Examinando por Autor "Tosi, L."

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  • Artículo
    Embargado
    A retrospective assessment of the hydrological conditions of the Samborombón coastland (Argentina)
    (2014) Carol, E.S.; Braga, F.; Kruse, Eduardo; Tosi, L.
    Coastal wetlands are transitional zones that play an important role as buffers between the land and sea in several ways, such as protecting the land from storm surge and reducing the input of nutrients from surrounding watersheds to the sea. Understanding the influence of human activities on the hydrological conditions of coastal wetlands is of paramount importance for preserving the ecological function and biodiversity of these unique ecosystems. In the last century, the Samborombón coastland (Argentina), which is an extensive intertidal wetland, has been affected by hydraulic projects and human activities. In this study, through a retrospective assessment of the hydrologic conditions, we show the impacts of channelization, embankments and mining on the surficial and groundwater hydrology of the Samborombón wetlands. The results indicate that channelization has promoted tidal flooding and seawater encroachment along the channels. The embankments have separated large areas from the estuary tides; during heavy rainfalls, they act as obstacles and cause the inundation of inland regions while allowing the accumulation of sodium chloride by saltwater evaporation after tidal overtopping events. The freshwater resources in the aquifer of the paleo-coastlines have been seriously damaged by mining of the shell ridges. The halophyl vegetation in the marshlands and the native forest of the shell ridges, which depend on tidal flow and fresh water, respectively, have been threatened. Nevertheless, although the hydrology of the Samborombón coastland has undergone changes, the engineering projects did not permanently modify or damage the surrounding ecosystems. The outcomes of this study will be useful for remediating ecosystems that have been impacted by human activities by following the fundamentals of ecological engineering.
  • Artículo
    Embargado
    Environmental isotopes applied to the evaluation and quantification of evaporation processes in wetlands: a case study in the Ajó Coastal Plain wetland, Argentina
    (2015) Carol, E.; Braga, F.; Da Lio, C.; Kruse, Eduardo; Tosi, L.
    In the Ajó coastal plain, which occurs in the south of the Samborombón Bay, Argentina, certain sectors of the wetland are influenced by the tidal flow, whereas others are not. In the tidally restricted Ajó wetlands, the evapotranspiration process is one of the most important components of the water balance due to fact that the flat morphology and low soil permeability make the flow of surface and groundwater difficult. Although evaporation is an important component of evapotranspiration, a quantitative estimation of this process is still lacking or poorly known. In this work, we quantify the evaporation term in the tidally restricted wetlands by applying isotopic modelling and assessing the hydrological response of the wetland by means of other methodologies, such as satellite imaging and level measurements. The results show that during deficit periods, the total evaporation ranges between 10 and 33% of the local precipitation. In groundwater samples, it fluctuates between 2 and 13%, whereas in surface water it varies between 8 and 20%. Analyses of the water budget, satellite images and water level time series provide evidence on how evaporation processes regulate the hydrology of the wetland. The water balance suggests the occurrence of a deficit period, in which the satellite images show a reduction of the waterlogged areas and lakes, and a lowering in surface and groundwater level is recorded.
  • Artículo
    Acceso Abierto
    Hydromorphologic setting of the Samborombon Bay (Argentina) at the end of the 21st century
    (2013) Tosi, L.; Kruse, Eduardo; Braga, F.; Carol, Eleonora Silvina; Carretero, Silvina; Pousa, Jorge; Rizzetto, F.; Teatini, P.
    We report on the hydrologic and morphologic setting of the Samborombón Bay, Argentina, which is expected at the end of the 21st century as a consequence of possible scenarios of relative sea level rise (RSLR). The geomorphological analysis of the Samborombón coastland points out only minor changes occurred over the last 40 yr. The modifications are mainly related to the construction of canals to enhance the floodplain drainage. A digital elevation model (DEM) obtained by the Shuttle Radar Topography Mission (SRTM) data archive, ad hoc calibrated/validated for the study area, highlights that about 3000 km2 of coastal plain present a morphological setting at high risk of sea flooding. The analysis of sea level and storm surge events recorded from 1905 to 2010 in Buenos Aires provides the RSLR rate and the return period of extreme floods. In addition, vertical land movements (VLM) measured by the permanent GPS stations of Buenos Aires and La Plata allow for the quantification of the eustatic component of the RSLR and estimating a plausible RSLR rate in the Samborombón Bay. Taking into account possible RSLR scenarios at the end of 2100 as resulting from the statistical analysis of (i) tide gauge and GPS time series and (ii) Intergovernmental Panel on Climate Change (IPCC) predictions, the potential effect of the increased sea level on the Samborombón coastland is simulated. The results show that the combined rise of sea levels, surficial waters and groundwater will lead to a new morpho-hydrologic setting of the coastal area, especially in the low-lying southern sector. Here, a coastline retreat up to 40 km is expected, with temporary submersion up to 4000 km2 during storm surges.