The Arno basin is rich in superficial and underground water resources, intensively exploited in the past for water supply services, and for agricultural and industrial uses as well. Our Authority carried on in 2006 a detailed inventory of all water abstraction points in the basin, collecting more than 22.000 superficial withdrawals and more than 100.000 wells. At this time we’re engaged in the maintenance of this database (checking, integrating, extending), with the aim to update our water balance plan, both for surface and groundwater. An updated, detailed water balance is one of the main measures foreseen in the River Basin Management Plan: in our opinion, an effective improvement of environmental conditions is feasible and sustainable only with such an objective and solid knowledge. And more than ever, in a changing climate. In this framework, quantitative trends recognition for groundwater bodies is the big question. In situ monitoring, even with a high number of points (like in our region), reveals only a partial and temporal limited validity. New monitoring techniques can give us a good answer to this need. In our contribution we’re going to show some application of interferometric data gathered from synthetic aperture radar. Since 2003 this type of data has been collected and elaborated from our office; first with the SLAM project with University of Florence Service for Landslide Monitoring, then exploiting the Extraordinary Monitoring Plan of Italian Environmental Ministry. The goals of this application are: - investigate of correlation between superficial terrain deformation (derived from interferometric data analysis) and groundwater exploitation and quantitative trends; - define a quantitative evaluation of anthropic pressure and their impact over aquifers.

1. Using Radar Interferometric Satellite Data
for Groundwater Management in the Arno
River Basin
Bernardo Mazzanti, Giovanni Montini
Arno River Basin Authority (I)

2. The Arno River Basin

3. The Arno River Basin
9121 sq. km
High anthropic pressures
2,2 Ml inhabitants

4. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4000+ points in the GWB
perimeter

5. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4000+ points in the GWB
perimeter

6. PSInSar Technique (TRE - Univ. of Milano)
PSP-DIFSAR Technique (Telespazio)

7. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4000+ points in the GWB
perimeter

8. The Arno River Basin
17 aquifers
calibrated model on monthly scale

9. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4000+ points in the GWB
perimeter

10. Land cover map Corine Land cover Level III

11. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4.000+ points in the GWB
perimeter

12. Stratigraphic data in more than
4000 point in every GWB

13. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4000+ points in the GWB
perimeter

14. Evaluation of subsidence phenomenaDefinition procedure of EWZN vector

15. Highlighting most affected areasMain direction of EWZN vector

16. Choice of descending patternComparison of mean yearly PS velocity

17. High mean deformation valuesDistribution of EWZN vector velocity component

18. Goal
Methods
Data
Analisys of correlation between superficial terrain
deformation (at regional scale) and water exploitation
in alluvial groundwater
Impact evaluation of anthropic pressures on water
bodies
Persistent Scatterers from radar interferometric data
(ENVISAT 2003-2010)
Water balance of 17 aquifers in the Arno river basin
Updated CORINE land cover map at high resolution
(1:10.000)
Preliminary deformation analysis at regional scale
Detailed analysis of subsidence phenomena for each
water body
Stratigraphic data in 4000+ points in the GWB
perimeter

19. Index #1
Mean deformation velocity
evaluated on every GWB
Low
Vavg
> -2 mm/y
Medium
-2 < Vavg
> -5 mm/y
High
Vavg
< -5 mm/y
Index #2 % active PS in populated areas
Low
<= 10%
Medium
10% - 30%
High
> 30%
Index #3
Ratio between avg. deformation
velocity in populated areas and
avg. deformation velocity in the
whole GWB
Low
< 1.05
Medium
1.05 - 1.15
High
> 1.15

20. Index evaluation on every GWB

21. Highlighting impact on anthropic activities
& water abstraction as a driver for subsidence
Spatial comparison of Index 1/2/3

22. Mid-term exploitation evaluation
GWB critical condition classification
from water balance and quality monitoring
low
medium
high

23. Highlighting most affected areas
Statistical analysis of deformations
according to land cover type
Index evaluation on a single GWB

28. Normalized index sum

29. ENVISAT data (2003-2010)

30. ERS data (1992-2000)

31. Conclusions
Useful characterization of
subsidence phenomena
Interferometric data
analysis
Helpful for spatial description
and impact evaluation
Integration with
geological and
land cover data
High correlation with over-
exploited grundwater bodies
Comparison with
water abstraction
data

32. Thank You
Merci
‫ﺟراﺗﺳﻲ‬
Bernardo Mazzanti
Arno River Basin Authority
via dei Servi 15 - 50122 - Florence (Italy)
http://www.adbarno.it
Thanks to: