提出了对南美内在含水层脆弱性的评估。结果代表了天然含水层对从陆地表面浸出溶解化合物的潜在敏感性。这项研究,在大陆尺度上发展,但在区域上保持高分辨率,基于DRASTIC方法的关键应用。在南美进行此类研究的最大挑战是环境数据集的分散和不规则性。因此,关于土壤的最新信息,土地利用,地质学,水文地质学,和大陆性气候,国家,从国际和本地数据库中选择区域规模。为了避免空间差异和不一致,数据被整合,协调,并准确地交叉检查,在缺少信息的地方使用当地专业知识。该方法已在GIS环境中应用,以允许对原始数据进行空间分析以及对地图进行叠加和评级。DRASTIC方法的应用允许将南美分为五个漏洞类别,从很低到很高,并在大陆范围内显示出总体上中等到低的脆弱性。亚马逊地区,沿海含水层,安第斯山谷合流,主要河流的冲积含水层被列为高度脆弱的地区。此外,含水层脆弱性最大地区的国家是雨林面积扩大的国家。此外,单参数敏感性分析表明,对地下水位的深度是最重要的因素,虽然使用现有的脆弱性评估和地下水中观察到的化合物浓度进行了交叉验证,证实了拟议评估的可靠性,甚至在区域范围内。总的来说,尽管需要额外的实地调查和地方一级的详细工作来制定有效的水管理计划,当前的DRASTIC地图代表了在整个南美领土上实现更可持续的土地利用和水资源管理的重要共同点。
An assessment of the intrinsic aquifer vulnerability of South America is presented. The outcomes represent the potential sensitivity of natural aquifers to leaching of dissolved compounds from the land surface. The study, developed at continental scale but retaining regionally a high resolution, is based on a critical application of the
DRASTIC method. The biggest challenge in performing such a study in South America was the scattered and irregular nature of environmental datasets. Accordingly, the most updated information on soil, land use, geology, hydrogeology, and climate at continental, national, and regional scale were selected from international and local databases. To avoid spatial discrepancy and inconsistency, data were integrated, harmonized, and accurately cross-checked, using local professional knowledge where information was missing. The method was applied in a GIS environment to allow spatial analysis of raw data along with the overlaying and rating of maps. The application of the
DRASTIC method allows to classify South America into five vulnerability classes, from very low to very high, and shows an overall medium to low vulnerability at continental scale. The Amazon region, coastal aquifers, colluvial Andean valleys, and alluvial aquifers of main rivers were the areas classified as highly vulnerable. Moreover, countries with the largest areas with high aquifer vulnerability were those characterized by extended regions of rainforest. In addition, a single parameter sensitivity analysis showed depth to water table to be the most significant factor, while a cross-validation using existing vulnerability assessments and observed concentrations of compounds in groundwater confirmed the reliability of the proposed assessment, even at regional scale. Overall, although additional field surveys and detailed works at local level are needed to develop effective water management plans, the present
DRASTIC map represents an essential common ground towards a more sustainable land-use and water management in the whole territory of South America.