered surface. However, hundreds of supraglacial ponds were observed and are currently coalescing and expanding by ice-cliff backwasting favoring glacier disintegration. Lastly, it was found that calving losses at the east marginal lake equaled ice-flux input into the lake for the UAV monitored period. This study contributes to a better understanding of glacial lake dynamics during proglacial lake development, and our results may help ice modelling efforts to predict glacier response to future climate scenarios

Geomorphologic impact of outburst flood cycle in braided gravel-bed rivers: confluence of Colonia and Baker rivers, Patagonia, Chile

Colonia River, as other glacial streams influenced by global warming, is affected by Glacial Lake Outburst Floods (OF). We present a study on geomorphologic features of Colonia River to comprehend the impact of OFs in sedimentary processes, analysing erosion and deposition linked to OF phenomena and frequency (since April 2008, more than 12 OFs have occurred). Interpolation analysis is carried out to create an elevation surface (DTM) from a set of sample measurements, given by contour line (2007 LiDAR) and rtkGPS point (2011 and 2012) data. These were used to create DTMs applying Delaunay triangulation. A comparisons between morphology during the current OF cycle that started on 8 April 2008, and the previous morphology (after 40 years without OFs, since end of previous cycle in 1968), is carried out through the creation of DEMs of Difference (DoDs) based on TINs. We created two DoDs, respectively between 2011-2007 (before/after the OFs cycle) and 2012-2011 (during the cycle, after the events of January and April 2012) to provide a high-resolution, spatially distributed surface model of topographic and volumetric change through time. The floodplain has been classified on the basis of the morphological characteristics: main and secondary channel(s), bars, braided area, island and delta fan features. The changes evidenced in the DoD are segregated according to these categories plus the geomorphic change taking place in each category (using GCD; Wheaton et al 2014). Issues regarding data quantity and quality will be discussed, and implications for the planned mega-dam that would flood the confluence