SHUVALOVO area First step GWFM

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GeoInforM Project - LIFE06 TCY/ROS/0002673° Steering Committee – ST. Petersburg, 17th-18th April 2008

SHUVALOVO area First step GWFM

Integrating Geological Information in City Management to Prevent Environmental Risks

GeoInforMLIFE06 TCY/ROS/000267

Michel FasoliPiergiorgio Valentini, Roberta Donati

Province of MilanEnvironmental Information System DepartmentCentral Directorate Environmental Resources

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1. Problem Definition

2. Conceptual Model

3. Mathematical Model

4. Numerical Formulation

5. Sensitivity Analysis

6. Calibration

7. Model Application

Modelling phases procedure

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Modelling phases procedure•Aims identification for modelling •Pilot area identification

•Collecting data about pilot area and regional area•Organizing data with GIS software first of all in an ArcMap project and then in a geodatabase with all original data e new data elaboration•Geological and hydrogeological data interpretation•Conceptual model definition

SOIL-GIS 2008

Definition of Modflow and MT3D input: grid cell dimensions, boundary conditions, layers geometry, permeability, recharge, withdrawals, porosity, pollutant concentration, ecc …

•Flow simulation with SOIL-GIS 2008•Transport simulation with SOIL-GIS 2008•Sensitivity analysis compared with K•Calibration limits compared with target wells

Application of the model in the case study after the calibration

PHASE 1

PHASE 2

PHASE 3

PHASE 5-6

PHASE 4

PHASE 7

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Conceptual model

All layers are continuous in the model !!!

GG1 cross-section

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Numerical formulationElevation data from:

• Altitude points• Boreholes (from

database and from sections)• Water levels• Daylight relief • isolines• Lakes fictitious • points• Top inter moraine

isolines• Prequaternary relief

isolines• Tops correction fictitious points

Top of prequaternaryis the bottom of 8

layer

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Numerical formulation Tops Elevation Table

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Numerical formulation

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Tops correction

• The interpolation for some layers (with few elevation points) gives problems of intersections between contiguous layers (see example in the next slide)

• In this case is necessary to put in some fictitious points to avoid the problem

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In this example layer 8 bottom (below/green) intersects layer 8 top (above/grey) in three areas

Tops correction

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3D Surfer representation

9 surfaces elevation

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Modelling methodology

ESRI grid for SOIL-GIS

Tables

3D Surfer grid

Geological andHydrogeological

interpretation Interpolation

GridConvert

GEODB

DatabaseShapefiles

Raster

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GW aquifer Boundary conditions (layers 1-2-3)

Constant head Lakes as

constant head

Lakes as constant

head

Rivers

Rivers

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IM aquifer Boundary conditions (layers 5-6-7)

Constant head

Constant head

?

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Discretization domain

Grid cells of 10-50 meters are the ideal to study Shuvalovo area and in particular the lakes, the most important elements to modelling.

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In the next future …The next steps will be the definition of:

• permeability grids for each layers (we will simulate a situation with minimum K values and another with maximum K values);

• porosity grids estimate from K values;

• withdrawals grids (known or estimated);

• recharge grids (% infiltration);

• wells as control target.

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Permeability

K range

?

?

Is correct?

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Permeability

Dusty sand in Lithology.shpFine sand in Boreholes.mdb

?

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PermeabilityVarious grain size sand

in Lithology.shpMedium grain size sand

in Boreholes.mdb

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Piezometry

Differences between GW_Water_level_max.shp in blue and Daylight_Relief.shp in black

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Piezometry

Differences between GW_Water_level_max.shp in blue and interpolation of GW boreholes maximum water level in red

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Piezometry

Differences between IM_Water_level_max.shp in blue and interpolation of IM boreholes minimum water level in red

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DEM

Differences between Daylight_Relief.shp in black and interpolation of altitude points in red

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Flow expected results

• Static and dynamic piezometric surface (checked with target control)

• Water exchange estimate between GW aquifer and IM aquifer according to reciprocal K values

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To respect the future actions of the Province of Milan we need to know the data necessary for a complete flow and transport simulation

Future actions

?

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THANKS

for your precious attention !!!

SHUVALOVO area First step GWFM

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