The suggested methodology concerns the structural reconstruction of the shallow aquifer in the distal meander plain of Lombardy region. The aim of the work is to reproduce the heterogeneity of the fluvial and the glacio-fluvial sediments in the subsoil and the heterogeneity of hydraulic conductivity and effective porosity, that may be the input of a groundwater flow model. We would like to exceed the strong subdivision into aquifers and aquitards and to introduce the concept of textural changing inside an aquifer. The first step is a detailed quantitative reconstruction of subsoil textural characteristics in the study area. It is necessary to collect and store in a specific hydrologic database, TANGRAM, the highest and the most reliable number of georeferenced water wells with their own stratigraphic data: each stratigraphic level is codified and, during the extraction step, is translated in textural percentage classes (gravel, sand and clay) according to a vertical subdivision, chosen by the user. The second step is to estimate the hydraulic conductivity and effective porosity values, used a linked database module. Literature values for the parameters of cobbles, gravel, sand and clay are taken into account. The idea is to associate a value of hydraulic conductivity or effective porosity with different textural percentages, weighted by the scaling described approach. The last step is to link the specific hydrologic database and a three-dimensional modelling software GOCAD (Geological Object Computer Aided Design). The data, extracted from Tangram, are elaborated within a three-dimensional grid, built according to the boundary surfaces of the hydrogeological system (the topographic surface and the aquifer bottom): the properties are interpolated, using the powerful three-dimensional interpolator inside Gocad. Results are a three-dimensional rebuilding of the heterogeneous distribution of textural percentages or hydraulic parameters into the whole studied volume of the subsoil. This procedure has been used within some different province in Lombardy, like Lodi and Cremona, where more than 1000 stratigraphic data were collected, codified and stored. In this work the first results are shown.

Bonomi, T., Canepa, P., DEL ROSSO, F., Crestana, B., Vergani, E. (2009). Ricostruzione delle caratteristiche tessiturali e dei parametri idraulici nella bassa pianura lombarda (Lodi e Cremona). RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 8, 14-18.

Ricostruzione delle caratteristiche tessiturali e dei parametri idraulici nella bassa pianura lombarda (Lodi e Cremona)

BONOMI, TULLIA;CANEPA, PAOLA;DEL ROSSO, FRANCESCA;
2009

Abstract

The suggested methodology concerns the structural reconstruction of the shallow aquifer in the distal meander plain of Lombardy region. The aim of the work is to reproduce the heterogeneity of the fluvial and the glacio-fluvial sediments in the subsoil and the heterogeneity of hydraulic conductivity and effective porosity, that may be the input of a groundwater flow model. We would like to exceed the strong subdivision into aquifers and aquitards and to introduce the concept of textural changing inside an aquifer. The first step is a detailed quantitative reconstruction of subsoil textural characteristics in the study area. It is necessary to collect and store in a specific hydrologic database, TANGRAM, the highest and the most reliable number of georeferenced water wells with their own stratigraphic data: each stratigraphic level is codified and, during the extraction step, is translated in textural percentage classes (gravel, sand and clay) according to a vertical subdivision, chosen by the user. The second step is to estimate the hydraulic conductivity and effective porosity values, used a linked database module. Literature values for the parameters of cobbles, gravel, sand and clay are taken into account. The idea is to associate a value of hydraulic conductivity or effective porosity with different textural percentages, weighted by the scaling described approach. The last step is to link the specific hydrologic database and a three-dimensional modelling software GOCAD (Geological Object Computer Aided Design). The data, extracted from Tangram, are elaborated within a three-dimensional grid, built according to the boundary surfaces of the hydrogeological system (the topographic surface and the aquifer bottom): the properties are interpolated, using the powerful three-dimensional interpolator inside Gocad. Results are a three-dimensional rebuilding of the heterogeneous distribution of textural percentages or hydraulic parameters into the whole studied volume of the subsoil. This procedure has been used within some different province in Lombardy, like Lodi and Cremona, where more than 1000 stratigraphic data were collected, codified and stored. In this work the first results are shown.
Articolo in rivista - Articolo scientifico
Heterogeneity, hydrologic database, three-dimensional rebuilding
Italian
2009
8
14
18
none
Bonomi, T., Canepa, P., DEL ROSSO, F., Crestana, B., Vergani, E. (2009). Ricostruzione delle caratteristiche tessiturali e dei parametri idraulici nella bassa pianura lombarda (Lodi e Cremona). RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 8, 14-18.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/43593
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