Bonifica e controllo della contaminazione da organoclorurati

GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
GIS processing to support an
Hydrogeological Flux and Transport
Model in Cecina Plain (LI, PI)
Riccardo Armellini**, Elena Baldini*, Dario Del Seppia*, Fabrizio Franceschini*, Natacha
Gori***, Stefano Menichetti*, Stefano Tessitore*
*ARPAT Agenzia Regionale di Protezione Ambientale della Toscana Direzione Tecnica, Dipartimenti Pisa
e Livorno.
** Master AA 2011/2012 in Sistemi Informativi Territoriali per la Gestione del territorio UNIFI
*** Diploma di Corso di Laurea Triennale in Scienze Ambientali UNIPI - [email protected]
Montefalco (PG), 16 - 19 giugno 2014
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Geographical Setting
The study area is located within the provinces of Pisa and Livorno at south of
Cecina river, in Montescudaio and Cecina municipalities
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
2004:
History of contamination
• pollution by tetrachlorethylene (PCE) and trichlorethylene (TCE) in groundwater of Cecina
with exceedances of limits for drinking water (total PCE + TCE = 10 µg/L)
• investigative monitoring:
- source area of contamination located in the industrial area of Poggio Gagliardo,
east of the town of Cecina
- contaminant plume that spreads towards the town of Cecina.
• in many wells monitored exceedances
of CSC for contaminated sites (1.1
µg/L for PCE and 1.5µg/L for TCE)
• Agreement Program (DPGR 363/04)
between RT and territorial authorities
to coordinate joint actions for the
implementation of emergency safety
and remediation of ground water.
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
2004-2012:
History of contamination
• securing emergency (MISE): hydraulic barrier with installation systems Pump & Treat in
the source area, pumping calibration and installation of carbon filters in the wells of the
aqueduct.
• monitoring plume: major boost with the rains 2009-2010
• characterization and remediation project
2012-2013:
• monitoring plume assisted by a model
of flow and transport
• start cleaning up: upgrading and
reconfiguring hydraulic barrier, sealing
or reconditioning wells in the source
2014 =>
• completion of reclamation: removal of
free phase DNAPL by SVE and P & T in
the source area
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Mappe isocone del plume inquinante
Ricostruzioni basate sui valori medi annuali dell’indicatore chiave somma PCE+TCE .
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Mappe isocone del plume inquinante
Ricostruzioni basate sui valori medi annuali dell’indicatore chiave somma PCE+TCE .
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Mappe isocone del plume inquinante
Ricostruzioni basate sui valori medi annuali dell’indicatore chiave somma PCE+TCE .
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Modeling
1. Conceptual Model
2. GIS processing
Geometry reconstructions
 Estimation of hydraulic conductivity
 Calculation of inflows
 Withdrawals
 Piezometric reference
3. Model of flow and transport
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Conceptual Model
STECCAIA
1. MULTILAYER AQUIFER in Quaternary
marine and continental deposits: single
hydrogeological domain bordered by
Cecina river, Le Basse creek, the coastline
and an elevation, hydrological and
IGG CNR LAMMA (2009) –
CISS characterization:
isobaths 32CT010 +
32CT030
geological discontinuity between hills
(lower pleistocene) and plain terraces
(medium upper pleistocene);
2. AQUIFER – RIVER CONNECTION, very
strong in Steccaia area;
3. LOCALY MULTILEVEL AQUIFER: in
contaminated area a clayey interlayer
separates a very contaminated shallow
water table;
4. TECTONIC CONTROL: a fault along Linaglia
creek interrupts continuity of interlayer.
Benvenuti et alii 2008
- Tectonic and
climatic controls on
historical landscape
modifications: The
avulsion of the lower
Cecina River
(Tuscany, central
Italy)
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
GIS PROCESSING: geometry reconstructions
• Integration of regional survey database SIRA_DB-GEO: 97 new logs with 1133 layers
• LITHOLOGICAL interpretation: classification of each layer lithotype as AQUIFER, AQUITARD
or AQUICLUDE on the basis of intrinsic permeability (K).
• GEOLOGICAL interpretation: classification
according CARG’s synthems and lithofacies
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Hydrogeological interpretation
• HYDROGEOLOGICAL interpretation: definition of hydrogeological units corresponding to
model layer
Hydrogeological units
1 = aquiclude substrate
2 = aquifer undifferentiated
2a = deep aquifer
2b = aquiclude aquitard interlayer
2c = shallow aquifer
3 = aquiclude aquitard cover
• Surface modeling using the Kriging ArcGIS Geostatistical Analyst extension
• Geometric corrections, needed especially on the sides of the domain, and calculation of
thickness using the Raster Calculator tool Spatial Analyst extension.
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Hydrostructural maps
Modeling products => SURFACES and THICKNESS maps of HYDROGEOLOGICAL UNITS.
COVERAGE thickness
• average thickness
ranging from 5 to 8
meters
• max thickness on hill
reliefs
• tectonic control by
Linaglia and other
faults that marks
several thickness
discontinuity
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Hydrostructural maps
Modeling products => SURFACES and THICKNESS maps of HYDROGEOLOGICAL UNITS.
INTERLAYER top
• sloping to the Cecina
follows the
morphology of the
reliefs
• the source area
coincides with an
incision sloping
towards southwest
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Hydrostructural maps
Modeling products => SURFACES and THICKNESS maps of HYDROGEOLOGICAL UNITS.
INTERLAYER thickness
• Average thickness
ranging from 10 to 15
meters
• Maximum thickness
zone downstream of
Steccaia
• Local maximum near
the contaminated area
of Poggio Gagliardo
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Hydrostructural maps
Modeling products => SURFACES and THICKNESS maps of HYDROGEOLOGICAL UNITS.
AQUIFER thickness
• average thickness of
45 meters
• minimum thicknesses
area in interlayer area
• max thickness areas at
hilly reliefs and town
of Cecina
• appreciable tectonic
control by Linaglia and
other faults
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Hydrostructural maps
Modeling products => SURFACES and THICKNESS maps of HYDROGEOLOGICAL UNITS.
AQUIFER bottom
• Sloping to the Cecina
and the sea with the
presence of a northsouth depression
• Max depth - 46.5
meters s.l.m at Cecina
town
• Min depth - 3.3
meters s.l.m. at hilly
reliefs
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Model of flow and transport
• Modeling Software: Groundwater Vistas 5
• Numerical code MODFLOW: three-dimensional flow equations in a porous medium –
finite difference method (FDM)
Input data => "packages“ files
• Boundary Conditions (BCs): imposed conditions which the differential equation must
comply with
• Properties: apply to aquifer cells (elevations, conductivity, storativity, recharge)
• Analytic Elements (AE): apply at precise location (wells, target with observed heads)
Stages of implementation:
• Rev0 => steady state natural
• Rev1 => Rev0 + wells withdrawaL
• Rev2 => Rev1 + hills constant flow boundary
• Rev3 => Rev1 + Cecina “River” boundary
• Rev4 => Rev3 divided into 4 layers
Simulation of past, actual and forecast scenarios:
• Rev3.0 => pre 2004 scenario (no MISE)
• Rev3.1 => 2004 MISE with detail telescopic mesh refinement (Rev3.1.tmr)
• Rev3.2 => 2012 MISE increase (Rev3.2.tmr)
• Rev3.3.tmr => forecast scenario for MISE (change in flow rate of activated wells in Rev 3.2)
• Rev3.4.tmr => forecast scenario for MISE (variable flow)
• Rev3.5.tmr => forecast scenario for MISE (hypotesis of reinjection well)
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Steady flow Model: optimization MISE
Rev3.2_tmr => 2012-2013 MISE
Rev3.1 => 2004 – 2012 MISE
Rev 3.4_tmr => 2013 – 2014
MISE model designed
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Model of transient transport 2005 - 2010 (Rev 3)
Recharge, Cecina river heads and wells withdrawals modified according to their temporal
variation in 2005 -2010.
Ladronaia
Peep
S. Vincenzino
 fair / good correspondence in the trends in the case of Peep and Ladronaia, except for
the intensive phase of 2008-2009 where DNAPL separate flow may have occurred;
 differences in the case of St. Vincenzino, probably due to inaccurate reconstruction of
concentration as interpolated by discontinuous data in space and time.
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Predictive transport model: hydrological year 2013-2014
• Rev3.4 version, scenario implemented with the MISE: Q(CD1)>> Q(CD2) = Q(CD3)
• Initial concentrations = concentration of the third quarter of 2013.
Ladronaia
• Forecast scenarios related to hydrological years such
as 2008/2009, which scenario of maximum “wet”
year, and the 2005/2006 minimum “dry” year.
Maximum
Peep
Plume Direction SW with
strong increase towards
the well Peep of Cecina ;
Ladronaia
Minimum
Plume direction SW
But with lateral extent
relative to the flow, to
Ladronaia
Peep
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Forecast Model 2013-2014: Proposal enhancement of MISE
In 2014 Rapida well has been reconditioned and is now filtering the deep aquifer. Model forecast
simulation suggest improvement as Rapida Pump & Treat plant moved to CD4 well.
Fig. 3 Rev3_4_TT13_TMRmin.gwv. Stress period 4 e
Time step 3. - Attuale
Fig. 4 Rev3_5_TT13_TMRmin.gwv. Stress period 4 e
Time step 3 - Proposta
Heads and particle tracking evaluated with the post-processing program MODPATH.
Scenarios minimum
(end of summer hydrologic year 2005-2006)
Fig. 2 Rev3_5_TT13_TMRmax.gwv. Stress period 1 e
Time step 3 - Proposta.
Scenarios maximum
(late autumn hydrological year 2008-2009)
Fig. 1 Rev3_4_TT13_TMRmax.gwv. Stress period 1 e
Time step 3 - Attuale
GIT – Geology and Information Technology
9a Riunione del Gruppo di Geologia informatica - Sezione della Società Geologica Italiana
Montefalco (PG), 16 - 19 giugno 2014
Conclusions
 The present work has increased the knowledge of the hydrogeological system of coastal aquifer
of Cecina, with the main purpose of calibrating withdrawal from the wells of the MISE, in order to
optimize it, and secondary support monitoring of the water body impacted
 At first has been defined the conceptual model of the aquifer system need to set the
development of the model of flow and transport
 By GIS processing it was possible to create several layers of information useful to all stages of
implementation of the steady state and transient flow and transport model;
 A preliminary steady-state “natural”, without withdrawals, simulations have shown the
consistency of the data processed
 Several scenarios were simulated aimed at the optimization of the MISE to confine the plume
 The subsequent reconstruction in transient seasonal and transient in the period 2005-2010
showed a good qualitative agreement between measured and simulated data in the selected
targets
 Present model will assist in the coming years monitoring of contaminant plume and remediation
interventions by reproducing elapsed hydrological year and providing forecasts for minimum and
maximum scenarios

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