Session 2 : Apport de la télédétection dans la mobilisation des ressources en eau : Tunisie
224
ABSTRACT
The objective of this study, carried out by the National Remote Sensing Centre, in
collaboration with the General Directorate for Water Resources of the Ministry of
Agriculture, is the development of a method for the integration of high spatial resolution
satellite data (HRV of SPOT and TM of Landsat) for the elaboration of statistical and
cartographic index of surface water resources (hydrography, lakes, dams, hill reservoirs).
The study has the following objectives:
• prepare a 1/50 000 map of all surface water resources;
• evaluate the potential in surface water in relation to the irrigated surface in the region;
• support resource management through a GIS.
In a first phase, an analog interpretation of a printed SPOT XS image taken in 1990 was
used to identify water surface and very moist areas and to visually interpret the
hydrological network of the Oued Medjerda watershed. The same work was carried out
with a printed Landsat TM image of the same area. This was followed by a phase of digital
processing (classification, thresholding) carried out on the infrared band of SPOT and
LANDSAT to isolate the water theme. A second phase consisted in analysing the surface
water resources in relation to the irrigated perimeters in the region. This treatment
provides a map of the spatial evolution of irrigated areas.
All the numeric results obtained in the form of strata of digital information on water
surface completed with exogenous information provide a useful basis for water resource
management. The contribution or remote sensing consists in a digital map of water
resources from satellite data. The information base generated by this study can help in the
optimisation of the use of the resource in the framework of rural water management in the
region within the objective of the national strategy for the mobilisation of water resources.
INTRODUCTION
La Tunisie, en raison de sa situation géographique, est un pays aride à semi-aride sur la majeure
partie de son territoire. Cette aridité, conjuguée aux caprices du climat méditerranéen, fait de
l’eau une ressource à la fois rare et mal repartie dans l’espace et dans le temps.
Du fait de la rareté des ressources en eau et de la variabilité de sa répartition face à des
besoins sans cesse croissants il est impératif de continuer à accorder au secteur de l’eau
l’importance qu’il mérite, notamment en ce qui concerne les actions d’identification, de
planification et de gestion de ces ressources.
LE BILAN DES RESSOURCES EN EAUX DE SURFACE EN TUNISIE
Le bilan global actualisé par la Direction générale des ressources en eau en 1990 indique un
potentiel global de 4 500 Mm
3
/an reparti comme suit:
• eaux de surface : un potentiel de 2 700 Mm
3
/an dont 2 100 Mm
3
/an sont mobilisables,
• eaux souterraines : un potentiel de 1 840 Mm
3
/an dont la totalité est mobilisable
224
ABSTRACT
The objective of this study, carried out by the National Remote Sensing Centre, in
collaboration with the General Directorate for Water Resources of the Ministry of
Agriculture, is the development of a method for the integration of high spatial resolution
satellite data (HRV of SPOT and TM of Landsat) for the elaboration of statistical and
cartographic index of surface water resources (hydrography, lakes, dams, hill reservoirs).
The study has the following objectives:
• prepare a 1/50 000 map of all surface water resources;
• evaluate the potential in surface water in relation to the irrigated surface in the region;
• support resource management through a GIS.
In a first phase, an analog interpretation of a printed SPOT XS image taken in 1990 was
used to identify water surface and very moist areas and to visually interpret the
hydrological network of the Oued Medjerda watershed. The same work was carried out
with a printed Landsat TM image of the same area. This was followed by a phase of digital
processing (classification, thresholding) carried out on the infrared band of SPOT and
LANDSAT to isolate the water theme. A second phase consisted in analysing the surface
water resources in relation to the irrigated perimeters in the region. This treatment
provides a map of the spatial evolution of irrigated areas.
All the numeric results obtained in the form of strata of digital information on water
surface completed with exogenous information provide a useful basis for water resource
management. The contribution or remote sensing consists in a digital map of water
resources from satellite data. The information base generated by this study can help in the
optimisation of the use of the resource in the framework of rural water management in the
region within the objective of the national strategy for the mobilisation of water resources.
INTRODUCTION
La Tunisie, en raison de sa situation géographique, est un pays aride à semi-aride sur la majeure
partie de son territoire. Cette aridité, conjuguée aux caprices du climat méditerranéen, fait de
l’eau une ressource à la fois rare et mal repartie dans l’espace et dans le temps.
Du fait de la rareté des ressources en eau et de la variabilité de sa répartition face à des
besoins sans cesse croissants il est impératif de continuer à accorder au secteur de l’eau
l’importance qu’il mérite, notamment en ce qui concerne les actions d’identification, de
planification et de gestion de ces ressources.
LE BILAN DES RESSOURCES EN EAUX DE SURFACE EN TUNISIE
Le bilan global actualisé par la Direction générale des ressources en eau en 1990 indique un
potentiel global de 4 500 Mm
3
/an reparti comme suit:
• eaux de surface : un potentiel de 2 700 Mm
3
/an dont 2 100 Mm
3
/an sont mobilisables,
• eaux souterraines : un potentiel de 1 840 Mm
3
/an dont la totalité est mobilisable